git.c

   1 #include "builtin.h"
   2 #include "config.h"
   3 #include "exec_cmd.h"
   4 #include "help.h"
   5 #include "run-command.h"
   6
   7 const char git_usage_string[] =
   8         "git [--version] [--help] [-C <path>] [-c name=value]\n"
   9         "           [--exec-path[=<path>]] [--html-path] [--man-path] [--info-path]\n"
  10         "           [-p | --paginate | --no-pager] [--no-replace-objects] [--bare]\n"
  11         "           [--git-dir=<path>] [--work-tree=<path>] [--namespace=<name>]\n"
  12         "           <command> [<args>]";
  13
  14 const char git_more_info_string[] =
  15         N_("'git help -a' and 'git help -g' list available subcommands and some\n"
  16            "concept guides. See 'git help <command>' or 'git help <concept>'\n"
  17            "to read about a specific subcommand or concept.");
  18
  19 static int use_pager = -1;
  20
  21 static void list_builtins(void);
  22
  23 static void commit_pager_choice(void) {
  24         switch (use_pager) {
  25         case 0:
  26                 setenv("GIT_PAGER", "cat", 1);
  27                 break;
  28         case 1:
  29                 setup_pager();
  30                 break;
  31         default:
  32                 break;
  33         }
  34 }
  35
  36 static int handle_options(const char ***argv, int *argc, int *envchanged)
  37 {
  38         const char **orig_argv = *argv;
  39
  40         while (*argc > 0) {
  41                 const char *cmd = (*argv)[0];
  42                 if (cmd[0] != '-')
  43                         break;
  44
  45                 /*
  46                  * For legacy reasons, the "version" and "help"
  47                  * commands can be written with "--" prepended
  48                  * to make them look like flags.
  49                  */
  50                 if (!strcmp(cmd, "--help") || !strcmp(cmd, "--version"))
  51                         break;
  52
  53                 /*
  54                  * Check remaining flags.
  55                  */
  56                 if (skip_prefix(cmd, "--exec-path", &cmd)) {
  57                         if (*cmd == '=')
  58                                 git_set_argv_exec_path(cmd + 1);
  59                         else {
  60                                 puts(git_exec_path());
  61                                 exit(0);
  62                         }
  63                 } else if (!strcmp(cmd, "--html-path")) {
  64                         puts(system_path(GIT_HTML_PATH));
  65                         exit(0);
  66                 } else if (!strcmp(cmd, "--man-path")) {
  67                         puts(system_path(GIT_MAN_PATH));
  68                         exit(0);
  69                 } else if (!strcmp(cmd, "--info-path")) {
  70                         puts(system_path(GIT_INFO_PATH));
  71                         exit(0);
  72                 } else if (!strcmp(cmd, "-p") || !strcmp(cmd, "--paginate")) {
  73                         use_pager = 1;
  74                 } else if (!strcmp(cmd, "--no-pager")) {
  75                         use_pager = 0;
  76                         if (envchanged)
  77                                 *envchanged = 1;
  78                 } else if (!strcmp(cmd, "--no-replace-objects")) {
  79                         check_replace_refs = 0;
  80                         setenv(NO_REPLACE_OBJECTS_ENVIRONMENT, "1", 1);
  81                         if (envchanged)
  82                                 *envchanged = 1;
  83                 } else if (!strcmp(cmd, "--git-dir")) {
  84                         if (*argc < 2) {
  85                                 fprintf(stderr, "No directory given for --git-dir.\n" );
  86                                 usage(git_usage_string);
  87                         }
  88                         setenv(GIT_DIR_ENVIRONMENT, (*argv)[1], 1);
  89                         if (envchanged)
  90                                 *envchanged = 1;
  91                         (*argv)++;
  92                         (*argc)--;
  93                 } else if (skip_prefix(cmd, "--git-dir=", &cmd)) {
  94                         setenv(GIT_DIR_ENVIRONMENT, cmd, 1);
  95                         if (envchanged)
  96                                 *envchanged = 1;
  97                 } else if (!strcmp(cmd, "--namespace")) {
  98                         if (*argc < 2) {
  99                                 fprintf(stderr, "No namespace given for --namespace.\n" );
