config.c

关于tor匿名通信的源代码

  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;
/** Configuration Options set by command line. */
static config_line_t *global_cmdline_options = 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.  Returns 0 on success, -1 on failure.
 */
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;
  }
  if (global_cmdline_options) {
    config_free_lines(global_cmdline_options);
    global_cmdline_options = 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 authorities directly into the trusted dir list,
 * but only add them insofar as they share bits with <b>type</b>. */
static void
add_default_trusted_dir_authorities(authority_type_t type)
{
  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 orport=443 v3ident=E8A9C45EDE6D711294FADF8E7951F4DE6CA56B58 "
      "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",
    "ides orport=9090 no-v2 v3ident=27B6B5996C426270A5C95488AA5BCEB6BCC86956 "
      "216.224.124.114:9030 F397 038A DC51 3361 35E7 B80B D99C A384 4360 292B",
    "gabelmoo orport=443 no-v2 "
      "v3ident=EAA879B5C75032E462CB018630D2D0DF46EBA606 "
      "88.198.7.215:80 6833 3D07 61BC F397 A587 A0C0 B963 E4A9 E99E C4D3",
    "dannenberg orport=443 no-v2 "
      "v3ident=585769C78764D58426B8B52B6651A5A71137189A "
      "213.73.91.31:80 7BE6 83E6 5D48 1413 21C5 ED92 F075 C553 64AC 7123",
    NULL
  };
  for (i=0; dirservers[i]; i++) {
    if (parse_dir_server_line(dirservers[i], type, 0)<0) {
      log_err(LD_BUG, "Couldn't parse internal dirserver line %s",
              dirservers[i]);
    }
  }
}

/** Look at all the config options for using alternate directory
 * authorities, and make sure none of them are broken. Also, warn the
 * user if we changed any dangerous ones.
 */
static int
validate_dir_authorities(or_options_t *options, or_options_t *old_options)
{
  config_line_t *cl;

  if (options->DirServers &&
      (options->AlternateDirAuthority || options->AlternateBridgeAuthority ||
       options->AlternateHSAuthority)) {
    log_warn(LD_CONFIG,
             "You cannot set both DirServers and Alternate*Authority.");
    return -1;
  }

  /* do we want to complain to the user about being partitionable? */
  if ((options->DirServers &&
       (!old_options ||
        !config_lines_eq(options->DirServers, old_options->DirServers))) ||
      (options->AlternateDirAuthority &&
       (!old_options ||
        !config_lines_eq(options->AlternateDirAuthority,
                         old_options->AlternateDirAuthority)))) {
    log_warn(LD_CONFIG,
             "You have used DirServer or AlternateDirAuthority to "
             "specify alternate 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.");
  }

  /* Now go through the four ways you can configure an alternate
   * set of directory authorities, and make sure none are broken. */
  for (cl = options->DirServers; cl; cl = cl->next)
    if (parse_dir_server_line(cl->value, NO_AUTHORITY, 1)<0)
      return -1;
  for (cl = options->AlternateBridgeAuthority; cl; cl = cl->next)
    if (parse_dir_server_line(cl->value, NO_AUTHORITY, 1)<0)
      return -1;
  for (cl = options->AlternateDirAuthority; cl; cl = cl->next)
    if (parse_dir_server_line(cl->value, NO_AUTHORITY, 1)<0)
      return -1;
  for (cl = options->AlternateHSAuthority; cl; cl = cl->next)
    if (parse_dir_server_line(cl->value, NO_AUTHORITY, 1)<0)
      return -1;
  return 0;
}

/** Look at all the config options and assign new dir authorities
 * as appropriate.
 */
static int
consider_adding_dir_authorities(or_options_t *options,
                                or_options_t *old_options)
{
  config_line_t *cl;
  int need_to_update =
    !smartlist_len(router_get_trusted_dir_servers()) || !old_options ||
    !config_lines_eq(options->DirServers, old_options->DirServers) ||
    !config_lines_eq(options->AlternateBridgeAuthority,
                     old_options->AlternateBridgeAuthority) ||
    !config_lines_eq(options->AlternateDirAuthority,
                     old_options->AlternateDirAuthority) ||
    !config_lines_eq(options->AlternateHSAuthority,
                     old_options->AlternateHSAuthority);

  if (!need_to_update)
    return 0; /* all done */

  /* Start from a clean slate. */
  clear_trusted_dir_servers();

  if (!options->DirServers) {
    /* then we may want some of the defaults */
    authority_type_t type = NO_AUTHORITY;
    if (!options->AlternateBridgeAuthority)
      type |= BRIDGE_AUTHORITY;
    if (!options->AlternateDirAuthority)
      type |= V1_AUTHORITY | V2_AUTHORITY | V3_AUTHORITY;
    if (!options->AlternateHSAuthority)
      type |= HIDSERV_AUTHORITY;
    add_default_trusted_dir_authorities(type);
  }

  for (cl = options->DirServers; cl; cl = cl->next)
    if (parse_dir_server_line(cl->value, NO_AUTHORITY, 0)<0)
      return -1;
  for (cl = options->AlternateBridgeAuthority; cl; cl = cl->next)
    if (parse_dir_server_line(cl->value, NO_AUTHORITY, 0)<0)
      return -1;
  for (cl = options->AlternateDirAuthority; cl; cl = cl->next)
    if (parse_dir_server_line(cl->value, NO_AUTHORITY, 0)<0)
      return -1;
  for (cl = options->AlternateHSAuthority; cl; cl = cl->next)
    if (parse_dir_server_line(cl->value, NO_AUTHORITY, 0)<0)
      return -1;
  return 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. */
    if (set_max_file_descriptors((unsigned)options->ConnLimit,
                                 &options->_ConnLimit) < 0) {
      *msg = tor_strdup("Problem with ConnLimit value. See logs for details.");
      goto rollback;
    }