From: Adhemerval Zanella via Libc-alpha <libc-alpha@sourceware.org>
To: libc-alpha@sourceware.org, "Alexandra Hájková" <ahajkova@redhat.com>
Subject: Re: [PATCH] Linux: Add execveat system call wrapper
Date: Mon, 9 Nov 2020 17:39:57 -0300 [thread overview]
Message-ID: <8e4bcdfa-0ecd-b076-a2a7-2cac9cb419b2@linaro.org> (raw)
In-Reply-To: <20200428122019.26826-1-ahajkova@redhat.com>
On 28/04/2020 09:20, Alexandra Hájková via Libc-alpha wrote:
> From: Alexandra Hájková <ahajkova@redhat.com>
> diff --git a/sysdeps/unix/sysv/linux/bits/unistd_ext.h b/sysdeps/unix/sysv/linux/bits/unistd_ext.h
> index c315cc5cb8..55225b5447 100644
> --- a/sysdeps/unix/sysv/linux/bits/unistd_ext.h
> +++ b/sysdeps/unix/sysv/linux/bits/unistd_ext.h
> @@ -17,7 +17,7 @@
> <https://www.gnu.org/licenses/>. */
>
> #ifndef _UNISTD_H
> -# error "Never include <bits/unistd_ext.h> directly; use <unistd.h> instead."
> +#error "Never include <bits/unistd_ext.h> directly; use <unistd.h> instead."
> #endif
>
Spurious change.
> #ifdef __USE_GNU
> @@ -33,4 +33,9 @@
> not detached and has not been joined. */
> extern __pid_t gettid (void) __THROW;
>
> +/* Execute program relative to a directory file descriptor. */
> + extern int execveat (int __fd, const char *__path, char *const __argv[],
> + char *const __envp[], int __flags)
> + __THROW __nonnull ((2, 3));
> +
Indentation seems off here (extra space before extern).
> #endif
> diff --git a/sysdeps/unix/sysv/linux/execveat.c b/sysdeps/unix/sysv/linux/execveat.c
> new file mode 100644
> index 0000000000..7ebf397091
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/execveat.c
> @@ -0,0 +1,67 @@
> +/* Copyright (C) 1994-2020 Free Software Foundation, Inc.
I think it should be solely 2020.
> + 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>
> +
> +
> +/* 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;
> +
> + int fd = openat (dirfd, path, flags | O_CLOEXEC);
This will turn execevat in a cancellation entrypoint.
> + if (fd < 0)
> + return -1;
> +
> + struct fd_to_filename fdfilename;
> + const char *gfilename
> + = path != NULL ? path : __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;
Not sure if it would make a difference here, but I think it would be
better to use the LFS interface here.
> diff --git a/sysdeps/unix/sysv/linux/tst-execveat.c b/sysdeps/unix/sysv/linux/tst-execveat.c
> new file mode 100644
> index 0000000000..06c4e9fc4b
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/tst-execveat.c
> @@ -0,0 +1,68 @@
> +/* Copyright (C) 2017-2020 Free Software Foundation, Inc.
Same as before, I think the Copyright year should be only 2020.
> + 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 <sys/types.h>
> +#include <dirent.h>
> +#include <support/check.h>
> +#include <support/xdlfcn.h>
> +#include <support/xstdio.h>
> +#include <support/xunistd.h>
> +#include <wait.h>
> +
> +static int
> +do_test (void)
> +{
> + char *argv[] = { (char *) "-c", (char *) "exit 3", NULL };
> + char *envp[] = { (char *) "FOO=BAR", NULL };
Maybe add a check if the environment variable is what you expect (to
check if envp passing is ok)?
> + DIR *dirp;
> + int fd;
> + pid_t pid;
> + int status;
> +
> + dirp = opendir ("/bin");
> + if (!dirp)
> + FAIL_EXIT1 ("failed to open /bin");
> + fd = dirfd (dirp);
> +
> + errno = 0;
> + pid = xfork ();
> + if (pid == 0)
> + {
> + execveat (fd, "sh", argv, envp, 0);
> +
> + if (errno)
Don't use implicit checks.
