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mirror of https://sourceware.org/git/glibc.git synced 2025-10-12 19:04:54 +03:00

Linux: Add the pthread_gettid_np function (bug 27880)

Current Bionic has this function, with enhanced error checking
(the undefined case terminates the process).

Reviewed-by: Joseph Myers <josmyers@redhat.com>
This commit is contained in:
Florian Weimer
2025-03-12 10:16:31 +01:00
parent d604f9c500
commit 74d463c50b
39 changed files with 171 additions and 0 deletions

2
NEWS
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@@ -16,6 +16,8 @@ Major new features:
- Power and absolute-value functions: rsqrt.
* On Linux, the pthread_gettid_np function has been added.
Deprecated and removed features, and other changes affecting compatibility:
[Add deprecations, removals and changes affecting compatibility here]

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@@ -239,6 +239,24 @@ especially regarding reuse of the IDs of threads which have exited.
This function is specific to Linux.
@end deftypefun
@deftypefun pid_t pthread_gettid_np (pthread_t @var{thread})
@standards{Linux, pthread.h}
@safety{@prelim{}@mtsafe{}@assafe{}@acsafe{}}
This function returns the same value that @code{gettid} would return if
executed on the running thread @var{thread}.
If @var{thread} is no longer running but it is joinable, it is
unspecified whether this function returns @minus{}1, or if it returns
the thread ID of the thread while it was running. If @var{thread} is
not running and is not joinable, the behavior is undefined.
@strong{Portability Note:} Linux thread IDs can be reused rather quickly,
so this function differs from the @code{pthread_getunique_np} function
found on other systems.
This function is specific to Linux.
@end deftypefun
@node Creating a Process
@section Creating a Process

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@@ -124,6 +124,7 @@ routines = \
pthread_getname \
pthread_getschedparam \
pthread_getspecific \
pthread_gettid_np \
pthread_join \
pthread_join_common \
pthread_key_create \
@@ -326,6 +327,7 @@ tests = \
tst-pthread-timedlock-lockloop \
tst-pthread_exit-nothreads \
tst-pthread_exit-nothreads-static \
tst-pthread_gettid_np \
tst-robust-fork \
tst-robustpi1 \
tst-robustpi2 \

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@@ -378,6 +378,9 @@ libc {
tss_get;
tss_set;
}
GLIBC_2.42 {
pthread_gettid_np;
}
GLIBC_PRIVATE {
__libc_alloca_cutoff;
__lll_lock_wake_private;

30
nptl/pthread_gettid_np.c Normal file
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@@ -0,0 +1,30 @@
/* Get the Linux TID from a pthread_t handle.
Copyright (C) 2025 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; see the file COPYING.LIB. If
not, see <https://www.gnu.org/licenses/>. */
#include <errno.h>
#include <pthreadP.h>
pid_t
pthread_gettid_np (pthread_t threadid)
{
/* The kernel may concurrently set this field. */
pid_t tid = atomic_load_relaxed (&((struct pthread *) threadid)->tid);
if (tid <= 0)
return -1;
return tid;
}

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@@ -0,0 +1,79 @@
/* Test for pthread_gettid_np.
Copyright (C) 2025 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; see the file COPYING.LIB. If
not, see <https://www.gnu.org/licenses/>. */
#include <errno.h>
#include <pthread.h>
#include <sched.h>
#include <signal.h>
#include <support/check.h>
#include <support/xthread.h>
#include <unistd.h>
static pthread_barrier_t barrier;
static pid_t thread_tid;
static void *
thread_func (void *ignored)
{
thread_tid = gettid ();
TEST_VERIFY (thread_tid != getpid ());
TEST_COMPARE (thread_tid, pthread_gettid_np (pthread_self ()));
xpthread_barrier_wait (&barrier);
/* The main thread calls pthread_gettid_np here. */
xpthread_barrier_wait (&barrier);
return NULL;
}
static int
do_test (void)
{
TEST_COMPARE (pthread_gettid_np (pthread_self ()), getpid ());
TEST_COMPARE (pthread_gettid_np (pthread_self ()), gettid ());
xpthread_barrier_init (&barrier, NULL, 2);
pthread_t thr = xpthread_create (NULL, thread_func, NULL);
xpthread_barrier_wait (&barrier);
TEST_COMPARE (thread_tid, pthread_gettid_np (thr));
xpthread_barrier_wait (&barrier);
while (true)
{
/* Check if the kernel thread is still running. */
if (tgkill (getpid (), thread_tid, 0))
{
TEST_COMPARE (errno, ESRCH);
break;
}
pid_t tid = pthread_gettid_np (thr);
if (tid != thread_tid)
{
TEST_COMPARE (tid, -1);
break;
}
TEST_COMPARE (sched_yield (), 0);
}
TEST_VERIFY (xpthread_join (thr) == NULL);
return 0;
}
#include <support/test-driver.c>

