gnupg/agent/gpg-agent.c

/* gpg-agent.c  -  The GnuPG Agent
 * Copyright (C) 2000-2007, 2009-2010 Free Software Foundation, Inc.
 * Copyright (C) 2000-2016 Werner Koch
 *
 * This file is part of GnuPG.
 *
 * GnuPG is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 3 of the License, or
 * (at your option) any later version.
 *
 * GnuPG is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, see <http://www.gnu.org/licenses/>.
 */

#include <config.h>

#include <stdio.h>
#include <stdlib.h>
#include <stddef.h>
#include <stdarg.h>
#include <string.h>
#include <errno.h>
#include <assert.h>
#include <time.h>
#include <fcntl.h>
#include <sys/stat.h>
#ifdef HAVE_W32_SYSTEM
# ifndef WINVER
#  define WINVER 0x0500  /* Same as in common/sysutils.c */
# endif
# ifdef HAVE_WINSOCK2_H
#  include <winsock2.h>
# endif
# include <aclapi.h>
# include <sddl.h>
#else /*!HAVE_W32_SYSTEM*/
# include <sys/socket.h>
# include <sys/un.h>
#endif /*!HAVE_W32_SYSTEM*/
#include <unistd.h>
#ifdef HAVE_SIGNAL_H
# include <signal.h>
#endif
#ifdef HAVE_INOTIFY_INIT
# include <sys/inotify.h>
#endif /*HAVE_INOTIFY_INIT*/
#include <npth.h>

#define GNUPG_COMMON_NEED_AFLOCAL
#include "agent.h"
#include <assuan.h> /* Malloc hooks  and socket wrappers. */

#include "i18n.h"
#include "sysutils.h"
#include "gc-opt-flags.h"
#include "exechelp.h"
#include "asshelp.h"
#include "../common/init.h"


enum cmd_and_opt_values
{ aNull = 0,
  oCsh		  = 'c',
  oQuiet	  = 'q',
  oSh		  = 's',
  oVerbose	  = 'v',

  oNoVerbose = 500,
  aGPGConfList,
  aGPGConfTest,
  aUseStandardSocketP,
  oOptions,
  oDebug,
  oDebugAll,
  oDebugLevel,
  oDebugWait,
  oDebugQuickRandom,
  oDebugPinentry,
  oNoGreeting,
  oNoOptions,
  oHomedir,
  oNoDetach,
  oNoGrab,
  oLogFile,
  oServer,
  oDaemon,
  oBatch,

  oPinentryProgram,
  oPinentryTouchFile,
  oPinentryInvisibleChar,
  oPinentryTimeout,
  oDisplay,
  oTTYname,
  oTTYtype,
  oLCctype,
  oLCmessages,
  oXauthority,
  oScdaemonProgram,
  oDefCacheTTL,
  oDefCacheTTLSSH,
  oMaxCacheTTL,
  oMaxCacheTTLSSH,
  oEnforcePassphraseConstraints,
  oMinPassphraseLen,
  oMinPassphraseNonalpha,
  oCheckPassphrasePattern,
  oMaxPassphraseDays,
  oEnablePassphraseHistory,
  oUseStandardSocket,
  oNoUseStandardSocket,
  oExtraSocket,
  oBrowserSocket,
  oFakedSystemTime,

  oIgnoreCacheForSigning,
  oAllowMarkTrusted,
  oNoAllowMarkTrusted,
  oAllowPresetPassphrase,
  oAllowLoopbackPinentry,
  oNoAllowLoopbackPinentry,
  oNoAllowExternalCache,
  oAllowEmacsPinentry,
  oKeepTTY,
  oKeepDISPLAY,
  oSSHSupport,
  oPuttySupport,
  oDisableScdaemon,
  oDisableCheckOwnSocket,
  oWriteEnvFile
};


#ifndef ENAMETOOLONG
# define ENAMETOOLONG EINVAL
#endif


static ARGPARSE_OPTS opts[] = {

  ARGPARSE_c (aGPGConfList, "gpgconf-list", "@"),
  ARGPARSE_c (aGPGConfTest, "gpgconf-test", "@"),
  ARGPARSE_c (aUseStandardSocketP, "use-standard-socket-p", "@"),

  ARGPARSE_group (301, N_("@Options:\n ")),

  ARGPARSE_s_n (oDaemon,  "daemon", N_("run in daemon mode (background)")),
  ARGPARSE_s_n (oServer,  "server", N_("run in server mode (foreground)")),
  ARGPARSE_s_n (oVerbose, "verbose", N_("verbose")),
  ARGPARSE_s_n (oQuiet,	  "quiet",     N_("be somewhat more quiet")),
  ARGPARSE_s_n (oSh,	  "sh",        N_("sh-style command output")),
  ARGPARSE_s_n (oCsh,	  "csh",       N_("csh-style command output")),
  ARGPARSE_s_s (oOptions, "options", N_("|FILE|read options from FILE")),

  ARGPARSE_s_s (oDebug,	     "debug",       "@"),
  ARGPARSE_s_n (oDebugAll,   "debug-all",   "@"),
  ARGPARSE_s_s (oDebugLevel, "debug-level", "@"),
  ARGPARSE_s_i (oDebugWait,"  debug-wait",  "@"),
  ARGPARSE_s_n (oDebugQuickRandom, "debug-quick-random", "@"),
  ARGPARSE_s_n (oDebugPinentry, "debug-pinentry", "@"),

  ARGPARSE_s_n (oNoDetach,  "no-detach", N_("do not detach from the console")),
  ARGPARSE_s_n (oNoGrab,    "no-grab",   N_("do not grab keyboard and mouse")),
  ARGPARSE_s_s (oLogFile,   "log-file",  N_("use a log file for the server")),
  ARGPARSE_s_s (oPinentryProgram, "pinentry-program",
                /* */             N_("|PGM|use PGM as the PIN-Entry program")),
  ARGPARSE_s_s (oPinentryTouchFile, "pinentry-touch-file", "@"),
  ARGPARSE_s_s (oPinentryInvisibleChar, "pinentry-invisible-char", "@"),
  ARGPARSE_s_u (oPinentryTimeout, "pinentry-timeout", "@"),
  ARGPARSE_s_s (oScdaemonProgram, "scdaemon-program",
                /* */             N_("|PGM|use PGM as the SCdaemon program") ),
  ARGPARSE_s_n (oDisableScdaemon, "disable-scdaemon",
                /* */             N_("do not use the SCdaemon") ),
  ARGPARSE_s_n (oDisableCheckOwnSocket, "disable-check-own-socket", "@"),

  ARGPARSE_s_s (oExtraSocket, "extra-socket",
                /* */       N_("|NAME|accept some commands via NAME")),

  ARGPARSE_s_s (oBrowserSocket, "browser-socket", "@"),

  ARGPARSE_s_s (oFakedSystemTime, "faked-system-time", "@"),

  ARGPARSE_s_n (oBatch,      "batch",        "@"),
  ARGPARSE_s_s (oHomedir,    "homedir",      "@"),

  ARGPARSE_s_s (oDisplay,    "display",     "@"),
  ARGPARSE_s_s (oTTYname,    "ttyname",     "@"),
  ARGPARSE_s_s (oTTYtype,    "ttytype",     "@"),
  ARGPARSE_s_s (oLCctype,    "lc-ctype",    "@"),
  ARGPARSE_s_s (oLCmessages, "lc-messages", "@"),
  ARGPARSE_s_s (oXauthority, "xauthority",  "@"),
  ARGPARSE_s_n (oKeepTTY,    "keep-tty",
                /* */        N_("ignore requests to change the TTY")),
  ARGPARSE_s_n (oKeepDISPLAY, "keep-display",
                /* */        N_("ignore requests to change the X display")),

  ARGPARSE_s_u (oDefCacheTTL,    "default-cache-ttl",
                                 N_("|N|expire cached PINs after N seconds")),
  ARGPARSE_s_u (oDefCacheTTLSSH, "default-cache-ttl-ssh", "@" ),
  ARGPARSE_s_u (oMaxCacheTTL,    "max-cache-ttl",         "@" ),
  ARGPARSE_s_u (oMaxCacheTTLSSH, "max-cache-ttl-ssh",     "@" ),

  ARGPARSE_s_n (oEnforcePassphraseConstraints, "enforce-passphrase-constraints",
                /* */                          "@"),
  ARGPARSE_s_u (oMinPassphraseLen,        "min-passphrase-len", "@"),
  ARGPARSE_s_u (oMinPassphraseNonalpha,   "min-passphrase-nonalpha", "@"),
  ARGPARSE_s_s (oCheckPassphrasePattern,  "check-passphrase-pattern", "@"),
  ARGPARSE_s_u (oMaxPassphraseDays,       "max-passphrase-days", "@"),
  ARGPARSE_s_n (oEnablePassphraseHistory, "enable-passphrase-history", "@"),

  ARGPARSE_s_n (oIgnoreCacheForSigning, "ignore-cache-for-signing",
                /* */    N_("do not use the PIN cache when signing")),
  ARGPARSE_s_n (oNoAllowExternalCache,  "no-allow-external-cache",
                /* */    N_("disallow the use of an external password cache")),
  ARGPARSE_s_n (oNoAllowMarkTrusted, "no-allow-mark-trusted",
                /* */    N_("disallow clients to mark keys as \"trusted\"")),
  ARGPARSE_s_n (oAllowMarkTrusted,   "allow-mark-trusted", "@"),
  ARGPARSE_s_n (oAllowPresetPassphrase, "allow-preset-passphrase",
                /* */                    N_("allow presetting passphrase")),
  ARGPARSE_s_n (oNoAllowLoopbackPinentry, "no-allow-loopback-pinentry",
                                N_("disallow caller to override the pinentry")),
  ARGPARSE_s_n (oAllowLoopbackPinentry, "allow-loopback-pinentry", "@"),
  ARGPARSE_s_n (oAllowEmacsPinentry,  "allow-emacs-pinentry",
                /* */    N_("allow passphrase to be prompted through Emacs")),

  ARGPARSE_s_n (oSSHSupport,   "enable-ssh-support", N_("enable ssh support")),
  ARGPARSE_s_n (oPuttySupport, "enable-putty-support",
#ifdef HAVE_W32_SYSTEM
                /* */           N_("enable putty support")
#else
                /* */           "@"
#endif
                ),

  /* Dummy options for backward compatibility.  */
  ARGPARSE_o_s (oWriteEnvFile, "write-env-file", "@"),
  ARGPARSE_s_n (oUseStandardSocket, "use-standard-socket", "@"),
  ARGPARSE_s_n (oNoUseStandardSocket, "no-use-standard-socket", "@"),

  {0} /* End of list */
};


/* The list of supported debug flags.  */
static struct debug_flags_s debug_flags [] =
  {
    { DBG_COMMAND_VALUE, "command"  },
    { DBG_MPI_VALUE    , "mpi"     },
    { DBG_CRYPTO_VALUE , "crypto"  },
    { DBG_MEMORY_VALUE , "memory"  },
    { DBG_CACHE_VALUE  , "cache"   },
    { DBG_MEMSTAT_VALUE, "memstat" },
    { DBG_HASHING_VALUE, "hashing" },
    { DBG_IPC_VALUE    , "ipc"     },
    { 77, NULL } /* 77 := Do not exit on "help" or "?".  */
  };



#define DEFAULT_CACHE_TTL     (10*60)  /* 10 minutes */
#define DEFAULT_CACHE_TTL_SSH (30*60)  /* 30 minutes */
#define MAX_CACHE_TTL         (120*60) /* 2 hours */
#define MAX_CACHE_TTL_SSH     (120*60) /* 2 hours */
#define MIN_PASSPHRASE_LEN    (8)
#define MIN_PASSPHRASE_NONALPHA (1)
#define MAX_PASSPHRASE_DAYS   (0)

