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- /* Copyright (c) 2003-2004, Roger Dingledine
- * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
- * Copyright (c) 2007-2019, The Tor Project, Inc. */
- /* See LICENSE for licensing information */
- /**
- * \file env.c
- * \brief Inspect and manipulate the environment variables.
- **/
- #include "orconfig.h"
- #include "lib/process/env.h"
- #include "lib/malloc/malloc.h"
- #include "lib/ctime/di_ops.h"
- #include "lib/container/smartlist.h"
- #include "lib/log/util_bug.h"
- #include "lib/log/log.h"
- #include "lib/malloc/malloc.h"
- #ifdef HAVE_UNISTD_H
- #include <unistd.h>
- #endif
- #include <stdlib.h>
- #include <string.h>
- #ifdef HAVE_CRT_EXTERNS_H
- /* For _NSGetEnviron on macOS */
- #include <crt_externs.h>
- #endif
- #ifndef HAVE__NSGETENVIRON
- #ifndef HAVE_EXTERN_ENVIRON_DECLARED
- /* Some platforms declare environ under some circumstances, others don't. */
- #ifndef RUNNING_DOXYGEN
- extern char **environ;
- #endif
- #endif /* !defined(HAVE_EXTERN_ENVIRON_DECLARED) */
- #endif /* !defined(HAVE__NSGETENVIRON) */
- /** Return the current environment. This is a portable replacement for
- * 'environ'. */
- char **
- get_environment(void)
- {
- #ifdef HAVE__NSGETENVIRON
- /* This is for compatibility between OSX versions. Otherwise (for example)
- * when we do a mostly-static build on OSX 10.7, the resulting binary won't
- * work on OSX 10.6. */
- return *_NSGetEnviron();
- #else /* !(defined(HAVE__NSGETENVIRON)) */
- return environ;
- #endif /* defined(HAVE__NSGETENVIRON) */
- }
- /** Helper: return the number of characters in <b>s</b> preceding the first
- * occurrence of <b>ch</b>. If <b>ch</b> does not occur in <b>s</b>, return
- * the length of <b>s</b>. Should be equivalent to strspn(s, "ch"). */
- static inline size_t
- str_num_before(const char *s, char ch)
- {
- const char *cp = strchr(s, ch);
- if (cp)
- return cp - s;
- else
- return strlen(s);
- }
- /** Return non-zero iff getenv would consider <b>s1</b> and <b>s2</b>
- * to have the same name as strings in a process's environment. */
- int
- environment_variable_names_equal(const char *s1, const char *s2)
- {
- size_t s1_name_len = str_num_before(s1, '=');
- size_t s2_name_len = str_num_before(s2, '=');
- return (s1_name_len == s2_name_len &&
- tor_memeq(s1, s2, s1_name_len));
- }
- /** Free <b>env</b> (assuming it was produced by
- * process_environment_make). */
- void
- process_environment_free_(process_environment_t *env)
- {
- if (env == NULL) return;
- /* As both an optimization hack to reduce consing on Unixoid systems
- * and a nice way to ensure that some otherwise-Windows-specific
- * code will always get tested before changes to it get merged, the
- * strings which env->unixoid_environment_block points to are packed
- * into env->windows_environment_block. */
- tor_free(env->unixoid_environment_block);
- tor_free(env->windows_environment_block);
- tor_free(env);
- }
- /** Make a process_environment_t containing the environment variables
- * specified in <b>env_vars</b> (as C strings of the form
- * "NAME=VALUE"). */
- process_environment_t *
- process_environment_make(struct smartlist_t *env_vars)
- {
- process_environment_t *env = tor_malloc_zero(sizeof(process_environment_t));
- int n_env_vars = smartlist_len(env_vars);
- int i;
- size_t total_env_length;
- smartlist_t *env_vars_sorted;
- tor_assert(n_env_vars + 1 != 0);
- env->unixoid_environment_block = tor_calloc(n_env_vars + 1, sizeof(char *));
- /* env->unixoid_environment_block is already NULL-terminated,
- * because we assume that NULL == 0 (and check that during compilation). */
- total_env_length = 1; /* terminating NUL of terminating empty string */
- for (i = 0; i < n_env_vars; ++i) {
- const char *s = smartlist_get(env_vars, (int)i);
- size_t slen = strlen(s);
- tor_assert(slen + 1 != 0);
- tor_assert(slen + 1 < SIZE_MAX - total_env_length);
- total_env_length += slen + 1;
- }
- env->windows_environment_block = tor_malloc_zero(total_env_length);
- /* env->windows_environment_block is already
- * (NUL-terminated-empty-string)-terminated. */
- /* Some versions of Windows supposedly require that environment
- * blocks be sorted. Or maybe some Windows programs (or their
- * runtime libraries) fail to look up strings in non-sorted
- * environment blocks.
