From 91d7242a440cad05bad95b793b7ce2110d50ea1e Mon Sep 17 00:00:00 2001
From: Simon Sundberg <simon.sundberg@kau.se>
Date: Thu, 3 Nov 2022 18:27:04 +0100
Subject: [PATCH] pping: Abort program if map cleanup fails

Previously the program would only print out an error message if the
cleanup of a map failed, and then keep running. Each time the
periodical cleanup failed the error message would be repeated, but no
further action taken. Change this behavior so that the program instead
terminates the cleanup thread and aborts the rest of the program.

Signed-off-by: Simon Sundberg <simon.sundberg@kau.se>
---
 pping/pping.c | 32 +++++++++++++++++++++++---------
 1 file changed, 23 insertions(+), 9 deletions(-)

diff --git a/pping/pping.c b/pping/pping.c
index c40fb7eb..62dda4fa 100644
--- a/pping/pping.c
+++ b/pping/pping.c
@@ -62,6 +62,7 @@ struct map_cleanup_args {
 	struct bpf_link *tsclean_link;
 	struct bpf_link *flowclean_link;
 	__u64 cleanup_interval;
+	int err;
 	bool valid_thread;
 };
 
@@ -562,28 +563,37 @@ static void *periodic_map_cleanup(void *args)
 	interval.tv_sec = argp->cleanup_interval / NS_PER_SECOND;
 	interval.tv_nsec = argp->cleanup_interval % NS_PER_SECOND;
 	char buf[256];
-	int err;
+	int err1, err2;
 
+	argp->err = 0;
 	while (keep_running) {
-		err = iter_map_execute(argp->tsclean_link);
-		if (err) {
+		err1 = iter_map_execute(argp->tsclean_link);
+		if (err1) {
 			// Running in separate thread so can't use get_libbpf_strerror
-			libbpf_strerror(err, buf, sizeof(buf));
+			libbpf_strerror(err1, buf, sizeof(buf));
 			fprintf(stderr,
 				"Error while cleaning timestamp map: %s\n",
 				buf);
 		}
 
-		err = iter_map_execute(argp->flowclean_link);
-		if (err) {
-			libbpf_strerror(err, buf, sizeof(buf));
+		err2 = iter_map_execute(argp->flowclean_link);
+		if (err2) {
+			libbpf_strerror(err2, buf, sizeof(buf));
 			fprintf(stderr, "Error while cleaning flow map: %s\n",
 				buf);
 		}
 
+		if (err1 || err2) {
+			fprintf(stderr,
+				"Failed cleaning maps - aborting program\n");
+			argp->err = err1 ? err1 : err2;
+			abort_program(SIGUSR1);
+			break;
+		}
+
 		nanosleep(&interval, NULL);
 	}
-	pthread_exit(NULL);
+	pthread_exit(&argp->err);
 }
 
 static __u64 convert_monotonic_to_realtime(__u64 monotonic_time)
@@ -979,6 +989,7 @@ static int setup_periodical_map_cleaning(struct bpf_object *obj,
 					 struct pping_config *config)
 {
 	int err;
+	config->clean_args.err = 0;
 
 	if (config->clean_args.valid_thread) {
 		fprintf(stderr,
@@ -1031,6 +1042,7 @@ static int setup_periodical_map_cleaning(struct bpf_object *obj,
 int main(int argc, char *argv[])
 {
 	int err = 0, detach_err;
+	void *thread_err;
 	struct bpf_object *obj = NULL;
 	struct perf_buffer *pb = NULL;
 
@@ -1153,7 +1165,9 @@ int main(int argc, char *argv[])
 
 	if (config.clean_args.valid_thread) {
 		pthread_cancel(config.clean_args.tid);
-		pthread_join(config.clean_args.tid, NULL);
+		pthread_join(config.clean_args.tid, &thread_err);
+		if (thread_err != PTHREAD_CANCELED)
+			err = err ? err : config.clean_args.err;
 
 		bpf_link__destroy(config.clean_args.tsclean_link);
 		bpf_link__destroy(config.clean_args.flowclean_link);