/* The timer tick used for housekeeping stuff.  For Windows we use a
   longer period as the SetWaitableTimer seems to signal earlier than
   the 2 seconds.  CHECK_OWN_SOCKET_INTERVAL defines how often we
   check our own socket in standard socket mode.  If that value is 0
   we don't check at all.   All values are in seconds. */
#if defined(HAVE_W32CE_SYSTEM)
# define TIMERTICK_INTERVAL         (60)
# define CHECK_OWN_SOCKET_INTERVAL   (0)  /* Never */
#elif defined(HAVE_W32_SYSTEM)
# define TIMERTICK_INTERVAL          (4)
# define CHECK_OWN_SOCKET_INTERVAL  (60)
#else
# define TIMERTICK_INTERVAL          (2)
# define CHECK_OWN_SOCKET_INTERVAL  (60)
#endif


/* Flag indicating that the ssh-agent subsystem has been enabled.  */
static int ssh_support;

#ifdef HAVE_W32_SYSTEM
/* Flag indicating that support for Putty has been enabled.  */
static int putty_support;
/* A magic value used with WM_COPYDATA.  */
#define PUTTY_IPC_MAGIC 0x804e50ba
/* To avoid surprises we limit the size of the mapped IPC file to this
   value.  Putty currently (0.62) uses 8k, thus 16k should be enough
   for the foreseeable future.  */
#define PUTTY_IPC_MAXLEN 16384
#endif /*HAVE_W32_SYSTEM*/

/* The list of open file descriptors at startup.  Note that this list
   has been allocated using the standard malloc.  */
static int *startup_fd_list;

/* The signal mask at startup and a flag telling whether it is valid.  */
#ifdef HAVE_SIGPROCMASK
static sigset_t startup_signal_mask;
static int startup_signal_mask_valid;
#endif

/* Flag to indicate that a shutdown was requested.  */
static int shutdown_pending;

/* Counter for the currently running own socket checks.  */
static int check_own_socket_running;

/* Flags to indicate that check_own_socket shall not be called.  */
static int disable_check_own_socket;

/* It is possible that we are currently running under setuid permissions */
static int maybe_setuid = 1;

/* Name of the communication socket used for native gpg-agent
   requests. The second variable is either NULL or a malloced string
   with the real socket name in case it has been redirected.  */
static char *socket_name;
static char *redir_socket_name;

/* Name of the optional extra socket used for native gpg-agent requests.  */
static char *socket_name_extra;
static char *redir_socket_name_extra;

/* Name of the optional browser socket used for native gpg-agent requests.  */
static char *socket_name_browser;
static char *redir_socket_name_browser;

/* Name of the communication socket used for ssh-agent-emulation.  */
static char *socket_name_ssh;
static char *redir_socket_name_ssh;

/* We need to keep track of the server's nonces (these are dummies for
   POSIX systems). */
static assuan_sock_nonce_t socket_nonce;
static assuan_sock_nonce_t socket_nonce_extra;
static assuan_sock_nonce_t socket_nonce_browser;
static assuan_sock_nonce_t socket_nonce_ssh;


/* Default values for options passed to the pinentry. */
static char *default_display;
static char *default_ttyname;
static char *default_ttytype;
static char *default_lc_ctype;
static char *default_lc_messages;
static char *default_xauthority;

/* Name of a config file, which will be reread on a HUP if it is not NULL. */
static char *config_filename;

/* Helper to implement --debug-level */
static const char *debug_level;

/* Keep track of the current log file so that we can avoid updating
   the log file after a SIGHUP if it didn't changed. Malloced. */
static char *current_logfile;

/* The handle_tick() function may test whether a parent is still
   running.  We record the PID of the parent here or -1 if it should be
   watched. */
static pid_t parent_pid = (pid_t)(-1);

/* Number of active connections.  */
static int active_connections;

/* This object is used to dispatch progress messages from Libgcrypt to
 * the right thread.  Given that we won't have at max a few dozen
 * connections at the same time using a linked list is the easiest way
 * to handle this. */
struct progress_dispatch_s
{
  struct progress_dispatch_s *next;
  /* The control object of the connection.  If this is NULL no
   * connection is associated with this item and it is free for reuse
   * by new connections.  */
  ctrl_t ctrl;

  /* The thread id of (npth_self) of the connection.  */
  npth_t tid;

  /* The callback set by the connection.  This is similar to the
   * Libgcrypt callback but with the control object passed as the
   * first argument.  */
  void (*cb)(ctrl_t ctrl,
             const char *what, int printchar,
             int current, int total);
};
struct progress_dispatch_s *progress_dispatch_list;




/*
   Local prototypes.
 */

static char *create_socket_name (char *standard_name, int with_homedir);
static gnupg_fd_t create_server_socket (char *name, int primary, int cygwin,
                                        char **r_redir_name,
                                        assuan_sock_nonce_t *nonce);
static void create_directories (void);

static void agent_libgcrypt_progress_cb (void *data, const char *what,
                                         int printchar,
                                         int current, int total);
static void agent_init_default_ctrl (ctrl_t ctrl);
static void agent_deinit_default_ctrl (ctrl_t ctrl);

static void handle_connections (gnupg_fd_t listen_fd,
                                gnupg_fd_t listen_fd_extra,
                                gnupg_fd_t listen_fd_browser,
                                gnupg_fd_t listen_fd_ssh);
static void check_own_socket (void);
static int check_for_running_agent (int silent);

/* Pth wrapper function definitions. */
ASSUAN_SYSTEM_NPTH_IMPL;


/*
   Functions.
 */

/* Allocate a string describing a library version by calling a GETFNC.
   This function is expected to be called only once.  GETFNC is
   expected to have a semantic like gcry_check_version ().  */
static char *
make_libversion (const char *libname, const char *(*getfnc)(const char*))
{
  const char *s;
  char *result;

  if (maybe_setuid)
    {
      gcry_control (GCRYCTL_INIT_SECMEM, 0, 0);  /* Drop setuid. */
      maybe_setuid = 0;
    }
  s = getfnc (NULL);
  result = xmalloc (strlen (libname) + 1 + strlen (s) + 1);
  strcpy (stpcpy (stpcpy (result, libname), " "), s);
  return result;
}

/* Return strings describing this program.  The case values are
   described in common/argparse.c:strusage.  The values here override
   the default values given by strusage.  */
static const char *
my_strusage (int level)
{
  static char *ver_gcry;
  const char *p;

  switch (level)
    {
    case 11: p = "@GPG_AGENT@ (@GNUPG@)";
      break;
    case 13: p = VERSION; break;
    case 17: p = PRINTABLE_OS_NAME; break;
      /* TRANSLATORS: @EMAIL@ will get replaced by the actual bug
         reporting address.  This is so that we can change the
         reporting address without breaking the translations.  */
    case 19: p = _("Please report bugs to <@EMAIL@>.\n"); break;

    case 20:
      if (!ver_gcry)
        ver_gcry = make_libversion ("libgcrypt", gcry_check_version);
      p = ver_gcry;
      break;

    case 1:
    case 40: p =  _("Usage: @GPG_AGENT@ [options] (-h for help)");
      break;
    case 41: p =  _("Syntax: @GPG_AGENT@ [options] [command [args]]\n"
                    "Secret key management for @GNUPG@\n");
    break;

    default: p = NULL;
    }
  return p;
}



/* Setup the debugging.  With the global variable DEBUG_LEVEL set to NULL
   only the active debug flags are propagated to the subsystems.  With
   DEBUG_LEVEL set, a specific set of debug flags is set; thus overriding
   all flags already set. Note that we don't fail here, because it is
   important to keep gpg-agent running even after re-reading the
   options due to a SIGHUP. */
static void
set_debug (void)
{
  int numok = (debug_level && digitp (debug_level));
  int numlvl = numok? atoi (debug_level) : 0;

  if (!debug_level)
    ;
  else if (!strcmp (debug_level, "none") || (numok && numlvl < 1))
    opt.debug = 0;
  else if (!strcmp (debug_level, "basic") || (numok && numlvl <= 2))
    opt.debug = DBG_IPC_VALUE;
  else if (!strcmp (debug_level, "advanced") || (numok && numlvl <= 5))
    opt.debug = DBG_IPC_VALUE|DBG_COMMAND_VALUE;
  else if (!strcmp (debug_level, "expert") || (numok && numlvl <= 8))
    opt.debug = (DBG_IPC_VALUE|DBG_COMMAND_VALUE
                 |DBG_CACHE_VALUE);
  else if (!strcmp (debug_level, "guru") || numok)
    {
      opt.debug = ~0;
      /* Unless the "guru" string has been used we don't want to allow
         hashing debugging.  The rationale is that people tend to
         select the highest debug value and would then clutter their
         disk with debug files which may reveal confidential data.  */
      if (numok)
        opt.debug &= ~(DBG_HASHING_VALUE);
    }
  else
    {
      log_error (_("invalid debug-level '%s' given\n"), debug_level);
      opt.debug = 0; /* Reset debugging, so that prior debug
                        statements won't have an undesired effect. */
    }

  if (opt.debug && !opt.verbose)
    opt.verbose = 1;
  if (opt.debug && opt.quiet)
    opt.quiet = 0;

  if (opt.debug & DBG_MPI_VALUE)
    gcry_control (GCRYCTL_SET_DEBUG_FLAGS, 2);
  if (opt.debug & DBG_CRYPTO_VALUE )
    gcry_control (GCRYCTL_SET_DEBUG_FLAGS, 1);
  gcry_control (GCRYCTL_SET_VERBOSITY, (int)opt.verbose);

  if (opt.debug)
    parse_debug_flag (NULL, &opt.debug, debug_flags);
}


/* Helper for cleanup to remove one socket with NAME.  REDIR_NAME is
   the corresponding real name if the socket has been redirected.  */
static void
remove_socket (char *name, char *redir_name)
{
  if (name && *name)
    {
      if (redir_name)
        name = redir_name;

      gnupg_remove (name);
      *name = 0;
    }
}


/* Cleanup code for this program.  This is either called has an atexit
   handler or directly.  */
static void
cleanup (void)
{
  static int done;

  if (done)
    return;
  done = 1;
  deinitialize_module_cache ();
  remove_socket (socket_name, redir_socket_name);
  if (opt.extra_socket > 1)
    remove_socket (socket_name_extra, redir_socket_name_extra);
  if (opt.browser_socket > 1)
    remove_socket (socket_name_browser, redir_socket_name_browser);
  remove_socket (socket_name_ssh, redir_socket_name_ssh);
}



/* Handle options which are allowed to be reset after program start.
   Return true when the current option in PARGS could be handled and
   false if not.  As a special feature, passing a value of NULL for
   PARGS, resets the options to the default.  REREAD should be set
   true if it is not the initial option parsing. */
static int
parse_rereadable_options (ARGPARSE_ARGS *pargs, int reread)
{
  if (!pargs)
    { /* reset mode */
      opt.quiet = 0;
      opt.verbose = 0;
      opt.debug = 0;
      opt.no_grab = 0;
      opt.debug_pinentry = 0;
      opt.pinentry_program = NULL;
      opt.pinentry_touch_file = NULL;
      xfree (opt.pinentry_invisible_char);
      opt.pinentry_invisible_char = NULL;
      opt.pinentry_timeout = 0;
      opt.scdaemon_program = NULL;
      opt.def_cache_ttl = DEFAULT_CACHE_TTL;
      opt.def_cache_ttl_ssh = DEFAULT_CACHE_TTL_SSH;
      opt.max_cache_ttl = MAX_CACHE_TTL;
      opt.max_cache_ttl_ssh = MAX_CACHE_TTL_SSH;
      opt.enforce_passphrase_constraints = 0;
      opt.min_passphrase_len = MIN_PASSPHRASE_LEN;
      opt.min_passphrase_nonalpha = MIN_PASSPHRASE_NONALPHA;
      opt.check_passphrase_pattern = NULL;
      opt.max_passphrase_days = MAX_PASSPHRASE_DAYS;
      opt.enable_passhrase_history = 0;
      opt.ignore_cache_for_signing = 0;
      opt.allow_mark_trusted = 1;
      opt.allow_external_cache = 1;
      opt.allow_loopback_pinentry = 1;
      opt.allow_emacs_pinentry = 0;
      opt.disable_scdaemon = 0;
      disable_check_own_socket = 0;
      return 1;
    }

  switch (pargs->r_opt)
    {
    case oQuiet: opt.quiet = 1; break;
    case oVerbose: opt.verbose++; break;

