git.c

   1 #include "builtin.h"
   2 #include "exec_cmd.h"
   3 #include "help.h"
   4 #include "run-command.h"
   5
   6 const char git_usage_string[] =
   7         "git [--version] [--help] [-C <path>] [-c name=value]\n"
   8         "           [--exec-path[=<path>]] [--html-path] [--man-path] [--info-path]\n"
   9         "           [-p | --paginate | --no-pager] [--no-replace-objects] [--bare]\n"
  10         "           [--git-dir=<path>] [--work-tree=<path>] [--namespace=<name>]\n"
  11         "           <command> [<args>]";
  12
  13 const char git_more_info_string[] =
  14         N_("'git help -a' and 'git help -g' list available subcommands and some\n"
  15            "concept guides. See 'git help <command>' or 'git help <concept>'\n"
  16            "to read about a specific subcommand or concept.");
  17
  18 static int use_pager = -1;
  19
  20 static void list_builtins(void);
  21
  22 static void commit_pager_choice(void) {
  23         switch (use_pager) {
  24         case 0:
  25                 setenv("GIT_PAGER", "cat", 1);
  26                 break;
  27         case 1:
  28                 setup_pager();
  29                 break;
  30         default:
  31                 break;
  32         }
  33 }
  34
  35 static int handle_options(const char ***argv, int *argc, int *envchanged)
  36 {
  37         const char **orig_argv = *argv;
  38
  39         while (*argc > 0) {
  40                 const char *cmd = (*argv)[0];
  41                 if (cmd[0] != '-')
  42                         break;
  43
  44                 /*
  45                  * For legacy reasons, the "version" and "help"
  46                  * commands can be written with "--" prepended
  47                  * to make them look like flags.
  48                  */
  49                 if (!strcmp(cmd, "--help") || !strcmp(cmd, "--version"))
  50                         break;
  51
  52                 /*
  53                  * Check remaining flags.
  54                  */
  55                 if (skip_prefix(cmd, "--exec-path", &cmd)) {
  56                         if (*cmd == '=')
  57                                 git_set_argv_exec_path(cmd + 1);
  58                         else {
  59                                 puts(git_exec_path());
  60                                 exit(0);
  61                         }
  62                 } else if (!strcmp(cmd, "--html-path")) {
  63                         puts(system_path(GIT_HTML_PATH));
  64                         exit(0);
  65                 } else if (!strcmp(cmd, "--man-path")) {
  66                         puts(system_path(GIT_MAN_PATH));
  67                         exit(0);
  68                 } else if (!strcmp(cmd, "--info-path")) {
  69                         puts(system_path(GIT_INFO_PATH));
  70                         exit(0);
  71                 } else if (!strcmp(cmd, "-p") || !strcmp(cmd, "--paginate")) {
  72                         use_pager = 1;
  73                 } else if (!strcmp(cmd, "--no-pager")) {
  74                         use_pager = 0;
  75                         if (envchanged)
  76                                 *envchanged = 1;
  77                 } else if (!strcmp(cmd, "--no-replace-objects")) {
  78                         check_replace_refs = 0;
  79                         setenv(NO_REPLACE_OBJECTS_ENVIRONMENT, "1", 1);
  80                         if (envchanged)
  81                                 *envchanged = 1;
  82                 } else if (!strcmp(cmd, "--git-dir")) {
  83                         if (*argc < 2) {
  84                                 fprintf(stderr, "No directory given for --git-dir.\n" );
  85                                 usage(git_usage_string);
  86                         }
  87                         setenv(GIT_DIR_ENVIRONMENT, (*argv)[1], 1);
  88                         if (envchanged)
  89                                 *envchanged = 1;
  90                         (*argv)++;
  91                         (*argc)--;
  92                 } else if (skip_prefix(cmd, "--git-dir=", &cmd)) {
  93                         setenv(GIT_DIR_ENVIRONMENT, cmd, 1);
  94                         if (envchanged)
  95                                 *envchanged = 1;
  96                 } else if (!strcmp(cmd, "--namespace")) {
  97                         if (*argc < 2) {
  98                                 fprintf(stderr, "No namespace given for --namespace.\n" );
  99                                 usage(git_usage_string);
