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 strncpy((*p)->name, name, len);
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 }
494
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