Revert "kernel/thread: restore signal mask just before returning to userland"

This reverts commit 837f4f48db.

Reason for revert: breaks DNS resolution

Change-Id: If6f2a0f60dbfb24121616a9f3879ce226ea4a09a
Reviewed-on: https://review.haiku-os.org/c/haiku/+/3519
Reviewed-by: Jérôme Duval <[email protected]>

headers/private/kernel/thread_types.h

@@ -455,10 +455,6 @@ struct Thread : TeamThreadIteratorEntry<thread_id>, KernelReferenceable {
 		// non-0 after a return from _user_sigsuspend(), containing the inverted
 		// original signal mask, reset in handle_signals(); only accessed by
 		// this thread
-	sigset_t		old_sig_block_mask;
-		// the old sig_block_mask to be restored when returning to userland
-		// when THREAD_FLAGS_OLD_SIGMASK is set
-
 	ucontext_t*		user_signal_context;	// only accessed by this thread
 	addr_t			signal_stack_base;		// only accessed by this thread
 	size_t			signal_stack_size;		// only accessed by this thread
@@ -848,7 +844,5 @@ using BKernel::ProcessGroupList;
 #define	THREAD_FLAGS_COMPAT_MODE			0x2000
 	// the thread runs a compatibility mode (for instance IA32 on x86_64).
 #endif
-#define	THREAD_FLAGS_OLD_SIGMASK			0x4000
-	// the thread has an old sigmask to be restored
 
 #endif	/* _KERNEL_THREAD_TYPES_H */

src/system/kernel/thread.cpp

@@ -1938,16 +1938,6 @@ dump_thread_list(int argc, char **argv)
 }
 
 
-static void
-update_thread_sigmask_on_exit(Thread* thread)
-{
-	if ((thread->flags & THREAD_FLAGS_OLD_SIGMASK) != 0) {
-		thread->flags &= ~THREAD_FLAGS_OLD_SIGMASK;
-		sigprocmask(SIG_SETMASK, &thread->old_sig_block_mask, NULL);
-	}
-}
-
-
 //	#pragma mark - private kernel API
 
 
@@ -2328,8 +2318,6 @@ thread_at_kernel_exit(void)
 
 	disable_interrupts();
 
-	update_thread_sigmask_on_exit(thread);
-
 	// track kernel time
 	bigtime_t now = system_time();
 	SpinLocker threadTimeLocker(thread->time_lock);
@@ -2351,8 +2339,6 @@ thread_at_kernel_exit_no_signals(void)
 	TRACE(("thread_at_kernel_exit_no_signals: exit thread %" B_PRId32 "\n",
 		thread->id));
 
-	update_thread_sigmask_on_exit(thread);
-
 	// track kernel time
 	bigtime_t now = system_time();
 	SpinLocker threadTimeLocker(thread->time_lock);

src/system/kernel/wait_for_objects.cpp

@@ -475,21 +475,15 @@ common_select(int numFDs, fd_set *readSet, fd_set *writeSet, fd_set *errorSet,
 
 	// set new signal mask
 	sigset_t oldSigMask;
-	if (sigMask != NULL) {
+	if (sigMask != NULL)
 		sigprocmask(SIG_SETMASK, sigMask, &oldSigMask);
-		if (!kernel) {
-			Thread *thread = thread_get_current_thread();
-			thread->old_sig_block_mask = oldSigMask;
-			thread->flags |= THREAD_FLAGS_OLD_SIGMASK;
-		}
-	}
 
 	// wait for something to happen
 	status = acquire_sem_etc(sync->sem, 1,
 		B_CAN_INTERRUPT | (timeout >= 0 ? B_ABSOLUTE_TIMEOUT : 0), timeout);
 
 	// restore the old signal mask
-	if (sigMask != NULL && kernel)
+	if (sigMask != NULL)
 		sigprocmask(SIG_SETMASK, &oldSigMask, NULL);
 
 	PRINT(("common_select(): acquire_sem_etc() returned: %lx\n", status));
@@ -933,6 +927,8 @@ _user_select(int numFDs, fd_set *userReadSet, fd_set *userWriteSet,
 	sigset_t sigMask;
 	int result;
 
+	syscall_restart_handle_timeout_pre(timeout);
+
 	if (numFDs < 0 || !check_max_fds(numFDs))
 		return B_BAD_VALUE;
 
@@ -998,7 +994,8 @@ _user_select(int numFDs, fd_set *userReadSet, fd_set *userWriteSet,
 			|| (errorSet != NULL
 				&& user_memcpy(userErrorSet, errorSet, bytes) < B_OK))) {
 		result = B_BAD_ADDRESS;
-	}
+	} else
+		syscall_restart_handle_timeout_post(result, timeout);
 
 err:
 	free(readSet);
@@ -1016,12 +1013,16 @@ _user_poll(struct pollfd *userfds, int numFDs, bigtime_t timeout)
 	size_t bytes;
 	int result;
 
+	syscall_restart_handle_timeout_pre(timeout);
+
 	if (numFDs < 0)
 		return B_BAD_VALUE;
 
 	if (numFDs == 0) {
 		// special case: no FDs
-		return common_poll(NULL, 0, timeout, false);
+		result = common_poll(NULL, 0, timeout, false);
+		return result < 0
+			? syscall_restart_handle_timeout_post(result, timeout) : result;
 	}
 
 	if (!check_max_fds(numFDs))
@@ -1046,7 +1047,9 @@ _user_poll(struct pollfd *userfds, int numFDs, bigtime_t timeout)
 	if (numFDs > 0 && user_memcpy(userfds, fds, bytes) != 0) {
 		if (result >= 0)
 			result = B_BAD_ADDRESS;
-	}
+	} else
+		syscall_restart_handle_timeout_post(result, timeout);
+
 err:
 	free(fds);