qubes-linux-utils/qrexec-lib/exec.c

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/*
* The Qubes OS Project, http://www.qubes-os.org
*
* Copyright (C) 2010 Rafal Wojtczuk <rafal@invisiblethingslab.com>
*
* This program 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 2
* of the License, or (at your option) any later version.
*
* This program 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, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
*/
#include <stdlib.h>
#include <unistd.h>
#include <stdio.h>
extern void do_exec(char *);
void fix_fds(int fdin, int fdout, int fderr)
{
int i;
for (i = 0; i < 256; i++)
if (i != fdin && i != fdout && i != fderr)
close(i);
dup2(fdin, 0);
dup2(fdout, 1);
dup2(fderr, 2);
close(fdin);
close(fdout);
if (fderr != 2)
close(fderr);
}
void do_fork_exec(char *cmdline, int *pid, int *stdin_fd, int *stdout_fd,
int *stderr_fd)
{
int inpipe[2], outpipe[2], errpipe[2];
if (pipe(inpipe) || pipe(outpipe) || (stderr_fd && pipe(errpipe))) {
perror("pipe");
exit(1);
}
switch (*pid = fork()) {
case -1:
perror("fork");
exit(-1);
case 0:
if (stderr_fd) {
fix_fds(inpipe[0], outpipe[1], errpipe[1]);
} else
fix_fds(inpipe[0], outpipe[1], 2);
do_exec(cmdline);
exit(-1);
default:;
}
close(inpipe[0]);
close(outpipe[1]);
*stdin_fd = inpipe[1];
*stdout_fd = outpipe[0];
if (stderr_fd) {
close(errpipe[1]);
*stderr_fd = errpipe[0];
}
}