Re: [PATCH v8 3/5] perf config: Reimplement perf_config() using perf_config_set__iter()

[Arnaldo Carvalho de Melo <acme@kernel.org>]

Em Wed, Jun 08, 2016 at 09:36:51PM +0900, Taeung Song escreveu:
> Many sub-commands use perf_config() so
> everytime perf_config() is called, perf_config() always read config files.
> (i.e. user config '~/.perfconfig' and system config '$(sysconfdir)/perfconfig')
> 
> But we need to use the config set that already contains all config
> key-value pairs to avoid this repetitive work reading the config files
> in perf_config(). (the config set mean a global variable 'config_set')
> 
> In other words, if new perf_config() is called,
> only first time 'config_set' is initialized collecting all configs
> from the config files and it work with perf_config_set__iter().
> And free the config set after a sub-command work at run_builtin().
> 
> If we do, 'config_set' can be reused wherever using perf_config()
> and a feature of old perf_config() is the same as new perf_config() work
> without the repetitive work that read the config files.
> 
> Cc: Namhyung Kim <namhyung@kernel.org>
> Cc: Jiri Olsa <jolsa@redhat.com>
> Cc: Wang Nan <wangnan0@huawei.com>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Ingo Molnar <mingo@redhat.com>
> Cc: Masami Hiramatsu <mhiramat@kernel.org>
> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
> Signed-off-by: Taeung Song <treeze.taeung@gmail.com>
> ---
>  tools/perf/builtin-config.c |  4 +++
>  tools/perf/perf.c           |  1 +
>  tools/perf/util/config.c    | 87 ++++++++++++++++++++++-----------------------
>  tools/perf/util/config.h    |  1 +
>  4 files changed, 48 insertions(+), 45 deletions(-)
> 
> diff --git a/tools/perf/builtin-config.c b/tools/perf/builtin-config.c
> index fe1b77f..cfd1036 100644
> --- a/tools/perf/builtin-config.c
> +++ b/tools/perf/builtin-config.c
> @@ -80,6 +80,10 @@ int cmd_config(int argc, const char **argv, const char *prefix __maybe_unused)
>  	else if (use_user_config)
>  		config_exclusive_filename = user_config;
>  
> +	/*
> +	 * At only 'config' sub-command, individually use the config set
> +	 * because of reinitializing with options config file location.
> +	 */
>  	set = perf_config_set__new();
>  	if (!set) {
>  		ret = -1;
> diff --git a/tools/perf/perf.c b/tools/perf/perf.c
> index 15982ce..fe2ab7c 100644
> --- a/tools/perf/perf.c
> +++ b/tools/perf/perf.c
> @@ -391,6 +391,7 @@ static int run_builtin(struct cmd_struct *p, int argc, const char **argv)
>  
>  	perf_env__set_cmdline(&perf_env, argc, argv);
>  	status = p->fn(argc, argv, prefix);
> +	perf_config_set__delete(config_set);
>  	exit_browser(status);
>  	perf_env__exit(&perf_env);
>  	bpf__clear();
> diff --git a/tools/perf/util/config.c b/tools/perf/util/config.c
> index 31e09a4..72db134 100644
> --- a/tools/perf/util/config.c
> +++ b/tools/perf/util/config.c
> @@ -28,6 +28,7 @@ static int config_linenr;
>  static int config_file_eof;
>  
>  const char *config_exclusive_filename;
> +struct perf_config_set *config_set;
>  
>  static int get_next_char(void)
>  {
> @@ -478,51 +479,6 @@ static int perf_config_global(void)
>  	return !perf_env_bool("PERF_CONFIG_NOGLOBAL", 0);
>  }
>  
> -int perf_config(config_fn_t fn, void *data)
> -{
> -	int ret = -1;
> -	const char *home = NULL;
> -
> -	/* Setting $PERF_CONFIG makes perf read _only_ the given config file. */
> -	if (config_exclusive_filename)
> -		return perf_config_from_file(fn, config_exclusive_filename, data);
> -	if (perf_config_system() && !access(perf_etc_perfconfig(), R_OK)) {
> -		if (perf_config_from_file(fn, perf_etc_perfconfig(), data) < 0)
> -			goto out;
> -	}
> -
> -	home = getenv("HOME");
> -	if (perf_config_global() && home) {
> -		char *user_config = strdup(mkpath("%s/.perfconfig", home));
> -		struct stat st;
> -
> -		if (user_config == NULL) {
> -			warning("Not enough memory to process %s/.perfconfig, "
> -				"ignoring it.", home);
> -			goto out;
> -		}
> -
> -		if (stat(user_config, &st) < 0)
> -			goto out_free;
> -
> -		if (st.st_uid && (st.st_uid != geteuid())) {
> -			warning("File %s not owned by current user or root, "
> -				"ignoring it.", user_config);
> -			goto out_free;
> -		}
> -
> -		if (!st.st_size)
> -			goto out_free;
> -
> -		ret = perf_config_from_file(fn, user_config, data);
> -
> -out_free:
> -		free(user_config);
> -	}
> -out:
> -	return ret;
> -}
> -
>  static struct perf_config_section *find_section(struct list_head *sections,
>  						const char *section_name)
>  {
> @@ -706,6 +662,47 @@ struct perf_config_set *perf_config_set__new(void)
>  	return set;
>  }
>  
> +static int perf_config_set__iter(struct perf_config_set *set, config_fn_t fn, void *data)
> +{
> +	struct perf_config_section *section;
> +	struct perf_config_item *item;
> +	struct list_head *sections;
> +	char key[BUFSIZ];
> +
> +	if (set == NULL)
> +		return -1;
> +
> +	sections = &set->sections;
> +	if (list_empty(sections))
> +		return -1;
> +
> +	list_for_each_entry(section, sections, node) {
> +		list_for_each_entry(item, &section->items, node) {
> +			char *value = item->value;
> +
> +			if (value) {
> +				scnprintf(key, sizeof(key), "%s.%s",
> +					  section->name, item->name);
> +				if (fn(key, value, data) < 0) {
> +					pr_err("Error: wrong config key-value pair %s=%s\n",
> +					       key, value);
> +					return -1;
> +				}
> +			}
> +		}
> +	}
> +
> +	return 0;
> +}
> +
> +int perf_config(config_fn_t fn, void *data)
> +{
> +	if (config_set == NULL)
> +		config_set = perf_config_set__new();
> +
> +	return perf_config_set__iter(config_set, fn, data);
> +}
> +

Try not using those iter + callback things, use something like this
instead:

	perf_config_set__for_each(pos, config_set)
		fn(pos, data)

I.e. use the list.h model. At some point this perf_config() function
should probably die, I guess.

- Arnaldo