/* asshelp.c - Helper functions for Assuan

 * Copyright (C) 2002, 2004, 2007, 2009, 2010 Free Software Foundation, Inc.

 *

 * This file is part of GnuPG.

 *

 * This file is free software; you can redistribute it and/or modify

 * it under the terms of either

 *

 *   - the GNU Lesser General Public License as published by the Free

 *     Software Foundation; either version 3 of the License, or (at

 *     your option) any later version.

 *

 * or

 *

 *   - the GNU General Public License as published by the Free

 *     Software Foundation; either version 2 of the License, or (at

 *     your option) any later version.

 *

 * or both in parallel, as here.

 *

 * This file 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 <https://www.gnu.org/licenses/>.

 */

#include <config.h>

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <unistd.h>

#include <errno.h>

#ifdef HAVE_LOCALE_H

#include <locale.h>

#endif

#include "i18n.h"

#include "util.h"

#include "sysutils.h"

#include "status.h"

#include "membuf.h"

#include "asshelp.h"

/* The type we use for lock_agent_spawning.  */

#ifdef HAVE_W32_SYSTEM

# define lock_spawn_t HANDLE

#else

# define lock_spawn_t dotlock_t

#endif

/* The time we wait until the agent or the dirmngr are ready for

   operation after we started them before giving up.  */

#define SECS_TO_WAIT_FOR_AGENT 8

#define SECS_TO_WAIT_FOR_KEYBOXD 8

#define SECS_TO_WAIT_FOR_DIRMNGR 8

/* A bitfield that specifies the assuan categories to log.  This is

   identical to the default log handler of libassuan.  We need to do

   it ourselves because we use a custom log handler and want to use

   the same assuan variables to select the categories to log. */

static int log_cats;

#define TEST_LOG_CAT(x) (!! (log_cats & (1 << (x - 1))))

/* The assuan log monitor used to temporary inhibit log messages from

 * assuan.  */

static int (*my_log_monitor) (assuan_context_t ctx,

                              unsigned int cat,

                              const char *msg);

static int

my_libassuan_log_handler (assuan_context_t ctx, void *hook,

                          unsigned int cat, const char *msg)

{

  unsigned int dbgval;

  if (! TEST_LOG_CAT (cat))

    return 0;

  dbgval = hook? *(unsigned int*)hook : 0;

  if (!(dbgval & 1024))

    return 0; /* Assuan debugging is not enabled.  */

  if (ctx && my_log_monitor && !my_log_monitor (ctx, cat, msg))

    return 0; /* Temporary disabled.  */

  if (msg)

    log_string (GPGRT_LOGLVL_DEBUG, msg);

  return 1;

}

/* Setup libassuan to use our own logging functions.  Should be used

   early at startup.  */

void

setup_libassuan_logging (unsigned int *debug_var_address,

                         int (*log_monitor)(assuan_context_t ctx,

                                            unsigned int cat,

                                            const char *msg))

{

  char *flagstr;

  flagstr = getenv ("ASSUAN_DEBUG");

  if (flagstr)

    log_cats = atoi (flagstr);

  else /* Default to log the control channel.  */

    log_cats = (1 << (ASSUAN_LOG_CONTROL - 1));

  my_log_monitor = log_monitor;

  assuan_set_log_cb (my_libassuan_log_handler, debug_var_address);

}

/* Change the Libassuan log categories to those given by NEWCATS.

