From c17f5df6cd520170dccbfdbebd8703626effb2bf Mon Sep 17 00:00:00 2001
From: Nick Peng <pymumu@gmail.com>
Date: Wed, 6 Dec 2023 23:03:32 +0800
Subject: [PATCH] smartdns: optimize smartdns.c readability

---
 src/smartdns.c | 46 ++++++++++++++++++++++++++++++++--------------
 src/util.c     | 16 ++++++++++++----
 src/util.h     |  9 ++++++++-
 3 files changed, 52 insertions(+), 19 deletions(-)

diff --git a/src/smartdns.c b/src/smartdns.c
index 5431f109df..561c4682fd 100644
--- a/src/smartdns.c
+++ b/src/smartdns.c
@@ -828,12 +828,12 @@ static smartdns_run_monitor_ret _smartdns_run_monitor(int restart_when_crash, in
 	}
 
 	if (is_run_as_daemon) {
-		int daemon_ret = daemon_run();
-		if (daemon_ret != -2) {
-			if (daemon_ret == 0) {
-				return SMARTDNS_RUN_MONITOR_EXIT;
-			}
-
+		switch (daemon_run(NULL)) {
+		case DAEMON_RET_CHILD_OK:
+			break;
+		case DAEMON_RET_PARENT_OK:
+			return SMARTDNS_RUN_MONITOR_EXIT;
+		default:
 			return SMARTDNS_RUN_MONITOR_ERROR;
 		}
 	}
@@ -898,6 +898,16 @@ static smartdns_run_monitor_ret _smartdns_run_monitor(int restart_when_crash, in
 	return SMARTDNS_RUN_MONITOR_ERROR;
 }
 
+static void _smartdns_print_error_tip(void)
+{
+	char buff[4096];
+	char *log_path = realpath(_smartdns_log_path(), buff);
+
+	if (log_path != NULL && access(log_path, F_OK) == 0) {
+		fprintf(stderr, "run daemon failed, please check log at %s\n", log_path);
+	}
+}
+
 #ifdef TEST
 
 static smartdns_post_func _smartdns_post = NULL;
@@ -1030,16 +1040,21 @@ int main(int argc, char *argv[])
 	}
 
 	if (is_run_as_daemon) {
-		int daemon_ret = daemon_run();
-		if (daemon_ret != -2) {
-			char buff[4096];
-			char *log_path = realpath(_smartdns_log_path(), buff);
-
-			if (log_path != NULL && access(log_path, F_OK) == 0 && daemon_ret != -3 && daemon_ret != 0) {
-				fprintf(stderr, "run daemon failed, please check log at %s\n", log_path);
+		int child_status = -1;
+		switch (daemon_run(&child_status)) {
+		case DAEMON_RET_CHILD_OK:
+			break;
+		case DAEMON_RET_PARENT_OK: {
+			if (child_status != 0 && child_status != -3) {
+				_smartdns_print_error_tip();
 			}
 
-			return daemon_ret;
+			return child_status;
+		} break;
+		case DAEMON_RET_ERR:
+		default:
+			fprintf(stderr, "run daemon failed.\n");
+			goto errout;
 		}
 	}
 
@@ -1097,6 +1112,9 @@ int main(int argc, char *argv[])
 errout:
 	if (is_run_as_daemon) {
 		daemon_kickoff(ret, dns_conf_log_console | verbose_screen);
+	} else {
+		_smartdns_print_error_tip();
+		printf("ret = %d\n", ret);
 	}
 	smartdns_test_notify(2);
 	_smartdns_exit();
diff --git a/src/util.c b/src/util.c
index 526c1af3a4..91b9348523 100644
--- a/src/util.c
+++ b/src/util.c
@@ -1703,7 +1703,7 @@ int daemon_keepalive(void)
 	return 0;
 }
 
-int daemon_run(void)
+daemon_ret daemon_run(int *wstatus)
 {
 	pid_t pid = 0;
 	int fds[2] = {0};
@@ -1753,11 +1753,16 @@ int daemon_run(void)
 				pid = msg.value;
 				continue;
 			} else if (msg.type == DAEMON_MSG_KICKOFF) {
-				return msg.value;
+				if (wstatus != NULL) {
+					*wstatus = msg.value;
+				}
+				return DAEMON_RET_PARENT_OK;
 			} else {
 				goto errout;
 			}
 		} while (true);
+
+		return DAEMON_RET_ERR;
 	}
 
 	setsid();
@@ -1782,10 +1787,13 @@ int daemon_run(void)
 	close(fds[0]);
 
 	daemon_fd = fds[1];
-	return -2;
+	return DAEMON_RET_CHILD_OK;
 errout:
 	kill(pid, SIGKILL);
-	return -1;
+	if (wstatus != NULL) {
+		*wstatus = -1;
+	}
+	return DAEMON_RET_ERR;
 }
 
 #ifdef DEBUG
diff --git a/src/util.h b/src/util.h
index 7a417de14f..8783815d98 100644
--- a/src/util.h
+++ b/src/util.h
@@ -147,7 +147,14 @@ void print_stack(void);
 
 void close_all_fd(int keepfd);
 
-int daemon_run(void);
+typedef enum daemon_ret {
+	DAEMON_RET_OK = 0,
+	DAEMON_RET_ERR = -1,
+	DAEMON_RET_CHILD_OK = -2,
+	DAEMON_RET_PARENT_OK = -3,
+} daemon_ret;
+
+daemon_ret daemon_run(int *wstatus);
 
 int daemon_kickoff(int status, int no_close);