tor-parallel-relay-conn/src/or/config.c

/* Copyright (c) 2001 Matej Pfajfar.
 * Copyright (c) 2001-2004, Roger Dingledine.
 * Copyright (c) 2004-2007, Roger Dingledine, Nick Mathewson. */
/* See LICENSE for licensing information */
/* $Id$ */
const char config_c_id[] = \
  "$Id$";

/**
 * \file config.c
 * \brief Code to parse and interpret configuration files.
 **/

#define CONFIG_PRIVATE

#include "or.h"
#ifdef MS_WINDOWS
#include <shlobj.h>
#endif

/** Enumeration of types which option values can take */
typedef enum config_type_t {
  CONFIG_TYPE_STRING = 0,   /**< An arbitrary string. */
  CONFIG_TYPE_UINT,         /**< A non-negative integer less than MAX_INT */
  CONFIG_TYPE_INTERVAL,     /**< A number of seconds, with optional units*/
  CONFIG_TYPE_MEMUNIT,      /**< A number of bytes, with optional units*/
  CONFIG_TYPE_DOUBLE,       /**< A floating-point value */
  CONFIG_TYPE_BOOL,         /**< A boolean value, expressed as 0 or 1. */
  CONFIG_TYPE_ISOTIME,      /**< An ISO-formated time relative to GMT. */
  CONFIG_TYPE_CSV,          /**< A list of strings, separated by commas and
                              * optional whitespace. */
  CONFIG_TYPE_LINELIST,     /**< Uninterpreted config lines */
  CONFIG_TYPE_LINELIST_S,   /**< Uninterpreted, context-sensitive config lines,
                             * mixed with other keywords. */
  CONFIG_TYPE_LINELIST_V,   /**< Catch-all "virtual" option to summarize
                             * context-sensitive config lines when fetching.
                             */
  CONFIG_TYPE_OBSOLETE,     /**< Obsolete (ignored) option. */
} config_type_t;

/** An abbreviation for a configuration option allowed on the command line. */
typedef struct config_abbrev_t {
  const char *abbreviated;
  const char *full;
  int commandline_only;
  int warn;
} config_abbrev_t;

/* Handy macro for declaring "In the config file or on the command line,
 * you can abbreviate <b>tok</b>s as <b>tok</b>". */
#define PLURAL(tok) { #tok, #tok "s", 0, 0 }

/* A list of command-line abbreviations. */
static config_abbrev_t _option_abbrevs[] = {
  PLURAL(ExitNode),
  PLURAL(EntryNode),
  PLURAL(ExcludeNode),
  PLURAL(FirewallPort),
  PLURAL(LongLivedPort),
  PLURAL(HiddenServiceNode),
  PLURAL(HiddenServiceExcludeNode),
  PLURAL(NumCpu),
  PLURAL(RendNode),
  PLURAL(RendExcludeNode),
  PLURAL(StrictEntryNode),
  PLURAL(StrictExitNode),
  { "l", "Log", 1, 0},
  { "AllowUnverifiedNodes", "AllowInvalidNodes", 0, 0},
  { "AutomapHostSuffixes", "AutomapHostsSuffixes", 0, 0},
  { "AutomapHostOnResolve", "AutomapHostsOnResolve", 0, 0},
  { "BandwidthRateBytes", "BandwidthRate", 0, 0},
  { "BandwidthBurstBytes", "BandwidthBurst", 0, 0},
  { "DirFetchPostPeriod", "StatusFetchPeriod", 0, 0},
  { "MaxConn", "ConnLimit", 0, 1},
  { "ORBindAddress", "ORListenAddress", 0, 0},
  { "DirBindAddress", "DirListenAddress", 0, 0},
  { "SocksBindAddress", "SocksListenAddress", 0, 0},
  { "UseHelperNodes", "UseEntryGuards", 0, 0},
  { "NumHelperNodes", "NumEntryGuards", 0, 0},
  { "UseEntryNodes", "UseEntryGuards", 0, 0},
  { "NumEntryNodes", "NumEntryGuards", 0, 0},
  { "ResolvConf", "ServerDNSResolvConfFile", 0, 1},
  { "SearchDomains", "ServerDNSSearchDomains", 0, 1},
  { NULL, NULL, 0, 0},
};
/* A list of state-file abbreviations, for compatibility. */
static config_abbrev_t _state_abbrevs[] = {
  { "AccountingBytesReadInterval", "AccountingBytesReadInInterval", 0, 0 },
  { "HelperNode", "EntryGuard", 0, 0 },
  { "HelperNodeDownSince", "EntryGuardDownSince", 0, 0 },
  { "HelperNodeUnlistedSince", "EntryGuardUnlistedSince", 0, 0 },
  { "EntryNode", "EntryGuard", 0, 0 },
  { "EntryNodeDownSince", "EntryGuardDownSince", 0, 0 },
  { "EntryNodeUnlistedSince", "EntryGuardUnlistedSince", 0, 0 },
  { NULL, NULL, 0, 0},
};
#undef PLURAL

/** A variable allowed in the configuration file or on the command line. */
typedef struct config_var_t {
  const char *name; /**< The full keyword (case insensitive). */
  config_type_t type; /**< How to interpret the type and turn it into a
                       * value. */
  off_t var_offset; /**< Offset of the corresponding member of or_options_t. */
  const char *initvalue; /**< String (or null) describing initial value. */
} config_var_t;

/** An entry for config_vars: "The option <b>name</b> has type
 * CONFIG_TYPE_<b>conftype</b>, and corresponds to
 * or_options_t.<b>member</b>"
 */
#define VAR(name,conftype,member,initvalue)                             \
  { name, CONFIG_TYPE_ ## conftype, STRUCT_OFFSET(or_options_t, member), \
      initvalue }
/** As VAR, but the option name and member name are the same. */
#define V(member,conftype,initvalue)                                    \
  VAR(#member, conftype, member, initvalue)
/** An entry for config_vars: "The option <b>name</b> is obsolete." */
#define OBSOLETE(name) { name, CONFIG_TYPE_OBSOLETE, 0, NULL }

/** Array of configuration options.  Until we disallow nonstandard
 * abbreviations, order is significant, since the first matching option will
 * be chosen first.
 */
static config_var_t _option_vars[] = {
  OBSOLETE("AccountingMaxKB"),
  V(AccountingMax,               MEMUNIT,  "0 bytes"),
  V(AccountingStart,             STRING,   NULL),
  V(Address,                     STRING,   NULL),
  V(AllowInvalidNodes,           CSV,      "middle,rendezvous"),
  V(AllowNonRFC953Hostnames,     BOOL,     "0"),
  V(AssumeReachable,             BOOL,     "0"),
  V(AuthDirBadExit,              LINELIST, NULL),
  V(AuthDirInvalid,              LINELIST, NULL),
  V(AuthDirReject,               LINELIST, NULL),
  V(AuthDirRejectUnlisted,       BOOL,     "0"),
  V(AuthDirListBadExits,         BOOL,     "0"),
  VAR("AuthoritativeDirectory",  BOOL, AuthoritativeDir,    "0"),
  V(AutomapHostsOnResolve,       BOOL,     "0"),
  V(AutomapHostsSuffixes,        CSV,      ".onion,.exit"),
  V(AvoidDiskWrites,             BOOL,     "0"),
  V(BandwidthBurst,              MEMUNIT,  "6 MB"),
  V(BandwidthRate,               MEMUNIT,  "3 MB"),
  V(BridgeAuthoritativeDir,      BOOL,     "0"),
  VAR("Bridge",                  LINELIST, Bridges,    NULL),
  V(CircuitBuildTimeout,         INTERVAL, "1 minute"),
  V(CircuitIdleTimeout,          INTERVAL, "1 hour"),
  V(ClientDNSRejectInternalAddresses, BOOL,"1"),
  V(ClientOnly,                  BOOL,     "0"),
  V(ConnLimit,                   UINT,     "1000"),
  V(ConstrainedSockets,          BOOL,     "0"),
  V(ConstrainedSockSize,         MEMUNIT,  "8192"),
  V(ContactInfo,                 STRING,   NULL),
  V(ControlListenAddress,        LINELIST, NULL),
  V(ControlPort,                 UINT,     "0"),
  V(ControlSocket,               LINELIST, NULL),
  V(CookieAuthentication,        BOOL,     "0"),
  V(CookieAuthFileGroupReadable, BOOL,     "0"),
  V(CookieAuthFile,              STRING,   NULL),
  V(DataDirectory,               STRING,   NULL),
  OBSOLETE("DebugLogFile"),
  V(DirAllowPrivateAddresses,    BOOL,     NULL),
  V(DirListenAddress,            LINELIST, NULL),
  OBSOLETE("DirFetchPeriod"),
  V(DirPolicy,                   LINELIST, NULL),
  V(DirPort,                     UINT,     "0"),
  OBSOLETE("DirPostPeriod"),
  VAR("DirServer",               LINELIST, DirServers, NULL),
  V(DNSPort,                     UINT,     "0"),
  V(DNSListenAddress,            LINELIST, NULL),
  V(DownloadExtraInfo,           BOOL,     "0"),
  V(EnforceDistinctSubnets,      BOOL,     "1"),
  V(EntryNodes,                  STRING,   NULL),
  V(ExcludeNodes,                STRING,   NULL),
  V(ExitNodes,                   STRING,   NULL),
  V(ExitPolicy,                  LINELIST, NULL),
  V(ExitPolicyRejectPrivate,     BOOL,     "1"),
  V(FascistFirewall,             BOOL,     "0"),
  V(FirewallPorts,               CSV,      ""),
  V(FastFirstHopPK,              BOOL,     "1"),
  V(FetchServerDescriptors,      BOOL,     "1"),
  V(FetchHidServDescriptors,     BOOL,     "1"),
  V(FetchUselessDescriptors,     BOOL,     "0"),
  V(Group,                       STRING,   NULL),
  V(HardwareAccel,               BOOL,     "0"),
  V(HashedControlPassword,       STRING,   NULL),
  VAR("HiddenServiceDir",    LINELIST_S, RendConfigLines,    NULL),
  VAR("HiddenServiceExcludeNodes", LINELIST_S, RendConfigLines, NULL),
  VAR("HiddenServiceNodes",  LINELIST_S, RendConfigLines,    NULL),
  VAR("HiddenServiceOptions",LINELIST_V, RendConfigLines,    NULL),
  VAR("HiddenServicePort",   LINELIST_S, RendConfigLines,    NULL),
  V(HSAuthoritativeDir,          BOOL,     "0"),
  V(HSAuthorityRecordStats,      BOOL,     "0"),
  V(HttpProxy,                   STRING,   NULL),
  V(HttpProxyAuthenticator,      STRING,   NULL),
  V(HttpsProxy,                  STRING,   NULL),
  V(HttpsProxyAuthenticator,     STRING,   NULL),
  OBSOLETE("IgnoreVersion"),
  V(KeepalivePeriod,             INTERVAL, "5 minutes"),
  VAR("Log",                     LINELIST, Logs,             NULL),
  OBSOLETE("LinkPadding"),
  OBSOLETE("LogLevel"),
  OBSOLETE("LogFile"),
  V(LongLivedPorts,              CSV,
                         "21,22,706,1863,5050,5190,5222,5223,6667,6697,8300"),
  VAR("MapAddress",              LINELIST, AddressMap,           NULL),
  V(MaxAdvertisedBandwidth,      MEMUNIT,  "1 GB"),
  V(MaxCircuitDirtiness,         INTERVAL, "10 minutes"),
  V(MaxOnionsPending,            UINT,     "100"),
  OBSOLETE("MonthlyAccountingStart"),
  V(MyFamily,                    STRING,   NULL),
  V(NewCircuitPeriod,            INTERVAL, "30 seconds"),
  VAR("NamingAuthoritativeDirectory",BOOL, NamingAuthoritativeDir, "0"),
  V(NatdListenAddress,           LINELIST, NULL),
  V(NatdPort,                    UINT,     "0"),
  V(Nickname,                    STRING,   NULL),
  V(NoPublish,                   BOOL,     "0"),
  VAR("NodeFamily",              LINELIST, NodeFamilies,         NULL),
  V(NumCpus,                     UINT,     "1"),
  V(NumEntryGuards,              UINT,     "3"),
  V(ORListenAddress,             LINELIST, NULL),
  V(ORPort,                      UINT,     "0"),
  V(OutboundBindAddress,         STRING,   NULL),
  OBSOLETE("PathlenCoinWeight"),
  V(PidFile,                     STRING,   NULL),
  V(PreferTunneledDirConns,      BOOL,     "0"),
  V(ProtocolWarnings,            BOOL,     "0"),
  V(PublishServerDescriptor,     CSV,      "v1,v2"),
  V(PublishHidServDescriptors,   BOOL,     "1"),
  V(ReachableAddresses,          LINELIST, NULL),
  V(ReachableDirAddresses,       LINELIST, NULL),
  V(ReachableORAddresses,        LINELIST, NULL),
  V(RecommendedVersions,         LINELIST, NULL),
  V(RecommendedClientVersions,   LINELIST, NULL),
  V(RecommendedServerVersions,   LINELIST, NULL),
  V(RedirectExit,                LINELIST, NULL),
  V(RelayBandwidthBurst,         MEMUNIT,  "0"),
  V(RelayBandwidthRate,          MEMUNIT,  "0"),
  V(RendExcludeNodes,            STRING,   NULL),
  V(RendNodes,                   STRING,   NULL),
  V(RendPostPeriod,              INTERVAL, "1 hour"),
  V(RephistTrackTime,            INTERVAL, "24 hours"),
  OBSOLETE("RouterFile"),
  V(RunAsDaemon,                 BOOL,     "0"),
  V(RunTesting,                  BOOL,     "0"),
  V(SafeLogging,                 BOOL,     "1"),
  V(SafeSocks,                   BOOL,     "0"),
  V(ServerDNSAllowNonRFC953Hostnames, BOOL,"0"),
  V(ServerDNSDetectHijacking,    BOOL,     "1"),
  V(ServerDNSResolvConfFile,     STRING,   NULL),
  V(ServerDNSSearchDomains,      BOOL,     "0"),
  V(ServerDNSTestAddresses,      CSV,
      "www.google.com,www.mit.edu,www.yahoo.com,www.slashdot.org"),
  V(ShutdownWaitLength,          INTERVAL, "30 seconds"),
  V(SocksListenAddress,          LINELIST, NULL),
  V(SocksPolicy,                 LINELIST, NULL),
  V(SocksPort,                   UINT,     "9050"),
  V(SocksTimeout,                INTERVAL, "2 minutes"),
  OBSOLETE("StatusFetchPeriod"),
  V(StrictEntryNodes,            BOOL,     "0"),
  V(StrictExitNodes,             BOOL,     "0"),
  OBSOLETE("SysLog"),
  V(TestSocks,                   BOOL,     "0"),
  V(TestVia,                     STRING,   NULL),
  V(TrackHostExits,              CSV,      NULL),
  V(TrackHostExitsExpire,        INTERVAL, "30 minutes"),
  OBSOLETE("TrafficShaping"),
  V(TransListenAddress,          LINELIST, NULL),
  V(TransPort,                   UINT,     "0"),
  V(TunnelDirConns,              BOOL,     "0"),
  V(UpdateBridgesFromAuthority,  BOOL,     "0"),
  V(UseBridges,                  BOOL,     "0"),
  V(UseEntryGuards,              BOOL,     "1"),
  V(User,                        STRING,   NULL),
  VAR("V1AuthoritativeDirectory",BOOL, V1AuthoritativeDir,   "0"),
  VAR("V2AuthoritativeDirectory",BOOL, V2AuthoritativeDir,   "0"),
  VAR("V3AuthoritativeDirectory",BOOL, V3AuthoritativeDir,   "0"),
  V(V3AuthVotingInterval,        INTERVAL, "1 hour"),
  V(V3AuthVoteDelay,             INTERVAL, "5 minutes"),
  V(V3AuthDistDelay,             INTERVAL, "5 minutes"),
  V(V3AuthNIntervalsValid,       UINT,     "3"),
  VAR("VersioningAuthoritativeDirectory",BOOL,VersioningAuthoritativeDir, "0"),
  V(VirtualAddrNetwork,          STRING,   "127.192.0.0/10"),
  VAR("__AllDirActionsPrivate",  BOOL,  AllDirActionsPrivate,     "0"),
  VAR("__DisablePredictedCircuits",BOOL,DisablePredictedCircuits, "0"),
  VAR("__LeaveStreamsUnattached",BOOL,  LeaveStreamsUnattached,   "0"),

  { NULL, CONFIG_TYPE_OBSOLETE, 0, NULL }
};
#undef VAR

#define VAR(name,conftype,member,initvalue)                             \
  { name, CONFIG_TYPE_ ## conftype, STRUCT_OFFSET(or_state_t, member),  \
      initvalue }
static config_var_t _state_vars[] = {
  V(AccountingBytesReadInInterval,    MEMUNIT,  NULL),
  V(AccountingBytesWrittenInInterval, MEMUNIT,  NULL),
  V(AccountingExpectedUsage,          MEMUNIT,  NULL),
  V(AccountingIntervalStart,          ISOTIME,  NULL),
  V(AccountingSecondsActive,          INTERVAL, NULL),

  VAR("EntryGuard",              LINELIST_S,  EntryGuards,             NULL),
  VAR("EntryGuardDownSince",     LINELIST_S,  EntryGuards,             NULL),
  VAR("EntryGuardUnlistedSince", LINELIST_S,  EntryGuards,             NULL),
  VAR("EntryGuardAddedBy",       LINELIST_S,  EntryGuards,             NULL),
  V(EntryGuards,                 LINELIST_V,  NULL),

  V(BWHistoryReadEnds,                ISOTIME,  NULL),
  V(BWHistoryReadInterval,            UINT,     "900"),
  V(BWHistoryReadValues,              CSV,      ""),
  V(BWHistoryWriteEnds,               ISOTIME,  NULL),
  V(BWHistoryWriteInterval,           UINT,     "900"),
  V(BWHistoryWriteValues,             CSV,      ""),

  V(TorVersion,                       STRING,   NULL),

  V(LastRotatedOnionKey,              ISOTIME,  NULL),
  V(LastWritten,                      ISOTIME,  NULL),

  { NULL, CONFIG_TYPE_OBSOLETE, 0, NULL }
};

#undef VAR
#undef V
#undef OBSOLETE

/** Represents an English description of a configuration variable; used when
 * generating configuration file comments. */
typedef struct config_var_description_t {
  const char *name;
  const char *description;
} config_var_description_t;

static config_var_description_t options_description[] = {
  /* ==== general options */
  { "AvoidDiskWrites", "If non-zero, try to write to disk less frequently than"
    " we would otherwise." },
  { "BandwidthRate", "A token bucket limits the average incoming bandwidth on "
    "this node to the specified number of bytes per second." },
  { "BandwidthBurst", "Limit the maximum token buffer size (also known as "
    "burst) to the given number of bytes." },
  { "ConnLimit", "Maximum number of simultaneous sockets allowed." },
  { "ConstrainedSockets", "Shrink tx and rx buffers for sockets to avoid "
    "system limits on vservers and related environments.  See man page for "
    "more information regarding this option." },
  { "ConstrainedSockSize", "Limit socket buffers to this size when "
    "ConstrainedSockets is enabled." },
  /*  ControlListenAddress */
  { "ControlPort", "If set, Tor will accept connections from the same machine "
    "(localhost only) on this port, and allow those connections to control "
    "the Tor process using the Tor Control Protocol (described in"
    "control-spec.txt).", },
  { "CookieAuthentication", "If this option is set to 1, don't allow any "
    "connections to the control port except when the connecting process "
    "can read a file that Tor creates in its data directory." },
  { "DataDirectory", "Store working data, state, keys, and caches here." },
  { "DirServer", "Tor only trusts directories signed with one of these "
    "servers' keys.  Used to override the standard list of directory "
    "authorities." },
  /* { "FastFirstHopPK", "" }, */
  /* FetchServerDescriptors, FetchHidServDescriptors,
   * FetchUselessDescriptors */
  { "Group", "On startup, setgid to this group." },
  { "HardwareAccel", "If set, Tor tries to use hardware crypto accelerators "
    "when it can." },
  /* HashedControlPassword */
  { "HTTPProxy", "Force Tor to make all HTTP directory requests through this "
    "host:port (or host:80 if port is not set)." },
  { "HTTPProxyAuthenticator", "A username:password pair to be used with "
    "HTTPProxy." },
  { "HTTPSProxy", "Force Tor to make all TLS (SSL) connectinos through this "
    "host:port (or host:80 if port is not set)." },
  { "HTTPSProxyAuthenticator", "A username:password pair to be used with "
    "HTTPSProxy." },
  { "KeepalivePeriod", "Send a padding cell every N seconds to keep firewalls "
    "from closing our connections while Tor is not in use." },
  { "Log", "Where to send logging messages.  Format is "
    "minSeverity[-maxSeverity] (stderr|stdout|syslog|file FILENAME)." },
  { "OutboundBindAddress", "Make all outbound connections originate from the "
    "provided IP address (only useful for multiple network interfaces)." },
  { "PIDFile", "On startup, write our PID to this file. On clean shutdown, "
    "remove the file." },
  { "PreferTunneledDirConns", "If non-zero, avoid directory servers that "
    "don't support tunneled connections." },
  /* PreferTunneledDirConns */
  /* ProtocolWarnings */
  /* RephistTrackTime */
  { "RunAsDaemon", "If set, Tor forks and daemonizes to the background when "
    "started.  Unix only." },
  { "SafeLogging", "If set to 0, Tor logs potentially sensitive strings "
    "rather than replacing them with the string [scrubbed]." },
  { "TunnelDirConns", "If non-zero, when a directory server we contact "
    "supports it, we will build a one-hop circuit and make an encrypted "
    "connection via its ORPort." },
  { "User", "On startup, setuid to this user" },

