Linux Perf
builtin-help.c
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1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * builtin-help.c
4  *
5  * Builtin help command
6  */
7 #include "perf.h"
8 #include "util/config.h"
9 #include "builtin.h"
10 #include <subcmd/exec-cmd.h>
11 #include "common-cmds.h"
12 #include <subcmd/parse-options.h>
13 #include <subcmd/run-command.h>
14 #include <subcmd/help.h>
15 #include "util/debug.h"
16 #include <linux/kernel.h>
17 #include <errno.h>
18 #include <stdio.h>
19 #include <sys/types.h>
20 #include <sys/stat.h>
21 #include <unistd.h>
22 
23 static struct man_viewer_list {
25  char name[0];
27 
28 static struct man_viewer_info_list {
30  const char *info;
31  char name[0];
33 
39 };
40 
41 static enum help_format parse_help_format(const char *format)
42 {
43  if (!strcmp(format, "man"))
44  return HELP_FORMAT_MAN;
45  if (!strcmp(format, "info"))
46  return HELP_FORMAT_INFO;
47  if (!strcmp(format, "web") || !strcmp(format, "html"))
48  return HELP_FORMAT_WEB;
49 
50  pr_err("unrecognized help format '%s'", format);
51  return HELP_FORMAT_NONE;
52 }
53 
54 static const char *get_man_viewer_info(const char *name)
55 {
56  struct man_viewer_info_list *viewer;
57 
58  for (viewer = man_viewer_info_list; viewer; viewer = viewer->next) {
59  if (!strcasecmp(name, viewer->name))
60  return viewer->info;
61  }
62  return NULL;
63 }
64 
65 static int check_emacsclient_version(void)
66 {
67  struct strbuf buffer = STRBUF_INIT;
68  struct child_process ec_process;
69  const char *argv_ec[] = { "emacsclient", "--version", NULL };
70  int version;
71  int ret = -1;
72 
73  /* emacsclient prints its version number on stderr */
74  memset(&ec_process, 0, sizeof(ec_process));
75  ec_process.argv = argv_ec;
76  ec_process.err = -1;
77  ec_process.stdout_to_stderr = 1;
78  if (start_command(&ec_process)) {
79  fprintf(stderr, "Failed to start emacsclient.\n");
80  return -1;
81  }
82  if (strbuf_read(&buffer, ec_process.err, 20) < 0) {
83  fprintf(stderr, "Failed to read emacsclient version\n");
84  goto out;
85  }
86  close(ec_process.err);
87 
88  /*
89  * Don't bother checking return value, because "emacsclient --version"
90  * seems to always exits with code 1.
91  */
92  finish_command(&ec_process);
93 
94  if (!strstarts(buffer.buf, "emacsclient")) {
95  fprintf(stderr, "Failed to parse emacsclient version.\n");
96  goto out;
97  }
98 
99  version = atoi(buffer.buf + strlen("emacsclient"));
100 
101  if (version < 22) {
102  fprintf(stderr,
103  "emacsclient version '%d' too old (< 22).\n",
104  version);
105  } else
106  ret = 0;
107 out:
108  strbuf_release(&buffer);
109  return ret;
110 }
111 
112 static void exec_failed(const char *cmd)
113 {
114  char sbuf[STRERR_BUFSIZE];
115  pr_warning("failed to exec '%s': %s", cmd, str_error_r(errno, sbuf, sizeof(sbuf)));
116 }
117 
118 static void exec_woman_emacs(const char *path, const char *page)
119 {
120  if (!check_emacsclient_version()) {
121  /* This works only with emacsclient version >= 22. */
122  char *man_page;
123 
124  if (!path)
125  path = "emacsclient";
126  if (asprintf(&man_page, "(woman \"%s\")", page) > 0) {
127  execlp(path, "emacsclient", "-e", man_page, NULL);
128  free(man_page);
129  }
130  exec_failed(path);
131  }
132 }
133 
134 static void exec_man_konqueror(const char *path, const char *page)
135 {
136  const char *display = getenv("DISPLAY");
137 
138  if (display && *display) {
139  char *man_page;
140  const char *filename = "kfmclient";
141 
142  /* It's simpler to launch konqueror using kfmclient. */
143  if (path) {
144  const char *file = strrchr(path, '/');
145  if (file && !strcmp(file + 1, "konqueror")) {
