OpenE2K
/
glibc
2
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

Use execveat syscall in fexecve (bug 22134) 

By using execveat we no longer depend on /proc.  The execveat syscall was
introduced in 3.19, except for a few late comers.
This commit is contained in:
Andreas Schwab 2017-09-06 17:29:29 +02:00
parent a5dcc87e77
commit 43ffc53a35
8 changed files with 142 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

18
ChangeLog
View File

@ -1,3 +1,21 @@
2017-09-19 Andreas Schwab <schwab@suse.de>
[BZ #22134]
* sysdeps/unix/sysv/linux/fexecve.c (fexecve) [__NR_execveat]: Try
execveat first.
[!__ASSUME_EXECVEAT]: Fall back to /proc if execveat is
unimplemented.
* sysdeps/unix/sysv/linux/kernel-features.h (__ASSUME_EXECVEAT)
[__LINUX_KERNEL_VERSION >= 0x031300]: Define.
* sysdeps/unix/sysv/linux/alpha/kernel-features.h
(__ASSUME_EXECVEAT) [__LINUX_KERNEL_VERSION < 0x040200]: Undef.
* sysdeps/unix/sysv/linux/hppa/kernel-features.h
(__ASSUME_EXECVEAT) [__LINUX_KERNEL_VERSION < 0x040000]: Undef.
* sysdeps/unix/sysv/linux/microblaze/kernel-features.h
(__ASSUME_EXECVEAT) [__LINUX_KERNEL_VERSION < 0x040000]: Undef.
* posix/Makefile (tests): Add tst-fexecve.
* posix/tst-fexecve.c: New file.
2017-09-19 Wilco Dijkstra <wdijkstr@arm.com>
* benchtests/Makefile: Add logf benchmark.

2
posix/Makefile
View File

@ -93,7 +93,7 @@ tests := test-errno tstgetopt testfnm runtests runptests \
tst-fnmatch3 bug-regex36 tst-getaddrinfo5 \
tst-posix_spawn-fd tst-posix_spawn-setsid \
tst-posix_fadvise tst-posix_fadvise64 \
tst-sysconf-empty-chroot tst-glob_symlinks
tst-sysconf-empty-chroot tst-glob_symlinks tst-fexecve
tests-internal := bug-regex5 bug-regex20 bug-regex33 \
tst-rfc3484 tst-rfc3484-2 tst-rfc3484-3
xtests := bug-ga2

88
posix/tst-fexecve.c Normal file
View File

@ -0,0 +1,88 @@
/* Copyright (C) 2017 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
<http://www.gnu.org/licenses/>. */
#include <unistd.h>
#include <errno.h>
#include <fcntl.h>
#include <sys/wait.h>
#include <support/check.h>
/* Try executing "/bin/sh -c true", using FD opened on /bin/sh. */
static int
try_fexecve (int fd)
{
pid_t pid = fork ();
if (pid == 0)
{
static const char *const argv[] = {
"/bin/sh", "-c", "true", NULL
};
fexecve (fd, (char *const *) argv, environ);
_exit (errno);
}
if (pid < 0)
FAIL_RET ("fork failed: %m");
pid_t termpid;
int status;
termpid = TEMP_FAILURE_RETRY (waitpid (pid, &status, 0));
if (termpid == -1)
FAIL_RET ("waitpid failed: %m");
if (termpid != pid)
FAIL_RET ("waitpid returned %ld != %ld",
(long int) termpid, (long int) pid);
if (!WIFEXITED (status))
FAIL_RET ("child hasn't exited normally");
/* If fexecve is unimplemented mark this test as UNSUPPORTED. */
if (WEXITSTATUS (status) == ENOSYS)
FAIL_UNSUPPORTED ("fexecve is unimplemented");
if (WEXITSTATUS (status) != 0)
{
errno = WEXITSTATUS (status);
FAIL_RET ("fexecve failed: %m");
}
return 0;
}
static int
do_test (void)
{
int fd;
int ret;
fd = open ("/bin/sh", O_RDONLY);
if (fd < 0)
FAIL_UNSUPPORTED ("/bin/sh cannot be opened: %m");
ret = try_fexecve (fd);
close (fd);
#ifdef O_PATH
fd = open ("/bin/sh", O_RDONLY | O_PATH);
if (fd < 0)
FAIL_UNSUPPORTED ("/bin/sh cannot be opened (O_PATH): %m");
ret |= try_fexecve (fd);
close (fd);
#endif
return ret;
}
#include <support/test-driver.c>

5
sysdeps/unix/sysv/linux/alpha/kernel-features.h
View File

@ -35,4 +35,9 @@
#define __ASSUME_RECV_SYSCALL 1
#define __ASSUME_SEND_SYSCALL 1
/* Support for the execveat syscall was added in 4.2. */
#if __LINUX_KERNEL_VERSION < 0x040200
# undef __ASSUME_EXECVEAT
#endif
#endif /* _KERNEL_FEATURES_H */

15
sysdeps/unix/sysv/linux/fexecve.c
View File

@ -19,8 +19,13 @@
#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>
/* Execute the file FD refers to, overlaying the running program image.
ARGV and ENVP are passed to the new program, as for `execve'. */
@ -33,6 +38,15 @@ fexecve (int fd, char *const argv[], char *const envp[])
return -1;
}
#ifdef __NR_execveat
INLINE_SYSCALL (execveat, 5, fd, "", argv, envp, AT_EMPTY_PATH);
# ifndef __ASSUME_EXECVEAT
if (errno != ENOSYS)
return -1;
# endif
#endif
#ifndef __ASSUME_EXECVEAT
/* We use the /proc filesystem to get the information. If it is not
mounted we fail. */
char buf[sizeof "/proc/self/fd/" + sizeof (int) * 3];
@ -50,6 +64,7 @@ fexecve (int fd, char *const argv[], char *const envp[])
save = ENOSYS;
__set_errno (save);
#endif
return -1;
}

5
sysdeps/unix/sysv/linux/hppa/kernel-features.h
View File

@ -27,3 +27,8 @@
#define __ASSUME_RECV_SYSCALL 1
#define __ASSUME_SEND_SYSCALL 1
/* Support for the execveat syscall was added in 4.0. */
#if __LINUX_KERNEL_VERSION < 0x040000
# undef __ASSUME_EXECVEAT
#endif

5
sysdeps/unix/sysv/linux/kernel-features.h
View File

@ -102,3 +102,8 @@
implementation does not assume the __ASSUME_* and instead use a fallback
implementation based on p{read,write}v and returning an error for
non supported flags. */
/* Support for the execveat syscall was added in 3.19. */
#if __LINUX_KERNEL_VERSION >= 0x031300
# define __ASSUME_EXECVEAT 1
#endif

5
sysdeps/unix/sysv/linux/microblaze/kernel-features.h
View File

@ -47,3 +47,8 @@
#if __LINUX_KERNEL_VERSION < 0x030300
# undef __ASSUME_SENDMMSG_SYSCALL
#endif
/* Support for the execveat syscall was added in 4.0. */
#if __LINUX_KERNEL_VERSION < 0x040000
# undef __ASSUME_EXECVEAT
#endif