 100                         }
 101                         setenv(GIT_NAMESPACE_ENVIRONMENT, (*argv)[1], 1);
 102                         if (envchanged)
 103                                 *envchanged = 1;
 104                         (*argv)++;
 105                         (*argc)--;
 106                 } else if (skip_prefix(cmd, "--namespace=", &cmd)) {
 107                         setenv(GIT_NAMESPACE_ENVIRONMENT, cmd, 1);
 108                         if (envchanged)
 109                                 *envchanged = 1;
 110                 } else if (!strcmp(cmd, "--work-tree")) {
 111                         if (*argc < 2) {
 112                                 fprintf(stderr, "No directory given for --work-tree.\n" );
 113                                 usage(git_usage_string);
 114                         }
 115                         setenv(GIT_WORK_TREE_ENVIRONMENT, (*argv)[1], 1);
 116                         if (envchanged)
 117                                 *envchanged = 1;
 118                         (*argv)++;
 119                         (*argc)--;
 120                 } else if (skip_prefix(cmd, "--work-tree=", &cmd)) {
 121                         setenv(GIT_WORK_TREE_ENVIRONMENT, cmd, 1);
 122                         if (envchanged)
 123                                 *envchanged = 1;
 124                 } else if (!strcmp(cmd, "--super-prefix")) {
 125                         if (*argc < 2) {
 126                                 fprintf(stderr, "No prefix given for --super-prefix.\n" );
 127                                 usage(git_usage_string);
 128                         }
 129                         setenv(GIT_SUPER_PREFIX_ENVIRONMENT, (*argv)[1], 1);
 130                         if (envchanged)
 131                                 *envchanged = 1;
 132                         (*argv)++;
 133                         (*argc)--;
 134                 } else if (skip_prefix(cmd, "--super-prefix=", &cmd)) {
 135                         setenv(GIT_SUPER_PREFIX_ENVIRONMENT, cmd, 1);
 136                         if (envchanged)
 137                                 *envchanged = 1;
 138                 } else if (!strcmp(cmd, "--bare")) {
 139                         char *cwd = xgetcwd();
 140                         is_bare_repository_cfg = 1;
 141                         setenv(GIT_DIR_ENVIRONMENT, cwd, 0);
 142                         free(cwd);
 143                         setenv(GIT_IMPLICIT_WORK_TREE_ENVIRONMENT, "0", 1);
 144                         if (envchanged)
 145                                 *envchanged = 1;
 146                 } else if (!strcmp(cmd, "-c")) {
 147                         if (*argc < 2) {
 148                                 fprintf(stderr, "-c expects a configuration string\n" );
 149                                 usage(git_usage_string);
 150                         }
 151                         git_config_push_parameter((*argv)[1]);
 152                         (*argv)++;
 153                         (*argc)--;
 154                 } else if (!strcmp(cmd, "--literal-pathspecs")) {
 155                         setenv(GIT_LITERAL_PATHSPECS_ENVIRONMENT, "1", 1);
 156                         if (envchanged)
 157                                 *envchanged = 1;
 158                 } else if (!strcmp(cmd, "--no-literal-pathspecs")) {
 159                         setenv(GIT_LITERAL_PATHSPECS_ENVIRONMENT, "0", 1);
 160                         if (envchanged)
 161                                 *envchanged = 1;
 162                 } else if (!strcmp(cmd, "--glob-pathspecs")) {
 163                         setenv(GIT_GLOB_PATHSPECS_ENVIRONMENT, "1", 1);
 164                         if (envchanged)
 165                                 *envchanged = 1;
 166                 } else if (!strcmp(cmd, "--noglob-pathspecs")) {
 167                         setenv(GIT_NOGLOB_PATHSPECS_ENVIRONMENT, "1", 1);
 168                         if (envchanged)
 169                                 *envchanged = 1;
 170                 } else if (!strcmp(cmd, "--icase-pathspecs")) {
 171                         setenv(GIT_ICASE_PATHSPECS_ENVIRONMENT, "1", 1);
 172                         if (envchanged)
 173                                 *envchanged = 1;
 174                 } else if (!strcmp(cmd, "--shallow-file")) {
 175                         (*argv)++;
 176                         (*argc)--;
 177                         set_alternate_shallow_file((*argv)[0], 1);