146  char *new = strdup(path);
147  char *dest = strrchr(new, '/');
148 
149  /* strlen("konqueror") == strlen("kfmclient") */
150  strcpy(dest + 1, "kfmclient");
151  path = new;
152  }
153  if (file)
154  filename = file;
155  } else
156  path = "kfmclient";
157  if (asprintf(&man_page, "man:%s(1)", page) > 0) {
158  execlp(path, filename, "newTab", man_page, NULL);
159  free(man_page);
160  }
161  exec_failed(path);
162  }
163 }
164 
165 static void exec_man_man(const char *path, const char *page)
166 {
167  if (!path)
168  path = "man";
169  execlp(path, "man", page, NULL);
170  exec_failed(path);
171 }
172 
173 static void exec_man_cmd(const char *cmd, const char *page)
174 {
175  char *shell_cmd;
176 
177  if (asprintf(&shell_cmd, "%s %s", cmd, page) > 0) {
178  execl("/bin/sh", "sh", "-c", shell_cmd, NULL);
179  free(shell_cmd);
180  }
181  exec_failed(cmd);
182 }
183 
184 static void add_man_viewer(const char *name)
185 {
186  struct man_viewer_list **p = &man_viewer_list;
187  size_t len = strlen(name);
188 
189  while (*p)
190  p = &((*p)->next);
191  *p = zalloc(sizeof(**p) + len + 1);
192  strncpy((*p)->name, name, len);
193 }
194 
195 static int supported_man_viewer(const char *name, size_t len)
196 {
197  return (!strncasecmp("man", name, len) ||
198  !strncasecmp("woman", name, len) ||
199  !strncasecmp("konqueror", name, len));
200 }
201 
202 static void do_add_man_viewer_info(const char *name,
203  size_t len,
204  const char *value)
205 {
206  struct man_viewer_info_list *new = zalloc(sizeof(*new) + len + 1);
207 
208  strncpy(new->name, name, len);
209  new->info = strdup(value);
210  new->next = man_viewer_info_list;
211  man_viewer_info_list = new;
212 }
213 
214 static void unsupported_man_viewer(const char *name, const char *var)
215 {
216  pr_warning("'%s': path for unsupported man viewer.\n"
217  "Please consider using 'man.<tool>.%s' instead.", name, var);
218 }
219 
220 static int add_man_viewer_path(const char *name,
221  size_t len,
222  const char *value)
223 {
224  if (supported_man_viewer(name, len))
225  do_add_man_viewer_info(name, len, value);
226  else
227  unsupported_man_viewer(name, "cmd");
228 
229  return 0;
230 }
231 
232 static int add_man_viewer_cmd(const char *name,
233  size_t len,
234  const char *value)
235 {
236  if (supported_man_viewer(name, len))
237  unsupported_man_viewer(name, "path");
238  else
239  do_add_man_viewer_info(name, len, value);
240 
241  return 0;
242 }
243 
244 static int add_man_viewer_info(const char *var, const char *value)
245 {
246  const char *name = var + 4;
247  const char *subkey = strrchr(name, '.');
248 
249  if (!subkey) {
250  pr_err("Config with no key for man viewer: %s", name);
251  return -1;
252  }
253 
254  if (!strcmp(subkey, ".path")) {
255  if (!value)
256  return config_error_nonbool(var);
257  return add_man_viewer_path(name, subkey - name, value);
258  }
259  if (!strcmp(subkey, ".cmd")) {
260  if (!value)
261  return config_error_nonbool(var);
262  return add_man_viewer_cmd(name, subkey - name, value);
263  }
264 
265  pr_warning("'%s': unsupported man viewer sub key.", subkey);
266  return 0;
267 }
268 
269 static int perf_help_config(const char *var, const char *value, void *cb)
270 {
271  enum help_format *help_formatp = cb;
272 
273  if (!strcmp(var, "help.format")) {
274  if (!value)
275  return config_error_nonbool(var);
276  *help_formatp = parse_help_format(value);
277  if (*help_formatp == HELP_FORMAT_NONE)
278  return -1;
279  return 0;
280  }
281  if (!strcmp(var, "man.viewer")) {
282  if (!value)
283  return config_error_nonbool(var);
284  add_man_viewer(value);
285  return 0;
286  }
287  if (strstarts(var, "man."))
