tools/rtla: Add fatal() and replace error handling pattern

The code contains some technical debt in error handling,
which complicates the consolidation of duplicated code.

Introduce an fatal() function to replace the common pattern of
err_msg() followed by exit(EXIT_FAILURE), reducing the length of an
already long function.

Further patches using fatal() follow.

Signed-off-by: Costa Shulyupin <costa.shul@redhat.com>
Reviewed-by: Tomas Glozar <tglozar@redhat.com>
Link: https://lore.kernel.org/r/20251011082738.173670-2-costa.shul@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>

7 files changed, 81 insertions, 129 deletions

diff --git a/tools/tracing/rtla/src/osnoise_hist.c b/tools/tracing/rtla/src/osnoise_hist.c
index df0657b78980..d30a9a03b764 100644
--- a/tools/tracing/rtla/src/osnoise_hist.c
+++ b/tools/tracing/rtla/src/osnoise_hist.c
@@ -575,10 +575,8 @@ static struct common_params
 			break;
 		case 'e':
 			tevent = trace_event_alloc(optarg);
-			if (!tevent) {
-				err_msg("Error alloc trace event");
-				exit(EXIT_FAILURE);
-			}
+			if (!tevent)
+				fatal("Error alloc trace event");
 
 			if (params->common.events)
 				tevent->next = params->common.events;
@@ -598,10 +596,8 @@ static struct common_params
 		case 'H':
 			params->common.hk_cpus = 1;
 			retval = parse_cpu_set(optarg, &params->common.hk_cpu_set);
-			if (retval) {
-				err_msg("Error parsing house keeping CPUs\n");
-				exit(EXIT_FAILURE);
-			}
+			if (retval)
+				fatal("Error parsing house keeping CPUs");
 			break;
 		case 'p':
 			params->period = get_llong_from_str(optarg);
@@ -654,10 +650,8 @@ static struct common_params
 		case '4': /* trigger */
 			if (params->common.events) {
 				retval = trace_event_add_trigger(params->common.events, optarg);
-				if (retval) {
-					err_msg("Error adding trigger %s\n", optarg);
-					exit(EXIT_FAILURE);
-				}
+				if (retval)
+					fatal("Error adding trigger %s", optarg);
 			} else {
 				osnoise_hist_usage("--trigger requires a previous -e\n");
 			}
@@ -665,10 +659,8 @@ static struct common_params
 		case '5': /* filter */
 			if (params->common.events) {
 				retval = trace_event_add_filter(params->common.events, optarg);
-				if (retval) {
-					err_msg("Error adding filter %s\n", optarg);
-					exit(EXIT_FAILURE);
-				}
+				if (retval)
+					fatal("Error adding filter %s", optarg);
 			} else {
 				osnoise_hist_usage("--filter requires a previous -e\n");
 			}
@@ -682,18 +674,14 @@ static struct common_params
 		case '8':
 			retval = actions_parse(&params->common.threshold_actions, optarg,
 					       "osnoise_trace.txt");
-			if (retval) {
-				err_msg("Invalid action %s\n", optarg);
-				exit(EXIT_FAILURE);
-			}
+			if (retval)
+				fatal("Invalid action %s", optarg);
 			break;
 		case '9':
 			retval = actions_parse(&params->common.end_actions, optarg,
 					       "osnoise_trace.txt");
-			if (retval) {
-				err_msg("Invalid action %s\n", optarg);
-				exit(EXIT_FAILURE);
-			}
+			if (retval)
+				fatal("Invalid action %s", optarg);
 			break;
 		default:
 			osnoise_hist_usage("Invalid option");
@@ -703,10 +691,8 @@ static struct common_params
 	if (trace_output)
 		actions_add_trace_output(&params->common.threshold_actions, trace_output);
 
-	if (geteuid()) {
-		err_msg("rtla needs root permission\n");
-		exit(EXIT_FAILURE);
-	}
+	if (geteuid())
+		fatal("rtla needs root permission");
 
 	if (params->common.hist.no_index && !params->common.hist.with_zeros)
 		osnoise_hist_usage("no-index set and with-zeros not set - it does not make sense");
diff --git a/tools/tracing/rtla/src/osnoise_top.c b/tools/tracing/rtla/src/osnoise_top.c
index 1b5181e66b17..487daac8908c 100644
--- a/tools/tracing/rtla/src/osnoise_top.c
+++ b/tools/tracing/rtla/src/osnoise_top.c
@@ -421,10 +421,8 @@ struct common_params *osnoise_top_parse_args(int argc, char **argv)
 			break;
 		case 'e':
 			tevent = trace_event_alloc(optarg);
-			if (!tevent) {
-				err_msg("Error alloc trace event");
-				exit(EXIT_FAILURE);
-			}
+			if (!tevent)
+				fatal("Error alloc trace event");
 
