Filter out NPTL internal signals (BZ #22391)
This patch filters out the internal NPTL signals (SIGCANCEL/SIGTIMER and
SIGSETXID) from signal functions. GLIBC on Linux requires both signals to
proper implement pthread cancellation, posix timers, and set*id posix
thread synchronization.
And not filtering out the internal signal is troublesome:
- A conformant program on a architecture that does not filter out the
signals might inadvertently disable pthread asynchronous cancellation,
set*id synchronization or posix timers.
- It might also to security issues if SIGSETXID is masked and set*id
functions are called (some threads might have effective user or group
id different from the rest).
The changes are basically:
- Change __is_internal_signal to bool and used on all signal function
that has a signal number as input. Also for signal function which accepts
signals sets (sigset_t) it assumes that canonical function were used to
add/remove signals which lead to some input simplification.
- Fix tst-sigset.c to avoid check for SIGCANCEL/SIGTIMER and SIGSETXID.
It is rewritten to check each signal indidually and to check realtime
signals using canonical macros.
- Add generic __clear_internal_signals and __is_internal_signal
version since both symbols are used on generic implementations.
- Remove superflous sysdeps/nptl/sigfillset.c.
- Remove superflous SIGTIMER handling on Linux __is_internal_signal
since it is the same of SIGCANCEL.
- Remove dangling define and obvious comment on nptl/sigaction.c.
Checked on x86_64-linux-gnu.
[BZ #22391]
* nptl/sigaction.c (__sigaction): Use __is_internal_signal to
check for internal nptl signals.
* nptl/sigaction.c (__sigaction): Likewise.
* signal/sigaddset.c (sigaddset): Likewise.
* signal/sigdelset.c (sigdelset): Likewise.
* sysdeps/posix/signal.c (__bsd_signal): Likewise.
* sysdeps/posix/sigset.c (sigset): Call and check sigaddset return
value.
* signal/sigfillset.c (sigfillset): User __clear_internal_signals
to filter out internal nptl signals.
* signal/tst-sigset.c (do_test): Check ech signal indidually and
also check realtime signals using standard macros.
* sysdeps/generic/internal-signals.h (__clear_internal_signals,
__is_internal_signal, __libc_signal_block_all,
__libc_signal_block_app, __libc_signal_restore_set): New functions.
* sysdeps/nptl/sigfillset.c: Remove file.
* sysdeps/unix/sysv/linux/internal-signals.h (__is_internal_signal):
Change return to bool.
(__clear_internal_signals): Remove SIGTIMER clean since it is
equal to SIGCANEL on Linux.
* sysdeps/unix/sysv/linux/sigtimedwait.c (__sigtimedwait): Assume
signal set was constructed using standard functions.
Reported-by: Yury Norov <ynorov@caviumnetworks.com>
This commit is contained in:
Adhemerval Zanella
parent
511ed56f2e
commit
d2dc5467c6
26
ChangeLog
26
ChangeLog
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@ -1,3 +1,29 @@
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2018-04-03 Adhemerval Zanella <adhemerval.zanella@linaro.org>
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[BZ #22391]
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* nptl/sigaction.c (__sigaction): Use __is_internal_signal to
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check for internal nptl signals.
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* nptl/sigaction.c (__sigaction): Likewise.
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* signal/sigaddset.c (sigaddset): Likewise.
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* signal/sigdelset.c (sigdelset): Likewise.
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* sysdeps/posix/signal.c (__bsd_signal): Likewise.
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* sysdeps/posix/sigset.c (sigset): Call and check sigaddset return
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value.
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* signal/sigfillset.c (sigfillset): User __clear_internal_signals
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to filter out internal nptl signals.
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* signal/tst-sigset.c (do_test): Check ech signal indidually and
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also check realtime signals using standard macros.
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* sysdeps/generic/internal-signals.h (__clear_internal_signals,
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__is_internal_signal, __libc_signal_block_all,
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__libc_signal_block_app, __libc_signal_restore_set): New functions.
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* sysdeps/nptl/sigfillset.c: Remove file.
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* sysdeps/unix/sysv/linux/internal-signals.h (__is_internal_signal):
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Change return to bool.
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(__clear_internal_signals): Remove SIGTIMER clean since it is
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equal to SIGCANEL on Linux.
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* sysdeps/unix/sysv/linux/sigtimedwait.c (__sigtimedwait): Assume
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signal set was constructed using standard functions.
