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
15static struct man_viewer_list {
16	struct man_viewer_list *next;
17	char name[FLEX_ARRAY];
18} *man_viewer_list;
19
20static struct man_viewer_info_list {
21	struct man_viewer_info_list *next;
22	const char *info;
23	char name[FLEX_ARRAY];
24} *man_viewer_info_list;
25
26enum help_format {
27	HELP_FORMAT_NONE,
28	HELP_FORMAT_MAN,
29	HELP_FORMAT_INFO,
30	HELP_FORMAT_WEB,
31};
32
33static enum help_format parse_help_format(const char *format)
34{
35	if (!strcmp(format, "man"))
36		return HELP_FORMAT_MAN;
37	if (!strcmp(format, "info"))
38		return HELP_FORMAT_INFO;
39	if (!strcmp(format, "web") || !strcmp(format, "html"))
40		return HELP_FORMAT_WEB;
41
42	pr_err("unrecognized help format '%s'", format);
43	return HELP_FORMAT_NONE;
44}
45
46static const char *get_man_viewer_info(const char *name)
47{
48	struct man_viewer_info_list *viewer;
49
50	for (viewer = man_viewer_info_list; viewer; viewer = viewer->next) {
51		if (!strcasecmp(name, viewer->name))
52			return viewer->info;
53	}
54	return NULL;
55}
56
57static int check_emacsclient_version(void)
58{
59	struct strbuf buffer = STRBUF_INIT;
60	struct child_process ec_process;
61	const char *argv_ec[] = { "emacsclient", "--version", NULL };
62	int version;
63
64	/* emacsclient prints its version number on stderr */
65	memset(&ec_process, 0, sizeof(ec_process));
66	ec_process.argv = argv_ec;
67	ec_process.err = -1;
68	ec_process.stdout_to_stderr = 1;
69	if (start_command(&ec_process)) {
70		fprintf(stderr, "Failed to start emacsclient.\n");
71		return -1;
72	}
73	strbuf_read(&buffer, ec_process.err, 20);
74	close(ec_process.err);
75
76	/*
77	 * Don't bother checking return value, because "emacsclient --version"
78	 * seems to always exits with code 1.
79	 */
80	finish_command(&ec_process);
81
82	if (prefixcmp(buffer.buf, "emacsclient")) {
83		fprintf(stderr, "Failed to parse emacsclient version.\n");
84		strbuf_release(&buffer);
85		return -1;
86	}
87
88	strbuf_remove(&buffer, 0, strlen("emacsclient"));
89	version = atoi(buffer.buf);
90
91	if (version < 22) {
92		fprintf(stderr,
93			"emacsclient version '%d' too old (< 22).\n",
94			version);
95		strbuf_release(&buffer);
96		return -1;
97	}
98
99	strbuf_release(&buffer);
100	return 0;
101}
102
103static void exec_woman_emacs(const char *path, const char *page)
104{
105	if (!check_emacsclient_version()) {
106		/* This works only with emacsclient version >= 22. */
107		struct strbuf man_page = STRBUF_INIT;
108
109		if (!path)
110			path = "emacsclient";
111		strbuf_addf(&man_page, "(woman \"%s\")", page);
112		execlp(path, "emacsclient", "-e", man_page.buf, NULL);
113		warning("failed to exec '%s': %s", path, strerror(errno));
114	}
115}
116
117static void exec_man_konqueror(const char *path, const char *page)
118{
119	const char *display = getenv("DISPLAY");
120	if (display && *display) {
121		struct strbuf man_page = STRBUF_INIT;
122		const char *filename = "kfmclient";
123
124		/* It's simpler to launch konqueror using kfmclient. */
125		if (path) {
126			const char *file = strrchr(path, '/');
127			if (file && !strcmp(file + 1, "konqueror")) {
128				char *new = strdup(path);
129				char *dest = strrchr(new, '/');
130
131				/* strlen("konqueror") == strlen("kfmclient") */
132				strcpy(dest + 1, "kfmclient");
133				path = new;
134			}
135			if (file)
136				filename = file;
137		} else
138			path = "kfmclient";
139		strbuf_addf(&man_page, "man:%s(1)", page);
140		execlp(path, filename, "newTab", man_page.buf, NULL);
141		warning("failed to exec '%s': %s", path, strerror(errno));
142	}
143}
144
145static void exec_man_man(const char *path, const char *page)
146{
147	if (!path)
148		path = "man";
149	execlp(path, "man", page, NULL);
150	warning("failed to exec '%s': %s", path, strerror(errno));
151}
152
153static void exec_man_cmd(const char *cmd, const char *page)
154{
155	struct strbuf shell_cmd = STRBUF_INIT;
156	strbuf_addf(&shell_cmd, "%s %s", cmd, page);
157	execl("/bin/sh", "sh", "-c", shell_cmd.buf, NULL);
158	warning("failed to exec '%s': %s", cmd, strerror(errno));
159}
160
161static void add_man_viewer(const char *name)
162{
163	struct man_viewer_list **p = &man_viewer_list;
164	size_t len = strlen(name);
165
166	while (*p)
167		p = &((*p)->next);