 			if (params->common.events)
 				tevent->next = params->common.events;
@@ -438,10 +436,8 @@ struct common_params *osnoise_top_parse_args(int argc, char **argv)
 		case 'H':
 			params->common.hk_cpus = 1;
 			retval = parse_cpu_set(optarg, &params->common.hk_cpu_set);
-			if (retval) {
-				err_msg("Error parsing house keeping CPUs\n");
-				exit(EXIT_FAILURE);
-			}
+			if (retval)
+				fatal("Error parsing house keeping CPUs");
 			break;
 		case 'p':
 			params->period = get_llong_from_str(optarg);
@@ -485,10 +481,8 @@ struct common_params *osnoise_top_parse_args(int argc, char **argv)
 		case '0': /* trigger */
 			if (params->common.events) {
 				retval = trace_event_add_trigger(params->common.events, optarg);
-				if (retval) {
-					err_msg("Error adding trigger %s\n", optarg);
-					exit(EXIT_FAILURE);
-				}
+				if (retval)
+					fatal("Error adding trigger %s", optarg);
 			} else {
 				osnoise_top_usage(params, "--trigger requires a previous -e\n");
 			}
@@ -496,10 +490,8 @@ struct common_params *osnoise_top_parse_args(int argc, char **argv)
 		case '1': /* filter */
 			if (params->common.events) {
 				retval = trace_event_add_filter(params->common.events, optarg);
-				if (retval) {
-					err_msg("Error adding filter %s\n", optarg);
-					exit(EXIT_FAILURE);
-				}
+				if (retval)
+					fatal("Error adding filter %s", optarg);
 			} else {
 				osnoise_top_usage(params, "--filter requires a previous -e\n");
 			}
@@ -513,18 +505,14 @@ struct common_params *osnoise_top_parse_args(int argc, char **argv)
 		case '4':
 			retval = actions_parse(&params->common.threshold_actions, optarg,
 					       "osnoise_trace.txt");
-			if (retval) {
-				err_msg("Invalid action %s\n", optarg);
-				exit(EXIT_FAILURE);
-			}
+			if (retval)
+				fatal("Invalid action %s", optarg);
 			break;
 		case '5':
 			retval = actions_parse(&params->common.end_actions, optarg,
 					       "osnoise_trace.txt");
-			if (retval) {
-				err_msg("Invalid action %s\n", optarg);
-				exit(EXIT_FAILURE);
-			}
+			if (retval)
+				fatal("Invalid action %s", optarg);
 			break;
 		default:
 			osnoise_top_usage(params, "Invalid option");
@@ -534,10 +522,8 @@ struct common_params *osnoise_top_parse_args(int argc, char **argv)
 	if (trace_output)
 		actions_add_trace_output(&params->common.threshold_actions, trace_output);
 
-	if (geteuid()) {
-		err_msg("osnoise needs root permission\n");
-		exit(EXIT_FAILURE);
-	}
+	if (geteuid())
+		fatal("osnoise needs root permission");
 
 	return &params->common;
 }
diff --git a/tools/tracing/rtla/src/timerlat_hist.c b/tools/tracing/rtla/src/timerlat_hist.c
index c432ef5f59e7..f98deb16b452 100644
--- a/tools/tracing/rtla/src/timerlat_hist.c
+++ b/tools/tracing/rtla/src/timerlat_hist.c
@@ -894,10 +894,8 @@ static struct common_params
 			break;
 		case 'e':
 			tevent = trace_event_alloc(optarg);
-			if (!tevent) {
-				err_msg("Error alloc trace event");
-				exit(EXIT_FAILURE);
-			}
+			if (!tevent)
+				fatal("Error alloc trace event");
 