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2018-04-03 Samuel Thibault <samuel.thibault@ens-lyon.org>
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* sysdeps/mach/hurd/if_index.c (__if_nametoindex): Always end
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@ -16,22 +16,12 @@
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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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/* This is no complete implementation. The file is meant to be
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included in the real implementation to provide the wrapper around
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__libc_sigaction. */
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#include <nptl/pthreadP.h>
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/* We use the libc implementation but we tell it to not allow
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SIGCANCEL or SIGTIMER to be handled. */
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#define LIBC_SIGACTION 1
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#include <internal-signals.h>
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int
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__sigaction (int sig, const struct sigaction *act, struct sigaction *oact)
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{
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if (__glibc_unlikely (sig == SIGCANCEL || sig == SIGSETXID))
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if (sig <= 0 || sig >= NSIG || __is_internal_signal (sig))
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{
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__set_errno (EINVAL);
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return -1;
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@ -24,7 +24,7 @@
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int
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__sigaction (int sig, const struct sigaction *act, struct sigaction *oact)
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{
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if (sig <= 0 || sig >= NSIG)
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if (sig <= 0 || sig >= NSIG || __is_internal_signal (sig))
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{
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__set_errno (EINVAL);
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return -1;
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@ -17,13 +17,14 @@
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#include <errno.h>
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#include <signal.h>
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#include <sigsetops.h>
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#include <internal-signals.h>
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/* Add SIGNO to SET. */
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int
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sigaddset (sigset_t *set, int signo)
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{
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if (set == NULL || signo <= 0 || signo >= NSIG)
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if (set == NULL || signo <= 0 || signo >= NSIG
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|| __is_internal_signal (signo))
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{
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__set_errno (EINVAL);
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return -1;
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@ -17,13 +17,14 @@
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#include <errno.h>
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#include <signal.h>
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#include <sigsetops.h>
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#include <internal-signals.h>
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/* Add SIGNO to SET. */
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int
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sigdelset (sigset_t *set, int signo)
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{
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if (set == NULL || signo <= 0 || signo >= NSIG)
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if (set == NULL || signo <= 0 || signo >= NSIG
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|| __is_internal_signal (signo))
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{
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__set_errno (EINVAL);
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return -1;
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@ -18,6 +18,7 @@
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#include <errno.h>
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#include <signal.h>
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#include <string.h>
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#include <internal-signals.h>
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/* Set all signals in SET. */
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int
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@ -31,14 +32,7 @@ sigfillset (sigset_t *set)
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memset (set, 0xff, sizeof (sigset_t));
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/* If the implementation uses a cancellation signal don't set the bit. */
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#ifdef SIGCANCEL
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__sigdelset (set, SIGCANCEL);
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#endif
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/* Likewise for the signal to implement setxid. */
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#ifdef SIGSETXID
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__sigdelset (set, SIGSETXID);
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#endif
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__clear_internal_signals (set);
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return 0;
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}
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@ -1,43 +1,85 @@
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/* Test sig*set functions. */
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#include <signal.h>
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#include <stdio.h>
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#define TEST_FUNCTION do_test ()
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#include <support/check.h>
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static int
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do_test (void)
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{
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int result = 0;
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int sig = -1;
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#define TRY(call) \
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if (call) \
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{ \
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printf ("%s (sig = %d): %m\n", #call, sig); \
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result = 1; \
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} \
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else
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sigset_t set;
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TRY (sigemptyset (&set) != 0);
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TEST_VERIFY (sigemptyset (&set) == 0);
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#ifdef SIGRTMAX
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int max_sig = SIGRTMAX;
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#else
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int max_sig = NSIG - 1;
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#define VERIFY(set, sig) \
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TEST_VERIFY (sigismember (&set, sig) == 0); \
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TEST_VERIFY (sigaddset (&set, sig) == 0); \
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TEST_VERIFY (sigismember (&set, sig) != 0); \
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TEST_VERIFY (sigdelset (&set, sig) == 0); \
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TEST_VERIFY (sigismember (&set, sig) == 0)
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/* ISO C99 signals. */
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VERIFY (set, SIGINT);
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VERIFY (set, SIGILL);
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VERIFY (set, SIGABRT);
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VERIFY (set, SIGFPE);
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VERIFY (set, SIGSEGV);
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VERIFY (set, SIGTERM);
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/* Historical signals specified by POSIX. */
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VERIFY (set, SIGHUP);
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VERIFY (set, SIGQUIT);
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VERIFY (set, SIGTRAP);
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VERIFY (set, SIGKILL);
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VERIFY (set, SIGBUS);
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VERIFY (set, SIGSYS);
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VERIFY (set, SIGPIPE);
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VERIFY (set, SIGALRM);
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/* New(er) POSIX signals (1003.1-2008, 1003.1-2013). */
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VERIFY (set, SIGURG);
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VERIFY (set, SIGSTOP);
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VERIFY (set, SIGTSTP);
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VERIFY (set, SIGCONT);
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VERIFY (set, SIGCHLD);
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VERIFY (set, SIGTTIN);
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VERIFY (set, SIGTTOU);
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VERIFY (set, SIGPOLL);
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VERIFY (set, SIGXCPU);
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VERIFY (set, SIGXFSZ);
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VERIFY (set, SIGVTALRM);
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VERIFY (set, SIGPROF);
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VERIFY (set, SIGUSR1);
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VERIFY (set, SIGUSR2);
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/* Nonstandard signals found in all modern POSIX systems
