tools/rtla: Add common_parse_options()

Each rtla tool duplicates parsing of many common options. This creates
maintenance overhead and risks inconsistencies when updating these
options.

Add common_parse_options() to centralize parsing of options used across
all tools.

Common options to be migrated in future patches.

Changes since v1:
- restore opterr

Signed-off-by: Costa Shulyupin <costa.shul@redhat.com>
Link: https://lore.kernel.org/r/20251209100047.2692515-1-costa.shul@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>

tools/tracing/rtla/src/common.c

@@ -6,6 +6,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
+#include <getopt.h>
 #include "common.h"
 
 struct trace_instance *trace_inst;
@@ -38,6 +39,40 @@ static void set_signals(struct common_params *params)
 	}
 }
 
+/*
+ * common_parse_options - parse common command line options
+ *
+ * @argc: argument count
+ * @argv: argument vector
+ * @common: common parameters structure
+ *
+ * Parse command line options that are common to all rtla tools.
+ *
+ * Returns: non zero if a common option was parsed, or 0
+ * if the option should be handled by tool-specific parsing.
+ */
+int common_parse_options(int argc, char **argv, struct common_params *common)
+{
+	int saved_state = optind;
+	int c;
+
+	static struct option long_options[] = {
+		{0, 0, 0, 0}
+	};
+
+	opterr = 0;
+	c = getopt_long(argc, argv, "", long_options, NULL);
+	opterr = 1;
+
+	switch (c) {
+	default:
+		optind = saved_state;
+		return 0;
+	}
+
+	return c;
+}
+
 /*
  * common_apply_config - apply common configs to the initialized tool
  */

tools/tracing/rtla/src/common.h

@@ -156,6 +156,7 @@ int osnoise_set_stop_us(struct osnoise_context *context, long long stop_us);
 int osnoise_set_stop_total_us(struct osnoise_context *context,
 			      long long stop_total_us);
 
+int common_parse_options(int argc, char **argv, struct common_params *common);
 int common_apply_config(struct osnoise_tool *tool, struct common_params *params);
 int top_main_loop(struct osnoise_tool *tool);
 int hist_main_loop(struct osnoise_tool *tool);

tools/tracing/rtla/src/osnoise_hist.c

@@ -512,6 +512,9 @@ static struct common_params
 			{0, 0, 0, 0}
 		};
 
+		if (common_parse_options(argc, argv, &params->common))
+			continue;
+
 		c = getopt_long(argc, argv, "a:c:C::b:d:e:E:DhH:p:P:r:s:S:t::T:01234:5:6:7:",
 				 long_options, NULL);
 

tools/tracing/rtla/src/osnoise_top.c

@@ -363,6 +363,9 @@ struct common_params *osnoise_top_parse_args(int argc, char **argv)
 			{0, 0, 0, 0}
 		};
 
+		if (common_parse_options(argc, argv, &params->common))
+			continue;
+
 		c = getopt_long(argc, argv, "a:c:C::d:De:hH:p:P:qr:s:S:t::T:0:1:2:3:",
 				 long_options, NULL);
 

tools/tracing/rtla/src/timerlat_hist.c

@@ -830,6 +830,9 @@ static struct common_params
 			{0, 0, 0, 0}
 		};
 
+		if (common_parse_options(argc, argv, &params->common))
+			continue;
+
 		c = getopt_long(argc, argv, "a:c:C::b:d:e:E:DhH:i:knp:P:s:t::T:uU0123456:7:8:9\1\2:\3:",
 				 long_options, NULL);
 

tools/tracing/rtla/src/timerlat_top.c

@@ -594,6 +594,9 @@ static struct common_params
 			{0, 0, 0, 0}
 		};
 
+		if (common_parse_options(argc, argv, &params->common))
+			continue;
+
 		c = getopt_long(argc, argv, "a:c:C::d:De:hH:i:knp:P:qs:t::T:uU0:1:2:345:6:7:",
 				 long_options, NULL);