Avoid cancellable I/O primitives in ld.so.
Neither the <dlfcn.h> entry points, nor lazy symbol resolution, nor
initial shared library load-up, are cancellation points, so ld.so
should exclusively use I/O primitives that are not cancellable. We
currently achieve this by having the cancellation hooks compile as
no-ops when IS_IN(rtld); this patch changes to using exclusively
_nocancel primitives in the source code instead, which makes the
intent clearer and significantly reduces the amount of code compiled
under IS_IN(rtld) as well as IS_IN(libc) -- in particular,
elf/Makefile no longer thinks we require a copy of unwind.c in
rtld-libc.a. (The older mechanism is preserved as a backstop.)
The bulk of the change is splitting up the files that define the
_nocancel I/O functions, so they don't also define the variants that
*are* cancellation points; after which, the existing logic for picking
out the bits of libc that need to be recompiled as part of ld.so Just
Works. I did this for all of the _nocancel functions, not just the
ones used by ld.so, for consistency.
fcntl was a little tricky because it's only a cancellation point for
certain opcodes (F_SETLKW(64), which can block), and the existing
__fcntl_nocancel wasn't applying the FCNTL_ADJUST_CMD hook, which
strikes me as asking for trouble, especially as the only nontrivial
definition of FCNTL_ADJUST_CMD (for powerpc64) changes F_*LK* opcodes.
To fix this, fcntl_common moves to fcntl_nocancel.c along with
__fcntl_nocancel, and changes its name to the extern (but hidden)
symbol __fcntl_nocancel_adjusted, so that regular fcntl can continue
calling it. __fcntl_nocancel now applies FCNTL_ADJUST_CMD; so that
both both fcntl.c and fcntl_nocancel.c can see it, the only nontrivial
definition moves from sysdeps/u/s/l/powerpc/powerpc64/fcntl.c to
.../powerpc64/sysdep.h and becomes entirely a macro, instead of a macro
that calls an inline function.
The nptl version of libpthread also changes a little, because its
"compat-routines" formerly included files that defined all the
_nocancel functions it uses; instead of continuing to duplicate them,
I exported the relevant ones from libc.so as GLIBC_PRIVATE. Since the
Linux fcntl.c calls a function defined by fcntl_nocancel.c, it can no
longer be used from libpthread.so; instead, introduce a custom
forwarder, pt-fcntl.c, and export __libc_fcntl from libc.so as
GLIBC_PRIVATE. The nios2-linux ABI doesn't include a copy of vfork()
in libpthread, and it was handling that by manipulating
libpthread-routines in .../linux/nios2/Makefile; it is cleaner to do
what other such ports do, and have a pt-vfork.S that defines no symbols.
Right now, it appears that Hurd does not implement _nocancel I/O, so
sysdeps/generic/not-cancel.h will forward everything back to the
regular functions. This changed the names of some of the functions
that sysdeps/mach/hurd/dl-sysdep.c needs to interpose.
* elf/dl-load.c, elf/dl-misc.c, elf/dl-profile.c, elf/rtld.c
* sysdeps/unix/sysv/linux/dl-sysdep.c
Include not-cancel.h. Use __close_nocancel instead of __close,
__open64_nocancel instead of __open, __read_nocancel instead of
__libc_read, and __write_nocancel instead of __libc_write.
* csu/check_fds.c (check_one_fd)
* sysdeps/posix/fdopendir.c (__fdopendir)
* sysdeps/posix/opendir.c (__alloc_dir): Use __fcntl_nocancel
instead of __fcntl and/or __libc_fcntl.
* sysdeps/unix/sysv/linux/pthread_setname.c (pthread_setname_np)
* sysdeps/unix/sysv/linux/pthread_getname.c (pthread_getname_np)
* sysdeps/unix/sysv/linux/i386/smp.h (is_smp_system):
Use __open64_nocancel instead of __open_nocancel.
* sysdeps/unix/sysv/linux/not-cancel.h: Move all of the
hidden_proto declarations to the end and issue them if either
IS_IN(libc) or IS_IN(rtld).
* sysdeps/unix/sysv/linux/Makefile [subdir=io] (sysdep_routines):
Add close_nocancel, fcntl_nocancel, nanosleep_nocancel,
open_nocancel, open64_nocancel, openat_nocancel, pause_nocancel,
read_nocancel, waitpid_nocancel, write_nocancel.
* io/Versions [GLIBC_PRIVATE]: Add __libc_fcntl,
__fcntl_nocancel, __open64_nocancel, __write_nocancel.
* posix/Versions: Add __nanosleep_nocancel, __pause_nocancel.
* nptl/pt-fcntl.c: New file.
* nptl/Makefile (pthread-compat-wrappers): Remove fcntl.
