GNU Linux-libre 4.19.211-gnu1
[releases.git] / tools / perf / builtin-help.c
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * builtin-help.c
4  *
5  * Builtin help command
6  */
7 #include "perf.h"
8 #include "util/config.h"
9 #include "builtin.h"
10 #include <subcmd/exec-cmd.h>
11 #include "common-cmds.h"
12 #include <subcmd/parse-options.h>
13 #include <subcmd/run-command.h>
14 #include <subcmd/help.h>
15 #include "util/debug.h"
16 #include <linux/kernel.h>
17 #include <errno.h>
18 #include <stdio.h>
19 #include <sys/types.h>
20 #include <sys/stat.h>
21 #include <unistd.h>
22
23 static struct man_viewer_list {
24         struct man_viewer_list *next;
25         char name[0];
26 } *man_viewer_list;
27
28 static struct man_viewer_info_list {
29         struct man_viewer_info_list *next;
30         const char *info;
31         char name[0];
32 } *man_viewer_info_list;
33
34 enum help_format {
35         HELP_FORMAT_NONE,
36         HELP_FORMAT_MAN,
37         HELP_FORMAT_INFO,
38         HELP_FORMAT_WEB,
39 };
40
41 static enum help_format parse_help_format(const char *format)
42 {
43         if (!strcmp(format, "man"))
44                 return HELP_FORMAT_MAN;
45         if (!strcmp(format, "info"))
46                 return HELP_FORMAT_INFO;
47         if (!strcmp(format, "web") || !strcmp(format, "html"))
48                 return HELP_FORMAT_WEB;
49
50         pr_err("unrecognized help format '%s'", format);
51         return HELP_FORMAT_NONE;
52 }
53
54 static const char *get_man_viewer_info(const char *name)
55 {
56         struct man_viewer_info_list *viewer;
57
58         for (viewer = man_viewer_info_list; viewer; viewer = viewer->next) {
59                 if (!strcasecmp(name, viewer->name))
60                         return viewer->info;
61         }
62         return NULL;
63 }
64
65 static int check_emacsclient_version(void)
66 {
67         struct strbuf buffer = STRBUF_INIT;
68         struct child_process ec_process;
69         const char *argv_ec[] = { "emacsclient", "--version", NULL };
70         int version;
71         int ret = -1;
72
73         /* emacsclient prints its version number on stderr */
74         memset(&ec_process, 0, sizeof(ec_process));
75         ec_process.argv = argv_ec;
76         ec_process.err = -1;
77         ec_process.stdout_to_stderr = 1;
78         if (start_command(&ec_process)) {
79                 fprintf(stderr, "Failed to start emacsclient.\n");
80                 return -1;
81         }
82         if (strbuf_read(&buffer, ec_process.err, 20) < 0) {
83                 fprintf(stderr, "Failed to read emacsclient version\n");
84                 goto out;
85         }
86         close(ec_process.err);
87
88         /*
89          * Don't bother checking return value, because "emacsclient --version"
90          * seems to always exits with code 1.