288  return add_man_viewer_info(var, value);
289 
290  return 0;
291 }
292 
293 static struct cmdnames main_cmds, other_cmds;
294 
296 {
297  unsigned int i, longest = 0;
298 
299  for (i = 0; i < ARRAY_SIZE(common_cmds); i++) {
300  if (longest < strlen(common_cmds[i].name))
301  longest = strlen(common_cmds[i].name);
302  }
303 
304  puts(" The most commonly used perf commands are:");
305  for (i = 0; i < ARRAY_SIZE(common_cmds); i++) {
306  printf(" %-*s ", longest, common_cmds[i].name);
307  puts(common_cmds[i].help);
308  }
309 }
310 
311 static const char *cmd_to_page(const char *perf_cmd)
312 {
313  char *s;
314 
315  if (!perf_cmd)
316  return "perf";
317  else if (strstarts(perf_cmd, "perf"))
318  return perf_cmd;
319 
320  return asprintf(&s, "perf-%s", perf_cmd) < 0 ? NULL : s;
321 }
322 
323 static void setup_man_path(void)
324 {
325  char *new_path;
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  if (asprintf(&new_path, "%s:%s", system_path(PERF_MAN_PATH), old_path ?: "") > 0) {
333  setenv("MANPATH", new_path, 1);
334  free(new_path);
335  } else {
336  pr_err("Unable to setup man path");
337  }
338 }
339 
340 static void exec_viewer(const char *name, const char *page)
341 {
342  const char *info = get_man_viewer_info(name);
343 
344  if (!strcasecmp(name, "man"))
345  exec_man_man(info, page);
346  else if (!strcasecmp(name, "woman"))
347  exec_woman_emacs(info, page);
348  else if (!strcasecmp(name, "konqueror"))
349  exec_man_konqueror(info, page);
350  else if (info)
351  exec_man_cmd(info, page);
352  else
353  pr_warning("'%s': unknown man viewer.", name);
354 }
355 
356 static int show_man_page(const char *perf_cmd)
357 {
358  struct man_viewer_list *viewer;
359  const char *page = cmd_to_page(perf_cmd);
360  const char *fallback = getenv("PERF_MAN_VIEWER");
361 
362  setup_man_path();
363  for (viewer = man_viewer_list; viewer; viewer = viewer->next)
364  exec_viewer(viewer->name, page); /* will return when unable */
365 
366  if (fallback)
367  exec_viewer(fallback, page);
368  exec_viewer("man", page);
369 
370  pr_err("no man viewer handled the request");
371  return -1;
372 }
373 
374 static int show_info_page(const char *perf_cmd)
375 {
376  const char *page = cmd_to_page(perf_cmd);
377  setenv("INFOPATH", system_path(PERF_INFO_PATH), 1);
378  execlp("info", "info", "perfman", page, NULL);
379  return -1;
380 }
381 
382 static int get_html_page_path(char **page_path, const char *page)
383 {
384  struct stat st;
385  const char *html_path = system_path(PERF_HTML_PATH);
386 
387  /* Check that we have a perf documentation directory. */
388  if (stat(mkpath("%s/perf.html", html_path), &st)
389  || !S_ISREG(st.st_mode)) {
390  pr_err("'%s': not a documentation directory.", html_path);
391  return -1;
392  }
393 
394  return asprintf(page_path, "%s/%s.html", html_path, page);
395 }
396 
397 /*
398  * If open_html is not defined in a platform-specific way (see for
399  * example compat/mingw.h), we use the script web--browse to display
400  * HTML.