    case oDebug:
      parse_debug_flag (pargs->r.ret_str, &opt.debug, debug_flags);
      break;
    case oDebugAll: opt.debug = ~0; break;
    case oDebugLevel: debug_level = pargs->r.ret_str; break;
    case oDebugPinentry: opt.debug_pinentry = 1; break;

    case oLogFile:
      if (!reread)
        return 0; /* not handeld */
      if (!current_logfile || !pargs->r.ret_str
          || strcmp (current_logfile, pargs->r.ret_str))
        {
          log_set_file (pargs->r.ret_str);
          xfree (current_logfile);
          current_logfile = xtrystrdup (pargs->r.ret_str);
        }
      break;

    case oNoGrab: opt.no_grab = 1; break;

    case oPinentryProgram: opt.pinentry_program = pargs->r.ret_str; break;
    case oPinentryTouchFile: opt.pinentry_touch_file = pargs->r.ret_str; break;
    case oPinentryInvisibleChar:
      xfree (opt.pinentry_invisible_char);
      opt.pinentry_invisible_char = xtrystrdup (pargs->r.ret_str); break;
      break;
    case oPinentryTimeout: opt.pinentry_timeout = pargs->r.ret_ulong; break;
    case oScdaemonProgram: opt.scdaemon_program = pargs->r.ret_str; break;
    case oDisableScdaemon: opt.disable_scdaemon = 1; break;
    case oDisableCheckOwnSocket: disable_check_own_socket = 1; break;

    case oDefCacheTTL: opt.def_cache_ttl = pargs->r.ret_ulong; break;
    case oDefCacheTTLSSH: opt.def_cache_ttl_ssh = pargs->r.ret_ulong; break;
    case oMaxCacheTTL: opt.max_cache_ttl = pargs->r.ret_ulong; break;
    case oMaxCacheTTLSSH: opt.max_cache_ttl_ssh = pargs->r.ret_ulong; break;

    case oEnforcePassphraseConstraints:
      opt.enforce_passphrase_constraints=1;
      break;
    case oMinPassphraseLen: opt.min_passphrase_len = pargs->r.ret_ulong; break;
    case oMinPassphraseNonalpha:
      opt.min_passphrase_nonalpha = pargs->r.ret_ulong;
      break;
    case oCheckPassphrasePattern:
      opt.check_passphrase_pattern = pargs->r.ret_str;
      break;
    case oMaxPassphraseDays:
      opt.max_passphrase_days = pargs->r.ret_ulong;
      break;
    case oEnablePassphraseHistory:
      opt.enable_passhrase_history = 1;
      break;

    case oIgnoreCacheForSigning: opt.ignore_cache_for_signing = 1; break;

    case oAllowMarkTrusted: opt.allow_mark_trusted = 1; break;
    case oNoAllowMarkTrusted: opt.allow_mark_trusted = 0; break;

    case oAllowPresetPassphrase: opt.allow_preset_passphrase = 1; break;

    case oAllowLoopbackPinentry: opt.allow_loopback_pinentry = 1; break;
    case oNoAllowLoopbackPinentry: opt.allow_loopback_pinentry = 0; break;

    case oNoAllowExternalCache: opt.allow_external_cache = 0;
      break;

    case oAllowEmacsPinentry: opt.allow_emacs_pinentry = 1;
      break;

    default:
      return 0; /* not handled */
    }

  return 1; /* handled */
}


/* Fixup some options after all have been processed.  */
static void
finalize_rereadable_options (void)
{
}


static void
thread_init_once (void)
{
  static int npth_initialized = 0;

  if (!npth_initialized)
    {
      npth_initialized++;
      npth_init ();
    }
}

static void
initialize_modules (void)
{
  thread_init_once ();
  assuan_set_system_hooks (ASSUAN_SYSTEM_NPTH);
  initialize_module_cache ();
  initialize_module_call_pinentry ();
  initialize_module_call_scd ();
  initialize_module_trustlist ();
}


/* The main entry point.  */
int
main (int argc, char **argv )
{
  ARGPARSE_ARGS pargs;
  int orig_argc;
  char **orig_argv;
  FILE *configfp = NULL;
  char *configname = NULL;
  const char *shell;
  unsigned configlineno;
  int parse_debug = 0;
  int default_config =1;
  int pipe_server = 0;
  int is_daemon = 0;
  int nodetach = 0;
  int csh_style = 0;
  char *logfile = NULL;
  int debug_wait = 0;
  int gpgconf_list = 0;
  gpg_error_t err;
  struct assuan_malloc_hooks malloc_hooks;

  early_system_init ();

  /* Before we do anything else we save the list of currently open
     file descriptors and the signal mask.  This info is required to
     do the exec call properly. */
  startup_fd_list = get_all_open_fds ();
#ifdef HAVE_SIGPROCMASK
  if (!sigprocmask (SIG_UNBLOCK, NULL, &startup_signal_mask))
    startup_signal_mask_valid = 1;
#endif /*HAVE_SIGPROCMASK*/

  /* Set program name etc.  */
  set_strusage (my_strusage);
  gcry_control (GCRYCTL_SUSPEND_SECMEM_WARN);
  /* Please note that we may running SUID(ROOT), so be very CAREFUL
     when adding any stuff between here and the call to INIT_SECMEM()
     somewhere after the option parsing */
  log_set_prefix (GPG_AGENT_NAME, GPGRT_LOG_WITH_PREFIX|GPGRT_LOG_WITH_PID);

  /* Make sure that our subsystems are ready.  */
  i18n_init ();
  init_common_subsystems (&argc, &argv);

  malloc_hooks.malloc = gcry_malloc;
  malloc_hooks.realloc = gcry_realloc;
  malloc_hooks.free = gcry_free;
  assuan_set_malloc_hooks (&malloc_hooks);
  assuan_set_gpg_err_source (GPG_ERR_SOURCE_DEFAULT);
  assuan_sock_init ();
  setup_libassuan_logging (&opt.debug, NULL);

  setup_libgcrypt_logging ();
  gcry_control (GCRYCTL_USE_SECURE_RNDPOOL);
  gcry_set_progress_handler (agent_libgcrypt_progress_cb, NULL);

  disable_core_dumps ();

  /* Set default options.  */
  parse_rereadable_options (NULL, 0); /* Reset them to default values. */

  shell = getenv ("SHELL");
  if (shell && strlen (shell) >= 3 && !strcmp (shell+strlen (shell)-3, "csh") )
    csh_style = 1;

  /* Record some of the original environment strings. */
  {
    const char *s;
    int idx;
    static const char *names[] =
      { "DISPLAY", "TERM", "XAUTHORITY", "PINENTRY_USER_DATA", NULL };

    err = 0;
    opt.startup_env = session_env_new ();
    if (!opt.startup_env)
      err = gpg_error_from_syserror ();
    for (idx=0; !err && names[idx]; idx++)
      {
        s = getenv (names[idx]);
        if (s)
          err = session_env_setenv (opt.startup_env, names[idx], s);
      }
    if (!err)
      {
        s = gnupg_ttyname (0);
        if (s)
          err = session_env_setenv (opt.startup_env, "GPG_TTY", s);
      }
    if (err)
      log_fatal ("error recording startup environment: %s\n",
                 gpg_strerror (err));

    /* Fixme: Better use the locale function here.  */
    opt.startup_lc_ctype = getenv ("LC_CTYPE");
    if (opt.startup_lc_ctype)
      opt.startup_lc_ctype = xstrdup (opt.startup_lc_ctype);
    opt.startup_lc_messages = getenv ("LC_MESSAGES");
    if (opt.startup_lc_messages)
      opt.startup_lc_messages = xstrdup (opt.startup_lc_messages);
  }

  /* Check whether we have a config file on the commandline */
  orig_argc = argc;
  orig_argv = argv;
  pargs.argc = &argc;
  pargs.argv = &argv;
  pargs.flags= 1|(1<<6);  /* do not remove the args, ignore version */
  while (arg_parse( &pargs, opts))
    {
      if (pargs.r_opt == oDebug || pargs.r_opt == oDebugAll)
        parse_debug++;
      else if (pargs.r_opt == oOptions)
        { /* yes there is one, so we do not try the default one, but
	     read the option file when it is encountered at the
	     commandline */
          default_config = 0;
	}
	else if (pargs.r_opt == oNoOptions)
          default_config = 0; /* --no-options */
	else if (pargs.r_opt == oHomedir)
          gnupg_set_homedir (pargs.r.ret_str);
	else if (pargs.r_opt == oDebugQuickRandom)
          {
            gcry_control (GCRYCTL_ENABLE_QUICK_RANDOM, 0);
          }

    }

  /* Initialize the secure memory. */
  gcry_control (GCRYCTL_INIT_SECMEM, 32768, 0);
  maybe_setuid = 0;

  /*
     Now we are now working under our real uid
  */

  if (default_config)
    configname = make_filename (gnupg_homedir (),
                                GPG_AGENT_NAME EXTSEP_S "conf", NULL);

  argc = orig_argc;
  argv = orig_argv;
  pargs.argc = &argc;
  pargs.argv = &argv;
  pargs.flags=  1;  /* do not remove the args */
 next_pass:
  if (configname)
    {
      configlineno = 0;
      configfp = fopen (configname, "r");
      if (!configfp)
        {
          if (default_config)
            {
              if( parse_debug )
                log_info (_("Note: no default option file '%s'\n"),
                          configname );
              /* Save the default conf file name so that
                 reread_configuration is able to test whether the
                 config file has been created in the meantime.  */
              xfree (config_filename);
              config_filename = configname;
              configname = NULL;
	    }
          else
            {
              log_error (_("option file '%s': %s\n"),
                         configname, strerror(errno) );
              exit(2);
	    }
          xfree (configname);
          configname = NULL;
	}
      if (parse_debug && configname )
        log_info (_("reading options from '%s'\n"), configname );
      default_config = 0;
    }

  while (optfile_parse( configfp, configname, &configlineno, &pargs, opts) )
    {
      if (parse_rereadable_options (&pargs, 0))
        continue; /* Already handled */
      switch (pargs.r_opt)
        {
        case aGPGConfList: gpgconf_list = 1; break;
        case aGPGConfTest: gpgconf_list = 2; break;
        case aUseStandardSocketP: gpgconf_list = 3; break;
        case oBatch: opt.batch=1; break;

        case oDebugWait: debug_wait = pargs.r.ret_int; break;

        case oOptions:
          /* config files may not be nested (silently ignore them) */
          if (!configfp)
            {
		xfree(configname);
		configname = xstrdup(pargs.r.ret_str);
		goto next_pass;
	    }
          break;
        case oNoGreeting: /* Dummy option.  */ break;
        case oNoVerbose: opt.verbose = 0; break;
        case oNoOptions: break; /* no-options */
        case oHomedir: gnupg_set_homedir (pargs.r.ret_str); break;
        case oNoDetach: nodetach = 1; break;
        case oLogFile: logfile = pargs.r.ret_str; break;
        case oCsh: csh_style = 1; break;
        case oSh: csh_style = 0; break;
        case oServer: pipe_server = 1; break;
        case oDaemon: is_daemon = 1; break;

        case oDisplay: default_display = xstrdup (pargs.r.ret_str); break;
        case oTTYname: default_ttyname = xstrdup (pargs.r.ret_str); break;
        case oTTYtype: default_ttytype = xstrdup (pargs.r.ret_str); break;
        case oLCctype: default_lc_ctype = xstrdup (pargs.r.ret_str); break;
        case oLCmessages: default_lc_messages = xstrdup (pargs.r.ret_str);
          break;
        case oXauthority: default_xauthority = xstrdup (pargs.r.ret_str);
          break;

        case oUseStandardSocket:
        case oNoUseStandardSocket:
          obsolete_option (configname, configlineno, "use-standard-socket");
          break;

        case oFakedSystemTime:
          {
            time_t faked_time = isotime2epoch (pargs.r.ret_str);
            if (faked_time == (time_t)(-1))
              faked_time = (time_t)strtoul (pargs.r.ret_str, NULL, 10);
            gnupg_set_time (faked_time, 0);
          }
          break;

        case oKeepTTY: opt.keep_tty = 1; break;
        case oKeepDISPLAY: opt.keep_display = 1; break;

	case oSSHSupport:
          ssh_support = 1;
          break;
        case oPuttySupport:
#        ifdef HAVE_W32_SYSTEM
          putty_support = 1;
#        endif
          break;

        case oExtraSocket:
          opt.extra_socket = 1;  /* (1 = points into argv)  */
          socket_name_extra = pargs.r.ret_str;
          break;

        case oBrowserSocket:
          opt.browser_socket = 1;  /* (1 = points into argv)  */
          socket_name_browser = pargs.r.ret_str;
          break;

        case oDebugQuickRandom:
          /* Only used by the first stage command line parser.  */
          break;

        case oWriteEnvFile:
          obsolete_option (configname, configlineno, "write-env-file");
          break;

        default : pargs.err = configfp? 1:2; break;
	}
    }
  if (configfp)
    {
      fclose( configfp );
      configfp = NULL;
      /* Keep a copy of the name so that it can be read on SIGHUP. */
      if (config_filename != configname)
        {
          xfree (config_filename);
          config_filename = configname;
        }
      configname = NULL;
      goto next_pass;
    }

  xfree (configname);
  configname = NULL;
  if (log_get_errorcount(0))
    exit(2);

  finalize_rereadable_options ();

