[PATCH v1 1/5] tools/rtla: Add fatal() and replace error handling pattern

[Costa Shulyupin <costa.shul@redhat.com>]

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>
---
 tools/tracing/rtla/src/osnoise_hist.c  | 42 ++++++++--------------
 tools/tracing/rtla/src/osnoise_top.c   | 42 ++++++++--------------
 tools/tracing/rtla/src/timerlat_hist.c | 50 +++++++++-----------------
 tools/tracing/rtla/src/timerlat_top.c  | 48 +++++++++----------------
 tools/tracing/rtla/src/timerlat_u.c    | 12 +++----
 tools/tracing/rtla/src/utils.c         | 14 ++++++++
 tools/tracing/rtla/src/utils.h         |  1 +
 7 files changed, 80 insertions(+), 129 deletions(-)

diff --git a/tools/tracing/rtla/src/osnoise_hist.c b/tools/tracing/rtla/src/osnoise_hist.c
index dffb6d0a98d7..43c323521f55 100644
--- a/tools/tracing/rtla/src/osnoise_hist.c
+++ b/tools/tracing/rtla/src/osnoise_hist.c
@@ -592,10 +592,8 @@ 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;
@@ -615,10 +613,8 @@ 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\n");
 			break;
 		case 'p':
 			params->period = get_llong_from_str(optarg);
@@ -671,10 +667,8 @@ 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\n", optarg);
 			} else {
 				osnoise_hist_usage("--trigger requires a previous -e\n");
 			}
@@ -682,10 +676,8 @@ 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\n", optarg);
 			} else {
 				osnoise_hist_usage("--filter requires a previous -e\n");
 			}
@@ -699,18 +691,14 @@ 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\n", 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\n", optarg);
 			break;
 		default:
 			osnoise_hist_usage("Invalid option");
@@ -720,10 +708,8 @@ 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\n");
 
 	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 95418f7ecc96..43fb50b5d936 100644
--- a/tools/tracing/rtla/src/osnoise_top.c
+++ b/tools/tracing/rtla/src/osnoise_top.c
@@ -426,10 +426,8 @@ 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;
@@ -443,10 +441,8 @@ 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\n");
 			break;
 		case 'p':
 			params->period = get_llong_from_str(optarg);
@@ -490,10 +486,8 @@ 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\n", optarg);
 			} else {
 				osnoise_top_usage(params, "--trigger requires a previous -e\n");
 			}
@@ -501,10 +495,8 @@ 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\n", optarg);
 			} else {
 				osnoise_top_usage(params, "--filter requires a previous -e\n");
 			}
@@ -518,18 +510,14 @@ 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\n", 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\n", optarg);
 			break;
 		default:
 			osnoise_top_usage(params, "Invalid option");
@@ -539,10 +527,8 @@ 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\n");
 
 	return &params->common;
 }
diff --git a/tools/tracing/rtla/src/timerlat_hist.c b/tools/tracing/rtla/src/timerlat_hist.c
index 606c1688057b..6504556be5e4 100644
--- a/tools/tracing/rtla/src/timerlat_hist.c
+++ b/tools/tracing/rtla/src/timerlat_hist.c
@@ -913,10 +913,8 @@ 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;
@@ -936,10 +934,8 @@ 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\n");
 			break;
 		case 'i':
 			params->common.stop_us = get_llong_from_str(optarg);
@@ -1005,10 +1001,8 @@ 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\n", optarg);
 			} else {
 				timerlat_hist_usage("--trigger requires a previous -e\n");
 			}
@@ -1016,20 +1010,16 @@ 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\n", 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;
@@ -1049,31 +1039,25 @@ 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\n", 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\n", optarg);
 			break;
 		default:
-			timerlat_hist_usage("Invalid option");
+			fatal("Invalid option\n");
 		}
 	}
 
 	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\n");
 
 	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 fc479a0dcb59..03ecc38d0719 100644
--- a/tools/tracing/rtla/src/timerlat_top.c
+++ b/tools/tracing/rtla/src/timerlat_top.c
@@ -671,10 +671,8 @@ 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;
@@ -687,10 +685,8 @@ 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\n");
 			break;
 		case 'i':
 			params->common.stop_us = get_llong_from_str(optarg);
@@ -741,10 +737,8 @@ 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\n", optarg);
 			} else {
 				timerlat_top_usage("--trigger requires a previous -e\n");
 			}
@@ -752,20 +746,16 @@ 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\n", 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;
@@ -785,18 +775,14 @@ 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\n", 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\n", optarg);
 			break;
 		default:
 			timerlat_top_usage("Invalid option");
@@ -806,10 +792,8 @@ 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\n");
 
 	/*
 	 * 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..2f85c242e1d5 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\n", 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\n", 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..bf3662313cde 100644
--- a/tools/tracing/rtla/src/utils.c
+++ b/tools/tracing/rtla/src/utils.c
@@ -38,6 +38,20 @@ void err_msg(const char *fmt, ...)
 	fprintf(stderr, "%s", message);
 }
 
+/*
+ * fatal - print an error message 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);
+
+	exit(ERROR);
+}
+
 /*
  * debug_msg - print a debug message to stderr if debug is set
  */
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);
-- 
2.51.0