   NEWCATS is 0 the default category of ASSUAN_LOG_CONTROL is

   selected.  Note, that setup_libassuan_logging overrides the values

   given here.  */

void

set_libassuan_log_cats (unsigned int newcats)

{

  if (newcats)

    log_cats = newcats;

  else /* Default to log the control channel.  */

    log_cats = (1 << (ASSUAN_LOG_CONTROL - 1));

}

/* Get the last Windows error from an Assuan socket function and print

 * the raw error code using log_info.  */

void

log_libassuan_system_error (assuan_fd_t fd)

{

  int w32err = 0;

  if (assuan_sock_get_flag (fd, "w32_error", &w32err))

    w32err = -1;  /* Old Libassuan or not Windows.  */

  if (w32err != -1)

    log_info ("system error code: %d (0x%x)\n", w32err, w32err);

}

static gpg_error_t

send_one_option (assuan_context_t ctx, gpg_err_source_t errsource,

                 const char *name, const char *value, int use_putenv)

{

  gpg_error_t err;

  char *optstr;

  (void)errsource;

  if (!value || !*value)

    err = 0;  /* Avoid sending empty strings.  */

  else if (asprintf (&optstr, "OPTION %s%s=%s",

                     use_putenv? "putenv=":"", name, value) < 0)

    err = gpg_error_from_syserror ();

  else

    {

      err = assuan_transact (ctx, optstr, NULL, NULL, NULL, NULL, NULL, NULL);

      xfree (optstr);

    }

  return err;

}

/* Send the assuan commands pertaining to the pinentry environment.  The

   OPT_* arguments are optional and may be used to override the

   defaults taken from the current locale. */

gpg_error_t

send_pinentry_environment (assuan_context_t ctx,

                           gpg_err_source_t errsource,

                           const char *opt_lc_ctype,

                           const char *opt_lc_messages,

                           session_env_t session_env)

{

  gpg_error_t err = 0;

#if defined(HAVE_SETLOCALE)

  char *old_lc = NULL;

#endif

  char *dft_lc = NULL;

  const char *dft_ttyname;

  int iterator;

  const char *name, *assname, *value;

  int is_default;

  iterator = 0;

  while ((name = session_env_list_stdenvnames (&iterator, &assname)))

    {

      value = session_env_getenv_or_default (session_env, name, NULL);

      if (!value)

        continue;

      if (assname)

        err = send_one_option (ctx, errsource, assname, value, 0);

      else

        {

          err = send_one_option (ctx, errsource, name, value, 1);

          if (gpg_err_code (err) == GPG_ERR_UNKNOWN_OPTION)

            err = 0;  /* Server too old; can't pass the new envvars.  */

        }

      if (err)

        return err;

    }

  dft_ttyname = session_env_getenv_or_default (session_env, "GPG_TTY",

                                               &is_default);

  if (dft_ttyname && !is_default)

    dft_ttyname = NULL;  /* We need the default value.  */

  /* Send the value for LC_CTYPE.  */

#if defined(HAVE_SETLOCALE) && defined(LC_CTYPE)

  old_lc = setlocale (LC_CTYPE, NULL);

  if (old_lc)

    {

      old_lc = xtrystrdup (old_lc);

      if (!old_lc)

        return gpg_error_from_syserror ();

    }

  dft_lc = setlocale (LC_CTYPE, "");

#endif

  if (opt_lc_ctype || (dft_ttyname && dft_lc))

    {

      err = send_one_option (ctx, errsource, "lc-ctype",

                             opt_lc_ctype ? opt_lc_ctype : dft_lc, 0);

    }

#if defined(HAVE_SETLOCALE) && defined(LC_CTYPE)

  if (old_lc)

    {

      setlocale (LC_CTYPE, old_lc);

      xfree (old_lc);

    }

#endif

  if (err)

    return err;

  /* Send the value for LC_MESSAGES.  */

#if defined(HAVE_SETLOCALE) && defined(LC_MESSAGES)

  old_lc = setlocale (LC_MESSAGES, NULL);

  if (old_lc)

    {

      old_lc = xtrystrdup (old_lc);

      if (!old_lc)

        return gpg_error_from_syserror ();

    }

  dft_lc = setlocale (LC_MESSAGES, "");

#endif

  if (opt_lc_messages || (dft_ttyname && dft_lc))

    {

      err = send_one_option (ctx, errsource, "lc-messages",

                             opt_lc_messages ? opt_lc_messages : dft_lc, 0);

