GNU Linux-libre 5.10.219-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 "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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
408 static void open_html(const char *path)
409 {
410         execl_cmd("web--browse", "-c", "help.browser", path, NULL);
411 }
412 #endif
413
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
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 }