  /* ==== client options */
  { "AllowInvalidNodes", "Where on our circuits should Tor allow servers "
    "that the directory authorities haven't called \"valid\"?" },
  { "AllowNonRFC953Hostnames", "If set to 1, we don't automatically reject "
    "hostnames for having invalid characters." },
  /*  CircuitBuildTimeout, CircuitIdleTimeout */
  { "ClientOnly", "If set to 1, Tor will under no circumstances run as a "
    "server, even if ORPort is enabled." },
  { "EntryNodes", "A list of preferred entry nodes to use for the first hop "
    "in circuits, when possible." },
  /* { "EnforceDistinctSubnets" , "" }, */
  { "ExitNodes", "A list of preferred nodes to use for the last hop in "
    "circuits, when possible." },
  { "ExcludeNodes", "A list of nodes never to use when building a circuit." },
  { "FascistFirewall", "If set, Tor will only create outgoing connections to "
    "servers running on the ports listed in FirewallPorts." },
  { "FirewallPorts", "A list of ports that we can connect to.  Only used "
    "when FascistFirewall is set." },
  { "LongLivedPorts", "A list of ports for services that tend to require "
    "high-uptime connections." },
  { "MapAddress", "Force Tor to treat all requests for one address as if "
    "they were for another." },
  { "NewCircuitPeriod", "Force Tor to consider whether to build a new circuit "
    "every NUM seconds." },
  { "MaxCircuitDirtiness", "Do not attach new streams to a circuit that has "
    "been used more than this many seconds ago." },
  /* NatdPort, NatdListenAddress */
  { "NodeFamily", "A list of servers that constitute a 'family' and should "
    "never be used in the same circuit." },
  { "NumEntryGuards", "How many entry guards should we keep at a time?" },
  /* PathlenCoinWeight */
  { "ReachableAddresses", "Addresses we can connect to, as IP/bits:port-port. "
    "By default, we assume all addresses are reachable." },
  /* reachablediraddresses, reachableoraddresses. */
  { "RendNodes", "A list of preferred nodes to use for a rendezvous point, "
    "when possible." },
  { "RendExcludenodes", "A list of nodes never to use as rendezvous points." },
  /* SafeSOCKS */
  { "SOCKSPort", "The port where we listen for SOCKS connections from "
    "applications." },
  { "SOCKSListenAddress", "Bind to this address to listen to connections from "
    "SOCKS-speaking applications." },
  { "SOCKSPolicy", "Set an entry policy to limit which addresses can connect "
    "to the SOCKSPort." },
  /* SocksTimeout */
  { "StrictExitNodes", "If set, Tor will fail to operate when none of the "
    "configured ExitNodes can be used." },
  { "StrictEntryNodes", "If set, Tor will fail to operate when none of the "
    "configured EntryNodes can be used." },
  /* TestSocks */
  { "TrackHostsExit", "Hosts and domains which should, if possible, be "
    "accessed from the same exit node each time we connect to them." },
  { "TrackHostsExitExpire", "Time after which we forget which exit we were "
    "using to connect to hosts in TrackHostsExit." },
  /* "TransPort", "TransListenAddress */
  { "UseEntryGuards", "Set to 0 if we want to pick from the whole set of "
    "servers for the first position in each circuit, rather than picking a "
    "set of 'Guards' to prevent profiling attacks." },

  /* === server options */
  { "Address", "The advertised (external) address we should use." },
  /* Accounting* options. */
  /* AssumeReachable */
  { "ContactInfo", "Administrative contact information to advertise for this "
    "server." },
  { "ExitPolicy", "Address/port ranges for which to accept or reject outgoing "
    "connections on behalf of Tor users." },
  /*  { "ExitPolicyRejectPrivate, "" }, */
  { "MaxAdvertisedBandwidth", "If set, we will not advertise more than this "
    "amount of bandwidth for our bandwidth rate, regardless of how much "
    "bandwidth we actually detect." },
  { "MaxOnionsPending", "Reject new attempts to extend circuits when we "
    "already have this many pending." },
  { "MyFamily", "Declare a list of other servers as belonging to the same "
    "family as this one, so that clients will not use two from the same "
    "family in the same circuit." },
  { "Nickname", "Set the server nickname." },
  { "NoPublish", "{DEPRECATED}" },
  { "NumCPUs", "How many processes to use at once for public-key crypto." },
  { "ORPort", "Advertise this port to listen for connections from Tor clients "
    "and servers." },
  { "ORListenAddress", "Bind to this address to listen for connections from "
    "clients and servers, instead of the default 0.0.0.0:ORPort." },
  { "PublishServerDescriptor", "Set to \"\" to keep the server from "
    "uploading info to the directory authorities." },
  /*{ "RedirectExit", "When an outgoing connection tries to connect to a "
   *"given address, redirect it to another address instead." },
   */
  /* ServerDNS: DetectHijacking, ResolvConfFile, SearchDomains */
  { "ShutdownWaitLength", "Wait this long for clients to finish when "
    "shutting down because of a SIGINT." },
  /* { "TestVia", } */

  /* === directory cache options */
  { "DirPort", "Serve directory information from this port, and act as a "
    "directory cache." },
  { "DirListenAddress", "Bind to this address to listen for connections from "
    "clients and servers, instead of the default 0.0.0.0:DirPort." },
  { "DirPolicy", "Set a policy to limit who can connect to the directory "
    "port" },

  /*  Authority options: AuthDirBadExit, AuthDirInvalid, AuthDirReject,
   * AuthDirRejectUnlisted, AuthDirListBadExits, AuthoritativeDirectory,
   * DirAllowPrivateAddresses, HSAuthoritativeDir,
   * NamingAuthoritativeDirectory, RecommendedVersions,
   * RecommendedClientVersions, RecommendedServerVersions, RendPostPeriod,
   * RunTesting, V1AuthoritativeDirectory, VersioningAuthoritativeDirectory, */

  /* Hidden service options: HiddenService: dir,excludenodes, nodes,
   * options, port.  PublishHidServDescriptor */

  /* Nonpersistent options: __LeaveStreamsUnattached, __AllDirActionsPrivate */
  { NULL, NULL },
};

static config_var_description_t state_description[] = {
  { "AccountingBytesReadInInterval",
    "How many bytes have we read in this accounting period?" },
  { "AccountingBytesWrittenInInterval",
    "How many bytes have we written in this accounting period?" },
  { "AccountingExpectedUsage",
    "How many bytes did we expect to use per minute? (0 for no estimate.)" },
  { "AccountingIntervalStart", "When did this accounting period begin?" },
  { "AccountingSecondsActive", "How long have we been awake in this period?" },

  { "BWHistoryReadEnds", "When does the last-recorded read-interval end?" },
  { "BWHistoryReadInterval", "How long is each read-interval (in seconds)?" },
  { "BWHistoryReadValues", "Number of bytes read in each interval." },
  { "BWHistoryWriteEnds", "When does the last-recorded write-interval end?" },
  { "BWHistoryWriteInterval", "How long is each write-interval (in seconds)?"},
  { "BWHistoryWriteValues", "Number of bytes written in each interval." },

  { "EntryGuard", "One of the nodes we have chosen as a fixed entry" },
  { "EntryGuardDownSince",
    "The last entry guard has been unreachable since this time." },
  { "EntryGuardUnlistedSince",
    "The last entry guard has been unusable since this time." },

  { "LastRotatedOnionKey",
    "The last time at which we changed the medium-term private key used for "
    "building circuits." },
  { "LastWritten", "When was this state file last regenerated?" },

  { "TorVersion", "Which version of Tor generated this state file?" },
  { NULL, NULL },
};

/** Type of a callback to validate whether a given configuration is
 * well-formed and consistent. See options_trial_assign() for documentation
 * of arguments. */
typedef int (*validate_fn_t)(void*,void*,int,char**);

/** Information on the keys, value types, key-to-struct-member mappings,
 * variable descriptions, validation functions, and abbreviations for a
 * configuration or storage format. */
typedef struct {
  size_t size; /**< Size of the struct that everything gets parsed into. */
  uint32_t magic; /**< Required 'magic value' to make sure we have a struct
                   * of the right type. */
  off_t magic_offset; /**< Offset of the magic value within the struct. */
  config_abbrev_t *abbrevs; /**< List of abbreviations that we expand when
                             * parsing this format. */
  config_var_t *vars; /**< List of variables we recognize, their default
                       * values, and where we stick them in the structure. */
  validate_fn_t validate_fn; /**< Function to validate config. */
  /** Documentation for configuration variables. */
  config_var_description_t *descriptions;
  /** If present, extra is a LINELIST variable for unrecognized
   * lines.  Otherwise, unrecognized lines are an error. */
  config_var_t *extra;
} config_format_t;

/** Macro: assert that <b>cfg</b> has the right magic field for format
 * <b>fmt</b>. */
#define CHECK(fmt, cfg) STMT_BEGIN                                      \
    tor_assert(fmt && cfg);                                             \
    tor_assert((fmt)->magic ==                                          \
               *(uint32_t*)STRUCT_VAR_P(cfg,fmt->magic_offset));        \
  STMT_END

static void config_line_append(config_line_t **lst,
                               const char *key, const char *val);
static void option_clear(config_format_t *fmt, or_options_t *options,
                         config_var_t *var);
static void option_reset(config_format_t *fmt, or_options_t *options,
                         config_var_t *var, int use_defaults);
static void config_free(config_format_t *fmt, void *options);
static int option_is_same(config_format_t *fmt,
                          or_options_t *o1, or_options_t *o2,
                          const char *name);
static or_options_t *options_dup(config_format_t *fmt, or_options_t *old);
static int options_validate(or_options_t *old_options, or_options_t *options,
                            int from_setconf, char **msg);
static int options_act_reversible(or_options_t *old_options, char **msg);
static int options_act(or_options_t *old_options);
static int options_transition_allowed(or_options_t *old, or_options_t *new,
                                      char **msg);
static int options_transition_affects_workers(or_options_t *old_options,
                                              or_options_t *new_options);
static int options_transition_affects_descriptor(or_options_t *old_options,
                                                 or_options_t *new_options);
static int check_nickname_list(const char *lst, const char *name, char **msg);
static void config_register_addressmaps(or_options_t *options);

static int parse_bridge_line(const char *line, int validate_only);
static int parse_dir_server_line(const char *line, int validate_only);
static int parse_redirect_line(smartlist_t *result,
                               config_line_t *line, char **msg);
static int parse_log_severity_range(const char *range, int *min_out,
                                    int *max_out);
static int validate_data_directory(or_options_t *options);
static int write_configuration_file(const char *fname, or_options_t *options);
static config_line_t *get_assigned_option(config_format_t *fmt,
                                     or_options_t *options, const char *key);
static void config_init(config_format_t *fmt, void *options);
static int or_state_validate(or_state_t *old_options, or_state_t *options,
                             int from_setconf, char **msg);
static int or_state_load(void);
static int options_init_logs(or_options_t *options, int validate_only);

static uint64_t config_parse_memunit(const char *s, int *ok);
static int config_parse_interval(const char *s, int *ok);
static void print_svn_version(void);
static void init_libevent(void);
static int opt_streq(const char *s1, const char *s2);
/** Versions of libevent. */
typedef enum {
  /* Note: we compare these, so it's important that "old" precede everything,
   * and that "other" come last. */
  LE_OLD=0, LE_10C, LE_10D, LE_10E, LE_11, LE_11A, LE_11B, LE_12, LE_12A,
  LE_13, LE_13A, LE_13B, LE_13C, LE_13D,
  LE_OTHER
} le_version_t;
static le_version_t decode_libevent_version(void);
#if defined(HAVE_EVENT_GET_VERSION) && defined(HAVE_EVENT_GET_METHOD)
static void check_libevent_version(const char *m, int server);
#endif

/** Magic value for or_options_t. */
#define OR_OPTIONS_MAGIC 9090909

/** Configuration format for or_options_t. */
static config_format_t options_format = {
  sizeof(or_options_t),
  OR_OPTIONS_MAGIC,
  STRUCT_OFFSET(or_options_t, _magic),
  _option_abbrevs,
  _option_vars,
  (validate_fn_t)options_validate,
  options_description,
  NULL
};

/** Magic value for or_state_t. */
#define OR_STATE_MAGIC 0x57A73f57

/** "Extra" variable in the state that receives lines we can't parse. This
 * lets us preserve options from versions of Tor newer than us. */
static config_var_t state_extra_var = {
  "__extra", CONFIG_TYPE_LINELIST, STRUCT_OFFSET(or_state_t, ExtraLines), NULL
};

/** Configuration format for or_state_t. */
static config_format_t state_format = {
  sizeof(or_state_t),
  OR_STATE_MAGIC,
  STRUCT_OFFSET(or_state_t, _magic),
  _state_abbrevs,
  _state_vars,
  (validate_fn_t)or_state_validate,
  state_description,
  &state_extra_var,
};

/*
 * Functions to read and write the global options pointer.
 */

/** Command-line and config-file options. */
static or_options_t *global_options = NULL;
/** Name of most recently read torrc file. */
static char *torrc_fname = NULL;
/** Persistent serialized state. */
static or_state_t *global_state = NULL;

/** Allocate an empty configuration object of a given format type. */
static void *
config_alloc(config_format_t *fmt)
{
  void *opts = tor_malloc_zero(fmt->size);
  *(uint32_t*)STRUCT_VAR_P(opts, fmt->magic_offset) = fmt->magic;
  CHECK(fmt, opts);
  return opts;
}

/** Return the currently configured options. */
or_options_t *
get_options(void)
{
  tor_assert(global_options);
  return global_options;
}

/** Change the current global options to contain <b>new_val</b> instead of
 * their current value; take action based on the new value; free the old value
 * as necessary.
 */
int
set_options(or_options_t *new_val, char **msg)
{
  or_options_t *old_options = global_options;
  global_options = new_val;
  /* Note that we pass the *old* options below, for comparison. It
   * pulls the new options directly out of global_options. */
  if (options_act_reversible(old_options, msg)<0) {
    tor_assert(*msg);
    global_options = old_options;
    return -1;
  }
  if (options_act(old_options) < 0) { /* acting on the options failed. die. */
    log_err(LD_BUG,
            "Acting on config options left us in a broken state. Dying.");
    exit(1);
  }
  if (old_options)
    config_free(&options_format, old_options);

  return 0;
}

extern const char tor_svn_revision[]; /* from tor_main.c */

static char *_version = NULL;

/** Return the current Tor version, possibly */
const char *
get_version(void)
{
  if (_version == NULL) {
    if (strlen(tor_svn_revision)) {
      size_t len = strlen(VERSION)+strlen(tor_svn_revision)+8;
      _version = tor_malloc(len);
      tor_snprintf(_version, len, "%s (r%s)", VERSION, tor_svn_revision);
    } else {
      _version = tor_strdup(VERSION);
    }
  }
  return _version;
}

/** Release all memory and resources held by global configuration structures.
 */
void
config_free_all(void)
{
  if (global_options) {
    config_free(&options_format, global_options);
    global_options = NULL;
  }
  if (global_state) {
    config_free(&state_format, global_state);
    global_state = NULL;
  }
  tor_free(torrc_fname);
  tor_free(_version);
}

/** If options->SafeLogging is on, return a not very useful string,
 * else return address.
 */
const char *
safe_str(const char *address)
{
  tor_assert(address);
  if (get_options()->SafeLogging)
    return "[scrubbed]";
  else
    return address;
}

/** Equivalent to escaped(safe_str(address)).  See reentrancy note on
 * escaped(): don't use this outside the main thread, or twice in the same
 * log statement. */
const char *
escaped_safe_str(const char *address)
{
  if (get_options()->SafeLogging)
    return "[scrubbed]";
  else
    return escaped(address);
}

/** Add the default directory servers directly into the trusted dir list. */
static void
add_default_trusted_dirservers(void)
{
  int i;
  const char *dirservers[] = {
    "moria1 v1 orport=9001 v3ident=5420FD8EA46BD4290F1D07A1883C9D85ECC486C4 "
      "128.31.0.34:9031 FFCB 46DB 1339 DA84 674C 70D7 CB58 6434 C437 0441",
    "moria2 v1 orport=9002 128.31.0.34:9032 "
      "719B E45D E224 B607 C537 07D0 E214 3E2D 423E 74CF",
    "tor26 v1 orport=443 v3ident=A9AC67E64B200BBF2FA26DF194AC0469E2A948C6 "
      "86.59.21.38:80 847B 1F85 0344 D787 6491 A548 92F9 0493 4E4E B85D",
    "lefkada orport=443 140.247.60.64:80 "
      "38D4 F5FC F7B1 0232 28B8 95EA 56ED E7D5 CCDC AF32",
    "dizum 194.109.206.212:80 "
      "7EA6 EAD6 FD83 083C 538F 4403 8BBF A077 587D D755",
    "Tonga orport=443 bridge no-v2 82.94.251.206:80 "
      "4A0C CD2D DC79 9508 3D73 F5D6 6710 0C8A 5831 F16D",
    NULL
  };
  for (i=0; dirservers[i]; i++)
    parse_dir_server_line(dirservers[i], 0);
}

/** Fetch the active option list, and take actions based on it. All of the
 * things we do should survive being done repeatedly.  If present,
 * <b>old_options</b> contains the previous value of the options.
 *
 * Return 0 if all goes well, return -1 if things went badly.
 */
static int
options_act_reversible(or_options_t *old_options, char **msg)
{
  smartlist_t *new_listeners = smartlist_create();
  smartlist_t *replaced_listeners = smartlist_create();
  static int libevent_initialized = 0;
  or_options_t *options = get_options();
  int running_tor = options->command == CMD_RUN_TOR;
  int set_conn_limit = 0;
  int r = -1;
  int logs_marked = 0;

  /* Daemonize _first_, since we only want to open most of this stuff in
   * the subprocess.  Libevent bases can't be reliably inherited across
   * processes. */
  if (running_tor && options->RunAsDaemon) {
    /* No need to roll back, since you can't change the value. */
    start_daemon();
  }

#ifndef HAVE_SYS_UN_H
  if (options->ControlSocket) {
    *msg = tor_strdup("Unix domain sockets (ControlSocket) not supported"
                      " on this OS/with this build.");
    goto rollback;
  }
#endif

  if (running_tor) {
    /* We need to set the connection limit before we can open the listeners. */
    options->_ConnLimit =
      set_max_file_descriptors((unsigned)options->ConnLimit, MAXCONNECTIONS);
    if (options->_ConnLimit < 0) {
      *msg = tor_strdup("Problem with ConnLimit value. See logs for details.");
      goto rollback;
    }
    set_conn_limit = 1;

    /* Set up libevent.  (We need to do this before we can register the
     * listeners as listeners.) */
    if (running_tor && !libevent_initialized) {
      init_libevent();
      libevent_initialized = 1;
    }

    /* Launch the listeners.  (We do this before we setuid, so we can bind to
     * ports under 1024.) */
    if (retry_all_listeners(replaced_listeners, new_listeners) < 0) {
      *msg = tor_strdup("Failed to bind one of the listener ports.");
      goto rollback;
    }
  }

  /* Setuid/setgid as appropriate */
  if (options->User || options->Group) {
    if (switch_id(options->User, options->Group) != 0) {
      /* No need to roll back, since you can't change the value. */
      *msg = tor_strdup("Problem with User or Group value. "
                        "See logs for details.");
      goto done;
    }
  }

  /* Ensure data directory is private; create if possible. */
  if (check_private_dir(options->DataDirectory, CPD_CREATE)<0) {
    char buf[1024];
    int tmp = tor_snprintf(buf, sizeof(buf),
              "Couldn't access/create private data directory \"%s\"",
              options->DataDirectory);
    *msg = tor_strdup(tmp >= 0 ? buf : "internal error");
    goto done;
    /* No need to roll back, since you can't change the value. */
  }

  /* Bail out at this point if we're not going to be a client or server:
   * we don't run Tor itself. */
  if (!running_tor)
    goto commit;

  mark_logs_temp(); /* Close current logs once new logs are open. */
  logs_marked = 1;
  if (options_init_logs(options, 0)<0) { /* Configure the log(s) */
    *msg = tor_strdup("Failed to init Log options. See logs for details.");
    goto rollback;
  }

 commit:
  r = 0;
  if (logs_marked) {
    close_temp_logs();
    add_callback_log(LOG_ERR, LOG_ERR, control_event_logmsg);
    control_adjust_event_log_severity();
  }
  SMARTLIST_FOREACH(replaced_listeners, connection_t *, conn,
  {
    log_notice(LD_NET, "Closing old %s on %s:%d",
               conn_type_to_string(conn->type), conn->address, conn->port);
    connection_close_immediate(conn);
    connection_mark_for_close(conn);
  });
  goto done;

 rollback:
  r = -1;
  tor_assert(*msg);

  if (logs_marked) {
    rollback_log_changes();
    control_adjust_event_log_severity();
  }

  if (set_conn_limit && old_options)
    set_max_file_descriptors((unsigned)old_options->ConnLimit,MAXCONNECTIONS);

  SMARTLIST_FOREACH(new_listeners, connection_t *, conn,
  {
    log_notice(LD_NET, "Closing partially-constructed listener %s on %s:%d",
               conn_type_to_string(conn->type), conn->address, conn->port);
    connection_close_immediate(conn);
    connection_mark_for_close(conn);
  });

 done:
  smartlist_free(new_listeners);
  smartlist_free(replaced_listeners);
  return r;
}