 178                         if (envchanged)
 179                                 *envchanged = 1;
 180                 } else if (!strcmp(cmd, "-C")) {
 181                         if (*argc < 2) {
 182                                 fprintf(stderr, "No directory given for -C.\n" );
 183                                 usage(git_usage_string);
 184                         }
 185                         if ((*argv)[1][0]) {
 186                                 if (chdir((*argv)[1]))
 187                                         die_errno("Cannot change to '%s'", (*argv)[1]);
 188                                 if (envchanged)
 189                                         *envchanged = 1;
 190                         }
 191                         (*argv)++;
 192                         (*argc)--;
 193                 } else if (!strcmp(cmd, "--list-builtins")) {
 194                         list_builtins();
 195                         exit(0);
 196                 } else {
 197                         fprintf(stderr, "Unknown option: %s\n", cmd);
 198                         usage(git_usage_string);
 199                 }
 200
 201                 (*argv)++;
 202                 (*argc)--;
 203         }
 204         return (*argv) - orig_argv;
 205 }
 206
 207 static int handle_alias(int *argcp, const char ***argv)
 208 {
 209         int envchanged = 0, ret = 0, saved_errno = errno;
 210         int count, option_count;
 211         const char **new_argv;
 212         const char *alias_command;
 213         char *alias_string;
 214
 215         alias_command = (*argv)[0];
 216         alias_string = alias_lookup(alias_command);
 217         if (alias_string) {
 218                 if (alias_string[0] == '!') {
 219                         struct child_process child = CHILD_PROCESS_INIT;
 220                         int nongit_ok;
 221
 222                         /* Aliases expect GIT_PREFIX, GIT_DIR etc to be set */
 223                         setup_git_directory_gently(&nongit_ok);
 224
 225                         commit_pager_choice();
 226
 227                         child.use_shell = 1;
 228                         argv_array_push(&child.args, alias_string + 1);
 229                         argv_array_pushv(&child.args, (*argv) + 1);
 230
 231                         ret = run_command(&child);
 232                         if (ret >= 0)   /* normal exit */
 233                                 exit(ret);
 234
 235                         die_errno("While expanding alias '%s': '%s'",
 236                             alias_command, alias_string + 1);
 237                 }
 238                 count = split_cmdline(alias_string, &new_argv);
 239                 if (count < 0)
 240                         die("Bad alias.%s string: %s", alias_command,
 241                             split_cmdline_strerror(count));
 242                 option_count = handle_options(&new_argv, &count, &envchanged);
 243                 if (envchanged)
 244                         die("alias '%s' changes environment variables\n"
 245                                  "You can use '!git' in the alias to do this.",
 246                                  alias_command);
 247                 memmove(new_argv - option_count, new_argv,
 248                                 count * sizeof(char *));
 249                 new_argv -= option_count;
 250
 251                 if (count < 1)
 252                         die("empty alias for %s", alias_command);
 253
 254                 if (!strcmp(alias_command, new_argv[0]))
 255                         die("recursive alias: %s", alias_command);
 256
 257                 trace_argv_printf(new_argv,
 258                                   "trace: alias expansion: %s =>",
 259                                   alias_command);
 260
 261                 REALLOC_ARRAY(new_argv, count + *argcp);
 262                 /* insert after command name */
 263                 memcpy(new_argv + count, *argv + 1, sizeof(char *) * *argcp);
 264
 265                 *argv = new_argv;
 266                 *argcp += count - 1;
 267
 268                 ret = 1;
 269         }
 270
 271         errno = saved_errno;
 272
 273         return ret;
 274 }
 275
 276 #define RUN_SETUP               (1<<0)
 277 #define RUN_SETUP_GENTLY        (1<<1)
 278 #define USE_PAGER               (1<<2)
 279 /*
 280  * require working tree to be present -- anything uses this needs
 281  * RUN_SETUP for reading from the configuration file.