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@@ -1317,6 +1317,11 @@ extern int pthread_getcpuclockid (pthread_t __thread_id,
__THROW __nonnull ((2));
#endif
#ifdef __USE_GNU
/* Return the Linux TID for THREAD_ID. Returns -1 on failure. */
extern pid_t pthread_gettid_np (pthread_t __thread_id);
#endif
/* Install handlers to be called when a new process is created with FORK.
The PREPARE handler is called in the parent process just before performing

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@@ -2750,3 +2750,4 @@ GLIBC_2.39 stdc_trailing_zeros_ull F
GLIBC_2.39 stdc_trailing_zeros_us F
GLIBC_2.41 sched_getattr F
GLIBC_2.41 sched_setattr F
GLIBC_2.42 pthread_gettid_np F

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@@ -3097,6 +3097,7 @@ GLIBC_2.4 wprintf F
GLIBC_2.4 wscanf F
GLIBC_2.41 sched_getattr F
GLIBC_2.41 sched_setattr F
GLIBC_2.42 pthread_gettid_np F
GLIBC_2.5 __readlinkat_chk F
GLIBC_2.5 inet6_opt_append F
GLIBC_2.5 inet6_opt_find F

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@@ -2511,3 +2511,4 @@ GLIBC_2.39 stdc_trailing_zeros_ull F
GLIBC_2.39 stdc_trailing_zeros_us F
GLIBC_2.41 sched_getattr F
GLIBC_2.41 sched_setattr F
GLIBC_2.42 pthread_gettid_np F

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@@ -2803,6 +2803,7 @@ GLIBC_2.4 xprt_register F
GLIBC_2.4 xprt_unregister F
GLIBC_2.41 sched_getattr F
GLIBC_2.41 sched_setattr F
GLIBC_2.42 pthread_gettid_np F
GLIBC_2.5 __readlinkat_chk F
GLIBC_2.5 inet6_opt_append F
GLIBC_2.5 inet6_opt_find F

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@@ -2800,6 +2800,7 @@ GLIBC_2.4 xprt_register F
GLIBC_2.4 xprt_unregister F
GLIBC_2.41 sched_getattr F
GLIBC_2.41 sched_setattr F
GLIBC_2.42 pthread_gettid_np F
GLIBC_2.5 __readlinkat_chk F
GLIBC_2.5 inet6_opt_append F
GLIBC_2.5 inet6_opt_find F

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@@ -2787,3 +2787,4 @@ GLIBC_2.39 stdc_trailing_zeros_ull F
GLIBC_2.39 stdc_trailing_zeros_us F
GLIBC_2.41 sched_getattr F
GLIBC_2.41 sched_setattr F
GLIBC_2.42 pthread_gettid_np F

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@@ -2824,6 +2824,7 @@ GLIBC_2.4 unshare F
GLIBC_2.41 cacheflush F
GLIBC_2.41 sched_getattr F
GLIBC_2.41 sched_setattr F
GLIBC_2.42 pthread_gettid_np F
GLIBC_2.5 __readlinkat_chk F
GLIBC_2.5 inet6_opt_append F
GLIBC_2.5 inet6_opt_find F

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@@ -3007,6 +3007,7 @@ GLIBC_2.4 unlinkat F
GLIBC_2.4 unshare F
GLIBC_2.41 sched_getattr F
GLIBC_2.41 sched_setattr F
GLIBC_2.42 pthread_gettid_np F
GLIBC_2.5 __readlinkat_chk F
GLIBC_2.5 inet6_opt_append F
GLIBC_2.5 inet6_opt_find F

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@@ -2271,3 +2271,4 @@ GLIBC_2.39 stdc_trailing_zeros_ull F
GLIBC_2.39 stdc_trailing_zeros_us F
GLIBC_2.41 sched_getattr F
GLIBC_2.41 sched_setattr F
GLIBC_2.42 pthread_gettid_np F

