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/*
This file is part of GNUnet.
Copyright (C) 2010, 2011, 2012 Christian Grothoff
Copyright (C) 2019 GNUnet e.V.
GNUnet is free software: you can redistribute it and/or modify it
under the terms of the GNU Affero General Public License as published
by the Free Software Foundation, either version 3 of the License,
or (at your option) any later version.
GNUnet 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
Affero General Public License for more details.
You should have received a copy of the GNU Affero General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
SPDX-License-Identifier: AGPL3.0-or-later
*/
#include "platform.h"
//
// FIXME: These functions are copied from dns/gnunet-helper-dns.c,
// move them into a common library. Or think about implementing a even
// more elaborate version.
//
/**
* Open '/dev/null' and make the result the given
* file descriptor.
*
* @param target_fd desired FD to point to /dev/null
* @param flags open flags (O_RDONLY, O_WRONLY)
*/
static void
open_dev_null (int target_fd,
int flags)
{
int fd;
fd = open ("/dev/null", flags);
if (-1 == fd)
abort ();
if (fd == target_fd)
return;
if (-1 == dup2 (fd, target_fd))
{
(void) close (fd);
abort ();
}
(void) close (fd);
}
/**
* Run the given command and wait for it to complete.
*
* @param file name of the binary to run
* @param cmd command line arguments (as given to 'execv')
* @return 0 on success, 1 on any error
*/
static int
fork_and_exec (const char *file,
char *const cmd[])
{
int status;
pid_t pid;
pid_t ret;
pid = fork ();
if (-1 == pid)
{
fprintf (stderr,
"fork failed: %s\n",
strerror (errno));
return 1;
}
if (0 == pid)
{
/* we are the child process */
/* close stdin/stdout to not cause interference
with the helper's main protocol! */
(void) close (0);
open_dev_null (0, O_RDONLY);
(void) close (1);
open_dev_null (1, O_WRONLY);
(void) execv (file, cmd);
/* can only get here on error */
fprintf (stderr,
"exec `%s' failed: %s\n",
file,
strerror (errno));
_exit (1);
}
/* keep running waitpid as long as the only error we get is 'EINTR' */
while ( (-1 == (ret = waitpid (pid, &status, 0))) &&
(errno == EINTR) );
if (-1 == ret)
{
fprintf (stderr,
"waitpid failed: %s\n",
strerror (errno));
return 1;
}
if (! (WIFEXITED (status) && (0 == WEXITSTATUS (status))))
return 1;
/* child process completed and returned success, we're happy */
return 0;
}
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