91          */
92         finish_command(&ec_process);
93
94         if (!strstarts(buffer.buf, "emacsclient")) {
95                 fprintf(stderr, "Failed to parse emacsclient version.\n");
96                 goto out;
97         }
98
99         version = atoi(buffer.buf + strlen("emacsclient"));
100
101         if (version < 22) {
102                 fprintf(stderr,
103                         "emacsclient version '%d' too old (< 22).\n",
104                         version);
105         } else
106                 ret = 0;
107 out:
108         strbuf_release(&buffer);
109         return ret;
110 }
111
112 static void exec_failed(const char *cmd)
113 {
114         char sbuf[STRERR_BUFSIZE];
115         pr_warning("failed to exec '%s': %s", cmd, str_error_r(errno, sbuf, sizeof(sbuf)));
116 }
117
118 static void exec_woman_emacs(const char *path, const char *page)
119 {
120         if (!check_emacsclient_version()) {
121                 /* This works only with emacsclient version >= 22. */
122                 char *man_page;
123
124                 if (!path)
125                         path = "emacsclient";
126                 if (asprintf(&man_page, "(woman \"%s\")", page) > 0) {
127                         execlp(path, "emacsclient", "-e", man_page, NULL);
128                         free(man_page);
129                 }
130                 exec_failed(path);
131         }
132 }
133
134 static void exec_man_konqueror(const char *path, const char *page)
135 {
136         const char *display = getenv("DISPLAY");
137
138         if (display && *display) {
139                 char *man_page;
140                 const char *filename = "kfmclient";
141
142                 /* It's simpler to launch konqueror using kfmclient. */
143                 if (path) {
144                         const char *file = strrchr(path, '/');
145                         if (file && !strcmp(file + 1, "konqueror")) {
146                                 char *new = strdup(path);
147                                 char *dest = strrchr(new, '/');
148
149                                 /* strlen("konqueror") == strlen("kfmclient") */
150                                 strcpy(dest + 1, "kfmclient");
151                                 path = new;
152                         }
153                         if (file)
154                                 filename = file;
155                 } else
156                         path = "kfmclient";
157                 if (asprintf(&man_page, "man:%s(1)", page) > 0) {
158                         execlp(path, filename, "newTab", man_page, NULL);
159                         free(man_page);
160                 }
161                 exec_failed(path);
162         }
163 }
164
165 static void exec_man_man(const char *path, const char *page)
166 {
167         if (!path)
168                 path = "man";
169         execlp(path, "man", page, NULL);
170         exec_failed(path);
171 }
172
173 static void exec_man_cmd(const char *cmd, const char *page)
174 {
175         char *shell_cmd;
176
177         if (asprintf(&shell_cmd, "%s %s", cmd, page) > 0) {
178                 execl("/bin/sh", "sh", "-c", shell_cmd, NULL);
179                 free(shell_cmd);
180         }
181         exec_failed(cmd);
182 }
183
184 static void add_man_viewer(const char *name)
185 {
186         struct man_viewer_list **p = &man_viewer_list;
187         size_t len = strlen(name);
188
189         while (*p)
190                 p = &((*p)->next);
191         *p = zalloc(sizeof(**p) + len + 1);
192         strcpy((*p)->name, name);
193 }
194
195 static int supported_man_viewer(const char *name, size_t len)
196 {
197         return (!strncasecmp("man", name, len) ||
198                 !strncasecmp("woman", name, len) ||
199                 !strncasecmp("konqueror", name, len));
200 }
201
202 static void do_add_man_viewer_info(const char *name,
203                                    size_t len,
204                                    const char *value)
205 {
206         struct man_viewer_info_list *new = zalloc(sizeof(*new) + len + 1);
207
208         strncpy(new->name, name, len);
209         new->info = strdup(value);
210         new->next = man_viewer_info_list;
211         man_viewer_info_list = new;
212 }
213
214 static void unsupported_man_viewer(const char *name, const char *var)
215 {
216         pr_warning("'%s': path for unsupported man viewer.\n"
217                    "Please consider using 'man.<tool>.%s' instead.", name, var);
218 }
219
220 static int add_man_viewer_path(const char *name,
221                                size_t len,
222                                const char *value)
223 {
224         if (supported_man_viewer(name, len))
225                 do_add_man_viewer_info(name, len, value);
226         else
227                 unsupported_man_viewer(name, "cmd");
228
229         return 0;
230 }
231
232 static int add_man_viewer_cmd(const char *name,
233                               size_t len,
234                               const char *value)
235 {
236         if (supported_man_viewer(name, len))
237                 unsupported_man_viewer(name, "path");
238         else
239                 do_add_man_viewer_info(name, len, value);
240
241         return 0;
242 }
243
244 static int add_man_viewer_info(const char *var, const char *value)
245 {
246         const char *name = var + 4;
247         const char *subkey = strrchr(name, '.');
248
249         if (!subkey) {
250                 pr_err("Config with no key for man viewer: %s", name);
251                 return -1;
252         }
253
254         if (!strcmp(subkey, ".path")) {
255                 if (!value)
256                         return config_error_nonbool(var);
257                 return add_man_viewer_path(name, subkey - name, value);
258         }
259         if (!strcmp(subkey, ".cmd")) {
260                 if (!value)
261                         return config_error_nonbool(var);
262                 return add_man_viewer_cmd(name, subkey - name, value);
263         }
264
265         pr_warning("'%s': unsupported man viewer sub key.", subkey);
266         return 0;
267 }
268
269 static int perf_help_config(const char *var, const char *value, void *cb)
270 {
271         enum help_format *help_formatp = cb;
272
273         if (!strcmp(var, "help.format")) {
274                 if (!value)
275                         return config_error_nonbool(var);
276                 *help_formatp = parse_help_format(value);
277                 if (*help_formatp == HELP_FORMAT_NONE)
278                         return -1;
279                 return 0;
280         }
281         if (!strcmp(var, "man.viewer")) {
282                 if (!value)
283                         return config_error_nonbool(var);
284                 add_man_viewer(value);
285                 return 0;
286         }
287         if (strstarts(var, "man."))
