glibc/sysdeps/unix/sysv/linux/fexecve.c

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/* Copyright (C) 1994-2020 Free Software Foundation, Inc.
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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
Prefer https to http for gnu.org and fsf.org URLs Also, change sources.redhat.com to sourceware.org. This patch was automatically generated by running the following shell script, which uses GNU sed, and which avoids modifying files imported from upstream: sed -ri ' s,(http|ftp)(://(.*\.)?(gnu|fsf|sourceware)\.org($|[^.]|\.[^a-z])),https\2,g s,(http|ftp)(://(.*\.)?)sources\.redhat\.com($|[^.]|\.[^a-z]),https\2sourceware.org\4,g ' \ $(find $(git ls-files) -prune -type f \ ! -name '*.po' \ ! -name 'ChangeLog*' \ ! -path COPYING ! -path COPYING.LIB \ ! -path manual/fdl-1.3.texi ! -path manual/lgpl-2.1.texi \ ! -path manual/texinfo.tex ! -path scripts/config.guess \ ! -path scripts/config.sub ! -path scripts/install-sh \ ! -path scripts/mkinstalldirs ! -path scripts/move-if-change \ ! -path INSTALL ! -path locale/programs/charmap-kw.h \ ! -path po/libc.pot ! -path sysdeps/gnu/errlist.c \ ! '(' -name configure \ -execdir test -f configure.ac -o -f configure.in ';' ')' \ ! '(' -name preconfigure \ -execdir test -f preconfigure.ac ';' ')' \ -print) and then by running 'make dist-prepare' to regenerate files built from the altered files, and then executing the following to cleanup: chmod a+x sysdeps/unix/sysv/linux/riscv/configure # Omit irrelevant whitespace and comment-only changes, # perhaps from a slightly-different Autoconf version. git checkout -f \ sysdeps/csky/configure \ sysdeps/hppa/configure \ sysdeps/riscv/configure \ sysdeps/unix/sysv/linux/csky/configure # Omit changes that caused a pre-commit check to fail like this: # remote: *** error: sysdeps/powerpc/powerpc64/ppc-mcount.S: trailing lines git checkout -f \ sysdeps/powerpc/powerpc64/ppc-mcount.S \ sysdeps/unix/sysv/linux/s390/s390-64/syscall.S # Omit change that caused a pre-commit check to fail like this: # remote: *** error: sysdeps/sparc/sparc64/multiarch/memcpy-ultra3.S: last line does not end in newline git checkout -f sysdeps/sparc/sparc64/multiarch/memcpy-ultra3.S
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<https://www.gnu.org/licenses/>. */
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#include <errno.h>
#include <stddef.h>
#include <stdio.h>
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#include <unistd.h>
#include <fcntl.h>
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#include <sys/stat.h>
#include <sysdep.h>
#include <sys/syscall.h>
#include <kernel-features.h>
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/* Execute the file FD refers to, overlaying the running program image.
ARGV and ENVP are passed to the new program, as for `execve'. */
int
fexecve (int fd, char *const argv[], char *const envp[])
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{
if (fd < 0 || argv == NULL || envp == NULL)
{
__set_errno (EINVAL);
return -1;
}
#ifdef __NR_execveat
Fix fexecve build where syscall macros call sizeof. The recent fexecve changes broke the build on (at least) alpha (maybe other configurations, that was the first breakage I saw in my build-many-glibcs.py run): In file included from ../sysdeps/unix/sysv/linux/alpha/sysdep.h:29:0, from ../sysdeps/alpha/nptl/tls.h:31, from ../include/errno.h:25, from ../sysdeps/unix/sysv/linux/fexecve.c:18: ../sysdeps/unix/sysv/linux/fexecve.c: In function 'fexecve': ../sysdeps/unix/alpha/sysdep.h:203:10: error: 'sizeof' on array function parameter 'argv' will return size of 'char * const*' [-Werror=sizeof-array-argument] (sizeof(arg) == 4 ? (long)(int)(long)(arg) : (long)(arg)) ^ ../sysdeps/unix/alpha/sysdep.h:302:26: note: in expansion of macro 'syscall_promote' register long _tmp_18 = syscall_promote (arg3); \ ^~~~~~~~~~~~~~~ ../sysdeps/unix/alpha/sysdep.h:173:2: note: in expansion of macro 'inline_syscall5' inline_syscall##nr(__NR_##name, args); \ ^~~~~~~~~~~~~~ ../sysdeps/unix/sysv/linux/alpha/sysdep.h:85:2: note: in expansion of macro 'INLINE_SYSCALL1' INLINE_SYSCALL1(name, nr, args); \ ^~~~~~~~~~~~~~~ ../sysdeps/unix/sysv/linux/fexecve.c:42:3: note: in expansion of macro 'INLINE_SYSCALL' INLINE_SYSCALL (execveat, 5, fd, "", argv, envp, AT_EMPTY_PATH); ^~~~~~~~~~~~~~ ../sysdeps/unix/sysv/linux/fexecve.c:33:30: note: declared here fexecve (int fd, char *const argv[], char *const envp[]) ^~~~ This patch fixes this similarly to previous fixes for such issues: use &argv[0] and &envp[0] as the syscall macro arguments. Tested (compilation only) for alpha-linux-gnu with build-many-glibcs.py. * sysdeps/unix/sysv/linux/fexecve.c (fexecve) [__NR_execveat]: Explicitly take address of first element of array arguments in call to INLINE_SYSCALL.
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/* Avoid implicit array coercion in syscall macros. */
INLINE_SYSCALL (execveat, 5, fd, "", &argv[0], &envp[0], AT_EMPTY_PATH);
# ifndef __ASSUME_EXECVEAT
if (errno != ENOSYS)
return -1;
# endif
#endif
#ifndef __ASSUME_EXECVEAT
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/* 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];
__snprintf (buf, sizeof (buf), "/proc/self/fd/%d", fd);
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/* We do not need the return value. */
__execve (buf, argv, envp);
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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;
__set_errno (save);
#endif
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return -1;
}