feat(syscall): 实现syscall restart (#1075)

能够在系统调用返回ERESTARTSYS时,信号处理结束后,自动重启系统调用.

TODO: 实现wait等需要restart_block的系统调用的重启

Signed-off-by: longjin <longjin@DragonOS.org>

user/apps/test-sigprocmask/main.c

@@ -62,9 +62,11 @@ int main() {
         perror("signal");
         exit(EXIT_FAILURE);
     }
-
+    printf("Signal handler for SIGINT is registered.\n");
     signal_received = 0;
     kill(getpid(), SIGINT);
+    sleep(5);
+
     TEST_ASSERT(signal_received, 1, "SIGINT was received", "SIGINT was not received");
     signal_received = 0;