    }

#if defined(HAVE_SETLOCALE) && defined(LC_MESSAGES)

  if (old_lc)

    {

      setlocale (LC_MESSAGES, old_lc);

      xfree (old_lc);

    }

#endif

  if (err)

    return err;

  return 0;

}

/* Lock a spawning process.  The caller needs to provide the address

   of a variable to store the lock information and the name or the

   process.  */

static gpg_error_t

lock_spawning (lock_spawn_t *lock, const char *homedir, const char *name,

               int verbose)

{

  char *fname;

  (void)verbose;

  *lock = NULL;

  fname = make_absfilename_try

    (homedir,

     !strcmp (name, "agent")?   "gnupg_spawn_agent_sentinel":

     !strcmp (name, "dirmngr")? "gnupg_spawn_dirmngr_sentinel":

     !strcmp (name, "keyboxd")? "gnupg_spawn_keyboxd_sentinel":

     /*                    */   "gnupg_spawn_unknown_sentinel",

     NULL);

  if (!fname)

    return gpg_error_from_syserror ();

  *lock = dotlock_create (fname, 0);

  xfree (fname);

  if (!*lock)

    return gpg_error_from_syserror ();

  /* FIXME: We should use a timeout of 5000 here - however

     make_dotlock does not yet support values other than -1 and 0.  */

  if (dotlock_take (*lock, -1))

    return gpg_error_from_syserror ();

  return 0;

}

/* Unlock the spawning process.  */

static void

unlock_spawning (lock_spawn_t *lock, const char *name)

{

  if (*lock)

    {

      (void)name;

      dotlock_destroy (*lock);

      *lock = NULL;

    }

}

/* Helper to start a service.  SECS gives the number of seconds to

 * wait.  SOCKNAME is the name of the socket to connect.  VERBOSE is

 * the usual verbose flag.  CTX is the assuan context.  CONNECT_FLAGS

 * are the assuan connect flags.  DID_SUCCESS_MSG will be set to 1 if

 * a success messages has been printed.

 */

static gpg_error_t

wait_for_sock (int secs, int module_name_id, const char *sockname,

               unsigned int connect_flags,

               int verbose, assuan_context_t ctx, int *did_success_msg)

{

  gpg_error_t err = 0;

  int target_us = secs * 1000000;

  int elapsed_us = 0;

  /*

   * 977us * 1024 = just a little more than 1s.

   * so we will double this timeout 10 times in the first

   * second, and then switch over to 1s checkins.

   */

  int next_sleep_us = 977;

  int lastalert = secs+1;

  int secsleft;

  while (elapsed_us < target_us)

    {

      if (verbose)

        {

          secsleft = (target_us - elapsed_us + 999999)/1000000;

          /* log_clock ("left=%d last=%d targ=%d elap=%d next=%d\n", */

          /*            secsleft, lastalert, target_us, elapsed_us, */

          /*            next_sleep_us); */

          if (secsleft < lastalert)

            {

              log_info (module_name_id == GNUPG_MODULE_NAME_DIRMNGR?

                        _("waiting for the dirmngr to come up ... (%ds)\n"):

                        module_name_id == GNUPG_MODULE_NAME_KEYBOXD?

                        _("waiting for the keyboxd to come up ... (%ds)\n"):

                        _("waiting for the agent to come up ... (%ds)\n"),

                        secsleft);

              lastalert = secsleft;

            }

        }

      gnupg_usleep (next_sleep_us);

      elapsed_us += next_sleep_us;

      err = assuan_socket_connect (ctx, sockname, 0, connect_flags);

      if (!err)

        {

          if (verbose)

            {

              log_info (module_name_id == GNUPG_MODULE_NAME_DIRMNGR?

                        _("connection to the dirmngr established\n"):

                        module_name_id == GNUPG_MODULE_NAME_KEYBOXD?