  /* Print a warning if an argument looks like an option.  */
  if (!opt.quiet && !(pargs.flags & ARGPARSE_FLAG_STOP_SEEN))
    {
      int i;

      for (i=0; i < argc; i++)
        if (argv[i][0] == '-' && argv[i][1] == '-')
          log_info (_("Note: '%s' is not considered an option\n"), argv[i]);
    }

#ifdef ENABLE_NLS
  /* gpg-agent usually does not output any messages because it runs in
     the background.  For log files it is acceptable to have messages
     always encoded in utf-8.  We switch here to utf-8, so that
     commands like --help still give native messages.  It is far
     easier to switch only once instead of for every message and it
     actually helps when more then one thread is active (avoids an
     extra copy step). */
    bind_textdomain_codeset (PACKAGE_GT, "UTF-8");
#endif

  if (!pipe_server && !is_daemon && !gpgconf_list)
    {
     /* We have been called without any options and thus we merely
        check whether an agent is already running.  We do this right
        here so that we don't clobber a logfile with this check but
        print the status directly to stderr. */
      opt.debug = 0;
      set_debug ();
      check_for_running_agent (0);
      agent_exit (0);
    }

  if (! opt.extra_socket)
    {
      opt.extra_socket = 1;
    }
  else if (socket_name_extra
           && (!strcmp (socket_name_extra, "none")
               || !strcmp (socket_name_extra, "/dev/null")))
    {
      /* User requested not to create this socket.  */
      opt.extra_socket = 0;
      socket_name_extra = NULL;
    }

  if (! opt.browser_socket)
    {
      opt.browser_socket = 1;
    }
  else if (socket_name_browser
           && (!strcmp (socket_name_browser, "none")
               || !strcmp (socket_name_browser, "/dev/null")))
    {
      /* User requested not to create this socket.  */
      opt.browser_socket = 0;
      socket_name_browser = NULL;
    }

  set_debug ();

  if (atexit (cleanup))
    {
      log_error ("atexit failed\n");
      cleanup ();
      exit (1);
    }

  /* Try to create missing directories. */
  create_directories ();

  if (debug_wait && pipe_server)
    {
      thread_init_once ();
      log_debug ("waiting for debugger - my pid is %u .....\n",
                 (unsigned int)getpid());
      gnupg_sleep (debug_wait);
      log_debug ("... okay\n");
    }

  if (gpgconf_list == 3)
    {
      /* We now use the standard socket always - return true for
         backward compatibility.  */
      agent_exit (0);
    }
  else if (gpgconf_list == 2)
    agent_exit (0);
  else if (gpgconf_list)
    {
      char *filename;
      char *filename_esc;

      /* List options and default values in the GPG Conf format.  */
      filename = make_filename (gnupg_homedir (),
                                GPG_AGENT_NAME EXTSEP_S "conf", NULL);
      filename_esc = percent_escape (filename, NULL);

      es_printf ("%s-%s.conf:%lu:\"%s\n",
                 GPGCONF_NAME, GPG_AGENT_NAME,
                 GC_OPT_FLAG_DEFAULT, filename_esc);
      xfree (filename);
      xfree (filename_esc);

      es_printf ("verbose:%lu:\n"
              "quiet:%lu:\n"
              "debug-level:%lu:\"none:\n"
              "log-file:%lu:\n",
              GC_OPT_FLAG_NONE|GC_OPT_FLAG_RUNTIME,
              GC_OPT_FLAG_NONE|GC_OPT_FLAG_RUNTIME,
              GC_OPT_FLAG_DEFAULT|GC_OPT_FLAG_RUNTIME,
              GC_OPT_FLAG_NONE|GC_OPT_FLAG_RUNTIME );
      es_printf ("default-cache-ttl:%lu:%d:\n",
              GC_OPT_FLAG_DEFAULT|GC_OPT_FLAG_RUNTIME, DEFAULT_CACHE_TTL );
      es_printf ("default-cache-ttl-ssh:%lu:%d:\n",
              GC_OPT_FLAG_DEFAULT|GC_OPT_FLAG_RUNTIME, DEFAULT_CACHE_TTL_SSH );
      es_printf ("max-cache-ttl:%lu:%d:\n",
              GC_OPT_FLAG_DEFAULT|GC_OPT_FLAG_RUNTIME, MAX_CACHE_TTL );
      es_printf ("max-cache-ttl-ssh:%lu:%d:\n",
              GC_OPT_FLAG_DEFAULT|GC_OPT_FLAG_RUNTIME, MAX_CACHE_TTL_SSH );
      es_printf ("enforce-passphrase-constraints:%lu:\n",
              GC_OPT_FLAG_NONE|GC_OPT_FLAG_RUNTIME);
      es_printf ("min-passphrase-len:%lu:%d:\n",
              GC_OPT_FLAG_DEFAULT|GC_OPT_FLAG_RUNTIME, MIN_PASSPHRASE_LEN );
      es_printf ("min-passphrase-nonalpha:%lu:%d:\n",
              GC_OPT_FLAG_DEFAULT|GC_OPT_FLAG_RUNTIME,
              MIN_PASSPHRASE_NONALPHA);
      es_printf ("check-passphrase-pattern:%lu:\n",
              GC_OPT_FLAG_DEFAULT|GC_OPT_FLAG_RUNTIME);
      es_printf ("max-passphrase-days:%lu:%d:\n",
              GC_OPT_FLAG_DEFAULT|GC_OPT_FLAG_RUNTIME,
              MAX_PASSPHRASE_DAYS);
      es_printf ("enable-passphrase-history:%lu:\n",
              GC_OPT_FLAG_NONE|GC_OPT_FLAG_RUNTIME);
      es_printf ("no-grab:%lu:\n",
              GC_OPT_FLAG_NONE|GC_OPT_FLAG_RUNTIME);
      es_printf ("ignore-cache-for-signing:%lu:\n",
              GC_OPT_FLAG_NONE|GC_OPT_FLAG_RUNTIME);
      es_printf ("no-allow-external-cache:%lu:\n",
              GC_OPT_FLAG_NONE|GC_OPT_FLAG_RUNTIME);
      es_printf ("no-allow-mark-trusted:%lu:\n",
              GC_OPT_FLAG_NONE|GC_OPT_FLAG_RUNTIME);
      es_printf ("disable-scdaemon:%lu:\n",
              GC_OPT_FLAG_NONE|GC_OPT_FLAG_RUNTIME);
      es_printf ("enable-ssh-support:%lu:\n", GC_OPT_FLAG_NONE);
#ifdef HAVE_W32_SYSTEM
      es_printf ("enable-putty-support:%lu:\n", GC_OPT_FLAG_NONE);
#endif
      es_printf ("no-allow-loopback-pinentry:%lu:\n",
              GC_OPT_FLAG_NONE|GC_OPT_FLAG_RUNTIME);
      es_printf ("allow-emacs-pinentry:%lu:\n",
                 GC_OPT_FLAG_NONE|GC_OPT_FLAG_RUNTIME);
      es_printf ("pinentry-timeout:%lu:0:\n",
                 GC_OPT_FLAG_DEFAULT|GC_OPT_FLAG_RUNTIME);

      agent_exit (0);
    }

  /* Now start with logging to a file if this is desired. */
  if (logfile)
    {
      log_set_file (logfile);
      log_set_prefix (NULL, (GPGRT_LOG_WITH_PREFIX
                             | GPGRT_LOG_WITH_TIME
                             | GPGRT_LOG_WITH_PID));
      current_logfile = xstrdup (logfile);
    }

  /* Make sure that we have a default ttyname. */
  if (!default_ttyname && gnupg_ttyname (1))
    default_ttyname = xstrdup (gnupg_ttyname (1));
  if (!default_ttytype && getenv ("TERM"))
    default_ttytype = xstrdup (getenv ("TERM"));


  if (pipe_server)
    {
      /* This is the simple pipe based server */
      ctrl_t ctrl;

      initialize_modules ();

      ctrl = xtrycalloc (1, sizeof *ctrl);
      if (!ctrl)
        {
          log_error ("error allocating connection control data: %s\n",
                     strerror (errno) );
          agent_exit (1);
        }
      ctrl->session_env = session_env_new ();
      if (!ctrl->session_env)
        {
          log_error ("error allocating session environment block: %s\n",
                     strerror (errno) );
          xfree (ctrl);
          agent_exit (1);
        }
      agent_init_default_ctrl (ctrl);
      start_command_handler (ctrl, GNUPG_INVALID_FD, GNUPG_INVALID_FD);
      agent_deinit_default_ctrl (ctrl);
      xfree (ctrl);
    }
  else if (!is_daemon)
    ; /* NOTREACHED */
  else
    { /* Regular server mode */
      gnupg_fd_t fd;
      gnupg_fd_t fd_extra = GNUPG_INVALID_FD;
      gnupg_fd_t fd_browser = GNUPG_INVALID_FD;
      gnupg_fd_t fd_ssh = GNUPG_INVALID_FD;
#ifndef HAVE_W32_SYSTEM
      pid_t pid;
#endif

      /* Remove the DISPLAY variable so that a pinentry does not
         default to a specific display.  There is still a default
         display when gpg-agent was started using --display or a
         client requested this using an OPTION command.  Note, that we
         don't do this when running in reverse daemon mode (i.e. when
         exec the program given as arguments). */
#ifndef HAVE_W32_SYSTEM
      if (!opt.keep_display && !argc)
        gnupg_unsetenv ("DISPLAY");
#endif

      /* Remove the INSIDE_EMACS variable so that a pinentry does not
         always try to interact with Emacs.  The variable is set when
         a client requested this using an OPTION command.  */
      gnupg_unsetenv ("INSIDE_EMACS");

      /* Create the sockets.  */
      socket_name = create_socket_name (GPG_AGENT_SOCK_NAME, 1);
      fd = create_server_socket (socket_name, 1, 0,
                                 &redir_socket_name, &socket_nonce);

      if (opt.extra_socket)
        {
          if (socket_name_extra)
            socket_name_extra = create_socket_name (socket_name_extra, 0);
          else
            socket_name_extra = create_socket_name
              /**/                (GPG_AGENT_EXTRA_SOCK_NAME, 1);
          opt.extra_socket = 2; /* Indicate that it has been malloced.  */
          fd_extra = create_server_socket (socket_name_extra, 0, 0,
                                           &redir_socket_name_extra,
                                           &socket_nonce_extra);
        }

      if (opt.browser_socket)
        {
          if (socket_name_browser)
            socket_name_browser = create_socket_name (socket_name_browser, 0);
          else
            socket_name_browser= create_socket_name
              /**/                 (GPG_AGENT_BROWSER_SOCK_NAME, 1);
          opt.browser_socket = 2; /* Indicate that it has been malloced.  */
          fd_browser = create_server_socket (socket_name_browser, 0, 0,
                                             &redir_socket_name_browser,
                                             &socket_nonce_browser);
        }

      socket_name_ssh = create_socket_name (GPG_AGENT_SSH_SOCK_NAME, 1);
      fd_ssh = create_server_socket (socket_name_ssh, 0, 1,
                                     &redir_socket_name_ssh,
                                     &socket_nonce_ssh);

