help.c

   1 /*
   2  * builtin-help.c
   3  *
   4  * Builtin help-related commands (help, usage, version)
   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
  13 static struct man_viewer_list {
  14         struct man_viewer_list *next;
  15         char name[FLEX_ARRAY];
  16 } *man_viewer_list;
  17
  18 static struct man_viewer_info_list {
  19         struct man_viewer_info_list *next;
  20         const char *info;
  21         char name[FLEX_ARRAY];
  22 } *man_viewer_info_list;
  23
  24 enum help_format {
  25         HELP_FORMAT_MAN,
  26         HELP_FORMAT_INFO,
  27         HELP_FORMAT_WEB,
  28 };
  29
  30 static int show_all = 0;
  31 static enum help_format help_format = HELP_FORMAT_MAN;
  32 static struct option builtin_help_options[] = {
  33         OPT_BOOLEAN('a', "all", &show_all, "print all available commands"),
  34         OPT_SET_INT('m', "man", &help_format, "show man page", HELP_FORMAT_MAN),
  35         OPT_SET_INT('w', "web", &help_format, "show manual in web browser",
  36                         HELP_FORMAT_WEB),
  37         OPT_SET_INT('i', "info", &help_format, "show info page",
  38                         HELP_FORMAT_INFO),
  39         OPT_END(),
  40 };
  41
  42 static const char * const builtin_help_usage[] = {
  43         "git-help [--all] [--man|--web|--info] [command]",
  44         NULL
  45 };
  46
  47 static enum help_format parse_help_format(const char *format)
  48 {
  49         if (!strcmp(format, "man"))
  50                 return HELP_FORMAT_MAN;
  51         if (!strcmp(format, "info"))
  52                 return HELP_FORMAT_INFO;
  53         if (!strcmp(format, "web") || !strcmp(format, "html"))
  54                 return HELP_FORMAT_WEB;
  55         die("unrecognized help format '%s'", format);
  56 }
  57
  58 static const char *get_man_viewer_info(const char *name)
  59 {
  60         struct man_viewer_info_list *viewer;
  61
  62         for (viewer = man_viewer_info_list; viewer; viewer = viewer->next)
  63         {
  64                 if (!strcasecmp(name, viewer->name))
  65                         return viewer->info;
  66         }
  67         return NULL;
  68 }
  69
  70 static int check_emacsclient_version(void)
  71 {
  72         struct strbuf buffer = STRBUF_INIT;
  73         struct child_process ec_process;
  74         const char *argv_ec[] = { "emacsclient", "--version", NULL };
  75         int version;
  76
  77         /* emacsclient prints its version number on stderr */
  78         memset(&ec_process, 0, sizeof(ec_process));
  79         ec_process.argv = argv_ec;
  80         ec_process.err = -1;
  81         ec_process.stdout_to_stderr = 1;
  82         if (start_command(&ec_process)) {
  83                 fprintf(stderr, "Failed to start emacsclient.\n");
  84                 return -1;
  85         }
  86         strbuf_read(&buffer, ec_process.err, 20);
  87         close(ec_process.err);
  88
  89         /*
  90          * Don't bother checking return value, because "emacsclient --version"
  91          * seems to always exits with code 1.
