From 675d4b3b3df1cb16ffe2ed94b1600262b6f76f63 Mon Sep 17 00:00:00 2001
From: Suvendhu Hansa <suvendhu.hansa@iopsys.eu>
Date: Wed, 4 Feb 2026 19:48:16 +0530
Subject: [PATCH] Collect cpe port from netstat on failure

---
 bbf_plugin/datamodel.c | 44 ++++++++++++++++++++++++++++++++++++++++--
 src/cwmp.c             | 13 +++++++++++++
 2 files changed, 55 insertions(+), 2 deletions(-)

diff --git a/bbf_plugin/datamodel.c b/bbf_plugin/datamodel.c
index fb0d5e6..bcbe5cb 100644
--- a/bbf_plugin/datamodel.c
+++ b/bbf_plugin/datamodel.c
@@ -515,6 +515,25 @@ static int set_management_server_periodic_inform_time(char *refparam, struct dmc
 	return 0;
 }
 
+static int read_daemon_pid(void)
+{
+	// cppcheck-suppress cert-MSC24-C
+	FILE *fp = fopen("/var/run/icwmpd.pid", "r");
+	if (fp == NULL) {
+		// If file doesn't exist, daemon isn't running or didn't create it yet
+		return -1;
+	}
+
+	int pid = 0;
+	// Read the integer from the file
+	if (fscanf(fp, "%d", &pid) != 1) {
+		pid = 0; // Could not parse an integer
+	}
+
+	fclose(fp);
+	return pid;
+}
+
 static void get_management_ip_port(char **listen_addr)
 {
 	char *ip = NULL, *port = NULL, *interface = NULL, *ip_version = NULL;
@@ -525,8 +544,29 @@ static void get_management_ip_port(char **listen_addr)
 	dmuci_get_option_value_string_varstate("icwmp", "cpe", "port", &port);
 	dmuci_get_option_value_string_varstate("icwmp", "acs", "ip_version", &ip_version);
 
-	if (DM_STRLEN(port) == 0)
-		port = dmstrdup("7547");
+	if (DM_STRLEN(port) == 0) {
+		int pid = read_daemon_pid();
+		if (pid > 0) {
+			BBFDM_ERR("CPE port not found in /var/state, fallback to netstat for port information");
+			char cmd[128] = {0}, line[16] = {0};
+
+			snprintf(cmd, sizeof(cmd), "netstat -nltp 2>/dev/null | grep \'%d/icwmpd\' | awk \'{print $4}\' | sed \'s/.*://\'", pid);
+			// Flawfinder: ignore
+			FILE *pp = popen(cmd, "r");
+			if (pp) {
+				fgets(line, sizeof(line), pp);
+				pclose(pp);
+			}
+
+			int len = DM_STRLEN(line);
+			if (len == 0)
+				BBFDM_INFO("CWMP port not found in netstat, icwmpd may be stopped");
+			else if (line[len - 1] == '\n')
+				line[len - 1] = '\0'; // omit \n from end
+
+			port = dmstrdup(line);
+		}
+	}
 
 	if (DM_STRLEN(l3_device) == 0 && DM_STRLEN(interface) != 0)
 		l3_device = get_l3_device(interface);
diff --git a/src/cwmp.c b/src/cwmp.c
index 0404c54..d9915de 100644
--- a/src/cwmp.c
+++ b/src/cwmp.c
@@ -182,6 +182,11 @@ static int cwmp_init(void)
 	/* Only One instance should run*/
 	// cppcheck-suppress cert-MSC24-C
 	cwmp_ctx.pid_file = fopen("/var/run/icwmpd.pid", "w+");
+	if (!cwmp_ctx.pid_file) {
+		CWMP_LOG(ERROR, "%s", "Could not open pid file");
+		exit(EXIT_FAILURE);
+	}
+
 	fcntl(fileno(cwmp_ctx.pid_file), F_SETFD, fcntl(fileno(cwmp_ctx.pid_file), F_GETFD) | FD_CLOEXEC);
 	int rc = flock(fileno(cwmp_ctx.pid_file), LOCK_EX | LOCK_NB);
 	if (rc) {
@@ -194,6 +199,14 @@ static int cwmp_init(void)
 			exit(EXIT_SUCCESS);
 	}
 
+	/* Write the pid */
+	// cppcheck-suppress cert-MSC24-C
+	rewind(cwmp_ctx.pid_file);
+	ftruncate(fileno(cwmp_ctx.pid_file), 0);
+	fprintf(cwmp_ctx.pid_file, "%d\n", getpid());
+	fflush(cwmp_ctx.pid_file);
+	fsync(fileno(cwmp_ctx.pid_file));
+
 	if (CWMP_OK != create_cwmp_temporary_files()) {
 		return CWMP_GEN_ERR;
 	}