builtin/help.c

   1 /*
   2  * Builtin help command
   3  */
   4 #include "cache.h"
   5 #include "config.h"
   6 #include "builtin.h"
   7 #include "exec-cmd.h"
   8 #include "parse-options.h"
   9 #include "run-command.h"
  10 #include "column.h"
  11 #include "help.h"
  12 #include "alias.h"
  13
  14 #ifndef DEFAULT_HELP_FORMAT
  15 #define DEFAULT_HELP_FORMAT "man"
  16 #endif
  17
  18 static struct man_viewer_list {
  19         struct man_viewer_list *next;
  20         char name[FLEX_ARRAY];
  21 } *man_viewer_list;
  22
  23 static struct man_viewer_info_list {
  24         struct man_viewer_info_list *next;
  25         const char *info;
  26         char name[FLEX_ARRAY];
  27 } *man_viewer_info_list;
  28
  29 enum help_format {
  30         HELP_FORMAT_NONE,
  31         HELP_FORMAT_MAN,
  32         HELP_FORMAT_INFO,
  33         HELP_FORMAT_WEB
  34 };
  35
  36 static const char *html_path;
  37
  38 static int show_all = 0;
  39 static int show_guides = 0;
  40 static int show_config;
  41 static int verbose = 1;
  42 static unsigned int colopts;
  43 static enum help_format help_format = HELP_FORMAT_NONE;
  44 static int exclude_guides;
  45 static struct option builtin_help_options[] = {
  46         OPT_BOOL('a', "all", &show_all, N_("print all available commands")),
  47         OPT_HIDDEN_BOOL(0, "exclude-guides", &exclude_guides, N_("exclude guides")),
  48         OPT_BOOL('g', "guides", &show_guides, N_("print list of useful guides")),
  49         OPT_BOOL('c', "config", &show_config, N_("print all configuration variable names")),
  50         OPT_SET_INT_F(0, "config-for-completion", &show_config, "", 2, PARSE_OPT_HIDDEN),
  51         OPT_SET_INT('m', "man", &help_format, N_("show man page"), HELP_FORMAT_MAN),
  52         OPT_SET_INT('w', "web", &help_format, N_("show manual in web browser"),
  53                         HELP_FORMAT_WEB),
  54         OPT_SET_INT('i', "info", &help_format, N_("show info page"),
  55                         HELP_FORMAT_INFO),
  56         OPT__VERBOSE(&verbose, N_("print command description")),
  57         OPT_END(),
  58 };
  59
  60 static const char * const builtin_help_usage[] = {
  61         N_("git help [--all] [--guides] [--man | --web | --info] [<command>]"),
  62         NULL
  63 };
  64
  65 static enum help_format parse_help_format(const char *format)
  66 {
  67         if (!strcmp(format, "man"))
  68                 return HELP_FORMAT_MAN;
  69         if (!strcmp(format, "info"))
  70                 return HELP_FORMAT_INFO;
  71         if (!strcmp(format, "web") || !strcmp(format, "html"))
  72                 return HELP_FORMAT_WEB;
  73         die(_("unrecognized help format '%s'"), format);
  74 }
  75
  76 static const char *get_man_viewer_info(const char *name)
  77 {
  78         struct man_viewer_info_list *viewer;
  79
  80         for (viewer = man_viewer_info_list; viewer; viewer = viewer->next)
  81         {
  82                 if (!strcasecmp(name, viewer->name))
  83                         return viewer->info;
  84         }
  85         return NULL;
  86 }
  87
  88 static int check_emacsclient_version(void)
  89 {
  90         struct strbuf buffer = STRBUF_INIT;
  91         struct child_process ec_process = CHILD_PROCESS_INIT;
  92         const char *argv_ec[] = { "emacsclient", "--version", NULL };
  93         int version;
  94
  95         /* emacsclient prints its version number on stderr */
  96         ec_process.argv = argv_ec;
  97         ec_process.err = -1;
  98         ec_process.stdout_to_stderr = 1;
  99         if (start_command(&ec_process))
 100                 return error(_("Failed to start emacsclient."));
 101
 102         strbuf_read(&buffer, ec_process.err, 20);
 103         close(ec_process.err);
 104
 105         /*
 106          * Don't bother checking return value, because "emacsclient --version"
 107          * seems to always exits with code 1.