 282  */
 283 #define NEED_WORK_TREE          (1<<3)
 284 #define SUPPORT_SUPER_PREFIX    (1<<4)
 285
 286 struct cmd_struct {
 287         const char *cmd;
 288         int (*fn)(int, const char **, const char *);
 289         int option;
 290 };
 291
 292 static int run_builtin(struct cmd_struct *p, int argc, const char **argv)
 293 {
 294         int status, help;
 295         struct stat st;
 296         const char *prefix;
 297
 298         prefix = NULL;
 299         help = argc == 2 && !strcmp(argv[1], "-h");
 300         if (!help) {
 301                 if (p->option & RUN_SETUP)
 302                         prefix = setup_git_directory();
 303                 else if (p->option & RUN_SETUP_GENTLY) {
 304                         int nongit_ok;
 305                         prefix = setup_git_directory_gently(&nongit_ok);
 306                 }
 307
 308                 if (use_pager == -1 && p->option & (RUN_SETUP | RUN_SETUP_GENTLY))
 309                         use_pager = check_pager_config(p->cmd);
 310                 if (use_pager == -1 && p->option & USE_PAGER)
 311                         use_pager = 1;
 312
 313                 if ((p->option & (RUN_SETUP | RUN_SETUP_GENTLY)) &&
 314                     startup_info->have_repository) /* get_git_dir() may set up repo, avoid that */
 315                         trace_repo_setup(prefix);
 316         }
 317         commit_pager_choice();
 318
 319         if (!help && get_super_prefix()) {
 320                 if (!(p->option & SUPPORT_SUPER_PREFIX))
 321                         die("%s doesn't support --super-prefix", p->cmd);
 322         }
 323
 324         if (!help && p->option & NEED_WORK_TREE)
 325                 setup_work_tree();
 326
 327         trace_argv_printf(argv, "trace: built-in: git");
 328
 329         status = p->fn(argc, argv, prefix);
 330         if (status)
 331                 return status;
 332
 333         /* Somebody closed stdout? */
 334         if (fstat(fileno(stdout), &st))
 335                 return 0;
 336         /* Ignore write errors for pipes and sockets.. */
 337         if (S_ISFIFO(st.st_mode) || S_ISSOCK(st.st_mode))
 338                 return 0;
 339
 340         /* Check for ENOSPC and EIO errors.. */
 341         if (fflush(stdout))
 342                 die_errno("write failure on standard output");
 343         if (ferror(stdout))
 344                 die("unknown write failure on standard output");
 345         if (fclose(stdout))
 346                 die_errno("close failed on standard output");
 347         return 0;
 348 }
 349
 350 static struct cmd_struct commands[] = {
 351         { "add", cmd_add, RUN_SETUP | NEED_WORK_TREE },
 352         { "am", cmd_am, RUN_SETUP | NEED_WORK_TREE },
 353         { "annotate", cmd_annotate, RUN_SETUP },
 354         { "apply", cmd_apply, RUN_SETUP_GENTLY },
 355         { "archive", cmd_archive, RUN_SETUP_GENTLY },
 356         { "bisect--helper", cmd_bisect__helper, RUN_SETUP },
 357         { "blame", cmd_blame, RUN_SETUP },
 358         { "branch", cmd_branch, RUN_SETUP },
 359         { "bundle", cmd_bundle, RUN_SETUP_GENTLY },
