mirror of
git://git.gnupg.org/gnupg.git
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608 lines
14 KiB
C
608 lines
14 KiB
C
/* exechelp.c - Fork and exec helpers for POSIX
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* Copyright (C) 2004, 2007, 2008, 2009,
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* 2010 Free Software Foundation, Inc.
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*
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* This file is part of GnuPG.
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*
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* GnuPG is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 3 of the License, or
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* (at your option) any later version.
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*
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* GnuPG is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, see <http://www.gnu.org/licenses/>.
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*/
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#include <config.h>
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#if defined(HAVE_W32_SYSTEM) || defined (HAVE_W32CE_SYSTEM)
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#error This code is only used on POSIX
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#endif
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <errno.h>
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#include <assert.h>
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#ifdef HAVE_SIGNAL_H
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# include <signal.h>
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#endif
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#include <unistd.h>
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#include <fcntl.h>
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#ifdef WITHOUT_NPTH /* Give the Makefile a chance to build without Pth. */
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#undef HAVE_NPTH
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#undef USE_NPTH
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#endif
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#ifdef USE_NPTH
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#include <npth.h>
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#endif
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#include <sys/wait.h>
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#ifdef HAVE_GETRLIMIT
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#include <sys/time.h>
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#include <sys/resource.h>
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#endif /*HAVE_GETRLIMIT*/
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#ifdef HAVE_STAT
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# include <sys/stat.h>
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#endif
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#include "util.h"
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#include "i18n.h"
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#include "sysutils.h"
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#include "exechelp.h"
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/* We have the usual problem here: Some modules are linked against pth
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and some are not. However we want to use pth_fork and pth_waitpid
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here. Using a weak symbol works but is not portable - we should
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provide a an explicit dummy pth module instead of using the
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pragma. */
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#pragma weak pth_fork
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#pragma weak pth_waitpid
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/* Return the maximum number of currently allowed open file
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descriptors. Only useful on POSIX systems but returns a value on
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other systems too. */
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int
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get_max_fds (void)
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{
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int max_fds = -1;
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#ifdef HAVE_GETRLIMIT
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struct rlimit rl;
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# ifdef RLIMIT_NOFILE
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if (!getrlimit (RLIMIT_NOFILE, &rl))
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max_fds = rl.rlim_max;
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# endif
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# ifdef RLIMIT_OFILE
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if (max_fds == -1 && !getrlimit (RLIMIT_OFILE, &rl))
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max_fds = rl.rlim_max;
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# endif
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#endif /*HAVE_GETRLIMIT*/
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#ifdef _SC_OPEN_MAX
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if (max_fds == -1)
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{
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long int scres = sysconf (_SC_OPEN_MAX);
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if (scres >= 0)
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max_fds = scres;
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}
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#endif
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#ifdef _POSIX_OPEN_MAX
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if (max_fds == -1)
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max_fds = _POSIX_OPEN_MAX;
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#endif
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#ifdef OPEN_MAX
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if (max_fds == -1)
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max_fds = OPEN_MAX;
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#endif
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if (max_fds == -1)
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max_fds = 256; /* Arbitrary limit. */
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return max_fds;
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}
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/* Close all file descriptors starting with descriptor FIRST. If
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EXCEPT is not NULL, it is expected to be a list of file descriptors
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which shall not be closed. This list shall be sorted in ascending
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order with the end marked by -1. */
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void
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close_all_fds (int first, int *except)
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{
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int max_fd = get_max_fds ();
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int fd, i, except_start;
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if (except)
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{
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except_start = 0;
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for (fd=first; fd < max_fd; fd++)
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{
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for (i=except_start; except[i] != -1; i++)
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{
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if (except[i] == fd)
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{
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/* If we found the descriptor in the exception list
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we can start the next compare run at the next
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index because the exception list is ordered. */
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except_start = i + 1;
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break;
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}
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}
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if (except[i] == -1)
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close (fd);
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}
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}
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else
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{
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for (fd=first; fd < max_fd; fd++)
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close (fd);
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}
