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         /*
  74          * Please update _git_config() in git-completion.bash when you
  75          * add new help formats.
  76          */
  77         die(_("unrecognized help format '%s'"), format);
  78 }
  79
  80 static const char *get_man_viewer_info(const char *name)
  81 {
  82         struct man_viewer_info_list *viewer;
  83
  84         for (viewer = man_viewer_info_list; viewer; viewer = viewer->next)
  85         {
  86                 if (!strcasecmp(name, viewer->name))
  87                         return viewer->info;
  88         }
  89         return NULL;
  90 }
  91
  92 static int check_emacsclient_version(void)
  93 {
  94         struct strbuf buffer = STRBUF_INIT;
  95         struct child_process ec_process = CHILD_PROCESS_INIT;
  96         const char *argv_ec[] = { "emacsclient", "--version", NULL };
  97         int version;
  98
  99         /* emacsclient prints its version number on stderr */
 100         ec_process.argv = argv_ec;
 101         ec_process.err = -1;
 102         ec_process.stdout_to_stderr = 1;
 103         if (start_command(&ec_process))
 104                 return error(_("Failed to start emacsclient."));
 105
 106         strbuf_read(&buffer, ec_process.err, 20);
 107         close(ec_process.err);
 108
 109         /*
 110          * Don't bother checking return value, because "emacsclient --version"
 111          * seems to always exits with code 1.
 112          */
 113         finish_command(&ec_process);
 114
 115         if (!starts_with(buffer.buf, "emacsclient")) {
 116                 strbuf_release(&buffer);
 117                 return error(_("Failed to parse emacsclient version."));
 118         }
 119
 120         strbuf_remove(&buffer, 0, strlen("emacsclient"));
 121         version = atoi(buffer.buf);
 122
 123         if (version < 22) {
 124                 strbuf_release(&buffer);
 125                 return error(_("emacsclient version '%d' too old (< 22)."),
 126                         version);
 127         }
 128
 129         strbuf_release(&buffer);
 130         return 0;
 131 }
 132
 133 static void exec_woman_emacs(const char *path, const char *page)
 134 {
 135         if (!check_emacsclient_version()) {
 136                 /* This works only with emacsclient version >= 22. */
 137                 struct strbuf man_page = STRBUF_INIT;
 138
 139                 if (!path)
 140                         path = "emacsclient";
 141                 strbuf_addf(&man_page, "(woman \"%s\")", page);
 142                 execlp(path, "emacsclient", "-e", man_page.buf, (char *)NULL);
 143                 warning_errno(_("failed to exec '%s'"), path);
 144                 strbuf_release(&man_page);
 145         }
 146 }
 147
 148 static void exec_man_konqueror(const char *path, const char *page)
 149 {
 150         const char *display = getenv("DISPLAY");
 151         if (display && *display) {
 152                 struct strbuf man_page = STRBUF_INIT;
 153                 const char *filename = "kfmclient";
 154
 155                 /* It's simpler to launch konqueror using kfmclient. */
 156                 if (path) {
 157                         size_t len;
 158                         if (strip_suffix(path, "/konqueror", &len))
 159                                 path = xstrfmt("%.*s/kfmclient", (int)len, path);
 160                         filename = basename((char *)path);
 161                 } else
 162                         path = "kfmclient";
 163                 strbuf_addf(&man_page, "man:%s(1)", page);
 164                 execlp(path, filename, "newTab", man_page.buf, (char *)NULL);
 165                 warning_errno(_("failed to exec '%s'"), path);
 166                 strbuf_release(&man_page);
 167         }
 168 }
 169
 170 static void exec_man_man(const char *path, const char *page)
 171 {
 172         if (!path)
 173                 path = "man";
 174         execlp(path, "man", page, (char *)NULL);
 175         warning_errno(_("failed to exec '%s'"), path);
 176 }
 177
