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Simplify Linux sig{timed}wait{info} implementations

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This patch simplifies sig{timed}wait{info} by:

  - Assuming __NR_rt_sigtimedwait existence on all architectures due minimum
    kernel version requirement (it pre-dates Linux git inclusion for Linux
    2.6.12).

  - Call __sigtimedwait on both sigwait and sigwaitinfo.

  - Now that sigwait is based on an internal sigtimedwait call and it is
    present of both libc.so and libpthread.so we need to add an external
    private definition of __sigtimedwait for libpthread.so call.

Checked on x86_64-linux-gnu.

	* sysdeps/unix/sysv/linux/Versions (libc) [GLIBC_PRIVATE]: Add
	__sigtimedwait.
	* sysdeps/unix/sysv/linux/sigtimedwait.c: Simplify includes and
	assume __NR_rt_sigtimedwait.
	* sysdeps/unix/sysv/linux/sigwait.c (__sigwait): Call __sigtimedwait
	and add LIBC_CANCEL_HANDLED for cancellation marking.
	* sysdeps/unix/sysv/linux/sigwaitinfo.c (__sigwaitinfo): Likewise.

Signed-off-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Reviewed-by: Zack Weinberg <zackw@panix.com>
This commit is contained in:
Adhemerval Zanella
2017-11-01 11:49:05 -02:00
parent a1a638dda9
commit 8b0e795aaa
5 changed files with 21 additions and 118 deletions
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8
ChangeLog
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@ -1,5 +1,13 @@
2017-11-06 Adhemerval Zanella <adhemerval.zanella@linaro.org>
* sysdeps/unix/sysv/linux/Versions (libc) [GLIBC_PRIVATE]: Add
__sigtimedwait.
* sysdeps/unix/sysv/linux/sigtimedwait.c: Simplify includes and
assume __NR_rt_sigtimedwait.
* sysdeps/unix/sysv/linux/sigwait.c (__sigwait): Call __sigtimedwait
and add LIBC_CANCEL_HANDLED for cancellation marking.
* sysdeps/unix/sysv/linux/sigwaitinfo.c (__sigwaitinfo): Likewise.
* sysdeps/arm/armv7/multiarch/Makefile [$(subdir) = string]
(sysdeps_routines): Add memchr_noneon.
* sysdeps/arm/armv7/multiarch/ifunc-memchr.h: New file.

1
sysdeps/unix/sysv/linux/Versions
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@ -172,6 +172,7 @@ libc {
__open_nocancel;
__read_nocancel;
__close_nocancel;
__sigtimedwait;
# functions used by nscd
__netlink_assert_response;
}

8
sysdeps/unix/sysv/linux/sigtimedwait.c
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@ -18,12 +18,7 @@
#include <errno.h>
#include <signal.h>
#include <string.h>
#include <nptl/pthreadP.h>
#include <sysdep-cancel.h>
#include <sys/syscall.h>
#ifdef __NR_rt_sigtimedwait
int
__sigtimedwait (const sigset_t *set, siginfo_t *info,
@ -57,6 +52,3 @@ __sigtimedwait (const sigset_t *set, siginfo_t *info,
}
libc_hidden_def (__sigtimedwait)
weak_alias (__sigtimedwait, sigtimedwait)
#else
# include <signal/sigtimedwait.c>
#endif