 100                                 usage(git_usage_string);
 101                         }
 102                         setenv(GIT_NAMESPACE_ENVIRONMENT, (*argv)[1], 1);
 103                         if (envchanged)
 104                                 *envchanged = 1;
 105                         (*argv)++;
 106                         (*argc)--;
 107                 } else if (skip_prefix(cmd, "--namespace=", &cmd)) {
 108                         setenv(GIT_NAMESPACE_ENVIRONMENT, cmd, 1);
 109                         if (envchanged)
 110                                 *envchanged = 1;
 111                 } else if (!strcmp(cmd, "--work-tree")) {
 112                         if (*argc < 2) {
 113                                 fprintf(stderr, "No directory given for --work-tree.\n" );
 114                                 usage(git_usage_string);
 115                         }
 116                         setenv(GIT_WORK_TREE_ENVIRONMENT, (*argv)[1], 1);
 117                         if (envchanged)
 118                                 *envchanged = 1;
 119                         (*argv)++;
 120                         (*argc)--;
 121                 } else if (skip_prefix(cmd, "--work-tree=", &cmd)) {
 122                         setenv(GIT_WORK_TREE_ENVIRONMENT, cmd, 1);
 123                         if (envchanged)
 124                                 *envchanged = 1;
 125                 } else if (!strcmp(cmd, "--super-prefix")) {
 126                         if (*argc < 2) {
 127                                 fprintf(stderr, "No prefix given for --super-prefix.\n" );
 128                                 usage(git_usage_string);
 129                         }
 130                         setenv(GIT_SUPER_PREFIX_ENVIRONMENT, (*argv)[1], 1);
 131                         if (envchanged)
 132                                 *envchanged = 1;
 133                         (*argv)++;
 134                         (*argc)--;
 135                 } else if (skip_prefix(cmd, "--super-prefix=", &cmd)) {
 136                         setenv(GIT_SUPER_PREFIX_ENVIRONMENT, cmd, 1);
 137                         if (envchanged)
 138                                 *envchanged = 1;
 139                 } else if (!strcmp(cmd, "--bare")) {
 140                         char *cwd = xgetcwd();
 141                         is_bare_repository_cfg = 1;
 142                         setenv(GIT_DIR_ENVIRONMENT, cwd, 0);
 143                         free(cwd);
 144                         setenv(GIT_IMPLICIT_WORK_TREE_ENVIRONMENT, "0", 1);
 145                         if (envchanged)
 146                                 *envchanged = 1;
 147                 } else if (!strcmp(cmd, "-c")) {
 148                         if (*argc < 2) {
 149                                 fprintf(stderr, "-c expects a configuration string\n" );
 150                                 usage(git_usage_string);
 151                         }
 152                         git_config_push_parameter((*argv)[1]);
 153                         (*argv)++;
 154                         (*argc)--;
 155                 } else if (!strcmp(cmd, "--literal-pathspecs")) {
 156                         setenv(GIT_LITERAL_PATHSPECS_ENVIRONMENT, "1", 1);
 157                         if (envchanged)
 158                                 *envchanged = 1;
 159                 } else if (!strcmp(cmd, "--no-literal-pathspecs")) {
 160                         setenv(GIT_LITERAL_PATHSPECS_ENVIRONMENT, "0", 1);
 161                         if (envchanged)
 162                                 *envchanged = 1;
 163                 } else if (!strcmp(cmd, "--glob-pathspecs")) {
 164                         setenv(GIT_GLOB_PATHSPECS_ENVIRONMENT, "1", 1);
 165                         if (envchanged)
 166                                 *envchanged = 1;
 167                 } else if (!strcmp(cmd, "--noglob-pathspecs")) {
 168                         setenv(GIT_NOGLOB_PATHSPECS_ENVIRONMENT, "1", 1);
 169                         if (envchanged)
 170                                 *envchanged = 1;
 171                 } else if (!strcmp(cmd, "--icase-pathspecs")) {
 172                         setenv(GIT_ICASE_PATHSPECS_ENVIRONMENT, "1", 1);
 173                         if (envchanged)
 174                                 *envchanged = 1;
 175                 } else if (!strcmp(cmd, "--shallow-file")) {
 176                         (*argv)++;
 177                         (*argc)--;
 178                         set_alternate_shallow_file((*argv)[0], 1);