(libpthread-routines): Add pt-fcntl.
* include/fcntl.h (__fcntl_nocancel_adjusted): New function.
(__libc_fcntl): Remove attribute_hidden.
* sysdeps/unix/sysv/linux/fcntl.c (__libc_fcntl): Call
__fcntl_nocancel_adjusted, not fcntl_common.
(__fcntl_nocancel): Move to new file fcntl_nocancel.c.
(fcntl_common): Rename to __fcntl_nocancel_adjusted; also move
to fcntl_nocancel.c.
* sysdeps/unix/sysv/linux/fcntl_nocancel.c: New file.
* sysdeps/unix/sysv/linux/powerpc/powerpc64/fcntl.c: Remove file.
* sysdeps/unix/sysv/linux/powerpc/powerpc64/sysdep.h:
Define FCNTL_ADJUST_CMD here, as a self-contained macro.
* sysdeps/unix/sysv/linux/close.c: Move __close_nocancel to...
* sysdeps/unix/sysv/linux/close_nocancel.c: ...this new file.
* sysdeps/unix/sysv/linux/nanosleep.c: Move __nanosleep_nocancel to...
* sysdeps/unix/sysv/linux/nanosleep_nocancel.c: ...this new file.
* sysdeps/unix/sysv/linux/open.c: Move __open_nocancel to...
* sysdeps/unix/sysv/linux/open_nocancel.c: ...this new file.
* sysdeps/unix/sysv/linux/open64.c: Move __open64_nocancel to...
* sysdeps/unix/sysv/linux/open64_nocancel.c: ...this new file.
* sysdeps/unix/sysv/linux/openat.c: Move __openat_nocancel to...
* sysdeps/unix/sysv/linux/openat_nocancel.c: ...this new file.
* sysdeps/unix/sysv/linux/openat64.c: Move __openat64_nocancel to...
* sysdeps/unix/sysv/linux/openat64_nocancel.c: ...this new file.
* sysdeps/unix/sysv/linux/pause.c: Move __pause_nocancel to...
* sysdeps/unix/sysv/linux/pause_nocancel.c: ...this new file.
* sysdeps/unix/sysv/linux/read.c: Move __read_nocancel to...
* sysdeps/unix/sysv/linux/read_nocancel.c: ...this new file.
* sysdeps/unix/sysv/linux/waitpid.c: Move __waitpid_nocancel to...
* sysdeps/unix/sysv/linux/waitpid_nocancel.c: ...this new file.
* sysdeps/unix/sysv/linux/write.c: Move __write_nocancel to...
* sysdeps/unix/sysv/linux/write_nocancel.c: ...this new file.
* sysdeps/unix/sysv/linux/nios2/Makefile: Don't override
libpthread-routines.
* sysdeps/unix/sysv/linux/nios2/pt-vfork.S: New file which
defines nothing.
* sysdeps/mach/hurd/dl-sysdep.c: Define __read instead of
__libc_read, and __write instead of __libc_write. Define
__open64 in addition to __open.
2018-04-03 22:26:44 +00:00
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/* Linux openat syscall implementation, non-LFS.
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2019-01-01 00:11:28 +00:00
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Copyright (C) 2005-2019 Free Software Foundation, Inc.
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2005-11-10 00:12:21 +00:00
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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2012-02-09 23:18:22 +00:00
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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2005-11-10 00:12:21 +00:00
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#include <fcntl.h>
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#include <stdarg.h>
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2017-06-20 18:46:28 +00:00
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#include <sysdep-cancel.h>
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2006-03-01 05:32:59 +00:00
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2017-06-20 18:46:28 +00:00
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#ifndef __OFF_T_MATCHES_OFF64_T
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2006-02-12 21:41:44 +00:00
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/* Open FILE with access OFLAG. Interpret relative paths relative to
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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.
2015-02-24 07:42:26 +00:00
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the directory associated with FD. If OFLAG includes O_CREAT or
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O_TMPFILE, a fourth argument is the file protection. */
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2006-02-12 21:41:44 +00:00
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int
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2017-06-20 18:46:28 +00:00
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__libc_openat (int fd, const char *file, int oflag, ...)
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2006-02-12 21:41:44 +00:00
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{
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mode_t mode = 0;
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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.
2015-02-24 07:42:26 +00:00
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if (__OPEN_NEEDS_MODE (oflag))
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2006-02-12 21:41:44 +00:00
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{
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va_list arg;
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va_start (arg, oflag);
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mode = va_arg (arg, mode_t);
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va_end (arg);
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}
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nptl: Rewrite cancellation macros
This patch changes the way cancellation entrypoints are defined to
instead call the macro SYSCALL_CANCEL. An usual cnacellation definition
is defined as:
if (SINGLE_THREAD_P)
return INLINE_SYSCALL (syscall, NARGS, args...)
int oldtype = LIBC_CANCEL_ASYNC ();
return INLINE_SYSCALL (syscall, NARGS, args...)