                        _("connection to the keyboxd established\n"):

                        _("connection to the agent established\n"));

              *did_success_msg = 1;

            }

          break;

        }

      next_sleep_us *= 2;

      if (next_sleep_us > 1000000)

        next_sleep_us = 1000000;

    }

  return err;

}

/* Try to connect to a new service via socket or start it if it is not

 * running and AUTOSTART is set.  Handle the server's initial

 * greeting.  Returns a new assuan context at R_CTX or an error code.

 * MODULE_NAME_ID is one of:

 *     GNUPG_MODULE_NAME_AGENT

 *     GNUPG_MODULE_NAME_DIRMNGR

 */

static gpg_error_t

start_new_service (assuan_context_t *r_ctx,

                   int module_name_id,

                   gpg_err_source_t errsource,

                   const char *program_name,

                   const char *opt_lc_ctype,

                   const char *opt_lc_messages,

                   session_env_t session_env,

                   unsigned int flags,

                   int verbose, int debug,

                   gpg_error_t (*status_cb)(ctrl_t, int, ...),

                   ctrl_t status_cb_arg)

{

  gpg_error_t err;

  assuan_context_t ctx;

  int did_success_msg = 0;

  char *sockname;

  const char *printed_name;

  const char *lock_name;

  const char *status_start_line;

  int no_service_err;

  int seconds_to_wait;

  unsigned int connect_flags = 0;

  const char *argv[6];

  *r_ctx = NULL;

  err = assuan_new (&ctx);

  if (err)

    {

      log_error ("error allocating assuan context: %s\n", gpg_strerror (err));

      return err;

    }

  switch (module_name_id)

    {

    case GNUPG_MODULE_NAME_AGENT:

      sockname = make_filename (gnupg_socketdir (), GPG_AGENT_SOCK_NAME, NULL);

      lock_name = "agent";

      printed_name = "gpg-agent";

      status_start_line = "starting_agent ? 0 0";

      no_service_err = GPG_ERR_NO_AGENT;

      seconds_to_wait = SECS_TO_WAIT_FOR_AGENT;

      break;

    case GNUPG_MODULE_NAME_DIRMNGR:

      sockname = make_filename (gnupg_socketdir (), DIRMNGR_SOCK_NAME, NULL);

      lock_name = "dirmngr";

      printed_name = "dirmngr";

      status_start_line = "starting_dirmngr ? 0 0";

      no_service_err = GPG_ERR_NO_DIRMNGR;

      seconds_to_wait = SECS_TO_WAIT_FOR_DIRMNGR;

      break;

    case GNUPG_MODULE_NAME_KEYBOXD:

      sockname = make_filename (gnupg_socketdir (), KEYBOXD_SOCK_NAME, NULL);

      lock_name = "keyboxd";

      printed_name = "keyboxd";

      status_start_line = "starting_keyboxd ? 0 0";

      no_service_err = GPG_ERR_NO_KEYBOXD;

      seconds_to_wait = SECS_TO_WAIT_FOR_KEYBOXD;

      connect_flags |= ASSUAN_SOCKET_CONNECT_FDPASSING;

      break;

    default:

      err = gpg_error (GPG_ERR_INV_ARG);

      assuan_release (ctx);

      return err;

    }

  err = assuan_socket_connect (ctx, sockname, 0, connect_flags);

  if (err && (flags & ASSHELP_FLAG_AUTOSTART))

    {

      char *abs_homedir;

      lock_spawn_t lock;

      char *program = NULL;

      const char *program_arg = NULL;

      char *p;

      const char *s;

      int i;

      /* With no success start a new server.  */

      if (!program_name || !*program_name)

        program_name = gnupg_module_name (module_name_id);

      else if ((s=strchr (program_name, '|')) && s[1] == '-' && s[2]=='-')

        {

          /* Hack to insert an additional option on the command line.  */

          program = xtrystrdup (program_name);

          if (!program)

            {

              gpg_error_t tmperr = gpg_err_make (errsource,

                                                 gpg_err_code_from_syserror ());

              xfree (sockname);

              assuan_release (ctx);

              return tmperr;