      /* If we are going to exec a program in the parent, we record
         the PID, so that the child may check whether the program is
         still alive. */
      if (argc)
        parent_pid = getpid ();

      fflush (NULL);
#ifdef HAVE_W32_SYSTEM
      (void)csh_style;
      (void)nodetach;
#else /*!HAVE_W32_SYSTEM*/
      pid = fork ();
      if (pid == (pid_t)-1)
        {
          log_fatal ("fork failed: %s\n", strerror (errno) );
          exit (1);
        }
      else if (pid)
        { /* We are the parent */
          char *infostr_ssh_sock, *infostr_ssh_valid;

          /* Close the socket FD. */
          close (fd);

          /* The signal mask might not be correct right now and thus
             we restore it.  That is not strictly necessary but some
             programs falsely assume a cleared signal mask.  */

#ifdef HAVE_SIGPROCMASK
          if (startup_signal_mask_valid)
            {
              if (sigprocmask (SIG_SETMASK, &startup_signal_mask, NULL))
                log_error ("error restoring signal mask: %s\n",
                           strerror (errno));
            }
          else
            log_info ("no saved signal mask\n");
#endif /*HAVE_SIGPROCMASK*/

          /* Create the SSH info string if enabled. */
	  if (ssh_support)
	    {
	      if (asprintf (&infostr_ssh_sock, "SSH_AUTH_SOCK=%s",
			    socket_name_ssh) < 0)
		{
		  log_error ("out of core\n");
		  kill (pid, SIGTERM);
		  exit (1);
		}
	      if (asprintf (&infostr_ssh_valid, "gnupg_SSH_AUTH_SOCK_by=%lu",
			    (unsigned long)getpid()) < 0)
		{
		  log_error ("out of core\n");
		  kill (pid, SIGTERM);
		  exit (1);
		}
	    }

          *socket_name = 0; /* Don't let cleanup() remove the socket -
                               the child should do this from now on */
	  if (opt.extra_socket)
	    *socket_name_extra = 0;
	  if (opt.browser_socket)
	    *socket_name_browser = 0;
          *socket_name_ssh = 0;

          if (argc)
            { /* Run the program given on the commandline.  */
              if (ssh_support && (putenv (infostr_ssh_sock)
                                  || putenv (infostr_ssh_valid)))
                {
                  log_error ("failed to set environment: %s\n",
                             strerror (errno) );
                  kill (pid, SIGTERM );
                  exit (1);
                }

              /* Close all the file descriptors except the standard
                 ones and those open at startup.  We explicitly don't
                 close 0,1,2 in case something went wrong collecting
                 them at startup.  */
              close_all_fds (3, startup_fd_list);

              /* Run the command.  */
              execvp (argv[0], argv);
              log_error ("failed to run the command: %s\n", strerror (errno));
              kill (pid, SIGTERM);
              exit (1);
            }
          else
            {
              /* Print the environment string, so that the caller can use
                 shell's eval to set it */
              if (csh_style)
                {
		  if (ssh_support)
		    {
		      *strchr (infostr_ssh_sock, '=') = ' ';
		      es_printf ("setenv %s;\n", infostr_ssh_sock);
		    }
                }
              else
                {
		  if (ssh_support)
		    {
		      es_printf ("%s; export SSH_AUTH_SOCK;\n",
                                 infostr_ssh_sock);
		    }
                }
	      if (ssh_support)
		{
		  xfree (infostr_ssh_sock);
		  xfree (infostr_ssh_valid);
		}
              exit (0);
            }
          /*NOTREACHED*/
        } /* End parent */

      /*
         This is the child
       */

      initialize_modules ();

      /* Detach from tty and put process into a new session */
      if (!nodetach )
        {
          int i;
          unsigned int oldflags;

          /* Close stdin, stdout and stderr unless it is the log stream */
          for (i=0; i <= 2; i++)
            {
              if (!log_test_fd (i) && i != fd )
                {
                  if ( ! close (i)
                       && open ("/dev/null", i? O_WRONLY : O_RDONLY) == -1)
                    {
                      log_error ("failed to open '%s': %s\n",
                                 "/dev/null", strerror (errno));
                      cleanup ();
                      exit (1);
                    }
                }
            }
          if (setsid() == -1)
            {
              log_error ("setsid() failed: %s\n", strerror(errno) );
              cleanup ();
              exit (1);
            }

          log_get_prefix (&oldflags);
          log_set_prefix (NULL, oldflags | GPGRT_LOG_RUN_DETACHED);
          opt.running_detached = 1;
        }

      if (chdir("/"))
        {
          log_error ("chdir to / failed: %s\n", strerror (errno));
          exit (1);
        }

      {
        struct sigaction sa;

        sa.sa_handler = SIG_IGN;
        sigemptyset (&sa.sa_mask);
        sa.sa_flags = 0;
        sigaction (SIGPIPE, &sa, NULL);
      }
#endif /*!HAVE_W32_SYSTEM*/

      log_info ("%s %s started\n", strusage(11), strusage(13) );
      handle_connections (fd, fd_extra, fd_browser, fd_ssh);
      assuan_sock_close (fd);
    }

  return 0;
}


/* Exit entry point.  This function should be called instead of a
   plain exit.  */
void
agent_exit (int rc)
{
  /*FIXME: update_random_seed_file();*/

  /* We run our cleanup handler because that may close cipher contexts
     stored in secure memory and thus this needs to be done before we
     explicitly terminate secure memory.  */
  cleanup ();

#if 1
  /* at this time a bit annoying */
  if (opt.debug & DBG_MEMSTAT_VALUE)
    {
      gcry_control( GCRYCTL_DUMP_MEMORY_STATS );
      gcry_control( GCRYCTL_DUMP_RANDOM_STATS );
    }
  if (opt.debug)
    gcry_control (GCRYCTL_DUMP_SECMEM_STATS );
#endif
  gcry_control (GCRYCTL_TERM_SECMEM );
  rc = rc? rc : log_get_errorcount(0)? 2 : 0;
  exit (rc);
}


/* This is our callback function for gcrypt progress messages.  It is
   set once at startup and dispatches progress messages to the
   corresponding threads of the agent.  */
static void
agent_libgcrypt_progress_cb (void *data, const char *what, int printchar,
                             int current, int total)
{
  struct progress_dispatch_s *dispatch;
  npth_t mytid = npth_self ();

  (void)data;

  for (dispatch = progress_dispatch_list; dispatch; dispatch = dispatch->next)
    if (dispatch->ctrl && dispatch->tid == mytid)
      break;
  if (dispatch && dispatch->cb)
    dispatch->cb (dispatch->ctrl, what, printchar, current, total);
}


/* If a progress dispatcher callback has been associated with the
 * current connection unregister it.  */
static void
unregister_progress_cb (void)
{
  struct progress_dispatch_s *dispatch;
  npth_t mytid = npth_self ();

  for (dispatch = progress_dispatch_list; dispatch; dispatch = dispatch->next)
    if (dispatch->ctrl && dispatch->tid == mytid)
      break;
  if (dispatch)
    {
      dispatch->ctrl = NULL;
      dispatch->cb = NULL;
    }
}


/* Setup a progress callback CB for the current connection.  Using a
 * CB of NULL disables the callback.  */
void
agent_set_progress_cb (void (*cb)(ctrl_t ctrl, const char *what,
                                  int printchar, int current, int total),
                       ctrl_t ctrl)
{
  struct progress_dispatch_s *dispatch, *firstfree;
  npth_t mytid = npth_self ();

  firstfree = NULL;
  for (dispatch = progress_dispatch_list; dispatch; dispatch = dispatch->next)
    {
      if (dispatch->ctrl && dispatch->tid == mytid)
        break;
      if (!dispatch->ctrl && !firstfree)
        firstfree = dispatch;
    }
  if (!dispatch) /* None allocated: Reuse or allocate a new one.  */
    {
      if (firstfree)
        {
          dispatch = firstfree;
        }
      else if ((dispatch = xtrycalloc (1, sizeof *dispatch)))
        {
          dispatch->next = progress_dispatch_list;
          progress_dispatch_list = dispatch;
        }
      else
        {
          log_error ("error allocating new progress dispatcher slot: %s\n",
                     gpg_strerror (gpg_error_from_syserror ()));
          return;
        }
      dispatch->ctrl = ctrl;
      dispatch->tid = mytid;
    }

  dispatch->cb = cb;
}


/* Each thread has its own local variables conveyed by a control
   structure usually identified by an argument named CTRL.  This
   function is called immediately after allocating the control
   structure.  Its purpose is to setup the default values for that
   structure.  Note that some values may have already been set.  */
static void
agent_init_default_ctrl (ctrl_t ctrl)
{
  assert (ctrl->session_env);

  /* Note we ignore malloc errors because we can't do much about it
     and the request will fail anyway shortly after this
     initialization. */
  session_env_setenv (ctrl->session_env, "DISPLAY", default_display);
  session_env_setenv (ctrl->session_env, "GPG_TTY", default_ttyname);
  session_env_setenv (ctrl->session_env, "TERM", default_ttytype);
  session_env_setenv (ctrl->session_env, "XAUTHORITY", default_xauthority);
  session_env_setenv (ctrl->session_env, "PINENTRY_USER_DATA", NULL);

  if (ctrl->lc_ctype)
    xfree (ctrl->lc_ctype);
  ctrl->lc_ctype = default_lc_ctype? xtrystrdup (default_lc_ctype) : NULL;

  if (ctrl->lc_messages)
    xfree (ctrl->lc_messages);
  ctrl->lc_messages = default_lc_messages? xtrystrdup (default_lc_messages)
                                    /**/ : NULL;
  ctrl->cache_ttl_opt_preset = CACHE_TTL_OPT_PRESET;
}


/* Release all resources allocated by default in the control
   structure.  This is the counterpart to agent_init_default_ctrl.  */
static void
agent_deinit_default_ctrl (ctrl_t ctrl)
{
  unregister_progress_cb ();
  session_env_release (ctrl->session_env);

  if (ctrl->lc_ctype)
    xfree (ctrl->lc_ctype);
  if (ctrl->lc_messages)
    xfree (ctrl->lc_messages);
}


/* Because the ssh protocol does not send us information about the
   current TTY setting, we use this function to use those from startup
   or those explicitly set.  This is also used for the restricted mode
   where we ignore requests to change the environment.  */
gpg_error_t
agent_copy_startup_env (ctrl_t ctrl)
{
  static const char *names[] =
    {"GPG_TTY", "DISPLAY", "TERM", "XAUTHORITY", "PINENTRY_USER_DATA", NULL};
  gpg_error_t err = 0;
  int idx;
  const char *value;

  for (idx=0; !err && names[idx]; idx++)
      if ((value = session_env_getenv (opt.startup_env, names[idx])))
      err = session_env_setenv (ctrl->session_env, names[idx], value);

  if (!err && !ctrl->lc_ctype && opt.startup_lc_ctype)
    if (!(ctrl->lc_ctype = xtrystrdup (opt.startup_lc_ctype)))
      err = gpg_error_from_syserror ();

  if (!err && !ctrl->lc_messages && opt.startup_lc_messages)
    if (!(ctrl->lc_messages = xtrystrdup (opt.startup_lc_messages)))
      err = gpg_error_from_syserror ();

  if (err)
    log_error ("error setting default session environment: %s\n",
               gpg_strerror (err));

  return err;
}


/* Reread parts of the configuration.  Note, that this function is
   obviously not thread-safe and should only be called from the PTH
   signal handler.