 360         { "cat-file", cmd_cat_file, RUN_SETUP },
 361         { "check-attr", cmd_check_attr, RUN_SETUP },
 362         { "check-ignore", cmd_check_ignore, RUN_SETUP | NEED_WORK_TREE },
 363         { "check-mailmap", cmd_check_mailmap, RUN_SETUP },
 364         { "check-ref-format", cmd_check_ref_format },
 365         { "checkout", cmd_checkout, RUN_SETUP | NEED_WORK_TREE },
 366         { "checkout-index", cmd_checkout_index,
 367                 RUN_SETUP | NEED_WORK_TREE},
 368         { "cherry", cmd_cherry, RUN_SETUP },
 369         { "cherry-pick", cmd_cherry_pick, RUN_SETUP | NEED_WORK_TREE },
 370         { "clean", cmd_clean, RUN_SETUP | NEED_WORK_TREE },
 371         { "clone", cmd_clone },
 372         { "column", cmd_column, RUN_SETUP_GENTLY },
 373         { "commit", cmd_commit, RUN_SETUP | NEED_WORK_TREE },
 374         { "commit-tree", cmd_commit_tree, RUN_SETUP },
 375         { "config", cmd_config, RUN_SETUP_GENTLY },
 376         { "count-objects", cmd_count_objects, RUN_SETUP },
 377         { "credential", cmd_credential, RUN_SETUP_GENTLY },
 378         { "describe", cmd_describe, RUN_SETUP },
 379         { "diff", cmd_diff },
 380         { "diff-files", cmd_diff_files, RUN_SETUP | NEED_WORK_TREE },
 381         { "diff-index", cmd_diff_index, RUN_SETUP },
 382         { "diff-tree", cmd_diff_tree, RUN_SETUP },
 383         { "difftool", cmd_difftool, RUN_SETUP | NEED_WORK_TREE },
 384         { "fast-export", cmd_fast_export, RUN_SETUP },
 385         { "fetch", cmd_fetch, RUN_SETUP },
 386         { "fetch-pack", cmd_fetch_pack, RUN_SETUP },
 387         { "fmt-merge-msg", cmd_fmt_merge_msg, RUN_SETUP },
 388         { "for-each-ref", cmd_for_each_ref, RUN_SETUP },
 389         { "format-patch", cmd_format_patch, RUN_SETUP },
 390         { "fsck", cmd_fsck, RUN_SETUP },
 391         { "fsck-objects", cmd_fsck, RUN_SETUP },
 392         { "gc", cmd_gc, RUN_SETUP },
 393         { "get-tar-commit-id", cmd_get_tar_commit_id },
 394         { "grep", cmd_grep, RUN_SETUP_GENTLY | SUPPORT_SUPER_PREFIX },
 395         { "hash-object", cmd_hash_object },
 396         { "help", cmd_help },
 397         { "index-pack", cmd_index_pack, RUN_SETUP_GENTLY },
 398         { "init", cmd_init_db },
 399         { "init-db", cmd_init_db },
 400         { "interpret-trailers", cmd_interpret_trailers, RUN_SETUP_GENTLY },
 401         { "log", cmd_log, RUN_SETUP },
 402         { "ls-files", cmd_ls_files, RUN_SETUP | SUPPORT_SUPER_PREFIX },
 403         { "ls-remote", cmd_ls_remote, RUN_SETUP_GENTLY },
 404         { "ls-tree", cmd_ls_tree, RUN_SETUP },
 405         { "mailinfo", cmd_mailinfo, RUN_SETUP_GENTLY },
 406         { "mailsplit", cmd_mailsplit },
 407         { "merge", cmd_merge, RUN_SETUP | NEED_WORK_TREE },
 408         { "merge-base", cmd_merge_base, RUN_SETUP },
 409         { "merge-file", cmd_merge_file, RUN_SETUP_GENTLY },
 410         { "merge-index", cmd_merge_index, RUN_SETUP },
 411         { "merge-ours", cmd_merge_ours, RUN_SETUP },
 412         { "merge-recursive", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE },
 413         { "merge-recursive-ours", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE },
