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authorAdhemerval Zanella <adhemerval.zanella@linaro.org>2020-12-07 16:21:55 -0300
committerAdhemerval Zanella <adhemerval.zanella@linaro.org>2021-06-09 15:16:45 -0300
commitf779b1efb35fe141e47952af3ac7f0540acca401 (patch)
treec85d1e5a2b7f93048159938802f187d98a1b8d09 /nptl
parent8c1c0aae2079039a629b15098d78f3d11aabefb4 (diff)
downloadglibc-f779b1efb35fe141e47952af3ac7f0540acca401.tar.gz
nptl: Implement raise in terms of pthread_kill
Now that pthread_kill is provided by libc.so it is possible to implement the generic POSIX implementation as 'pthread_kill(pthread_self(), sig)'. For Linux implementation, pthread_kill read the targeting TID from the TCB. For raise, this it not possible because it would make raise fail when issue after vfork (where creates the resulting process has a different TID from the parent, but its TCB is not updated as for pthread_create). To make raise use pthread_kill, it is make usable from vfork by getting the target thread id through gettid syscall. Checked on x86_64-linux-gnu and aarch64-linux-gnu.
Diffstat (limited to 'nptl')
-rw-r--r--nptl/Makefile1
-rw-r--r--nptl/pthreadP.h4
-rw-r--r--nptl/pthread_kill.c42
-rw-r--r--nptl/pthread_self.c4
4 files changed, 36 insertions, 15 deletions
diff --git a/nptl/Makefile b/nptl/Makefile
index f7d7a2c7e2..3e6cf0c21b 100644
--- a/nptl/Makefile
+++ b/nptl/Makefile
@@ -251,6 +251,7 @@ CFLAGS-pthread_clockjoin.c += -fexceptions -fasynchronous-unwind-tables
CFLAGS-pthread_once.c += $(uses-callbacks) -fexceptions \
-fasynchronous-unwind-tables
CFLAGS-pthread_cond_wait.c += -fexceptions -fasynchronous-unwind-tables
+CFLAGS-pthread_kill.c = -fexceptions -fasynchronous-unwind-tables
CFLAGS-sem_wait.c += -fexceptions -fasynchronous-unwind-tables
CFLAGS-sem_timedwait.c += -fexceptions -fasynchronous-unwind-tables
CFLAGS-sem_clockwait.c = -fexceptions -fasynchronous-unwind-tables
diff --git a/nptl/pthreadP.h b/nptl/pthreadP.h
index 3e7a4f52ab..618922f47a 100644
--- a/nptl/pthreadP.h
+++ b/nptl/pthreadP.h
@@ -508,11 +508,13 @@ extern int __pthread_once (pthread_once_t *once_control,
libc_hidden_proto (__pthread_once)
extern int __pthread_atfork (void (*prepare) (void), void (*parent) (void),
void (*child) (void));
-extern pthread_t __pthread_self (void);
+libc_hidden_proto (__pthread_self)
extern int __pthread_equal (pthread_t thread1, pthread_t thread2);
extern int __pthread_detach (pthread_t th);
libc_hidden_proto (__pthread_detach)
extern int __pthread_kill (pthread_t threadid, int signo);
+libc_hidden_proto (__pthread_kill)
+extern int __pthread_cancel (pthread_t th);
extern void __pthread_exit (void *value) __attribute__ ((__noreturn__));
libc_hidden_proto (__pthread_exit)
extern int __pthread_join (pthread_t threadid, void **thread_return);
diff --git a/nptl/pthread_kill.c b/nptl/pthread_kill.c
index ad7e011779..8982011ba8 100644
--- a/nptl/pthread_kill.c
+++ b/nptl/pthread_kill.c
@@ -28,24 +28,40 @@ __pthread_kill (pthread_t threadid, int signo)
if (__is_internal_signal (signo))
return EINVAL;
- /* Force load of pd->tid into local variable or register. Otherwise
- if a thread exits between ESRCH test and tgkill, we might return
- EINVAL, because pd->tid would be cleared by the kernel. */
+ pid_t tid;
struct pthread *pd = (struct pthread *) threadid;
- pid_t tid = atomic_forced_read (pd->tid);
- if (__glibc_unlikely (tid <= 0))
- /* Not a valid thread handle. */
- return ESRCH;
- /* We have a special syscall to do the work. */
- pid_t pid = __getpid ();
+ if (pd == THREAD_SELF)
+ /* It is a special case to handle raise() implementation after a vfork
+ call (which does not update the PD tid field). */
+ tid = INLINE_SYSCALL_CALL (gettid);
+ else
+ /* Force load of pd->tid into local variable or register. Otherwise
+ if a thread exits between ESRCH test and tgkill, we might return
+ EINVAL, because pd->tid would be cleared by the kernel. */
+ tid = atomic_forced_read (pd->tid);
- int val = INTERNAL_SYSCALL_CALL (tgkill, pid, tid, signo);
- return (INTERNAL_SYSCALL_ERROR_P (val)
- ? INTERNAL_SYSCALL_ERRNO (val) : 0);
+ int val;
+ if (__glibc_likely (tid > 0))
+ {
+ pid_t pid = __getpid ();
+
+ val = INTERNAL_SYSCALL_CALL (tgkill, pid, tid, signo);
+ val = (INTERNAL_SYSCALL_ERROR_P (val)
+ ? INTERNAL_SYSCALL_ERRNO (val) : 0);
+ }
+ else
+ val = ESRCH;
+
+ return val;
}
+/* Some architectures (for instance arm) might pull raise through libgcc, so
+ avoid the symbol version if it ends up being used on ld.so. */
+#if !IS_IN(rtld)
+libc_hidden_def (__pthread_kill)
versioned_symbol (libc, __pthread_kill, pthread_kill, GLIBC_2_34);
-#if OTHER_SHLIB_COMPAT (libpthread, GLIBC_2_0, GLIBC_2_34)
+# if OTHER_SHLIB_COMPAT (libpthread, GLIBC_2_0, GLIBC_2_34)
compat_symbol (libc, __pthread_kill, pthread_kill, GLIBC_2_0);
+# endif
#endif
diff --git a/nptl/pthread_self.c b/nptl/pthread_self.c
index f877a2e6bd..196d93fb8e 100644
--- a/nptl/pthread_self.c
+++ b/nptl/pthread_self.c
@@ -20,7 +20,9 @@
#include <tls.h>
pthread_t
-pthread_self (void)
+__pthread_self (void)
{
return (pthread_t) THREAD_SELF;
}
+libc_hidden_def (__pthread_self)
+weak_alias (__pthread_self, pthread_self)