  92          */
  93         finish_command(&ec_process);
  94
  95         if (prefixcmp(buffer.buf, "emacsclient")) {
  96                 fprintf(stderr, "Failed to parse emacsclient version.\n");
  97                 strbuf_release(&buffer);
  98                 return -1;
  99         }
 100
 101         strbuf_remove(&buffer, 0, strlen("emacsclient"));
 102         version = atoi(buffer.buf);
 103
 104         if (version < 22) {
 105                 fprintf(stderr,
 106                         "emacsclient version '%d' too old (< 22).\n",
 107                         version);
 108                 strbuf_release(&buffer);
 109                 return -1;
 110         }
 111
 112         strbuf_release(&buffer);
 113         return 0;
 114 }
 115
 116 static void exec_woman_emacs(const char* path, const char *page)
 117 {
 118         if (!check_emacsclient_version()) {
 119                 /* This works only with emacsclient version >= 22. */
 120                 struct strbuf man_page = STRBUF_INIT;
 121
 122                 if (!path)
 123                         path = "emacsclient";
 124                 strbuf_addf(&man_page, "(woman \"%s\")", page);
 125                 execlp(path, "emacsclient", "-e", man_page.buf, NULL);
 126                 warning("failed to exec '%s': %s", path, strerror(errno));
 127         }
 128 }
 129
 130 static void exec_man_konqueror(const char* path, const char *page)
 131 {
 132         const char *display = getenv("DISPLAY");
 133         if (display && *display) {
 134                 struct strbuf man_page = STRBUF_INIT;
 135                 const char *filename = "kfmclient";
 136
 137                 /* It's simpler to launch konqueror using kfmclient. */
 138                 if (path) {
 139                         const char *file = strrchr(path, '/');
 140                         if (file && !strcmp(file + 1, "konqueror")) {
 141                                 char *new = xstrdup(path);
 142                                 char *dest = strrchr(new, '/');
 143
 144                                 /* strlen("konqueror") == strlen("kfmclient") */
 145                                 strcpy(dest + 1, "kfmclient");
 146                                 path = new;
 147                         }
 148                         if (file)
 149                                 filename = file;
 150                 } else
 151                         path = "kfmclient";
 152                 strbuf_addf(&man_page, "man:%s(1)", page);
 153                 execlp(path, filename, "newTab", man_page.buf, NULL);
 154                 warning("failed to exec '%s': %s", path, strerror(errno));
 155         }
 156 }
 157
 158 static void exec_man_man(const char* path, const char *page)
 159 {
 160         if (!path)
 161                 path = "man";
 162         execlp(path, "man", page, NULL);
 163         warning("failed to exec '%s': %s", path, strerror(errno));
 164 }
 165
 166 static void exec_man_cmd(const char *cmd, const char *page)
 167 {
 168         struct strbuf shell_cmd = STRBUF_INIT;
 169         strbuf_addf(&shell_cmd, "%s %s", cmd, page);
 170         execl("/bin/sh", "sh", "-c", shell_cmd.buf, NULL);
 171         warning("failed to exec '%s': %s", cmd, strerror(errno));
 172 }
 173
 174 static void add_man_viewer(const char *name)
 175 {
 176         struct man_viewer_list **p = &man_viewer_list;
 177         size_t len = strlen(name);
 178
 179         while (*p)
 180                 p = &((*p)->next);
 181         *p = xcalloc(1, (sizeof(**p) + len + 1));
 182         strncpy((*p)->name, name, len);
 183 }
 184
 185 static int supported_man_viewer(const char *name, size_t len)
 186 {
 187         return (!strncasecmp("man", name, len) ||
 188                 !strncasecmp("woman", name, len) ||
 189                 !strncasecmp("konqueror", name, len));
 190 }
 191
 192 static void do_add_man_viewer_info(const char *name,
 193                                    size_t len,
 194                                    const char *value)
 195 {
 196         struct man_viewer_info_list *new = xcalloc(1, sizeof(*new) + len + 1);
 197
 198         strncpy(new->name, name, len);
 199         new->info = xstrdup(value);
 200         new->next = man_viewer_info_list;
 201         man_viewer_info_list = new;
 202 }
 203
 204 static int add_man_viewer_path(const char *name,
 205                                size_t len,
 206                                const char *value)
 207 {
 208         if (supported_man_viewer(name, len))
 209                 do_add_man_viewer_info(name, len, value);
 210         else
 211                 warning("'%s': path for unsupported man viewer.\n"
 212                         "Please consider using 'man.<tool>.cmd' instead.",
 213                         name);
 214
 215         return 0;
 216 }
 217
 218 static int add_man_viewer_cmd(const char *name,
 219                               size_t len,
 220                               const char *value)
 221 {
 222         if (supported_man_viewer(name, len))
 223                 warning("'%s': cmd for supported man viewer.\n"
 224                         "Please consider using 'man.<tool>.path' instead.",
 225                         name);
 226         else
 227                 do_add_man_viewer_info(name, len, value);
 228
 229         return 0;
 230 }
 231
 232 static int add_man_viewer_info(const char *var, const char *value)
 233 {
 234         const char *name = var + 4;
 235         const char *subkey = strrchr(name, '.');
 236
 237         if (!subkey)
 238                 return error("Config with no key for man viewer: %s", name);
 239
 240         if (!strcmp(subkey, ".path")) {
 241                 if (!value)
 242                         return config_error_nonbool(var);
 243                 return add_man_viewer_path(name, subkey - name, value);
 244         }
 245         if (!strcmp(subkey, ".cmd")) {
 246                 if (!value)
 247                         return config_error_nonbool(var);
 248                 return add_man_viewer_cmd(name, subkey - name, value);
 249         }
 250
 251         warning("'%s': unsupported man viewer sub key.", subkey);
 252         return 0;
 253 }
 254
 255 static int git_help_config(const char *var, const char *value, void *cb)
 256 {
 257         if (!strcmp(var, "help.format")) {
 258                 if (!value)
 259                         return config_error_nonbool(var);
 260                 help_format = parse_help_format(value);
 261                 return 0;
 262         }
 263         if (!strcmp(var, "man.viewer")) {
 264                 if (!value)
 265                         return config_error_nonbool(var);
 266                 add_man_viewer(value);
 267                 return 0;
 268         }
 269         if (!prefixcmp(var, "man."))
