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   1 /*
   2  * builtin-help.c
   3  *
   4  * Builtin help command
   5  */
   6 #include "cache.h"
   7 #include "builtin.h"
   8 #include "exec_cmd.h"
   9 #include "common-cmds.h"
  10 #include "parse-options.h"
  11 #include "run-command.h"
  12 #include "column.h"
  13 #include "help.h"
  14
  15 static struct man_viewer_list {
  16         struct man_viewer_list *next;
  17         char name[FLEX_ARRAY];
  18 } *man_viewer_list;
  19
  20 static 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
  26 enum help_format {
  27         HELP_FORMAT_NONE,
  28         HELP_FORMAT_MAN,
  29         HELP_FORMAT_INFO,
  30         HELP_FORMAT_WEB
  31 };
  32
  33 static const char *html_path;
  34
  35 static int show_all = 0;
  36 static unsigned int colopts;
  37 static enum help_format help_format = HELP_FORMAT_NONE;
  38 static struct option builtin_help_options[] = {
  39         OPT_BOOLEAN('a', "all", &show_all, "print all available commands"),
  40         OPT_SET_INT('m', "man", &help_format, "show man page", HELP_FORMAT_MAN),
  41         OPT_SET_INT('w', "web", &help_format, "show manual in web browser",
  42                         HELP_FORMAT_WEB),
  43         OPT_SET_INT('i', "info", &help_format, "show info page",
  44                         HELP_FORMAT_INFO),
  45         OPT_END(),
  46 };
  47
  48 static const char * const builtin_help_usage[] = {
  49         "git help [--all] [--man|--web|--info] [command]",
  50         NULL
  51 };
  52
  53 static enum help_format parse_help_format(const char *format)
  54 {
  55         if (!strcmp(format, "man"))
  56                 return HELP_FORMAT_MAN;
  57         if (!strcmp(format, "info"))
  58                 return HELP_FORMAT_INFO;
  59         if (!strcmp(format, "web") || !strcmp(format, "html"))
  60                 return HELP_FORMAT_WEB;
  61         die(_("unrecognized help format '%s'"), format);
  62 }
  63
  64 static const char *get_man_viewer_info(const char *name)
  65 {
  66         struct man_viewer_info_list *viewer;
  67
  68         for (viewer = man_viewer_info_list; viewer; viewer = viewer->next)
  69         {
  70                 if (!strcasecmp(name, viewer->name))
  71                         return viewer->info;
  72         }
  73         return NULL;
  74 }
  75
  76 static int check_emacsclient_version(void)
  77 {
  78         struct strbuf buffer = STRBUF_INIT;
  79         struct child_process ec_process;
  80         const char *argv_ec[] = { "emacsclient", "--version", NULL };
  81         int version;
  82
  83         /* emacsclient prints its version number on stderr */
  84         memset(&ec_process, 0, sizeof(ec_process));
  85         ec_process.argv = argv_ec;
  86         ec_process.err = -1;
  87         ec_process.stdout_to_stderr = 1;
  88         if (start_command(&ec_process))
  89                 return error(_("Failed to start emacsclient."));
  90
  91         strbuf_read(&buffer, ec_process.err, 20);
  92         close(ec_process.err);
  93
  94         /*
  95          * Don't bother checking return value, because "emacsclient --version"
  96          * seems to always exits with code 1.