 179                         if (envchanged)
 180                                 *envchanged = 1;
 181                 } else if (!strcmp(cmd, "-C")) {
 182                         if (*argc < 2) {
 183                                 fprintf(stderr, "No directory given for -C.\n" );
 184                                 usage(git_usage_string);
 185                         }
 186                         if ((*argv)[1][0]) {
 187                                 if (chdir((*argv)[1]))
 188                                         die_errno("Cannot change to '%s'", (*argv)[1]);
 189                                 if (envchanged)
 190                                         *envchanged = 1;
 191                         }
 192                         (*argv)++;
 193                         (*argc)--;
 194                 } else if (!strcmp(cmd, "--list-builtins")) {
 195                         list_builtins();
 196                         exit(0);
 197                 } else {
 198                         fprintf(stderr, "Unknown option: %s\n", cmd);
 199                         usage(git_usage_string);
 200                 }
 201
 202                 (*argv)++;
 203                 (*argc)--;
 204         }
 205         return (*argv) - orig_argv;
 206 }
 207
 208 static int handle_alias(int *argcp, const char ***argv)
 209 {
 210         int envchanged = 0, ret = 0, saved_errno = errno;
 211         int count, option_count;
 212         const char **new_argv;
 213         const char *alias_command;
 214         char *alias_string;
 215
 216         alias_command = (*argv)[0];
 217         alias_string = alias_lookup(alias_command);
 218         if (alias_string) {
 219                 if (alias_string[0] == '!') {
 220                         struct child_process child = CHILD_PROCESS_INIT;
 221                         int nongit_ok;
 222
 223                         /* Aliases expect GIT_PREFIX, GIT_DIR etc to be set */
 224                         setup_git_directory_gently(&nongit_ok);
 225
 226                         commit_pager_choice();
 227
 228                         child.use_shell = 1;
 229                         argv_array_push(&child.args, alias_string + 1);
 230                         argv_array_pushv(&child.args, (*argv) + 1);
 231
 232                         ret = run_command(&child);
 233                         if (ret >= 0)   /* normal exit */
 234                                 exit(ret);
 235
 236                         die_errno("While expanding alias '%s': '%s'",
 237                             alias_command, alias_string + 1);
 238                 }
 239                 count = split_cmdline(alias_string, &new_argv);
 240                 if (count < 0)
 241                         die("Bad alias.%s string: %s", alias_command,
 242                             split_cmdline_strerror(count));
 243                 option_count = handle_options(&new_argv, &count, &envchanged);
 244                 if (envchanged)
 245                         die("alias '%s' changes environment variables\n"
 246                                  "You can use '!git' in the alias to do this.",
 247                                  alias_command);
 248                 memmove(new_argv - option_count, new_argv,
 249                                 count * sizeof(char *));
 250                 new_argv -= option_count;
 251
 252                 if (count < 1)
 253                         die("empty alias for %s", alias_command);
 254
 255                 if (!strcmp(alias_command, new_argv[0]))
 256                         die("recursive alias: %s", alias_command);
 257
 258                 trace_argv_printf(new_argv,
 259                                   "trace: alias expansion: %s =>",
 260                                   alias_command);
 261
 262                 REALLOC_ARRAY(new_argv, count + *argcp);
 263                 /* insert after command name */
 264                 memcpy(new_argv + count, *argv + 1, sizeof(char *) * *argcp);
 265
 266                 *argv = new_argv;
 267                 *argcp += count - 1;
 268
 269                 ret = 1;
 270         }
 271
 272         errno = saved_errno;
 273
 274         return ret;
 275 }
 276
 277 #define RUN_SETUP               (1<<0)
 278 #define RUN_SETUP_GENTLY        (1<<1)
 279 #define USE_PAGER               (1<<2)
 280 /*
 281  * require working tree to be present -- anything uses this needs
 282  * RUN_SETUP for reading from the configuration file.
