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
30 static struct man_viewer_list {
31 struct man_viewer_list *next;
32 char name[0];
33 } *man_viewer_list;
34
35 static 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
41 enum help_format {
42 HELP_FORMAT_NONE,
43 HELP_FORMAT_MAN,
44 HELP_FORMAT_INFO,
45 HELP_FORMAT_WEB,
46 };
47
parse_help_format(const char * format)48 static 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
get_man_viewer_info(const char * name)61 static 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(name, viewer->name))
67 return viewer->info;
68 }
69 return NULL;
70 }
71
check_emacsclient_version(void)72 static 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, ec_process.err, 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(buffer.buf, "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;
114 out:
115 strbuf_release(&buffer);
116 return ret;
117 }
118
exec_failed(const char * cmd)119 static 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
exec_woman_emacs(const char * path,const char * page)125 static 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(path);
138 }
139 }
140
exec_man_konqueror(const char * path,const char * page)141 static 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(dest + 1, "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(path);
169 }
170 }
171
exec_man_man(const char * path,const char * page)172 static 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(path);
178 }
179
exec_man_cmd(const char * cmd,const char * page)180 static 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
add_man_viewer(const char * name)191 static 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)->name, name);
200 }
201
supported_man_viewer(const char * name,size_t len)202 static int supported_man_viewer(const char *name, size_t len)
203 {
204 return (!strncasecmp("man", name, len) ||
205 !strncasecmp("woman", name, len) ||
206 !strncasecmp("konqueror", name, len));
207 }
208
do_add_man_viewer_info(const char * name,size_t len,const char * value)209 static 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(new->name, name, len);
216 new->info = strdup(value);
217 new->next = man_viewer_info_list;
218 man_viewer_info_list = new;
219 }
220
unsupported_man_viewer(const char * name,const char * var)221 static 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
add_man_viewer_path(const char * name,size_t len,const char * value)227 static 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, "cmd");
235
236 return 0;
237 }
238
add_man_viewer_cmd(const char * name,size_t len,const char * value)239 static 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, "path");
245 else
246 do_add_man_viewer_info(name, len, value);
247
248 return 0;
249 }
250
add_man_viewer_info(const char * var,const char * value)251 static 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, 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, subkey - name, value);
270 }
271
272 pr_warning("'%s': unsupported man viewer sub key.", subkey);
273 return 0;
274 }
275
perf_help_config(const char * var,const char * value,void * cb)276 static 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(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(value);
292 return 0;
293 }
294 if (strstarts(var, "man."))
295 return add_man_viewer_info(var, value);
296
297 return 0;
298 }
299
300 static struct cmdnames main_cmds, other_cmds;
301
list_common_cmds_help(void)302 void 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
cmd_to_page(const char * perf_cmd)318 static 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(perf_cmd, "perf"))
325 return perf_cmd;
326
327 return asprintf(&s, "perf-%s", perf_cmd) < 0 ? NULL : s;
328 }
329
setup_man_path(void)330 static 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
exec_viewer(const char * name,const char * page)347 static void exec_viewer(const char *name, const char *page)
348 {
349 const char *info = get_man_viewer_info(name);
350
351 if (!strcasecmp(name, "man"))
352 exec_man_man(info, page);
353 else if (!strcasecmp(name, "woman"))
354 exec_woman_emacs(info, page);
355 else if (!strcasecmp(name, "konqueror"))
356 exec_man_konqueror(info, page);
357 else if (info)
358 exec_man_cmd(info, page);
359 else
360 pr_warning("'%s': unknown man viewer.", name);
361 }
362
show_man_page(const char * perf_cmd)363 static 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(viewer->name, page); /* will return when unable */
372
373 if (fallback)
374 exec_viewer(fallback, page);
375 exec_viewer("man", page);
376
377 pr_err("no man viewer handled the request");
378 return -1;
379 }
380
show_info_page(const char * perf_cmd)381 static 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
get_html_page_path(char ** page_path,const char * page)389 static 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, sizeof(path), "%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
open_html(const char * path)411 static void open_html(const char *path)
412 {
413 execl_cmd("web--browse", "-c", "help.browser", path, NULL);
414 }
415 #endif
416
show_html_page(const char * perf_cmd)417 static 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) < 0)
423 return -1;
424
425 open_html(page_path);
426
427 return 0;
428 }
429
cmd_help(int argc,const char ** argv)430 int 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 #if defined(HAVE_LIBAUDIT_SUPPORT) || defined(HAVE_SYSCALL_TABLE_SUPPORT)
451 "trace",
452 #endif
453 NULL };
454 const char *builtin_help_usage[] = {
455 "perf help [--all] [--man|--web|--info] [command]",
456 NULL
457 };
458 int rc;
459
460 load_command_list("perf-", &main_cmds, &other_cmds);
461
462 rc = perf_config(perf_help_config, &help_format);
463 if (rc)
464 return rc;
465
466 argc = parse_options_subcommand(argc, argv, builtin_help_options,
467 builtin_help_subcommands, builtin_help_usage, 0);
468
469 if (show_all) {
470 printf("\n Usage: %s\n\n", perf_usage_string);
471 list_commands("perf commands", &main_cmds, &other_cmds);
472 printf(" %s\n\n", perf_more_info_string);
473 return 0;
474 }
475
476 if (!argv[0]) {
477 printf("\n usage: %s\n\n", perf_usage_string);
478 list_common_cmds_help();
479 printf("\n %s\n\n", perf_more_info_string);
480 return 0;
481 }
482
483 switch (help_format) {
484 case HELP_FORMAT_MAN:
485 rc = show_man_page(argv[0]);
486 break;
487 case HELP_FORMAT_INFO:
488 rc = show_info_page(argv[0]);
489 break;
490 case HELP_FORMAT_WEB:
491 rc = show_html_page(argv[0]);
492 break;
493 case HELP_FORMAT_NONE:
494 /* fall-through */
495 default:
496 rc = -1;
497 break;
498 }
499
500 return rc;
501 }
502