unix/Daemon: move code to ReadPidFile()

src/unix/Daemon.cxx

@@ -65,25 +65,15 @@ static int detach_fd = -1;
 void
 daemonize_kill(void)
 {
-	FILE *fp;
-	int pid;
-
 	if (pidfile.IsNull())
 		FatalError("no pid_file specified in the config file");
 
-	fp = FOpen(pidfile, PATH_LITERAL("r"));
-	if (fp == nullptr) {
-		const std::string utf8 = pidfile.ToUTF8();
-		FormatFatalSystemError("Unable to open pid file \"%s\"",
-				       utf8.c_str());
-	}
-
-	if (fscanf(fp, "%i", &pid) != 1) {
+	const pid_t pid = ReadPidFile(pidfile);
+	if (pid < 0) {
 		const std::string utf8 = pidfile.ToUTF8();
 		FormatFatalError("unable to read the pid from file \"%s\"",
 				 utf8.c_str());
 	}
-	fclose(fp);
 
 	if (kill(pid, SIGTERM) < 0)
 		FormatFatalSystemError("unable to kill process %i",

src/unix/PidFile.hxx

@@ -82,4 +82,20 @@ public:
 	}
 };
 
+gcc_pure
+static inline pid_t
+ReadPidFile(Path path)
+{
+	FILE *fp = FOpen(path, PATH_LITERAL("r"));
+	if (fp == nullptr)
+		return -1;
+
+	int pid;
+	if (fscanf(fp, "%i", &pid) != 1)
+		pid = -1;
+
+	fclose(fp);
+	return pid;
+}
+
 #endif