81
sysdeps/unix/sysv/linux/sigwait.c
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@ -15,86 +15,21 @@
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include <errno.h>
#include <signal.h>
#define __need_NULL
#include <stddef.h>
#include <string.h>
#include <nptl/pthreadP.h>
#include <sysdep-cancel.h>
#include <sys/syscall.h>
#ifdef __NR_rt_sigtimedwait
/* Return any pending signal or wait for one for the given time. */
static int
do_sigwait (const sigset_t *set, int *sig)
{
int ret;
sigset_t tmpset;
if (set != NULL
&& (__builtin_expect (__sigismember (set, SIGCANCEL), 0)
|| __builtin_expect (__sigismember (set, SIGSETXID), 0)))
{
/* Create a temporary mask without the bit for SIGCANCEL set. */
// We are not copying more than we have to.
memcpy (&tmpset, set, _NSIG / 8);
__sigdelset (&tmpset, SIGCANCEL);
__sigdelset (&tmpset, SIGSETXID);
set = &tmpset;
}
/* XXX The size argument hopefully will have to be changed to the
real size of the user-level sigset_t. */
#ifdef INTERNAL_SYSCALL
INTERNAL_SYSCALL_DECL (err);
do
ret = INTERNAL_SYSCALL (rt_sigtimedwait, err, 4, set,
NULL, NULL, _NSIG / 8);
while (INTERNAL_SYSCALL_ERROR_P (ret, err)
&& INTERNAL_SYSCALL_ERRNO (ret, err) == EINTR);
if (! INTERNAL_SYSCALL_ERROR_P (ret, err))
{
*sig = ret;
ret = 0;
}
else
ret = INTERNAL_SYSCALL_ERRNO (ret, err);
#else
do
ret = INLINE_SYSCALL (rt_sigtimedwait, 4, set, NULL, NULL, _NSIG / 8);
while (ret == -1 && errno == EINTR);
if (ret != -1)
{
*sig = ret;
ret = 0;
}
else
ret = errno;
#endif
return ret;
}
int
__sigwait (const sigset_t *set, int *sig)
{
if (SINGLE_THREAD_P)
return do_sigwait (set, sig);
int oldtype = LIBC_CANCEL_ASYNC ();
int result = do_sigwait (set, sig);
LIBC_CANCEL_RESET (oldtype);
return result;
siginfo_t si;
if (__sigtimedwait (set, &si, 0) < 0)
return -1;
*sig = si.si_signo;
return 0;
}
libc_hidden_def (__sigwait)
weak_alias (__sigwait, sigwait)
#else
# include <sysdeps/posix/sigwait.c>
#endif
strong_alias (__sigwait, __libc_sigwait)
/* __sigtimedwait handles cancellation. */
LIBC_CANCEL_HANDLED ();

41
sysdeps/unix/sysv/linux/sigwaitinfo.c
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@ -15,52 +15,19 @@
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include <errno.h>
#include <signal.h>
#define __need_NULL
#include <stddef.h>
#include <string.h>
#include <nptl/pthreadP.h>
#include <sysdep-cancel.h>
#include <sys/syscall.h>
#ifdef __NR_rt_sigtimedwait
/* Return any pending signal or wait for one for the given time. */
int
__sigwaitinfo (const sigset_t *set, siginfo_t *info)
{
sigset_t tmpset;
if (set != NULL
&& (__builtin_expect (__sigismember (set, SIGCANCEL), 0)
|| __builtin_expect (__sigismember (set, SIGSETXID), 0)))
{
/* Create a temporary mask without the bit for SIGCANCEL set. */
// We are not copying more than we have to.
memcpy (&tmpset, set, _NSIG / 8);
__sigdelset (&tmpset, SIGCANCEL);
__sigdelset (&tmpset, SIGSETXID);
set = &tmpset;
}
/* XXX The size argument hopefully will have to be changed to the
real size of the user-level sigset_t. */
int result = SYSCALL_CANCEL (rt_sigtimedwait, set, info, NULL, _NSIG / 8);
/* The kernel generates a SI_TKILL code in si_code in case tkill is
used. tkill is transparently used in raise(). Since having
SI_TKILL as a code is useful in general we fold the results
here. */
if (result != -1 && info != NULL && info->si_code == SI_TKILL)
info->si_code = SI_USER;
return result;
return __sigtimedwait (set, info, 0);
}
libc_hidden_def (__sigwaitinfo)
weak_alias (__sigwaitinfo, sigwaitinfo)
#else
# include <signal/sigwaitinfo.c>
#endif
strong_alias (__sigwaitinfo, __libc_sigwaitinfo)
/* __sigtimedwait handles cancellation. */
LIBC_CANCEL_HANDLED ();