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(including both BSD and Linux). */
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VERIFY (set, SIGWINCH);
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/* Arch-specific signals. */
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#ifdef SIGEMT
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VERIFY (set, SIGEMT);
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#endif
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#ifdef SIGLOST
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VERIFY (set, SIGLOST);
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#endif
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#ifdef SIGINFO
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VERIFY (set, SIGINFO);
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#endif
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#ifdef SIGSTKFLT
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VERIFY (set, SIGSTKFLT);
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#endif
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#ifdef SIGPWR
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VERIFY (set, SIGPWR);
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#endif
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for (sig = 1; sig <= max_sig; ++sig)
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/* Read-time signals (POSIX.1b real-time extensions). If they are
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supported SIGRTMAX value is greater than SIGRTMIN. */
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for (int rtsig = SIGRTMIN; rtsig <= SIGRTMAX; rtsig++)
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{
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TRY (sigismember (&set, sig) != 0);
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TRY (sigaddset (&set, sig) != 0);
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TRY (sigismember (&set, sig) == 0);
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TRY (sigdelset (&set, sig) != 0);
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TRY (sigismember (&set, sig) != 0);
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VERIFY (set, rtsig);
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}
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return result;
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return 0;
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}
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#include "../test-skeleton.c"
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#include <support/test-driver.c>
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@ -15,3 +15,39 @@
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You should have received a copy of the GNU Lesser General Public
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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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#ifndef __INTERNAL_SIGNALS_H
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# define __INTERNAL_SIGNALS_H
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static inline bool
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__is_internal_signal (int sig)
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{
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return false;
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}
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static inline void
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__clear_internal_signals (sigset_t *set)
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{
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}
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static inline int
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__libc_signal_block_all (sigset_t *set)
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{
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return 0;
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}
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static inline int
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__libc_signal_block_app (sigset_t *set)
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{
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return 0;
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}
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/* Restore current process signal mask. */
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static inline int
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__libc_signal_restore_set (const sigset_t *set)
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{
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return 0;
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}
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#endif /* __INTERNAL_SIGNALS_H */
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@ -1,20 +0,0 @@
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/* Copyright (C) 2003-2018 Free Software Foundation, Inc.
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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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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#include <nptl/pthreadP.h>
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#include <signal/sigfillset.c>
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@ -18,8 +18,8 @@
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#include <errno.h>
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#include <signal.h>
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#include <string.h> /* For the real memset prototype. */
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#include <sigsetops.h>
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#include <internal-signals.h>
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sigset_t _sigintr attribute_hidden; /* Set by siginterrupt. */
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@ -31,7 +31,8 @@ __bsd_signal (int sig, __sighandler_t handler)
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struct sigaction act, oact;
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/* Check signal extents to protect __sigismember. */
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if (handler == SIG_ERR || sig < 1 || sig >= NSIG)
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if (handler == SIG_ERR || sig < 1 || sig >= NSIG
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|| __is_internal_signal (sig))
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{
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__set_errno (EINVAL);
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return SIG_ERR;
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@ -31,15 +31,9 @@ sigset (int sig, __sighandler_t disp)
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sigset_t set;
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sigset_t oset;
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/* Check signal extents to protect __sigismember. */
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if (disp == SIG_ERR || sig < 1 || sig >= NSIG)
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{
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__set_errno (EINVAL);
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return SIG_ERR;
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}
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__sigemptyset (&set);
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__sigaddset (&set, sig);
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if (sigaddset (&set, sig) < 0)
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return SIG_ERR;
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if (disp == SIG_HOLD)
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{
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@ -21,6 +21,8 @@
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#include <signal.h>
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#include <sigsetops.h>
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#include <stdbool.h>
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#include <sysdep.h>
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/* The signal used for asynchronous cancelation. */
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#define SIGCANCEL __SIGRTMIN
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@ -37,7 +39,7 @@
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/* Return is sig is used internally. */
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static inline int
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static inline bool
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__is_internal_signal (int sig)
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{
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return (sig == SIGCANCEL) || (sig == SIGSETXID);
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@ -24,21 +24,8 @@ int
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__sigtimedwait (const sigset_t *set, siginfo_t *info,
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const struct timespec *timeout)
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{
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sigset_t tmpset;
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if (set != NULL
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&& (__builtin_expect (__sigismember (set, SIGCANCEL), 0)
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|| __builtin_expect (__sigismember (set, SIGSETXID), 0)))
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{
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/* Create a temporary mask without the bit for SIGCANCEL set. */
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// We are not copying more than we have to.
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memcpy (&tmpset, set, _NSIG / 8);
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__sigdelset (&tmpset, SIGCANCEL);
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__sigdelset (&tmpset, SIGSETXID);
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set = &tmpset;
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}
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/* XXX The size argument hopefully will have to be changed to the
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real size of the user-level sigset_t. */
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/* XXX The size argument hopefully will have to be changed to the
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real size of the user-level sigset_t. */
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int result = SYSCALL_CANCEL (rt_sigtimedwait, set, info, timeout, _NSIG / 8);
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/* The kernel generates a SI_TKILL code in si_code in case tkill is
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