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3abf3bd4ed
This closes one remaining race condition related to bug 12889: if
the thread already exited on the kernel side, returning ESRCH
is not correct because that error is reserved for the thread IDs
(pthread_t values) whose lifetime has ended. In case of a
kernel-side exit and a valid thread ID, no signal needs to be sent
and cancellation does not have an effect, so just return 0.
sysdeps/pthread/tst-kill4.c triggers undefined behavior and is
removed with this commit.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
(cherry picked from commit 8af8456004)
79 lines
2.7 KiB
C
79 lines
2.7 KiB
C
/* Send a signal to a specific pthread. Stub version.
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Copyright (C) 2014-2021 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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<https://www.gnu.org/licenses/>. */
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#include <unistd.h>
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#include <pthreadP.h>
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#include <shlib-compat.h>
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int
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__pthread_kill_internal (pthread_t threadid, int signo)
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{
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pid_t tid;
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struct pthread *pd = (struct pthread *) threadid;
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if (pd == THREAD_SELF)
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/* It is a special case to handle raise() implementation after a vfork
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call (which does not update the PD tid field). */
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tid = INLINE_SYSCALL_CALL (gettid);
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else
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/* Force load of pd->tid into local variable or register. Otherwise
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if a thread exits between ESRCH test and tgkill, we might return
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EINVAL, because pd->tid would be cleared by the kernel. */
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tid = atomic_forced_read (pd->tid);
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int val;
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if (__glibc_likely (tid > 0))
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{
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pid_t pid = __getpid ();
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val = INTERNAL_SYSCALL_CALL (tgkill, pid, tid, signo);
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val = (INTERNAL_SYSCALL_ERROR_P (val)
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? INTERNAL_SYSCALL_ERRNO (val) : 0);
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}
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else
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/* The kernel reports that the thread has exited. POSIX specifies
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the ESRCH error only for the case when the lifetime of a thread
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ID has ended, but calling pthread_kill on such a thread ID is
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undefined in glibc. Therefore, do not treat kernel thread exit
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as an error. */
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val = 0;
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return val;
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}
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int
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__pthread_kill (pthread_t threadid, int signo)
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{
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/* Disallow sending the signal we use for cancellation, timers,
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for the setxid implementation. */
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if (__is_internal_signal (signo))
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return EINVAL;
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return __pthread_kill_internal (threadid, signo);
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}
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/* Some architectures (for instance arm) might pull raise through libgcc, so
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avoid the symbol version if it ends up being used on ld.so. */
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#if !IS_IN(rtld)
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libc_hidden_def (__pthread_kill)
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versioned_symbol (libc, __pthread_kill, pthread_kill, GLIBC_2_34);
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# if OTHER_SHLIB_COMPAT (libpthread, GLIBC_2_0, GLIBC_2_34)
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compat_symbol (libc, __pthread_kill, pthread_kill, GLIBC_2_0);
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# endif
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#endif
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