 178 static void exec_man_cmd(const char *cmd, const char *page)
 179 {
 180         struct strbuf shell_cmd = STRBUF_INIT;
 181         strbuf_addf(&shell_cmd, "%s %s", cmd, page);
 182         execl(SHELL_PATH, SHELL_PATH, "-c", shell_cmd.buf, (char *)NULL);
 183         warning(_("failed to exec '%s'"), cmd);
 184         strbuf_release(&shell_cmd);
 185 }
 186
 187 static void add_man_viewer(const char *name)
 188 {
 189         struct man_viewer_list **p = &man_viewer_list;
 190
 191         while (*p)
 192                 p = &((*p)->next);
 193         FLEX_ALLOC_STR(*p, name, name);
 194 }
 195
 196 static int supported_man_viewer(const char *name, size_t len)
 197 {
 198         return (!strncasecmp("man", name, len) ||
 199                 !strncasecmp("woman", name, len) ||
 200                 !strncasecmp("konqueror", name, len));
 201 }
 202
 203 static void do_add_man_viewer_info(const char *name,
 204                                    size_t len,
 205                                    const char *value)
 206 {
 207         struct man_viewer_info_list *new_man_viewer;
 208         FLEX_ALLOC_MEM(new_man_viewer, name, name, len);
 209         new_man_viewer->info = xstrdup(value);
 210         new_man_viewer->next = man_viewer_info_list;
 211         man_viewer_info_list = new_man_viewer;
 212 }
 213
 214 static int add_man_viewer_path(const char *name,
 215                                size_t len,
 216                                const char *value)
 217 {
 218         if (supported_man_viewer(name, len))
 219                 do_add_man_viewer_info(name, len, value);
 220         else
 221                 warning(_("'%s': path for unsupported man viewer.\n"
 222                           "Please consider using 'man.<tool>.cmd' instead."),
 223                         name);
 224
 225         return 0;
 226 }
 227
 228 static int add_man_viewer_cmd(const char *name,
 229                               size_t len,
 230                               const char *value)
 231 {
 232         if (supported_man_viewer(name, len))
 233                 warning(_("'%s': cmd for supported man viewer.\n"
 234                           "Please consider using 'man.<tool>.path' instead."),
 235                         name);
 236         else
 237                 do_add_man_viewer_info(name, len, value);
 238
 239         return 0;
 240 }
 241
 242 static int add_man_viewer_info(const char *var, const char *value)
 243 {
 244         const char *name, *subkey;
 245         int namelen;
 246
 247         if (parse_config_key(var, "man", &name, &namelen, &subkey) < 0 || !name)
 248                 return 0;
 249
 250         if (!strcmp(subkey, "path")) {
 251                 if (!value)
 252                         return config_error_nonbool(var);
 253                 return add_man_viewer_path(name, namelen, value);
 254         }
 255         if (!strcmp(subkey, "cmd")) {
 256                 if (!value)
 257                         return config_error_nonbool(var);
 258                 return add_man_viewer_cmd(name, namelen, value);
 259         }
 260
 261         return 0;
 262 }
 263
 264 static int git_help_config(const char *var, const char *value, void *cb)
 265 {
 266         if (starts_with(var, "column."))
 267                 return git_column_config(var, value, "help", &colopts);
 268         if (!strcmp(var, "help.format")) {
 269                 if (!value)
 270                         return config_error_nonbool(var);
 271                 help_format = parse_help_format(value);
 272                 return 0;
 273         }
 274         if (!strcmp(var, "help.htmlpath")) {
 275                 if (!value)
 276                         return config_error_nonbool(var);
 277                 html_path = xstrdup(value);
 278                 return 0;
 279         }
 280         if (!strcmp(var, "man.viewer")) {
 281                 if (!value)
 282                         return config_error_nonbool(var);
 283                 add_man_viewer(value);
 284                 return 0;
 285         }
 286         if (starts_with(var, "man."))
