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