            }

          p = strchr (program, '|');

          *p++ = 0;

          program_arg = p;

        }

      if (verbose)

        log_info (_("no running %s - starting '%s'\n"),

                  printed_name, program_name);

      if (status_cb)

        status_cb (status_cb_arg, STATUS_PROGRESS, status_start_line, NULL);

      /* We better pass an absolute home directory to the service just

       * in case the service does not convert the passed name to an

       * absolute one (which it should do).  */

      abs_homedir = make_absfilename_try (gnupg_homedir (), NULL);

      if (!abs_homedir)

        {

          gpg_error_t tmperr = gpg_err_make (errsource,

                                             gpg_err_code_from_syserror ());

          log_error ("error building filename: %s\n", gpg_strerror (tmperr));

          xfree (sockname);

          assuan_release (ctx);

          xfree (program);

          return tmperr;

        }

      if (fflush (NULL))

        {

          gpg_error_t tmperr = gpg_err_make (errsource,

                                             gpg_err_code_from_syserror ());

          log_error ("error flushing pending output: %s\n", strerror (errno));

          xfree (sockname);

          assuan_release (ctx);

          xfree (abs_homedir);

          xfree (program);

          return tmperr;

        }

      i = 0;

      argv[i++] = "--homedir";

      argv[i++] = abs_homedir;

      if (program_arg)

        argv[i++] = program_arg;

      argv[i++] = "--daemon";

      argv[i++] = NULL;

      if (!(err = lock_spawning (&lock, gnupg_homedir (), lock_name, verbose))

          && assuan_socket_connect (ctx, sockname, 0, connect_flags))

        {

#ifdef HAVE_W32_SYSTEM

          gpgrt_process_t proc;

          /* On Windows we remove the socketname before creating it.

           * This is so that we can wait for a client which is

           * currently trying to connect.  The 10000 will make the

           * remove function wait up to 10 seconds for sharing

           * violation to go away.  */

          gnupg_remove_ext (sockname, 10000);

          err = gpgrt_process_spawn (program? program : program_name, argv,

                                     (GPGRT_PROCESS_DETACHED

                                      |GPGRT_PROCESS_STDIO_NUL

                                      |GPGRT_PROCESS_STDOUT_PIPE

                                      |GPGRT_PROCESS_STDERR_KEEP),

                                     NULL, &proc);

          if (!err)

            {

              int pipe_in;

              err = gpgrt_process_get_fds (proc, 0, NULL, &pipe_in, NULL);

              if (!err)

                {

                  char buf[256];

                  int r;

                  /* We wait until the child process says it's ready

                     to serve, by reading from the pipe.  */

                  r = read (pipe_in, buf, sizeof buf);

                  close (pipe_in);

                  if (r < 0)

                    {

                      if (verbose)

                        log_info ("read from child process failed: %s\n",

                                  strerror (errno));

                      /*

                       * Go ahead, ignoring the read error, so that

                       * we can still support older Windows (< Vista).

                       *

                       * In future, we should return error with

                       * GPG_ERR_SERVER_FAILED here.

                       */

                    }

                }

              gpgrt_process_release (proc);

            }

#else /*!W32*/

          err = gpgrt_process_spawn (program? program : program_name, argv,

                                     0, NULL, NULL);

#endif /*!W32*/

          if (err)

            log_error ("failed to start %s '%s': %s\n",

                       printed_name, program? program : program_name,

                       gpg_strerror (err));

          else

            err = wait_for_sock (seconds_to_wait, module_name_id,

                                 sockname, connect_flags,

                                 verbose, ctx, &did_success_msg);

        }

      unlock_spawning (&lock, lock_name);

      xfree (abs_homedir);

      xfree (program);

    }

  xfree (sockname);

  if (err)