 287                 return add_man_viewer_info(var, value);
 288
 289         return git_default_config(var, value, cb);
 290 }
 291
 292 static struct cmdnames main_cmds, other_cmds;
 293
 294 static int is_git_command(const char *s)
 295 {
 296         if (is_builtin(s))
 297                 return 1;
 298
 299         load_command_list("git-", &main_cmds, &other_cmds);
 300         return is_in_cmdlist(&main_cmds, s) ||
 301                 is_in_cmdlist(&other_cmds, s);
 302 }
 303
 304 static const char *cmd_to_page(const char *git_cmd)
 305 {
 306         if (!git_cmd)
 307                 return "git";
 308         else if (starts_with(git_cmd, "git"))
 309                 return git_cmd;
 310         else if (is_git_command(git_cmd))
 311                 return xstrfmt("git-%s", git_cmd);
 312         else
 313                 return xstrfmt("git%s", git_cmd);
 314 }
 315
 316 static void setup_man_path(void)
 317 {
 318         struct strbuf new_path = STRBUF_INIT;
 319         const char *old_path = getenv("MANPATH");
 320         char *git_man_path = system_path(GIT_MAN_PATH);
 321
 322         /* We should always put ':' after our path. If there is no
 323          * old_path, the ':' at the end will let 'man' to try
 324          * system-wide paths after ours to find the manual page. If
 325          * there is old_path, we need ':' as delimiter. */
 326         strbuf_addstr(&new_path, git_man_path);
 327         strbuf_addch(&new_path, ':');
 328         if (old_path)
 329                 strbuf_addstr(&new_path, old_path);
 330
 331         free(git_man_path);
 332         setenv("MANPATH", new_path.buf, 1);
 333
 334         strbuf_release(&new_path);
 335 }
 336
 337 static void exec_viewer(const char *name, const char *page)
 338 {
 339         const char *info = get_man_viewer_info(name);
 340
 341         if (!strcasecmp(name, "man"))
 342                 exec_man_man(info, page);
 343         else if (!strcasecmp(name, "woman"))
 344                 exec_woman_emacs(info, page);
 345         else if (!strcasecmp(name, "konqueror"))
 346                 exec_man_konqueror(info, page);
 347         else if (info)
 348                 exec_man_cmd(info, page);
 349         else
 350                 warning(_("'%s': unknown man viewer."), name);
 351 }
 352
 353 static void show_man_page(const char *git_cmd)
 354 {
 355         struct man_viewer_list *viewer;
 356         const char *page = cmd_to_page(git_cmd);
 357         const char *fallback = getenv("GIT_MAN_VIEWER");
 358
 359         setup_man_path();
 360         for (viewer = man_viewer_list; viewer; viewer = viewer->next)
 361         {
 362                 exec_viewer(viewer->name, page); /* will return when unable */
 363         }
 364         if (fallback)
 365                 exec_viewer(fallback, page);
 366         exec_viewer("man", page);
 367         die(_("no man viewer handled the request"));
 368 }
 369
 370 static void show_info_page(const char *git_cmd)
 371 {
 372         const char *page = cmd_to_page(git_cmd);
 373         setenv("INFOPATH", system_path(GIT_INFO_PATH), 1);
 374         execlp("info", "info", "gitman", page, (char *)NULL);
 375         die(_("no info viewer handled the request"));
 376 }
 377
 378 static void get_html_page_path(struct strbuf *page_path, const char *page)
 379 {
 380         struct stat st;
 381         char *to_free = NULL;
 382
 383         if (!html_path)
 384                 html_path = to_free = system_path(GIT_HTML_PATH);
 385
 386         /* Check that we have a git documentation directory. */
 387         if (!strstr(html_path, "://")) {
 388                 if (stat(mkpath("%s/git.html", html_path), &st)
 389                     || !S_ISREG(st.st_mode))
 390                         die("'%s': not a documentation directory.", html_path);
 391         }
 392
 393         strbuf_init(page_path, 0);
 394         strbuf_addf(page_path, "%s/%s.html", html_path, page);
 395         free(to_free);
 396 }
 397
 398 static void open_html(const char *path)
 399 {
 400         execl_git_cmd("web--browse", "-c", "help.browser", path, (char *)NULL);
 401 }
 402
 403 static void show_html_page(const char *git_cmd)
 404 {
 405         const char *page = cmd_to_page(git_cmd);
 406         struct strbuf page_path; /* it leaks but we exec bellow */
 407
 408         get_html_page_path(&page_path, page);
 409
 410         open_html(page_path.buf);
 411 }
 412
 413 static const char *check_git_cmd(const char* cmd)
 414 {
 415         char *alias;
 416
 417         if (is_git_command(cmd))
 418                 return cmd;
 419
 420         alias = alias_lookup(cmd);
 421         if (alias) {
 422                 const char **argv;
 423                 int count;
 424
 425                 /*
 426                  * handle_builtin() in git.c rewrites "git cmd --help"
 427                  * to "git help --exclude-guides cmd", so we can use
 428                  * exclude_guides to distinguish "git cmd --help" from
 429                  * "git help cmd". In the latter case, or if cmd is an
 430                  * alias for a shell command, just print the alias
 431                  * definition.