/** Fetch the active option list, and take actions based on it. All of the
 * things we do should survive being done repeatedly.  If present,
 * <b>old_options</b> contains the previous value of the options.
 *
 * Return 0 if all goes well, return -1 if it's time to die.
 *
 * Note: We haven't moved all the "act on new configuration" logic
 * here yet.  Some is still in do_hup() and other places.
 */
static int
options_act(or_options_t *old_options)
{
  config_line_t *cl;
  char *fn;
  size_t len;
  or_options_t *options = get_options();
  int running_tor = options->command == CMD_RUN_TOR;
  char *msg;

  if (options->DirServers) {
    clear_trusted_dir_servers();
    for (cl = options->DirServers; cl; cl = cl->next) {
      if (parse_dir_server_line(cl->value, 0)<0) {
        log_warn(LD_BUG,
                 "Previously validated DirServer line could not be added!");
        return -1;
      }
    }
  } else {
    if (!smartlist_len(router_get_trusted_dir_servers()))
      add_default_trusted_dirservers();
  }

  clear_bridge_list();
  if (options->Bridges) {
    for (cl = options->Bridges; cl; cl = cl->next) {
      if (parse_bridge_line(cl->value, 0)<0) {
        log_warn(LD_BUG,
                 "Previously validated Bridge line could not be added!");
        return -1;
      }
    }
  }

  if (running_tor && rend_config_services(options, 0)<0) {
    log_warn(LD_BUG,
       "Previously validated hidden services line could not be added!");
    return -1;
  }

  if (running_tor) {
    len = strlen(options->DataDirectory)+32;
    fn = tor_malloc(len);
    tor_snprintf(fn, len, "%s"PATH_SEPARATOR"cached-status",
                 options->DataDirectory);
    if (check_private_dir(fn, CPD_CREATE) != 0) {
      log_warn(LD_CONFIG,
               "Couldn't access/create private data directory \"%s\"", fn);
      tor_free(fn);
      return -1;
    }
    tor_free(fn);
  }

  /* Load state */
  if (! global_state && options->command == CMD_RUN_TOR) {
    if (or_state_load())
      return -1;
    rep_hist_load_mtbf_data(time(NULL));
  }

  /* Bail out at this point if we're not going to be a client or server:
   * we want to not fork, and to log stuff to stderr. */
  if (options->command != CMD_RUN_TOR)
    return 0;

  {
    smartlist_t *sl = smartlist_create();
    char *errmsg = NULL;
    for (cl = options->RedirectExit; cl; cl = cl->next) {
      if (parse_redirect_line(sl, cl, &errmsg)<0) {
        log_warn(LD_CONFIG, "%s", errmsg);
        tor_free(errmsg);
        return -1;
      }
    }
    set_exit_redirects(sl);
  }

  /* Finish backgrounding the process */
  if (running_tor && options->RunAsDaemon) {
    /* We may be calling this for the n'th time (on SIGHUP), but it's safe. */
    finish_daemon(options->DataDirectory);
  }

  /* Write our pid to the pid file. If we do not have write permissions we
   * will log a warning */
  if (running_tor && options->PidFile)
    write_pidfile(options->PidFile);

  /* Register addressmap directives */
  config_register_addressmaps(options);
  parse_virtual_addr_network(options->VirtualAddrNetwork, 0, &msg);

  /* Update address policies. */
  policies_parse_from_options(options);

  if (init_cookie_authentication(options->CookieAuthentication) < 0) {
    log_warn(LD_CONFIG,"Error creating cookie authentication file.");
    return -1;
  }

  /* reload keys as needed for rendezvous services. */
  if (rend_service_load_keys()<0) {
    log_warn(LD_GENERAL,"Error loading rendezvous service keys");
    return -1;
  }

  /* Set up accounting */
  if (accounting_parse_options(options, 0)<0) {
    log_warn(LD_CONFIG,"Error in accounting options");
    return -1;
  }
  if (accounting_is_enabled(options))
    configure_accounting(time(NULL));

  if (!running_tor)
    return 0;

  /* Check for transitions that need action. */
  if (old_options) {
    if (options->UseEntryGuards && !old_options->UseEntryGuards) {
      log_info(LD_CIRC,
               "Switching to entry guards; abandoning previous circuits");
      circuit_mark_all_unused_circs();
      circuit_expire_all_dirty_circs();
    }

    if (options_transition_affects_workers(old_options, options)) {
      log_info(LD_GENERAL,
               "Worker-related options changed. Rotating workers.");
      if (server_mode(options) && !server_mode(old_options)) {
        if (init_keys() < 0) {
          log_warn(LD_BUG,"Error initializing keys; exiting");
          return -1;
        }
        ip_address_changed(0);
        if (has_completed_circuit || !any_predicted_circuits(time(NULL)))
          inform_testing_reachability();
      }
      cpuworkers_rotate();
      if (dns_reset())
        return -1;
    } else {
      if (dns_reset())
        return -1;
    }

    if (options->V3AuthoritativeDir && !old_options->V3AuthoritativeDir)
      init_keys();
  }

  /* Check if we need to parse and add the EntryNodes config option. */
  if (options->EntryNodes &&
      (!old_options ||
       !opt_streq(old_options->EntryNodes, options->EntryNodes)))
    entry_nodes_should_be_added();

  /* Since our options changed, we might need to regenerate and upload our
   * server descriptor.
   */
  if (!old_options ||
      options_transition_affects_descriptor(old_options, options))
    mark_my_descriptor_dirty();

  return 0;
}

/*
 * Functions to parse config options
 */

/** If <b>option</b> is an official abbreviation for a longer option,
 * return the longer option.  Otherwise return <b>option</b>.
 * If <b>command_line</b> is set, apply all abbreviations.  Otherwise, only
 * apply abbreviations that work for the config file and the command line.
 * If <b>warn_obsolete</b> is set, warn about deprecated names. */
static const char *
expand_abbrev(config_format_t *fmt, const char *option, int command_line,
              int warn_obsolete)
{
  int i;
  if (! fmt->abbrevs)
    return option;
  for (i=0; fmt->abbrevs[i].abbreviated; ++i) {
    /* Abbreviations are casei. */
    if (!strcasecmp(option,fmt->abbrevs[i].abbreviated) &&
        (command_line || !fmt->abbrevs[i].commandline_only)) {
      if (warn_obsolete && fmt->abbrevs[i].warn) {
        log_warn(LD_CONFIG,
                 "The configuration option '%s' is deprecated; "
                 "use '%s' instead.",
                 fmt->abbrevs[i].abbreviated,
                 fmt->abbrevs[i].full);
      }
      return fmt->abbrevs[i].full;
    }
  }
  return option;
}

/** Helper: Read a list of configuration options from the command line.
 * If successful, put them in *<b>result</b> and return 0, and return
 * -1 and leave *<b>result</b> alone. */
static int
config_get_commandlines(int argc, char **argv, config_line_t **result)
{
  config_line_t *front = NULL;
  config_line_t **new = &front;
  char *s;
  int i = 1;

  while (i < argc) {
    if (!strcmp(argv[i],"-f") ||
        !strcmp(argv[i],"--hash-password")) {
      i += 2; /* command-line option with argument. ignore them. */
      continue;
    } else if (!strcmp(argv[i],"--list-fingerprint") ||
               !strcmp(argv[i],"--verify-config") ||
               !strcmp(argv[i],"--ignore-missing-torrc")) {
      i += 1; /* command-line option. ignore it. */
      continue;
    } else if (!strcmp(argv[i],"--nt-service") ||
               !strcmp(argv[i],"-nt-service")) {
      i += 1;
      continue;
    }
    if (i == argc-1) {
      log_warn(LD_CONFIG,"Command-line option '%s' with no value. Failing.",
               argv[i]);
      config_free_lines(front);
      return -1;
    }

    *new = tor_malloc_zero(sizeof(config_line_t));
    s = argv[i];

    while (*s == '-')
      s++;

    (*new)->key = tor_strdup(expand_abbrev(&options_format, s, 1, 1));
    (*new)->value = tor_strdup(argv[i+1]);
    (*new)->next = NULL;
    log(LOG_DEBUG, LD_CONFIG, "Commandline: parsed keyword '%s', value '%s'",
        (*new)->key, (*new)->value);

    new = &((*new)->next);
    i += 2;
  }
  *result = front;
  return 0;
}

/** Helper: allocate a new configuration option mapping 'key' to 'val',
 * append it to *<b>lst</b>. */
static void
config_line_append(config_line_t **lst,
                   const char *key,
                   const char *val)
{
  config_line_t *newline;

  newline = tor_malloc(sizeof(config_line_t));
  newline->key = tor_strdup(key);
  newline->value = tor_strdup(val);
  newline->next = NULL;
  while (*lst)
    lst = &((*lst)->next);

  (*lst) = newline;
}

/** Helper: parse the config string and strdup into key/value
 * strings. Set *result to the list, or NULL if parsing the string
 * failed.  Return 0 on success, -1 on failure. Warn and ignore any
 * misformatted lines. Modifies the contents of <b>string</b>. */
int
config_get_lines(char *string, config_line_t **result)
{
  config_line_t *list = NULL, **next;
  char *k, *v;

  next = &list;
  do {
    string = parse_line_from_str(string, &k, &v);
    if (!string) {
      config_free_lines(list);
      return -1;
    }
    if (k && v) {
      /* This list can get long, so we keep a pointer to the end of it
       * rather than using config_line_append over and over and getting n^2
       * performance.  This is the only really long list. */
      *next = tor_malloc(sizeof(config_line_t));
      (*next)->key = tor_strdup(k);
      (*next)->value = tor_strdup(v);
      (*next)->next = NULL;
      next = &((*next)->next);
    }
  } while (*string);

  *result = list;
  return 0;
}

/**
 * Free all the configuration lines on the linked list <b>front</b>.
 */
void
config_free_lines(config_line_t *front)
{
  config_line_t *tmp;

  while (front) {
    tmp = front;
    front = tmp->next;

    tor_free(tmp->key);
    tor_free(tmp->value);
    tor_free(tmp);
  }
}

/** Return the description for a given configuration variable, or NULL if no
 * description exists. */
static const char *
config_find_description(config_format_t *fmt, const char *name)
{
  int i;
  for (i=0; fmt->descriptions[i].name; ++i) {
    if (!strcasecmp(name, fmt->descriptions[i].name))
      return fmt->descriptions[i].description;
  }
  return NULL;
}

/** If <b>key</b> is a configuration option, return the corresponding
 * config_var_t.  Otherwise, if <b>key</b> is a non-standard abbreviation,
 * warn, and return the corresponding config_var_t.  Otherwise return NULL.
 */
static config_var_t *
config_find_option(config_format_t *fmt, const char *key)
{
  int i;
  size_t keylen = strlen(key);
  if (!keylen)
    return NULL; /* if they say "--" on the commandline, it's not an option */
  /* First, check for an exact (case-insensitive) match */
  for (i=0; fmt->vars[i].name; ++i) {
    if (!strcasecmp(key, fmt->vars[i].name)) {
      return &fmt->vars[i];
    }
  }
  /* If none, check for an abbreviated match */
  for (i=0; fmt->vars[i].name; ++i) {
    if (!strncasecmp(key, fmt->vars[i].name, keylen)) {
      log_warn(LD_CONFIG, "The abbreviation '%s' is deprecated. "
               "Please use '%s' instead",
               key, fmt->vars[i].name);
      return &fmt->vars[i];
    }
  }
  /* Okay, unrecognized option */
  return NULL;
}

/*
 * Functions to assign config options.
 */

/** <b>c</b>-\>key is known to be a real key. Update <b>options</b>
 * with <b>c</b>-\>value and return 0, or return -1 if bad value.
 *
 * Called from config_assign_line() and option_reset().
 */
static int
config_assign_value(config_format_t *fmt, or_options_t *options,
                    config_line_t *c, char **msg)
{
  int i, r, ok;
  char buf[1024];
  config_var_t *var;
  void *lvalue;

  CHECK(fmt, options);

  var = config_find_option(fmt, c->key);
  tor_assert(var);

  lvalue = STRUCT_VAR_P(options, var->var_offset);

  switch (var->type) {

  case CONFIG_TYPE_UINT:
    i = tor_parse_long(c->value, 10, 0, INT_MAX, &ok, NULL);
    if (!ok) {
      r = tor_snprintf(buf, sizeof(buf),
          "Int keyword '%s %s' is malformed or out of bounds.",
          c->key, c->value);
      *msg = tor_strdup(r >= 0 ? buf : "internal error");
      return -1;
    }
    *(int *)lvalue = i;
    break;

  case CONFIG_TYPE_INTERVAL: {
    i = config_parse_interval(c->value, &ok);
    if (!ok) {
      r = tor_snprintf(buf, sizeof(buf),
          "Interval '%s %s' is malformed or out of bounds.",
          c->key, c->value);
      *msg = tor_strdup(r >= 0 ? buf : "internal error");
      return -1;
    }
    *(int *)lvalue = i;
    break;
  }

  case CONFIG_TYPE_MEMUNIT: {
    uint64_t u64 = config_parse_memunit(c->value, &ok);
    if (!ok) {
      r = tor_snprintf(buf, sizeof(buf),
          "Value '%s %s' is malformed or out of bounds.",
          c->key, c->value);
      *msg = tor_strdup(r >= 0 ? buf : "internal error");
      return -1;
    }
    *(uint64_t *)lvalue = u64;
    break;
  }

  case CONFIG_TYPE_BOOL:
    i = tor_parse_long(c->value, 10, 0, 1, &ok, NULL);
    if (!ok) {
      r = tor_snprintf(buf, sizeof(buf),
          "Boolean '%s %s' expects 0 or 1.",
          c->key, c->value);
      *msg = tor_strdup(r >= 0 ? buf : "internal error");
      return -1;
    }
    *(int *)lvalue = i;
    break;

  case CONFIG_TYPE_STRING:
    tor_free(*(char **)lvalue);
    *(char **)lvalue = tor_strdup(c->value);
    break;

  case CONFIG_TYPE_DOUBLE:
    *(double *)lvalue = atof(c->value);
    break;

  case CONFIG_TYPE_ISOTIME:
    if (parse_iso_time(c->value, (time_t *)lvalue)) {
      r = tor_snprintf(buf, sizeof(buf),
          "Invalid time '%s' for keyword '%s'", c->value, c->key);
      *msg = tor_strdup(r >= 0 ? buf : "internal error");
      return -1;
    }
    break;

  case CONFIG_TYPE_CSV:
    if (*(smartlist_t**)lvalue) {
      SMARTLIST_FOREACH(*(smartlist_t**)lvalue, char *, cp, tor_free(cp));
      smartlist_clear(*(smartlist_t**)lvalue);
    } else {
      *(smartlist_t**)lvalue = smartlist_create();
    }

    smartlist_split_string(*(smartlist_t**)lvalue, c->value, ",",
                           SPLIT_SKIP_SPACE|SPLIT_IGNORE_BLANK, 0);
    break;

  case CONFIG_TYPE_LINELIST:
  case CONFIG_TYPE_LINELIST_S:
    config_line_append((config_line_t**)lvalue, c->key, c->value);
    break;

  case CONFIG_TYPE_OBSOLETE:
    log_warn(LD_CONFIG, "Skipping obsolete configuration option '%s'", c->key);
    break;
  case CONFIG_TYPE_LINELIST_V:
    r = tor_snprintf(buf, sizeof(buf),
        "You may not provide a value for virtual option '%s'", c->key);
    *msg = tor_strdup(r >= 0 ? buf : "internal error");
    return -1;
  default:
    tor_assert(0);
    break;
  }
  return 0;
}

/** If <b>c</b> is a syntactically valid configuration line, update
 * <b>options</b> with its value and return 0.  Otherwise return -1 for bad
 * key, -2 for bad value.
 *
 * If <b>clear_first</b> is set, clear the value first. Then if
 * <b>use_defaults</b> is set, set the value to the default.
 *
 * Called from config_assign().
 */
static int
config_assign_line(config_format_t *fmt, or_options_t *options,
                   config_line_t *c, int use_defaults,
                   int clear_first, char **msg)
{
  config_var_t *var;

  CHECK(fmt, options);

  var = config_find_option(fmt, c->key);
  if (!var) {
    if (fmt->extra) {
      void *lvalue = STRUCT_VAR_P(options, fmt->extra->var_offset);
      log_info(LD_CONFIG,
               "Found unrecognized option '%s'; saving it.", c->key);
      config_line_append((config_line_t**)lvalue, c->key, c->value);
      return 0;
    } else {
      char buf[1024];
      int tmp = tor_snprintf(buf, sizeof(buf),
                "Unknown option '%s'.  Failing.", c->key);
      *msg = tor_strdup(tmp >= 0 ? buf : "internal error");
      return -1;
    }
  }
  /* Put keyword into canonical case. */
  if (strcmp(var->name, c->key)) {
    tor_free(c->key);
    c->key = tor_strdup(var->name);
  }

  if (!strlen(c->value)) {
    /* reset or clear it, then return */
    if (!clear_first) {
      if (var->type == CONFIG_TYPE_LINELIST ||
          var->type == CONFIG_TYPE_LINELIST_S) {
        /* We got an empty linelist from the torrc or commandline.
           As a special case, call this an error. Warn and ignore. */
        log_warn(LD_CONFIG,
                 "Linelist option '%s' has no value. Skipping.", c->key);
      } else { /* not already cleared */
        option_reset(fmt, options, var, use_defaults);
      }
    }
    return 0;
  }

  if (config_assign_value(fmt, options, c, msg) < 0)
    return -2;
  return 0;
}

/** Restore the option named <b>key</b> in options to its default value.
 * Called from config_assign(). */
static void
config_reset_line(config_format_t *fmt, or_options_t *options,
                  const char *key, int use_defaults)
{
  config_var_t *var;

  CHECK(fmt, options);

  var = config_find_option(fmt, key);
  if (!var)
    return; /* give error on next pass. */

  option_reset(fmt, options, var, use_defaults);
}

/** Return true iff key is a valid configuration option. */
int
option_is_recognized(const char *key)
{
  config_var_t *var = config_find_option(&options_format, key);
  return (var != NULL);
}

/** Return the canonical name of a configuration option. */
const char *
option_get_canonical_name(const char *key)
{
  config_var_t *var = config_find_option(&options_format, key);
  return var->name;
}

/** Return a canonicalized list of the options assigned for key.
 */
config_line_t *
option_get_assignment(or_options_t *options, const char *key)
{
  return get_assigned_option(&options_format, options, key);
}

/** Return a newly allocated deep copy of the lines in <b>inp</b>. */
static config_line_t *
config_lines_dup(const config_line_t *inp)
{
  config_line_t *result = NULL;
  config_line_t **next_out = &result;
  while (inp) {
    *next_out = tor_malloc(sizeof(config_line_t));
    (*next_out)->key = tor_strdup(inp->key);
    (*next_out)->value = tor_strdup(inp->value);
    inp = inp->next;
    next_out = &((*next_out)->next);
  }
  (*next_out) = NULL;
  return result;
}

/** Return newly allocated line or lines corresponding to <b>key</b> in the
 * configuration <b>options</b>.  Return NULL if no such key exists. */
static config_line_t *
get_assigned_option(config_format_t *fmt, or_options_t *options,
                    const char *key)
/* XXXX argument is options, but fmt is provided. Inconsistent. */
{
  config_var_t *var;
  const void *value;
  char buf[32];
  config_line_t *result;
  tor_assert(options && key);

  CHECK(fmt, options);

  var = config_find_option(fmt, key);
  if (!var) {
    log_warn(LD_CONFIG, "Unknown option '%s'.  Failing.", key);
    return NULL;
  }
  value = STRUCT_VAR_P(options, var->var_offset);

  result = tor_malloc_zero(sizeof(config_line_t));
  result->key = tor_strdup(var->name);
  switch (var->type)
    {
    case CONFIG_TYPE_STRING:
      if (*(char**)value) {
        result->value = tor_strdup(*(char**)value);
      } else {
        tor_free(result->key);
        tor_free(result);
        return NULL;
      }
      break;
    case CONFIG_TYPE_ISOTIME:
      if (*(time_t*)value) {
        result->value = tor_malloc(ISO_TIME_LEN+1);
        format_iso_time(result->value, *(time_t*)value);
      } else {
        tor_free(result->key);
        tor_free(result);
      }
      break;
    case CONFIG_TYPE_INTERVAL:
    case CONFIG_TYPE_UINT:
      /* This means every or_options_t uint or bool element
       * needs to be an int. Not, say, a uint16_t or char. */
      tor_snprintf(buf, sizeof(buf), "%d", *(int*)value);
      result->value = tor_strdup(buf);
      break;
    case CONFIG_TYPE_MEMUNIT:
      tor_snprintf(buf, sizeof(buf), U64_FORMAT,
                   U64_PRINTF_ARG(*(uint64_t*)value));
      result->value = tor_strdup(buf);
      break;
    case CONFIG_TYPE_DOUBLE:
      tor_snprintf(buf, sizeof(buf), "%f", *(double*)value);
      result->value = tor_strdup(buf);
      break;
    case CONFIG_TYPE_BOOL:
      result->value = tor_strdup(*(int*)value ? "1" : "0");
      break;
    case CONFIG_TYPE_CSV:
      if (*(smartlist_t**)value)
        result->value =
          smartlist_join_strings(*(smartlist_t**)value, ",", 0, NULL);
      else
        result->value = tor_strdup("");
      break;
    case CONFIG_TYPE_OBSOLETE:
      log_warn(LD_CONFIG,
               "You asked me for the value of an obsolete config option '%s'.",
               key);
      tor_free(result->key);
      tor_free(result);
      return NULL;
    case CONFIG_TYPE_LINELIST_S:
      log_warn(LD_CONFIG,
               "Can't return context-sensitive '%s' on its own", key);
      tor_free(result->key);
      tor_free(result);
      return NULL;
    case CONFIG_TYPE_LINELIST:
    case CONFIG_TYPE_LINELIST_V:
      tor_free(result->key);
      tor_free(result);
      return config_lines_dup(*(const config_line_t**)value);
    default:
      tor_free(result->key);
      tor_free(result);
      log_warn(LD_BUG,"Unknown type %d for known key '%s'",
               var->type, key);
      return NULL;
    }

  return result;
}

/** Iterate through the linked list of requested options <b>list</b>.
 * For each item, convert as appropriate and assign to <b>options</b>.
 * If an item is unrecognized, set *msg and return -1 immediately,
 * else return 0 for success.
 *
 * If <b>clear_first</b>, interpret config options as replacing (not
 * extending) their previous values. If <b>clear_first</b> is set,
 * then <b>use_defaults</b> to decide if you set to defaults after
 * clearing, or make the value 0 or NULL.
 *
 * Here are the use cases:
 * 1. A non-empty AllowInvalid line in your torrc. Appends to current
 *    if linelist, replaces current if csv.
 * 2. An empty AllowInvalid line in your torrc. Should clear it.
 * 3. "RESETCONF AllowInvalid" sets it to default.
 * 4. "SETCONF AllowInvalid" makes it NULL.
 * 5. "SETCONF AllowInvalid=foo" clears it and sets it to "foo".
 *
 * Use_defaults   Clear_first
 *    0                0       "append"
 *    1                0       undefined, don't use
 *    0                1       "set to null first"
 *    1                1       "set to defaults first"
 * Return 0 on success, -1 on bad key, -2 on bad value.
 *
 * As an additional special case, if a LINELIST config option has
 * no value and clear_first is 0, then warn and ignore it.
 */

/*
There are three call cases for config_assign() currently.

