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
#include "../common/aes.h"

/** 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},
  { "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 }
/** 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"),
  VAR("AccountingMax",       MEMUNIT,  AccountingMax,        "0 bytes"),
  VAR("AccountingStart",     STRING,   AccountingStart,      NULL),
  VAR("Address",             STRING,   Address,              NULL),
  VAR("AllowInvalidNodes",   CSV,      AllowInvalidNodes,
                                                        "middle,rendezvous"),
  VAR("AllowNonRFC953Hostnames", BOOL, AllowNonRFC953Hostnames, "0"),
  VAR("AssumeReachable",     BOOL,     AssumeReachable,      "0"),
  VAR("AuthDirBadExit",      LINELIST, AuthDirBadExit,       NULL),
  VAR("AuthDirInvalid",      LINELIST, AuthDirInvalid,       NULL),
  VAR("AuthDirReject",       LINELIST, AuthDirReject,        NULL),
  VAR("AuthDirRejectUnlisted",BOOL,    AuthDirRejectUnlisted,"0"),
  VAR("AuthDirListBadExits", BOOL,     AuthDirListBadExits,  "0"),
  VAR("AuthoritativeDirectory",BOOL,   AuthoritativeDir,     "0"),
  VAR("AvoidDiskWrites",     BOOL,     AvoidDiskWrites,      "0"),
  VAR("BandwidthBurst",      MEMUNIT,  BandwidthBurst,       "6 MB"),
  VAR("BandwidthRate",       MEMUNIT,  BandwidthRate,        "3 MB"),
  VAR("BridgeAuthoritativeDir", BOOL,  BridgeAuthoritativeDir, "0"),
  VAR("Bridge",              LINELIST, Bridges,              NULL),
  VAR("CircuitBuildTimeout", INTERVAL, CircuitBuildTimeout,  "1 minute"),
  VAR("CircuitIdleTimeout",  INTERVAL, CircuitIdleTimeout,   "1 hour"),
  VAR("ClientOnly",          BOOL,     ClientOnly,           "0"),
  VAR("ConnLimit",           UINT,     ConnLimit,            "1000"),
  VAR("ContactInfo",         STRING,   ContactInfo,          NULL),
  VAR("ControlListenAddress",LINELIST, ControlListenAddress, NULL),
  VAR("ControlPort",         UINT,     ControlPort,          "0"),
  VAR("CookieAuthentication",BOOL,     CookieAuthentication, "0"),
  VAR("DataDirectory",       STRING,   DataDirectory,        NULL),
  OBSOLETE("DebugLogFile"),
  VAR("DirAllowPrivateAddresses",BOOL, DirAllowPrivateAddresses, NULL),
  VAR("DirListenAddress",    LINELIST, DirListenAddress,     NULL),
  OBSOLETE("DirFetchPeriod"),
  VAR("DirPolicy",           LINELIST, DirPolicy,            NULL),
  VAR("DirPort",             UINT,     DirPort,              "0"),
  OBSOLETE("DirPostPeriod"),
  VAR("DirServer",           LINELIST, DirServers,           NULL),
  VAR("DownloadExtraInfo",   BOOL,     DownloadExtraInfo,    "0"),
  VAR("EnforceDistinctSubnets", BOOL,  EnforceDistinctSubnets,"1"),
  VAR("EntryNodes",          STRING,   EntryNodes,           NULL),
  VAR("ExcludeNodes",        STRING,   ExcludeNodes,         NULL),
  VAR("ExitNodes",           STRING,   ExitNodes,            NULL),
  VAR("ExitPolicy",          LINELIST, ExitPolicy,           NULL),
  VAR("ExitPolicyRejectPrivate", BOOL, ExitPolicyRejectPrivate, "1"),
  VAR("FascistFirewall",     BOOL,     FascistFirewall,      "0"),
  VAR("FirewallPorts",       CSV,      FirewallPorts,        ""),
  VAR("FastFirstHopPK",      BOOL,     FastFirstHopPK,       "1"),
  VAR("FetchServerDescriptors",BOOL,   FetchServerDescriptors,"1"),
  VAR("FetchHidServDescriptors",BOOL,  FetchHidServDescriptors, "1"),
  VAR("FetchUselessDescriptors",BOOL,  FetchUselessDescriptors, "0"),
  VAR("Group",               STRING,   Group,                NULL),
  VAR("HardwareAccel",       BOOL,     HardwareAccel,        "0"),
  VAR("HashedControlPassword",STRING,  HashedControlPassword, 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),
  VAR("HSAuthoritativeDir",  BOOL,     HSAuthoritativeDir,   "0"),
  VAR("HSAuthorityRecordStats",BOOL,   HSAuthorityRecordStats,"0"),
  VAR("HttpProxy",           STRING,   HttpProxy,            NULL),
  VAR("HttpProxyAuthenticator",STRING, HttpProxyAuthenticator,NULL),
  VAR("HttpsProxy",          STRING,   HttpsProxy,           NULL),
  VAR("HttpsProxyAuthenticator",STRING,HttpsProxyAuthenticator,NULL),
  OBSOLETE("IgnoreVersion"),
  VAR("KeepalivePeriod",     INTERVAL, KeepalivePeriod,      "5 minutes"),
  VAR("Log",                 LINELIST, Logs,                 NULL),
  OBSOLETE("LinkPadding"),
  OBSOLETE("LogLevel"),
  OBSOLETE("LogFile"),
  VAR("LongLivedPorts",      CSV,      LongLivedPorts,
                         "21,22,706,1863,5050,5190,5222,5223,6667,6697,8300"),
  VAR("MapAddress",          LINELIST, AddressMap,           NULL),
  VAR("MaxAdvertisedBandwidth",MEMUNIT,MaxAdvertisedBandwidth,"1 GB"),
  VAR("MaxCircuitDirtiness", INTERVAL, MaxCircuitDirtiness,  "10 minutes"),
  VAR("MaxOnionsPending",    UINT,     MaxOnionsPending,     "100"),
  OBSOLETE("MonthlyAccountingStart"),
  VAR("MyFamily",            STRING,   MyFamily,             NULL),
  VAR("NewCircuitPeriod",    INTERVAL, NewCircuitPeriod,     "30 seconds"),
  VAR("NamingAuthoritativeDirectory",BOOL, NamingAuthoritativeDir, "0"),
  VAR("NatdListenAddress",   LINELIST, NatdListenAddress,    NULL),