 108          */
 109         finish_command(&ec_process);
 110
 111         if (!starts_with(buffer.buf, "emacsclient")) {
 112                 strbuf_release(&buffer);
 113                 return error(_("Failed to parse emacsclient version."));
 114         }
 115
 116         strbuf_remove(&buffer, 0, strlen("emacsclient"));
 117         version = atoi(buffer.buf);
 118
 119         if (version < 22) {
 120                 strbuf_release(&buffer);
 121                 return error(_("emacsclient version '%d' too old (< 22)."),
 122                         version);
 123         }
 124
 125         strbuf_release(&buffer);
 126         return 0;
 127 }
 128
 129 static void exec_woman_emacs(const char *path, const char *page)
 130 {
 131         if (!check_emacsclient_version()) {
 132                 /* This works only with emacsclient version >= 22. */
 133                 struct strbuf man_page = STRBUF_INIT;
 134
 135                 if (!path)
 136                         path = "emacsclient";
 137                 strbuf_addf(&man_page, "(woman \"%s\")", page);
 138                 execlp(path, "emacsclient", "-e", man_page.buf, (char *)NULL);
 139                 warning_errno(_("failed to exec '%s'"), path);
 140                 strbuf_release(&man_page);
 141         }
 142 }
 143
 144 static void exec_man_konqueror(const char *path, const char *page)
 145 {
 146         const char *display = getenv("DISPLAY");
 147         if (display && *display) {
 148                 struct strbuf man_page = STRBUF_INIT;
 149                 const char *filename = "kfmclient";
 150
 151                 /* It's simpler to launch konqueror using kfmclient. */
 152                 if (path) {
 153                         size_t len;
 154                         if (strip_suffix(path, "/konqueror", &len))
 155                                 path = xstrfmt("%.*s/kfmclient", (int)len, path);
 156                         filename = basename((char *)path);
 157                 } else
 158                         path = "kfmclient";
 159                 strbuf_addf(&man_page, "man:%s(1)", page);
 160                 execlp(path, filename, "newTab", man_page.buf, (char *)NULL);
 161                 warning_errno(_("failed to exec '%s'"), path);
 162                 strbuf_release(&man_page);
 163         }
 164 }
 165
 166 static void exec_man_man(const char *path, const char *page)
 167 {
 168         if (!path)
 169                 path = "man";
 170         execlp(path, "man", page, (char *)NULL);
 171         warning_errno(_("failed to exec '%s'"), path);
 172 }
 173
 174 static void exec_man_cmd(const char *cmd, const char *page)
 175 {
 176         struct strbuf shell_cmd = STRBUF_INIT;
 177         strbuf_addf(&shell_cmd, "%s %s", cmd, page);
 178         execl(SHELL_PATH, SHELL_PATH, "-c", shell_cmd.buf, (char *)NULL);
 179         warning(_("failed to exec '%s'"), cmd);
 180         strbuf_release(&shell_cmd);
 181 }
 182
 183 static void add_man_viewer(const char *name)
 184 {
 185         struct man_viewer_list **p = &man_viewer_list;
 186
 187         while (*p)
 188                 p = &((*p)->next);
 189         FLEX_ALLOC_STR(*p, name, name);
 190 }
 191
 192 static int supported_man_viewer(const char *name, size_t len)
 193 {
 194         return (!strncasecmp("man", name, len) ||