Case one: Torrc entry
options_init_from_torrc() calls config_assign(0, 0)
  calls config_assign_line(0, 0).
    if value is empty, calls option_reset(0) and returns.
    calls config_assign_value(), appends.

Case two: setconf
options_trial_assign() calls config_assign(0, 1)
  calls config_reset_line(0)
    calls option_reset(0)
      calls option_clear().
  calls config_assign_line(0, 1).
    if value is empty, returns.
    calls config_assign_value(), appends.

Case three: resetconf
options_trial_assign() calls config_assign(1, 1)
  calls config_reset_line(1)
    calls option_reset(1)
      calls option_clear().
      calls config_assign_value(default)
  calls config_assign_line(1, 1).
    returns.
*/
static int
config_assign(config_format_t *fmt, void *options, config_line_t *list,
              int use_defaults, int clear_first, char **msg)
{
  config_line_t *p;

  CHECK(fmt, options);

  /* pass 1: normalize keys */
  for (p = list; p; p = p->next) {
    const char *full = expand_abbrev(fmt, p->key, 0, 1);
    if (strcmp(full,p->key)) {
      tor_free(p->key);
      p->key = tor_strdup(full);
    }
  }

  /* pass 2: if we're reading from a resetting source, clear all
   * mentioned config options, and maybe set to their defaults. */
  if (clear_first) {
    for (p = list; p; p = p->next)
      config_reset_line(fmt, options, p->key, use_defaults);
  }

  /* pass 3: assign. */
  while (list) {
    int r;
    if ((r=config_assign_line(fmt, options, list, use_defaults,
                              clear_first, msg)))
      return r;
    list = list->next;
  }
  return 0;
}

/** Try assigning <b>list</b> to the global options. You do this by duping
 * options, assigning list to the new one, then validating it. If it's
 * ok, then throw out the old one and stick with the new one. Else,
 * revert to old and return failure.  Return 0 on success, -1 on bad
 * keys, -2 on bad values, -3 on bad transition, and -4 on failed-to-set.
 *
 * If not success, point *<b>msg</b> to a newly allocated string describing
 * what went wrong.
 */
int
options_trial_assign(config_line_t *list, int use_defaults,
                     int clear_first, char **msg)
{
  int r;
  or_options_t *trial_options = options_dup(&options_format, get_options());

  if ((r=config_assign(&options_format, trial_options,
                       list, use_defaults, clear_first, msg)) < 0) {
    config_free(&options_format, trial_options);
    return r;
  }

  if (options_validate(get_options(), trial_options, 1, msg) < 0) {
    config_free(&options_format, trial_options);
    return -2;
  }

  if (options_transition_allowed(get_options(), trial_options, msg) < 0) {
    config_free(&options_format, trial_options);
    return -3;
  }

  if (set_options(trial_options, msg)<0) {
    config_free(&options_format, trial_options);
    return -4;
  }

  /* we liked it. put it in place. */
  return 0;
}

/** Reset config option <b>var</b> to 0, 0.0, NULL, or the equivalent.
 * Called from option_reset() and config_free(). */
static void
option_clear(config_format_t *fmt, or_options_t *options, config_var_t *var)
{
  void *lvalue = STRUCT_VAR_P(options, var->var_offset);
  (void)fmt; /* unused */
  switch (var->type) {
    case CONFIG_TYPE_STRING:
      tor_free(*(char**)lvalue);
      break;
    case CONFIG_TYPE_DOUBLE:
      *(double*)lvalue = 0.0;
      break;
    case CONFIG_TYPE_ISOTIME:
      *(time_t*)lvalue = 0;
    case CONFIG_TYPE_INTERVAL:
    case CONFIG_TYPE_UINT:
    case CONFIG_TYPE_BOOL:
      *(int*)lvalue = 0;
      break;
    case CONFIG_TYPE_MEMUNIT:
      *(uint64_t*)lvalue = 0;
      break;
    case CONFIG_TYPE_CSV:
      if (*(smartlist_t**)lvalue) {
        SMARTLIST_FOREACH(*(smartlist_t **)lvalue, char *, cp, tor_free(cp));
        smartlist_free(*(smartlist_t **)lvalue);
        *(smartlist_t **)lvalue = NULL;
      }
      break;
    case CONFIG_TYPE_LINELIST:
    case CONFIG_TYPE_LINELIST_S:
      config_free_lines(*(config_line_t **)lvalue);
      *(config_line_t **)lvalue = NULL;
      break;
    case CONFIG_TYPE_LINELIST_V:
      /* handled by linelist_s. */
      break;
    case CONFIG_TYPE_OBSOLETE:
      break;
  }
}

/** Clear the option indexed by <b>var</b> in <b>options</b>. Then if
 * <b>use_defaults</b>, set it to its default value.
 * Called by config_init() and option_reset_line() and option_assign_line(). */
static void
option_reset(config_format_t *fmt, or_options_t *options,
             config_var_t *var, int use_defaults)
{
  config_line_t *c;
  char *msg = NULL;
  CHECK(fmt, options);
  option_clear(fmt, options, var); /* clear it first */
  if (!use_defaults)
    return; /* all done */
  if (var->initvalue) {
    c = tor_malloc_zero(sizeof(config_line_t));
    c->key = tor_strdup(var->name);
    c->value = tor_strdup(var->initvalue);
    if (config_assign_value(fmt, options, c, &msg) < 0) {
      log_warn(LD_BUG, "Failed to assign default: %s", msg);
      tor_free(msg); /* if this happens it's a bug */
    }
    config_free_lines(c);
  }
}

/** Print a usage message for tor. */
static void
print_usage(void)
{
  printf(
"Copyright 2001-2007 Roger Dingledine, Nick Mathewson.\n\n"
"tor -f <torrc> [args]\n"
"See man page for options, or http://tor.eff.org/ for documentation.\n");
}

/** Print all non-obsolete torrc options. */
static void
list_torrc_options(void)
{
  int i;
  smartlist_t *lines = smartlist_create();
  for (i = 0; _option_vars[i].name; ++i) {
    config_var_t *var = &_option_vars[i];
    const char *desc;
    if (var->type == CONFIG_TYPE_OBSOLETE ||
        var->type == CONFIG_TYPE_LINELIST_V)
      continue;
    desc = config_find_description(&options_format, var->name);
    printf("%s\n", var->name);
    if (desc) {
      wrap_string(lines, desc, 76, "    ", "    ");
      SMARTLIST_FOREACH(lines, char *, cp, {
          printf("%s", cp);
          tor_free(cp);
        });
      smartlist_clear(lines);
    }
  }
}

/** Last value actually set by resolve_my_address. */
static uint32_t last_resolved_addr = 0;
/**
 * Based on <b>options-\>Address</b>, guess our public IP address and put it
 * (in host order) into *<b>addr_out</b>. If <b>hostname_out</b> is provided,
 * set *<b>hostname_out</b> to a new string holding the hostname we used to
 * get the address. Return 0 if all is well, or -1 if we can't find a suitable
 * public IP address.
 */
int
resolve_my_address(int warn_severity, or_options_t *options,
                   uint32_t *addr_out, char **hostname_out)
{
  struct in_addr in;
  struct hostent *rent;
  char hostname[256];
  int explicit_ip=1;
  int explicit_hostname=1;
  int from_interface=0;
  char tmpbuf[INET_NTOA_BUF_LEN];
  const char *address = options->Address;
  int notice_severity = warn_severity <= LOG_NOTICE ?
                          LOG_NOTICE : warn_severity;

  tor_assert(addr_out);

  if (address && *address) {
    strlcpy(hostname, address, sizeof(hostname));
  } else { /* then we need to guess our address */
    explicit_ip = 0; /* it's implicit */
    explicit_hostname = 0; /* it's implicit */

    if (gethostname(hostname, sizeof(hostname)) < 0) {
      log_fn(warn_severity, LD_NET,"Error obtaining local hostname");
      return -1;
    }
    log_debug(LD_CONFIG,"Guessed local host name as '%s'",hostname);
  }

  /* now we know hostname. resolve it and keep only the IP address */

  if (tor_inet_aton(hostname, &in) == 0) {
    /* then we have to resolve it */
    explicit_ip = 0;
    rent = (struct hostent *)gethostbyname(hostname);
    if (!rent) {
      uint32_t interface_ip;

      if (explicit_hostname) {
        log_fn(warn_severity, LD_CONFIG,
               "Could not resolve local Address '%s'. Failing.", hostname);
        return -1;
      }
      log_fn(notice_severity, LD_CONFIG,
             "Could not resolve guessed local hostname '%s'. "
             "Trying something else.", hostname);
      if (get_interface_address(warn_severity, &interface_ip)) {
        log_fn(warn_severity, LD_CONFIG,
               "Could not get local interface IP address. Failing.");
        return -1;
      }
      from_interface = 1;
      in.s_addr = htonl(interface_ip);
      tor_inet_ntoa(&in,tmpbuf,sizeof(tmpbuf));
      log_fn(notice_severity, LD_CONFIG, "Learned IP address '%s' for "
             "local interface. Using that.", tmpbuf);
      strlcpy(hostname, "<guessed from interfaces>", sizeof(hostname));
    } else {
      tor_assert(rent->h_length == 4);
      memcpy(&in.s_addr, rent->h_addr, rent->h_length);

      if (!explicit_hostname &&
          is_internal_IP(ntohl(in.s_addr), 0)) {
        uint32_t interface_ip;

        tor_inet_ntoa(&in,tmpbuf,sizeof(tmpbuf));
        log_fn(notice_severity, LD_CONFIG, "Guessed local hostname '%s' "
               "resolves to a private IP address (%s).  Trying something "
               "else.", hostname, tmpbuf);

        if (get_interface_address(warn_severity, &interface_ip)) {
          log_fn(warn_severity, LD_CONFIG,
                 "Could not get local interface IP address. Too bad.");
        } else if (is_internal_IP(interface_ip, 0)) {
          struct in_addr in2;
          in2.s_addr = htonl(interface_ip);
          tor_inet_ntoa(&in2,tmpbuf,sizeof(tmpbuf));
          log_fn(notice_severity, LD_CONFIG,
                 "Interface IP address '%s' is a private address too. "
                 "Ignoring.", tmpbuf);
        } else {
          from_interface = 1;
          in.s_addr = htonl(interface_ip);
          tor_inet_ntoa(&in,tmpbuf,sizeof(tmpbuf));
          log_fn(notice_severity, LD_CONFIG,
                 "Learned IP address '%s' for local interface."
                 " Using that.", tmpbuf);
          strlcpy(hostname, "<guessed from interfaces>", sizeof(hostname));
        }
      }
    }
  }

  tor_inet_ntoa(&in,tmpbuf,sizeof(tmpbuf));
  if (is_internal_IP(ntohl(in.s_addr), 0) &&
      options->_PublishServerDescriptor) {
    /* make sure we're ok with publishing an internal IP */
    if (!options->DirServers) {
      /* if they are using the default dirservers, disallow internal IPs
       * always. */
      log_fn(warn_severity, LD_CONFIG,
             "Address '%s' resolves to private IP address '%s'. "
             "Tor servers that use the default DirServers must have public "
             "IP addresses.", hostname, tmpbuf);
      return -1;
    }
    if (!explicit_ip) {
      /* even if they've set their own dirservers, require an explicit IP if
       * they're using an internal address. */
      log_fn(warn_severity, LD_CONFIG, "Address '%s' resolves to private "
             "IP address '%s'. Please set the Address config option to be "
             "the IP address you want to use.", hostname, tmpbuf);
      return -1;
    }
  }

  log_debug(LD_CONFIG, "Resolved Address to '%s'.", tmpbuf);
  *addr_out = ntohl(in.s_addr);
  if (last_resolved_addr && last_resolved_addr != *addr_out) {
    /* Leave this as a notice, regardless of the requested severity,
     * at least until dynamic IP address support becomes bulletproof. */
    log_notice(LD_NET, "Your IP address seems to have changed. Updating.");
    ip_address_changed(0);
  }
  if (last_resolved_addr != *addr_out) {
    const char *method;
    const char *h = hostname;
    if (explicit_ip) {
      method = "CONFIGURED";
      h = NULL;
    } else if (explicit_hostname) {
      method = "RESOLVED";
    } else if (from_interface) {
      method = "INTERFACE";
      h = NULL;
    } else {
      method = "GETHOSTNAME";
    }
    control_event_server_status(LOG_NOTICE,
                                "EXTERNAL_ADDRESS ADDRESS=%s METHOD=%s %s%s",
                                tmpbuf, method, h?"HOSTNAME=":"", h);
  }
  last_resolved_addr = *addr_out;
  if (hostname_out)
    *hostname_out = tor_strdup(hostname);
  return 0;
}

/** Return true iff <b>ip</b> (in host order) is judged to be on the
 * same network as us, or on a private network.
 */
int
is_local_IP(uint32_t ip)
{
  if (is_internal_IP(ip, 0))
    return 1;
  /* Check whether ip is on the same /24 as we are. */
  if (get_options()->EnforceDistinctSubnets == 0)
    return 0;
  /* It's possible that this next check will hit before the first time
   * resolve_my_address actually succeeds.  (For clients, it is likely that
   * resolve_my_address will never be called at all).  In those cases,
   * last_resolved_addr will be 0, and so checking to see whether ip is on the
   * same /24 as last_resolved_addr will be the same as checking whether it
   * was on net 0, which is already done by is_internal_IP.
   */
  if ((last_resolved_addr & 0xffffff00ul) == (ip & 0xffffff00ul))
    return 1;
  return 0;
}

/** Called when we don't have a nickname set.  Try to guess a good nickname
 * based on the hostname, and return it in a newly allocated string. If we
 * can't, return NULL and let the caller warn if it wants to. */
static char *
get_default_nickname(void)
{
  static const char * const bad_default_nicknames[] = {
    "localhost",
    NULL,
  };
  char localhostname[256];
  char *cp, *out, *outp;
  int i;

  if (gethostname(localhostname, sizeof(localhostname)) < 0)
    return NULL;

  /* Put it in lowercase; stop at the first dot. */
  if ((cp = strchr(localhostname, '.')))
    *cp = '\0';
  tor_strlower(localhostname);

  /* Strip invalid characters. */
  cp = localhostname;
  out = outp = tor_malloc(strlen(localhostname) + 1);
  while (*cp) {
    if (strchr(LEGAL_NICKNAME_CHARACTERS, *cp))
      *outp++ = *cp++;
    else
      cp++;
  }
  *outp = '\0';

  /* Enforce length. */
  if (strlen(out) > MAX_NICKNAME_LEN)
    out[MAX_NICKNAME_LEN]='\0';

  /* Check for dumb names. */
  for (i = 0; bad_default_nicknames[i]; ++i) {
    if (!strcmp(out, bad_default_nicknames[i])) {
      tor_free(out);
      return NULL;
    }
  }

  return out;
}

/** Release storage held by <b>options</b>. */
static void
config_free(config_format_t *fmt, void *options)
{
  int i;

  tor_assert(options);

  for (i=0; fmt->vars[i].name; ++i)
    option_clear(fmt, options, &(fmt->vars[i]));
  if (fmt->extra) {
    config_line_t **linep = STRUCT_VAR_P(options, fmt->extra->var_offset);
    config_free_lines(*linep);
    *linep = NULL;
  }
  tor_free(options);
}

/** Return true iff a and b contain identical keys and values in identical
 * order. */
static int
config_lines_eq(config_line_t *a, config_line_t *b)
{
  while (a && b) {
    if (strcasecmp(a->key, b->key) || strcmp(a->value, b->value))
      return 0;
    a = a->next;
    b = b->next;
  }
  if (a || b)
    return 0;
  return 1;
}

/** Return true iff the option <b>var</b> has the same value in <b>o1</b>
 * and <b>o2</b>.  Must not be called for LINELIST_S or OBSOLETE options.
 */
static int
option_is_same(config_format_t *fmt,
               or_options_t *o1, or_options_t *o2, const char *name)
{
  config_line_t *c1, *c2;
  int r = 1;
  CHECK(fmt, o1);
  CHECK(fmt, o2);

  c1 = get_assigned_option(fmt, o1, name);
  c2 = get_assigned_option(fmt, o2, name);
  r = config_lines_eq(c1, c2);
  config_free_lines(c1);
  config_free_lines(c2);
  return r;
}

/** Copy storage held by <b>old</b> into a new or_options_t and return it. */
static or_options_t *
options_dup(config_format_t *fmt, or_options_t *old)
{
  or_options_t *newopts;
  int i;
  config_line_t *line;

  newopts = config_alloc(fmt);
  for (i=0; fmt->vars[i].name; ++i) {
    if (fmt->vars[i].type == CONFIG_TYPE_LINELIST_S)
      continue;
    if (fmt->vars[i].type == CONFIG_TYPE_OBSOLETE)
      continue;
    line = get_assigned_option(fmt, old, fmt->vars[i].name);
    if (line) {
      char *msg = NULL;
      if (config_assign(fmt, newopts, line, 0, 0, &msg) < 0) {
        log_err(LD_BUG, "Config_get_assigned_option() generated "
                "something we couldn't config_assign(): %s", msg);
        tor_free(msg);
        tor_assert(0);
      }
    }
    config_free_lines(line);
  }
  return newopts;
}

/** Return a new empty or_options_t.  Used for testing. */
or_options_t *
options_new(void)
{
  return config_alloc(&options_format);
}

/** Set <b>options</b> to hold reasonable defaults for most options.
 * Each option defaults to zero. */
void
options_init(or_options_t *options)
{
  config_init(&options_format, options);
}

/* Set all vars in the configuration object 'options' to their default
 * values. */
static void
config_init(config_format_t *fmt, void *options)
{
  int i;
  config_var_t *var;
  CHECK(fmt, options);

  for (i=0; fmt->vars[i].name; ++i) {
    var = &fmt->vars[i];
    if (!var->initvalue)
      continue; /* defaults to NULL or 0 */
    option_reset(fmt, options, var, 1);
  }
}

/** Allocate and return a new string holding the written-out values of the vars
 * in 'options'.  If 'minimal', do not write out any default-valued vars.
 * Else, if comment_defaults, write default values as comments.
 */
static char *
config_dump(config_format_t *fmt, void *options, int minimal,
            int comment_defaults)
{
  smartlist_t *elements;
  or_options_t *defaults;
  config_line_t *line, *assigned;
  char *result;
  int i;
  const char *desc;
  char *msg = NULL;

  defaults = config_alloc(fmt);
  config_init(fmt, defaults);

  /* XXX use a 1 here so we don't add a new log line while dumping */
  if (fmt->validate_fn(NULL,defaults, 1, &msg) < 0) {
    log_err(LD_BUG, "Failed to validate default config.");
    tor_free(msg);
    tor_assert(0);
  }

  elements = smartlist_create();
  for (i=0; fmt->vars[i].name; ++i) {
    int comment_option = 0;
    if (fmt->vars[i].type == CONFIG_TYPE_OBSOLETE ||
        fmt->vars[i].type == CONFIG_TYPE_LINELIST_S)
      continue;
    /* Don't save 'hidden' control variables. */
    if (!strcmpstart(fmt->vars[i].name, "__"))
      continue;
    if (minimal && option_is_same(fmt, options, defaults, fmt->vars[i].name))
      continue;
    else if (comment_defaults &&
             option_is_same(fmt, options, defaults, fmt->vars[i].name))
      comment_option = 1;

    desc = config_find_description(fmt, fmt->vars[i].name);
    line = assigned = get_assigned_option(fmt, options, fmt->vars[i].name);

    if (line && desc) {
      /* Only dump the description if there's something to describe. */
      wrap_string(elements, desc, 78, "# ", "# ");
    }

    for (; line; line = line->next) {
      size_t len = strlen(line->key) + strlen(line->value) + 5;
      char *tmp;
      tmp = tor_malloc(len);
      if (tor_snprintf(tmp, len, "%s%s %s\n",
                       comment_option ? "# " : "",
                       line->key, line->value)<0) {
        log_err(LD_BUG,"Internal error writing option value");
        tor_assert(0);
      }
      smartlist_add(elements, tmp);
    }
    config_free_lines(assigned);
  }

  if (fmt->extra) {
    line = *(config_line_t**)STRUCT_VAR_P(options, fmt->extra->var_offset);
    for (; line; line = line->next) {
      size_t len = strlen(line->key) + strlen(line->value) + 3;
      char *tmp;
      tmp = tor_malloc(len);
      if (tor_snprintf(tmp, len, "%s %s\n", line->key, line->value)<0) {
        log_err(LD_BUG,"Internal error writing option value");
        tor_assert(0);
      }
      smartlist_add(elements, tmp);
    }
  }

  result = smartlist_join_strings(elements, "", 0, NULL);
  SMARTLIST_FOREACH(elements, char *, cp, tor_free(cp));
  smartlist_free(elements);
  config_free(fmt, defaults);
  return result;
}

