[PATCH v16 8/8] perf config: Add a option 'remove' to perf-config

[Taeung Song]

A option 'remove' is to remove specific config variables.
For the syntax examples,

    # perf config [<file-option>] -r | --remove [section.name ...]

Cc: Namhyung Kim <namhy...@kernel.org>
Cc: Jiri Olsa <jo...@kernel.org>
Signed-off-by: Taeung Song <treeze.tae...@gmail.com>
---
 tools/perf/Documentation/perf-config.txt |  6 ++++++
 tools/perf/builtin-config.c              | 37 ++++++++++++++++++++++++++++++--
 2 files changed, 41 insertions(+), 2 deletions(-)

diff --git a/tools/perf/Documentation/perf-config.txt 
b/tools/perf/Documentation/perf-config.txt
index 52fdb4b..89c1ceb 100644
--- a/tools/perf/Documentation/perf-config.txt
+++ b/tools/perf/Documentation/perf-config.txt
@@ -15,6 +15,8 @@ or
 'perf config' [<file-option>] -a | --list-all
 or
 'perf config' [<file-option>] -k | --skel
+or
+'perf config' [<file-option>] -r | --remove [section.name ...]
 
 DESCRIPTION
 -----------
@@ -47,6 +49,10 @@ OPTIONS
 --verbose::
        Be more verbose. (show config description)
 
+-r::
+--remove::
+       Remove specific config variables.
+
 CONFIGURATION FILE
 ------------------
 
diff --git a/tools/perf/builtin-config.c b/tools/perf/builtin-config.c
index bad8182..7ba842c 100644
--- a/tools/perf/builtin-config.c
+++ b/tools/perf/builtin-config.c
@@ -23,7 +23,8 @@ static const char * const config_usage[] = {
 enum actions {
        ACTION_LIST = 1,
        ACTION_LIST_ALL,
-       ACTION_SKEL
+       ACTION_SKEL,
+       ACTION_REMOVE
 } actions;
 
 static struct option config_options[] = {
@@ -35,6 +36,8 @@ static struct option config_options[] = {
        OPT_SET_UINT('k', "skel", &actions,
                     "produce an skeleton with the possible"
                     " config variables", ACTION_SKEL),
+       OPT_SET_UINT('r', "remove", &actions,
+                    "remove specific variables: [section.name ...]", 
ACTION_REMOVE),
        OPT_INCR('v', "verbose", &verbose, "Be more verbose"
                 " (show config description)"),
        OPT_BOOLEAN(0, "system", &use_system_config, "use system config file"),
@@ -499,7 +502,13 @@ static int set_config(struct list_head *sections, const 
char *config_file_name,
        struct config_element *element = NULL;
 
        find_config(sections, &section, &element, section_name, name);
-       if (value != NULL) {
+       if (!value) {
+               /* value == NULL means remove the variable */
+               if (section && element) {
+                       free(element->value);
+                       element->value = NULL;
+               }
+       } else {
                value = normalize_value(section_name, name, value);
 
                /* if there isn't existent section, add a new section */
@@ -663,6 +672,7 @@ int cmd_config(int argc, const char **argv, const char 
*prefix __maybe_unused)
 
        set_option_flag(config_options, 'l', "list", PARSE_OPT_EXCLUSIVE);
        set_option_flag(config_options, 'a', "list-all", PARSE_OPT_EXCLUSIVE);
+       set_option_flag(config_options, 'r', "remove", PARSE_OPT_EXCLUSIVE);
 
        argc = parse_options(argc, argv, config_options, config_usage,
                             PARSE_OPT_STOP_AT_NON_OPTION);
@@ -692,6 +702,29 @@ int cmd_config(int argc, const char **argv, const char 
*prefix __maybe_unused)
        }
 
        switch (actions) {
+       case ACTION_REMOVE:
+               if (argc) {
+                       for (i = 0; argv[i]; i++) {
+                               if (!use_system_config && !use_user_config) {
+                                       ret = 
perf_configset_with_option(set_config,
+                                                                        
&system_sections,
+                                                                        
system_config,
+                                                                        
argv[i], NULL);
+                                       ret = 
perf_configset_with_option(set_config,
+                                                                        
&user_sections,
+                                                                        
user_config,
+                                                                        
argv[i], NULL);
+                               } else
+                                       ret = 
perf_configset_with_option(set_config, sections,
+                                                                        
config_exclusive_filename,
+                                                                        
argv[i], NULL);
+                       }
+               } else {
+                       pr_err("Error: Missing arguments\n");
+                       parse_options_usage(config_usage, config_options, "r", 
1);
+                       return -1;
+               }
+               break;
        case ACTION_SKEL:
                if (argc)
                        parse_options_usage(config_usage, config_options, "k", 
1);
-- 
2.5.0