  97          */
  98         finish_command(&ec_process);
  99
 100         if (prefixcmp(buffer.buf, "emacsclient")) {
 101                 strbuf_release(&buffer);
 102                 return error(_("Failed to parse emacsclient version."));
 103         }
 104
 105         strbuf_remove(&buffer, 0, strlen("emacsclient"));
 106         version = atoi(buffer.buf);
 107
 108         if (version < 22) {
 109                 strbuf_release(&buffer);
 110                 return error(_("emacsclient version '%d' too old (< 22)."),
 111                         version);
 112         }
 113
 114         strbuf_release(&buffer);
 115         return 0;
 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                 struct strbuf man_page = STRBUF_INIT;
 123
 124                 if (!path)
 125                         path = "emacsclient";
 126                 strbuf_addf(&man_page, "(woman \"%s\")", page);
 127                 execlp(path, "emacsclient", "-e", man_page.buf, (char *)NULL);
 128                 warning(_("failed to exec '%s': %s"), path, strerror(errno));
 129         }
 130 }
 131
 132 static void exec_man_konqueror(const char *path, const char *page)
 133 {
 134         const char *display = getenv("DISPLAY");
 135         if (display && *display) {
 136                 struct strbuf man_page = STRBUF_INIT;
 137                 const char *filename = "kfmclient";
 138
 139                 /* It's simpler to launch konqueror using kfmclient. */
 140                 if (path) {
 141                         const char *file = strrchr(path, '/');
 142                         if (file && !strcmp(file + 1, "konqueror")) {
 143                                 char *new = xstrdup(path);
 144                                 char *dest = strrchr(new, '/');
 145
 146                                 /* strlen("konqueror") == strlen("kfmclient") */
 147                                 strcpy(dest + 1, "kfmclient");
 148                                 path = new;
 149                         }
 150                         if (file)
 151                                 filename = file;
 152                 } else
 153                         path = "kfmclient";
 154                 strbuf_addf(&man_page, "man:%s(1)", page);
 155                 execlp(path, filename, "newTab", man_page.buf, (char *)NULL);
 156                 warning(_("failed to exec '%s': %s"), path, strerror(errno));
 157         }
 158 }
 159
 160 static void exec_man_man(const char *path, const char *page)
 161 {
 162         if (!path)
 163                 path = "man";
 164         execlp(path, "man", page, (char *)NULL);
 165         warning(_("failed to exec '%s': %s"), path, strerror(errno));
 166 }
 167
 168 static void exec_man_cmd(const char *cmd, const char *page)
 169 {
 170         struct strbuf shell_cmd = STRBUF_INIT;
 171         strbuf_addf(&shell_cmd, "%s %s", cmd, page);
 172         execl("/bin/sh", "sh", "-c", shell_cmd.buf, (char *)NULL);
 173         warning(_("failed to exec '%s': %s"), cmd, strerror(errno));
 174 }
 175
 176 static void add_man_viewer(const char *name)
 177 {
 178         struct man_viewer_list **p = &man_viewer_list;
 179         size_t len = strlen(name);
 180
 181         while (*p)
 182                 p = &((*p)->next);
 183         *p = xcalloc(1, (sizeof(**p) + len + 1));
 184         strncpy((*p)->name, name, len);
 185 }
 186
 187 static int supported_man_viewer(const char *name, size_t len)
 188 {
 189         return (!strncasecmp("man", name, len) ||
 190                 !strncasecmp("woman", name, len) ||
 191                 !strncasecmp("konqueror", name, len));
 192 }
 193
 194 static void do_add_man_viewer_info(const char *name,
 195                                    size_t len,
 196                                    const char *value)
 197 {
 198         struct man_viewer_info_list *new = xcalloc(1, sizeof(*new) + len + 1);
 199
 200         strncpy(new->name, name, len);
 201         new->info = xstrdup(value);
 202         new->next = man_viewer_info_list;
 203         man_viewer_info_list = new;
 204 }
 205
 206 static int add_man_viewer_path(const char *name,
 207                                size_t len,
 208                                const char *value)
 209 {
 210         if (supported_man_viewer(name, len))
 211                 do_add_man_viewer_info(name, len, value);
 212         else
 213                 warning(_("'%s': path for unsupported man viewer.\n"
 214                           "Please consider using 'man.<tool>.cmd' instead."),
 215                         name);
 216
 217         return 0;
 218 }
 219
 220 static int add_man_viewer_cmd(const char *name,
 221                               size_t len,
 222                               const char *value)
 223 {
 224         if (supported_man_viewer(name, len))
 225                 warning(_("'%s': cmd for supported man viewer.\n"
 226                           "Please consider using 'man.<tool>.path' instead."),
 227                         name);
 228         else
 229                 do_add_man_viewer_info(name, len, value);
 230
 231         return 0;
 232 }
 233
 234 static int add_man_viewer_info(const char *var, const char *value)
 235 {
 236         const char *name = var + 4;
 237         const char *subkey = strrchr(name, '.');
 238
 239         if (!subkey)
 240                 return 0;
 241
 242         if (!strcmp(subkey, ".path")) {
 243                 if (!value)
 244                         return config_error_nonbool(var);
 245                 return add_man_viewer_path(name, subkey - name, value);
 246         }
 247         if (!strcmp(subkey, ".cmd")) {
 248                 if (!value)
 249                         return config_error_nonbool(var);
 250                 return add_man_viewer_cmd(name, subkey - name, value);
 251         }
 252
 253         return 0;
 254 }
 255
 256 static int git_help_config(const char *var, const char *value, void *cb)
 257 {
 258         if (!prefixcmp(var, "column."))