/** Return a string containing a possible configuration file that would give
 * the configuration in <b>options</b>.  If <b>minimal</b> is true, do not
 * include options that are the same as Tor's defaults.
 */
static char *
options_dump(or_options_t *options, int minimal)
{
  return config_dump(&options_format, options, minimal, 0);
}

/** Return 0 if every element of sl is a string holding a decimal
 * representation of a port number, or if sl is NULL.
 * Otherwise set *msg and return -1. */
static int
validate_ports_csv(smartlist_t *sl, const char *name, char **msg)
{
  int i;
  char buf[1024];
  tor_assert(name);

  if (!sl)
    return 0;

  SMARTLIST_FOREACH(sl, const char *, cp,
  {
    i = atoi(cp);
    if (i < 1 || i > 65535) {
      int r = tor_snprintf(buf, sizeof(buf),
                           "Port '%s' out of range in %s", cp, name);
      *msg = tor_strdup(r >= 0 ? buf : "internal error");
      return -1;
    }
  });
  return 0;
}

/** If <b>value</b> exceeds ROUTER_MAX_DECLARED_BANDWIDTH, write
 * a complaint into *<b>msg</b> using string <b>desc</b>, and return -1.
 * Else return 0.
 */
static int
ensure_bandwidth_cap(uint64_t *value, const char *desc, char **msg)
{
  int r;
  char buf[1024];
  if (*value > ROUTER_MAX_DECLARED_BANDWIDTH) {
    /* This handles an understandable special case where somebody says "2gb"
     * whereas our actual maximum is 2gb-1 (INT_MAX) */
    --*value;
  }
  if (*value > ROUTER_MAX_DECLARED_BANDWIDTH) {
    r = tor_snprintf(buf, sizeof(buf), "%s ("U64_FORMAT") must be at most %d",
                     desc, U64_PRINTF_ARG(*value),
                     ROUTER_MAX_DECLARED_BANDWIDTH);
    *msg = tor_strdup(r >= 0 ? buf : "internal error");
    return -1;
  }
  return 0;
}

/** Parse an authority type from <b>list</b> and write it to *<b>auth</b>.  If
 * <b>compatible</b> is non-zero, treat "1" as "v1,v2" and treat "0" as "".
 * Return 0 on success or -1 if not a recognized authority type (in which
 * case the value of *<b>auth</b> is undefined). */
static int
parse_authority_type_from_list(smartlist_t *list, authority_type_t *auth,
                               int compatible)
{
  tor_assert(auth);
  *auth = NO_AUTHORITY;
  if (!list) /* empty list, answer is none */
    return 0;
  SMARTLIST_FOREACH(list, const char *, string, {
    if (!strcasecmp(string, "v1"))
      *auth |= V1_AUTHORITY;
    else if (compatible && !strcmp(string, "1"))
      *auth |= V1_AUTHORITY | V2_AUTHORITY;
    else if (!strcasecmp(string, "v2"))
      *auth |= V2_AUTHORITY;
    else if (!strcasecmp(string, "v3"))
      *auth |= V3_AUTHORITY;
    else if (!strcasecmp(string, "bridge"))
      *auth |= BRIDGE_AUTHORITY;
    else if (!strcasecmp(string, "hidserv"))
      *auth |= HIDSERV_AUTHORITY;
    else if (!strcasecmp(string, "") || (compatible && !strcmp(string, "0")))
      /* no authority */;
    else
      return -1;
    });
  return 0;
}

/** Lowest allowable value for RendPostPeriod; if this is too low, hidden
 * services can overload the directory system. */
#define MIN_REND_POST_PERIOD (10*60)

/** Highest allowable value for RendPostPeriod. */
#define MAX_DIR_PERIOD (MIN_ONION_KEY_LIFETIME/2)

/** Return 0 if every setting in <b>options</b> is reasonable, and a
 * permissible transition from <b>old_options</b>. Else return -1.
 * Should have no side effects, except for normalizing the contents of
 * <b>options</b>.
 *
 * On error, tor_strdup an error explanation into *<b>msg</b>.
 *
 * XXX
 * If <b>from_setconf</b>, we were called by the controller, and our
 * Log line should stay empty. If it's 0, then give us a default log
 * if there are no logs defined.
 */
static int
options_validate(or_options_t *old_options, or_options_t *options,
                 int from_setconf, char **msg)
{
  int i, r;
  config_line_t *cl;
  const char *uname = get_uname();
  char buf[1024];
#define REJECT(arg) \
  STMT_BEGIN *msg = tor_strdup(arg); return -1; STMT_END
#define COMPLAIN(arg) STMT_BEGIN log(LOG_WARN, LD_CONFIG, arg); STMT_END

  tor_assert(msg);
  *msg = NULL;

  if (options->ORPort < 0 || options->ORPort > 65535)
    REJECT("ORPort option out of bounds.");

  if (server_mode(options) &&
      (!strcmpstart(uname, "Windows 95") ||
       !strcmpstart(uname, "Windows 98") ||
       !strcmpstart(uname, "Windows Me"))) {
    log(LOG_WARN, LD_CONFIG, "Tor is running as a server, but you are "
        "running %s; this probably won't work. See "
        "http://wiki.noreply.org/noreply/TheOnionRouter/TorFAQ#ServerOS "
        "for details.", uname);
  }

  if (options->ORPort == 0 && options->ORListenAddress != NULL)
    REJECT("ORPort must be defined if ORListenAddress is defined.");

  if (options->DirPort == 0 && options->DirListenAddress != NULL)
    REJECT("DirPort must be defined if DirListenAddress is defined.");

  if (options->DNSPort == 0 && options->DNSListenAddress != NULL)
    REJECT("DNSPort must be defined if DNSListenAddress is defined.");

  if (options->ControlPort == 0 && options->ControlListenAddress != NULL)
    REJECT("ControlPort must be defined if ControlListenAddress is defined.");

  if (options->TransPort == 0 && options->TransListenAddress != NULL)
    REJECT("TransPort must be defined if TransListenAddress is defined.");

  if (options->NatdPort == 0 && options->NatdListenAddress != NULL)
    REJECT("NatdPort must be defined if NatdListenAddress is defined.");

  /* Don't gripe about SocksPort 0 with SocksListenAddress set; a standard
   * configuration does this. */

  for (i = 0; i < 3; ++i) {
    int is_socks = i==0;
    int is_trans = i==1;
    config_line_t *line, *opt, *old;
    const char *tp;
    if (is_socks) {
      opt = options->SocksListenAddress;
      old = old_options ? old_options->SocksListenAddress : NULL;
      tp = "SOCKS proxy";
    } else if (is_trans) {
      opt = options->TransListenAddress;
      old = old_options ? old_options->TransListenAddress : NULL;
      tp = "transparent proxy";
    } else {
      opt = options->NatdListenAddress;
      old = old_options ? old_options->NatdListenAddress : NULL;
      tp = "natd proxy";
    }

    for (line = opt; line; line = line->next) {
      char *address = NULL;
      uint16_t port;
      uint32_t addr;
      if (parse_addr_port(LOG_WARN, line->value, &address, &addr, &port)<0)
        continue; /* We'll warn about this later. */
      if (!is_internal_IP(addr, 1) &&
          (!old_options || !config_lines_eq(old, opt))) {
        log_warn(LD_CONFIG,
             "You specified a public address '%s' for a %s. Other "
             "people on the Internet might find your computer and use it as "
             "an open %s. Please don't allow this unless you have "
             "a good reason.", address, tp, tp);
      }
      tor_free(address);
    }
  }

  if (validate_data_directory(options)<0)
    REJECT("Invalid DataDirectory");

  if (options->Nickname == NULL) {
    if (server_mode(options)) {
      if (!(options->Nickname = get_default_nickname())) {
        log_notice(LD_CONFIG, "Couldn't pick a nickname based on "
                   "our hostname; using %s instead.", UNNAMED_ROUTER_NICKNAME);
        options->Nickname = tor_strdup(UNNAMED_ROUTER_NICKNAME);
      } else {
        log_notice(LD_CONFIG, "Choosing default nickname '%s'",
                   options->Nickname);
      }
    }
  } else {
    if (!is_legal_nickname(options->Nickname)) {
      r = tor_snprintf(buf, sizeof(buf),
          "Nickname '%s' is wrong length or contains illegal characters.",
          options->Nickname);
      *msg = tor_strdup(r >= 0 ? buf : "internal error");
      return -1;
    }
  }

  if (server_mode(options) && !options->ContactInfo)
    log(LOG_NOTICE, LD_CONFIG, "Your ContactInfo config option is not set. "
        "Please consider setting it, so we can contact you if your server is "
        "misconfigured or something else goes wrong.");

  /* Special case on first boot if no Log options are given. */
  if (!options->Logs && !options->RunAsDaemon && !from_setconf)
    config_line_append(&options->Logs, "Log", "notice stdout");

  if (options_init_logs(options, 1)<0) /* Validate the log(s) */
    REJECT("Failed to validate Log options. See logs for details.");

  if (options->NoPublish) {
    log(LOG_WARN, LD_CONFIG,
        "NoPublish is obsolete. Use PublishServerDescriptor instead.");
    SMARTLIST_FOREACH(options->PublishServerDescriptor, char *, s,
                      tor_free(s));
    smartlist_clear(options->PublishServerDescriptor);
  }

  if (authdir_mode(options)) {
    /* confirm that our address isn't broken, so we can complain now */
    uint32_t tmp;
    if (resolve_my_address(LOG_WARN, options, &tmp, NULL) < 0)
      REJECT("Failed to resolve/guess local address. See logs for details.");
  }

#ifndef MS_WINDOWS
  if (options->RunAsDaemon && torrc_fname && path_is_relative(torrc_fname))
    REJECT("Can't use a relative path to torrc when RunAsDaemon is set.");
#endif

  if (options->SocksPort < 0 || options->SocksPort > 65535)
    REJECT("SocksPort option out of bounds.");

  if (options->DNSPort < 0 || options->DNSPort > 65535)
    REJECT("DNSPort option out of bounds.");

  if (options->TransPort < 0 || options->TransPort > 65535)
    REJECT("TransPort option out of bounds.");

  if (options->NatdPort < 0 || options->NatdPort > 65535)
    REJECT("NatdPort option out of bounds.");

  if (options->SocksPort == 0 && options->TransPort == 0 &&
      options->NatdPort == 0 && options->ORPort == 0)
    REJECT("SocksPort, TransPort, NatdPort, and ORPort are all undefined? "
           "Quitting.");

  if (options->ControlPort < 0 || options->ControlPort > 65535)
    REJECT("ControlPort option out of bounds.");

  if (options->DirPort < 0 || options->DirPort > 65535)
    REJECT("DirPort option out of bounds.");

#ifndef USE_TRANSPARENT
  if (options->TransPort || options->TransListenAddress)
    REJECT("TransPort and TransListenAddress are disabled in this build.");
#endif

  if (options->StrictExitNodes &&
      (!options->ExitNodes || !strlen(options->ExitNodes)) &&
      (!old_options ||
       (old_options->StrictExitNodes != options->StrictExitNodes) ||
       (!opt_streq(old_options->ExitNodes, options->ExitNodes))))
    COMPLAIN("StrictExitNodes set, but no ExitNodes listed.");

  if (options->StrictEntryNodes &&
      (!options->EntryNodes || !strlen(options->EntryNodes)) &&
      (!old_options ||
       (old_options->StrictEntryNodes != options->StrictEntryNodes) ||
       (!opt_streq(old_options->EntryNodes, options->EntryNodes))))
    COMPLAIN("StrictEntryNodes set, but no EntryNodes listed.");

  if (options->AuthoritativeDir) {
    if (!options->ContactInfo)
      REJECT("Authoritative directory servers must set ContactInfo");
    if (options->V1AuthoritativeDir && !options->RecommendedVersions)
      REJECT("V1 auth dir servers must set RecommendedVersions.");
    if (!options->RecommendedClientVersions)
      options->RecommendedClientVersions =
        config_lines_dup(options->RecommendedVersions);
    if (!options->RecommendedServerVersions)
      options->RecommendedServerVersions =
        config_lines_dup(options->RecommendedVersions);
    if (options->VersioningAuthoritativeDir &&
        (!options->RecommendedClientVersions ||
         !options->RecommendedServerVersions))
      REJECT("Versioning auth dir servers must set Recommended*Versions.");
    if (options->UseEntryGuards) {
      log_info(LD_CONFIG, "Authoritative directory servers can't set "
               "UseEntryGuards. Disabling.");
      options->UseEntryGuards = 0;
    }
    if (!options->DownloadExtraInfo) {
      log_info(LD_CONFIG, "Authoritative directories always try to download "
               "extra-info documents. Setting DownloadExtraInfo.");
      options->DownloadExtraInfo = 1;
    }
    if (!(options->BridgeAuthoritativeDir || options->HSAuthoritativeDir ||
          options->V1AuthoritativeDir || options->V2AuthoritativeDir ||
          options->V3AuthoritativeDir))
      REJECT("AuthoritativeDir is set, but none of "
             "(Bridge/HS/V1/V2/V3)AuthoriativeDir is set.");
  }

  if (options->AuthoritativeDir && !options->DirPort)
    REJECT("Running as authoritative directory, but no DirPort set.");

  if (options->AuthoritativeDir && !options->ORPort)
    REJECT("Running as authoritative directory, but no ORPort set.");

  if (options->AuthoritativeDir && options->ClientOnly)
    REJECT("Running as authoritative directory, but ClientOnly also set.");

  if (options->HSAuthorityRecordStats && !options->HSAuthoritativeDir)
    REJECT("HSAuthorityRecordStats is set but we're not running as "
           "a hidden service authority.");

  if (options->ConnLimit <= 0) {
    r = tor_snprintf(buf, sizeof(buf),
        "ConnLimit must be greater than 0, but was set to %d",
        options->ConnLimit);
    *msg = tor_strdup(r >= 0 ? buf : "internal error");
    return -1;
  }

  if (validate_ports_csv(options->FirewallPorts, "FirewallPorts", msg) < 0)
    return -1;

  if (validate_ports_csv(options->LongLivedPorts, "LongLivedPorts", msg) < 0)
    return -1;

  if (options->FascistFirewall && !options->ReachableAddresses) {
    if (options->FirewallPorts && smartlist_len(options->FirewallPorts)) {
      /* We already have firewall ports set, so migrate them to
       * ReachableAddresses, which will set ReachableORAddresses and
       * ReachableDirAddresses if they aren't set explicitly. */
      smartlist_t *instead = smartlist_create();
      config_line_t *new_line = tor_malloc_zero(sizeof(config_line_t));
      new_line->key = tor_strdup("ReachableAddresses");
      /* If we're configured with the old format, we need to prepend some
       * open ports. */
      SMARTLIST_FOREACH(options->FirewallPorts, const char *, portno,
      {
        int p = atoi(portno);
        char *s;
        if (p<0) continue;
        s = tor_malloc(16);
        tor_snprintf(s, 16, "*:%d", p);
        smartlist_add(instead, s);
      });
      new_line->value = smartlist_join_strings(instead,",",0,NULL);
      /* These have been deprecated since 0.1.1.5-alpha-cvs */
      log(LOG_NOTICE, LD_CONFIG,
          "Converting FascistFirewall and FirewallPorts "
          "config options to new format: \"ReachableAddresses %s\"",
          new_line->value);
      options->ReachableAddresses = new_line;
      SMARTLIST_FOREACH(instead, char *, cp, tor_free(cp));
      smartlist_free(instead);
    } else {
      /* We do not have FirewallPorts set, so add 80 to
       * ReachableDirAddresses, and 443 to ReachableORAddresses. */
      if (!options->ReachableDirAddresses) {
        config_line_t *new_line = tor_malloc_zero(sizeof(config_line_t));
        new_line->key = tor_strdup("ReachableDirAddresses");
        new_line->value = tor_strdup("*:80");
        options->ReachableDirAddresses = new_line;
        log(LOG_NOTICE, LD_CONFIG, "Converting FascistFirewall config option "
            "to new format: \"ReachableDirAddresses *:80\"");
      }
      if (!options->ReachableORAddresses) {
        config_line_t *new_line = tor_malloc_zero(sizeof(config_line_t));
        new_line->key = tor_strdup("ReachableORAddresses");
        new_line->value = tor_strdup("*:443");
        options->ReachableORAddresses = new_line;
        log(LOG_NOTICE, LD_CONFIG, "Converting FascistFirewall config option "
            "to new format: \"ReachableORAddresses *:443\"");
      }
    }
  }

  for (i=0; i<3; i++) {
    config_line_t **linep =
      (i==0) ? &options->ReachableAddresses :
        (i==1) ? &options->ReachableORAddresses :
                 &options->ReachableDirAddresses;
    if (!*linep)
      continue;
    /* We need to end with a reject *:*, not an implicit accept *:* */
    for (;;) {
      if (!strcmp((*linep)->value, "reject *:*")) /* already there */
        break;
      linep = &((*linep)->next);
      if (!*linep) {
        *linep = tor_malloc_zero(sizeof(config_line_t));
        (*linep)->key = tor_strdup(
          (i==0) ?  "ReachableAddresses" :
            (i==1) ? "ReachableORAddresses" :
                     "ReachableDirAddresses");
        (*linep)->value = tor_strdup("reject *:*");
        break;
      }
    }
  }

  if ((options->ReachableAddresses ||
       options->ReachableORAddresses ||
       options->ReachableDirAddresses) &&
      server_mode(options))
    REJECT("Servers must be able to freely connect to the rest "
           "of the Internet, so they must not set Reachable*Addresses "
           "or FascistFirewall.");

  options->_AllowInvalid = 0;
  if (options->AllowInvalidNodes) {
    SMARTLIST_FOREACH(options->AllowInvalidNodes, const char *, cp, {
        if (!strcasecmp(cp, "entry"))
          options->_AllowInvalid |= ALLOW_INVALID_ENTRY;
        else if (!strcasecmp(cp, "exit"))
          options->_AllowInvalid |= ALLOW_INVALID_EXIT;
        else if (!strcasecmp(cp, "middle"))
          options->_AllowInvalid |= ALLOW_INVALID_MIDDLE;
        else if (!strcasecmp(cp, "introduction"))
          options->_AllowInvalid |= ALLOW_INVALID_INTRODUCTION;
        else if (!strcasecmp(cp, "rendezvous"))
          options->_AllowInvalid |= ALLOW_INVALID_RENDEZVOUS;
        else {
          r = tor_snprintf(buf, sizeof(buf),
              "Unrecognized value '%s' in AllowInvalidNodes", cp);
          *msg = tor_strdup(r >= 0 ? buf : "internal error");
          return -1;
        }
      });
  }

  if ((i = parse_authority_type_from_list(options->PublishServerDescriptor,
                               &options->_PublishServerDescriptor, 1) < 0)) {
    r = tor_snprintf(buf, sizeof(buf),
        "Unrecognized value '%s' for PublishServerDescriptor",
                  (char*)smartlist_get(options->PublishServerDescriptor, -i));
    *msg = tor_strdup(r >= 0 ? buf : "internal error");
    return -1;
  }

  if (options->RendPostPeriod < MIN_REND_POST_PERIOD) {
    log(LOG_WARN,LD_CONFIG,"RendPostPeriod option must be at least %d seconds."
        " Clipping.", MIN_REND_POST_PERIOD);
    options->RendPostPeriod = MIN_REND_POST_PERIOD;
  }

  if (options->RendPostPeriod > MAX_DIR_PERIOD) {
    log(LOG_WARN, LD_CONFIG, "RendPostPeriod is too large; clipping to %ds.",
        MAX_DIR_PERIOD);
    options->RendPostPeriod = MAX_DIR_PERIOD;
  }

  if (options->KeepalivePeriod < 1)
    REJECT("KeepalivePeriod option must be positive.");

  if (ensure_bandwidth_cap(&options->BandwidthRate,
                           "BandwidthRate", msg) < 0)
    return -1;
  if (ensure_bandwidth_cap(&options->BandwidthBurst,
                           "BandwidthBurst", msg) < 0)
    return -1;
  if (ensure_bandwidth_cap(&options->MaxAdvertisedBandwidth,
                           "MaxAdvertisedBandwidth", msg) < 0)
    return -1;
  if (ensure_bandwidth_cap(&options->RelayBandwidthRate,
                           "RelayBandwidthRate", msg) < 0)
    return -1;
  if (ensure_bandwidth_cap(&options->RelayBandwidthBurst,
                           "RelayBandwidthBurst", msg) < 0)
    return -1;

  if (server_mode(options)) {
    if (options->BandwidthRate < ROUTER_REQUIRED_MIN_BANDWIDTH*2) {
      r = tor_snprintf(buf, sizeof(buf),
                       "BandwidthRate is set to %d bytes/second. "
                       "For servers, it must be at least %d.",
                       (int)options->BandwidthRate,
                       ROUTER_REQUIRED_MIN_BANDWIDTH*2);
      *msg = tor_strdup(r >= 0 ? buf : "internal error");
      return -1;
    } else if (options->MaxAdvertisedBandwidth <
               ROUTER_REQUIRED_MIN_BANDWIDTH) {
      r = tor_snprintf(buf, sizeof(buf),
                       "MaxAdvertisedBandwidth is set to %d bytes/second. "
                       "For servers, it must be at least %d.",
                       (int)options->MaxAdvertisedBandwidth,
                       ROUTER_REQUIRED_MIN_BANDWIDTH);
      *msg = tor_strdup(r >= 0 ? buf : "internal error");
      return -1;
    }
    if (options->RelayBandwidthRate > options->RelayBandwidthBurst)
      REJECT("RelayBandwidthBurst must be at least equal "
             "to RelayBandwidthRate.");
    if (options->RelayBandwidthRate &&
      options->RelayBandwidthRate < ROUTER_REQUIRED_MIN_BANDWIDTH) {
      r = tor_snprintf(buf, sizeof(buf),
                       "RelayBandwidthRate is set to %d bytes/second. "
                       "For servers, it must be at least %d.",
                       (int)options->RelayBandwidthRate,
                       ROUTER_REQUIRED_MIN_BANDWIDTH);
      *msg = tor_strdup(r >= 0 ? buf : "internal error");
      return -1;
    }
  }

