1// SPDX-License-Identifier: GPL-2.0
2/*
3 * builtin-help.c
4 *
5 * Builtin help command
6 */
7#include "util/cache.h"
8#include "util/config.h"
9#include "util/strbuf.h"
10#include "builtin.h"
11#include <subcmd/exec-cmd.h>
12#include "common-cmds.h"
13#include <subcmd/parse-options.h>
14#include <subcmd/run-command.h>
15#include <subcmd/help.h>
16#include "util/debug.h"
17#include "util/util.h"
18#include <linux/kernel.h>
19#include <linux/string.h>
20#include <linux/zalloc.h>
21#include <errno.h>
22#include <limits.h>
23#include <stdio.h>
24#include <stdlib.h>
25#include <string.h>
26#include <sys/types.h>
27#include <sys/stat.h>
28#include <unistd.h>
29
30static struct man_viewer_list {
31 struct man_viewer_list *next;
32 char name[0];
33} *man_viewer_list;
34
35static struct man_viewer_info_list {
36 struct man_viewer_info_list *next;
37 const char *info;
38 char name[0];
39} *man_viewer_info_list;
40
41enum help_format {
42 HELP_FORMAT_NONE,
43 HELP_FORMAT_MAN,
44 HELP_FORMAT_INFO,
45 HELP_FORMAT_WEB,
46};
47
48static enum help_format parse_help_format(const char *format)
49{
50 if (!strcmp(format, "man"))
51 return HELP_FORMAT_MAN;
52 if (!strcmp(format, "info"))
53 return HELP_FORMAT_INFO;
54 if (!strcmp(format, "web") || !strcmp(format, "html"))
55 return HELP_FORMAT_WEB;
56
57 pr_err("unrecognized help format '%s'", format);
58 return HELP_FORMAT_NONE;
59}
60
61static const char *get_man_viewer_info(const char *name)
62{
63 struct man_viewer_info_list *viewer;
64
65 for (viewer = man_viewer_info_list; viewer; viewer = viewer->next) {
66 if (!strcasecmp(s1: name, s2: viewer->name))
67 return viewer->info;
68 }
69 return NULL;
70}
71
72static int check_emacsclient_version(void)
73{
74 struct strbuf buffer = STRBUF_INIT;
75 struct child_process ec_process;
76 const char *argv_ec[] = { "emacsclient", "--version", NULL };
77 int version;
78 int ret = -1;
79
80 /* emacsclient prints its version number on stderr */
81 memset(&ec_process, 0, sizeof(ec_process));
82 ec_process.argv = argv_ec;
83 ec_process.err = -1;
84 ec_process.stdout_to_stderr = 1;
85 if (start_command(&ec_process)) {
86 fprintf(stderr, "Failed to start emacsclient.\n");
87 return -1;
88 }
89 if (strbuf_read(&buffer, fd: ec_process.err, hint: 20) < 0) {
90 fprintf(stderr, "Failed to read emacsclient version\n");
91 goto out;
92 }
93 close(ec_process.err);
94
95 /*
96 * Don't bother checking return value, because "emacsclient --version"
97 * seems to always exits with code 1.
