1/*
2 * builtin-help.c
3 *
4 * Builtin help command
5 */
6#include "perf.h"
7#include "util/cache.h"
8#include "builtin.h"
9#include "util/exec_cmd.h"
10#include "common-cmds.h"
11#include "util/parse-options.h"
12#include "util/run-command.h"
13#include "util/help.h"
14#include "util/debug.h"
15
16static struct man_viewer_list {
17	struct man_viewer_list *next;
18	char name[FLEX_ARRAY];
19} *man_viewer_list;
20
21static struct man_viewer_info_list {
22	struct man_viewer_info_list *next;
23	const char *info;
24	char name[FLEX_ARRAY];
25} *man_viewer_info_list;
26
27enum help_format {
28	HELP_FORMAT_NONE,
29	HELP_FORMAT_MAN,
30	HELP_FORMAT_INFO,
31	HELP_FORMAT_WEB,
32};
33
34static enum help_format parse_help_format(const char *format)
35{
36	if (!strcmp(format, "man"))
37		return HELP_FORMAT_MAN;
38	if (!strcmp(format, "info"))
39		return HELP_FORMAT_INFO;
40	if (!strcmp(format, "web") || !strcmp(format, "html"))
41		return HELP_FORMAT_WEB;
42
43	pr_err("unrecognized help format '%s'", format);
44	return HELP_FORMAT_NONE;
45}
46
47static const char *get_man_viewer_info(const char *name)
48{
49	struct man_viewer_info_list *viewer;
50
51	for (viewer = man_viewer_info_list; viewer; viewer = viewer->next) {
52		if (!strcasecmp(name, viewer->name))
53			return viewer->info;
54	}
55	return NULL;
56}
57
58static int check_emacsclient_version(void)
59{
60	struct strbuf buffer = STRBUF_INIT;
61	struct child_process ec_process;
62	const char *argv_ec[] = { "emacsclient", "--version", NULL };
63	int version;
64
65	/* emacsclient prints its version number on stderr */
66	memset(&ec_process, 0, sizeof(ec_process));
67	ec_process.argv = argv_ec;
68	ec_process.err = -1;
69	ec_process.stdout_to_stderr = 1;
70	if (start_command(&ec_process)) {
71		fprintf(stderr, "Failed to start emacsclient.\n");
72		return -1;
73	}
74	strbuf_read(&buffer, ec_process.err, 20);
75	close(ec_process.err);
76
77	/*
78	 * Don't bother checking return value, because "emacsclient --version"
79	 * seems to always exits with code 1.
80	 */
81	finish_command(&ec_process);
82
83	if (prefixcmp(buffer.buf, "emacsclient")) {
84		fprintf(stderr, "Failed to parse emacsclient version.\n");
85		strbuf_release(&buffer);
86		return -1;
87	}
88
89	strbuf_remove(&buffer, 0, strlen("emacsclient"));
90	version = atoi(buffer.buf);
91
92	if (version < 22) {
93		fprintf(stderr,
94			"emacsclient version '%d' too old (< 22).\n",
95			version);
96		strbuf_release(&buffer);
97		return -1;
98	}
99
100	strbuf_release(&buffer);
101	return 0;
102}
103
104static void exec_woman_emacs(const char *path, const char *page)
105{
106	char sbuf[STRERR_BUFSIZE];
107
108	if (!check_emacsclient_version()) {
109		/* This works only with emacsclient version >= 22. */
110		struct strbuf man_page = STRBUF_INIT;
111
112		if (!path)
113			path = "emacsclient";
114		strbuf_addf(&man_page, "(woman \"%s\")", page);
115		execlp(path, "emacsclient", "-e", man_page.buf, NULL);
116		warning("failed to exec '%s': %s", path,
117			strerror_r(errno, sbuf, sizeof(sbuf)));
118	}
119}
120
121static void exec_man_konqueror(const char *path, const char *page)
122{
123	const char *display = getenv("DISPLAY");
124
125	if (display && *display) {
126		struct strbuf man_page = STRBUF_INIT;
127		const char *filename = "kfmclient";
128		char sbuf[STRERR_BUFSIZE];
129
130		/* It's simpler to launch konqueror using kfmclient. */
131		if (path) {
132			const char *file = strrchr(path, '/');
133			if (file && !strcmp(file + 1, "konqueror")) {
134				char *new = strdup(path);
135				char *dest = strrchr(new, '/');
136
137				/* strlen("konqueror") == strlen("kfmclient") */
138				strcpy(dest + 1, "kfmclient");
