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- /* Copyright (c) 2001 Matej Pfajfar.
- * Copyright (c) 2001-2004, Roger Dingledine.
- * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
- * Copyright (c) 2007-2019, The Tor Project, Inc. */
- /* See LICENSE for licensing information */
- /**
- * @file structvar.c
- * @brief Functions to manipulate named and typed elements of
- * a structure.
- *
- * These functions represent a low-level API for accessing a member of a
- * structure. They use typedvar.c to work, and they are used in turn by the
- * configuration system to examine and set fields in configuration objects
- * used by individual modules.
- *
- * Almost no code should call these directly.
- **/
- #include "orconfig.h"
- #include "lib/confmgt/structvar.h"
- #include "lib/cc/compat_compiler.h"
- #include "lib/conf/conftypes.h"
- #include "lib/confmgt/type_defs.h"
- #include "lib/confmgt/typedvar.h"
- #include "lib/log/util_bug.h"
- #include "lib/confmgt/var_type_def_st.h"
- #include <stddef.h>
- /**
- * Set the 'magic number' on <b>object</b> to correspond to decl.
- **/
- void
- struct_set_magic(void *object, const struct_magic_decl_t *decl)
- {
- tor_assert(object);
- tor_assert(decl);
- uint32_t *ptr = STRUCT_VAR_P(object, decl->magic_offset);
- *ptr = decl->magic_val;
- }
- /**
- * Assert that the 'magic number' on <b>object</b> to corresponds to decl.
- **/
- void
- struct_check_magic(const void *object, const struct_magic_decl_t *decl)
- {
- tor_assert(object);
- tor_assert(decl);
- const uint32_t *ptr = STRUCT_VAR_P(object, decl->magic_offset);
- tor_assertf(*ptr == decl->magic_val,
- "Bad magic number on purported %s object. "
- "Expected %"PRIu32"x but got "PRIu32"x.",
- decl->magic_val, *ptr);
- }
- /**
- * Return a mutable pointer to the member of <b>object</b> described
- * by <b>member</b>.
- **/
- void *
- struct_get_mptr(void *object, const struct_member_t *member)
- {
- tor_assert(object);
- return STRUCT_VAR_P(object, member->offset);
- }
- /**
- * Return a const pointer to the member of <b>object</b> described
- * by <b>member</b>.
- **/
- const void *
- struct_get_ptr(const void *object, const struct_member_t *member)
- {
- tor_assert(object);
- return STRUCT_VAR_P(object, member->offset);
- }
- /**
- * Helper: given a struct_member_t, look up the type definition for its
- * variable.
- */
- static const var_type_def_t *
- get_type_def(const struct_member_t *member)
- {
- if (member->type_def)
- return member->type_def;
- return lookup_type_def(member->type);
- }
- /**
- * (As typed_var_free, but free and clear the member of <b>object</b> defined
- * by <b>member</b>.)
- **/
- void
- struct_var_free(void *object, const struct_member_t *member)
- {
- void *p = struct_get_mptr(object, member);
- const var_type_def_t *def = get_type_def(member);
- typed_var_free(p, def);
- }
- /**
- * (As typed_var_copy, but copy from <b>src</b> to <b>dest</b> the member
- * defined by <b>member</b>.)
- **/
- int
- struct_var_copy(void *dest, const void *src, const struct_member_t *member)
- {
- void *p_dest = struct_get_mptr(dest, member);
- const void *p_src = struct_get_ptr(src, member);
- const var_type_def_t *def = get_type_def(member);
- return typed_var_copy(p_dest, p_src, def);
- }
- /**
- * (As typed_var_eq, but compare the members of <b>a</b> and <b>b</b>
- * defined by <b>member</b>.)
- **/
- bool
- struct_var_eq(const void *a, const void *b, const struct_member_t *member)
- {
- const void *p_a = struct_get_ptr(a, member);
- const void *p_b = struct_get_ptr(b, member);
- const var_type_def_t *def = get_type_def(member);
- return typed_var_eq(p_a, p_b, def);
- }
- /**
- * (As typed_var_ok, but validate the member of <b>object</b> defined by
- * <b>member</b>.)
- **/
- bool
- struct_var_ok(const void *object, const struct_member_t *member)
- {
- const void *p = struct_get_ptr(object, member);
- const var_type_def_t *def = get_type_def(member);
- return typed_var_ok(p, def);
- }
- /**
- * (As typed_var_kvassign, but assign a value to the member of <b>object</b>
- * defined by <b>member</b>.)
- **/
- int
- struct_var_kvassign(void *object, const struct config_line_t *line,
- char **errmsg,
- const struct_member_t *member)
- {
- void *p = struct_get_mptr(object, member);
- const var_type_def_t *def = get_type_def(member);
- return typed_var_kvassign(p, line, errmsg, def);
- }
- /**
- * (As typed_var_kvencode, but encode the value of the member of <b>object</b>
- * defined by <b>member</b>.)
- **/
- struct config_line_t *
- struct_var_kvencode(const void *object, const struct_member_t *member)
- {
- const void *p = struct_get_ptr(object, member);
- const var_type_def_t *def = get_type_def(member);
- return typed_var_kvencode(member->name, p, def);
- }
- /**
- * Mark the field in <b>object</b> determined by <b>member</b> -- a variable
- * that ordinarily would be extended by assignment -- as "fragile", so that it
- * will get replaced by the next assignment instead.
- */
- void
- struct_var_mark_fragile(void *object, const struct_member_t *member)
- {
- void *p = struct_get_mptr(object, member);
- const var_type_def_t *def = get_type_def(member);
- return typed_var_mark_fragile(p, def);
- }
- /**
- * Return the official name of this struct member.
- **/
- const char *
- struct_var_get_name(const struct_member_t *member)
- {
- return member->name;
- }
- /**
- * Return the type name for this struct member.
- *
- * Do not use the output of this function to inspect a type within Tor. It is
- * suitable for debugging, informing the controller or user of a variable's
- * type, etc.
- **/
- const char *
- struct_var_get_typename(const struct_member_t *member)
- {
- const var_type_def_t *def = get_type_def(member);
- return def ? def->name : NULL;
- }
- /** Return all of the flags set for this struct member. */
- uint32_t
- struct_var_get_flags(const struct_member_t *member)
- {
- const var_type_def_t *def = get_type_def(member);
- return def ? def->flags : 0;
- }
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