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gpg_err_set_errno (0);
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}
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/* Returns an array with all currently open file descriptors. The end
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of the array is marked by -1. The caller needs to release this
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array using the *standard free* and not with xfree. This allow the
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use of this fucntion right at startup even before libgcrypt has
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been initialized. Returns NULL on error and sets ERRNO
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accordingly. */
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int *
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get_all_open_fds (void)
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{
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int *array;
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size_t narray;
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int fd, max_fd, idx;
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#ifndef HAVE_STAT
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array = calloc (1, sizeof *array);
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if (array)
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array[0] = -1;
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#else /*HAVE_STAT*/
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struct stat statbuf;
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max_fd = get_max_fds ();
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narray = 32; /* If you change this change also t-exechelp.c. */
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array = calloc (narray, sizeof *array);
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if (!array)
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return NULL;
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/* Note: The list we return is ordered. */
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for (idx=0, fd=0; fd < max_fd; fd++)
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if (!(fstat (fd, &statbuf) == -1 && errno == EBADF))
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{
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if (idx+1 >= narray)
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{
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int *tmp;
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narray += (narray < 256)? 32:256;
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tmp = realloc (array, narray * sizeof *array);
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if (!tmp)
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{
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free (array);
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return NULL;
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}
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array = tmp;
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}
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array[idx++] = fd;
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}
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array[idx] = -1;
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#endif /*HAVE_STAT*/
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return array;
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}
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/* The exec core used right after the fork. This will never return. */
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static void
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do_exec (const char *pgmname, const char *argv[],
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int fd_in, int fd_out, int fd_err,
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void (*preexec)(void) )
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{
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char **arg_list;
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int i, j;
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int fds[3];
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fds[0] = fd_in;
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fds[1] = fd_out;
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fds[2] = fd_err;
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/* Create the command line argument array. */
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i = 0;
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if (argv)
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while (argv[i])
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i++;
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arg_list = xcalloc (i+2, sizeof *arg_list);
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arg_list[0] = strrchr (pgmname, '/');
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if (arg_list[0])
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arg_list[0]++;
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else
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arg_list[0] = xstrdup (pgmname);
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if (argv)
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for (i=0,j=1; argv[i]; i++, j++)
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arg_list[j] = (char*)argv[i];
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/* Assign /dev/null to unused FDs. */
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for (i=0; i <= 2; i++)
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{
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if (fds[i] == -1 )
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{
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fds[i] = open ("/dev/null", i? O_WRONLY : O_RDONLY);
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if (fds[i] == -1)
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log_fatal ("failed to open `%s': %s\n",
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"/dev/null", strerror (errno));
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}
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}
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/* Connect the standard files. */
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for (i=0; i <= 2; i++)
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{
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if (fds[i] != i && dup2 (fds[i], i) == -1)
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log_fatal ("dup2 std%s failed: %s\n",
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i==0?"in":i==1?"out":"err", strerror (errno));
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}
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/* Close all other files. */
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close_all_fds (3, NULL);
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if (preexec)
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preexec ();
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execv (pgmname, arg_list);
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/* No way to print anything, as we have closed all streams. */
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_exit (127);
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}
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static gpg_error_t
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do_create_pipe (int filedes[2])
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{
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gpg_error_t err = 0;
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if (pipe (filedes) == -1)
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{
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err = gpg_error_from_syserror ();
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filedes[0] = filedes[1] = -1;
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}
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return err;
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}
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/* Portable function to create a pipe. Under Windows the write end is
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inheritable. */
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gpg_error_t
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gnupg_create_inbound_pipe (int filedes[2])
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{
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return do_create_pipe (filedes);
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}
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/* Portable function to create a pipe. Under Windows the read end is
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inheritable. */
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gpg_error_t
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gnupg_create_outbound_pipe (int filedes[2])
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{
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return do_create_pipe (filedes);