 432                  */
 433                 if (!exclude_guides || alias[0] == '!') {
 434                         printf_ln(_("'%s' is aliased to '%s'"), cmd, alias);
 435                         free(alias);
 436                         exit(0);
 437                 }
 438                 /*
 439                  * Otherwise, we pretend that the command was "git
 440                  * word0 --help". We use split_cmdline() to get the
 441                  * first word of the alias, to ensure that we use the
 442                  * same rules as when the alias is actually
 443                  * used. split_cmdline() modifies alias in-place.
 444                  */
 445                 fprintf_ln(stderr, _("'%s' is aliased to '%s'"), cmd, alias);
 446                 count = split_cmdline(alias, &argv);
 447                 if (count < 0)
 448                         die(_("bad alias.%s string: %s"), cmd,
 449                             split_cmdline_strerror(count));
 450                 free(argv);
 451                 UNLEAK(alias);
 452                 return alias;
 453         }
 454
 455         if (exclude_guides)
 456                 return help_unknown_cmd(cmd);
 457
 458         return cmd;
 459 }
 460
 461 int cmd_help(int argc, const char **argv, const char *prefix)
 462 {
 463         int nongit;
 464         enum help_format parsed_help_format;
 465
 466         argc = parse_options(argc, argv, prefix, builtin_help_options,
 467                         builtin_help_usage, 0);
 468         parsed_help_format = help_format;
 469
 470         if (show_all) {
 471                 git_config(git_help_config, NULL);
 472                 if (verbose) {
 473                         setup_pager();
 474                         list_all_cmds_help();
 475                         return 0;
 476                 }
 477                 printf(_("usage: %s%s"), _(git_usage_string), "\n\n");
 478                 load_command_list("git-", &main_cmds, &other_cmds);
 479                 list_commands(colopts, &main_cmds, &other_cmds);
 480         }
 481
 482         if (show_config) {
 483                 int for_human = show_config == 1;
 484
 485                 if (!for_human) {
 486                         list_config_help(for_human);
 487                         return 0;
 488                 }
 489                 setup_pager();
 490                 list_config_help(for_human);
 491                 printf("\n%s\n", _("'git help config' for more information"));
 492                 return 0;
 493         }
 494
 495         if (show_guides)
 496                 list_common_guides_help();
 497
 498         if (show_all || show_guides) {
 499                 printf("%s\n", _(git_more_info_string));
 500                 /*
 501                 * We're done. Ignore any remaining args
 502                 */
 503                 return 0;
 504         }
 505
 506         if (!argv[0]) {
 507                 printf(_("usage: %s%s"), _(git_usage_string), "\n\n");
 508                 list_common_cmds_help();
 509                 printf("\n%s\n", _(git_more_info_string));
 510                 return 0;
 511         }
 512
 513         setup_git_directory_gently(&nongit);
 514         git_config(git_help_config, NULL);
 515
 516         if (parsed_help_format != HELP_FORMAT_NONE)
 517                 help_format = parsed_help_format;
 518         if (help_format == HELP_FORMAT_NONE)
 519                 help_format = parse_help_format(DEFAULT_HELP_FORMAT);
 520
 521         argv[0] = check_git_cmd(argv[0]);
 522
 523         switch (help_format) {
 524         case HELP_FORMAT_NONE:
 525         case HELP_FORMAT_MAN:
 526                 show_man_page(argv[0]);
 527                 break;
 528         case HELP_FORMAT_INFO:
 529                 show_info_page(argv[0]);
 530                 break;
 531         case HELP_FORMAT_WEB:
 532                 show_html_page(argv[0]);
 533                 break;
 534         }
 535
 536         return 0;
 537 }