139				path = new;
140			}
141			if (file)
142				filename = file;
143		} else
144			path = "kfmclient";
145		strbuf_addf(&man_page, "man:%s(1)", page);
146		execlp(path, filename, "newTab", man_page.buf, NULL);
147		warning("failed to exec '%s': %s", path,
148			strerror_r(errno, sbuf, sizeof(sbuf)));
149	}
150}
151
152static void exec_man_man(const char *path, const char *page)
153{
154	char sbuf[STRERR_BUFSIZE];
155
156	if (!path)
157		path = "man";
158	execlp(path, "man", page, NULL);
159	warning("failed to exec '%s': %s", path,
160		strerror_r(errno, sbuf, sizeof(sbuf)));
161}
162
163static void exec_man_cmd(const char *cmd, const char *page)
164{
165	struct strbuf shell_cmd = STRBUF_INIT;
166	char sbuf[STRERR_BUFSIZE];
167
168	strbuf_addf(&shell_cmd, "%s %s", cmd, page);
169	execl("/bin/sh", "sh", "-c", shell_cmd.buf, NULL);
170	warning("failed to exec '%s': %s", cmd,
171		strerror_r(errno, sbuf, sizeof(sbuf)));
172}
173
174static void add_man_viewer(const char *name)
175{
176	struct man_viewer_list **p = &man_viewer_list;
177	size_t len = strlen(name);
178
179	while (*p)
180		p = &((*p)->next);
181	*p = zalloc(sizeof(**p) + len + 1);
182	strncpy((*p)->name, name, len);
183}
184
185static int supported_man_viewer(const char *name, size_t len)
186{
187	return (!strncasecmp("man", name, len) ||
188		!strncasecmp("woman", name, len) ||
189		!strncasecmp("konqueror", name, len));
190}
191
192static void do_add_man_viewer_info(const char *name,
193				   size_t len,
194				   const char *value)
195{
196	struct man_viewer_info_list *new = zalloc(sizeof(*new) + len + 1);
197
198	strncpy(new->name, name, len);
199	new->info = strdup(value);
200	new->next = man_viewer_info_list;
201	man_viewer_info_list = new;
202}
203
204static int add_man_viewer_path(const char *name,
205			       size_t len,
206			       const char *value)
207{
208	if (supported_man_viewer(name, len))
209		do_add_man_viewer_info(name, len, value);
210	else
211		warning("'%s': path for unsupported man viewer.\n"
212			"Please consider using 'man.<tool>.cmd' instead.",
213			name);
214
215	return 0;
216}
217
218static int add_man_viewer_cmd(const char *name,
219			      size_t len,
220			      const char *value)
221{
222	if (supported_man_viewer(name, len))
223		warning("'%s': cmd for supported man viewer.\n"
224			"Please consider using 'man.<tool>.path' instead.",
225			name);
226	else
227		do_add_man_viewer_info(name, len, value);
228
229	return 0;
230}
231
232static int add_man_viewer_info(const char *var, const char *value)
233{
234	const char *name = var + 4;
235	const char *subkey = strrchr(name, '.');
236
237	if (!subkey)
238		return error("Config with no key for man viewer: %s", name);
239
240	if (!strcmp(subkey, ".path")) {
241		if (!value)
242			return config_error_nonbool(var);
243		return add_man_viewer_path(name, subkey - name, value);
244	}
245	if (!strcmp(subkey, ".cmd")) {
246		if (!value)
247			return config_error_nonbool(var);
248		return add_man_viewer_cmd(name, subkey - name, value);
249	}
250
251	warning("'%s': unsupported man viewer sub key.", subkey);
252	return 0;
253}
254
255static int perf_help_config(const char *var, const char *value, void *cb)
256{
257	enum help_format *help_formatp = cb;
258
259	if (!strcmp(var, "help.format")) {
260		if (!value)
261			return config_error_nonbool(var);
262		*help_formatp = parse_help_format(value);
263		if (*help_formatp == HELP_FORMAT_NONE)
264			return -1;
265		return 0;
266	}
267	if (!strcmp(var, "man.viewer")) {
268		if (!value)
269			return config_error_nonbool(var);
270		add_man_viewer(value);
271		return 0;
272	}
273	if (!prefixcmp(var, "man."))