 414         { "merge-recursive-theirs", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE },
 415         { "merge-subtree", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE },
 416         { "merge-tree", cmd_merge_tree, RUN_SETUP },
 417         { "mktag", cmd_mktag, RUN_SETUP },
 418         { "mktree", cmd_mktree, RUN_SETUP },
 419         { "mv", cmd_mv, RUN_SETUP | NEED_WORK_TREE },
 420         { "name-rev", cmd_name_rev, RUN_SETUP },
 421         { "notes", cmd_notes, RUN_SETUP },
 422         { "pack-objects", cmd_pack_objects, RUN_SETUP },
 423         { "pack-redundant", cmd_pack_redundant, RUN_SETUP },
 424         { "pack-refs", cmd_pack_refs, RUN_SETUP },
 425         { "patch-id", cmd_patch_id, RUN_SETUP_GENTLY },
 426         { "pickaxe", cmd_blame, RUN_SETUP },
 427         { "prune", cmd_prune, RUN_SETUP },
 428         { "prune-packed", cmd_prune_packed, RUN_SETUP },
 429         { "pull", cmd_pull, RUN_SETUP | NEED_WORK_TREE },
 430         { "push", cmd_push, RUN_SETUP },
 431         { "read-tree", cmd_read_tree, RUN_SETUP | SUPPORT_SUPER_PREFIX},
 432         { "rebase--helper", cmd_rebase__helper, RUN_SETUP | NEED_WORK_TREE },
 433         { "receive-pack", cmd_receive_pack },
 434         { "reflog", cmd_reflog, RUN_SETUP },
 435         { "remote", cmd_remote, RUN_SETUP },
 436         { "remote-ext", cmd_remote_ext },
 437         { "remote-fd", cmd_remote_fd },
 438         { "repack", cmd_repack, RUN_SETUP },
 439         { "replace", cmd_replace, RUN_SETUP },
 440         { "rerere", cmd_rerere, RUN_SETUP },
 441         { "reset", cmd_reset, RUN_SETUP },
 442         { "rev-list", cmd_rev_list, RUN_SETUP },
 443         { "rev-parse", cmd_rev_parse },
 444         { "revert", cmd_revert, RUN_SETUP | NEED_WORK_TREE },
 445         { "rm", cmd_rm, RUN_SETUP },
 446         { "send-pack", cmd_send_pack, RUN_SETUP },
 447         { "shortlog", cmd_shortlog, RUN_SETUP_GENTLY | USE_PAGER },
 448         { "show", cmd_show, RUN_SETUP },
 449         { "show-branch", cmd_show_branch, RUN_SETUP },
 450         { "show-ref", cmd_show_ref, RUN_SETUP },
 451         { "stage", cmd_add, RUN_SETUP | NEED_WORK_TREE },
 452         { "status", cmd_status, RUN_SETUP | NEED_WORK_TREE },
 453         { "stripspace", cmd_stripspace },
 454         { "submodule--helper", cmd_submodule__helper, RUN_SETUP | SUPPORT_SUPER_PREFIX},
 455         { "symbolic-ref", cmd_symbolic_ref, RUN_SETUP },
 456         { "tag", cmd_tag, RUN_SETUP },
 457         { "unpack-file", cmd_unpack_file, RUN_SETUP },
 458         { "unpack-objects", cmd_unpack_objects, RUN_SETUP },
 459         { "update-index", cmd_update_index, RUN_SETUP },
 460         { "update-ref", cmd_update_ref, RUN_SETUP },
 461         { "update-server-info", cmd_update_server_info, RUN_SETUP },
 462         { "upload-archive", cmd_upload_archive },
 463         { "upload-archive--writer", cmd_upload_archive_writer },
 464         { "var", cmd_var, RUN_SETUP_GENTLY },
 465         { "verify-commit", cmd_verify_commit, RUN_SETUP },
 466         { "verify-pack", cmd_verify_pack },
 467         { "verify-tag", cmd_verify_tag, RUN_SETUP },