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}
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static gpg_error_t
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create_pipe_and_estream (int filedes[2], estream_t *r_fp,
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gpg_err_source_t errsource)
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{
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gpg_error_t err;
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if (pipe (filedes) == -1)
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{
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err = gpg_err_make (errsource, gpg_err_code_from_syserror ());
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log_error (_("error creating a pipe: %s\n"), gpg_strerror (err));
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filedes[0] = filedes[1] = -1;
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*r_fp = NULL;
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return err;
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}
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*r_fp = es_fdopen (filedes[0], "r");
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if (!*r_fp)
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{
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err = gpg_err_make (errsource, gpg_err_code_from_syserror ());
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log_error (_("error creating a stream for a pipe: %s\n"),
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gpg_strerror (err));
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close (filedes[0]);
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close (filedes[1]);
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filedes[0] = filedes[1] = -1;
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return err;
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}
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return 0;
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}
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/* Fork and exec the PGMNAME, see exechelp.h for details. */
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gpg_error_t
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gnupg_spawn_process (const char *pgmname, const char *argv[],
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gpg_err_source_t errsource,
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void (*preexec)(void), unsigned int flags,
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estream_t infp,
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estream_t *r_outfp,
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estream_t *r_errfp,
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pid_t *pid)
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{
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gpg_error_t err;
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int infd = -1;
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int outpipe[2] = {-1, -1};
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int errpipe[2] = {-1, -1};
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estream_t outfp = NULL;
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estream_t errfp = NULL;
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(void)flags; /* Currently not used. */
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if (r_outfp)
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*r_outfp = NULL;
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if (r_errfp)
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*r_errfp = NULL;
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*pid = (pid_t)(-1); /* Always required. */
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if (infp)
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{
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es_fflush (infp);
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es_rewind (infp);
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infd = es_fileno (infp);
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if (infd == -1)
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return gpg_err_make (errsource, GPG_ERR_INV_VALUE);
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}
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if (r_outfp)
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{
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err = create_pipe_and_estream (outpipe, &outfp, errsource);
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if (err)
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return err;
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}
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if (r_errfp)
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{
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err = create_pipe_and_estream (errpipe, &errfp, errsource);
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if (err)
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{
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if (outfp)
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es_fclose (outfp);
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else if (outpipe[0] != -1)
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close (outpipe[0]);
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if (outpipe[1] != -1)
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close (outpipe[1]);
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return err;
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}
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}
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*pid = fork ();
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if (*pid == (pid_t)(-1))
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{
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err = gpg_err_make (errsource, gpg_err_code_from_syserror ());
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log_error (_("error forking process: %s\n"), gpg_strerror (err));
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if (outfp)
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es_fclose (outfp);
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else if (outpipe[0] != -1)
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close (outpipe[0]);
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if (outpipe[1] != -1)
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close (outpipe[1]);
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if (errfp)
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es_fclose (errfp);
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else if (errpipe[0] != -1)
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close (errpipe[0]);
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if (errpipe[1] != -1)
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close (errpipe[1]);
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return err;
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}
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if (!*pid)
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{
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/* This is the child. */
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gcry_control (GCRYCTL_TERM_SECMEM);
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es_fclose (outfp);
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es_fclose (errfp);
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do_exec (pgmname, argv, infd, outpipe[1], errpipe[1], preexec);
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/*NOTREACHED*/
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}
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/* This is the parent. */
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if (outpipe[1] != -1)
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close (outpipe[1]);
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if (errpipe[1] != -1)
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close (errpipe[1]);
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if (r_outfp)
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*r_outfp = outfp;
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if (r_errfp)
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*r_errfp = errfp;
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return 0;
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}
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/* Simplified version of gnupg_spawn_process. This function forks and
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then execs PGMNAME, while connecting INFD to stdin, OUTFD to stdout
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and ERRFD to stderr (any of them may be -1 to connect them to
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/dev/null). The arguments for the process are expected in the NULL
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terminated array ARGV. The program name itself should not be
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included there. Calling gnupg_wait_process is required.