168	*p = zalloc(sizeof(**p) + len + 1);
169	strncpy((*p)->name, name, len);
170}
171
172static int supported_man_viewer(const char *name, size_t len)
173{
174	return (!strncasecmp("man", name, len) ||
175		!strncasecmp("woman", name, len) ||
176		!strncasecmp("konqueror", name, len));
177}
178
179static void do_add_man_viewer_info(const char *name,
180				   size_t len,
181				   const char *value)
182{
183	struct man_viewer_info_list *new = zalloc(sizeof(*new) + len + 1);
184
185	strncpy(new->name, name, len);
186	new->info = strdup(value);
187	new->next = man_viewer_info_list;
188	man_viewer_info_list = new;
189}
190
191static int add_man_viewer_path(const char *name,
192			       size_t len,
193			       const char *value)
194{
195	if (supported_man_viewer(name, len))
196		do_add_man_viewer_info(name, len, value);
197	else
198		warning("'%s': path for unsupported man viewer.\n"
199			"Please consider using 'man.<tool>.cmd' instead.",
200			name);
201
202	return 0;
203}
204
205static int add_man_viewer_cmd(const char *name,
206			      size_t len,
207			      const char *value)
208{
209	if (supported_man_viewer(name, len))
210		warning("'%s': cmd for supported man viewer.\n"
211			"Please consider using 'man.<tool>.path' instead.",
212			name);
213	else
214		do_add_man_viewer_info(name, len, value);
215
216	return 0;
217}
218
219static int add_man_viewer_info(const char *var, const char *value)
220{
221	const char *name = var + 4;
222	const char *subkey = strrchr(name, '.');
223
224	if (!subkey)
225		return error("Config with no key for man viewer: %s", name);
226
227	if (!strcmp(subkey, ".path")) {
228		if (!value)
229			return config_error_nonbool(var);
230		return add_man_viewer_path(name, subkey - name, value);
231	}
232	if (!strcmp(subkey, ".cmd")) {
233		if (!value)
234			return config_error_nonbool(var);
235		return add_man_viewer_cmd(name, subkey - name, value);
236	}
237
238	warning("'%s': unsupported man viewer sub key.", subkey);
239	return 0;
240}
241
242static int perf_help_config(const char *var, const char *value, void *cb)
243{
244	enum help_format *help_formatp = cb;
245
246	if (!strcmp(var, "help.format")) {
247		if (!value)
248			return config_error_nonbool(var);
249		*help_formatp = parse_help_format(value);
250		if (*help_formatp == HELP_FORMAT_NONE)
251			return -1;
252		return 0;
253	}
254	if (!strcmp(var, "man.viewer")) {
255		if (!value)
256			return config_error_nonbool(var);
257		add_man_viewer(value);
258		return 0;
259	}
260	if (!prefixcmp(var, "man."))
261		return add_man_viewer_info(var, value);
262
263	return perf_default_config(var, value, cb);
264}
265
266static struct cmdnames main_cmds, other_cmds;
267
268void list_common_cmds_help(void)
269{
270	unsigned int i, longest = 0;
271
272	for (i = 0; i < ARRAY_SIZE(common_cmds); i++) {
273		if (longest < strlen(common_cmds[i].name))
274			longest = strlen(common_cmds[i].name);
275	}
276
277	puts(" The most commonly used perf commands are:");
278	for (i = 0; i < ARRAY_SIZE(common_cmds); i++) {
279		printf("   %-*s   ", longest, common_cmds[i].name);
280		puts(common_cmds[i].help);
281	}
282}
283
284static int is_perf_command(const char *s)
285{
286	return is_in_cmdlist(&main_cmds, s) ||
287		is_in_cmdlist(&other_cmds, s);
288}
289
290static const char *prepend(const char *prefix, const char *cmd)
291{
292	size_t pre_len = strlen(prefix);
293	size_t cmd_len = strlen(cmd);
294	char *p = malloc(pre_len + cmd_len + 1);
295	memcpy(p, prefix, pre_len);
296	strcpy(p + pre_len, cmd);
297	return p;
298}
299
300static const char *cmd_to_page(const char *perf_cmd)
301{
302	if (!perf_cmd)
303		return "perf";
304	else if (!prefixcmp(perf_cmd, "perf"))
305		return perf_cmd;
306	else
307		return prepend("perf-", perf_cmd);
308}
309
310static void setup_man_path(void)
311{
312	struct strbuf new_path = STRBUF_INIT;
313	const char *old_path = getenv("MANPATH");
314
315	/* We should always put ':' after our path. If there is no
316	 * old_path, the ':' at the end will let 'man' to try
317	 * system-wide paths after ours to find the manual page. If
318	 * there is old_path, we need ':' as delimiter. */
319	strbuf_addstr(&new_path, system_path(PERF_MAN_PATH));
320	strbuf_addch(&new_path, ':');
321	if (old_path)
322		strbuf_addstr(&new_path, old_path);