 259                 return git_column_config(var, value, "help", &colopts);
 260         if (!strcmp(var, "help.format")) {
 261                 if (!value)
 262                         return config_error_nonbool(var);
 263                 help_format = parse_help_format(value);
 264                 return 0;
 265         }
 266         if (!strcmp(var, "help.htmlpath")) {
 267                 if (!value)
 268                         return config_error_nonbool(var);
 269                 html_path = xstrdup(value);
 270                 return 0;
 271         }
 272         if (!strcmp(var, "man.viewer")) {
 273                 if (!value)
 274                         return config_error_nonbool(var);
 275                 add_man_viewer(value);
 276                 return 0;
 277         }
 278         if (!prefixcmp(var, "man."))
 279                 return add_man_viewer_info(var, value);
 280
 281         return git_default_config(var, value, cb);
 282 }
 283
 284 static struct cmdnames main_cmds, other_cmds;
 285
 286 void list_common_cmds_help(void)
 287 {
 288         int i, longest = 0;
 289
 290         for (i = 0; i < ARRAY_SIZE(common_cmds); i++) {
 291                 if (longest < strlen(common_cmds[i].name))
 292                         longest = strlen(common_cmds[i].name);
 293         }
 294
 295         puts(_("The most commonly used git commands are:"));
 296         for (i = 0; i < ARRAY_SIZE(common_cmds); i++) {
 297                 printf("   %s   ", common_cmds[i].name);
 298                 mput_char(' ', longest - strlen(common_cmds[i].name));
 299                 puts(_(common_cmds[i].help));
 300         }
 301 }
 302
 303 static int is_git_command(const char *s)
 304 {
 305         return is_in_cmdlist(&main_cmds, s) ||
 306                 is_in_cmdlist(&other_cmds, s);
 307 }
 308
 309 static const char *prepend(const char *prefix, const char *cmd)
 310 {
 311         size_t pre_len = strlen(prefix);
 312         size_t cmd_len = strlen(cmd);
 313         char *p = xmalloc(pre_len + cmd_len + 1);
 314         memcpy(p, prefix, pre_len);
 315         strcpy(p + pre_len, cmd);
 316         return p;
 317 }
 318
 319 static const char *cmd_to_page(const char *git_cmd)
 320 {
 321         if (!git_cmd)
 322                 return "git";
 323         else if (!prefixcmp(git_cmd, "git"))
 324                 return git_cmd;
 325         else if (is_git_command(git_cmd))
 326                 return prepend("git-", git_cmd);
 327         else
 328                 return prepend("git", git_cmd);
 329 }
 330
 331 static void setup_man_path(void)
 332 {
 333         struct strbuf new_path = STRBUF_INIT;
 334         const char *old_path = getenv("MANPATH");
 335
 336         /* We should always put ':' after our path. If there is no
 337          * old_path, the ':' at the end will let 'man' to try
 338          * system-wide paths after ours to find the manual page. If
 339          * there is old_path, we need ':' as delimiter. */
 340         strbuf_addstr(&new_path, system_path(GIT_MAN_PATH));
 341         strbuf_addch(&new_path, ':');
 342         if (old_path)
 343                 strbuf_addstr(&new_path, old_path);
 344
 345         setenv("MANPATH", new_path.buf, 1);
 346
 347         strbuf_release(&new_path);
 348 }
 349
 350 static void exec_viewer(const char *name, const char *page)
 351 {
 352         const char *info = get_man_viewer_info(name);
 353
 354         if (!strcasecmp(name, "man"))
 355                 exec_man_man(info, page);
 356         else if (!strcasecmp(name, "woman"))
 357                 exec_woman_emacs(info, page);
 358         else if (!strcasecmp(name, "konqueror"))
 359                 exec_man_konqueror(info, page);
 360         else if (info)
 361                 exec_man_cmd(info, page);
 362         else
 363                 warning(_("'%s': unknown man viewer."), name);
 364 }
 365
 366 static void show_man_page(const char *git_cmd)
 367 {
 368         struct man_viewer_list *viewer;