 270                 return add_man_viewer_info(var, value);
 271
 272         return git_default_config(var, value, cb);
 273 }
 274
 275 /* most GUI terminals set COLUMNS (although some don't export it) */
 276 static int term_columns(void)
 277 {
 278         char *col_string = getenv("COLUMNS");
 279         int n_cols;
 280
 281         if (col_string && (n_cols = atoi(col_string)) > 0)
 282                 return n_cols;
 283
 284 #ifdef TIOCGWINSZ
 285         {
 286                 struct winsize ws;
 287                 if (!ioctl(1, TIOCGWINSZ, &ws)) {
 288                         if (ws.ws_col)
 289                                 return ws.ws_col;
 290                 }
 291         }
 292 #endif
 293
 294         return 80;
 295 }
 296
 297 static inline void mput_char(char c, unsigned int num)
 298 {
 299         while(num--)
 300                 putchar(c);
 301 }
 302
 303 static struct cmdnames {
 304         int alloc;
 305         int cnt;
 306         struct cmdname {
 307                 size_t len;
 308                 char name[1];
 309         } **names;
 310 } main_cmds, other_cmds;
 311
 312 static void add_cmdname(struct cmdnames *cmds, const char *name, int len)
 313 {
 314         struct cmdname *ent = xmalloc(sizeof(*ent) + len);
 315
 316         ent->len = len;
 317         memcpy(ent->name, name, len);
 318         ent->name[len] = 0;
 319
 320         ALLOC_GROW(cmds->names, cmds->cnt + 1, cmds->alloc);
 321         cmds->names[cmds->cnt++] = ent;
 322 }
 323
 324 static int cmdname_compare(const void *a_, const void *b_)
 325 {
 326         struct cmdname *a = *(struct cmdname **)a_;
 327         struct cmdname *b = *(struct cmdname **)b_;
 328         return strcmp(a->name, b->name);
 329 }
 330
 331 static void uniq(struct cmdnames *cmds)
 332 {
 333         int i, j;
 334
 335         if (!cmds->cnt)
 336                 return;
 337
 338         for (i = j = 1; i < cmds->cnt; i++)
 339                 if (strcmp(cmds->names[i]->name, cmds->names[i-1]->name))
 340                         cmds->names[j++] = cmds->names[i];
 341
 342         cmds->cnt = j;
 343 }
 344
 345 static void exclude_cmds(struct cmdnames *cmds, struct cmdnames *excludes)
 346 {
 347         int ci, cj, ei;
 348         int cmp;
 349
 350         ci = cj = ei = 0;
 351         while (ci < cmds->cnt && ei < excludes->cnt) {
 352                 cmp = strcmp(cmds->names[ci]->name, excludes->names[ei]->name);
 353                 if (cmp < 0)
 354                         cmds->names[cj++] = cmds->names[ci++];
 355                 else if (cmp == 0)
 356                         ci++, ei++;
 357                 else if (cmp > 0)
 358                         ei++;
 359         }
 360
 361         while (ci < cmds->cnt)
 362                 cmds->names[cj++] = cmds->names[ci++];
 363
 364         cmds->cnt = cj;
 365 }
 366
 367 static void pretty_print_string_list(struct cmdnames *cmds, int longest)
 368 {
 369         int cols = 1, rows;
 370         int space = longest + 1; /* min 1 SP between words */
 371         int max_cols = term_columns() - 1; /* don't print *on* the edge */
 372         int i, j;
 373
 374         if (space < max_cols)
 375                 cols = max_cols / space;
 376         rows = (cmds->cnt + cols - 1) / cols;
 377
 378         for (i = 0; i < rows; i++) {
 379                 printf("  ");
 380
 381                 for (j = 0; j < cols; j++) {
 382                         int n = j * rows + i;
 383                         int size = space;
 384                         if (n >= cmds->cnt)
 385                                 break;
 386                         if (j == cols-1 || n + rows >= cmds->cnt)
 387                                 size = 1;
 388                         printf("%-*s", size, cmds->names[n]->name);
