[PATCH v1] tools/rtla: Generate optstring from long options

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

getopt_long() processes short and long options independently.
RTLA, like the majority of applications, uses both short and long
variants for each logical option.

Since the val member of struct option holds the letter of the short
variant, the string of short options can be reconstructed from the
array of long options.

Add getopt_auto() to generate optstring from an array of long options,
eliminating the need to maintain separate short option strings.

Signed-off-by: Costa Shulyupin <costa.shul@redhat.com>
---
 tools/tracing/rtla/src/common.c        | 32 +++++++++++++++++++++++++-
 tools/tracing/rtla/src/common.h        |  2 ++
 tools/tracing/rtla/src/osnoise_hist.c  |  3 +--
 tools/tracing/rtla/src/osnoise_top.c   |  3 +--
 tools/tracing/rtla/src/timerlat_hist.c |  3 +--
 tools/tracing/rtla/src/timerlat_top.c  |  3 +--
 6 files changed, 37 insertions(+), 9 deletions(-)

diff --git a/tools/tracing/rtla/src/common.c b/tools/tracing/rtla/src/common.c
index ceff76a62a30..f310b0d59ad3 100644
--- a/tools/tracing/rtla/src/common.c
+++ b/tools/tracing/rtla/src/common.c
@@ -39,6 +39,36 @@ static void set_signals(struct common_params *params)
 	}
 }
 
+/*
+ * getopt_auto - auto-generates optstring from long_options
+ */
+int getopt_auto(int argc, char **argv, const struct option *long_opts)
+{
+	char opts[256];
+	int n = 0;
+
+	for (int i = 0; long_opts[i].name; i++) {
+		if (long_opts[i].val < 32 || long_opts[i].val > 127)
+			continue;
+
+		if (n + 4 >= sizeof(opts))
+			fatal("optstring buffer overflow");
+
+		opts[n++] = long_opts[i].val;
+
+		if (long_opts[i].has_arg == required_argument)
+			opts[n++] = ':';
+		else if (long_opts[i].has_arg == optional_argument) {
+			opts[n++] = ':';
+			opts[n++] = ':';
+		}
+	}
+
+	opts[n] = '\0';
+
+	return getopt_long(argc, argv, opts, long_opts, NULL);
+}
+
 /*
  * common_parse_options - parse common command line options
  *
@@ -69,7 +99,7 @@ int common_parse_options(int argc, char **argv, struct common_params *common)
 	};
 
 	opterr = 0;
-	c = getopt_long(argc, argv, "c:C::Dd:e:H:P:", long_options, NULL);
+	c = getopt_auto(argc, argv, long_options);
 	opterr = 1;
 
 	switch (c) {
diff --git a/tools/tracing/rtla/src/common.h b/tools/tracing/rtla/src/common.h
index 7602c5593ef5..d4b3715700be 100644
--- a/tools/tracing/rtla/src/common.h
+++ b/tools/tracing/rtla/src/common.h
@@ -1,6 +1,7 @@
 /* SPDX-License-Identifier: GPL-2.0 */
 #pragma once
 
+#include <getopt.h>
 #include "actions.h"
 #include "timerlat_u.h"
 #include "trace.h"
@@ -156,6 +157,7 @@ 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 getopt_auto(int argc, char **argv, const struct option *long_opts);
 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);
diff --git a/tools/tracing/rtla/src/osnoise_hist.c b/tools/tracing/rtla/src/osnoise_hist.c
index 9d70ea34807f..5c863e7aad28 100644
--- a/tools/tracing/rtla/src/osnoise_hist.c
+++ b/tools/tracing/rtla/src/osnoise_hist.c
@@ -506,8 +506,7 @@ static struct common_params
 		if (common_parse_options(argc, argv, &params->common))
 			continue;
 
-		c = getopt_long(argc, argv, "a:b:E:hp:r:s:S:t::T:01234:5:6:7:",
-				 long_options, NULL);
+		c = getopt_auto(argc, argv, long_options);
 
 		/* detect the end of the options. */
 		if (c == -1)
diff --git a/tools/tracing/rtla/src/osnoise_top.c b/tools/tracing/rtla/src/osnoise_top.c
index d54d47947fb4..b7aed40fd216 100644
--- a/tools/tracing/rtla/src/osnoise_top.c
+++ b/tools/tracing/rtla/src/osnoise_top.c
@@ -358,8 +358,7 @@ struct common_params *osnoise_top_parse_args(int argc, char **argv)
 		if (common_parse_options(argc, argv, &params->common))
 			continue;
 
-		c = getopt_long(argc, argv, "a:hp:qr:s:S:t::T:0:1:2:3:",
-				 long_options, NULL);
+		c = getopt_auto(argc, argv, long_options);
 
 		/* Detect the end of the options. */
 		if (c == -1)
diff --git a/tools/tracing/rtla/src/timerlat_hist.c b/tools/tracing/rtla/src/timerlat_hist.c
index 4e8c38a61197..096de8ba3efb 100644
--- a/tools/tracing/rtla/src/timerlat_hist.c
+++ b/tools/tracing/rtla/src/timerlat_hist.c
@@ -825,8 +825,7 @@ static struct common_params
 		if (common_parse_options(argc, argv, &params->common))
 			continue;
 
-		c = getopt_long(argc, argv, "a:b:E:hi:knp:s:t::T:uU0123456:7:8:9\1\2:\3:",
-				 long_options, NULL);
+		c = getopt_auto(argc, argv, long_options);
 
 		/* detect the end of the options. */
 		if (c == -1)
diff --git a/tools/tracing/rtla/src/timerlat_top.c b/tools/tracing/rtla/src/timerlat_top.c
index 284b74773c2b..27c14aa71a8b 100644
--- a/tools/tracing/rtla/src/timerlat_top.c
+++ b/tools/tracing/rtla/src/timerlat_top.c
@@ -588,8 +588,7 @@ static struct common_params
 		if (common_parse_options(argc, argv, &params->common))
 			continue;
 
-		c = getopt_long(argc, argv, "a:hi:knp:qs:t::T:uU0:1:2:345:6:7:",
-				 long_options, NULL);
+		c = getopt_auto(argc, argv, long_options);
 
 		/* detect the end of the options. */
 		if (c == -1)
-- 
2.52.0