 283  */
 284 #define NEED_WORK_TREE          (1<<3)
 285 #define SUPPORT_SUPER_PREFIX    (1<<4)
 286
 287 struct cmd_struct {
 288         const char *cmd;
 289         int (*fn)(int, const char **, const char *);
 290         int option;
 291 };
 292
 293 static int run_builtin(struct cmd_struct *p, int argc, const char **argv)
 294 {
 295         int status, help;
 296         struct stat st;
 297         const char *prefix;
 298
 299         prefix = NULL;
 300         help = argc == 2 && !strcmp(argv[1], "-h");
 301         if (!help) {
 302                 if (p->option & RUN_SETUP)
 303                         prefix = setup_git_directory();
 304                 else if (p->option & RUN_SETUP_GENTLY) {
 305                         int nongit_ok;
 306                         prefix = setup_git_directory_gently(&nongit_ok);
 307                 }
 308
 309                 if (use_pager == -1 && p->option & (RUN_SETUP | RUN_SETUP_GENTLY))
 310                         use_pager = check_pager_config(p->cmd);
 311                 if (use_pager == -1 && p->option & USE_PAGER)
 312                         use_pager = 1;
 313
 314                 if ((p->option & (RUN_SETUP | RUN_SETUP_GENTLY)) &&
 315                     startup_info->have_repository) /* get_git_dir() may set up repo, avoid that */
 316                         trace_repo_setup(prefix);
 317         }
 318         commit_pager_choice();
 319
 320         if (!help && get_super_prefix()) {
 321                 if (!(p->option & SUPPORT_SUPER_PREFIX))
 322                         die("%s doesn't support --super-prefix", p->cmd);
 323         }
 324
 325         if (!help && p->option & NEED_WORK_TREE)
 326                 setup_work_tree();
 327
 328         trace_argv_printf(argv, "trace: built-in: git");
 329
 330         status = p->fn(argc, argv, prefix);
 331         if (status)
 332                 return status;
 333
 334         /* Somebody closed stdout? */
 335         if (fstat(fileno(stdout), &st))
 336                 return 0;
 337         /* Ignore write errors for pipes and sockets.. */
 338         if (S_ISFIFO(st.st_mode) || S_ISSOCK(st.st_mode))
 339                 return 0;
 340
 341         /* Check for ENOSPC and EIO errors.. */
 342         if (fflush(stdout))
 343                 die_errno("write failure on standard output");
 344         if (ferror(stdout))
 345                 die("unknown write failure on standard output");
 346         if (fclose(stdout))
 347                 die_errno("close failed on standard output");
 348         return 0;
 349 }
 350
 351 static struct cmd_struct commands[] = {
 352         { "add", cmd_add, RUN_SETUP | NEED_WORK_TREE },
 353         { "am", cmd_am, RUN_SETUP | NEED_WORK_TREE },
 354         { "annotate", cmd_annotate, RUN_SETUP },
 355         { "apply", cmd_apply, RUN_SETUP_GENTLY },
 356         { "archive", cmd_archive, RUN_SETUP_GENTLY },
 357         { "bisect--helper", cmd_bisect__helper, RUN_SETUP },
 358         { "blame", cmd_blame, RUN_SETUP },
 359         { "branch", cmd_branch, RUN_SETUP },
 360         { "bundle", cmd_bundle, RUN_SETUP_GENTLY },