    {

      if ((flags & ASSHELP_FLAG_AUTOSTART)

          || gpg_err_code (err) != GPG_ERR_ASS_CONNECT_FAILED)

        log_error ("can't connect to the %s: %s\n",

                   printed_name, gpg_strerror (err));

      assuan_release (ctx);

      return gpg_err_make (errsource, no_service_err);

    }

  if (debug && !did_success_msg)

    log_debug ("connection to the %s established\n", printed_name);

  if (module_name_id == GNUPG_MODULE_NAME_AGENT)

    err = assuan_transact (ctx, "RESET",

                           NULL, NULL, NULL, NULL, NULL, NULL);

  if (!err

      && module_name_id == GNUPG_MODULE_NAME_AGENT)

    {

      err = send_pinentry_environment (ctx, errsource,

                                       opt_lc_ctype, opt_lc_messages,

                                       session_env);

      if (gpg_err_code (err) == GPG_ERR_FORBIDDEN

          && gpg_err_source (err) == GPG_ERR_SOURCE_GPGAGENT)

        {

          /* Check whether the agent is in restricted mode.  */

          if (!assuan_transact (ctx, "GETINFO restricted",

                                NULL, NULL, NULL, NULL, NULL, NULL))

            {

              if (verbose)

                log_info (_("connection to the agent is in restricted mode\n"));

              err = 0;

            }

        }

    }

  if (err)

    {

      assuan_release (ctx);

      return err;

    }

  *r_ctx = ctx;

  return 0;

}

/* Try to connect to the agent or start a new one.  */

gpg_error_t

start_new_gpg_agent (assuan_context_t *r_ctx,

                     gpg_err_source_t errsource,

                     const char *agent_program,

                     const char *opt_lc_ctype,

                     const char *opt_lc_messages,

                     session_env_t session_env,

                     unsigned int flags,

                     int verbose, int debug,

                     gpg_error_t (*status_cb)(ctrl_t, int, ...),

                     ctrl_t status_cb_arg)

{

  return start_new_service (r_ctx, GNUPG_MODULE_NAME_AGENT,

                            errsource, agent_program,

                            opt_lc_ctype, opt_lc_messages, session_env,

                            flags, verbose, debug,

                            status_cb, status_cb_arg);

}

/* Try to connect to the dirmngr via a socket.  On platforms

   supporting it, start it up if needed and if ASSHELP_FLAG_AUTOSTART is set.

   Returns a new assuan context at R_CTX or an error code. */

gpg_error_t

start_new_keyboxd (assuan_context_t *r_ctx,

                   gpg_err_source_t errsource,

                   const char *keyboxd_program,

                   unsigned int flags,

                   int verbose, int debug,

                   gpg_error_t (*status_cb)(ctrl_t, int, ...),

                   ctrl_t status_cb_arg)

{

  return start_new_service (r_ctx, GNUPG_MODULE_NAME_KEYBOXD,

                            errsource, keyboxd_program,

                            NULL, NULL, NULL,

                            flags, verbose, debug,

                            status_cb, status_cb_arg);

}

/* Try to connect to the dirmngr via a socket.  On platforms

   supporting it, start it up if needed and if ASSHELP_FLAG_AUTOSTART is set.

   Returns a new assuan context at R_CTX or an error code. */

gpg_error_t

start_new_dirmngr (assuan_context_t *r_ctx,

                   gpg_err_source_t errsource,

                   const char *dirmngr_program,

                   unsigned int flags,

                   int verbose, int debug,

                   gpg_error_t (*status_cb)(ctrl_t, int, ...),

                   ctrl_t status_cb_arg)

{

#ifndef USE_DIRMNGR_AUTO_START

  flags &= ~ASSHELP_FLAG_AUTOSTART;  /* Clear flag.  */

#endif

  return start_new_service (r_ctx, GNUPG_MODULE_NAME_DIRMNGR,

                            errsource, dirmngr_program,

                            NULL, NULL, NULL,

                            flags, verbose, debug,

                            status_cb, status_cb_arg);