  if (options->BandwidthRate > options->BandwidthBurst)
    REJECT("BandwidthBurst must be at least equal to BandwidthRate.");

  if (accounting_parse_options(options, 1)<0)
    REJECT("Failed to parse accounting options. See logs for details.");

  if (options->HttpProxy) { /* parse it now */
    if (parse_addr_port(LOG_WARN, options->HttpProxy, NULL,
                        &options->HttpProxyAddr, &options->HttpProxyPort) < 0)
      REJECT("HttpProxy failed to parse or resolve. Please fix.");
    if (options->HttpProxyPort == 0) { /* give it a default */
      options->HttpProxyPort = 80;
    }
  }

  if (options->HttpProxyAuthenticator) {
    if (strlen(options->HttpProxyAuthenticator) >= 48)
      REJECT("HttpProxyAuthenticator is too long (>= 48 chars).");
  }

  if (options->HttpsProxy) { /* parse it now */
    if (parse_addr_port(LOG_WARN, options->HttpsProxy, NULL,
                        &options->HttpsProxyAddr, &options->HttpsProxyPort) <0)
      REJECT("HttpsProxy failed to parse or resolve. Please fix.");
    if (options->HttpsProxyPort == 0) { /* give it a default */
      options->HttpsProxyPort = 443;
    }
  }

  if (options->HttpsProxyAuthenticator) {
    if (strlen(options->HttpsProxyAuthenticator) >= 48)
      REJECT("HttpsProxyAuthenticator is too long (>= 48 chars).");
  }

  if (options->HashedControlPassword) {
    if (decode_hashed_password(NULL, options->HashedControlPassword)<0)
      REJECT("Bad HashedControlPassword: wrong length or bad encoding");
  }

  if (options->ControlListenAddress) {
    int all_are_local = 1;
    config_line_t *ln;
    for (ln = options->ControlListenAddress; ln; ln = ln->next) {
      if (strcmpstart(ln->value, "127."))
        all_are_local = 0;
    }
    if (!all_are_local) {
      if (!options->HashedControlPassword && !options->CookieAuthentication) {
        log_warn(LD_CONFIG, "You have a ControlListenAddress set to accept "
                 "connections from a non-local address.  This means that "
                 "any program on the internet can reconfigure your Tor. "
                 "That's so bad that I'm closing your ControlPort for you.");
        options->ControlPort = 0;
      } else {
        log_warn(LD_CONFIG, "You have a ControlListenAddress set to accept "
                 "connections from a non-local address.  This means that "
                 "programs not running on your computer can reconfigure your "
                 "Tor.  That's pretty bad!");
      }
    }
  }

  if (options->ControlPort && !options->HashedControlPassword &&
      !options->CookieAuthentication) {
    log_warn(LD_CONFIG, "ControlPort is open, but no authentication method "
             "has been configured.  This means that any program on your "
             "computer can reconfigure your Tor.  That's bad!  You should "
             "upgrade your Tor controller as soon as possible.");
  }

  if (options->UseEntryGuards && ! options->NumEntryGuards)
    REJECT("Cannot enable UseEntryGuards with NumEntryGuards set to 0");

  if (check_nickname_list(options->ExitNodes, "ExitNodes", msg))
    return -1;
  if (check_nickname_list(options->EntryNodes, "EntryNodes", msg))
    return -1;
  if (check_nickname_list(options->ExcludeNodes, "ExcludeNodes", msg))
    return -1;
  if (check_nickname_list(options->RendNodes, "RendNodes", msg))
    return -1;
  if (check_nickname_list(options->RendNodes, "RendExcludeNodes", msg))
    return -1;
  if (check_nickname_list(options->TestVia, "TestVia", msg))
    return -1;
  if (check_nickname_list(options->MyFamily, "MyFamily", msg))
    return -1;
  for (cl = options->NodeFamilies; cl; cl = cl->next) {
    if (check_nickname_list(cl->value, "NodeFamily", msg))
      return -1;
  }

  if (validate_addr_policies(options, msg) < 0)
    return -1;

  for (cl = options->RedirectExit; cl; cl = cl->next) {
    if (parse_redirect_line(NULL, cl, msg)<0)
      return -1;
  }

  if (options->DirServers) {
    if (!old_options ||
        !config_lines_eq(options->DirServers, old_options->DirServers))
        COMPLAIN("You have used DirServer to specify directory authorities in "
                 "your configuration.  This is potentially dangerous: it can "
                 "make you look different from all other Tor users, and hurt "
                 "your anonymity.  Even if you've specified the same "
                 "authorities as Tor uses by default, the defaults could "
                 "change in the future.  Be sure you know what you're doing.");
    for (cl = options->DirServers; cl; cl = cl->next) {
      if (parse_dir_server_line(cl->value, 1)<0)
        REJECT("DirServer line did not parse. See logs for details.");
    }
  }

  if (options->UseBridges && !options->Bridges)
    REJECT("If you set UseBridges, you must specify at least one bridge.");
  if (options->UseBridges && !options->TunnelDirConns)
    REJECT("If you set UseBridges, you must set TunnelDirConns.");
  if (options->Bridges) {
    for (cl = options->Bridges; cl; cl = cl->next) {
      if (parse_bridge_line(cl->value, 1)<0)
        REJECT("Bridge line did not parse. See logs for details.");
    }
  }

  if (options->ConstrainedSockets) {
    /* If the user wants to constrain socket buffer use, make sure the desired
     * limit is between MIN|MAX_TCPSOCK_BUFFER in k increments. */
    if (options->ConstrainedSockSize < MIN_CONSTRAINED_TCP_BUFFER ||
        options->ConstrainedSockSize > MAX_CONSTRAINED_TCP_BUFFER ||
        options->ConstrainedSockSize % 1024) {
      r = tor_snprintf(buf, sizeof(buf),
          "ConstrainedSockSize is invalid.  Must be a value between %d and %d "
          "in 1024 byte increments.",
          MIN_CONSTRAINED_TCP_BUFFER, MAX_CONSTRAINED_TCP_BUFFER);
      *msg = tor_strdup(r >= 0 ? buf : "internal error");
      return -1;
    }
    if (options->DirPort) {
      /* Providing cached directory entries while system TCP buffers are scarce
       * will exacerbate the socket errors.  Suggest that this be disabled. */
      COMPLAIN("You have requested constrained socket buffers while also "
               "serving directory entries via DirPort.  It is strongly "
               "suggested that you disable serving directory requests when "
               "system TCP buffer resources are scarce.");
    }
  }

  if (options->V3AuthVoteDelay + options->V3AuthDistDelay >=
      options->V3AuthVotingInterval/2) {
    REJECT("V3AuthVoteDelay and V3AuthDistDelay must be no more than half "
           "V3AuthVotingInterval");
  }
  if (options->V3AuthVoteDelay < MIN_VOTE_SECONDS)
    REJECT("V3AuthVoteDelay is way too low.");
  if (options->V3AuthDistDelay < MIN_DIST_SECONDS)
    REJECT("V3AuthDistDelay is way too low.");

  if (options->V3AuthNIntervalsValid < 2)
    REJECT("V3AuthNIntervalsValid must be at least 2.");

  if (options->V3AuthVotingInterval < MIN_VOTE_INTERVAL) {
    REJECT("V3AuthVotingInterval is insanely low.");
  } else if (options->V3AuthVotingInterval > 24*60*60) {
    REJECT("V3AuthVotingInterval is insanely high.");
  } else if (((24*60*60) % options->V3AuthVotingInterval) != 0) {
    COMPLAIN("V3AuthVotingInterval does not divide evenly into 24 hours.");
  }

  if (rend_config_services(options, 1) < 0)
    REJECT("Failed to configure rendezvous options. See logs for details.");

  if (parse_virtual_addr_network(options->VirtualAddrNetwork, 1, NULL)<0)
    return -1;

  if (options->PreferTunneledDirConns && !options->TunnelDirConns)
    REJECT("Must set TunnelDirConns if PreferTunneledDirConns is set.");

  if (options->AutomapHostsSuffixes) {
    SMARTLIST_FOREACH(options->AutomapHostsSuffixes, char *, suf,
    {
      size_t len = strlen(suf);
      if (len && suf[len-1] == '.')
        suf[len-1] = '\0';
    });
  }

  return 0;
#undef REJECT
#undef COMPLAIN
}

/** Helper: return true iff s1 and s2 are both NULL, or both non-NULL
 * equal strings. */
static int
opt_streq(const char *s1, const char *s2)
{
  if (!s1 && !s2)
    return 1;
  else if (s1 && s2 && !strcmp(s1,s2))
    return 1;
  else
    return 0;
}

/** Check if any of the previous options have changed but aren't allowed to. */
static int
options_transition_allowed(or_options_t *old, or_options_t *new_val,
                           char **msg)
{
  if (!old)
    return 0;

  if (!opt_streq(old->PidFile, new_val->PidFile)) {
    *msg = tor_strdup("PidFile is not allowed to change.");
    return -1;
  }

  if (old->RunAsDaemon != new_val->RunAsDaemon) {
    *msg = tor_strdup("While Tor is running, changing RunAsDaemon "
                      "is not allowed.");
    return -1;
  }

  if (strcmp(old->DataDirectory,new_val->DataDirectory)!=0) {
    char buf[1024];
    int r = tor_snprintf(buf, sizeof(buf),
               "While Tor is running, changing DataDirectory "
               "(\"%s\"->\"%s\") is not allowed.",
               old->DataDirectory, new_val->DataDirectory);
    *msg = tor_strdup(r >= 0 ? buf : "internal error");
    return -1;
  }

  if (!opt_streq(old->User, new_val->User)) {
    *msg = tor_strdup("While Tor is running, changing User is not allowed.");
    return -1;
  }

  if (!opt_streq(old->Group, new_val->Group)) {
    *msg = tor_strdup("While Tor is running, changing Group is not allowed.");
    return -1;
  }

  if (old->HardwareAccel != new_val->HardwareAccel) {
    *msg = tor_strdup("While Tor is running, changing HardwareAccel is "
                      "not allowed.");
    return -1;
  }

  return 0;
}

/** Return 1 if any change from <b>old_options</b> to <b>new_options</b>
 * will require us to rotate the cpu and dns workers; else return 0. */
static int
options_transition_affects_workers(or_options_t *old_options,
                                   or_options_t *new_options)
{
  if (!opt_streq(old_options->DataDirectory, new_options->DataDirectory) ||
      old_options->NumCpus != new_options->NumCpus ||
      old_options->ORPort != new_options->ORPort ||
      old_options->ServerDNSSearchDomains !=
                                       new_options->ServerDNSSearchDomains ||
      old_options->SafeLogging != new_options->SafeLogging ||
      old_options->ClientOnly != new_options->ClientOnly ||
      !config_lines_eq(old_options->Logs, new_options->Logs))
    return 1;

  /* Check whether log options match. */

  /* Nothing that changed matters. */
  return 0;
}

/** Return 1 if any change from <b>old_options</b> to <b>new_options</b>
 * will require us to generate a new descriptor; else return 0. */
static int
options_transition_affects_descriptor(or_options_t *old_options,
                                      or_options_t *new_options)
{
  if (!opt_streq(old_options->DataDirectory, new_options->DataDirectory) ||
      !opt_streq(old_options->Nickname,new_options->Nickname) ||
      !opt_streq(old_options->Address,new_options->Address) ||
      !config_lines_eq(old_options->ExitPolicy,new_options->ExitPolicy) ||
      old_options->ORPort != new_options->ORPort ||
      old_options->DirPort != new_options->DirPort ||
      old_options->ClientOnly != new_options->ClientOnly ||
      old_options->NoPublish != new_options->NoPublish ||
      old_options->_PublishServerDescriptor !=
        new_options->_PublishServerDescriptor ||
      old_options->BandwidthRate != new_options->BandwidthRate ||
      old_options->BandwidthBurst != new_options->BandwidthBurst ||
      !opt_streq(old_options->ContactInfo, new_options->ContactInfo) ||
      !opt_streq(old_options->MyFamily, new_options->MyFamily) ||
      !opt_streq(old_options->AccountingStart, new_options->AccountingStart) ||
      old_options->AccountingMax != new_options->AccountingMax)
    return 1;

  return 0;
}

#ifdef MS_WINDOWS
/** Return the directory on windows where we expect to find our application
 * data. */
static char *
get_windows_conf_root(void)
{
  static int is_set = 0;
  static char path[MAX_PATH+1];

  LPITEMIDLIST idl;
  IMalloc *m;
  HRESULT result;

  if (is_set)
    return path;

  /* Find X:\documents and settings\username\application data\ .
   * We would use SHGetSpecialFolder path, but that wasn't added until IE4.
   */
  if (!SUCCEEDED(SHGetSpecialFolderLocation(NULL, CSIDL_APPDATA,
                                            &idl))) {
    GetCurrentDirectory(MAX_PATH, path);
    is_set = 1;
    log_warn(LD_CONFIG,
             "I couldn't find your application data folder: are you "
             "running an ancient version of Windows 95? Defaulting to \"%s\"",
             path);
    return path;
  }
  /* Convert the path from an "ID List" (whatever that is!) to a path. */
  result = SHGetPathFromIDList(idl, path);
  /* Now we need to free the */
  SHGetMalloc(&m);
  if (m) {
    m->lpVtbl->Free(m, idl);
    m->lpVtbl->Release(m);
  }
  if (!SUCCEEDED(result)) {
    return NULL;
  }
  strlcat(path,"\\tor",MAX_PATH);
  is_set = 1;
  return path;
}
#endif

/** Return the default location for our torrc file. */
static const char *
get_default_conf_file(void)
{
#ifdef MS_WINDOWS
  static char path[MAX_PATH+1];
  strlcpy(path, get_windows_conf_root(), MAX_PATH);
  strlcat(path,"\\torrc",MAX_PATH);
  return path;
#else
  return (CONFDIR "/torrc");
#endif
}

/** Verify whether lst is a string containing valid-looking space-separated
 * nicknames, or NULL. Return 0 on success. Warn and return -1 on failure.
 */
static int
check_nickname_list(const char *lst, const char *name, char **msg)
{
  int r = 0;
  smartlist_t *sl;

  if (!lst)
    return 0;
  sl = smartlist_create();
  smartlist_split_string(sl, lst, ",", SPLIT_SKIP_SPACE|SPLIT_IGNORE_BLANK, 0);
  SMARTLIST_FOREACH(sl, const char *, s,
    {
      if (!is_legal_nickname_or_hexdigest(s)) {
        char buf[1024];
        int tmp = tor_snprintf(buf, sizeof(buf),
                  "Invalid nickname '%s' in %s line", s, name);
        *msg = tor_strdup(tmp >= 0 ? buf : "internal error");
        r = -1;
        break;
      }
    });
  SMARTLIST_FOREACH(sl, char *, s, tor_free(s));
  smartlist_free(sl);
  return r;
}

/** Read a configuration file into <b>options</b>, finding the configuration
 * file location based on the command line.  After loading the options,
 * validate them for consistency, then take actions based on them.
 * Return 0 if success, -1 if failure. */
int
options_init_from_torrc(int argc, char **argv)
{
  or_options_t *oldoptions, *newoptions;
  config_line_t *cl;
  char *cf=NULL, *fname=NULL, *errmsg=NULL;
  int i, retval;
  int using_default_torrc;
  int ignore_missing_torrc;
  static char **backup_argv;
  static int backup_argc;

  if (argv) { /* first time we're called. save commandline args */
    backup_argv = argv;
    backup_argc = argc;
    oldoptions = NULL;
  } else { /* we're reloading. need to clean up old options first. */
    argv = backup_argv;
    argc = backup_argc;
    oldoptions = get_options();
  }
  if (argc > 1 && (!strcmp(argv[1], "-h") || !strcmp(argv[1],"--help"))) {
    print_usage();
    exit(0);
  }
  if (argc > 1 && !strcmp(argv[1], "--list-torrc-options")) {
    /* For documenting validating whether we've documented everything. */
    list_torrc_options();
    exit(0);
  }

  if (argc > 1 && (!strcmp(argv[1],"--version"))) {
    printf("Tor version %s.\n",get_version());
    if (argc > 2 && (!strcmp(argv[2],"--version"))) {
      print_svn_version();
    }
    exit(0);
  }

  newoptions = tor_malloc_zero(sizeof(or_options_t));
  newoptions->_magic = OR_OPTIONS_MAGIC;
  options_init(newoptions);

  /* learn config file name */
  fname = NULL;
  using_default_torrc = 1;
  ignore_missing_torrc = 0;
  newoptions->command = CMD_RUN_TOR;
  for (i = 1; i < argc; ++i) {
    if (i < argc-1 && !strcmp(argv[i],"-f")) {
      if (fname) {
        log(LOG_WARN, LD_CONFIG, "Duplicate -f options on command line.");
        tor_free(fname);
      }
#ifdef MS_WINDOWS
      /* XXX one day we might want to extend expand_filename to work
       * under Windows as well. */
      fname = tor_strdup(argv[i+1]);
#else
      fname = expand_filename(argv[i+1]);
#endif
      using_default_torrc = 0;
      ++i;
    } else if (!strcmp(argv[i],"--ignore-missing-torrc")) {
      ignore_missing_torrc = 1;
    } else if (!strcmp(argv[i],"--list-fingerprint")) {
      newoptions->command = CMD_LIST_FINGERPRINT;
    } else if (!strcmp(argv[i],"--hash-password")) {
      newoptions->command = CMD_HASH_PASSWORD;
      newoptions->command_arg = tor_strdup( (i < argc-1) ? argv[i+1] : "");
      ++i;
    } else if (!strcmp(argv[i],"--verify-config")) {
      newoptions->command = CMD_VERIFY_CONFIG;
    }
  }
  if (using_default_torrc) {
    /* didn't find one, try CONFDIR */
    const char *dflt = get_default_conf_file();
    if (dflt && file_status(dflt) == FN_FILE) {
      fname = tor_strdup(dflt);
    } else {
#ifndef MS_WINDOWS
      char *fn;
      fn = expand_filename("~/.torrc");
      if (fn && file_status(fn) == FN_FILE) {
        fname = fn;
      } else {
        tor_free(fn);
        fname = tor_strdup(dflt);
      }
#else
      fname = tor_strdup(dflt);
#endif
    }
  }
  tor_assert(fname);
  log(LOG_DEBUG, LD_CONFIG, "Opening config file \"%s\"", fname);

  tor_free(torrc_fname);
  torrc_fname = fname;

  /* get config lines, assign them */
  if (file_status(fname) != FN_FILE ||
      !(cf = read_file_to_str(fname,0,NULL))) {
    if (using_default_torrc == 1 || ignore_missing_torrc ) {
      log(LOG_NOTICE, LD_CONFIG, "Configuration file \"%s\" not present, "
          "using reasonable defaults.", fname);
      tor_free(fname); /* sets fname to NULL */
      torrc_fname = NULL;
    } else {
      log(LOG_WARN, LD_CONFIG,
          "Unable to open configuration file \"%s\".", fname);
      goto err;
    }
  } else { /* it opened successfully. use it. */
    retval = config_get_lines(cf, &cl);
    tor_free(cf);
    if (retval < 0)
      goto err;
    retval = config_assign(&options_format, newoptions, cl, 0, 0, &errmsg);
    config_free_lines(cl);
    if (retval < 0)
      goto err;
  }

  /* Go through command-line variables too */
  if (config_get_commandlines(argc, argv, &cl) < 0)
    goto err;
  retval = config_assign(&options_format, newoptions, cl, 0, 0, &errmsg);
  config_free_lines(cl);
  if (retval < 0)
    goto err;

  /* Validate newoptions */
  if (options_validate(oldoptions, newoptions, 0, &errmsg) < 0)
    goto err;

  if (options_transition_allowed(oldoptions, newoptions, &errmsg) < 0)
    goto err;

  if (set_options(newoptions, &errmsg))
    goto err; /* frees and replaces old options */

  return 0;
 err:
  tor_free(fname);
  torrc_fname = NULL;
  config_free(&options_format, newoptions);
  if (errmsg) {
    log(LOG_WARN,LD_CONFIG,"Failed to parse/validate config: %s", errmsg);
    tor_free(errmsg);
  }
  return -1;
}

/** Return the location for our configuration file.
 */
const char *
get_torrc_fname(void)
{
  if (torrc_fname)
    return torrc_fname;
  else
    return get_default_conf_file();
}

/** Adjust the address map mased on the MapAddress elements in the
 * configuration <b>options</b>
 */
static void
config_register_addressmaps(or_options_t *options)
{
  smartlist_t *elts;
  config_line_t *opt;
  char *from, *to;

  addressmap_clear_configured();
  elts = smartlist_create();
  for (opt = options->AddressMap; opt; opt = opt->next) {
    smartlist_split_string(elts, opt->value, NULL,
                           SPLIT_SKIP_SPACE|SPLIT_IGNORE_BLANK, 2);
    if (smartlist_len(elts) >= 2) {
      from = smartlist_get(elts,0);
      to = smartlist_get(elts,1);
      if (address_is_invalid_destination(to, 1)) {
        log_warn(LD_CONFIG,
                 "Skipping invalid argument '%s' to MapAddress", to);
      } else {
        addressmap_register(from, tor_strdup(to), 0);
        if (smartlist_len(elts)>2) {
          log_warn(LD_CONFIG,"Ignoring extra arguments to MapAddress.");
        }
      }
    } else {
      log_warn(LD_CONFIG,"MapAddress '%s' has too few arguments. Ignoring.",
               opt->value);
    }
    SMARTLIST_FOREACH(elts, char*, cp, tor_free(cp));
    smartlist_clear(elts);
  }
  smartlist_free(elts);
}