 361         { "cat-file", cmd_cat_file, RUN_SETUP },
 362         { "check-attr", cmd_check_attr, RUN_SETUP },
 363         { "check-ignore", cmd_check_ignore, RUN_SETUP | NEED_WORK_TREE },
 364         { "check-mailmap", cmd_check_mailmap, RUN_SETUP },
 365         { "check-ref-format", cmd_check_ref_format },
 366         { "checkout", cmd_checkout, RUN_SETUP | NEED_WORK_TREE },
 367         { "checkout-index", cmd_checkout_index,
 368                 RUN_SETUP | NEED_WORK_TREE},
 369         { "cherry", cmd_cherry, RUN_SETUP },
 370         { "cherry-pick", cmd_cherry_pick, RUN_SETUP | NEED_WORK_TREE },
 371         { "clean", cmd_clean, RUN_SETUP | NEED_WORK_TREE },
 372         { "clone", cmd_clone },
 373         { "column", cmd_column, RUN_SETUP_GENTLY },
 374         { "commit", cmd_commit, RUN_SETUP | NEED_WORK_TREE },
 375         { "commit-tree", cmd_commit_tree, RUN_SETUP },
 376         { "config", cmd_config, RUN_SETUP_GENTLY },
 377         { "count-objects", cmd_count_objects, RUN_SETUP },
 378         { "credential", cmd_credential, RUN_SETUP_GENTLY },
 379         { "describe", cmd_describe, RUN_SETUP },
 380         { "diff", cmd_diff },
 381         { "diff-files", cmd_diff_files, RUN_SETUP | NEED_WORK_TREE },
 382         { "diff-index", cmd_diff_index, RUN_SETUP },
 383         { "diff-tree", cmd_diff_tree, RUN_SETUP },
 384         { "difftool", cmd_difftool, RUN_SETUP | NEED_WORK_TREE },
 385         { "fast-export", cmd_fast_export, RUN_SETUP },
 386         { "fetch", cmd_fetch, RUN_SETUP },
 387         { "fetch-pack", cmd_fetch_pack, RUN_SETUP },
 388         { "fmt-merge-msg", cmd_fmt_merge_msg, RUN_SETUP },
 389         { "for-each-ref", cmd_for_each_ref, RUN_SETUP },
 390         { "format-patch", cmd_format_patch, RUN_SETUP },
 391         { "fsck", cmd_fsck, RUN_SETUP },
 392         { "fsck-objects", cmd_fsck, RUN_SETUP },
 393         { "gc", cmd_gc, RUN_SETUP },
 394         { "get-tar-commit-id", cmd_get_tar_commit_id },
 395         { "grep", cmd_grep, RUN_SETUP_GENTLY | SUPPORT_SUPER_PREFIX },
 396         { "hash-object", cmd_hash_object },
 397         { "help", cmd_help },
 398         { "index-pack", cmd_index_pack, RUN_SETUP_GENTLY },
 399         { "init", cmd_init_db },
 400         { "init-db", cmd_init_db },
 401         { "interpret-trailers", cmd_interpret_trailers, RUN_SETUP_GENTLY },
 402         { "log", cmd_log, RUN_SETUP },
 403         { "ls-files", cmd_ls_files, RUN_SETUP },
 404         { "ls-remote", cmd_ls_remote, RUN_SETUP_GENTLY },
 405         { "ls-tree", cmd_ls_tree, RUN_SETUP },
 406         { "mailinfo", cmd_mailinfo, RUN_SETUP_GENTLY },
 407         { "mailsplit", cmd_mailsplit },
 408         { "merge", cmd_merge, RUN_SETUP | NEED_WORK_TREE },
 409         { "merge-base", cmd_merge_base, RUN_SETUP },
 410         { "merge-file", cmd_merge_file, RUN_SETUP_GENTLY },
 411         { "merge-index", cmd_merge_index, RUN_SETUP },
 412         { "merge-ours", cmd_merge_ours, RUN_SETUP },
 413         { "merge-recursive", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE },
 414         { "merge-recursive-ours", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE },
 415         { "merge-recursive-theirs", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE },
 416         { "merge-subtree", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE },
 417         { "merge-tree", cmd_merge_tree, RUN_SETUP },
 418         { "mktag", cmd_mktag, RUN_SETUP },
 419         { "mktree", cmd_mktree, RUN_SETUP },
 420         { "mv", cmd_mv, RUN_SETUP | NEED_WORK_TREE },
 421         { "name-rev", cmd_name_rev, RUN_SETUP },
 422         { "notes", cmd_notes, RUN_SETUP },
 423         { "pack-objects", cmd_pack_objects, RUN_SETUP },
 424         { "pack-redundant", cmd_pack_redundant, RUN_SETUP },
 425         { "pack-refs", cmd_pack_refs, RUN_SETUP },
 426         { "patch-id", cmd_patch_id, RUN_SETUP_GENTLY },
 427         { "pickaxe", cmd_blame, RUN_SETUP },
 428         { "prune", cmd_prune, RUN_SETUP },
 429         { "prune-packed", cmd_prune_packed, RUN_SETUP },
 430         { "pull", cmd_pull, RUN_SETUP | NEED_WORK_TREE },
 431         { "push", cmd_push, RUN_SETUP },
 432         { "read-tree", cmd_read_tree, RUN_SETUP | SUPPORT_SUPER_PREFIX},
 433         { "rebase--helper", cmd_rebase__helper, RUN_SETUP | NEED_WORK_TREE },
 434         { "receive-pack", cmd_receive_pack },
 435         { "reflog", cmd_reflog, RUN_SETUP },
 436         { "remote", cmd_remote, RUN_SETUP },
 437         { "remote-ext", cmd_remote_ext },
 438         { "remote-fd", cmd_remote_fd },
 439         { "repack", cmd_repack, RUN_SETUP },
 440         { "replace", cmd_replace, RUN_SETUP },
 441         { "rerere", cmd_rerere, RUN_SETUP },
 442         { "reset", cmd_reset, RUN_SETUP },
 443         { "rev-list", cmd_rev_list, RUN_SETUP },
 444         { "rev-parse", cmd_rev_parse },
 445         { "revert", cmd_revert, RUN_SETUP | NEED_WORK_TREE },
 446         { "rm", cmd_rm, RUN_SETUP },
 447         { "send-pack", cmd_send_pack, RUN_SETUP },
 448         { "shortlog", cmd_shortlog, RUN_SETUP_GENTLY | USE_PAGER },
 449         { "show", cmd_show, RUN_SETUP },
 450         { "show-branch", cmd_show_branch, RUN_SETUP },
 451         { "show-ref", cmd_show_ref, RUN_SETUP },
 452         { "stage", cmd_add, RUN_SETUP | NEED_WORK_TREE },
 453         { "status", cmd_status, RUN_SETUP | NEED_WORK_TREE },
 454         { "stripspace", cmd_stripspace },
 455         { "submodule--helper", cmd_submodule__helper, RUN_SETUP | SUPPORT_SUPER_PREFIX},
 456         { "symbolic-ref", cmd_symbolic_ref, RUN_SETUP },
 457         { "tag", cmd_tag, RUN_SETUP },
 458         { "unpack-file", cmd_unpack_file, RUN_SETUP },
 459         { "unpack-objects", cmd_unpack_objects, RUN_SETUP },
 460         { "update-index", cmd_update_index, RUN_SETUP },
 461         { "update-ref", cmd_update_ref, RUN_SETUP },
 462         { "update-server-info", cmd_update_server_info, RUN_SETUP },
 463         { "upload-archive", cmd_upload_archive },
 464         { "upload-archive--writer", cmd_upload_archive_writer },
 465         { "var", cmd_var, RUN_SETUP_GENTLY },
 466         { "verify-commit", cmd_verify_commit, RUN_SETUP },
 467         { "verify-pack", cmd_verify_pack },
 468         { "verify-tag", cmd_verify_tag, RUN_SETUP },