   Fixme: Due to the way the argument parsing works, we create a
   memory leak here for all string type arguments.  There is currently
   no clean way to tell whether the memory for the argument has been
   allocated or points into the process' original arguments.  Unless
   we have a mechanism to tell this, we need to live on with this. */
static void
reread_configuration (void)
{
  ARGPARSE_ARGS pargs;
  FILE *fp;
  unsigned int configlineno = 0;
  int dummy;

  if (!config_filename)
    return; /* No config file. */

  fp = fopen (config_filename, "r");
  if (!fp)
    {
      log_info (_("option file '%s': %s\n"),
                config_filename, strerror(errno) );
      return;
    }

  parse_rereadable_options (NULL, 1); /* Start from the default values. */

  memset (&pargs, 0, sizeof pargs);
  dummy = 0;
  pargs.argc = &dummy;
  pargs.flags = 1;  /* do not remove the args */
  while (optfile_parse (fp, config_filename, &configlineno, &pargs, opts) )
    {
      if (pargs.r_opt < -1)
        pargs.err = 1; /* Print a warning. */
      else /* Try to parse this option - ignore unchangeable ones. */
        parse_rereadable_options (&pargs, 1);
    }
  fclose (fp);
  finalize_rereadable_options ();
  set_debug ();
}


/* Return the file name of the socket we are using for native
   requests.  */
const char *
get_agent_socket_name (void)
{
  const char *s = socket_name;

  return (s && *s)? s : NULL;
}

/* Return the file name of the socket we are using for SSH
   requests.  */
const char *
get_agent_ssh_socket_name (void)
{
  const char *s = socket_name_ssh;

  return (s && *s)? s : NULL;
}


/* Return the number of active connections. */
int
get_agent_active_connection_count (void)
{
  return active_connections;
}


/* Under W32, this function returns the handle of the scdaemon
   notification event.  Calling it the first time creates that
   event.  */
#if defined(HAVE_W32_SYSTEM) && !defined(HAVE_W32CE_SYSTEM)
void *
get_agent_scd_notify_event (void)
{
  static HANDLE the_event = INVALID_HANDLE_VALUE;

  if (the_event == INVALID_HANDLE_VALUE)
    {
      HANDLE h, h2;
      SECURITY_ATTRIBUTES sa = { sizeof (SECURITY_ATTRIBUTES), NULL, TRUE};

      /* We need to use a manual reset event object due to the way our
         w32-pth wait function works: If we would use an automatic
         reset event we are not able to figure out which handle has
         been signaled because at the time we single out the signaled
         handles using WFSO the event has already been reset due to
         the WFMO.  */
      h = CreateEvent (&sa, TRUE, FALSE, NULL);
      if (!h)
        log_error ("can't create scd notify event: %s\n", w32_strerror (-1) );
      else if (!DuplicateHandle (GetCurrentProcess(), h,
                                 GetCurrentProcess(), &h2,
                                 EVENT_MODIFY_STATE|SYNCHRONIZE, TRUE, 0))
        {
          log_error ("setting syncronize for scd notify event failed: %s\n",
                     w32_strerror (-1) );
          CloseHandle (h);
        }
      else
        {
          CloseHandle (h);
          the_event = h2;
        }
    }

  return the_event;
}
#endif /*HAVE_W32_SYSTEM && !HAVE_W32CE_SYSTEM*/



/* Create a name for the socket in the home directory as using
   STANDARD_NAME.  We also check for valid characters as well as
   against a maximum allowed length for a unix domain socket is done.
   The function terminates the process in case of an error.  Returns:
   Pointer to an allocated string with the absolute name of the socket
   used.  */
static char *
create_socket_name (char *standard_name, int with_homedir)
{
  char *name;

  if (with_homedir)
    name = make_filename (gnupg_socketdir (), standard_name, NULL);
  else
    name = make_filename (standard_name, NULL);
  if (strchr (name, PATHSEP_C))
    {
      log_error (("'%s' are not allowed in the socket name\n"), PATHSEP_S);
      agent_exit (2);
    }
  return name;
}



/* Create a Unix domain socket with NAME.  Returns the file descriptor
   or terminates the process in case of an error.  Note that this
   function needs to be used for the regular socket first (indicated
   by PRIMARY) and only then for the extra and the ssh sockets.  If
   the socket has been redirected the name of the real socket is
   stored as a malloced string at R_REDIR_NAME.  If CYGWIN is set a
   Cygwin compatible socket is created (Windows only). */
static gnupg_fd_t
create_server_socket (char *name, int primary, int cygwin,
                      char **r_redir_name, assuan_sock_nonce_t *nonce)
{
  struct sockaddr *addr;
  struct sockaddr_un *unaddr;
  socklen_t len;
  gnupg_fd_t fd;
  int rc;

  xfree (*r_redir_name);
  *r_redir_name = NULL;

  fd = assuan_sock_new (AF_UNIX, SOCK_STREAM, 0);
  if (fd == ASSUAN_INVALID_FD)
    {
      log_error (_("can't create socket: %s\n"), strerror (errno));
      *name = 0; /* Inhibit removal of the socket by cleanup(). */
      agent_exit (2);
    }

  if (cygwin)
    assuan_sock_set_flag (fd, "cygwin", 1);

  unaddr = xmalloc (sizeof *unaddr);
  addr = (struct sockaddr*)unaddr;

  {
    int redirected;

    if (assuan_sock_set_sockaddr_un (name, addr, &redirected))
      {
        if (errno == ENAMETOOLONG)
          log_error (_("socket name '%s' is too long\n"), name);
        else
          log_error ("error preparing socket '%s': %s\n",
                     name, gpg_strerror (gpg_error_from_syserror ()));
        *name = 0; /* Inhibit removal of the socket by cleanup(). */
        agent_exit (2);
      }
    if (redirected)
      {
        *r_redir_name = xstrdup (unaddr->sun_path);
        if (opt.verbose)
          log_info ("redirecting socket '%s' to '%s'\n", name, *r_redir_name);
      }
  }

  len = SUN_LEN (unaddr);
  rc = assuan_sock_bind (fd, addr, len);

  /* Our error code mapping on W32CE returns EEXIST thus we also test
     for this. */
  if (rc == -1
      && (errno == EADDRINUSE
#ifdef HAVE_W32_SYSTEM
          || errno == EEXIST
#endif
          ))
    {
      /* Check whether a gpg-agent is already running.  We do this
         test only if this is the primary socket.  For secondary
         sockets we assume that a test for gpg-agent has already been
         done and reuse the requested socket.  Testing the ssh-socket
         is not possible because at this point, though we know the new
         Assuan socket, the Assuan server and thus the ssh-agent
         server is not yet operational; this would lead to a hang.  */
      if (primary && !check_for_running_agent (1))
        {
          log_set_prefix (NULL, GPGRT_LOG_WITH_PREFIX);
          log_set_file (NULL);
          log_error (_("a gpg-agent is already running - "
                       "not starting a new one\n"));
          *name = 0; /* Inhibit removal of the socket by cleanup(). */
          assuan_sock_close (fd);
          agent_exit (2);
        }
      gnupg_remove (unaddr->sun_path);
      rc = assuan_sock_bind (fd, addr, len);
    }
  if (rc != -1 && (rc=assuan_sock_get_nonce (addr, len, nonce)))
    log_error (_("error getting nonce for the socket\n"));
  if (rc == -1)
    {
      /* We use gpg_strerror here because it allows us to get strings
         for some W32 socket error codes.  */
      log_error (_("error binding socket to '%s': %s\n"),
		 unaddr->sun_path,
                 gpg_strerror (gpg_error_from_syserror ()));

      assuan_sock_close (fd);
      *name = 0; /* Inhibit removal of the socket by cleanup(). */
      agent_exit (2);
    }

  if (gnupg_chmod (unaddr->sun_path, "-rwx"))
    log_error (_("can't set permissions of '%s': %s\n"),
               unaddr->sun_path, strerror (errno));

  if (listen (FD2INT(fd), 5 ) == -1)
    {
      log_error (_("listen() failed: %s\n"), strerror (errno));
      *name = 0; /* Inhibit removal of the socket by cleanup(). */
      assuan_sock_close (fd);
      agent_exit (2);
    }

  if (opt.verbose)
    log_info (_("listening on socket '%s'\n"), unaddr->sun_path);

  return fd;
}


/* Check that the directory for storing the private keys exists and
   create it if not.  This function won't fail as it is only a
   convenience function and not strictly necessary.  */
static void
create_private_keys_directory (const char *home)
{
  char *fname;
  struct stat statbuf;

  fname = make_filename (home, GNUPG_PRIVATE_KEYS_DIR, NULL);
  if (stat (fname, &statbuf) && errno == ENOENT)
    {
      if (gnupg_mkdir (fname, "-rwx"))
        log_error (_("can't create directory '%s': %s\n"),
                   fname, strerror (errno) );
      else if (!opt.quiet)
        log_info (_("directory '%s' created\n"), fname);
    }
  if (gnupg_chmod (fname, "-rwx"))
    log_error (_("can't set permissions of '%s': %s\n"),
               fname, strerror (errno));
  xfree (fname);
}


/* Create the directory only if the supplied directory name is the
   same as the default one.  This way we avoid to create arbitrary
   directories when a non-default home directory is used.  To cope
   with HOME, we compare only the suffix if we see that the default
   homedir does start with a tilde.  We don't stop here in case of
   problems because other functions will throw an error anyway.*/
static void
create_directories (void)
{
  struct stat statbuf;
  const char *defhome = standard_homedir ();
  char *home;

  home = make_filename (gnupg_homedir (), NULL);
  if ( stat (home, &statbuf) )
    {
      if (errno == ENOENT)
        {
          if (
#ifdef HAVE_W32_SYSTEM
              ( !compare_filenames (home, defhome) )
#else
              (*defhome == '~'
                && (strlen (home) >= strlen (defhome+1)
                    && !strcmp (home + strlen(home)
                                - strlen (defhome+1), defhome+1)))
               || (*defhome != '~' && !strcmp (home, defhome) )
#endif
               )
            {
              if (gnupg_mkdir (home, "-rwx"))
                log_error (_("can't create directory '%s': %s\n"),
                           home, strerror (errno) );
              else
                {
                  if (!opt.quiet)
                    log_info (_("directory '%s' created\n"), home);
                  create_private_keys_directory (home);
                }
            }
        }
      else
        log_error (_("stat() failed for '%s': %s\n"), home, strerror (errno));
    }
  else if ( !S_ISDIR(statbuf.st_mode))
    {
      log_error (_("can't use '%s' as home directory\n"), home);
    }
  else /* exists and is a directory. */
    {
      create_private_keys_directory (home);
    }
  xfree (home);
}



/* This is the worker for the ticker.  It is called every few seconds
   and may only do fast operations. */
static void
handle_tick (void)
{
  static time_t last_minute;

  if (!last_minute)
    last_minute = time (NULL);

  /* Check whether the scdaemon has died and cleanup in this case. */
  agent_scd_check_aliveness ();

  /* If we are running as a child of another process, check whether
     the parent is still alive and shutdown if not. */
#ifndef HAVE_W32_SYSTEM
  if (parent_pid != (pid_t)(-1))
    {
      if (kill (parent_pid, 0))
        {
          shutdown_pending = 2;
          log_info ("parent process died - shutting down\n");
          log_info ("%s %s stopped\n", strusage(11), strusage(13) );
          cleanup ();
          agent_exit (0);
        }
    }
#endif /*HAVE_W32_SYSTEM*/

  /* Code to be run from time to time.  */
#if CHECK_OWN_SOCKET_INTERVAL > 0
  if (last_minute + CHECK_OWN_SOCKET_INTERVAL <= time (NULL))
    {
      check_own_socket ();
      last_minute = time (NULL);
    }
#endif

}


/* A global function which allows us to call the reload stuff from
   other places too.  This is only used when build for W32.  */
void
agent_sighup_action (void)
{
  log_info ("SIGHUP received - "
            "re-reading configuration and flushing cache\n");

  agent_flush_cache ();
  reread_configuration ();
  agent_reload_trustlist ();
  /* We flush the module name cache so that after installing a
     "pinentry" binary that one can be used in case the
     "pinentry-basic" fallback was in use.  */
  gnupg_module_name_flush_some ();
}


/* A helper function to handle SIGUSR2.  */
static void
agent_sigusr2_action (void)
{
  if (opt.verbose)
    log_info ("SIGUSR2 received - updating card event counter\n");
  /* Nothing to check right now.  We only increment a counter.  */
  bump_card_eventcounter ();
}