 195                 !strncasecmp("woman", name, len) ||
 196                 !strncasecmp("konqueror", name, len));
 197 }
 198
 199 static void do_add_man_viewer_info(const char *name,
 200                                    size_t len,
 201                                    const char *value)
 202 {
 203         struct man_viewer_info_list *new_man_viewer;
 204         FLEX_ALLOC_MEM(new_man_viewer, name, name, len);
 205         new_man_viewer->info = xstrdup(value);
 206         new_man_viewer->next = man_viewer_info_list;
 207         man_viewer_info_list = new_man_viewer;
 208 }
 209
 210 static int add_man_viewer_path(const char *name,
 211                                size_t len,
 212                                const char *value)
 213 {
 214         if (supported_man_viewer(name, len))
 215                 do_add_man_viewer_info(name, len, value);
 216         else
 217                 warning(_("'%s': path for unsupported man viewer.\n"
 218                           "Please consider using 'man.<tool>.cmd' instead."),
 219                         name);
 220
 221         return 0;
 222 }
 223
 224 static int add_man_viewer_cmd(const char *name,
 225                               size_t len,
 226                               const char *value)
 227 {
 228         if (supported_man_viewer(name, len))
 229                 warning(_("'%s': cmd for supported man viewer.\n"
 230                           "Please consider using 'man.<tool>.path' instead."),
 231                         name);
 232         else
 233                 do_add_man_viewer_info(name, len, value);
 234
 235         return 0;
 236 }
 237
 238 static int add_man_viewer_info(const char *var, const char *value)
 239 {
 240         const char *name, *subkey;
 241         int namelen;
 242
 243         if (parse_config_key(var, "man", &name, &namelen, &subkey) < 0 || !name)
 244                 return 0;
 245
 246         if (!strcmp(subkey, "path")) {
 247                 if (!value)
 248                         return config_error_nonbool(var);
 249                 return add_man_viewer_path(name, namelen, value);
 250         }
 251         if (!strcmp(subkey, "cmd")) {
 252                 if (!value)
 253                         return config_error_nonbool(var);
 254                 return add_man_viewer_cmd(name, namelen, value);
 255         }
 256
 257         return 0;
 258 }
 259
 260 static int git_help_config(const char *var, const char *value, void *cb)
 261 {
 262         if (starts_with(var, "column."))
 263                 return git_column_config(var, value, "help", &colopts);
 264         if (!strcmp(var, "help.format")) {
 265                 if (!value)
 266                         return config_error_nonbool(var);
 267                 help_format = parse_help_format(value);
 268                 return 0;
 269         }
 270         if (!strcmp(var, "help.htmlpath")) {
 271                 if (!value)
 272                         return config_error_nonbool(var);
 273                 html_path = xstrdup(value);
 274                 return 0;
 275         }
 276         if (!strcmp(var, "man.viewer")) {
 277                 if (!value)
 278                         return config_error_nonbool(var);
 279                 add_man_viewer(value);
 280                 return 0;
 281         }
 282         if (starts_with(var, "man."))