- *
- * Also, sorting strings makes it easy to find duplicate environment
- * variables and environment-variable strings without an '=' on all
- * OSes, and they can cause badness. Let's complain about those. */
- env_vars_sorted = smartlist_new();
- smartlist_add_all(env_vars_sorted, env_vars);
- smartlist_sort_strings(env_vars_sorted);
- /* Now copy the strings into the environment blocks. */
- {
- char *cp = env->windows_environment_block;
- const char *prev_env_var = NULL;
- for (i = 0; i < n_env_vars; ++i) {
- const char *s = smartlist_get(env_vars_sorted, (int)i);
- size_t slen = strlen(s);
- size_t s_name_len = str_num_before(s, '=');
- if (s_name_len == slen) {
- log_warn(LD_GENERAL,
- "Preparing an environment containing a variable "
- "without a value: %s",
- s);
- }
- if (prev_env_var != NULL &&
- environment_variable_names_equal(s, prev_env_var)) {
- log_warn(LD_GENERAL,
- "Preparing an environment containing two variables "
- "with the same name: %s and %s",
- prev_env_var, s);
- }
- prev_env_var = s;
- /* Actually copy the string into the environment. */
- memcpy(cp, s, slen+1);
- env->unixoid_environment_block[i] = cp;
- cp += slen+1;
- }
- tor_assert(cp == env->windows_environment_block + total_env_length - 1);
- }
- smartlist_free(env_vars_sorted);
- return env;
- }
- /** Return a newly allocated smartlist containing every variable in
- * this process's environment, as a NUL-terminated string of the form
- * "NAME=VALUE". Note that on some/many/most/all OSes, the parent
- * process can put strings not of that form in our environment;
- * callers should try to not get crashed by that.
- *
- * The returned strings are heap-allocated, and must be freed by the
- * caller. */
- struct smartlist_t *
- get_current_process_environment_variables(void)
- {
- smartlist_t *sl = smartlist_new();
- char **environ_tmp; /* Not const char ** ? Really? */
- for (environ_tmp = get_environment(); *environ_tmp; ++environ_tmp) {
- smartlist_add_strdup(sl, *environ_tmp);
- }
- return sl;
- }
- /** For each string s in <b>env_vars</b> such that
- * environment_variable_names_equal(s, <b>new_var</b>), remove it; if
- * <b>free_p</b> is non-zero, call <b>free_old</b>(s). If
- * <b>new_var</b> contains '=', insert it into <b>env_vars</b>. */
- void
- set_environment_variable_in_smartlist(struct smartlist_t *env_vars,
- const char *new_var,
- void (*free_old)(void*),
- int free_p)
- {
- SMARTLIST_FOREACH_BEGIN(env_vars, const char *, s) {
- if (environment_variable_names_equal(s, new_var)) {
- SMARTLIST_DEL_CURRENT(env_vars, s);
- if (free_p) {
- free_old((void *)s);
- }
- }
- } SMARTLIST_FOREACH_END(s);
- if (strchr(new_var, '=') != NULL) {
- smartlist_add(env_vars, (void *)new_var);
- }
- }
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