 389                 }
 390                 putchar('\n');
 391         }
 392 }
 393
 394 static int is_executable(const char *name)
 395 {
 396         struct stat st;
 397
 398         if (stat(name, &st) || /* stat, not lstat */
 399             !S_ISREG(st.st_mode))
 400                 return 0;
 401
 402 #ifdef __MINGW32__
 403         /* cannot trust the executable bit, peek into the file instead */
 404         char buf[3] = { 0 };
 405         int n;
 406         int fd = open(name, O_RDONLY);
 407         st.st_mode &= ~S_IXUSR;
 408         if (fd >= 0) {
 409                 n = read(fd, buf, 2);
 410                 if (n == 2)
 411                         /* DOS executables start with "MZ" */
 412                         if (!strcmp(buf, "#!") || !strcmp(buf, "MZ"))
 413                                 st.st_mode |= S_IXUSR;
 414                 close(fd);
 415         }
 416 #endif
 417         return st.st_mode & S_IXUSR;
 418 }
 419
 420 static unsigned int list_commands_in_dir(struct cmdnames *cmds,
 421                                          const char *path)
 422 {
 423         unsigned int longest = 0;
 424         const char *prefix = "git-";
 425         int prefix_len = strlen(prefix);
 426         DIR *dir = opendir(path);
 427         struct dirent *de;
 428
 429         if (!dir || chdir(path))
 430                 return 0;
 431
 432         while ((de = readdir(dir)) != NULL) {
 433                 int entlen;
 434
 435                 if (prefixcmp(de->d_name, prefix))
 436                         continue;
 437
 438                 if (!is_executable(de->d_name))
 439                         continue;
 440
 441                 entlen = strlen(de->d_name) - prefix_len;
 442                 if (has_extension(de->d_name, ".exe"))
 443                         entlen -= 4;
 444
 445                 if (longest < entlen)
 446                         longest = entlen;
 447
 448                 add_cmdname(cmds, de->d_name + prefix_len, entlen);
 449         }
 450         closedir(dir);
 451
 452         return longest;
 453 }
 454
 455 static unsigned int load_command_list(void)
 456 {
 457         unsigned int longest = 0;
 458         unsigned int len;
 459         const char *env_path = getenv("PATH");
 460         char *paths, *path, *colon;
 461         const char *exec_path = git_exec_path();
 462
 463         if (exec_path)
 464                 longest = list_commands_in_dir(&main_cmds, exec_path);
 465
 466         if (!env_path) {
 467                 fprintf(stderr, "PATH not set\n");
 468                 exit(1);
 469         }
 470
 471         path = paths = xstrdup(env_path);
 472         while (1) {
 473                 if ((colon = strchr(path, PATH_SEP)))
 474                         *colon = 0;
 475
 476                 len = list_commands_in_dir(&other_cmds, path);
 477                 if (len > longest)
 478                         longest = len;
 479
 480                 if (!colon)
 481                         break;
 482                 path = colon + 1;
 483         }
 484         free(paths);
 485
 486         qsort(main_cmds.names, main_cmds.cnt,
 487               sizeof(*main_cmds.names), cmdname_compare);
 488         uniq(&main_cmds);
 489
 490         qsort(other_cmds.names, other_cmds.cnt,
 491               sizeof(*other_cmds.names), cmdname_compare);
 492         uniq(&other_cmds);
 493         exclude_cmds(&other_cmds, &main_cmds);
 494
 495         return longest;
 496 }
 497
 498 static void list_commands(void)
 499 {
 500         unsigned int longest = load_command_list();
 501         const char *exec_path = git_exec_path();
 502
 503         if (main_cmds.cnt) {
 504                 printf("available git commands in '%s'\n", exec_path);