 			if (params->common.events)
 				tevent->next = params->common.events;
@@ -917,10 +915,8 @@ static struct common_params
 		case 'H':
 			params->common.hk_cpus = 1;
 			retval = parse_cpu_set(optarg, &params->common.hk_cpu_set);
-			if (retval) {
-				err_msg("Error parsing house keeping CPUs\n");
-				exit(EXIT_FAILURE);
-			}
+			if (retval)
+				fatal("Error parsing house keeping CPUs");
 			break;
 		case 'i':
 			params->common.stop_us = get_llong_from_str(optarg);
@@ -986,10 +982,8 @@ static struct common_params
 		case '6': /* trigger */
 			if (params->common.events) {
 				retval = trace_event_add_trigger(params->common.events, optarg);
-				if (retval) {
-					err_msg("Error adding trigger %s\n", optarg);
-					exit(EXIT_FAILURE);
-				}
+				if (retval)
+					fatal("Error adding trigger %s", optarg);
 			} else {
 				timerlat_hist_usage("--trigger requires a previous -e\n");
 			}
@@ -997,20 +991,16 @@ static struct common_params
 		case '7': /* filter */
 			if (params->common.events) {
 				retval = trace_event_add_filter(params->common.events, optarg);
-				if (retval) {
-					err_msg("Error adding filter %s\n", optarg);
-					exit(EXIT_FAILURE);
-				}
+				if (retval)
+					fatal("Error adding filter %s", optarg);
 			} else {
 				timerlat_hist_usage("--filter requires a previous -e\n");
 			}
 			break;
 		case '8':
 			params->dma_latency = get_llong_from_str(optarg);
-			if (params->dma_latency < 0 || params->dma_latency > 10000) {
-				err_msg("--dma-latency needs to be >= 0 and < 10000");
-				exit(EXIT_FAILURE);
-			}
+			if (params->dma_latency < 0 || params->dma_latency > 10000)
+				fatal("--dma-latency needs to be >= 0 and < 10000");
 			break;
 		case '9':
 			params->no_aa = 1;
@@ -1030,31 +1020,25 @@ static struct common_params
 		case '\5':
 			retval = actions_parse(&params->common.threshold_actions, optarg,
 					       "timerlat_trace.txt");
-			if (retval) {
-				err_msg("Invalid action %s\n", optarg);
-				exit(EXIT_FAILURE);
-			}
+			if (retval)
+				fatal("Invalid action %s", optarg);
 			break;
 		case '\6':
 			retval = actions_parse(&params->common.end_actions, optarg,
 					       "timerlat_trace.txt");
-			if (retval) {
-				err_msg("Invalid action %s\n", optarg);
-				exit(EXIT_FAILURE);
-			}
+			if (retval)
+				fatal("Invalid action %s", optarg);
 			break;
 		default:
-			timerlat_hist_usage("Invalid option");
+			fatal("Invalid option");
 		}
 	}
 
 	if (trace_output)
 		actions_add_trace_output(&params->common.threshold_actions, trace_output);
 
-	if (geteuid()) {
-		err_msg("rtla needs root permission\n");
-		exit(EXIT_FAILURE);
-	}
+	if (geteuid())
+		fatal("rtla needs root permission");
 
 	if (params->common.hist.no_irq && params->common.hist.no_thread)
 		timerlat_hist_usage("no-irq and no-thread set, there is nothing to do here");
diff --git a/tools/tracing/rtla/src/timerlat_top.c b/tools/tracing/rtla/src/timerlat_top.c
index 82e227d27af7..9664b8af727e 100644
--- a/tools/tracing/rtla/src/timerlat_top.c
+++ b/tools/tracing/rtla/src/timerlat_top.c
@@ -666,10 +666,8 @@ static struct common_params
 			break;
 		case 'e':
 			tevent = trace_event_alloc(optarg);
-			if (!tevent) {
-				err_msg("Error alloc trace event");
-				exit(EXIT_FAILURE);
-			}
+			if (!tevent)
+				fatal("Error alloc trace event");
 
 			if (params->common.events)
 				tevent->next = params->common.events;
@@ -682,10 +680,8 @@ static struct common_params
 		case 'H':
 			params->common.hk_cpus = 1;
 			retval = parse_cpu_set(optarg, &params->common.hk_cpu_set);
-			if (retval) {
-				err_msg("Error parsing house keeping CPUs\n");
-				exit(EXIT_FAILURE);
-			}
+			if (retval)
+				fatal("Error parsing house keeping CPUs");
 			break;
 		case 'i':
 			params->common.stop_us = get_llong_from_str(optarg);
@@ -736,10 +732,8 @@ static struct common_params
 		case '0': /* trigger */
 			if (params->common.events) {
 				retval = trace_event_add_trigger(params->common.events, optarg);
-				if (retval) {
-					err_msg("Error adding trigger %s\n", optarg);
-					exit(EXIT_FAILURE);
-				}
+				if (retval)
+					fatal("Error adding trigger %s", optarg);
 			} else {
 				timerlat_top_usage("--trigger requires a previous -e\n");
 			}
@@ -747,20 +741,16 @@ static struct common_params
 		case '1': /* filter */
 			if (params->common.events) {
 				retval = trace_event_add_filter(params->common.events, optarg);
-				if (retval) {
-					err_msg("Error adding filter %s\n", optarg);
-					exit(EXIT_FAILURE);
-				}
+				if (retval)
+					fatal("Error adding filter %s", optarg);
 			} else {
 				timerlat_top_usage("--filter requires a previous -e\n");
 			}
 			break;
 		case '2': /* dma-latency */
 			params->dma_latency = get_llong_from_str(optarg);
-			if (params->dma_latency < 0 || params->dma_latency > 10000) {
-				err_msg("--dma-latency needs to be >= 0 and < 10000");
-				exit(EXIT_FAILURE);
-			}
+			if (params->dma_latency < 0 || params->dma_latency > 10000)
+				fatal("--dma-latency needs to be >= 0 and < 10000");
 			break;
 		case '3': /* no-aa */
 			params->no_aa = 1;
@@ -780,18 +770,14 @@ static struct common_params
 		case '9':
 			retval = actions_parse(&params->common.threshold_actions, optarg,
 					       "timerlat_trace.txt");
-			if (retval) {
-				err_msg("Invalid action %s\n", optarg);
-				exit(EXIT_FAILURE);
-			}
+			if (retval)
+				fatal("Invalid action %s", optarg);
 			break;
 		case '\1':
 			retval = actions_parse(&params->common.end_actions, optarg,
 					       "timerlat_trace.txt");
-			if (retval) {
-				err_msg("Invalid action %s\n", optarg);
-				exit(EXIT_FAILURE);
-			}
+			if (retval)
+				fatal("Invalid action %s", optarg);
 			break;
 		default:
 			timerlat_top_usage("Invalid option");
@@ -801,10 +787,8 @@ static struct common_params
 	if (trace_output)
 		actions_add_trace_output(&params->common.threshold_actions, trace_output);
 