}

/* Return the version of a server using "GETINFO version".  On success

   0 is returned and R_VERSION receives a malloced string with the

   version which must be freed by the caller.  On error NULL is stored

   at R_VERSION and an error code returned.  Mode is in general 0 but

   certain values may be used to modify the used version command:

      MODE == 0 = Use "GETINFO version"

      MODE == 2 - Use "SCD GETINFO version"

 */

gpg_error_t

get_assuan_server_version (assuan_context_t ctx, int mode, char **r_version)

{

  gpg_error_t err;

  membuf_t data;

  init_membuf (&data, 64);

  err = assuan_transact (ctx,

                         mode == 2? "SCD GETINFO version"

                         /**/     : "GETINFO version",

                         put_membuf_cb, &data,

                         NULL, NULL, NULL, NULL);

  if (err)

    {

      xfree (get_membuf (&data, NULL));

      *r_version = NULL;

    }

  else

    {

      put_membuf (&data, "", 1);

      *r_version = get_membuf (&data, NULL);

      if (!*r_version)

        err = gpg_error_from_syserror ();

    }

  return err;

}

/* Print a warning if the server's version number is less than our

 * version number.  Returns an error code on a connection problem.

 * CTX is the Assuan context, SERVERNAME is the name of the server,

 * STATUS_FUNC and STATUS_FUNC_DATA is a callback to emit status

 * messages.  If PRINT_HINTS is set additional hints are printed.  For

 * MODE see get_assuan_server_version.  */

gpg_error_t

warn_server_version_mismatch (assuan_context_t ctx,

                              const char *servername, int mode,

                              gpg_error_t (*status_func)(ctrl_t ctrl,

                                                         int status_no,

                                                         ...),

                              void *status_func_ctrl,

                              int print_hints)

{

  gpg_error_t err;

  char *serverversion;

  const char *myversion = gpgrt_strusage (13);

  err = get_assuan_server_version (ctx, mode, &serverversion);

  if (err)

    log_log (gpg_err_code (err) == GPG_ERR_NOT_SUPPORTED?

             GPGRT_LOGLVL_INFO : GPGRT_LOGLVL_ERROR,

             _("error getting version from '%s': %s\n"),

             servername, gpg_strerror (err));

  else if (compare_version_strings (serverversion, myversion) < 0)

    {

      char *warn;

      warn = xtryasprintf (_("server '%s' is older than us (%s < %s)"),

                           servername, serverversion, myversion);

      if (!warn)

        err = gpg_error_from_syserror ();

      else

        {

          log_info (_("WARNING: %s\n"), warn);

          if (print_hints)

            {

              log_info (_("Note: Outdated servers may lack important"

                          " security fixes.\n"));

              log_info (_("Note: Use the command \"%s\" to restart them.\n"),

                        "gpgconf --kill all");

            }

          if (status_func)

            status_func (status_func_ctrl, STATUS_WARNING,

                         "server_version_mismatch 0", warn, NULL);

          xfree (warn);

        }

    }

  xfree (serverversion);

  return err;

}

#ifdef HAVE_W32_SYSTEM

#include <fcntl.h>

/*

 * At the start of service (gpg-agent/dirmngr/keyboxd), after the

 * preparation of socket, send "OK" (or "ERR 1") to the frontend

 * (gpg/gpgsm).

 */

void

w32_ack_to_frontend (void)

{

  int null_fd = open ("NUL", O_RDWR);

  /* For the case of older Windows (< Vista), stdin/stdout/stder is

   * invalid handle and write to stdout may fail.  We ignore this

   * error.  */

  if (null_fd < 0)

    {

      perror ("open failed");

      /* Reply "General Error".  */

      write (1, "ERR 1\n", 6);

    }

  else

    {

      /* Reply, it's OK (because it's ready to serve).  */

      write (1, "OK\n", 3);

      if (dup2 (null_fd, 1) < 0)

        perror ("dup2 failed");

      dup2 (null_fd, 2);

      close (null_fd);

    }

}

#endif