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@@ -2783,6 +2783,7 @@ GLIBC_2.4 xprt_register F
GLIBC_2.4 xprt_unregister F
GLIBC_2.41 sched_getattr F
GLIBC_2.41 sched_setattr F
GLIBC_2.42 pthread_gettid_np F
GLIBC_2.5 __readlinkat_chk F
GLIBC_2.5 inet6_opt_append F
GLIBC_2.5 inet6_opt_find F

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@@ -2950,6 +2950,7 @@ GLIBC_2.4 unlinkat F
GLIBC_2.4 unshare F
GLIBC_2.41 sched_getattr F
GLIBC_2.41 sched_setattr F
GLIBC_2.42 pthread_gettid_np F
GLIBC_2.5 __readlinkat_chk F
GLIBC_2.5 inet6_opt_append F
GLIBC_2.5 inet6_opt_find F

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@@ -2836,3 +2836,4 @@ GLIBC_2.39 stdc_trailing_zeros_ull F
GLIBC_2.39 stdc_trailing_zeros_us F
GLIBC_2.41 sched_getattr F
GLIBC_2.41 sched_setattr F
GLIBC_2.42 pthread_gettid_np F

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@@ -2833,3 +2833,4 @@ GLIBC_2.39 stdc_trailing_zeros_ull F
GLIBC_2.39 stdc_trailing_zeros_us F
GLIBC_2.41 sched_getattr F
GLIBC_2.41 sched_setattr F
GLIBC_2.42 pthread_gettid_np F

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@@ -2911,6 +2911,7 @@ GLIBC_2.4 unlinkat F
GLIBC_2.4 unshare F
GLIBC_2.41 sched_getattr F
GLIBC_2.41 sched_setattr F
GLIBC_2.42 pthread_gettid_np F
GLIBC_2.5 __readlinkat_chk F
GLIBC_2.5 inet6_opt_append F
GLIBC_2.5 inet6_opt_find F

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@@ -2909,6 +2909,7 @@ GLIBC_2.4 unlinkat F
GLIBC_2.4 unshare F
GLIBC_2.41 sched_getattr F
GLIBC_2.41 sched_setattr F
GLIBC_2.42 pthread_gettid_np F
GLIBC_2.5 __readlinkat_chk F
GLIBC_2.5 inet6_opt_append F
GLIBC_2.5 inet6_opt_find F

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@@ -2917,6 +2917,7 @@ GLIBC_2.4 unlinkat F
GLIBC_2.4 unshare F
GLIBC_2.41 sched_getattr F
GLIBC_2.41 sched_setattr F
GLIBC_2.42 pthread_gettid_np F
GLIBC_2.5 __readlinkat_chk F
GLIBC_2.5 inet6_opt_append F
GLIBC_2.5 inet6_opt_find F

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@@ -2819,6 +2819,7 @@ GLIBC_2.4 unlinkat F
GLIBC_2.4 unshare F
GLIBC_2.41 sched_getattr F
GLIBC_2.41 sched_setattr F
GLIBC_2.42 pthread_gettid_np F
GLIBC_2.5 __readlinkat_chk F
GLIBC_2.5 inet6_opt_append F
GLIBC_2.5 inet6_opt_find F

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@@ -2261,3 +2261,4 @@ GLIBC_2.40 setcontext F
GLIBC_2.40 swapcontext F
GLIBC_2.41 sched_getattr F
GLIBC_2.41 sched_setattr F
GLIBC_2.42 pthread_gettid_np F

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@@ -3140,6 +3140,7 @@ GLIBC_2.4 wprintf F
GLIBC_2.4 wscanf F
GLIBC_2.41 sched_getattr F
GLIBC_2.41 sched_setattr F
GLIBC_2.42 pthread_gettid_np F
GLIBC_2.5 __readlinkat_chk F
GLIBC_2.5 inet6_opt_append F
GLIBC_2.5 inet6_opt_find F

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@@ -3185,6 +3185,7 @@ GLIBC_2.4 wprintf F
GLIBC_2.4 wscanf F
GLIBC_2.41 sched_getattr F
GLIBC_2.41 sched_setattr F
GLIBC_2.42 pthread_gettid_np F
GLIBC_2.5 __readlinkat_chk F
GLIBC_2.5 inet6_opt_append F
GLIBC_2.5 inet6_opt_find F

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@@ -2894,6 +2894,7 @@ GLIBC_2.4 wprintf F
GLIBC_2.4 wscanf F
GLIBC_2.41 sched_getattr F
GLIBC_2.41 sched_setattr F
GLIBC_2.42 pthread_gettid_np F
GLIBC_2.5 __readlinkat_chk F
GLIBC_2.5 inet6_opt_append F
GLIBC_2.5 inet6_opt_find F

