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v5.4
  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
 28static struct man_viewer_list {
 29	struct man_viewer_list *next;
 30	char name[0];
 31} *man_viewer_list;
 32
 33static 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
 39enum help_format {
 40	HELP_FORMAT_NONE,
 41	HELP_FORMAT_MAN,
 42	HELP_FORMAT_INFO,
 43	HELP_FORMAT_WEB,
 44};
 45
 46static 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
 59static 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
 70static 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;
112out:
113	strbuf_release(&buffer);
114	return ret;
115}
116
117static 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
123static 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
139static 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
170static 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
178static 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
189static 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
200static 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
207static 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
219static 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
225static 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
237static 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
249static 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
274static 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
298static struct cmdnames main_cmds, other_cmds;
299
300void 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
316static 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
328static 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
345static 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
361static 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
379static 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
387static 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
408static void open_html(const char *path)
409{
410	execl_cmd("web--browse", "-c", "help.browser", path, NULL);
411}
412#endif
413
414static 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
427int 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}
v6.8
  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(name, 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, 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;
114out:
115	strbuf_release(&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(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(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
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(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)->name, name);
200}
201
202static 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
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(new->name, name, 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, "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, "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, 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
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(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
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(perf_cmd, "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(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
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(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
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, 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
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 bellow */
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
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#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}