 469         { "version", cmd_version },
 470         { "whatchanged", cmd_whatchanged, RUN_SETUP },
 471         { "worktree", cmd_worktree, RUN_SETUP },
 472         { "write-tree", cmd_write_tree, RUN_SETUP },
 473 };
 474
 475 static struct cmd_struct *get_builtin(const char *s)
 476 {
 477         int i;
 478         for (i = 0; i < ARRAY_SIZE(commands); i++) {
 479                 struct cmd_struct *p = commands + i;
 480                 if (!strcmp(s, p->cmd))
 481                         return p;
 482         }
 483         return NULL;
 484 }
 485
 486 int is_builtin(const char *s)
 487 {
 488         return !!get_builtin(s);
 489 }
 490
 491 static void list_builtins(void)
 492 {
 493         int i;
 494         for (i = 0; i < ARRAY_SIZE(commands); i++)
 495                 printf("%s\n", commands[i].cmd);
 496 }
 497
 498 #ifdef STRIP_EXTENSION
 499 static void strip_extension(const char **argv)
 500 {
 501         size_t len;
 502
 503         if (strip_suffix(argv[0], STRIP_EXTENSION, &len))
 504                 argv[0] = xmemdupz(argv[0], len);
 505 }
 506 #else
 507 #define strip_extension(cmd)
 508 #endif
 509
 510 static void handle_builtin(int argc, const char **argv)
 511 {
 512         struct argv_array args = ARGV_ARRAY_INIT;
 513         const char *cmd;
 514         struct cmd_struct *builtin;
 515
 516         strip_extension(argv);
 517         cmd = argv[0];
 518
 519         /* Turn "git cmd --help" into "git help --exclude-guides cmd" */
 520         if (argc > 1 && !strcmp(argv[1], "--help")) {
 521                 int i;
 522
 523                 argv[1] = argv[0];
 524                 argv[0] = cmd = "help";
 525
 526                 for (i = 0; i < argc; i++) {
 527                         argv_array_push(&args, argv[i]);
 528                         if (!i)
 529                                 argv_array_push(&args, "--exclude-guides");
 530                 }
 531
 532                 argc++;
 533                 argv = args.argv;
 534         }
 535
 536         builtin = get_builtin(cmd);
 537         if (builtin)
 538                 exit(run_builtin(builtin, argc, argv));
 539         argv_array_clear(&args);
 540 }
 541
 542 static void execv_dashed_external(const char **argv)
 543 {
 544         struct child_process cmd = CHILD_PROCESS_INIT;
 545         int status;
 546
 547         if (get_super_prefix())
 548                 die("%s doesn't support --super-prefix", argv[0]);
 549
 550         if (use_pager == -1)
 551                 use_pager = check_pager_config(argv[0]);
 552         commit_pager_choice();
 553
 554         argv_array_pushf(&cmd.args, "git-%s", argv[0]);
 555         argv_array_pushv(&cmd.args, argv + 1);
 556         cmd.clean_on_exit = 1;
 557         cmd.wait_after_clean = 1;
 558         cmd.silent_exec_failure = 1;
 559
 560         trace_argv_printf(cmd.args.argv, "trace: exec:");
 561
 562         /*
 563          * If we fail because the command is not found, it is
 564          * OK to return. Otherwise, we just pass along the status code,
 565          * or our usual generic code if we were not even able to exec
 566          * the program.