  VAR("NatdPort",            UINT,     NatdPort,             "0"),
  VAR("Nickname",            STRING,   Nickname,             NULL),
  VAR("NoPublish",           BOOL,     NoPublish,            "0"),
  VAR("NodeFamily",          LINELIST, NodeFamilies,         NULL),
  VAR("NumCpus",             UINT,     NumCpus,              "1"),
  VAR("NumEntryGuards",      UINT,     NumEntryGuards,       "3"),
  VAR("ORListenAddress",     LINELIST, ORListenAddress,      NULL),
  VAR("ORPort",              UINT,     ORPort,               "0"),
  VAR("OutboundBindAddress", STRING,   OutboundBindAddress,  NULL),
  OBSOLETE("PathlenCoinWeight"),
  VAR("PidFile",             STRING,   PidFile,              NULL),
  VAR("PreferTunneledDirConns", BOOL,  PreferTunneledDirConns, "0"),
  VAR("ProtocolWarnings",    BOOL,     ProtocolWarnings,     "0"),
  VAR("PublishServerDescriptor", CSV,  PublishServerDescriptor,"v1,v2"),
  VAR("PublishHidServDescriptors",BOOL,PublishHidServDescriptors, "1"),
  VAR("ReachableAddresses",  LINELIST, ReachableAddresses,   NULL),
  VAR("ReachableDirAddresses",LINELIST,ReachableDirAddresses,NULL),
  VAR("ReachableORAddresses",LINELIST, ReachableORAddresses, NULL),
  VAR("RecommendedVersions", LINELIST, RecommendedVersions,  NULL),
  VAR("RecommendedClientVersions", LINELIST, RecommendedClientVersions,  NULL),
  VAR("RecommendedServerVersions", LINELIST, RecommendedServerVersions,  NULL),
  VAR("RedirectExit",        LINELIST, RedirectExit,         NULL),
  VAR("RelayBandwidthBurst", MEMUNIT,  RelayBandwidthBurst,  "0"),
  VAR("RelayBandwidthRate",  MEMUNIT,  RelayBandwidthRate,   "0"),
  VAR("RendExcludeNodes",    STRING,   RendExcludeNodes,     NULL),
  VAR("RendNodes",           STRING,   RendNodes,            NULL),
  VAR("RendPostPeriod",      INTERVAL, RendPostPeriod,       "1 hour"),
  VAR("RephistTrackTime",    INTERVAL, RephistTrackTime,     "24 hours"),
  OBSOLETE("RouterFile"),
  VAR("RunAsDaemon",         BOOL,     RunAsDaemon,          "0"),
  VAR("RunTesting",          BOOL,     RunTesting,           "0"),
  VAR("SafeLogging",         BOOL,     SafeLogging,          "1"),
  VAR("SafeSocks",           BOOL,     SafeSocks,            "0"),
  VAR("ServerDNSAllowNonRFC953Hostnames",
                             BOOL,     ServerDNSAllowNonRFC953Hostnames, "0"),
  VAR("ServerDNSDetectHijacking",BOOL,   ServerDNSDetectHijacking,"1"),
  VAR("ServerDNSResolvConfFile", STRING, ServerDNSResolvConfFile, NULL),
  VAR("ServerDNSSearchDomains",  BOOL,   ServerDNSSearchDomains,  "0"),
  VAR("ServerDNSTestAddresses",  CSV,    ServerDNSTestAddresses,
      "www.google.com,www.mit.edu,www.yahoo.com,www.slashdot.org"),
  VAR("ShutdownWaitLength",  INTERVAL, ShutdownWaitLength,   "30 seconds"),
  VAR("SocksListenAddress",  LINELIST, SocksListenAddress,   NULL),
  VAR("SocksPolicy",         LINELIST, SocksPolicy,          NULL),
  VAR("SocksPort",           UINT,     SocksPort,            "9050"),
  VAR("SocksTimeout",        INTERVAL, SocksTimeout,         "2 minutes"),
  OBSOLETE("StatusFetchPeriod"),
  VAR("StrictEntryNodes",    BOOL,     StrictEntryNodes,     "0"),
  VAR("StrictExitNodes",     BOOL,     StrictExitNodes,      "0"),
  OBSOLETE("SysLog"),
  VAR("TestSocks",           BOOL,     TestSocks,            "0"),
  VAR("TestVia",             STRING,   TestVia,              NULL),
  VAR("TrackHostExits",      CSV,      TrackHostExits,       NULL),
  VAR("TrackHostExitsExpire",INTERVAL, TrackHostExitsExpire, "30 minutes"),
  OBSOLETE("TrafficShaping"),
  VAR("TransListenAddress",  LINELIST, TransListenAddress,   NULL),
  VAR("TransPort",           UINT,     TransPort,            "0"),
  VAR("TunnelDirConns",      BOOL,     TunnelDirConns,       "0"),
  VAR("UseBridges",          BOOL,     UseBridges,           "0"),
  VAR("UseEntryGuards",      BOOL,     UseEntryGuards,       "1"),
  VAR("User",                STRING,   User,                 NULL),
  VAR("V1AuthoritativeDirectory",BOOL, V1AuthoritativeDir,   "0"),
  VAR("V2AuthoritativeDirectory",BOOL, V2AuthoritativeDir,   "0"),
  VAR("V3AuthoritativeDirectory",BOOL, V3AuthoritativeDir,   "0"),
  VAR("VersioningAuthoritativeDirectory",BOOL,VersioningAuthoritativeDir, "0"),
  VAR("VirtualAddrNetwork",  STRING,   VirtualAddrNetwork,   "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[] = {
  VAR("AccountingBytesReadInInterval", MEMUNIT,
      AccountingBytesReadInInterval, NULL),
  VAR("AccountingBytesWrittenInInterval", MEMUNIT,
      AccountingBytesWrittenInInterval, NULL),
  VAR("AccountingExpectedUsage", MEMUNIT,     AccountingExpectedUsage, NULL),
  VAR("AccountingIntervalStart", ISOTIME,     AccountingIntervalStart, NULL),
  VAR("AccountingSecondsActive", INTERVAL,    AccountingSecondsActive, NULL),
  VAR("EntryGuard",              LINELIST_S,  EntryGuards,             NULL),
  VAR("EntryGuardDownSince",     LINELIST_S,  EntryGuards,             NULL),
  VAR("EntryGuardUnlistedSince", LINELIST_S,  EntryGuards,             NULL),
  VAR("EntryGuards",             LINELIST_V,  EntryGuards,             NULL),

