perf tools: Add general function to parse sublevel options

This factors out a general function perf_parse_sublevel_options() to
parse sublevel options. The 'sublevel' options is something like the
'--debug' options which allow more sublevel options.

Signed-off-by: Changbin Du <changbin.du@gmail.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Link: http://lore.kernel.org/lkml/20200808023141.14227-8-changbin.du@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/Build

@@ -117,6 +117,7 @@ endif
 perf-y += parse-branch-options.o
 perf-y += dump-insn.o
 perf-y += parse-regs-options.o
+perf-y += parse-sublevel-options.o
 perf-y += term.o
 perf-y += help-unknown-cmd.o
 perf-y += mem-events.o

tools/perf/util/debug.c

@@ -20,6 +20,7 @@
 #include "target.h"
 #include "ui/helpline.h"
 #include "ui/ui.h"
+#include "util/parse-sublevel-options.h"
 
 #include <linux/ctype.h>
 
@@ -173,65 +174,37 @@ void trace_event(union perf_event *event)
 		     trace_event_printer, event);
 }
 
-static struct debug_variable {
+static struct sublevel_option debug_opts[] = {
-	const char *name;
+	{ .name = "verbose",		.value_ptr = &verbose },
-	int *ptr;
+	{ .name = "ordered-events",	.value_ptr = &debug_ordered_events},
-} debug_variables[] = {
+	{ .name = "stderr",		.value_ptr = &redirect_to_stderr},
-	{ .name = "verbose",		.ptr = &verbose },
+	{ .name = "data-convert",	.value_ptr = &debug_data_convert },
-	{ .name = "ordered-events",	.ptr = &debug_ordered_events},
+	{ .name = "perf-event-open",	.value_ptr = &debug_peo_args },
-	{ .name = "stderr",		.ptr = &redirect_to_stderr},
-	{ .name = "data-convert",	.ptr = &debug_data_convert },
-	{ .name = "perf-event-open",	.ptr = &debug_peo_args },
 	{ .name = NULL, }
 };
 
 int perf_debug_option(const char *str)
 {
-	struct debug_variable *var = &debug_variables[0];
+	int ret;
-	char *vstr, *s = strdup(str);
-	int v = 1;
 
-	vstr = strchr(s, '=');
+	ret = perf_parse_sublevel_options(str, debug_opts);
-	if (vstr)
+	if (ret)
-		*vstr++ = 0;
+		return ret;
 
-	while (var->name) {
+	/* Allow only verbose value in range (0, 10), otherwise set 0. */
-		if (!strcmp(s, var->name))
+	verbose = (verbose < 0) || (verbose > 10) ? 0 : verbose;
-			break;
-		var++;
-	}
 
-	if (!var->name) {
-		pr_err("Unknown debug variable name '%s'\n", s);
-		free(s);
-		return -1;
-	}
-
-	if (vstr) {
-		v = atoi(vstr);
-		/*
-		 * Allow only values in range (0, 10),
-		 * otherwise set 0.
-		 */
-		v = (v < 0) || (v > 10) ? 0 : v;
-	}
-
-	if (quiet)
-		v = -1;
-
-	*var->ptr = v;
-	free(s);
 	return 0;
 }
 
 int perf_quiet_option(void)
 {
-	struct debug_variable *var = &debug_variables[0];
+	struct sublevel_option *opt = &debug_opts[0];
 
 	/* disable all debug messages */
-	while (var->name) {
+	while (opt->name) {
-		*var->ptr = -1;
+		*opt->value_ptr = -1;
-		var++;
+		opt++;
 	}
 
 	return 0;

tools/perf/util/parse-sublevel-options.c

@@ -0,0 +1,70 @@
+#include <stdlib.h>
+#include <stdint.h>
+#include <string.h>
+#include <stdio.h>
+
+#include "util/debug.h"
+#include "util/parse-sublevel-options.h"
+
+static int parse_one_sublevel_option(const char *str,
+				     struct sublevel_option *opts)
+{
+	struct sublevel_option *opt = opts;
+	char *vstr, *s = strdup(str);
+	int v = 1;
+
+	if (!s) {
+		pr_err("no memory\n");
+		return -1;
+	}
+
+	vstr = strchr(s, '=');
+	if (vstr)
+		*vstr++ = 0;
+
+	while (opt->name) {
+		if (!strcmp(s, opt->name))
+			break;
+		opt++;
+	}
+
+	if (!opt->name) {
+		pr_err("Unknown option name '%s'\n", s);
+		free(s);
+		return -1;
+	}
+
+	if (vstr)
+		v = atoi(vstr);
+
+	*opt->value_ptr = v;
+	free(s);
+	return 0;
+}
+
+/* parse options like --foo a=<n>,b,c... */
+int perf_parse_sublevel_options(const char *str, struct sublevel_option *opts)
+{
+	char *s = strdup(str);
+	char *p = NULL;
+	int ret;
+
+	if (!s) {
+		pr_err("no memory\n");
+		return -1;
+	}
+
+	p = strtok(s, ",");
+	while (p) {
+		ret = parse_one_sublevel_option(p, opts);
+		if (ret) {
+			free(s);
+			return ret;
+		}
+
+		p = strtok(NULL, ",");
+	}
+
+	free(s);
+	return 0;
+}

tools/perf/util/parse-sublevel-options.h

@@ -0,0 +1,11 @@
+#ifndef _PERF_PARSE_SUBLEVEL_OPTIONS_H
+#define _PERF_PARSE_SUBLEVEL_OPTIONS_H
+
+struct sublevel_option {
+	const char *name;
+	int *value_ptr;
+};
+
+int perf_parse_sublevel_options(const char *str, struct sublevel_option *opts);
+
+#endif