288                 return add_man_viewer_info(var, value);
289
290         return 0;
291 }
292
293 static struct cmdnames main_cmds, other_cmds;
294
295 void list_common_cmds_help(void)
296 {
297         unsigned int i, longest = 0;
298
299         for (i = 0; i < ARRAY_SIZE(common_cmds); i++) {
300                 if (longest < strlen(common_cmds[i].name))
301                         longest = strlen(common_cmds[i].name);
302         }
303
304         puts(" The most commonly used perf commands are:");
305         for (i = 0; i < ARRAY_SIZE(common_cmds); i++) {
306                 printf("   %-*s   ", longest, common_cmds[i].name);
307                 puts(common_cmds[i].help);
308         }
309 }
310
311 static const char *cmd_to_page(const char *perf_cmd)
312 {
313         char *s;
314
315         if (!perf_cmd)
316                 return "perf";
317         else if (strstarts(perf_cmd, "perf"))
318                 return perf_cmd;
319
320         return asprintf(&s, "perf-%s", perf_cmd) < 0 ? NULL : s;
321 }
322
323 static void setup_man_path(void)
324 {
325         char *new_path;
326         const char *old_path = getenv("MANPATH");
327
328         /* We should always put ':' after our path. If there is no
329          * old_path, the ':' at the end will let 'man' to try
330          * system-wide paths after ours to find the manual page. If
331          * there is old_path, we need ':' as delimiter. */
332         if (asprintf(&new_path, "%s:%s", system_path(PERF_MAN_PATH), old_path ?: "") > 0) {
333                 setenv("MANPATH", new_path, 1);
334                 free(new_path);
335         } else {
336                 pr_err("Unable to setup man path");
337         }
338 }
339
340 static void exec_viewer(const char *name, const char *page)
341 {
342         const char *info = get_man_viewer_info(name);
343
344         if (!strcasecmp(name, "man"))
345                 exec_man_man(info, page);
346         else if (!strcasecmp(name, "woman"))
347                 exec_woman_emacs(info, page);
348         else if (!strcasecmp(name, "konqueror"))
349                 exec_man_konqueror(info, page);
350         else if (info)
351                 exec_man_cmd(info, page);
352         else
353                 pr_warning("'%s': unknown man viewer.", name);
354 }
355
356 static int show_man_page(const char *perf_cmd)
357 {
358         struct man_viewer_list *viewer;
359         const char *page = cmd_to_page(perf_cmd);
360         const char *fallback = getenv("PERF_MAN_VIEWER");
361
362         setup_man_path();
363         for (viewer = man_viewer_list; viewer; viewer = viewer->next)
364                 exec_viewer(viewer->name, page); /* will return when unable */
365
366         if (fallback)
367                 exec_viewer(fallback, page);
368         exec_viewer("man", page);
369
370         pr_err("no man viewer handled the request");
371         return -1;
372 }
373
374 static int show_info_page(const char *perf_cmd)
375 {
376         const char *page = cmd_to_page(perf_cmd);
377         setenv("INFOPATH", system_path(PERF_INFO_PATH), 1);
378         execlp("info", "info", "perfman", page, NULL);
379         return -1;
380 }
381
382 static int get_html_page_path(char **page_path, const char *page)
383 {
384         struct stat st;
385         const char *html_path = system_path(PERF_HTML_PATH);
386
387         /* Check that we have a perf documentation directory. */
388         if (stat(mkpath("%s/perf.html", html_path), &st)
389             || !S_ISREG(st.st_mode)) {
390                 pr_err("'%s': not a documentation directory.", html_path);
391                 return -1;
392         }
393
394         return asprintf(page_path, "%s/%s.html", html_path, page);
395 }
396
397 /*
398  * If open_html is not defined in a platform-specific way (see for
399  * example compat/mingw.h), we use the script web--browse to display
400  * HTML.