 505                 printf("----------------------------");
 506                 mput_char('-', strlen(exec_path));
 507                 putchar('\n');
 508                 pretty_print_string_list(&main_cmds, longest);
 509                 putchar('\n');
 510         }
 511
 512         if (other_cmds.cnt) {
 513                 printf("git commands available from elsewhere on your $PATH\n");
 514                 printf("---------------------------------------------------\n");
 515                 pretty_print_string_list(&other_cmds, longest);
 516                 putchar('\n');
 517         }
 518 }
 519
 520 void list_common_cmds_help(void)
 521 {
 522         int i, longest = 0;
 523
 524         for (i = 0; i < ARRAY_SIZE(common_cmds); i++) {
 525                 if (longest < strlen(common_cmds[i].name))
 526                         longest = strlen(common_cmds[i].name);
 527         }
 528
 529         puts("The most commonly used git commands are:");
 530         for (i = 0; i < ARRAY_SIZE(common_cmds); i++) {
 531                 printf("   %s   ", common_cmds[i].name);
 532                 mput_char(' ', longest - strlen(common_cmds[i].name));
 533                 puts(common_cmds[i].help);
 534         }
 535 }
 536
 537 static int is_in_cmdlist(struct cmdnames *c, const char *s)
 538 {
 539         int i;
 540         for (i = 0; i < c->cnt; i++)
 541                 if (!strcmp(s, c->names[i]->name))
 542                         return 1;
 543         return 0;
 544 }
 545
 546 static int is_git_command(const char *s)
 547 {
 548         load_command_list();
 549         return is_in_cmdlist(&main_cmds, s) ||
 550                 is_in_cmdlist(&other_cmds, s);
 551 }
 552
 553 static const char *prepend(const char *prefix, const char *cmd)
 554 {
 555         size_t pre_len = strlen(prefix);
 556         size_t cmd_len = strlen(cmd);
 557         char *p = xmalloc(pre_len + cmd_len + 1);
 558         memcpy(p, prefix, pre_len);
 559         strcpy(p + pre_len, cmd);
 560         return p;
 561 }
 562
 563 static const char *cmd_to_page(const char *git_cmd)
 564 {
 565         if (!git_cmd)
 566                 return "git";
 567         else if (!prefixcmp(git_cmd, "git"))
 568                 return git_cmd;
 569         else if (is_git_command(git_cmd))
 570                 return prepend("git-", git_cmd);
 571         else
 572                 return prepend("git", git_cmd);
 573 }
 574
 575 static void setup_man_path(void)
 576 {
 577         struct strbuf new_path;
 578         const char *old_path = getenv("MANPATH");
 579
 580         strbuf_init(&new_path, 0);
 581
 582         /* We should always put ':' after our path. If there is no
 583          * old_path, the ':' at the end will let 'man' to try
 584          * system-wide paths after ours to find the manual page. If
 585          * there is old_path, we need ':' as delimiter. */
 586         strbuf_addstr(&new_path, GIT_MAN_PATH);
 587         strbuf_addch(&new_path, ':');
 588         if (old_path)
 589                 strbuf_addstr(&new_path, old_path);
 590
 591         setenv("MANPATH", new_path.buf, 1);
 592
 593         strbuf_release(&new_path);
 594 }
 595
 596 static void exec_viewer(const char *name, const char *page)
 597 {
 598         const char *info = get_man_viewer_info(name);
 599
 600         if (!strcasecmp(name, "man"))
 601                 exec_man_man(info, page);
 602         else if (!strcasecmp(name, "woman"))
 603                 exec_woman_emacs(info, page);
 604         else if (!strcasecmp(name, "konqueror"))
 605                 exec_man_konqueror(info, page);
 606         else if (info)
 607                 exec_man_cmd(info, page);
 608         else
 609                 warning("'%s': unknown man viewer.", name);