 567          */
 568         status = run_command(&cmd);
 569         if (status >= 0)
 570                 exit(status);
 571         else if (errno != ENOENT)
 572                 exit(128);
 573 }
 574
 575 static int run_argv(int *argcp, const char ***argv)
 576 {
 577         int done_alias = 0;
 578
 579         while (1) {
 580                 /*
 581                  * If we tried alias and futzed with our environment,
 582                  * it no longer is safe to invoke builtins directly in
 583                  * general.  We have to spawn them as dashed externals.
 584                  *
 585                  * NEEDSWORK: if we can figure out cases
 586                  * where it is safe to do, we can avoid spawning a new
 587                  * process.
 588                  */
 589                 if (!done_alias)
 590                         handle_builtin(*argcp, *argv);
 591
 592                 /* .. then try the external ones */
 593                 execv_dashed_external(*argv);
 594
 595                 /* It could be an alias -- this works around the insanity
 596                  * of overriding "git log" with "git show" by having
 597                  * alias.log = show
 598                  */
 599                 if (done_alias)
 600                         break;
 601                 if (!handle_alias(argcp, argv))
 602                         break;
 603                 done_alias = 1;
 604         }
 605
 606         return done_alias;
 607 }
 608
 609 int cmd_main(int argc, const char **argv)
 610 {
 611         const char *cmd;
 612         int done_help = 0;
 613
 614         cmd = argv[0];
 615         if (!cmd)
 616                 cmd = "git-help";
 617         else {
 618                 const char *slash = find_last_dir_sep(cmd);
 619                 if (slash)
 620                         cmd = slash + 1;
 621         }
 622
 623         trace_command_performance(argv);
 624
 625         /*
 626          * "git-xxxx" is the same as "git xxxx", but we obviously:
 627          *
 628          *  - cannot take flags in between the "git" and the "xxxx".
 629          *  - cannot execute it externally (since it would just do
 630          *    the same thing over again)
 631          *
 632          * So we just directly call the builtin handler, and die if
 633          * that one cannot handle it.
 634          */
 635         if (skip_prefix(cmd, "git-", &cmd)) {
 636                 argv[0] = cmd;
 637                 handle_builtin(argc, argv);
 638                 die("cannot handle %s as a builtin", cmd);
 639         }
 640
 641         /* Look for flags.. */
 642         argv++;
 643         argc--;
 644         handle_options(&argv, &argc, NULL);
 645         if (argc > 0) {
 646                 /* translate --help and --version into commands */
 647                 skip_prefix(argv[0], "--", &argv[0]);
 648         } else {
 649                 /* The user didn't specify a command; give them help */
 650                 commit_pager_choice();
 651                 printf("usage: %s\n\n", git_usage_string);
 652                 list_common_cmds_help();
 653                 printf("\n%s\n", _(git_more_info_string));
 654                 exit(1);
 655         }
 656         cmd = argv[0];
 657
 658         /*
 659          * We use PATH to find git commands, but we prepend some higher
 660          * precedence paths: the "--exec-path" option, the GIT_EXEC_PATH
 661          * environment, and the $(gitexecdir) from the Makefile at build
 662          * time.
 663          */
 664         setup_path();
 665
 666         while (1) {
 667                 int was_alias = run_argv(&argc, &argv);
 668                 if (errno != ENOENT)
 669                         break;
 670                 if (was_alias) {
 671                         fprintf(stderr, "Expansion of alias '%s' failed; "
 672                                 "'%s' is not a git command\n",
 673                                 cmd, argv[0]);
 674                         exit(1);
 675                 }
 676                 if (!done_help) {
 677                         cmd = argv[0] = help_unknown_cmd(cmd);
 678                         done_help = 1;
 679                 } else
 680                         break;
 681         }
 682
 683         fprintf(stderr, "Failed to run command '%s': %s\n",
 684                 cmd, strerror(errno));
 685
 686         return 1;
 687 }