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/* Copyright (C) 1994-2020 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#include <errno.h>
#include <stddef.h>
#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <sysdep.h>
#include <sys/syscall.h>
#include <kernel-features.h>
#include <fd_to_filename.h>
#include <not-cancel.h>
/* Execute the file FD refers to, overlaying the running program image.
ARGV and ENVP are passed to the new program, as for `execve'. */
int
execveat (int dirfd, const char *path, char *const argv[], char *const envp[],
int flags)
{
/* Avoid implicit array coercion in syscall macros. */
INLINE_SYSCALL_CALL (execveat, dirfd, path, &argv[0], &envp[0], flags);
#ifndef __ASSUME_EXECVEAT
if (errno != ENOSYS)
return -1;
if ((flags & ~(AT_EMPTY_PATH | AT_SYMLINK_NOFOLLOW)) != 0)
return EINVAL;
int fd;
if (path[0] == '\0' && (flags & AT_EMPTY_PATH) && dirfd >= 0)
fd = dirfd;
else
{
int oflags = O_CLOEXEC;
if (flags & AT_SYMLINK_NOFOLLOW)
oflags |= O_NOFOLLOW;
fd = openat (dirfd, path, oflags);
}
if (fd < 0)
return -1;
struct fd_to_filename fdfilename;
const char *gfilename = __fd_to_filename (fd, &fdfilename);
/* We do not need the return value. */
__execve (gfilename, argv, envp);
int save = errno;
/* We come here only if the 'execve' call fails. Determine whether
/proc is mounted. If not we return ENOSYS. */
struct stat st;
if (stat ("/proc/self/fd", &st) != 0 && errno == ENOENT)
save = ENOSYS;
if (fd != dirfd)
__close_nocancel (fd);
__set_errno (save);
#endif
return -1;
}
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