 283                 return add_man_viewer_info(var, value);
 284
 285         return git_default_config(var, value, cb);
 286 }
 287
 288 static struct cmdnames main_cmds, other_cmds;
 289
 290 static int is_git_command(const char *s)
 291 {
 292         if (is_builtin(s))
 293                 return 1;
 294
 295         load_command_list("git-", &main_cmds, &other_cmds);
 296         return is_in_cmdlist(&main_cmds, s) ||
 297                 is_in_cmdlist(&other_cmds, s);
 298 }
 299
 300 static const char *cmd_to_page(const char *git_cmd)
 301 {
 302         if (!git_cmd)
 303                 return "git";
 304         else if (starts_with(git_cmd, "git"))
 305                 return git_cmd;
 306         else if (is_git_command(git_cmd))
 307                 return xstrfmt("git-%s", git_cmd);
 308         else
 309                 return xstrfmt("git%s", git_cmd);
 310 }
 311
 312 static void setup_man_path(void)
 313 {
 314         struct strbuf new_path = STRBUF_INIT;
 315         const char *old_path = getenv("MANPATH");
 316         char *git_man_path = system_path(GIT_MAN_PATH);
 317
 318         /* We should always put ':' after our path. If there is no
 319          * old_path, the ':' at the end will let 'man' to try
 320          * system-wide paths after ours to find the manual page. If
 321          * there is old_path, we need ':' as delimiter. */
 322         strbuf_addstr(&new_path, git_man_path);
 323         strbuf_addch(&new_path, ':');
 324         if (old_path)
 325                 strbuf_addstr(&new_path, old_path);
 326
 327         free(git_man_path);
 328         setenv("MANPATH", new_path.buf, 1);
 329
 330         strbuf_release(&new_path);
 331 }
 332
 333 static void exec_viewer(const char *name, const char *page)
 334 {
 335         const char *info = get_man_viewer_info(name);
 336
 337         if (!strcasecmp(name, "man"))
 338                 exec_man_man(info, page);
 339         else if (!strcasecmp(name, "woman"))
 340                 exec_woman_emacs(info, page);
 341         else if (!strcasecmp(name, "konqueror"))
 342                 exec_man_konqueror(info, page);
 343         else if (info)
 344                 exec_man_cmd(info, page);
 345         else
 346                 warning(_("'%s': unknown man viewer."), name);
 347 }
 348
 349 static void show_man_page(const char *git_cmd)
 350 {
 351         struct man_viewer_list *viewer;
 352         const char *page = cmd_to_page(git_cmd);
 353         const char *fallback = getenv("GIT_MAN_VIEWER");
 354
 355         setup_man_path();
 356         for (viewer = man_viewer_list; viewer; viewer = viewer->next)
 357         {
 358                 exec_viewer(viewer->name, page); /* will return when unable */
 359         }
 360         if (fallback)
 361                 exec_viewer(fallback, page);
 362         exec_viewer("man", page);
 363         die(_("no man viewer handled the request"));
 364 }
 365
 366 static void show_info_page(const char *git_cmd)
 367 {
 368         const char *page = cmd_to_page(git_cmd);
 369         setenv("INFOPATH", system_path(GIT_INFO_PATH), 1);
 370         execlp("info", "info", "gitman", page, (char *)NULL);
 371         die(_("no info viewer handled the request"));
 372 }
 373
 374 static void get_html_page_path(struct strbuf *page_path, const char *page)
 375 {
 376         struct stat st;
 377         char *to_free = NULL;
 378
 379         if (!html_path)
 380                 html_path = to_free = system_path(GIT_HTML_PATH);
 381
 382         /* Check that we have a git documentation directory. */
 383         if (!strstr(html_path, "://")) {
 384                 if (stat(mkpath("%s/git.html", html_path), &st)
 385                     || !S_ISREG(st.st_mode))
 386                         die("'%s': not a documentation directory.", html_path);
 387         }
 388
 389         strbuf_init(page_path, 0);
 390         strbuf_addf(page_path, "%s/%s.html", html_path, page);
 391         free(to_free);
 392 }
 393
 394 static void open_html(const char *path)
 395 {
 396         execl_git_cmd("web--browse", "-c", "help.browser", path, (char *)NULL);
 397 }
 398
 399 static void show_html_page(const char *git_cmd)
 400 {
 401         const char *page = cmd_to_page(git_cmd);
 402         struct strbuf page_path; /* it leaks but we exec bellow */
 403
 404         get_html_page_path(&page_path, page);
 405
 406         open_html(page_path.buf);
 407 }
 408
 409 static const char *check_git_cmd(const char* cmd)
 410 {
 411         char *alias;
 412
 413         if (is_git_command(cmd))
 414                 return cmd;
 415
 416         alias = alias_lookup(cmd);
 417         if (alias) {
 418                 const char **argv;
 419                 int count;
 420
 421                 /*
 422                  * handle_builtin() in git.c rewrites "git cmd --help"
 423                  * to "git help --exclude-guides cmd", so we can use
 424                  * exclude_guides to distinguish "git cmd --help" from
 425                  * "git help cmd". In the latter case, or if cmd is an
 426                  * alias for a shell command, just print the alias
 427                  * definition.
