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gnupg/common/asshelp.c

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/* asshelp.c - Helper functions for Assuan
* Copyright (C) 2002, 2004, 2007, 2009, 2010 Free Software Foundation, Inc.
*
* 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 <string.h>
#include <unistd.h>
#include <errno.h>
#ifdef HAVE_LOCALE_H
#include <locale.h>
#endif
#define JNLIB_NEED_LOG_LOGV
#include "i18n.h"
#include "util.h"
#include "exechelp.h"
#include "sysutils.h"
#include "status.h"
#include "asshelp.h"
/* The type we use for lock_agent_spawning. */
#ifdef HAVE_W32_SYSTEM
# define lock_agent_t HANDLE
#else
# define lock_agent_t dotlock_t
#endif
/* 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))))
static int
my_libassuan_log_handler (assuan_context_t ctx, void *hook,
unsigned int cat, const char *msg)
{
unsigned int dbgval;
(void)ctx;
if (! TEST_LOG_CAT (cat))
return 0;
dbgval = hook? *(unsigned int*)hook : 0;
if (!(dbgval & 1024))
return 0; /* Assuan debugging is not enabled. */
if (msg)
log_string (JNLIB_LOG_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)
{
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));
assuan_set_log_cb (my_libassuan_log_handler, debug_var_address);
}
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 the agent spawning process. The caller needs to provide the
address of a variable to store the lock information. */
static gpg_error_t
lock_agent_spawning (lock_agent_t *lock, const char *homedir)
{
#ifdef HAVE_W32_SYSTEM
int waitrc;
(void)homedir; /* Not required. */
*lock = CreateMutex (NULL, FALSE, "GnuPG_spawn_agent_sentinel");
if (!*lock)
{
log_error ("failed to create the spawn_agent mutex: %s\n",
w32_strerror (-1));
return gpg_error (GPG_ERR_GENERAL);
}
waitrc = WaitForSingleObject (*lock, 5000);
if (waitrc == WAIT_OBJECT_0)
return 0;
if (waitrc == WAIT_TIMEOUT)
log_info ("error waiting for the spawn_agent mutex: timeout\n");
else
log_info ("error waiting for the spawn_agent mutex: "
"(code=%d) %s\n", waitrc, w32_strerror (-1));
return gpg_error (GPG_ERR_GENERAL);
#else /*!HAVE_W32_SYSTEM*/
char *fname;
*lock = NULL;
fname = make_filename (homedir, "gnupg_spawn_agent_sentinel", NULL);
if (!fname)
return gpg_error_from_syserror ();
*lock = create_dotlock (fname);
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 (make_dotlock (*lock, -1))
return gpg_error_from_syserror ();
return 0;
#endif /*!HAVE_W32_SYSTEM*/
}
/* Unlock the spawning process. */
static void
unlock_agent_spawning (lock_agent_t *lock)
{
if (*lock)
{
#ifdef HAVE_W32_SYSTEM
if (!ReleaseMutex (*lock))
log_error ("failed to release the spawn_agent mutex: %s\n",
w32_strerror (-1));
CloseHandle (*lock);
#else /*!HAVE_W32_SYSTEM*/
destroy_dotlock (*lock);
#endif /*!HAVE_W32_SYSTEM*/
*lock = NULL;
}
}
/* Try to connect to the agent via socket or fork it off and work by
pipes. Handle the server's initial greeting. Returns a new assuan
context at R_CTX or an error code. */
gpg_error_t
start_new_gpg_agent (assuan_context_t *r_ctx,
gpg_err_source_t errsource,
const char *homedir,
const char *agent_program,
const char *opt_lc_ctype,
const char *opt_lc_messages,
session_env_t session_env,
int verbose, int debug,
gpg_error_t (*status_cb)(ctrl_t, int, ...),
ctrl_t status_cb_arg)
{
/* If we ever failed to connect via a socket we will force the use
of the pipe based server for the lifetime of the process. */
static int force_pipe_server = 0;
gpg_error_t err = 0;
char *infostr, *p;
assuan_context_t ctx;
*r_ctx = NULL;
err = assuan_new (&ctx);
if (err)
{
log_error ("error allocating assuan context: %s\n", gpg_strerror (err));
return err;
}
restart:
infostr = force_pipe_server? NULL : getenv ("GPG_AGENT_INFO");
if (!infostr || !*infostr)
{
char *sockname;
const char *argv[3];
pid_t pid;
int excode;