98 */
99 finish_command(&ec_process);
100
101 if (!strstarts(str: buffer.buf, prefix: "emacsclient")) {
102 fprintf(stderr, "Failed to parse emacsclient version.\n");
103 goto out;
104 }
105
106 version = atoi(buffer.buf + strlen("emacsclient"));
107
108 if (version < 22) {
109 fprintf(stderr,
110 "emacsclient version '%d' too old (< 22).\n",
111 version);
112 } else
113 ret = 0;
114out:
115 strbuf_release(buf: &buffer);
116 return ret;
117}
118
119static void exec_failed(const char *cmd)
120{
121 char sbuf[STRERR_BUFSIZE];
122 pr_warning("failed to exec '%s': %s", cmd, str_error_r(errno, sbuf, sizeof(sbuf)));
123}
124
125static void exec_woman_emacs(const char *path, const char *page)
126{
127 if (!check_emacsclient_version()) {
128 /* This works only with emacsclient version >= 22. */
129 char *man_page;
130
131 if (!path)
132 path = "emacsclient";
133 if (asprintf(&man_page, "(woman \"%s\")", page) > 0) {
134 execlp(path, "emacsclient", "-e", man_page, NULL);
135 free(man_page);
136 }
137 exec_failed(cmd: path);
138 }
139}
140
141static void exec_man_konqueror(const char *path, const char *page)
142{
143 const char *display = getenv("DISPLAY");
144
145 if (display && *display) {
146 char *man_page;
147 const char *filename = "kfmclient";
148
149 /* It's simpler to launch konqueror using kfmclient. */
150 if (path) {
151 const char *file = strrchr(path, '/');
152 if (file && !strcmp(file + 1, "konqueror")) {
153 char *new = strdup(path);
154 char *dest = strrchr(new, '/');
155
156 /* strlen("konqueror") == strlen("kfmclient") */
157 strcpy(p: dest + 1, q: "kfmclient");
158 path = new;
159 }
160 if (file)
161 filename = file;
162 } else
163 path = "kfmclient";
164 if (asprintf(&man_page, "man:%s(1)", page) > 0) {
165 execlp(path, filename, "newTab", man_page, NULL);
166 free(man_page);
167 }
168 exec_failed(cmd: path);
169 }
170}
171
172static void exec_man_man(const char *path, const char *page)
173{
174 if (!path)
175 path = "man";
176 execlp(path, "man", page, NULL);
177 exec_failed(cmd: path);
178}
179
180static void exec_man_cmd(const char *cmd, const char *page)
181{
182 char *shell_cmd;
183
184 if (asprintf(&shell_cmd, "%s %s", cmd, page) > 0) {
185 execl("/bin/sh", "sh", "-c", shell_cmd, NULL);
186 free(shell_cmd);
187 }
188 exec_failed(cmd);
189}
190
191static void add_man_viewer(const char *name)
192{
193 struct man_viewer_list **p = &man_viewer_list;
194 size_t len = strlen(name);
195
196 while (*p)
197 p = &((*p)->next);
198 *p = zalloc(sizeof(**p) + len + 1);
199 strcpy(p: (*p)->name, q: name);
200}
201
202static int supported_man_viewer(const char *name, size_t len)
203{
204 return (!strncasecmp(s1: "man", s2: name, n: len) ||
205 !strncasecmp(s1: "woman", s2: name, n: len) ||
206 !strncasecmp(s1: "konqueror", s2: name, n: len));
207}
208
209static void do_add_man_viewer_info(const char *name,
210 size_t len,
211 const char *value)
212{
213 struct man_viewer_info_list *new = zalloc(sizeof(*new) + len + 1);
214
215 strncpy(p: new->name, q: name, size: len);
216 new->info = strdup(value);
217 new->next = man_viewer_info_list;
218 man_viewer_info_list = new;
219}
220
221static void unsupported_man_viewer(const char *name, const char *var)
222{
223 pr_warning("'%s': path for unsupported man viewer.\n"
224 "Please consider using 'man.<tool>.%s' instead.", name, var);
225}
226
227static int add_man_viewer_path(const char *name,
228 size_t len,
229 const char *value)
230{
231 if (supported_man_viewer(name, len))
232 do_add_man_viewer_info(name, len, value);
233 else
234 unsupported_man_viewer(name, var: "cmd");
235
236 return 0;
237}
238
239static int add_man_viewer_cmd(const char *name,
240 size_t len,
241 const char *value)
242{
243 if (supported_man_viewer(name, len))
244 unsupported_man_viewer(name, var: "path");
245 else
246 do_add_man_viewer_info(name, len, value);
247
248 return 0;
249}
250
251static int add_man_viewer_info(const char *var, const char *value)
252{
253 const char *name = var + 4;
254 const char *subkey = strrchr(name, '.');
255
256 if (!subkey) {
257 pr_err("Config with no key for man viewer: %s", name);
258 return -1;
259 }
260
261 if (!strcmp(subkey, ".path")) {
262 if (!value)
263 return config_error_nonbool(var);
264 return add_man_viewer_path(name, len: subkey - name, value);
265 }
266 if (!strcmp(subkey, ".cmd")) {
267 if (!value)
268 return config_error_nonbool(var);
269 return add_man_viewer_cmd(name, len: subkey - name, value);
270 }
271
272 pr_warning("'%s': unsupported man viewer sub key.", subkey);
273 return 0;
274}
275
276static int perf_help_config(const char *var, const char *value, void *cb)
277{
278 enum help_format *help_formatp = cb;
279
280 if (!strcmp(var, "help.format")) {
281 if (!value)
282 return config_error_nonbool(var);
283 *help_formatp = parse_help_format(format: value);
284 if (*help_formatp == HELP_FORMAT_NONE)
285 return -1;
286 return 0;
287 }
288 if (!strcmp(var, "man.viewer")) {
289 if (!value)
290 return config_error_nonbool(var);
291 add_man_viewer(name: value);
292 return 0;
293 }
294 if (strstarts(str: var, prefix: "man."))