-	if (geteuid()) {
-		err_msg("rtla needs root permission\n");
-		exit(EXIT_FAILURE);
-	}
+	if (geteuid())
+		fatal("rtla needs root permission");
 
 	/*
 	 * Auto analysis only happens if stop tracing, thus:
diff --git a/tools/tracing/rtla/src/timerlat_u.c b/tools/tracing/rtla/src/timerlat_u.c
index 01dbf9a6b5a5..ce68e39d25fd 100644
--- a/tools/tracing/rtla/src/timerlat_u.c
+++ b/tools/tracing/rtla/src/timerlat_u.c
@@ -51,10 +51,8 @@ static int timerlat_u_main(int cpu, struct timerlat_u_params *params)
 
 	if (!params->sched_param) {
 		retval = sched_setscheduler(0, SCHED_FIFO, &sp);
-		if (retval < 0) {
-			err_msg("Error setting timerlat u default priority: %s\n", strerror(errno));
-			exit(1);
-		}
+		if (retval < 0)
+			fatal("Error setting timerlat u default priority: %s", strerror(errno));
 	} else {
 		retval = __set_sched_attr(getpid(), params->sched_param);
 		if (retval) {
@@ -78,10 +76,8 @@ static int timerlat_u_main(int cpu, struct timerlat_u_params *params)
 	snprintf(buffer, sizeof(buffer), "osnoise/per_cpu/cpu%d/timerlat_fd", cpu);
 
 	timerlat_fd = tracefs_instance_file_open(NULL, buffer, O_RDONLY);
-	if (timerlat_fd < 0) {
-		err_msg("Error opening %s:%s\n", buffer, strerror(errno));
-		exit(1);
-	}
+	if (timerlat_fd < 0)
+		fatal("Error opening %s:%s", buffer, strerror(errno));
 
 	debug_msg("User-space timerlat pid %d on cpu %d\n", gettid(), cpu);
 
diff --git a/tools/tracing/rtla/src/utils.c b/tools/tracing/rtla/src/utils.c
index d6ab15dcb490..54334c676a22 100644
--- a/tools/tracing/rtla/src/utils.c
+++ b/tools/tracing/rtla/src/utils.c
@@ -57,6 +57,21 @@ void debug_msg(const char *fmt, ...)
 }
 
 /*
+ * fatal - print an error message and EOL to stderr and exit with ERROR
+ */
+void fatal(const char *fmt, ...)
+{
+	va_list ap;
+
+	va_start(ap, fmt);
+	vfprintf(stderr, fmt, ap);
+	va_end(ap);
+	fprintf(stderr, "\n");
+
+	exit(ERROR);
+}
+
+/*
  * get_llong_from_str - get a long long int from a string
  */
 long long get_llong_from_str(char *start)
diff --git a/tools/tracing/rtla/src/utils.h b/tools/tracing/rtla/src/utils.h
index a2a6f89f342d..1be095f9a7e6 100644
--- a/tools/tracing/rtla/src/utils.h
+++ b/tools/tracing/rtla/src/utils.h
@@ -19,6 +19,7 @@
 extern int config_debug;
 void debug_msg(const char *fmt, ...);
 void err_msg(const char *fmt, ...);
+void fatal(const char *fmt, ...);
 
 long parse_seconds_duration(char *val);
 void get_duration(time_t start_time, char *output, int output_size);