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author | Adhemerval Zanella <adhemerval.zanella@linaro.org> | 2020-12-07 16:21:55 -0300 |
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committer | Adhemerval Zanella <adhemerval.zanella@linaro.org> | 2021-06-09 15:16:45 -0300 |
commit | f779b1efb35fe141e47952af3ac7f0540acca401 (patch) | |
tree | c85d1e5a2b7f93048159938802f187d98a1b8d09 /nptl/pthread_kill.c | |
parent | 8c1c0aae2079039a629b15098d78f3d11aabefb4 (diff) | |
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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/pthread_kill.c')
-rw-r--r-- | nptl/pthread_kill.c | 42 |
1 files changed, 29 insertions, 13 deletions
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 |