295 return add_man_viewer_info(var, value);
296
297 return 0;
298}
299
300static struct cmdnames main_cmds, other_cmds;
301
302void list_common_cmds_help(void)
303{
304 unsigned int i, longest = 0;
305
306 for (i = 0; i < ARRAY_SIZE(common_cmds); i++) {
307 if (longest < strlen(common_cmds[i].name))
308 longest = strlen(common_cmds[i].name);
309 }
310
311 puts(" The most commonly used perf commands are:");
312 for (i = 0; i < ARRAY_SIZE(common_cmds); i++) {
313 printf(" %-*s ", longest, common_cmds[i].name);
314 puts(common_cmds[i].help);
315 }
316}
317
318static const char *cmd_to_page(const char *perf_cmd)
319{
320 char *s;
321
322 if (!perf_cmd)
323 return "perf";
324 else if (strstarts(str: perf_cmd, prefix: "perf"))
325 return perf_cmd;
326
327 return asprintf(&s, "perf-%s", perf_cmd) < 0 ? NULL : s;
328}
329
330static void setup_man_path(void)
331{
332 char *new_path;
333 const char *old_path = getenv("MANPATH");
334
335 /* We should always put ':' after our path. If there is no
336 * old_path, the ':' at the end will let 'man' to try
337 * system-wide paths after ours to find the manual page. If
338 * there is old_path, we need ':' as delimiter. */
339 if (asprintf(&new_path, "%s:%s", system_path(PERF_MAN_PATH), old_path ?: "") > 0) {
340 setenv("MANPATH", new_path, 1);
341 free(new_path);
342 } else {
343 pr_err("Unable to setup man path");
344 }
345}
346
347static void exec_viewer(const char *name, const char *page)
348{
349 const char *info = get_man_viewer_info(name);
350
351 if (!strcasecmp(s1: name, s2: "man"))
352 exec_man_man(path: info, page);
353 else if (!strcasecmp(s1: name, s2: "woman"))
354 exec_woman_emacs(path: info, page);
355 else if (!strcasecmp(s1: name, s2: "konqueror"))
356 exec_man_konqueror(path: info, page);
357 else if (info)
358 exec_man_cmd(cmd: info, page);
359 else
360 pr_warning("'%s': unknown man viewer.", name);
361}
362
363static int show_man_page(const char *perf_cmd)
364{
365 struct man_viewer_list *viewer;
366 const char *page = cmd_to_page(perf_cmd);
367 const char *fallback = getenv("PERF_MAN_VIEWER");
368
369 setup_man_path();
370 for (viewer = man_viewer_list; viewer; viewer = viewer->next)
371 exec_viewer(name: viewer->name, page); /* will return when unable */
372
373 if (fallback)
374 exec_viewer(name: fallback, page);
375 exec_viewer(name: "man", page);
376
377 pr_err("no man viewer handled the request");
378 return -1;
379}
380
381static int show_info_page(const char *perf_cmd)
382{
383 const char *page = cmd_to_page(perf_cmd);
384 setenv("INFOPATH", system_path(PERF_INFO_PATH), 1);
385 execlp("info", "info", "perfman", page, NULL);
386 return -1;
387}
388
389static int get_html_page_path(char **page_path, const char *page)
390{
391 struct stat st;
392 const char *html_path = system_path(PERF_HTML_PATH);
393 char path[PATH_MAX];
394
395 /* Check that we have a perf documentation directory. */
396 if (stat(mkpath(path_buf: path, sz: sizeof(path), fmt: "%s/perf.html", html_path), &st)
397 || !S_ISREG(st.st_mode)) {
398 pr_err("'%s': not a documentation directory.", html_path);
399 return -1;
400 }
401
402 return asprintf(page_path, "%s/%s.html", html_path, page);
403}
404
405/*
406 * If open_html is not defined in a platform-specific way (see for
407 * example compat/mingw.h), we use the script web--browse to display
408 * HTML.