> + {
> + closedir (dirp);
> + FAIL_EXIT1 ("execveat failed, errno %d", errno);
> + }
> + }
> + xwaitpid (pid, &status, 0);
> +
> + if (WIFEXITED (status))
> + TEST_COMPARE (WEXITSTATUS (status), 3);
> + else
> + {
> + closedir (dirp);
> + FAIL_EXIT1 ("execveat failed");
> + }
> +
> + closedir (dirp);
> + return 0;
> +}
> +
> +#include <support/test-driver.c>
Besides the points raised by Joseph, the rest looks ok. I didn't check if it
updates all the abilist files.
next prev parent reply other threads:[~2020-11-09 20:40 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-28 12:20 [PATCH] Linux: Add execveat system call wrapper Alexandra Hájková via Libc-alpha
2020-04-28 14:17 ` Florian Weimer
2020-04-28 15:03 ` Joseph Myers
2020-04-28 15:03 ` Joseph Myers
2020-04-28 15:08 ` Florian Weimer
2020-04-28 15:29 ` Joseph Myers
2020-04-28 17:15 ` Florian Weimer
2020-04-28 17:19 ` Joseph Myers
2020-04-28 17:44 ` Adhemerval Zanella via Libc-alpha
2020-04-28 17:50 ` Florian Weimer
2020-04-28 18:31 ` Adhemerval Zanella via Libc-alpha
2020-04-30 11:15 ` Florian Weimer via Libc-alpha
2020-04-30 12:28 ` Adhemerval Zanella via Libc-alpha
2020-04-30 12:55 ` Florian Weimer via Libc-alpha
2020-04-30 19:03 ` Adhemerval Zanella via Libc-alpha
2020-04-30 12:32 ` Adhemerval Zanella via Libc-alpha
2020-11-06 21:03 ` Alexandra Hájková via Libc-alpha
2020-11-06 22:15 ` Joseph Myers
2020-11-09 18:43 ` Florian Weimer via Libc-alpha
2020-11-09 21:34 ` Yann Droneaud
2020-11-26 11:31 ` Alexandra Petlanova Hajkova via Libc-alpha
2020-11-09 20:39 ` Adhemerval Zanella via Libc-alpha [this message]
2020-12-03 13:55 ` Florian Weimer via Libc-alpha
2020-11-26 21:28 ` Alexandra Hájková via Libc-alpha
2020-11-27 14:58 ` Adhemerval Zanella via Libc-alpha
2020-11-27 17:32 ` Florian Weimer via Libc-alpha
2020-11-27 17:38 ` Adhemerval Zanella via Libc-alpha
2020-12-03 14:20 ` Alexandra Hájková via Libc-alpha
2020-12-03 14:37 ` Andreas Schwab
2020-12-08 14:44 ` Adhemerval Zanella via Libc-alpha
2020-12-08 15:18 ` Florian Weimer via Libc-alpha
2020-12-08 16:41 ` Adhemerval Zanella via Libc-alpha
2021-03-15 21:42 ` Alexandra Hájková via Libc-alpha
2021-03-15 22:12 ` Joseph Myers
2021-03-15 22:17 ` Dmitry V. Levin
2021-03-24 13:54 ` Alexandra Hájková via Libc-alpha
2021-03-26 20:36 ` Adhemerval Zanella via Libc-alpha
2021-04-02 12:13 ` Alexandra Hájková via Libc-alpha
2021-04-02 13:29 ` Adhemerval Zanella via Libc-alpha
2021-04-05 16:32 ` Alexandra Hájková via Libc-alpha
2021-04-12 10:26 ` Alexandra Hájková via Libc-alpha
2021-04-12 11:14 ` Andreas Schwab
2021-04-12 19:26 ` Alexandra Hájková via Libc-alpha
2021-04-13 19:27 ` Adhemerval Zanella via Libc-alpha
2021-04-21 18:11 ` Alexandra Hájková via Libc-alpha
2021-05-03 19:20 ` Adhemerval Zanella via Libc-alpha
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