401  */
402 #ifndef open_html
403 static void open_html(const char *path)
404 {
405  execl_cmd("web--browse", "-c", "help.browser", path, NULL);
406 }
407 #endif
408 
409 static int show_html_page(const char *perf_cmd)
410 {
411  const char *page = cmd_to_page(perf_cmd);
412  char *page_path; /* it leaks but we exec bellow */
413 
414  if (get_html_page_path(&page_path, page) < 0)
415  return -1;
416 
417  open_html(page_path);
418 
419  return 0;
420 }
421 
422 int cmd_help(int argc, const char **argv)
423 {
424  bool show_all = false;
426  struct option builtin_help_options[] = {
427  OPT_BOOLEAN('a', "all", &show_all, "print all available commands"),
428  OPT_SET_UINT('m', "man", &help_format, "show man page", HELP_FORMAT_MAN),
429  OPT_SET_UINT('w', "web", &help_format, "show manual in web browser",
431  OPT_SET_UINT('i', "info", &help_format, "show info page",
433  OPT_END(),
434  };
435  const char * const builtin_help_subcommands[] = {
436  "buildid-cache", "buildid-list", "diff", "evlist", "help", "list",
437  "record", "report", "bench", "stat", "timechart", "top", "annotate",
438  "script", "sched", "kallsyms", "kmem", "lock", "kvm", "test", "inject", "mem", "data",
439 #ifdef HAVE_LIBELF_SUPPORT
440  "probe",
441 #endif
442 #if defined(HAVE_LIBAUDIT_SUPPORT) || defined(HAVE_SYSCALL_TABLE_SUPPORT)
443  "trace",
444 #endif
445  NULL };
446  const char *builtin_help_usage[] = {
447  "perf help [--all] [--man|--web|--info] [command]",
448  NULL
449  };
450  int rc;
451 
452  load_command_list("perf-", &main_cmds, &other_cmds);
453 
454  rc = perf_config(perf_help_config, &help_format);
455  if (rc)
456  return rc;
457 
458  argc = parse_options_subcommand(argc, argv, builtin_help_options,
459  builtin_help_subcommands, builtin_help_usage, 0);
460 
461  if (show_all) {
462  printf("\n Usage: %s\n\n", perf_usage_string);
463  list_commands("perf commands", &main_cmds, &other_cmds);
464  printf(" %s\n\n", perf_more_info_string);
465  return 0;
466  }
467 
468  if (!argv[0]) {
469  printf("\n usage: %s\n\n", perf_usage_string);
471  printf("\n %s\n\n", perf_more_info_string);
472  return 0;
473  }
474 
475  switch (help_format) {
476  case HELP_FORMAT_MAN:
477  rc = show_man_page(argv[0]);
478  break;
479  case HELP_FORMAT_INFO:
480  rc = show_info_page(argv[0]);
481  break;
482  case HELP_FORMAT_WEB:
483  rc = show_html_page(argv[0]);
484  break;
485  case HELP_FORMAT_NONE:
486  /* fall-through */
487  default:
488  rc = -1;
489  break;
490  }
491 
492  return rc;
493 }
static const char * cmd_to_page(const char *perf_cmd)
Definition: builtin-help.c:311
Definition: strbuf.h:50
help_format
Definition: builtin-help.c:34
const char perf_usage_string[]
Definition: perf.c:33
int value
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const char perf_more_info_string[]
Definition: perf.c:36
static void setup_man_path(void)
Definition: builtin-help.c:323
static void exec_man_cmd(const char *cmd, const char *page)
Definition: builtin-help.c:173
static void open_html(const char *path)
Definition: builtin-help.c:403
static struct version version
const char * filename
Definition: hists_common.c:26
static int add_man_viewer_info(const char *var, const char *value)
Definition: builtin-help.c:244
static struct cmdnames main_cmds other_cmds
Definition: builtin-help.c:293
static struct man_viewer_info_list * man_viewer_info_list
struct man_viewer_info_list * next
Definition: builtin-help.c:29
static int show_man_page(const char *perf_cmd)
Definition: builtin-help.c:356
static int add_man_viewer_cmd(const char *name, size_t len, const char *value)
Definition: builtin-help.c:232
static int show_html_page(const char *perf_cmd)
Definition: builtin-help.c:409
static int show_info_page(const char *perf_cmd)
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const char * info
Definition: builtin-help.c:30
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Definition: builtin-help.c:382
char * buf
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Definition: builtin-help.c:24
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static void add_man_viewer(const char *name)
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static enum help_format parse_help_format(const char *format)
Definition: builtin-help.c:41
int perf_config(config_fn_t fn, void *data)
Definition: config.c:718
static struct man_viewer_list * man_viewer_list
#define STRERR_BUFSIZE
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void free(void *)
int cmd_help(int argc, const char **argv)
Definition: builtin-help.c:422
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static void do_add_man_viewer_info(const char *name, size_t len, const char *value)
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void strbuf_release(struct strbuf *sb)
Definition: strbuf.c:23
static void exec_man_man(const char *path, const char *page)
Definition: builtin-help.c:165
static int perf_help_config(const char *var, const char *value, void *cb)
Definition: builtin-help.c:269
static int check_emacsclient_version(void)
Definition: builtin-help.c:65
static void exec_woman_emacs(const char *path, const char *page)
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