1/* Copyright (C) 1994-2016 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Lesser General Public
6 License as published by the Free Software Foundation; either
7 version 2.1 of the License, or (at your option) any later version.
8
9 The GNU C Library is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 Lesser General Public License for more details.
13
14 You should have received a copy of the GNU Lesser General Public
15 License along with the GNU C Library; if not, see
16 <http://www.gnu.org/licenses/>. */
17
18#include <errno.h>
19#include <stddef.h>
20#include <stdio.h>
21#include <unistd.h>
22#include <sys/stat.h>
23
24
25/* Execute the file FD refers to, overlaying the running program image.
26 ARGV and ENVP are passed to the new program, as for `execve'. */
27int
28fexecve (int fd, char *const argv[], char *const envp[])
29{
30 if (fd < 0 || argv == NULL || envp == NULL)
31 {
32 __set_errno (EINVAL);
33 return -1;
34 }
35
36 /* We use the /proc filesystem to get the information. If it is not
37 mounted we fail. */
38 char buf[sizeof "/proc/self/fd/" + sizeof (int) * 3];
39 __snprintf (buf, sizeof (buf), "/proc/self/fd/%d", fd);
40
41 /* We do not need the return value. */
42 __execve (buf, argv, envp);
43
44 int save = errno;
45
46 /* We come here only if the 'execve' call fails. Determine whether
47 /proc is mounted. If not we return ENOSYS. */
48 struct stat st;
49 if (stat ("/proc/self/fd", &st) != 0 && errno == ENOENT)
50 save = ENOSYS;
51
52 __set_errno (save);
53
54 return -1;
55}
56