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

  VAR("TorVersion",              STRING,      TorVersion,             NULL),

  VAR("LastRotatedOnionKey",     ISOTIME,     LastRotatedOnionKey,    NULL),
  VAR("LastWritten",             ISOTIME,     LastWritten,            NULL),

  { NULL, CONFIG_TYPE_OBSOLETE, 0, NULL }
};

#undef VAR
#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." },
  /*  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 conncetions." },
  /* 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." },
  { "PublishServerDescriptors", "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) do {                                            \
    tor_assert(fmt && cfg);                                             \
    tor_assert((fmt)->magic ==                                          \
               *(uint32_t*)STRUCT_VAR_P(cfg,fmt->magic_offset));        \
  } while (0)

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 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_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 main.c */

/** Return the current Tor version, possibly */
const char *
get_version(void)
{
  static char *version = NULL;
  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);
}

/** If options->SafeLogging is on, return a not very useful string,
 * else return address.
 */
const char *
safe_str(const char *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[] = {
    /* eventually we should mark moria1 as "v1only" */
    "moria1 v1 orport=9001 18.244.0.188:9031 "
      "FFCB 46DB 1339 DA84 674C 70D7 CB58 6434 C437 0441",
    "moria2 v1 orport=443 18.244.0.114:80 "
      "719B E45D E224 B607 C537 07D0 E214 3E2D 423E 74CF",
    "tor26 v1 orport=443 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",
    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;

  if (running_tor && options->RunAsDaemon) {
    /* No need to roll back, since you can't change the value. */
    start_daemon();
  }

  /* 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;
    }
  }

  /* Set up libevent. */
  if (running_tor && !libevent_initialized) {
    init_libevent();
    libevent_initialized = 1;
  }

  /* 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 (options->command != CMD_RUN_TOR)
    goto commit;

  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;

  if (retry_all_listeners(0, replaced_listeners, new_listeners) < 0) {
    *msg = tor_strdup("Failed to bind one of the listener ports.");
    goto rollback;
  }

  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);