 468         { "version", cmd_version },
 469         { "whatchanged", cmd_whatchanged, RUN_SETUP },
 470         { "worktree", cmd_worktree, RUN_SETUP },
 471         { "write-tree", cmd_write_tree, RUN_SETUP },
 472 };
 473
 474 static struct cmd_struct *get_builtin(const char *s)
 475 {
 476         int i;
 477         for (i = 0; i < ARRAY_SIZE(commands); i++) {
 478                 struct cmd_struct *p = commands + i;
 479                 if (!strcmp(s, p->cmd))
 480                         return p;
 481         }
 482         return NULL;
 483 }
 484
 485 int is_builtin(const char *s)
 486 {
 487         return !!get_builtin(s);
 488 }
 489
 490 static void list_builtins(void)
 491 {
 492         int i;
 493         for (i = 0; i < ARRAY_SIZE(commands); i++)
 494                 printf("%s\n", commands[i].cmd);
 495 }
 496
 497 #ifdef STRIP_EXTENSION
 498 static void strip_extension(const char **argv)
 499 {
 500         size_t len;
 501
 502         if (strip_suffix(argv[0], STRIP_EXTENSION, &len))
 503                 argv[0] = xmemdupz(argv[0], len);
 504 }
 505 #else
 506 #define strip_extension(cmd)
 507 #endif
 508
 509 static void handle_builtin(int argc, const char **argv)
 510 {
 511         struct argv_array args = ARGV_ARRAY_INIT;
 512         const char *cmd;
 513         struct cmd_struct *builtin;
 514
 515         strip_extension(argv);
 516         cmd = argv[0];
 517
 518         /* Turn "git cmd --help" into "git help --exclude-guides cmd" */
 519         if (argc > 1 && !strcmp(argv[1], "--help")) {
 520                 int i;
 521
 522                 argv[1] = argv[0];
 523                 argv[0] = cmd = "help";
 524
 525                 for (i = 0; i < argc; i++) {
 526                         argv_array_push(&args, argv[i]);
 527                         if (!i)
 528                                 argv_array_push(&args, "--exclude-guides");
 529                 }
 530
 531                 argc++;
 532                 argv = args.argv;
 533         }
 534
 535         builtin = get_builtin(cmd);
 536         if (builtin)
 537                 exit(run_builtin(builtin, argc, argv));
 538         argv_array_clear(&args);
 539 }
 540
 541 static void execv_dashed_external(const char **argv)
 542 {
 543         struct child_process cmd = CHILD_PROCESS_INIT;
 544         int status;
 545
 546         if (get_super_prefix())
 547                 die("%s doesn't support --super-prefix", argv[0]);
 548
 549         if (use_pager == -1)
 550                 use_pager = check_pager_config(argv[0]);
 551         commit_pager_choice();
 552
 553         argv_array_pushf(&cmd.args, "git-%s", argv[0]);
 554         argv_array_pushv(&cmd.args, argv + 1);
 555         cmd.clean_on_exit = 1;
 556         cmd.wait_after_clean = 1;
 557         cmd.silent_exec_failure = 1;
 558
 559         trace_argv_printf(cmd.args.argv, "trace: exec:");
 560
 561         /*
 562          * If we fail because the command is not found, it is
 563          * OK to return. Otherwise, we just pass along the status code,
 564          * or our usual generic code if we were not even able to exec
 565          * the program.