/** If <b>range</b> is of the form MIN-MAX, for MIN and MAX both
 * recognized log severity levels, set *<b>min_out</b> to MIN and
 * *<b>max_out</b> to MAX and return 0.  Else, if <b>range</b> is of
 * the form MIN, act as if MIN-err had been specified.  Else, warn and
 * return -1.
 */
static int
parse_log_severity_range(const char *range, int *min_out, int *max_out)
{
  int levelMin, levelMax;
  const char *cp;
  cp = strchr(range, '-');
  if (cp) {
    if (cp == range) {
      levelMin = LOG_DEBUG;
    } else {
      char *tmp_sev = tor_strndup(range, cp - range);
      levelMin = parse_log_level(tmp_sev);
      if (levelMin < 0) {
        log_warn(LD_CONFIG, "Unrecognized minimum log severity '%s': must be "
                 "one of err|warn|notice|info|debug", tmp_sev);
        tor_free(tmp_sev);
        return -1;
      }
      tor_free(tmp_sev);
    }
    if (!*(cp+1)) {
      levelMax = LOG_ERR;
    } else {
      levelMax = parse_log_level(cp+1);
      if (levelMax < 0) {
        log_warn(LD_CONFIG, "Unrecognized maximum log severity '%s': must be "
                 "one of err|warn|notice|info|debug", cp+1);
        return -1;
      }
    }
  } else {
    levelMin = parse_log_level(range);
    if (levelMin < 0) {
      log_warn(LD_CONFIG, "Unrecognized log severity '%s': must be one of "
               "err|warn|notice|info|debug", range);
      return -1;
    }
    levelMax = LOG_ERR;
  }

  *min_out = levelMin;
  *max_out = levelMax;

  return 0;
}

/**
 * Initialize the logs based on the configuration file.
 */
static int
options_init_logs(or_options_t *options, int validate_only)
{
  config_line_t *opt;
  int ok;
  smartlist_t *elts;
  int daemon =
#ifdef MS_WINDOWS
               0;
#else
               options->RunAsDaemon;
#endif

  ok = 1;
  elts = smartlist_create();

  for (opt = options->Logs; opt; opt = opt->next) {
    int levelMin=LOG_DEBUG, levelMax=LOG_ERR;
    smartlist_split_string(elts, opt->value, NULL,
                           SPLIT_SKIP_SPACE|SPLIT_IGNORE_BLANK, 3);
    if (smartlist_len(elts) == 0) {
      log_warn(LD_CONFIG, "No arguments to Log option 'Log %s'", opt->value);
      ok = 0; goto cleanup;
    }
    if (parse_log_severity_range(smartlist_get(elts,0), &levelMin,
                                 &levelMax)) {
      ok = 0; goto cleanup;
    }
    if (smartlist_len(elts) < 2) { /* only loglevels were provided */
      if (!validate_only) {
        if (daemon) {
          log_warn(LD_CONFIG,
              "Can't log to stdout with RunAsDaemon set; skipping stdout");
        } else {
          add_stream_log(levelMin, levelMax, "<stdout>", stdout);
        }
      }
      goto cleanup;
    }
    if (!strcasecmp(smartlist_get(elts,1), "file")) {
      if (smartlist_len(elts) != 3) {
        log_warn(LD_CONFIG, "Bad syntax on file Log option 'Log %s'",
                 opt->value);
        ok = 0; goto cleanup;
      }
      if (!validate_only) {
        if (add_file_log(levelMin, levelMax, smartlist_get(elts, 2)) < 0) {
          log_warn(LD_CONFIG, "Couldn't open file for 'Log %s'", opt->value);
          ok = 0;
        }
      }
      goto cleanup;
    }
    if (smartlist_len(elts) != 2) {
      log_warn(LD_CONFIG, "Wrong number of arguments on Log option 'Log %s'",
               opt->value);
      ok = 0; goto cleanup;
    }
    if (!strcasecmp(smartlist_get(elts,1), "stdout")) {
      if (daemon) {
        log_warn(LD_CONFIG, "Can't log to stdout with RunAsDaemon set.");
        ok = 0; goto cleanup;
      }
      if (!validate_only) {
        add_stream_log(levelMin, levelMax, "<stdout>", stdout);
      }
    } else if (!strcasecmp(smartlist_get(elts,1), "stderr")) {
      if (daemon) {
        log_warn(LD_CONFIG, "Can't log to stderr with RunAsDaemon set.");
        ok = 0; goto cleanup;
      }
      if (!validate_only) {
        add_stream_log(levelMin, levelMax, "<stderr>", stderr);
      }
    } else if (!strcasecmp(smartlist_get(elts,1), "syslog")) {
#ifdef HAVE_SYSLOG_H
      if (!validate_only)
        add_syslog_log(levelMin, levelMax);
#else
      log_warn(LD_CONFIG, "Syslog is not supported on this system. Sorry.");
#endif
    } else {
      log_warn(LD_CONFIG, "Unrecognized log type %s",
               (const char*)smartlist_get(elts,1));
      if (strchr(smartlist_get(elts,1), '/') ||
          strchr(smartlist_get(elts,1), '\\')) {
        log_warn(LD_CONFIG, "Did you mean to say 'Log %s file %s' ?",
                 (const char *)smartlist_get(elts,0),
                 (const char *)smartlist_get(elts,1));
      }
      ok = 0; goto cleanup;
    }
  cleanup:
    SMARTLIST_FOREACH(elts, char*, cp, tor_free(cp));
    smartlist_clear(elts);
  }
  smartlist_free(elts);

  return ok?0:-1;
}

/** Parse a single RedirectExit line's contents from <b>line</b>.  If
 *  they are valid, and <b>result</b> is not NULL, add an element to
 *  <b>result</b> and return 0. Else if they are valid, return 0.
 *  Else set *msg and return -1. */
static int
parse_redirect_line(smartlist_t *result, config_line_t *line, char **msg)
{
  smartlist_t *elements = NULL;
  exit_redirect_t *r;

  tor_assert(line);

  r = tor_malloc_zero(sizeof(exit_redirect_t));
  elements = smartlist_create();
  smartlist_split_string(elements, line->value, NULL,
                         SPLIT_SKIP_SPACE|SPLIT_IGNORE_BLANK, 0);
  if (smartlist_len(elements) != 2) {
    *msg = tor_strdup("Wrong number of elements in RedirectExit line");
    goto err;
  }
  if (parse_addr_and_port_range(smartlist_get(elements,0),&r->addr,
                                &r->maskbits,&r->port_min,&r->port_max)) {
    *msg = tor_strdup("Error parsing source address in RedirectExit line");
    goto err;
  }
  if (0==strcasecmp(smartlist_get(elements,1), "pass")) {
    r->is_redirect = 0;
  } else {
    if (parse_addr_port(LOG_WARN, smartlist_get(elements,1),NULL,
                        &r->addr_dest, &r->port_dest)) {
      *msg = tor_strdup("Error parsing dest address in RedirectExit line");
      goto err;
    }
    r->is_redirect = 1;
  }

  goto done;
 err:
  tor_free(r);
 done:
  SMARTLIST_FOREACH(elements, char *, cp, tor_free(cp));
  smartlist_free(elements);
  if (r) {
    if (result)
      smartlist_add(result, r);
    else
      tor_free(r);
    return 0;
  } else {
    tor_assert(*msg);
    return -1;
  }
}

/** Read the contents of a Bridge line from <b>line</b>. Return 0
 * if the line is well-formed, and -1 if it isn't. If
 * <b>validate_only</b> is 0, and the line is well-formed, then add
 * the bridge described in the line to our internal bridge list. */
static int
parse_bridge_line(const char *line, int validate_only)
{
  smartlist_t *items = NULL;
  int r;
  char *addrport=NULL, *address=NULL, *fingerprint=NULL;
  uint32_t addr = 0;
  uint16_t port = 0;
  char digest[DIGEST_LEN];

  items = smartlist_create();
  smartlist_split_string(items, line, NULL,
                         SPLIT_SKIP_SPACE|SPLIT_IGNORE_BLANK, -1);
  if (smartlist_len(items) < 1) {
    log_warn(LD_CONFIG, "Too few arguments to Bridge line.");
    goto err;
  }
  addrport = smartlist_get(items, 0);
  smartlist_del_keeporder(items, 0);
  if (parse_addr_port(LOG_WARN, addrport, &address, &addr, &port)<0) {
    log_warn(LD_CONFIG, "Error parsing Bridge address '%s'", addrport);
    goto err;
  }
  if (!port) {
    log_warn(LD_CONFIG, "Missing port in Bridge address '%s'",addrport);
    goto err;
  }

  if (smartlist_len(items)) {
    fingerprint = smartlist_join_strings(items, "", 0, NULL);
    if (strlen(fingerprint) != HEX_DIGEST_LEN) {
      log_warn(LD_CONFIG, "Key digest for Bridge is wrong length.");
      goto err;
    }
    if (base16_decode(digest, DIGEST_LEN, fingerprint, HEX_DIGEST_LEN)<0) {
      log_warn(LD_CONFIG, "Unable to decode Bridge key digest.");
      goto err;
    }
  }

  if (!validate_only) {
    log_debug(LD_DIR, "Bridge at %s:%d (%s)", address,
              (int)port,
              fingerprint ? fingerprint : "no key listed");
    bridge_add_from_config(addr, port, fingerprint ? digest : NULL);
  }

  r = 0;
  goto done;

  err:
  r = -1;

  done:
  SMARTLIST_FOREACH(items, char*, s, tor_free(s));
  smartlist_free(items);
  tor_free(addrport);
  tor_free(address);
  tor_free(fingerprint);
  return r;
}

/** Read the contents of a DirServer line from <b>line</b>.  Return 0
 * if the line is well-formed, and -1 if it isn't.  If
 * <b>validate_only</b> is 0, and the line is well-formed, then add
 * the dirserver described in the line as a valid authority. */
static int
parse_dir_server_line(const char *line, int validate_only)
{
  smartlist_t *items = NULL;
  int r;
  char *addrport=NULL, *address=NULL, *nickname=NULL, *fingerprint=NULL;
  uint16_t dir_port = 0, or_port = 0;
  char digest[DIGEST_LEN];
  char v3_digest[DIGEST_LEN];
  authority_type_t type = V2_AUTHORITY;
  int is_not_hidserv_authority = 0, is_not_v2_authority = 0;

  items = smartlist_create();
  smartlist_split_string(items, line, NULL,
                         SPLIT_SKIP_SPACE|SPLIT_IGNORE_BLANK, -1);
  if (smartlist_len(items) < 1) {
    log_warn(LD_CONFIG, "No arguments on DirServer line.");
    goto err;
  }

  if (is_legal_nickname(smartlist_get(items, 0))) {
    nickname = smartlist_get(items, 0);
    smartlist_del_keeporder(items, 0);
  }

  while (smartlist_len(items)) {
    char *flag = smartlist_get(items, 0);
    if (TOR_ISDIGIT(flag[0]))
      break;
    if (!strcasecmp(flag, "v1")) {
      type |= (V1_AUTHORITY | HIDSERV_AUTHORITY);
    } else if (!strcasecmp(flag, "hs")) {
      type |= HIDSERV_AUTHORITY;
    } else if (!strcasecmp(flag, "no-hs")) {
      is_not_hidserv_authority = 1;
    } else if (!strcasecmp(flag, "bridge")) {
      type |= BRIDGE_AUTHORITY;
    } else if (!strcasecmp(flag, "no-v2")) {
      is_not_v2_authority = 1;
    } else if (!strcasecmpstart(flag, "orport=")) {
      int ok;
      char *portstring = flag + strlen("orport=");
      or_port = (uint16_t) tor_parse_long(portstring, 10, 1, 65535, &ok, NULL);
      if (!ok)
        log_warn(LD_CONFIG, "Invalid orport '%s' on DirServer line.",
                 portstring);
    } else if (!strcasecmpstart(flag, "v3ident=")) {
      char *idstr = flag + strlen("v3ident=");
      if (strlen(idstr) != HEX_DIGEST_LEN ||
          base16_decode(v3_digest, DIGEST_LEN, idstr, HEX_DIGEST_LEN)<0) {
        log_warn(LD_CONFIG, "Bad v3 identity digest '%s' on DirServer line",
                 flag);
      } else {
        type |= V3_AUTHORITY;
      }
    } else {
      log_warn(LD_CONFIG, "Unrecognized flag '%s' on DirServer line",
               flag);
    }
    tor_free(flag);
    smartlist_del_keeporder(items, 0);
  }
  if (is_not_hidserv_authority)
    type &= ~HIDSERV_AUTHORITY;
  if (is_not_v2_authority)
    type &= ~V2_AUTHORITY;

  if (smartlist_len(items) < 2) {
    log_warn(LD_CONFIG, "Too few arguments to DirServer line.");
    goto err;
  }
  addrport = smartlist_get(items, 0);
  smartlist_del_keeporder(items, 0);
  if (parse_addr_port(LOG_WARN, addrport, &address, NULL, &dir_port)<0) {
    log_warn(LD_CONFIG, "Error parsing DirServer address '%s'", addrport);
    goto err;
  }
  if (!dir_port) {
    log_warn(LD_CONFIG, "Missing port in DirServer address '%s'",addrport);
    goto err;
  }

  fingerprint = smartlist_join_strings(items, "", 0, NULL);
  if (strlen(fingerprint) != HEX_DIGEST_LEN) {
    log_warn(LD_CONFIG, "Key digest for DirServer is wrong length %d.",
             (int)strlen(fingerprint));
    goto err;
  }
  if (!strcmp(fingerprint, "E623F7625FBE0C87820F11EC5F6D5377ED816294")) {
    /* a known bad fingerprint. refuse to use it. */
    log_warn(LD_CONFIG, "Dangerous dirserver line. To correct, erase your "
             "torrc file (%s), or reinstall Tor and use the default torrc.",
             get_torrc_fname());
    goto err;
  }
  if (base16_decode(digest, DIGEST_LEN, fingerprint, HEX_DIGEST_LEN)<0) {
    log_warn(LD_CONFIG, "Unable to decode DirServer key digest.");
    goto err;
  }

  if (!validate_only) {
    log_debug(LD_DIR, "Trusted dirserver at %s:%d (%s)", address,
              (int)dir_port,
              (char*)smartlist_get(items,0));
    add_trusted_dir_server(nickname, address, dir_port, or_port, digest,
                           v3_digest, type);
  }

  r = 0;
  goto done;

  err:
  r = -1;

  done:
  SMARTLIST_FOREACH(items, char*, s, tor_free(s));
  smartlist_free(items);
  tor_free(addrport);
  tor_free(address);
  tor_free(nickname);
  tor_free(fingerprint);
  return r;
}

/** Adjust the value of options->DataDirectory, or fill it in if it's
 * absent. Return 0 on success, -1 on failure. */
static int
normalize_data_directory(or_options_t *options)
{
#ifdef MS_WINDOWS
  char *p;
  if (options->DataDirectory)
    return 0; /* all set */
  p = tor_malloc(MAX_PATH);
  strlcpy(p,get_windows_conf_root(),MAX_PATH);
  options->DataDirectory = p;
  return 0;
#else
  const char *d = options->DataDirectory;
  if (!d)
    d = "~/.tor";

 if (strncmp(d,"~/",2) == 0) {
   char *fn = expand_filename(d);
   if (!fn) {
     log_warn(LD_CONFIG,"Failed to expand filename \"%s\".", d);
     return -1;
   }
   if (!options->DataDirectory && !strcmp(fn,"/.tor")) {
     /* If our homedir is /, we probably don't want to use it. */
     /* Default to LOCALSTATEDIR/tor which is probably closer to what we
      * want. */
     log_warn(LD_CONFIG,
              "Default DataDirectory is \"~/.tor\".  This expands to "
              "\"%s\", which is probably not what you want.  Using "
              "\"%s"PATH_SEPARATOR"tor\" instead", fn, LOCALSTATEDIR);
     tor_free(fn);
     fn = tor_strdup(LOCALSTATEDIR PATH_SEPARATOR "tor");
   }
   tor_free(options->DataDirectory);
   options->DataDirectory = fn;
 }
 return 0;
#endif
}

/** Check and normalize the value of options->DataDirectory; return 0 if it
 * sane, -1 otherwise. */
static int
validate_data_directory(or_options_t *options)
{
  if (normalize_data_directory(options) < 0)
    return -1;
  tor_assert(options->DataDirectory);
  if (strlen(options->DataDirectory) > (512-128)) {
    log_warn(LD_CONFIG, "DataDirectory is too long.");
    return -1;
  }
  return 0;
}

/** This string must remain the same forevermore. It is how we
 * recognize that the torrc file doesn't need to be backed up. */
#define GENERATED_FILE_PREFIX "# This file was generated by Tor; " \
  "if you edit it, comments will not be preserved"
/** This string can change; it tries to give the reader an idea
 * that editing this file by hand is not a good plan. */
#define GENERATED_FILE_COMMENT "# The old torrc file was renamed " \
  "to torrc.orig.1 or similar, and Tor will ignore it"

/** Save a configuration file for the configuration in <b>options</b>
 * into the file <b>fname</b>.  If the file already exists, and
 * doesn't begin with GENERATED_FILE_PREFIX, rename it.  Otherwise
 * replace it.  Return 0 on success, -1 on failure. */
static int
write_configuration_file(const char *fname, or_options_t *options)
{
  char *old_val=NULL, *new_val=NULL, *new_conf=NULL;
  int rename_old = 0, r;
  size_t len;

  if (fname) {
    switch (file_status(fname)) {
      case FN_FILE:
        old_val = read_file_to_str(fname, 0, NULL);
        if (strcmpstart(old_val, GENERATED_FILE_PREFIX)) {
          rename_old = 1;
        }
        tor_free(old_val);
        break;
      case FN_NOENT:
        break;
      case FN_ERROR:
      case FN_DIR:
      default:
        log_warn(LD_CONFIG,
                 "Config file \"%s\" is not a file? Failing.", fname);
        return -1;
    }
  }

  if (!(new_conf = options_dump(options, 1))) {
    log_warn(LD_BUG, "Couldn't get configuration string");
    goto err;
  }

  len = strlen(new_conf)+256;
  new_val = tor_malloc(len);
  tor_snprintf(new_val, len, "%s\n%s\n\n%s",
               GENERATED_FILE_PREFIX, GENERATED_FILE_COMMENT, new_conf);

  if (rename_old) {
    int i = 1;
    size_t fn_tmp_len = strlen(fname)+32;
    char *fn_tmp;
    tor_assert(fn_tmp_len > strlen(fname)); /*check for overflow*/
    fn_tmp = tor_malloc(fn_tmp_len);
    while (1) {
      if (tor_snprintf(fn_tmp, fn_tmp_len, "%s.orig.%d", fname, i)<0) {
        log_warn(LD_BUG, "tor_snprintf failed inexplicably");
        tor_free(fn_tmp);
        goto err;
      }
      if (file_status(fn_tmp) == FN_NOENT)
        break;
      ++i;
    }
    log_notice(LD_CONFIG, "Renaming old configuration file to \"%s\"", fn_tmp);
    if (rename(fname, fn_tmp) < 0) {
      log_warn(LD_FS,
               "Couldn't rename configuration file \"%s\" to \"%s\": %s",
               fname, fn_tmp, strerror(errno));
      tor_free(fn_tmp);
      goto err;
    }
    tor_free(fn_tmp);
  }

  if (write_str_to_file(fname, new_val, 0) < 0)
    goto err;

  r = 0;
  goto done;
 err:
  r = -1;
 done:
  tor_free(new_val);
  tor_free(new_conf);
  return r;
}

/**
 * Save the current configuration file value to disk.  Return 0 on
 * success, -1 on failure.
 **/
int
options_save_current(void)
{
  if (torrc_fname) {
    /* This fails if we can't write to our configuration file.
     *
     * If we try falling back to datadirectory or something, we have a better
     * chance of saving the configuration, but a better chance of doing
     * something the user never expected. Let's just warn instead. */
    return write_configuration_file(torrc_fname, get_options());
  }
  return write_configuration_file(get_default_conf_file(), get_options());
}

/** Mapping from a unit name to a multiplier for converting that unit into a
 * base unit. */
struct unit_table_t {
  const char *unit;
  uint64_t multiplier;
};

static struct unit_table_t memory_units[] = {
  { "",          1 },
  { "b",         1<< 0 },
  { "byte",      1<< 0 },
  { "bytes",     1<< 0 },
  { "kb",        1<<10 },
  { "kilobyte",  1<<10 },
  { "kilobytes", 1<<10 },
  { "m",         1<<20 },
  { "mb",        1<<20 },
  { "megabyte",  1<<20 },
  { "megabytes", 1<<20 },
  { "gb",        1<<30 },
  { "gigabyte",  1<<30 },
  { "gigabytes", 1<<30 },
  { "tb",        U64_LITERAL(1)<<40 },
  { "terabyte",  U64_LITERAL(1)<<40 },
  { "terabytes", U64_LITERAL(1)<<40 },
  { NULL, 0 },
};

static struct unit_table_t time_units[] = {
  { "",         1 },
  { "second",   1 },
  { "seconds",  1 },
  { "minute",   60 },
  { "minutes",  60 },
  { "hour",     60*60 },
  { "hours",    60*60 },
  { "day",      24*60*60 },
  { "days",     24*60*60 },
  { "week",     7*24*60*60 },
  { "weeks",    7*24*60*60 },
  { NULL, 0 },
};