#ifndef HAVE_W32_SYSTEM
/* The signal handler for this program.  It is expected to be run in
   its own trhead and not in the context of a signal handler.  */
static void
handle_signal (int signo)
{
  switch (signo)
    {
#ifndef HAVE_W32_SYSTEM
    case SIGHUP:
      agent_sighup_action ();
      break;

    case SIGUSR1:
      log_info ("SIGUSR1 received - printing internal information:\n");
      /* Fixme: We need to see how to integrate pth dumping into our
         logging system.  */
      /* pth_ctrl (PTH_CTRL_DUMPSTATE, log_get_stream ()); */
      agent_query_dump_state ();
      agent_scd_dump_state ();
      break;

    case SIGUSR2:
      agent_sigusr2_action ();
      break;

    case SIGTERM:
      if (!shutdown_pending)
        log_info ("SIGTERM received - shutting down ...\n");
      else
        log_info ("SIGTERM received - still %i open connections\n",
		  active_connections);
      shutdown_pending++;
      if (shutdown_pending > 2)
        {
          log_info ("shutdown forced\n");
          log_info ("%s %s stopped\n", strusage(11), strusage(13) );
          cleanup ();
          agent_exit (0);
	}
      break;

    case SIGINT:
      log_info ("SIGINT received - immediate shutdown\n");
      log_info( "%s %s stopped\n", strusage(11), strusage(13));
      cleanup ();
      agent_exit (0);
      break;
#endif
    default:
      log_info ("signal %d received - no action defined\n", signo);
    }
}
#endif

/* Check the nonce on a new connection.  This is a NOP unless we we
   are using our Unix domain socket emulation under Windows.  */
static int
check_nonce (ctrl_t ctrl, assuan_sock_nonce_t *nonce)
{
  if (assuan_sock_check_nonce (ctrl->thread_startup.fd, nonce))
    {
      log_info (_("error reading nonce on fd %d: %s\n"),
                FD2INT(ctrl->thread_startup.fd), strerror (errno));
      assuan_sock_close (ctrl->thread_startup.fd);
      xfree (ctrl);
      return -1;
    }
  else
    return 0;
}


#ifdef HAVE_W32_SYSTEM
/* The window message processing function for Putty.  Warning: This
   code runs as a native Windows thread.  Use of our own functions
   needs to be bracket with pth_leave/pth_enter. */
static LRESULT CALLBACK
putty_message_proc (HWND hwnd, UINT msg, WPARAM wparam, LPARAM lparam)
{
  int ret = 0;
  int w32rc;
  COPYDATASTRUCT *cds;
  const char *mapfile;
  HANDLE maphd;
  PSID mysid = NULL;
  PSID mapsid = NULL;
  void *data = NULL;
  PSECURITY_DESCRIPTOR psd = NULL;
  ctrl_t ctrl = NULL;

  if (msg != WM_COPYDATA)
    {
      return DefWindowProc (hwnd, msg, wparam, lparam);
    }

  cds = (COPYDATASTRUCT*)lparam;
  if (cds->dwData != PUTTY_IPC_MAGIC)
    return 0;  /* Ignore data with the wrong magic.  */
  mapfile = cds->lpData;
  if (!cds->cbData || mapfile[cds->cbData - 1])
    return 0;  /* Ignore empty and non-properly terminated strings.  */

  if (DBG_IPC)
    {
      npth_protect ();
      log_debug ("ssh map file '%s'", mapfile);
      npth_unprotect ();
    }

  maphd = OpenFileMapping (FILE_MAP_ALL_ACCESS, FALSE, mapfile);
  if (DBG_IPC)
    {
      npth_protect ();
      log_debug ("ssh map handle %p\n", maphd);
      npth_unprotect ();
    }

  if (!maphd || maphd == INVALID_HANDLE_VALUE)
    return 0;

  npth_protect ();

  mysid = w32_get_user_sid ();
  if (!mysid)
    {
      log_error ("error getting my sid\n");
      goto leave;
    }

  w32rc = GetSecurityInfo (maphd, SE_KERNEL_OBJECT,
                           OWNER_SECURITY_INFORMATION,
                           &mapsid, NULL, NULL, NULL,
                           &psd);
  if (w32rc)
    {
      log_error ("error getting sid of ssh map file: rc=%d", w32rc);
      goto leave;
    }

  if (DBG_IPC)
    {
      char *sidstr;

      if (!ConvertSidToStringSid (mysid, &sidstr))
        sidstr = NULL;
      log_debug ("          my sid: '%s'", sidstr? sidstr: "[error]");
      LocalFree (sidstr);
      if (!ConvertSidToStringSid (mapsid, &sidstr))
        sidstr = NULL;
      log_debug ("ssh map file sid: '%s'", sidstr? sidstr: "[error]");
      LocalFree (sidstr);
    }

  if (!EqualSid (mysid, mapsid))
    {
      log_error ("ssh map file has a non-matching sid\n");
      goto leave;
    }

  data = MapViewOfFile (maphd, FILE_MAP_ALL_ACCESS, 0, 0, 0);
  if (DBG_IPC)
    log_debug ("ssh IPC buffer at %p\n", data);
  if (!data)
    goto leave;

  /* log_printhex ("request:", data, 20); */

  ctrl = xtrycalloc (1, sizeof *ctrl);
  if (!ctrl)
    {
      log_error ("error allocating connection control data: %s\n",
                 strerror (errno) );
      goto leave;
    }
  ctrl->session_env = session_env_new ();
  if (!ctrl->session_env)
    {
      log_error ("error allocating session environment block: %s\n",
                 strerror (errno) );
      goto leave;
    }

  agent_init_default_ctrl (ctrl);
  if (!serve_mmapped_ssh_request (ctrl, data, PUTTY_IPC_MAXLEN))
    ret = 1; /* Valid ssh message has been constructed.  */
  agent_deinit_default_ctrl (ctrl);
  /* log_printhex ("  reply:", data, 20); */

 leave:
  xfree (ctrl);
  if (data)
    UnmapViewOfFile (data);
  xfree (mapsid);
  if (psd)
    LocalFree (psd);
  xfree (mysid);
  CloseHandle (maphd);

  npth_unprotect ();

  return ret;
}
#endif /*HAVE_W32_SYSTEM*/


#ifdef HAVE_W32_SYSTEM
/* The thread handling Putty's IPC requests.  */
static void *
putty_message_thread (void *arg)
{
  WNDCLASS wndwclass = {0, putty_message_proc, 0, 0,
                        NULL, NULL, NULL, NULL, NULL, "Pageant"};
  HWND hwnd;
  MSG msg;

  (void)arg;

  if (opt.verbose)
    log_info ("putty message loop thread started\n");

  /* The message loop runs as thread independent from our nPth system.
     This also means that we need to make sure that we switch back to
     our system before calling any no-windows function.  */
  npth_unprotect ();

  /* First create a window to make sure that a message queue exists
     for this thread.  */
  if (!RegisterClass (&wndwclass))
    {
      npth_protect ();
      log_error ("error registering Pageant window class");
      return NULL;
    }
  hwnd = CreateWindowEx (0, "Pageant", "Pageant", 0,
                         0, 0, 0, 0,
                         HWND_MESSAGE,  /* hWndParent */
                         NULL,          /* hWndMenu   */
                         NULL,          /* hInstance  */
                         NULL);         /* lpParm     */
  if (!hwnd)
    {
      npth_protect ();
      log_error ("error creating Pageant window");
      return NULL;
    }

  while (GetMessage(&msg, NULL, 0, 0))
    {
      TranslateMessage(&msg);
      DispatchMessage(&msg);
    }

  /* Back to nPth.  */
  npth_protect ();

  if (opt.verbose)
    log_info ("putty message loop thread stopped\n");
  return NULL;
}
#endif /*HAVE_W32_SYSTEM*/


static void *
do_start_connection_thread (ctrl_t ctrl)
{
  active_connections++;
  agent_init_default_ctrl (ctrl);
  if (opt.verbose && !DBG_IPC)
    log_info (_("handler 0x%lx for fd %d started\n"),
              (unsigned long) npth_self(), FD2INT(ctrl->thread_startup.fd));

  start_command_handler (ctrl, GNUPG_INVALID_FD, ctrl->thread_startup.fd);
  if (opt.verbose && !DBG_IPC)
    log_info (_("handler 0x%lx for fd %d terminated\n"),
              (unsigned long) npth_self(), FD2INT(ctrl->thread_startup.fd));

  agent_deinit_default_ctrl (ctrl);
  xfree (ctrl);
  active_connections--;
  return NULL;
}


/* This is the standard connection thread's main function.  */
static void *
start_connection_thread_std (void *arg)
{
  ctrl_t ctrl = arg;

  if (check_nonce (ctrl, &socket_nonce))
    {
      log_error ("handler 0x%lx nonce check FAILED\n",
                 (unsigned long) npth_self());
      return NULL;
    }

  return do_start_connection_thread (ctrl);
}


/* This is the extra socket connection thread's main function.  */
static void *
start_connection_thread_extra (void *arg)
{
  ctrl_t ctrl = arg;

  if (check_nonce (ctrl, &socket_nonce_extra))
    {
      log_error ("handler 0x%lx nonce check FAILED\n",
                 (unsigned long) npth_self());
      return NULL;
    }

  ctrl->restricted = 1;
  return do_start_connection_thread (ctrl);
}


/* This is the browser socket connection thread's main function.  */
static void *
start_connection_thread_browser (void *arg)
{
  ctrl_t ctrl = arg;

  if (check_nonce (ctrl, &socket_nonce_browser))
    {
      log_error ("handler 0x%lx nonce check FAILED\n",
                 (unsigned long) npth_self());
      return NULL;
    }

  ctrl->restricted = 2;
  return do_start_connection_thread (ctrl);
}


/* This is the ssh connection thread's main function.  */
static void *
start_connection_thread_ssh (void *arg)
{
  ctrl_t ctrl = arg;

  if (check_nonce (ctrl, &socket_nonce_ssh))
    return NULL;

  active_connections++;
  agent_init_default_ctrl (ctrl);
  if (opt.verbose)
    log_info (_("ssh handler 0x%lx for fd %d started\n"),
              (unsigned long) npth_self(), FD2INT(ctrl->thread_startup.fd));

  start_command_handler_ssh (ctrl, ctrl->thread_startup.fd);
  if (opt.verbose)
    log_info (_("ssh handler 0x%lx for fd %d terminated\n"),
              (unsigned long) npth_self(), FD2INT(ctrl->thread_startup.fd));

  agent_deinit_default_ctrl (ctrl);
  xfree (ctrl);
  active_connections--;
  return NULL;
}


#ifdef HAVE_INOTIFY_INIT
/* Read an inotify event and return true if it matches NAME.  */
static int
my_inotify_is_name (int fd, const char *name)
{
  union {
    struct inotify_event ev;
    char _buf[sizeof (struct inotify_event) + 100 + 1];
  } buf;
  int n;

  n = npth_read (fd, &buf, sizeof buf);
  if (n < sizeof (struct inotify_event))
    return 0;
  if (buf.ev.len < strlen (name)+1)
    return 0;
  if (strcmp (buf.ev.name, name))
    return 0; /* Not the desired file.  */

  return 1; /* Found.  */
}
#endif /*HAVE_INOTIFY_INIT*/



/* Connection handler loop.  Wait for connection requests and spawn a
   thread after accepting a connection.  */
static void
handle_connections (gnupg_fd_t listen_fd,
                    gnupg_fd_t listen_fd_extra,
                    gnupg_fd_t listen_fd_browser,
                    gnupg_fd_t listen_fd_ssh)
{
  npth_attr_t tattr;
  struct sockaddr_un paddr;
  socklen_t plen;
  fd_set fdset, read_fdset;
  int ret;
  gnupg_fd_t fd;
  int nfd;
  int saved_errno;
  struct timespec abstime;
  struct timespec curtime;
  struct timespec timeout;
#ifdef HAVE_W32_SYSTEM
  HANDLE events[2];
  unsigned int events_set;
#endif
#ifdef HAVE_INOTIFY_INIT
  int my_inotify_fd;
#endif /*HAVE_INOTIFY_INIT*/
  struct {
    const char *name;
    void *(*func) (void *arg);
    gnupg_fd_t l_fd;
  } listentbl[] = {
    { "std",     start_connection_thread_std   },
    { "extra",   start_connection_thread_extra },
    { "browser", start_connection_thread_browser },
    { "ssh",    start_connection_thread_ssh   }
  };


  ret = npth_attr_init(&tattr);
  if (ret)
    log_fatal ("error allocating thread attributes: %s\n",
	       strerror (ret));
  npth_attr_setdetachstate (&tattr, NPTH_CREATE_DETACHED);