LIBC_CANCEL_RESET (oldtype);
And it is rewrited as just:
SYSCALL_CANCEL (syscall, args...)
The idea is to remove LIBC_CANCEL_ASYNC/LIBC_CANCEL_RESET explicit
usage.
Tested on i386, x86_64, powerpc32, powerpc64le, arm, and aarch64.
* sysdeps/unix/sysdep.h [SYSCALL_CANCEL]: New macro: define
cancellable syscalls.
(SYS_ify): Add guard to no redefine it.
(INLINE_SYSCALL): Likewise.
* sysdeps/unix/sysv/linux/accept4.c (accept4): Remove
LIBC_CANCEL_ASYNC/INLINE_SYSCALL/LIBC_CANCEL_RESET and use
SYSCALL_CANCEL instead.
* sysdeps/unix/sysv/linux/alpha/fdatasync.c (__fdatasync): Likewise.
* sysdeps/unix/sysv/linux/arm/pread.c (__libc_pread): Likewise.
* sysdeps/unix/sysv/linux/arm/pread64.c (__libc_pread64): Likewise.
* sysdeps/unix/sysv/linux/arm/pwrite.c (__libc_pwrite): Likewise.
* sysdeps/unix/sysv/linux/arm/pwrite64.c (__libc_pwrite64): Likewise.
* sysdeps/unix/sysv/linux/epoll_pwait.c (epoll_pwait): Likewise.
* sysdeps/unix/sysv/linux/fallocate.c (fallocate): Likewise.
* sysdeps/unix/sysv/linux/fallocate64.c (fallocate64): Likewise.
* sysdeps/unix/sysv/linux/generic/open.c (__libc_open): Likewise.
* sysdeps/unix/sysv/linux/generic/open64.c (__libc_open64): Likewise.
* sysdeps/unix/sysv/linux/generic/pause.c (__libc_pause): Likewise.
* sysdeps/unix/sysv/linux/generic/poll.c (__poll): Likewise.
* sysdeps/unix/sysv/linux/generic/recv.c (__libc_recv): Likewise.
* sysdeps/unix/sysv/linux/generic/select.c (__select): Likewise.
* sysdeps/unix/sysv/linux/generic/send.c (__libc_send): Likewise.
* sysdeps/unix/sysv/linux/generic/wordsize-32/pread.c (__libc_pread):
Likewise.
* sysdeps/unix/sysv/linux/generic/wordsize-32/pread64.c
(__libc_pread64): Likewise.
* sysdeps/unix/sysv/linux/generic/wordsize-32/preadv.c
(__libc_preadv): Likewise.
* sysdeps/unix/sysv/linux/generic/wordsize-32/preadv64.c
(__libc_readv64): Likewise.
* sysdeps/unix/sysv/linux/generic/wordsize-32/pwrite.c
(__libc_pwrite): Likewise.
* sysdeps/unix/sysv/linux/generic/wordsize-32/pwrite64.c
(__libc_pwrite64): Likewise.
* sysdeps/unix/sysv/linux/generic/wordsize-32/pwritev.c
(__libc_pwritev): Likewise.
* sysdeps/sysv/linux/generic/wordsize-32/pwritev64.c
(__libc_pwritev64): Likewise.
* sysdeps/unix/sysv/linux/i386/fcntl.c (__libc_fcntl): Likewise.
* sysdeps/unix/sysv/linux/mips/mips32/sync_file_range.c
(sync_file_range): Likewise.
* sysdeps/unix/sysv/linux/mips/mips64/n32/fallocate.c (fallocate):
Likewise.
* sysdeps/unix/sysv/linux/mips/mips64/n32/fallocate64.c (fallocate64):
Likewise.
* sysdeps/unix/sysv/linux/mips/pread.c (__libc_pread): Likewise.
* sysdeps/unix/sysv/linux/mips/pread64.c (__libc_pread64): Likewise.
* sysdeps/unix/sysv/linux/mips/pwrite.c (__libc_pwrite): Likewise.
* sysdeps/unix/sysv/linux/mips/pwrite64.c (__libc_pwrite64): Likewise.
* sysdeps/unix/sysv/linux/msgrcv.c (__libc_msgrcv): Likewise.
* sysdeps/unix/sysv/linux/msgsnd.c (__libc_msgsnd): Likewise.
* sysdeps/unix/sysv/linux/open64.c (__libc_open64): Likewise.
* sysdeps/unix/sysv/linux/openat.c (__libc_openat): Likewise.