 566          */
 567         status = run_command(&cmd);
 568         if (status >= 0)
 569                 exit(status);
 570         else if (errno != ENOENT)
 571                 exit(128);
 572 }
 573
 574 static int run_argv(int *argcp, const char ***argv)
 575 {
 576         int done_alias = 0;
 577
 578         while (1) {
 579                 /*
 580                  * If we tried alias and futzed with our environment,
 581                  * it no longer is safe to invoke builtins directly in
 582                  * general.  We have to spawn them as dashed externals.
 583                  *
 584                  * NEEDSWORK: if we can figure out cases
 585                  * where it is safe to do, we can avoid spawning a new
 586                  * process.
 587                  */
 588                 if (!done_alias)
 589                         handle_builtin(*argcp, *argv);
 590
 591                 /* .. then try the external ones */
 592                 execv_dashed_external(*argv);
 593
 594                 /* It could be an alias -- this works around the insanity
 595                  * of overriding "git log" with "git show" by having
 596                  * alias.log = show
 597                  */
 598                 if (done_alias)
 599                         break;
 600                 if (!handle_alias(argcp, argv))
 601                         break;
 602                 done_alias = 1;
 603         }
 604
 605         return done_alias;
 606 }
 607
 608 int cmd_main(int argc, const char **argv)
 609 {
 610         const char *cmd;
 611         int done_help = 0;
 612
 613         cmd = argv[0];
 614         if (!cmd)
 615                 cmd = "git-help";
 616         else {
 617                 const char *slash = find_last_dir_sep(cmd);
 618                 if (slash)
 619                         cmd = slash + 1;
 620         }
 621
 622         trace_command_performance(argv);
 623
 624         /*
 625          * "git-xxxx" is the same as "git xxxx", but we obviously:
 626          *
 627          *  - cannot take flags in between the "git" and the "xxxx".
 628          *  - cannot execute it externally (since it would just do
 629          *    the same thing over again)
 630          *
 631          * So we just directly call the builtin handler, and die if
 632          * that one cannot handle it.
 633          */
 634         if (skip_prefix(cmd, "git-", &cmd)) {
 635                 argv[0] = cmd;
 636                 handle_builtin(argc, argv);
 637                 die("cannot handle %s as a builtin", cmd);
 638         }
 639
 640         /* Look for flags.. */
 641         argv++;
 642         argc--;
 643         handle_options(&argv, &argc, NULL);
 644         if (argc > 0) {
 645                 /* translate --help and --version into commands */
 646                 skip_prefix(argv[0], "--", &argv[0]);
 647         } else {
 648                 /* The user didn't specify a command; give them help */
 649                 commit_pager_choice();
 650                 printf("usage: %s\n\n", git_usage_string);
 651                 list_common_cmds_help();
 652                 printf("\n%s\n", _(git_more_info_string));
 653                 exit(1);
 654         }
 655         cmd = argv[0];
 656
 657         /*
 658          * We use PATH to find git commands, but we prepend some higher
 659          * precedence paths: the "--exec-path" option, the GIT_EXEC_PATH
 660          * environment, and the $(gitexecdir) from the Makefile at build
 661          * time.
 662          */
 663         setup_path();
 664
 665         while (1) {
 666                 int was_alias = run_argv(&argc, &argv);
 667                 if (errno != ENOENT)
 668                         break;
 669                 if (was_alias) {
 670                         fprintf(stderr, "Expansion of alias '%s' failed; "
 671                                 "'%s' is not a git command\n",
 672                                 cmd, argv[0]);
 673                         exit(1);
 674                 }
 675                 if (!done_help) {
 676                         cmd = argv[0] = help_unknown_cmd(cmd);
 677                         done_help = 1;
 678                 } else
 679                         break;
 680         }
 681
 682         fprintf(stderr, "Failed to run command '%s': %s\n",
 683                 cmd, strerror(errno));
 684
 685         return 1;
 686 }