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Returns 0 on success or an error code. */
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gpg_error_t
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gnupg_spawn_process_fd (const char *pgmname, const char *argv[],
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int infd, int outfd, int errfd, pid_t *pid)
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{
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gpg_error_t err;
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*pid = fork ();
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if (*pid == (pid_t)(-1))
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{
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err = gpg_error_from_syserror ();
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log_error (_("error forking process: %s\n"), strerror (errno));
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return err;
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}
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if (!*pid)
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{
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gcry_control (GCRYCTL_TERM_SECMEM);
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/* Run child. */
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do_exec (pgmname, argv, infd, outfd, errfd, NULL);
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/*NOTREACHED*/
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}
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return 0;
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}
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/* See exechelp.h for the description. */
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gpg_error_t
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gnupg_wait_process (const char *pgmname, pid_t pid, int hang, int *r_exitcode)
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{
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gpg_err_code_t ec;
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int i, status;
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if (r_exitcode)
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*r_exitcode = -1;
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if (pid == (pid_t)(-1))
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return gpg_error (GPG_ERR_INV_VALUE);
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#ifdef USE_NPTH
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i = npth_waitpid (pid, &status, hang? 0:WNOHANG);
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#else
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while ((i=waitpid (pid, &status, hang? 0:WNOHANG)) == (pid_t)(-1)
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&& errno == EINTR);
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#endif
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if (i == (pid_t)(-1))
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{
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ec = gpg_err_code_from_errno (errno);
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log_error (_("waiting for process %d to terminate failed: %s\n"),
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(int)pid, strerror (errno));
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}
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else if (!i)
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{
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ec = GPG_ERR_TIMEOUT; /* Still running. */
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}
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else if (WIFEXITED (status) && WEXITSTATUS (status) == 127)
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{
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log_error (_("error running `%s': probably not installed\n"), pgmname);
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ec = GPG_ERR_CONFIGURATION;
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}
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else if (WIFEXITED (status) && WEXITSTATUS (status))
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{
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if (!r_exitcode)
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log_error (_("error running `%s': exit status %d\n"), pgmname,
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WEXITSTATUS (status));
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else
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*r_exitcode = WEXITSTATUS (status);
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ec = GPG_ERR_GENERAL;
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}
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else if (!WIFEXITED (status))
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{
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log_error (_("error running `%s': terminated\n"), pgmname);
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ec = GPG_ERR_GENERAL;
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}
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else
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{
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if (r_exitcode)
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*r_exitcode = 0;
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ec = 0;
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}
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return gpg_err_make (GPG_ERR_SOURCE_DEFAULT, ec);
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}
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void
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gnupg_release_process (pid_t pid)
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{
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(void)pid;
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}
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/* Spawn a new process and immediately detach from it. The name of
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the program to exec is PGMNAME and its arguments are in ARGV (the
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programname is automatically passed as first argument).
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Environment strings in ENVP are set. An error is returned if
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pgmname is not executable; to make this work it is necessary to
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provide an absolute file name. All standard file descriptors are
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connected to /dev/null. */
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gpg_error_t
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gnupg_spawn_process_detached (const char *pgmname, const char *argv[],
|
|
const char *envp[] )
|
|
{
|
|
pid_t pid;
|
|
int i;
|
|
|
|
if (getuid() != geteuid())
|
|
return gpg_error (GPG_ERR_BUG);
|
|
|
|
if (access (pgmname, X_OK))
|
|
return gpg_error_from_syserror ();
|
|
|
|
pid = fork ();
|
|
if (pid == (pid_t)(-1))
|
|
{
|
|
log_error (_("error forking process: %s\n"), strerror (errno));
|
|
return gpg_error_from_syserror ();
|
|
}
|
|
if (!pid)
|
|
{
|
|
pid_t pid2;
|
|
|
|
gcry_control (GCRYCTL_TERM_SECMEM);
|
|
if (setsid() == -1 || chdir ("/"))
|
|
_exit (1);
|
|
|
|
pid2 = fork (); /* Double fork to let init take over the new child. */
|
|
if (pid2 == (pid_t)(-1))
|
|
_exit (1);
|
|
if (pid2)
|
|
_exit (0); /* Let the parent exit immediately. */
|
|
|
|
if (envp)
|
|
for (i=0; envp[i]; i++)
|
|
putenv (xstrdup (envp[i]));
|
|
|
|
do_exec (pgmname, argv, -1, -1, -1, NULL);
|
|
|
|
/*NOTREACHED*/
|
|
}
|
|
|
|
if (waitpid (pid, NULL, 0) == -1)
|
|
log_error ("waitpid failed in gnupg_spawn_process_detached: %s",
|
|
strerror (errno));
|
|
|
|
return 0;
|
|
}
|
|
|
|
|
|
/* Kill a process; that is send an appropriate signal to the process.
|
|
gnupg_wait_process must be called to actually remove the process
|
|
from the system. An invalid PID is ignored. */
|
|
void
|
|
gnupg_kill_process (pid_t pid)
|
|
{
|
|
if (pid != (pid_t)(-1))
|
|
{
|
|
kill (pid, SIGTERM);
|
|
}
|
|
}
|