 369         const char *page = cmd_to_page(git_cmd);
 370         const char *fallback = getenv("GIT_MAN_VIEWER");
 371
 372         setup_man_path();
 373         for (viewer = man_viewer_list; viewer; viewer = viewer->next)
 374         {
 375                 exec_viewer(viewer->name, page); /* will return when unable */
 376         }
 377         if (fallback)
 378                 exec_viewer(fallback, page);
 379         exec_viewer("man", page);
 380         die(_("no man viewer handled the request"));
 381 }
 382
 383 static void show_info_page(const char *git_cmd)
 384 {
 385         const char *page = cmd_to_page(git_cmd);
 386         setenv("INFOPATH", system_path(GIT_INFO_PATH), 1);
 387         execlp("info", "info", "gitman", page, (char *)NULL);
 388         die(_("no info viewer handled the request"));
 389 }
 390
 391 static void get_html_page_path(struct strbuf *page_path, const char *page)
 392 {
 393         struct stat st;
 394         if (!html_path)
 395                 html_path = system_path(GIT_HTML_PATH);
 396
 397         /* Check that we have a git documentation directory. */
 398         if (stat(mkpath("%s/git.html", html_path), &st)
 399             || !S_ISREG(st.st_mode))
 400                 die(_("'%s': not a documentation directory."), html_path);
 401
 402         strbuf_init(page_path, 0);
 403         strbuf_addf(page_path, "%s/%s.html", html_path, page);
 404 }
 405
 406 /*
 407  * If open_html is not defined in a platform-specific way (see for
 408  * example compat/mingw.h), we use the script web--browse to display
 409  * HTML.
 410  */
 411 #ifndef open_html
 412 static void open_html(const char *path)
 413 {
 414         execl_git_cmd("web--browse", "-c", "help.browser", path, (char *)NULL);
 415 }
 416 #endif
 417
 418 static void show_html_page(const char *git_cmd)
 419 {
 420         const char *page = cmd_to_page(git_cmd);
 421         struct strbuf page_path; /* it leaks but we exec bellow */
 422
 423         get_html_page_path(&page_path, page);
 424
 425         open_html(page_path.buf);
 426 }
 427
 428 int cmd_help(int argc, const char **argv, const char *prefix)
 429 {
 430         int nongit;
 431         const char *alias;
 432         enum help_format parsed_help_format;
 433         load_command_list("git-", &main_cmds, &other_cmds);
 434
 435         argc = parse_options(argc, argv, prefix, builtin_help_options,
 436                         builtin_help_usage, 0);
 437         parsed_help_format = help_format;
 438
 439         if (show_all) {
 440                 git_config(git_help_config, NULL);
 441                 printf(_("usage: %s%s"), _(git_usage_string), "\n\n");
 442                 list_commands(colopts, &main_cmds, &other_cmds);
 443                 printf("%s\n", _(git_more_info_string));
 444                 return 0;
 445         }
 446
 447         if (!argv[0]) {
 448                 printf(_("usage: %s%s"), _(git_usage_string), "\n\n");
 449                 list_common_cmds_help();
 450                 printf("\n%s\n", _(git_more_info_string));
 451                 return 0;
 452         }
 453
 454         setup_git_directory_gently(&nongit);
 455         git_config(git_help_config, NULL);
 456
 457         if (parsed_help_format != HELP_FORMAT_NONE)
 458                 help_format = parsed_help_format;
 459
 460         alias = alias_lookup(argv[0]);
 461         if (alias && !is_git_command(argv[0])) {
 462                 printf_ln(_("`git %s' is aliased to `%s'"), argv[0], alias);
 463                 return 0;
 464         }
 465
 466         switch (help_format) {
 467         case HELP_FORMAT_NONE:
 468         case HELP_FORMAT_MAN:
 469                 show_man_page(argv[0]);
 470                 break;
 471         case HELP_FORMAT_INFO:
 472                 show_info_page(argv[0]);
 473                 break;
 474         case HELP_FORMAT_WEB:
 475                 show_html_page(argv[0]);
 476                 break;
 477         }
 478
 479         return 0;
 480 }