401  */
402 #ifndef open_html
403 static void open_html(const char *path)
404 {
405         execl_cmd("web--browse", "-c", "help.browser", path, NULL);
406 }
407 #endif
408
409 static int show_html_page(const char *perf_cmd)
410 {
411         const char *page = cmd_to_page(perf_cmd);
412         char *page_path; /* it leaks but we exec bellow */
413
414         if (get_html_page_path(&page_path, page) < 0)
415                 return -1;
416
417         open_html(page_path);
418
419         return 0;
420 }
421
422 int cmd_help(int argc, const char **argv)
423 {
424         bool show_all = false;
425         enum help_format help_format = HELP_FORMAT_MAN;
426         struct option builtin_help_options[] = {
427         OPT_BOOLEAN('a', "all", &show_all, "print all available commands"),
428         OPT_SET_UINT('m', "man", &help_format, "show man page", HELP_FORMAT_MAN),
429         OPT_SET_UINT('w', "web", &help_format, "show manual in web browser",
430                         HELP_FORMAT_WEB),
431         OPT_SET_UINT('i', "info", &help_format, "show info page",
432                         HELP_FORMAT_INFO),
433         OPT_END(),
434         };
435         const char * const builtin_help_subcommands[] = {
436                 "buildid-cache", "buildid-list", "diff", "evlist", "help", "list",
437                 "record", "report", "bench", "stat", "timechart", "top", "annotate",
438                 "script", "sched", "kallsyms", "kmem", "lock", "kvm", "test", "inject", "mem", "data",
439 #ifdef HAVE_LIBELF_SUPPORT
440                 "probe",
441 #endif
442 #if defined(HAVE_LIBAUDIT_SUPPORT) || defined(HAVE_SYSCALL_TABLE_SUPPORT)
443                 "trace",
444 #endif
445         NULL };
446         const char *builtin_help_usage[] = {
447                 "perf help [--all] [--man|--web|--info] [command]",
448                 NULL
449         };
450         int rc;
451
452         load_command_list("perf-", &main_cmds, &other_cmds);
453
454         rc = perf_config(perf_help_config, &help_format);
455         if (rc)
456                 return rc;
457
458         argc = parse_options_subcommand(argc, argv, builtin_help_options,
459                         builtin_help_subcommands, builtin_help_usage, 0);
460
461         if (show_all) {
462                 printf("\n Usage: %s\n\n", perf_usage_string);
463                 list_commands("perf commands", &main_cmds, &other_cmds);
464                 printf(" %s\n\n", perf_more_info_string);
465                 return 0;
466         }
467
468         if (!argv[0]) {
469                 printf("\n usage: %s\n\n", perf_usage_string);
470                 list_common_cmds_help();
471                 printf("\n %s\n\n", perf_more_info_string);
472                 return 0;
473         }
474
475         switch (help_format) {
476         case HELP_FORMAT_MAN:
477                 rc = show_man_page(argv[0]);
478                 break;
479         case HELP_FORMAT_INFO:
480                 rc = show_info_page(argv[0]);
481                 break;
482         case HELP_FORMAT_WEB:
483                 rc = show_html_page(argv[0]);
484                 break;
485         case HELP_FORMAT_NONE:
486                 /* fall-through */
487         default:
488                 rc = -1;
489                 break;
490         }
491
492         return rc;
493 }