glibc/io/openat.c

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/* Copyright (C) 2005-2017 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 <errno.h>
#include <fcntl.h>
#include <stdarg.h>
#include <stddef.h>
#include <stdio.h>
#include <sys/stat.h>
#include <kernel-features.h>
/* Some mostly-generic code (e.g. sysdeps/posix/getcwd.c) uses this variable
if __ASSUME_ATFCTS is not defined. */
#ifndef __ASSUME_ATFCTS
int __have_atfcts;
#endif
/* Open FILE with access OFLAG. Interpret relative paths relative to
linux: open and openat ignore 'mode' with O_TMPFILE in flags Both open and openat load their last argument 'mode' lazily, using va_arg() only if O_CREAT is found in oflag. This is wrong, mode is also necessary if O_TMPFILE is in oflag. By chance on x86_64, the problem wasn't evident when using O_TMPFILE with open, as the 3rd argument of open, even when not loaded with va_arg, is left untouched in RDX, where the syscall expects it. However, openat was not so lucky, and O_TMPFILE couldn't be used: mode is the 4th argument, in RCX, but the syscall expects its 4th argument in a different register than the glibc wrapper, in R10. Introduce a macro __OPEN_NEEDS_MODE (oflag) to test if either O_CREAT or O_TMPFILE is set in oflag. Tested on Linux x86_64. [BZ #17523] * io/fcntl.h (__OPEN_NEEDS_MODE): New macro. * io/bits/fcntl2.h (open): Use it. (openat): Likewise. * io/open.c (__libc_open): Likewise. * io/open64.c (__libc_open64): Likewise. * io/open64_2.c (__open64_2): Likewise. * io/open_2.c (__open_2): Likewise. * io/openat.c (__openat): Likewise. * io/openat64.c (__openat64): Likewise. * io/openat64_2.c (__openat64_2): Likewise. * io/openat_2.c (__openat_2): Likewise. * sysdeps/mach/hurd/open.c (__libc_open): Likewise. * sysdeps/mach/hurd/openat.c (__openat): Likewise. * sysdeps/posix/open64.c (__libc_open64): Likewise. * sysdeps/unix/sysv/linux/dl-openat64.c (openat64): Likewise. * sysdeps/unix/sysv/linux/generic/open.c (__libc_open): Likewise. (__open_nocancel): Likewise. * sysdeps/unix/sysv/linux/generic/open64.c (__libc_open64): Likewise. * sysdeps/unix/sysv/linux/open64.c (__libc_open64): Likewise. * sysdeps/unix/sysv/linux/openat.c (__OPENAT): Likewise.
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the directory associated with FD. If O_CREAT or O_TMPFILE is in OFLAG, a
third argument is the file protection. */
int
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__openat (int fd, const char *file, int oflag, ...)
{
int mode;
if (file == NULL)
{
__set_errno (EINVAL);
return -1;
}
* io/Makefile (routines): Add fstatat, fstatat64, fxstatat, fxstatat64, fchownat, and unlinkat. (static-only-routines): Add fstatat and fstatat64. (tests): Add tst-unlinkat, tst-fstatat, tst-futimesat, tst-renameat, and tst-fchownat. * io/Versions [GLIBC_2.4]: Add fchownat, __fxstatat, __fxstatat64, and unlinkat. * io/fcntl.h: Define AT_FDCWD, AT_SYMLINK_NOFOLLOW, and AT_REMOVEDIR. * io/fstatat.c: New file. * io/fstatat64.c: New file. * io/sys/stat.h: Declare fstatat, fstatat64, __fxstatat, __fxstatat64 and define fstatat and fstatat64 inline functions. * libio/stdio.h: Declare renameat. * misc/Makefile (routines): Add futimesat. * misc/Versions [GLIBC_2.4]: Add futimesat. * posix/unistd.h: Declare fchownat and unlinkat. * stdio-common/Makefile (routines): Add renameat. * stdio-common/Versions [GLIBC_2.4]: Add renameat. * sysdeps/generic/fchownat.c: New file. * sysdeps/generic/futimesat.c: New file. * sysdeps/generic/fxstatat.c: New file. * sysdeps/generic/fxstatat64.c: New file. * sysdeps/generic/renameat.c: New file. * sysdeps/generic/unlinkat.c: New file. * sysdeps/unix/sysv/linux/fchownat.c: New file. * sysdeps/unix/sysv/linux/futimesat.c: New file. * sysdeps/unix/sysv/linux/fxstatat.c: New file. * sysdeps/unix/sysv/linux/fxstatat64.c: New file. * sysdeps/unix/sysv/linux/renameat.c: New file. * sysdeps/unix/sysv/linux/unlinkat.c: New file. * sysdeps/unix/sysv/linux/alpha/fxstatat.c: New file. * sysdeps/unix/sysv/linux/i386/fchownat.c: New file. * sysdeps/unix/sysv/linux/i386/fxstatat.c: New file. * sysdeps/unix/sysv/linux/m68k/fchownat.c: New file. * sysdeps/unix/sysv/linux/m68k/fxstatat.c: New file. * sysdeps/unix/sysv/linux/powerpc/fchownat.c: New file. * sysdeps/unix/sysv/linux/powerpc/powerpc32/fxstatat.c: New file. * sysdeps/unix/sysv/linux/s390/s390-32/fchownat.c: New file. * sysdeps/unix/sysv/linux/s390/s390-32/fxstatat.c: New file. * sysdeps/unix/sysv/linux/sh/fchownat.c: New file. * sysdeps/unix/sysv/linux/sh/fxstatat.c: New file. * sysdeps/unix/sysv/linux/sparc/sparc32/fchownat.c: New file. * sysdeps/unix/sysv/linux/sparc/sparc32/fxstatat.c: New file. * sysdeps/unix/sysv/linux/sparc/sparc64/fxstatat.c: New file. * sysdeps/unix/sysv/linux/wordsize-64/fxstatat.c: New file. * sysdeps/unix/sysv/linux/wordsize-64/fxstatat64.c: New file. * time/sys/time.h: Declare futimesat. * include/fcntl.h: Declare __atfct_seterrno. * sysdeps/unix/sysv/linux/openat.c (__atfct_seterrno): New function. Split out from openat code and called. (do_test): Allow openat to fail with ENOSYS. Handle AT_FDCWD. * sysdeps/generic/openat.c: Handle AT_FDCWD. * sysdeps/generic/openat64.c: Likewise. * io/tst-unlinkat.c: New file. * io/tst-fstatat.c: New file. * io/tst-futimesat.c: New file. * io/tst-renameat.c: New file. * io/tst-fchownat.c: New file. * io/tst-openat.c: Don't fail if openat is not implemented. * sysdeps/unix/sysv/linux/powerpc/chown.c: Don't provide backward compatibility code if new kernel is guaranteed. * time/sys/time.h: Add a few nonnull attributes.
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if (fd != AT_FDCWD && file[0] != '/')
{
/* Check FD is associated with a directory. */
struct stat64 st;
if (__fxstat64 (_STAT_VER, fd, &st) != 0)
return -1;
if (!S_ISDIR (st.st_mode))
{
__set_errno (ENOTDIR);
return -1;
}
}
linux: open and openat ignore 'mode' with O_TMPFILE in flags Both open and openat load their last argument 'mode' lazily, using va_arg() only if O_CREAT is found in oflag. This is wrong, mode is also necessary if O_TMPFILE is in oflag. By chance on x86_64, the problem wasn't evident when using O_TMPFILE with open, as the 3rd argument of open, even when not loaded with va_arg, is left untouched in RDX, where the syscall expects it. However, openat was not so lucky, and O_TMPFILE couldn't be used: mode is the 4th argument, in RCX, but the syscall expects its 4th argument in a different register than the glibc wrapper, in R10. Introduce a macro __OPEN_NEEDS_MODE (oflag) to test if either O_CREAT or O_TMPFILE is set in oflag. Tested on Linux x86_64. [BZ #17523] * io/fcntl.h (__OPEN_NEEDS_MODE): New macro. * io/bits/fcntl2.h (open): Use it. (openat): Likewise. * io/open.c (__libc_open): Likewise. * io/open64.c (__libc_open64): Likewise. * io/open64_2.c (__open64_2): Likewise. * io/open_2.c (__open_2): Likewise. * io/openat.c (__openat): Likewise. * io/openat64.c (__openat64): Likewise. * io/openat64_2.c (__openat64_2): Likewise. * io/openat_2.c (__openat_2): Likewise. * sysdeps/mach/hurd/open.c (__libc_open): Likewise. * sysdeps/mach/hurd/openat.c (__openat): Likewise. * sysdeps/posix/open64.c (__libc_open64): Likewise. * sysdeps/unix/sysv/linux/dl-openat64.c (openat64): Likewise. * sysdeps/unix/sysv/linux/generic/open.c (__libc_open): Likewise. (__open_nocancel): Likewise. * sysdeps/unix/sysv/linux/generic/open64.c (__libc_open64): Likewise. * sysdeps/unix/sysv/linux/open64.c (__libc_open64): Likewise. * sysdeps/unix/sysv/linux/openat.c (__OPENAT): Likewise.
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if (__OPEN_NEEDS_MODE (oflag))
{
va_list arg;
va_start (arg, oflag);
mode = va_arg (arg, int);
va_end (arg);
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ignore_value (mode);
}
__set_errno (ENOSYS);
return -1;
}
libc_hidden_def (__openat)
weak_alias (__openat, openat)
stub_warning (openat)
/* __openat_2 is a generic wrapper that calls __openat.
So give a stub warning for that symbol too. */
stub_warning (__openat_2)