/** Parse a string <b>val</b> containing a number, zero or more
 * spaces, and an optional unit string.  If the unit appears in the
 * table <b>u</b>, then multiply the number by the unit multiplier.
 * On success, set *<b>ok</b> to 1 and return this product.
 * Otherwise, set *<b>ok</b> to 0.
 */
static uint64_t
config_parse_units(const char *val, struct unit_table_t *u, int *ok)
{
  uint64_t v;
  char *cp;

  tor_assert(ok);

  v = tor_parse_uint64(val, 10, 0, UINT64_MAX, ok, &cp);
  if (!*ok)
    return 0;
  if (!cp) {
    *ok = 1;
    return v;
  }
  while (TOR_ISSPACE(*cp))
    ++cp;
  for ( ;u->unit;++u) {
    if (!strcasecmp(u->unit, cp)) {
      v *= u->multiplier;
      *ok = 1;
      return v;
    }
  }
  log_warn(LD_CONFIG, "Unknown unit '%s'.", cp);
  *ok = 0;
  return 0;
}

/** Parse a string in the format "number unit", where unit is a unit of
 * information (byte, KB, M, etc).  On success, set *<b>ok</b> to true
 * and return the number of bytes specified.  Otherwise, set
 * *<b>ok</b> to false and return 0. */
static uint64_t
config_parse_memunit(const char *s, int *ok)
{
  return config_parse_units(s, memory_units, ok);
}

/** Parse a string in the format "number unit", where unit is a unit of time.
 * On success, set *<b>ok</b> to true and return the number of seconds in
 * the provided interval.  Otherwise, set *<b>ok</b> to 0 and return -1.
 */
static int
config_parse_interval(const char *s, int *ok)
{
  uint64_t r;
  r = config_parse_units(s, time_units, ok);
  if (!ok)
    return -1;
  if (r > INT_MAX) {
    log_warn(LD_CONFIG, "Interval '%s' is too long", s);
    *ok = 0;
    return -1;
  }
  return (int)r;
}

/**
 * Initialize the libevent library.
 */
static void
init_libevent(void)
{
  configure_libevent_logging();
  /* If the kernel complains that some method (say, epoll) doesn't
   * exist, we don't care about it, since libevent will cope.
   */
  suppress_libevent_log_msg("Function not implemented");
#ifdef __APPLE__
  if (decode_libevent_version() < LE_11B) {
    setenv("EVENT_NOKQUEUE","1",1);
  }
#endif
  event_init();
  suppress_libevent_log_msg(NULL);
#if defined(HAVE_EVENT_GET_VERSION) && defined(HAVE_EVENT_GET_METHOD)
  /* Making this a NOTICE for now so we can link bugs to a libevent versions
   * or methods better. */
  log(LOG_NOTICE, LD_GENERAL,
      "Initialized libevent version %s using method %s. Good.",
      event_get_version(), event_get_method());
  check_libevent_version(event_get_method(), get_options()->ORPort != 0);
#else
  log(LOG_NOTICE, LD_GENERAL,
      "Initialized old libevent (version 1.0b or earlier).");
  log(LOG_WARN, LD_GENERAL,
      "You have a *VERY* old version of libevent.  It is likely to be buggy; "
      "please build Tor with a more recent version.");
#endif
}

#if defined(HAVE_EVENT_GET_VERSION) && defined(HAVE_EVENT_GET_METHOD)
/** Table mapping return value of event_get_version() to le_version_t. */
static const struct {
  const char *name; le_version_t version;
} le_version_table[] = {
  /* earlier versions don't have get_version. */
  { "1.0c", LE_10C },
  { "1.0d", LE_10D },
  { "1.0e", LE_10E },
  { "1.1",  LE_11 },
  { "1.1a", LE_11A },
  { "1.1b", LE_11B },
  { "1.2",  LE_12 },
  { "1.2a", LE_12A },
  { "1.3",  LE_13 },
  { "1.3a", LE_13A },
  { "1.3b", LE_13B },
  { "1.3c", LE_13C },
  { "1.3d", LE_13D },
  { NULL, LE_OTHER }
};

/** Return the le_version_t for the current version of libevent.  If the
 * version is very new, return LE_OTHER.  If the version is so old that it
 * doesn't support event_get_version(), return LE_OLD. */
static le_version_t
decode_libevent_version(void)
{
  const char *v = event_get_version();
  int i;
  for (i=0; le_version_table[i].name; ++i) {
    if (!strcmp(le_version_table[i].name, v)) {
      return le_version_table[i].version;
    }
  }
  return LE_OTHER;
}

/**
 * Compare the given libevent method and version to a list of versions
 * which are known not to work.  Warn the user as appropriate.
 */
static void
check_libevent_version(const char *m, int server)
{
  int buggy = 0, iffy = 0, slow = 0, thread_unsafe = 0;
  le_version_t version;
  const char *v = event_get_version();
  const char *badness = NULL;
  const char *sad_os = "";

  version = decode_libevent_version();

  /* XXX Would it be worthwhile disabling the methods that we know
   * are buggy, rather than just warning about them and then proceeding
   * to use them? If so, we should probably not wrap this whole thing
   * in HAVE_EVENT_GET_VERSION and HAVE_EVENT_GET_METHOD. -RD */
  /* XXXX The problem is that it's not trivial to get libevent to change it's
   * method once it's initialized, and it's not trivial to tell what method it
   * will use without initializing it.  I guess we could preemptively disable
   * buggy libevent modes based on the version _before_ initializing it,
   * though, but then there's no good way (afaict) to warn "I would have used
   * kqueue, but instead I'm using select." -NM */
  if (!strcmp(m, "kqueue")) {
    if (version < LE_11B)
      buggy = 1;
  } else if (!strcmp(m, "epoll")) {
    if (version < LE_11)
      iffy = 1;
  } else if (!strcmp(m, "poll")) {
    if (version < LE_10E)
      buggy = 1;
    else if (version < LE_11)
      slow = 1;
  } else if (!strcmp(m, "select")) {
    if (version < LE_11)
      slow = 1;
  } else if (!strcmp(m, "win32")) {
    if (version < LE_11B)
      buggy = 1;
  }

  /* Libevent versions before 1.3b do very badly on operating systems with
   * user-space threading implementations. */
#if defined(__OpenBSD__) || defined(__FreeBSD__) || defined(__NetBSD__)
  if (server && version < LE_13B) {
    thread_unsafe = 1;
    sad_os = "BSD variants";
  }
#elif defined(__APPLE__) || defined(__darwin__)
  if (server && version < LE_13B) {
    thread_unsafe = 1;
    sad_os = "Mac OS X";
  }
#endif

  if (thread_unsafe) {
    log(LOG_WARN, LD_GENERAL,
        "Libevent version %s often crashes when running a Tor server with %s. "
        "Please use the latest version of libevent (1.3b or later)",v,sad_os);
    badness = "BROKEN";
  } else if (buggy) {
    log(LOG_WARN, LD_GENERAL,
        "There are serious bugs in using %s with libevent %s. "
        "Please use the latest version of libevent.", m, v);
    badness = "BROKEN";
  } else if (iffy) {
    log(LOG_WARN, LD_GENERAL,
        "There are minor bugs in using %s with libevent %s. "
        "You may want to use the latest version of libevent.", m, v);
    badness = "BUGGY";
  } else if (slow && server) {
    log(LOG_WARN, LD_GENERAL,
        "libevent %s can be very slow with %s. "
        "When running a server, please use the latest version of libevent.",
        v,m);
    badness = "SLOW";
  }
  if (badness) {
    control_event_general_status(LOG_WARN,
        "BAD_LIBEVENT VERSION=%s METHOD=%s BADNESS=%s RECOVERED=NO",
                                 v, m, badness);
  }

}
#else
static le_version_t
decode_libevent_version(void)
{
  return LE_OLD;
}
#endif

/** Return the persistent state struct for this Tor. */
or_state_t *
get_or_state(void)
{
  tor_assert(global_state);
  return global_state;
}

/** Return a newly allocated string holding a filename relative to the data
 * directory.  If <b>sub1</b> is present, it is the first path component after
 * the data directory.  If <b>sub2</b> is also present, it is the second path
 * component after the data directory.  If <b>suffix</b> is present, it
 * is appended to the filename.
 *
 * Examples:
 *    get_datadir_fname2_suffix("a", NULL, NULL) -> $DATADIR/a
 *    get_datadir_fname2_suffix("a", NULL, ".tmp") -> $DATADIR/a.tmp
 *    get_datadir_fname2_suffix("a", "b", ".tmp") -> $DATADIR/a/b/.tmp
 *    get_datadir_fname2_suffix("a", "b", NULL) -> $DATADIR/a/b
 *
 * Note: Consider using the get_datadir_fname* macros in or.h.
 */
char *
get_datadir_fname2_suffix(const char *sub1, const char *sub2,
                          const char *suffix)
{
  or_options_t *options = get_options();
  char *fname = NULL;
  size_t len;
  tor_assert(options);
  tor_assert(options->DataDirectory);
  tor_assert(sub1 || !sub2); /* If sub2 is present, sub1 must be present. */
  len = strlen(options->DataDirectory);
  if (sub1) {
    len += strlen(sub1)+1;
    if (sub2)
      len += strlen(sub2)+1;
  }
  if (suffix)
    len += strlen(suffix);
  len++;
  fname = tor_malloc(len);
  if (sub1) {
    if (sub2) {
      tor_snprintf(fname, len, "%s"PATH_SEPARATOR"%s"PATH_SEPARATOR"%s",
                   options->DataDirectory, sub1, sub2);
    } else {
      tor_snprintf(fname, len, "%s"PATH_SEPARATOR"%s",
                   options->DataDirectory, sub1);
    }
  } else {
    strlcpy(fname, options->DataDirectory, len);
  }
  if (suffix)
    strlcat(fname, suffix, len);
  return fname;
}

/** Return 0 if every setting in <b>state</b> is reasonable, and a
 * permissible transition from <b>old_state</b>.  Else warn and return -1.
 * Should have no side effects, except for normalizing the contents of
 * <b>state</b>.
 */
/* XXX from_setconf is here because of bug 238 */
static int
or_state_validate(or_state_t *old_state, or_state_t *state,
                  int from_setconf, char **msg)
{
  /* We don't use these; only options do. Still, we need to match that
   * signature. */
  (void) from_setconf;
  (void) old_state;

  if (entry_guards_parse_state(state, 0, msg)<0)
    return -1;

  return 0;
}

/** Replace the current persistent state with <b>new_state</b> */
static void
or_state_set(or_state_t *new_state)
{
  char *err = NULL;
  tor_assert(new_state);
  if (global_state)
    config_free(&state_format, global_state);
  global_state = new_state;
  if (entry_guards_parse_state(global_state, 1, &err)<0) {
    log_warn(LD_GENERAL,"%s",err);
    tor_free(err);
  }
  if (rep_hist_load_state(global_state, &err)<0) {
    log_warn(LD_GENERAL,"Unparseable bandwidth history state: %s",err);
    tor_free(err);
  }
}

/** Reload the persistent state from disk, generating a new state as needed.
 * Return 0 on success, less than 0 on failure.
 */
static int
or_state_load(void)
{
  or_state_t *new_state = NULL;
  char *contents = NULL, *fname;
  char *errmsg = NULL;
  int r = -1, badstate = 0;

  fname = get_datadir_fname("state");
  switch (file_status(fname)) {
    case FN_FILE:
      if (!(contents = read_file_to_str(fname, 0, NULL))) {
        log_warn(LD_FS, "Unable to read state file \"%s\"", fname);
        goto done;
      }
      break;
    case FN_NOENT:
      break;
    case FN_ERROR:
    case FN_DIR:
    default:
      log_warn(LD_GENERAL,"State file \"%s\" is not a file? Failing.", fname);
      goto done;
  }
  new_state = tor_malloc_zero(sizeof(or_state_t));
  new_state->_magic = OR_STATE_MAGIC;
  config_init(&state_format, new_state);
  if (contents) {
    config_line_t *lines=NULL;
    int assign_retval;
    if (config_get_lines(contents, &lines)<0)
      goto done;
    assign_retval = config_assign(&state_format, new_state,
                                  lines, 0, 0, &errmsg);
    config_free_lines(lines);
    if (assign_retval<0)
      badstate = 1;
    if (errmsg) {
      log_warn(LD_GENERAL, "%s", errmsg);
      tor_free(errmsg);
    }
  }

  if (!badstate && or_state_validate(NULL, new_state, 1, &errmsg) < 0)
    badstate = 1;

  if (errmsg) {
    log_warn(LD_GENERAL, "%s", errmsg);
    tor_free(errmsg);
  }

  if (badstate && !contents) {
    log_warn(LD_BUG, "Uh oh.  We couldn't even validate our own default state."
             " This is a bug in Tor.");
    goto done;
  } else if (badstate && contents) {
    int i;
    file_status_t status;
    size_t len = strlen(fname)+16;
    char *fname2 = tor_malloc(len);
    for (i = 0; i < 100; ++i) {
      tor_snprintf(fname2, len, "%s.%d", fname, i);
      status = file_status(fname2);
      if (status == FN_NOENT)
        break;
    }
    if (i == 100) {
      log_warn(LD_BUG, "Unable to parse state in \"%s\"; too many saved bad "
               "state files to move aside. Discarding the old state file.",
               fname);
      unlink(fname);
    } else {
      log_warn(LD_BUG, "Unable to parse state in \"%s\". Moving it aside "
               "to \"%s\".  This could be a bug in Tor; please tell "
               "the developers.", fname, fname2);
      rename(fname, fname2);
    }
    tor_free(fname2);
    tor_free(contents);
    config_free(&state_format, new_state);

    new_state = tor_malloc_zero(sizeof(or_state_t));
    new_state->_magic = OR_STATE_MAGIC;
    config_init(&state_format, new_state);
  } else if (contents) {
    log_info(LD_GENERAL, "Loaded state from \"%s\"", fname);
  } else {
    log_info(LD_GENERAL, "Initialized state");
  }
  or_state_set(new_state);
  new_state = NULL;
  if (!contents) {
    global_state->next_write = 0;
    or_state_save(time(NULL));
  }
  r = 0;

 done:
  tor_free(fname);
  tor_free(contents);
  if (new_state)
    config_free(&state_format, new_state);

  return r;
}

/** Write the persistent state to disk. Return 0 for success, <0 on failure. */
int
or_state_save(time_t now)
{
  char *state, *contents;
  char tbuf[ISO_TIME_LEN+1];
  size_t len;
  char *fname;

  tor_assert(global_state);

  if (global_state->next_write > now)
    return 0;

  /* Call everything else that might dirty the state even more, in order
   * to avoid redundant writes. */
  entry_guards_update_state(global_state);
  rep_hist_update_state(global_state);
  if (accounting_is_enabled(get_options()))
    accounting_run_housekeeping(now);

  global_state->LastWritten = time(NULL);
  tor_free(global_state->TorVersion);
  len = strlen(get_version())+8;
  global_state->TorVersion = tor_malloc(len);
  tor_snprintf(global_state->TorVersion, len, "Tor %s", get_version());

  state = config_dump(&state_format, global_state, 1, 0);
  len = strlen(state)+256;
  contents = tor_malloc(len);
  format_local_iso_time(tbuf, time(NULL));
  tor_snprintf(contents, len,
               "# Tor state file last generated on %s local time\n"
               "# Other times below are in GMT\n"
               "# You *do not* need to edit this file.\n\n%s",
               tbuf, state);
  tor_free(state);
  fname = get_datadir_fname("state");
  if (write_str_to_file(fname, contents, 0)<0) {
    log_warn(LD_FS, "Unable to write state to file \"%s\"", fname);
    tor_free(fname);
    tor_free(contents);
    return -1;
  }
  log_info(LD_GENERAL, "Saved state to \"%s\"", fname);
  tor_free(fname);
  tor_free(contents);

  global_state->next_write = TIME_MAX;
  return 0;
}

/** Given a file name check to see whether the file exists but has not been
 * modified for a very long time.  If so, remove it. */
void
remove_file_if_very_old(const char *fname, time_t now)
{
#define VERY_OLD_FILE_AGE (28*24*60*60)
  struct stat st;

  if (stat(fname, &st)==0 && st.st_mtime < now-VERY_OLD_FILE_AGE) {
    char buf[ISO_TIME_LEN+1];
    format_local_iso_time(buf, st.st_mtime);
    log_notice(LD_GENERAL, "Obsolete file %s hasn't been modified since %s. "
               "Removing it.", fname, buf);
    unlink(fname);
  }
}

/** Helper to implement GETINFO functions about configuration variables (not
 * their values).  Given a "config/names" question, set *<b>answer</b> to a
 * new string describing the supported configuration variables and their
 * types. */
int
getinfo_helper_config(control_connection_t *conn,
                      const char *question, char **answer)
{
  (void) conn;
  if (!strcmp(question, "config/names")) {
    smartlist_t *sl = smartlist_create();
    int i;
    for (i = 0; _option_vars[i].name; ++i) {
      config_var_t *var = &_option_vars[i];
      const char *type, *desc;
      char *line;
      size_t len;
      desc = config_find_description(&options_format, var->name);
      switch (var->type) {
        case CONFIG_TYPE_STRING: type = "String"; break;
        case CONFIG_TYPE_UINT: type = "Integer"; break;
        case CONFIG_TYPE_INTERVAL: type = "TimeInterval"; break;
        case CONFIG_TYPE_MEMUNIT: type = "DataSize"; break;
        case CONFIG_TYPE_DOUBLE: type = "Float"; break;
        case CONFIG_TYPE_BOOL: type = "Boolean"; break;
        case CONFIG_TYPE_ISOTIME: type = "Time"; break;
        case CONFIG_TYPE_CSV: type = "CommaList"; break;
        case CONFIG_TYPE_LINELIST: type = "LineList"; break;
        case CONFIG_TYPE_LINELIST_S: type = "Dependant"; break;
        case CONFIG_TYPE_LINELIST_V: type = "Virtual"; break;
        default:
        case CONFIG_TYPE_OBSOLETE:
          type = NULL; break;
      }
      if (!type)
        continue;
      len = strlen(var->name)+strlen(type)+16;
      if (desc)
        len += strlen(desc);
      line = tor_malloc(len);
      if (desc)
        tor_snprintf(line, len, "%s %s %s\n",var->name,type,desc);
      else
        tor_snprintf(line, len, "%s %s\n",var->name,type);
      smartlist_add(sl, line);
    }
    *answer = smartlist_join_strings(sl, "", 0, NULL);
    SMARTLIST_FOREACH(sl, char *, c, tor_free(c));
    smartlist_free(sl);
  }
  return 0;
}

#include "aes.h"
#include "ht.h"
#include "test.h"

extern const char aes_c_id[];
extern const char compat_c_id[];
extern const char container_c_id[];
extern const char crypto_c_id[];
extern const char log_c_id[];
extern const char torgzip_c_id[];
extern const char tortls_c_id[];
extern const char util_c_id[];

extern const char buffers_c_id[];
extern const char circuitbuild_c_id[];
extern const char circuitlist_c_id[];
extern const char circuituse_c_id[];
extern const char command_c_id[];
//  extern const char config_c_id[];
extern const char connection_c_id[];
extern const char connection_edge_c_id[];
extern const char connection_or_c_id[];
extern const char control_c_id[];
extern const char cpuworker_c_id[];
extern const char directory_c_id[];
extern const char dirserv_c_id[];
extern const char dns_c_id[];
extern const char hibernate_c_id[];
extern const char main_c_id[];
#ifdef NT_SERVICE
extern const char ntmain_c_id[];
#endif
extern const char onion_c_id[];
extern const char policies_c_id[];
extern const char relay_c_id[];
extern const char rendclient_c_id[];
extern const char rendcommon_c_id[];
extern const char rendmid_c_id[];
extern const char rendservice_c_id[];
extern const char rephist_c_id[];
extern const char router_c_id[];
extern const char routerlist_c_id[];
extern const char routerparse_c_id[];

/** Dump the version of every file to the log. */
static void
print_svn_version(void)
{
  puts(AES_H_ID);
  puts(COMPAT_H_ID);
  puts(CONTAINER_H_ID);
  puts(CRYPTO_H_ID);
  puts(HT_H_ID);
  puts(TEST_H_ID);
  puts(LOG_H_ID);
  puts(TORGZIP_H_ID);
  puts(TORINT_H_ID);
  puts(TORTLS_H_ID);
  puts(UTIL_H_ID);
  puts(aes_c_id);
  puts(compat_c_id);
  puts(container_c_id);
  puts(crypto_c_id);
  puts(log_c_id);
  puts(torgzip_c_id);
  puts(tortls_c_id);
  puts(util_c_id);

  puts(OR_H_ID);
  puts(buffers_c_id);
  puts(circuitbuild_c_id);
  puts(circuitlist_c_id);
  puts(circuituse_c_id);
  puts(command_c_id);
  puts(config_c_id);
  puts(connection_c_id);
  puts(connection_edge_c_id);
  puts(connection_or_c_id);
  puts(control_c_id);
  puts(cpuworker_c_id);
  puts(directory_c_id);
  puts(dirserv_c_id);
  puts(dns_c_id);
  puts(hibernate_c_id);
  puts(main_c_id);
#ifdef NT_SERVICE
  puts(ntmain_c_id);
#endif
  puts(onion_c_id);
  puts(policies_c_id);
  puts(relay_c_id);
  puts(rendclient_c_id);
  puts(rendcommon_c_id);
  puts(rendmid_c_id);
  puts(rendservice_c_id);
  puts(rephist_c_id);
  puts(router_c_id);
  puts(routerlist_c_id);
  puts(routerparse_c_id);
}