 610 }
 611
 612 static void show_man_page(const char *git_cmd)
 613 {
 614         struct man_viewer_list *viewer;
 615         const char *page = cmd_to_page(git_cmd);
 616
 617         setup_man_path();
 618         for (viewer = man_viewer_list; viewer; viewer = viewer->next)
 619         {
 620                 exec_viewer(viewer->name, page); /* will return when unable */
 621         }
 622         exec_viewer("man", page);
 623         die("no man viewer handled the request");
 624 }
 625
 626 static void show_info_page(const char *git_cmd)
 627 {
 628         const char *page = cmd_to_page(git_cmd);
 629         setenv("INFOPATH", GIT_INFO_PATH, 1);
 630         execlp("info", "info", "gitman", page, NULL);
 631 }
 632
 633 static void get_html_page_path(struct strbuf *page_path, const char *page)
 634 {
 635         struct stat st;
 636         const char *html_path = system_path(GIT_HTML_PATH);
 637
 638         /* Check that we have a git documentation directory. */
 639         if (stat(mkpath("%s/git.html", html_path), &st)
 640             || !S_ISREG(st.st_mode))
 641                 die("'%s': not a documentation directory.", html_path);
 642
 643         strbuf_init(page_path, 0);
 644         strbuf_addf(page_path, "%s/%s.html", html_path, page);
 645 }
 646
 647 /*
 648  * If open_html is not defined in a platform-specific way (see for
 649  * example compat/mingw.h), we use the script web--browse to display
 650  * HTML.
 651  */
 652 #ifndef open_html
 653 void open_html(const char *path)
 654 {
 655         execl_git_cmd("web--browse", "-c", "help.browser", path, NULL);
 656 }
 657 #endif
 658
 659 static void show_html_page(const char *git_cmd)
 660 {
 661         const char *page = cmd_to_page(git_cmd);
 662         struct strbuf page_path; /* it leaks but we exec bellow */
 663
 664         get_html_page_path(&page_path, page);
 665
 666         open_html(page_path.buf);
 667 }
 668
 669 void help_unknown_cmd(const char *cmd)
 670 {
 671         fprintf(stderr, "git: '%s' is not a git-command. See 'git --help'.\n", cmd);
 672         exit(1);
 673 }
 674
 675 int cmd_version(int argc, const char **argv, const char *prefix)
 676 {
 677         printf("git version %s\n", git_version_string);
 678         return 0;
 679 }
 680
 681 int cmd_help(int argc, const char **argv, const char *prefix)
 682 {
 683         int nongit;
 684         const char *alias;
 685
 686         setup_git_directory_gently(&nongit);
 687         git_config(git_help_config, NULL);
 688
 689         argc = parse_options(argc, argv, builtin_help_options,
 690                         builtin_help_usage, 0);
 691
 692         if (show_all) {
 693                 printf("usage: %s\n\n", git_usage_string);
 694                 list_commands();
 695                 printf("%s\n", git_more_info_string);
 696                 return 0;
 697         }
 698
 699         if (!argv[0]) {
 700                 printf("usage: %s\n\n", git_usage_string);
 701                 list_common_cmds_help();
 702                 printf("\n%s\n", git_more_info_string);
 703                 return 0;
 704         }
 705
 706         alias = alias_lookup(argv[0]);
 707         if (alias && !is_git_command(argv[0])) {
 708                 printf("`git %s' is aliased to `%s'\n", argv[0], alias);
 709                 return 0;
 710         }
 711
 712         switch (help_format) {
 713         case HELP_FORMAT_MAN:
 714                 show_man_page(argv[0]);
 715                 break;
 716         case HELP_FORMAT_INFO:
 717                 show_info_page(argv[0]);
 718                 break;
 719         case HELP_FORMAT_WEB:
 720                 show_html_page(argv[0]);
 721                 break;
 722         }
 723
 724         return 0;
 725 }