323
324	setenv("MANPATH", new_path.buf, 1);
325
326	strbuf_release(&new_path);
327}
328
329static void exec_viewer(const char *name, const char *page)
330{
331	const char *info = get_man_viewer_info(name);
332
333	if (!strcasecmp(name, "man"))
334		exec_man_man(info, page);
335	else if (!strcasecmp(name, "woman"))
336		exec_woman_emacs(info, page);
337	else if (!strcasecmp(name, "konqueror"))
338		exec_man_konqueror(info, page);
339	else if (info)
340		exec_man_cmd(info, page);
341	else
342		warning("'%s': unknown man viewer.", name);
343}
344
345static int show_man_page(const char *perf_cmd)
346{
347	struct man_viewer_list *viewer;
348	const char *page = cmd_to_page(perf_cmd);
349	const char *fallback = getenv("PERF_MAN_VIEWER");
350
351	setup_man_path();
352	for (viewer = man_viewer_list; viewer; viewer = viewer->next)
353		exec_viewer(viewer->name, page); /* will return when unable */
354
355	if (fallback)
356		exec_viewer(fallback, page);
357	exec_viewer("man", page);
358
359	pr_err("no man viewer handled the request");
360	return -1;
361}
362
363static int show_info_page(const char *perf_cmd)
364{
365	const char *page = cmd_to_page(perf_cmd);
366	setenv("INFOPATH", system_path(PERF_INFO_PATH), 1);
367	execlp("info", "info", "perfman", page, NULL);
368	return -1;
369}
370
371static int get_html_page_path(struct strbuf *page_path, const char *page)
372{
373	struct stat st;
374	const char *html_path = system_path(PERF_HTML_PATH);
375
376	/* Check that we have a perf documentation directory. */
377	if (stat(mkpath("%s/perf.html", html_path), &st)
378	    || !S_ISREG(st.st_mode)) {
379		pr_err("'%s': not a documentation directory.", html_path);
380		return -1;
381	}
382
383	strbuf_init(page_path, 0);
384	strbuf_addf(page_path, "%s/%s.html", html_path, page);
385
386	return 0;
387}
388
389/*
390 * If open_html is not defined in a platform-specific way (see for
391 * example compat/mingw.h), we use the script web--browse to display
392 * HTML.
393 */
394#ifndef open_html
395static void open_html(const char *path)
396{
397	execl_perf_cmd("web--browse", "-c", "help.browser", path, NULL);
398}
399#endif
400
401static int show_html_page(const char *perf_cmd)
402{
403	const char *page = cmd_to_page(perf_cmd);
404	struct strbuf page_path; /* it leaks but we exec bellow */
405
406	if (get_html_page_path(&page_path, page) != 0)
407		return -1;
408
409	open_html(page_path.buf);
410
411	return 0;
412}
413
414int cmd_help(int argc, const char **argv, const char *prefix __maybe_unused)
415{
416	bool show_all = false;
417	enum help_format help_format = HELP_FORMAT_MAN;
418	struct option builtin_help_options[] = {
419	OPT_BOOLEAN('a', "all", &show_all, "print all available commands"),
420	OPT_SET_UINT('m', "man", &help_format, "show man page", HELP_FORMAT_MAN),
421	OPT_SET_UINT('w', "web", &help_format, "show manual in web browser",
422			HELP_FORMAT_WEB),
423	OPT_SET_UINT('i', "info", &help_format, "show info page",
424			HELP_FORMAT_INFO),
425	OPT_END(),
426	};
427	const char * const builtin_help_usage[] = {
428		"perf help [--all] [--man|--web|--info] [command]",
429		NULL
430	};
431	const char *alias;
432	int rc = 0;
433
434	load_command_list("perf-", &main_cmds, &other_cmds);
435
436	perf_config(perf_help_config, &help_format);
437
438	argc = parse_options(argc, argv, builtin_help_options,
439			builtin_help_usage, 0);
440
441	if (show_all) {
442		printf("\n usage: %s\n\n", perf_usage_string);
443		list_commands("perf commands", &main_cmds, &other_cmds);
444		printf(" %s\n\n", perf_more_info_string);
445		return 0;
446	}
447
448	if (!argv[0]) {
449		printf("\n usage: %s\n\n", perf_usage_string);
450		list_common_cmds_help();
451		printf("\n %s\n\n", perf_more_info_string);
452		return 0;
453	}
454
455	alias = alias_lookup(argv[0]);
456	if (alias && !is_perf_command(argv[0])) {
457		printf("`perf %s' is aliased to `%s'\n", argv[0], alias);
458		return 0;
459	}
460
461	switch (help_format) {
462	case HELP_FORMAT_MAN:
463		rc = show_man_page(argv[0]);
464		break;
465	case HELP_FORMAT_INFO:
466		rc = show_info_page(argv[0]);
467		break;
468	case HELP_FORMAT_WEB:
469		rc = show_html_page(argv[0]);
470		break;
471	case HELP_FORMAT_NONE:
472		/* fall-through */
473	default:
474		rc = -1;
475		break;
476	}
477
478	return rc;
479}
480