Re: [PATCH v5 7/8] perf hists browser: Add option for runtime switching perf data file

Arnaldo Carvalho de Melo
2012-10-29T14:08:22Z

Em Tue, Oct 30, 2012 at 11:56:08AM +0800, Feng Tang escreveu:
> + pwd_dir = opendir(pwd);
> + if (!pwd_dir)
> + return ret;
> +
> + memset(options, 0, sizeof(options));
> + memset(options, 0, sizeof(abs_path));
> +
> + while ((dent = readdir(pwd_dir))) {
> + char path[PATH_MAX];
> + u64 magic;
> + char *name = dent->d_name;
> + FILE *file;
> +
> + if (!(dent->d_type == DT_REG))
> + continue;
> +
> + snprintf(path, PATH_MAX, "%s/%s", pwd, name);
> +
> + file = fopen(path, "r");
> + if (!file)
> + continue;
> +
> + if (fread(&magic, 1, 8, file) < 8)
> + goto close_file_and_continue;
> +
> + if (is_perf_magic(magic)) {
> + options[nr_options] = strdup(name);
> + if (!options[nr_options])
> + goto close_file_and_continue;

Silently not offering a valid file? At this point I think you should
warn the user and bail out.

> +
> + abs_path[nr_options] = strdup(path);
> + if (!abs_path[nr_options]) {
> + free(options[nr_options]);
> + goto close_file_and_continue;
> + }
> +
> + nr_options++;
> + }
> +
> +close_file_and_continue:
> + fclose(file);
> + if (nr_options >= 256)
> + break;

Why is this? At the very least a warning has to be given to the user
that way too many perf.data files are present, so only the first N are
in the menu.

> + }
> + closedir(pwd_dir);
> +
> + if (nr_options) {
> + choice = ui__popup_menu(nr_options, options);
> + if (choice < nr_options && choice >= 0) {
> + tmp = strdup(abs_path[choice]);
> + if (tmp) {
> + if (is_input_name_malloced)
> + free((void *)input_name);
> + input_name = tmp;
> + is_input_name_malloced = true;
> + ret = 0;
> + }

Here you return an error, but will the user get any warning on the
caller of this function if it returns -1?

> + /* Switch to another data file */
> + else if (choice == switch_data) {
> +do_data_switch:
> + if (!switch_data_file()) {
> + key = K_SWITCH_INPUT_DATA;
> + break;
> + }
> + }

... no, so it will silently continue and the user will get confused.

> }
> out_free_stack:
> pstack__delete(fstack);
> @@ -1563,6 +1666,7 @@ browse_hists:
> "Do you really want to exit?"))
> continue;
> /* Fall thru */
> + case K_SWITCH_INPUT_DATA:
> case 'q':
> case CTRL('c'):
> goto out;
> diff --git a/tools/perf/ui/keysyms.h b/tools/perf/ui/keysyms.h
> index 809eca5..65092d5 100644
> --- a/tools/perf/ui/keysyms.h
> +++ b/tools/perf/ui/keysyms.h
> @@ -23,5 +23,6 @@
> #define K_TIMER -1
> #define K_ERROR -2
> #define K_RESIZE -3
> +#define K_SWITCH_INPUT_DATA -4
>
> #endif /* _PERF_KEYSYMS_H_ */
> --
> 1.7.9.5