bpo-35823: subprocess: Fix handling of pthread_sigmask() errors (GH-22944)

Using POSIX_CALL() is incorrect since pthread_sigmask() returns
the error number instead of setting errno.

Also handle failure of the first call to pthread_sigmask()
in the parent process, and explain why we don't handle failure
of the second call in a comment.
This commit is contained in:
Alexey Izbyshev 2020-10-24 20:47:38 +03:00 committed by GitHub
parent e01e442125
commit 473db47747
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1 changed files with 15 additions and 4 deletions

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@ -581,7 +581,9 @@ child_exec(char *const exec_array[],
#ifdef VFORK_USABLE
if (child_sigmask) {
reset_signal_handlers(child_sigmask);
POSIX_CALL(pthread_sigmask(SIG_SETMASK, child_sigmask, NULL));
if ((errno = pthread_sigmask(SIG_SETMASK, child_sigmask, NULL))) {
goto error;
}
}
#endif
@ -1007,7 +1009,11 @@ subprocess_fork_exec(PyObject* self, PyObject *args)
*/
sigset_t all_sigs;
sigfillset(&all_sigs);
pthread_sigmask(SIG_BLOCK, &all_sigs, &old_sigs);
if ((saved_errno = pthread_sigmask(SIG_BLOCK, &all_sigs, &old_sigs))) {
errno = saved_errno;
PyErr_SetFromErrno(PyExc_OSError);
goto cleanup;
}
old_sigmask = &old_sigs;
}
#endif
@ -1034,8 +1040,13 @@ subprocess_fork_exec(PyObject* self, PyObject *args)
* Note that in environments where vfork() is implemented as fork(),
* such as QEMU user-mode emulation, the parent won't be blocked,
* but it won't share the address space with the child,
* so it's still safe to unblock the signals. */
pthread_sigmask(SIG_SETMASK, old_sigmask, NULL);
* so it's still safe to unblock the signals.
*
* We don't handle errors here because this call can't fail
* if valid arguments are given, and because there is no good
* way for the caller to deal with a failure to restore
* the thread signal mask. */
(void) pthread_sigmask(SIG_SETMASK, old_sigmask, NULL);
}
#endif