 428                  */
 429                 if (!exclude_guides || alias[0] == '!') {
 430                         printf_ln(_("'%s' is aliased to '%s'"), cmd, alias);
 431                         free(alias);
 432                         exit(0);
 433                 }
 434                 /*
 435                  * Otherwise, we pretend that the command was "git
 436                  * word0 --help". We use split_cmdline() to get the
 437                  * first word of the alias, to ensure that we use the
 438                  * same rules as when the alias is actually
 439                  * used. split_cmdline() modifies alias in-place.
 440                  */
 441                 fprintf_ln(stderr, _("'%s' is aliased to '%s'"), cmd, alias);
 442                 count = split_cmdline(alias, &argv);
 443                 if (count < 0)
 444                         die(_("bad alias.%s string: %s"), cmd,
 445                             split_cmdline_strerror(count));
 446                 free(argv);
 447                 UNLEAK(alias);
 448                 return alias;
 449         }
 450
 451         if (exclude_guides)
 452                 return help_unknown_cmd(cmd);
 453
 454         return cmd;
 455 }
 456
 457 int cmd_help(int argc, const char **argv, const char *prefix)
 458 {
 459         int nongit;
 460         enum help_format parsed_help_format;
 461
 462         argc = parse_options(argc, argv, prefix, builtin_help_options,
 463                         builtin_help_usage, 0);
 464         parsed_help_format = help_format;
 465
 466         if (show_all) {
 467                 git_config(git_help_config, NULL);
 468                 if (verbose) {
 469                         setup_pager();
 470                         list_all_cmds_help();
 471                         return 0;
 472                 }
 473                 printf(_("usage: %s%s"), _(git_usage_string), "\n\n");
 474                 load_command_list("git-", &main_cmds, &other_cmds);
 475                 list_commands(colopts, &main_cmds, &other_cmds);
 476         }
 477
 478         if (show_config) {
 479                 int for_human = show_config == 1;
 480
 481                 if (!for_human) {
 482                         list_config_help(for_human);
 483                         return 0;
 484                 }
 485                 setup_pager();
 486                 list_config_help(for_human);
 487                 printf("\n%s\n", _("'git help config' for more information"));
 488                 return 0;
 489         }
 490
 491         if (show_guides)
 492                 list_common_guides_help();
 493
 494         if (show_all || show_guides) {
 495                 printf("%s\n", _(git_more_info_string));
 496                 /*
 497                 * We're done. Ignore any remaining args
 498                 */
 499                 return 0;
 500         }
 501
 502         if (!argv[0]) {
 503                 printf(_("usage: %s%s"), _(git_usage_string), "\n\n");
 504                 list_common_cmds_help();
 505                 printf("\n%s\n", _(git_more_info_string));
 506                 return 0;
 507         }
 508
 509         setup_git_directory_gently(&nongit);
 510         git_config(git_help_config, NULL);
 511
 512         if (parsed_help_format != HELP_FORMAT_NONE)
 513                 help_format = parsed_help_format;
 514         if (help_format == HELP_FORMAT_NONE)
 515                 help_format = parse_help_format(DEFAULT_HELP_FORMAT);
 516
 517         argv[0] = check_git_cmd(argv[0]);
 518
 519         switch (help_format) {
 520         case HELP_FORMAT_NONE:
 521         case HELP_FORMAT_MAN:
 522                 show_man_page(argv[0]);
 523                 break;
 524         case HELP_FORMAT_INFO:
 525                 show_info_page(argv[0]);
 526                 break;
 527         case HELP_FORMAT_WEB:
 528                 show_html_page(argv[0]);
 529                 break;
 530         }
 531
 532         return 0;
 533 }