passt, util: Move opening of PID file to its own function

We won't call it from main() any longer: move it.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: Richard W.M. Jones <rjones@redhat.com>

passt.c

@@ -199,7 +199,7 @@ void exit_handler(int signal)
  */
 int main(int argc, char **argv)
 {
-	int nfds, i, devnull_fd = -1, pidfile_fd = -1;
+	int nfds, i, devnull_fd = -1, pidfile_fd;
 	struct epoll_event events[EPOLL_EVENTS];
 	char *log_name, argv0[PATH_MAX], *name;
 	struct ctx c = { 0 };
@@ -299,14 +299,7 @@ int main(int argc, char **argv)
 		}
 	}
 
-	if (*c.pid_file) {
+	pidfile_fd = pidfile_open(c.pid_file);
-		if ((pidfile_fd = open(c.pid_file,
-				       O_CREAT | O_TRUNC | O_WRONLY | O_CLOEXEC,
-				       S_IRUSR | S_IWUSR)) < 0) {
-			perror("PID file open");
-			exit(EXIT_FAILURE);
-		}
-	}
 
 	if (isolate_prefork(&c))
 		die("Failed to sandbox process, exiting");

util.c

@@ -402,6 +402,28 @@ void pidfile_write(int fd, pid_t pid)
 	close(fd);
 }
 
+/**
+ * pidfile_open() - Open PID file if needed
+ * @path:	Path for PID file, empty string if no PID file is requested
+ *
+ * Return: descriptor for PID file, -1 if path is NULL, won't return on failure
+ */
+int pidfile_open(const char *path)
+{
+	int fd;
+
+	if (!*path)
+		return -1;
+
+	if ((fd = open(path, O_CREAT | O_TRUNC | O_WRONLY | O_CLOEXEC,
+			     S_IRUSR | S_IWUSR)) < 0) {
+		perror("PID file open");
+		exit(EXIT_FAILURE);
+	}
+
+	return fd;
+}
+
 /**
  * __daemon() - daemon()-like function writing PID file before parent exits
  * @pidfile_fd:	Open PID file descriptor

util.h

@@ -156,6 +156,7 @@ char *line_read(char *buf, size_t len, int fd);
 void ns_enter(const struct ctx *c);
 bool ns_is_init(void);
 int open_in_ns(const struct ctx *c, const char *path, int flags);
+int pidfile_open(const char *path);
 void pidfile_write(int fd, pid_t pid);
 int __daemon(int pidfile_fd, int devnull_fd);
 int fls(unsigned long x);