* sysdeps/unix/sysv/linux/powerpc/powerpc32/pread.c (__libc_pread):
Likewise.
* sysdeps/unix/sysv/linux/powerpc/powerpc32/pread64.c
(__libc_read64): Likewise.
* sysdeps/unix/sysv/linux/powerpc/powerpc32/pwrite.c (__libc_write):
Likewise.
* sysdeps/unix/sysv/linux/powerpc/powerpc32/pwrite64.c (__libc_write64):
Likewise.
* sysdeps/unix/sysv/linux/powerpc/powerpc64/fcntl.c (__libc_fcntl):
Likewise.
* sysdeps/unix/sysv/linux/powerpc/powerpc64/pread.c (__libc_pread):
Likewise.
* sysdeps/unix/sysv/linux/powerpc/powerpc64/pread64.c
(__libc_pread64): Likewise.
* sysdeps/unix/sysv/linux/powerpc/powerpc64/pwrite.c (__libc_pwrite):
Likewise.
* sysdeps/unix/sysv/linux/powerpc/powerpc64/pwrite64.c
(__libc_pwrite64): Likewise.
* sysdeps/sysv/linux/powerpc/powerpc64/sync_file_range.c
(sync_file_range): Likewise.
* sysdeps/unix/sysv/linux/ppoll.c (ppoll): Likewise.
* sysdeps/unix/sysv/linux/pread.c (__libc_pread): Likewise.
* sysdeps/unix/sysv/linux/pread64.c (__libc_pread64): Likewise.
* sysdeps/unix/sysv/linux/preadv.c (__libc_preadv): Likewise.
* sysdeps/unix/sysv/linux/pselect.c (__pselect): Likewise.
* sysdeps/unix/sysv/linux/pwrite.c (__libc_pwrite): Likewise.
* sysdeps/unix/sysv/linux/pwrite64.c (__libc_pwrite64): Likewise.
* sysdeps/unix/sysv/linux/pwritev.c (PWRITEV): Likewise.
* sysdeps/unix/sysv/linux/readv.c (__libc_readv): Likewise.
* sysdeps/unix/sysv/linux/recvmmsg.c (recvmmsg): Likewise.
* sysdeps/unix/sysv/linux/sendmmsg.c (sendmmsg): Likewise.
* sysdeps/unix/sysv/linux/sh/pread.c (__libc_pread): Likewise.
* sysdeps/unix/sysv/linux/sh/pread64.c (__libc_pread64): Likewise.
* sysdeps/unix/sysv/linux/sh/pwrite.c (__libc_pwrite): Likewise.
* sysdeps/unix/sysv/linux/sh/pwrite64.c (__libc_pwrite64): Likewise.
* sysdeps/unix/sysv/linux/sigsuspend.c (__sigsuspend): Likewise.
* sysdeps/unix/sysv/linux/sigtimedwait.c (__sigtimedwait): Likewise.
* sysdeps/unix/sysv/linux/sigwaitinfo.c (__sigwaitinfo): Likewise.
* sysdeps/unix/sysv/linux/sparc/sparc64/msgrcv.c (__libc_msgrcv):
Likewise.
* sysdeps/unix/sysv/linux/sync_file_range.c (sync_file_range):
Likewise.
* sysdeps/unix/sysv/linux/tcdrain.c (__libc_tcdrain): Likewise.
* sysdeps/unix/sysv/linux/timer_routines.c (timer_helper_thread):
Likewise.
* sysdeps/unix/sysv/linux/wait.c (__libc_wait): Likewise.
* sysdeps/unix/sysv/linux/waitid.c (__waitid): Likewise.
* sysdeps/unix/sysv/linux/waitpid.c (__libc_waitpid): Likewise.
* sysdeps/unix/sysv/linux/wordsize-64/fallocate.c (fallocate):
Likewise.
* sysdeps/unix/sysv/linux/wordsize-64/preadv.c (preadv): Likewise.
* sysdeps/unix/sysv/linux/wordsize-64/pwritev.c (pwritev): Likewise.
* sysdeps/unix/sysv/linux/writev.c (__libc_writev): Likewise.
* sysdeps/unix/sysv/linux/x86_64/recv.c (__libc_recv): Likewise.
* sysdeps/unix/sysv/linux/x86_64/send.c (__libc_send): Likewise.
2014-09-28 11:46:23 +00:00
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return SYSCALL_CANCEL (openat, fd, file, oflag, mode);
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2006-02-12 21:41:44 +00:00
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}
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2017-06-20 18:46:28 +00:00
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weak_alias (__libc_openat, __openat)
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libc_hidden_weak (__openat)
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weak_alias (__libc_openat, openat)
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#endif
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