/* First check whether we can connect at the standard
socket. */
sockname = make_filename (homedir, "S.gpg-agent", NULL);
err = assuan_socket_connect (ctx, sockname, 0, 0);
if (err)
{
/* With no success start a new server. */
if (verbose)
log_info (_("no running gpg-agent - starting one\n"));
if (status_cb)
status_cb (status_cb_arg, STATUS_PROGRESS,
"starting_agent ? 0 0", NULL);
if (fflush (NULL))
{
gpg_error_t tmperr = gpg_error (gpg_err_code_from_errno (errno));
log_error ("error flushing pending output: %s\n",
strerror (errno));
xfree (sockname);
assuan_release (ctx);
return tmperr;
}
if (!agent_program || !*agent_program)
agent_program = gnupg_module_name (GNUPG_MODULE_NAME_AGENT);
argv[0] = "--use-standard-socket-p";
argv[1] = NULL;
err = gnupg_spawn_process_fd (agent_program, argv, -1, -1, -1, &pid);
if (err)
log_debug ("starting `%s' for testing failed: %s\n",
agent_program, gpg_strerror (err));
else if ((err = gnupg_wait_process (agent_program, pid, 0, &excode)))
{
if (excode == -1)
log_debug ("running `%s' for testing failed: %s\n",
agent_program, gpg_strerror (err));
}
gnupg_release_process (pid);
if (!err && !excode)
{
/* If the agent has been configured for use with a
standard socket, an environment variable is not
required and thus we we can savely start the agent
here. */
lock_agent_t lock;
argv[0] = "--daemon";
argv[1] = "--use-standard-socket";
argv[2] = NULL;
if (!(err = lock_agent_spawning (&lock, homedir))
&& assuan_socket_connect (ctx, sockname, 0, 0))
{
err = gnupg_spawn_process_detached (agent_program, argv,NULL);
if (err)
log_error ("failed to start agent `%s': %s\n",
agent_program, gpg_strerror (err));
else
{
int i;
if (verbose)
log_info (_("waiting %d seconds for the agent "
"to come up\n"), 5);
for (i=0; i < 5; i++)
{
gnupg_sleep (1);
err = assuan_socket_connect (ctx, sockname, 0, 0);
if (!err)
break;
}
}
}
unlock_agent_spawning (&lock);
}
else
{
/* If using the standard socket is not the default we
start the agent as a pipe server which gives us most
of the required features except for passphrase
caching etc. */
const char *pgmname;
int no_close_list[3];
int i;
if ( !(pgmname = strrchr (agent_program, '/')))
pgmname = agent_program;
else
pgmname++;
argv[0] = pgmname;
argv[1] = "--server";
argv[2] = NULL;
i=0;
if (log_get_fd () != -1)
no_close_list[i++] = assuan_fd_from_posix_fd (log_get_fd ());
no_close_list[i++] = assuan_fd_from_posix_fd (fileno (stderr));
no_close_list[i] = -1;
/* Connect to the agent and perform initial handshaking. */
err = assuan_pipe_connect (ctx, agent_program, argv,
no_close_list, NULL, NULL, 0);
}
}
xfree (sockname);
}
else
{
int prot;
int pid;
infostr = xstrdup (infostr);
if ( !(p = strchr (infostr, PATHSEP_C)) || p == infostr)
{
log_error (_("malformed GPG_AGENT_INFO environment variable\n"));
xfree (infostr);
force_pipe_server = 1;
goto restart;
}
*p++ = 0;
pid = atoi (p);
while (*p && *p != PATHSEP_C)
p++;
prot = *p? atoi (p+1) : 0;
if (prot != 1)
{
log_error (_("gpg-agent protocol version %d is not supported\n"),
prot);
xfree (infostr);
force_pipe_server = 1;
goto restart;
}
err = assuan_socket_connect (ctx, infostr, pid, 0);
xfree (infostr);
if (gpg_err_code (err) == GPG_ERR_ASS_CONNECT_FAILED)
{
log_info (_("can't connect to the agent - trying fall back\n"));
force_pipe_server = 1;
goto restart;
}
}
if (err)
{
log_error ("can't connect to the agent: %s\n", gpg_strerror (err));
assuan_release (ctx);
return gpg_error (GPG_ERR_NO_AGENT);
}
if (debug)
log_debug ("connection to agent established\n");
err = assuan_transact (ctx, "RESET",
NULL, NULL, NULL, NULL, NULL, NULL);
if (!err)
err = send_pinentry_environment (ctx, errsource,
opt_lc_ctype, opt_lc_messages,
session_env);
if (err)
{
assuan_release (ctx);
return err;
}
*r_ctx = ctx;
return 0;
}
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