process-util: add pidref_is_unwaited() and make pid_is_unwaited() return errors

src/basic/process-util.c

@@ -1045,11 +1045,11 @@ int pidref_is_my_child(const PidRef *pid) {
         return result;
 }
 
-bool pid_is_unwaited(pid_t pid) {
+int pid_is_unwaited(pid_t pid) {
         /* Checks whether a PID is still valid at all, including a zombie */
 
         if (pid < 0)
-                return false;
+                return -ESRCH;
 
         if (pid <= 1) /* If we or PID 1 would be dead and have been waited for, this code would not be running */
                 return true;
@@ -1063,6 +1063,24 @@ bool pid_is_unwaited(pid_t pid) {
         return errno != ESRCH;
 }
 
+int pidref_is_unwaited(const PidRef *pid) {
+        int r;
+
+        if (!pidref_is_set(pid))
+                return -ESRCH;
+
+        if (pid->pid == 1 || pidref_is_self(pid))
+                return true;
+
+        r = pidref_kill(pid, 0);
+        if (r == -ESRCH)
+                return false;
+        if (r < 0)
+                return r;
+
+        return true;
+}
+
 int pid_is_alive(pid_t pid) {
         int r;
 

src/basic/process-util.h

@@ -88,7 +88,8 @@ int getenv_for_pid(pid_t pid, const char *field, char **_value);
 
 int pid_is_alive(pid_t pid);
 int pidref_is_alive(const PidRef *pidref);
-bool pid_is_unwaited(pid_t pid);
+int pid_is_unwaited(pid_t pid);
+int pidref_is_unwaited(const PidRef *pidref);
 int pid_is_my_child(pid_t pid);
 int pidref_is_my_child(const PidRef *pidref);
 int pid_from_same_root_fs(pid_t pid);