#ifndef HAVE_W32_SYSTEM
  npth_sigev_init ();
  npth_sigev_add (SIGHUP);
  npth_sigev_add (SIGUSR1);
  npth_sigev_add (SIGUSR2);
  npth_sigev_add (SIGINT);
  npth_sigev_add (SIGTERM);
  npth_sigev_fini ();
#else
# ifdef HAVE_W32CE_SYSTEM
  /* Use a dummy event. */
  sigs = 0;
  ev = pth_event (PTH_EVENT_SIGS, &sigs, &signo);
# else
  events[0] = get_agent_scd_notify_event ();
  events[1] = INVALID_HANDLE_VALUE;
# endif
#endif

#ifdef HAVE_INOTIFY_INIT
  if (disable_check_own_socket)
    my_inotify_fd = -1;
  else if ((my_inotify_fd = inotify_init ()) == -1)
    log_info ("error enabling fast daemon termination: %s\n",
              strerror (errno));
  else
    {
      /* We need to watch the directory for the file because there
       * won't be an IN_DELETE_SELF for a socket file.  */
      char *slash = strrchr (socket_name, '/');
      log_assert (slash && slash[1]);
      *slash = 0;
      if (inotify_add_watch (my_inotify_fd, socket_name, IN_DELETE) == -1)
        {
          close (my_inotify_fd);
          my_inotify_fd = -1;
        }
      *slash = '/';
    }
#endif /*HAVE_INOTIFY_INIT*/

  /* On Windows we need to fire up a separate thread to listen for
     requests from Putty (an SSH client), so we can replace Putty's
     Pageant (its ssh-agent implementation). */
#ifdef HAVE_W32_SYSTEM
  if (putty_support)
    {
      npth_t thread;

      ret = npth_create (&thread, &tattr, putty_message_thread, NULL);
      if (ret)
        {
          log_error ("error spawning putty message loop: %s\n", strerror (ret));
        }
    }
#endif /*HAVE_W32_SYSTEM*/

  /* Set a flag to tell call-scd.c that it may enable event
     notifications.  */
  opt.sigusr2_enabled = 1;

  FD_ZERO (&fdset);
  FD_SET (FD2INT (listen_fd), &fdset);
  nfd = FD2INT (listen_fd);
  if (listen_fd_extra != GNUPG_INVALID_FD)
    {
      FD_SET ( FD2INT(listen_fd_extra), &fdset);
      if (FD2INT (listen_fd_extra) > nfd)
        nfd = FD2INT (listen_fd_extra);
    }
  if (listen_fd_browser != GNUPG_INVALID_FD)
    {
      FD_SET ( FD2INT(listen_fd_browser), &fdset);
      if (FD2INT (listen_fd_browser) > nfd)
        nfd = FD2INT (listen_fd_browser);
    }
  if (listen_fd_ssh != GNUPG_INVALID_FD)
    {
      FD_SET ( FD2INT(listen_fd_ssh), &fdset);
      if (FD2INT (listen_fd_ssh) > nfd)
        nfd = FD2INT (listen_fd_ssh);
    }
#ifdef HAVE_INOTIFY_INIT
  if (my_inotify_fd != -1)
    {
      FD_SET (my_inotify_fd, &fdset);
      if (my_inotify_fd > nfd)
        nfd = my_inotify_fd;
    }
#endif /*HAVE_INOTIFY_INIT*/

  listentbl[0].l_fd = listen_fd;
  listentbl[1].l_fd = listen_fd_extra;
  listentbl[2].l_fd = listen_fd_browser;
  listentbl[3].l_fd = listen_fd_ssh;

  npth_clock_gettime (&abstime);
  abstime.tv_sec += TIMERTICK_INTERVAL;

  for (;;)
    {
      /* Shutdown test.  */
      if (shutdown_pending)
        {
          if (active_connections == 0)
            break; /* ready */

          /* Do not accept new connections but keep on running the
             loop to cope with the timer events.  */
          FD_ZERO (&fdset);
	}

      /* POSIX says that fd_set should be implemented as a structure,
         thus a simple assignment is fine to copy the entire set.  */
      read_fdset = fdset;

      npth_clock_gettime (&curtime);
      if (!(npth_timercmp (&curtime, &abstime, <)))
	{
	  /* Timeout.  */
	  handle_tick ();
	  npth_clock_gettime (&abstime);
	  abstime.tv_sec += TIMERTICK_INTERVAL;
	}
      npth_timersub (&abstime, &curtime, &timeout);

#ifndef HAVE_W32_SYSTEM
      ret = npth_pselect (nfd+1, &read_fdset, NULL, NULL, &timeout,
                          npth_sigev_sigmask ());
      saved_errno = errno;

      {
        int signo;
        while (npth_sigev_get_pending (&signo))
          handle_signal (signo);
      }
#else
      ret = npth_eselect (nfd+1, &read_fdset, NULL, NULL, &timeout,
                          events, &events_set);
      saved_errno = errno;

      /* This is valid even if npth_eselect returns an error.  */
      if (events_set & 1)
	agent_sigusr2_action ();
#endif

      if (ret == -1 && saved_errno != EINTR)
	{
          log_error (_("npth_pselect failed: %s - waiting 1s\n"),
                     strerror (saved_errno));
          npth_sleep (1);
          continue;
	}
      if (ret <= 0)
	/* Interrupt or timeout.  Will be handled when calculating the
	   next timeout.  */
	continue;

      if (!shutdown_pending)
        {
          int idx;
          ctrl_t ctrl;
          npth_t thread;

#ifdef HAVE_INOTIFY_INIT
          if (my_inotify_fd != -1 && FD_ISSET (my_inotify_fd, &read_fdset)
              && my_inotify_is_name (my_inotify_fd, GPG_AGENT_SOCK_NAME))
            {
              shutdown_pending = 1;
              log_info ("socket file has been removed - shutting down\n");
            }
#endif /*HAVE_INOTIFY_INIT*/

          for (idx=0; idx < DIM(listentbl); idx++)
            {
              if (listentbl[idx].l_fd == GNUPG_INVALID_FD)
                continue;
              if (!FD_ISSET (FD2INT (listentbl[idx].l_fd), &read_fdset))
                continue;

              plen = sizeof paddr;
              fd = INT2FD (npth_accept (FD2INT(listentbl[idx].l_fd),
                                        (struct sockaddr *)&paddr, &plen));
              if (fd == GNUPG_INVALID_FD)
                {
                  log_error ("accept failed for %s: %s\n",
                             listentbl[idx].name, strerror (errno));
                }
              else if ( !(ctrl = xtrycalloc (1, sizeof *ctrl)))
                {
                  log_error ("error allocating connection data for %s: %s\n",
                             listentbl[idx].name, strerror (errno) );
                  assuan_sock_close (fd);
                }
              else if ( !(ctrl->session_env = session_env_new ()))
                {
                  log_error ("error allocating session env block for %s: %s\n",
                             listentbl[idx].name, strerror (errno) );
                  xfree (ctrl);
                  assuan_sock_close (fd);
                }
              else
                {
                  ctrl->thread_startup.fd = fd;
                  ret = npth_create (&thread, &tattr,
                                     listentbl[idx].func, ctrl);
                  if (ret)
                    {
                      log_error ("error spawning connection handler for %s:"
                                 " %s\n", listentbl[idx].name, strerror (ret));
                      assuan_sock_close (fd);
                      xfree (ctrl);
                    }
                }
              fd = GNUPG_INVALID_FD;
            }
        }
    }

#ifdef HAVE_INOTIFY_INIT
  if (my_inotify_fd != -1)
    close (my_inotify_fd);
#endif /*HAVE_INOTIFY_INIT*/
  cleanup ();
  log_info (_("%s %s stopped\n"), strusage(11), strusage(13));
  npth_attr_destroy (&tattr);
}



/* Helper for check_own_socket.  */
static gpg_error_t
check_own_socket_pid_cb (void *opaque, const void *buffer, size_t length)
{
  membuf_t *mb = opaque;
  put_membuf (mb, buffer, length);
  return 0;
}


/* The thread running the actual check.  We need to run this in a
   separate thread so that check_own_thread can be called from the
   timer tick.  */
static void *
check_own_socket_thread (void *arg)
{
  int rc;
  char *sockname = arg;
  assuan_context_t ctx = NULL;
  membuf_t mb;
  char *buffer;

  check_own_socket_running++;

  rc = assuan_new (&ctx);
  if (rc)
    {
      log_error ("can't allocate assuan context: %s\n", gpg_strerror (rc));
      goto leave;
    }
  assuan_set_flag (ctx, ASSUAN_NO_LOGGING, 1);

  rc = assuan_socket_connect (ctx, sockname, (pid_t)(-1), 0);
  if (rc)
    {
      log_error ("can't connect my own socket: %s\n", gpg_strerror (rc));
      goto leave;
    }

  init_membuf (&mb, 100);
  rc = assuan_transact (ctx, "GETINFO pid", check_own_socket_pid_cb, &mb,
                        NULL, NULL, NULL, NULL);
  put_membuf (&mb, "", 1);
  buffer = get_membuf (&mb, NULL);
  if (rc || !buffer)
    {
      log_error ("sending command \"%s\" to my own socket failed: %s\n",
                 "GETINFO pid", gpg_strerror (rc));
      rc = 1;
    }
  else if ( (pid_t)strtoul (buffer, NULL, 10) != getpid ())
    {
      log_error ("socket is now serviced by another server\n");
      rc = 1;
    }
  else if (opt.verbose > 1)
    log_error ("socket is still served by this server\n");

  xfree (buffer);

 leave:
  xfree (sockname);
  if (ctx)
    assuan_release (ctx);
  if (rc)
    {
      /* We may not remove the socket as it is now in use by another
         server.  Setting the name to empty does this.  */
      if (socket_name)
        *socket_name = 0;
      if (socket_name_ssh)
        *socket_name_ssh = 0;
      shutdown_pending = 2;
      log_info ("this process is useless - shutting down\n");
    }
  check_own_socket_running--;
  return NULL;
}


/* Check whether we are still listening on our own socket.  In case
   another gpg-agent process started after us has taken ownership of
   our socket, we would linger around without any real task.  Thus we
   better check once in a while whether we are really needed.  */
static void
check_own_socket (void)
{
  char *sockname;
  npth_t thread;
  npth_attr_t tattr;
  int err;

  if (disable_check_own_socket)
    return;

  if (check_own_socket_running || shutdown_pending)
    return;  /* Still running or already shutting down.  */

  sockname = make_filename_try (gnupg_socketdir (), GPG_AGENT_SOCK_NAME, NULL);
  if (!sockname)
    return; /* Out of memory.  */

  err = npth_attr_init (&tattr);
  if (err)
    return;
  npth_attr_setdetachstate (&tattr, NPTH_CREATE_DETACHED);
  err = npth_create (&thread, &tattr, check_own_socket_thread, sockname);
  if (err)
    log_error ("error spawning check_own_socket_thread: %s\n", strerror (err));
  npth_attr_destroy (&tattr);
}



/* Figure out whether an agent is available and running. Prints an
   error if not.  If SILENT is true, no messages are printed.
   Returns 0 if the agent is running. */
static int
check_for_running_agent (int silent)
{
  gpg_error_t err;
  char *sockname;
  assuan_context_t ctx = NULL;

  sockname = make_filename_try (gnupg_socketdir (), GPG_AGENT_SOCK_NAME, NULL);
  if (!sockname)
    return gpg_error_from_syserror ();

  err = assuan_new (&ctx);
  if (!err)
    err = assuan_socket_connect (ctx, sockname, (pid_t)(-1), 0);
  xfree (sockname);
  if (err)
    {
      if (!silent)
        log_error (_("no gpg-agent running in this session\n"));

      if (ctx)
	assuan_release (ctx);
      return -1;
    }

  if (!opt.quiet && !silent)
    log_info ("gpg-agent running and available\n");

  assuan_release (ctx);
  return 0;
}