409 */
410#ifndef open_html
411static void open_html(const char *path)
412{
413 execl_cmd("web--browse", "-c", "help.browser", path, NULL);
414}
415#endif
416
417static int show_html_page(const char *perf_cmd)
418{
419 const char *page = cmd_to_page(perf_cmd);
420 char *page_path; /* it leaks but we exec below */
421
422 if (get_html_page_path(page_path: &page_path, page) < 0)
423 return -1;
424
425 open_html(path: page_path);
426
427 return 0;
428}
429
430int cmd_help(int argc, const char **argv)
431{
432 bool show_all = false;
433 enum help_format help_format = HELP_FORMAT_MAN;
434 struct option builtin_help_options[] = {
435 OPT_BOOLEAN('a', "all", &show_all, "print all available commands"),
436 OPT_SET_UINT('m', "man", &help_format, "show man page", HELP_FORMAT_MAN),
437 OPT_SET_UINT('w', "web", &help_format, "show manual in web browser",
438 HELP_FORMAT_WEB),
439 OPT_SET_UINT('i', "info", &help_format, "show info page",
440 HELP_FORMAT_INFO),
441 OPT_END(),
442 };
443 const char * const builtin_help_subcommands[] = {
444 "buildid-cache", "buildid-list", "diff", "evlist", "help", "list",
445 "record", "report", "bench", "stat", "timechart", "top", "annotate",
446 "script", "sched", "kallsyms", "kmem", "lock", "kvm", "test", "inject", "mem", "data",
447#ifdef HAVE_LIBELF_SUPPORT
448 "probe",
449#endif
450 "trace",
451 NULL };
452 const char *builtin_help_usage[] = {
453 "perf help [--all] [--man|--web|--info] [command]",
454 NULL
455 };
456 int rc;
457
458 load_command_list("perf-", &main_cmds, &other_cmds);
459
460 rc = perf_config(fn: perf_help_config, &help_format);
461 if (rc)
462 return rc;
463
464 argc = parse_options_subcommand(argc, argv, builtin_help_options,
465 builtin_help_subcommands, builtin_help_usage, 0);
466
467 if (show_all) {
468 printf("\n Usage: %s\n\n", perf_usage_string);
469 list_commands("perf commands", &main_cmds, &other_cmds);
470 printf(" %s\n\n", perf_more_info_string);
471 return 0;
472 }
473
474 if (!argv[0]) {
475 printf("\n usage: %s\n\n", perf_usage_string);
476 list_common_cmds_help();
477 printf("\n %s\n\n", perf_more_info_string);
478 return 0;
479 }
480
481 switch (help_format) {
482 case HELP_FORMAT_MAN:
483 rc = show_man_page(perf_cmd: argv[0]);
484 break;
485 case HELP_FORMAT_INFO:
486 rc = show_info_page(perf_cmd: argv[0]);
487 break;
488 case HELP_FORMAT_WEB:
489 rc = show_html_page(perf_cmd: argv[0]);
490 break;
491 case HELP_FORMAT_NONE:
492 /* fall-through */
493 default:
494 rc = -1;
495 break;
496 }
497
498 return rc;
499}
500

source code of linux/tools/perf/builtin-help.c