coredump: parse signal number at the same time as parsing other fields

src/basic/signal-util.c

@@ -301,3 +301,19 @@ const struct sigaction sigaction_default = {
         .sa_handler = SIG_DFL,
         .sa_flags = SA_RESTART,
 };
+
+int parse_signo(const char *s, int *ret) {
+        int sig, r;
+
+        r = safe_atoi(s, &sig);
+        if (r < 0)
+                return r;
+
+        if (!SIGNAL_VALID(sig))
+                return -EINVAL;
+
+        if (ret)
+                *ret = sig;
+
+        return 0;
+}

src/basic/signal-util.h

@@ -68,3 +68,5 @@ void propagate_signal(int sig, siginfo_t *siginfo);
 
 extern const struct sigaction sigaction_ignore;
 extern const struct sigaction sigaction_default;
+
+int parse_signo(const char *s, int *ret);