274		return add_man_viewer_info(var, value);
275
276	return perf_default_config(var, value, cb);
277}
278
279static struct cmdnames main_cmds, other_cmds;
280
281void list_common_cmds_help(void)
282{
283	unsigned int i, longest = 0;
284
285	for (i = 0; i < ARRAY_SIZE(common_cmds); i++) {
286		if (longest < strlen(common_cmds[i].name))
287			longest = strlen(common_cmds[i].name);
288	}
289
290	puts(" The most commonly used perf commands are:");
291	for (i = 0; i < ARRAY_SIZE(common_cmds); i++) {
292		printf("   %-*s   ", longest, common_cmds[i].name);
293		puts(common_cmds[i].help);
294	}
295}
296
297static int is_perf_command(const char *s)
298{
299	return is_in_cmdlist(&main_cmds, s) ||
300		is_in_cmdlist(&other_cmds, s);
301}
302
303static const char *prepend(const char *prefix, const char *cmd)
304{
305	size_t pre_len = strlen(prefix);
306	size_t cmd_len = strlen(cmd);
307	char *p = malloc(pre_len + cmd_len + 1);
308	memcpy(p, prefix, pre_len);
309	strcpy(p + pre_len, cmd);
310	return p;
311}
312
313static const char *cmd_to_page(const char *perf_cmd)
314{
315	if (!perf_cmd)
316		return "perf";
317	else if (!prefixcmp(perf_cmd, "perf"))
318		return perf_cmd;
319	else
320		return prepend("perf-", perf_cmd);
321}
322
323static void setup_man_path(void)
324{
325	struct strbuf new_path = STRBUF_INIT;
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	strbuf_addstr(&new_path, system_path(PERF_MAN_PATH));
333	strbuf_addch(&new_path, ':');
334	if (old_path)
335		strbuf_addstr(&new_path, old_path);
336
337	setenv("MANPATH", new_path.buf, 1);
338
339	strbuf_release(&new_path);
340}
341
342static void exec_viewer(const char *name, const char *page)
343{
344	const char *info = get_man_viewer_info(name);
345
346	if (!strcasecmp(name, "man"))
347		exec_man_man(info, page);
348	else if (!strcasecmp(name, "woman"))
349		exec_woman_emacs(info, page);
350	else if (!strcasecmp(name, "konqueror"))
351		exec_man_konqueror(info, page);
352	else if (info)
353		exec_man_cmd(info, page);
354	else
355		warning("'%s': unknown man viewer.", name);
356}
357
358static int show_man_page(const char *perf_cmd)
359{
360	struct man_viewer_list *viewer;
361	const char *page = cmd_to_page(perf_cmd);
362	const char *fallback = getenv("PERF_MAN_VIEWER");
363
364	setup_man_path();
365	for (viewer = man_viewer_list; viewer; viewer = viewer->next)
366		exec_viewer(viewer->name, page); /* will return when unable */
367
368	if (fallback)
369		exec_viewer(fallback, page);
370	exec_viewer("man", page);
371
372	pr_err("no man viewer handled the request");
373	return -1;
374}
375
376static int show_info_page(const char *perf_cmd)
377{
378	const char *page = cmd_to_page(perf_cmd);
379	setenv("INFOPATH", system_path(PERF_INFO_PATH), 1);
380	execlp("info", "info", "perfman", page, NULL);
381	return -1;
382}
383
384static int get_html_page_path(struct strbuf *page_path, const char *page)
385{
386	struct stat st;
387	const char *html_path = system_path(PERF_HTML_PATH);
388
389	/* Check that we have a perf documentation directory. */
390	if (stat(mkpath("%s/perf.html", html_path), &st)
391	    || !S_ISREG(st.st_mode)) {
392		pr_err("'%s': not a documentation directory.", html_path);
393		return -1;
394	}
395
396	strbuf_init(page_path, 0);
397	strbuf_addf(page_path, "%s/%s.html", html_path, page);
398
399	return 0;
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_perf_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	struct strbuf 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.buf);
423
424	return 0;
425}
426
427int cmd_help(int argc, const char **argv, const char *prefix __maybe_unused)
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", "kmem", "lock", "kvm", "test", "inject", "mem", "data",
444#ifdef HAVE_LIBELF_SUPPORT
445		"probe",
446#endif
447#ifdef HAVE_LIBAUDIT_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	const char *alias;
456	int rc = 0;
457
458	load_command_list("perf-", &main_cmds, &other_cmds);
459
460	perf_config(perf_help_config, &help_format);
461
462	argc = parse_options_subcommand(argc, argv, builtin_help_options,
463			builtin_help_subcommands, builtin_help_usage, 0);
464
465	if (show_all) {
466		printf("\n usage: %s\n\n", perf_usage_string);
467		list_commands("perf commands", &main_cmds, &other_cmds);
468		printf(" %s\n\n", perf_more_info_string);
469		return 0;
470	}
471
472	if (!argv[0]) {
473		printf("\n usage: %s\n\n", perf_usage_string);
474		list_common_cmds_help();
475		printf("\n %s\n\n", perf_more_info_string);
476		return 0;
477	}
478
479	alias = alias_lookup(argv[0]);
480	if (alias && !is_perf_command(argv[0])) {
481		printf("`perf %s' is aliased to `%s'\n", argv[0], alias);
482		return 0;
483	}
484
485	switch (help_format) {
486	case HELP_FORMAT_MAN:
487		rc = show_man_page(argv[0]);
488		break;
489	case HELP_FORMAT_INFO:
490		rc = show_info_page(argv[0]);
491		break;
492	case HELP_FORMAT_WEB:
493		rc = show_html_page(argv[0]);
494		break;
495	case HELP_FORMAT_NONE:
496		/* fall-through */
497	default:
498		rc = -1;
499		break;
500	}
501
502	return rc;
503}
504