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@@ -2970,3 +2970,4 @@ GLIBC_2.39 stdc_trailing_zeros_ull F
GLIBC_2.39 stdc_trailing_zeros_us F
GLIBC_2.41 sched_getattr F
GLIBC_2.41 sched_setattr F
GLIBC_2.42 pthread_gettid_np F

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@@ -2514,3 +2514,4 @@ GLIBC_2.39 stdc_trailing_zeros_us F
GLIBC_2.40 __riscv_hwprobe F
GLIBC_2.41 sched_getattr F
GLIBC_2.41 sched_setattr F
GLIBC_2.42 pthread_gettid_np F

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@@ -2714,3 +2714,4 @@ GLIBC_2.39 stdc_trailing_zeros_us F
GLIBC_2.40 __riscv_hwprobe F
GLIBC_2.41 sched_getattr F
GLIBC_2.41 sched_setattr F
GLIBC_2.42 pthread_gettid_np F

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@@ -3138,6 +3138,7 @@ GLIBC_2.4 wprintf F
GLIBC_2.4 wscanf F
GLIBC_2.41 sched_getattr F
GLIBC_2.41 sched_setattr F
GLIBC_2.42 pthread_gettid_np F
GLIBC_2.5 __readlinkat_chk F
GLIBC_2.5 inet6_opt_append F
GLIBC_2.5 inet6_opt_find F

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@@ -2931,6 +2931,7 @@ GLIBC_2.4 wprintf F
GLIBC_2.4 wscanf F
GLIBC_2.41 sched_getattr F
GLIBC_2.41 sched_setattr F
GLIBC_2.42 pthread_gettid_np F
GLIBC_2.5 __readlinkat_chk F
GLIBC_2.5 inet6_opt_append F
GLIBC_2.5 inet6_opt_find F

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@@ -2830,6 +2830,7 @@ GLIBC_2.4 unlinkat F
GLIBC_2.4 unshare F
GLIBC_2.41 sched_getattr F
GLIBC_2.41 sched_setattr F
GLIBC_2.42 pthread_gettid_np F
GLIBC_2.5 __readlinkat_chk F
GLIBC_2.5 inet6_opt_append F
GLIBC_2.5 inet6_opt_find F

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@@ -2827,6 +2827,7 @@ GLIBC_2.4 unlinkat F
GLIBC_2.4 unshare F
GLIBC_2.41 sched_getattr F
GLIBC_2.41 sched_setattr F
GLIBC_2.42 pthread_gettid_np F
GLIBC_2.5 __readlinkat_chk F
GLIBC_2.5 inet6_opt_append F
GLIBC_2.5 inet6_opt_find F

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@@ -3159,6 +3159,7 @@ GLIBC_2.4 wprintf F
GLIBC_2.4 wscanf F
GLIBC_2.41 sched_getattr F
GLIBC_2.41 sched_setattr F
GLIBC_2.42 pthread_gettid_np F
GLIBC_2.5 __readlinkat_chk F
GLIBC_2.5 inet6_opt_append F
GLIBC_2.5 inet6_opt_find F

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@@ -2795,6 +2795,7 @@ GLIBC_2.4 unlinkat F
GLIBC_2.4 unshare F
GLIBC_2.41 sched_getattr F
GLIBC_2.41 sched_setattr F
GLIBC_2.42 pthread_gettid_np F
GLIBC_2.5 __readlinkat_chk F
GLIBC_2.5 inet6_opt_append F
GLIBC_2.5 inet6_opt_find F

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@@ -2746,6 +2746,7 @@ GLIBC_2.4 unlinkat F
GLIBC_2.4 unshare F
GLIBC_2.41 sched_getattr F
GLIBC_2.41 sched_setattr F
GLIBC_2.42 pthread_gettid_np F
GLIBC_2.5 __readlinkat_chk F
GLIBC_2.5 inet6_opt_append F
GLIBC_2.5 inet6_opt_find F

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@@ -2765,3 +2765,4 @@ GLIBC_2.39 stdc_trailing_zeros_ull F
GLIBC_2.39 stdc_trailing_zeros_us F
GLIBC_2.41 sched_getattr F
GLIBC_2.41 sched_setattr F
GLIBC_2.42 pthread_gettid_np F