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 static char *orig_cwd;
  20 static const char *env_names[] = {
  21         GIT_DIR_ENVIRONMENT,
  22         GIT_WORK_TREE_ENVIRONMENT,
  23         GIT_IMPLICIT_WORK_TREE_ENVIRONMENT,
  24         GIT_PREFIX_ENVIRONMENT
  25 };
  26 static char *orig_env[4];
  27 static int save_restore_env_balance;
  28
  29 static void list_builtins(void);
  30
  31 static void save_env_before_alias(void)
  32 {
  33         int i;
  34
  35         assert(save_restore_env_balance == 0);
  36         save_restore_env_balance = 1;
  37         orig_cwd = xgetcwd();
  38         for (i = 0; i < ARRAY_SIZE(env_names); i++) {
  39                 orig_env[i] = getenv(env_names[i]);
  40                 orig_env[i] = xstrdup_or_null(orig_env[i]);
  41         }
  42 }
  43
  44 static void restore_env(int external_alias)
  45 {
  46         int i;
  47
  48         assert(save_restore_env_balance == 1);
  49         save_restore_env_balance = 0;
  50         if (!external_alias && orig_cwd && chdir(orig_cwd))
  51                 die_errno("could not move to %s", orig_cwd);
  52         free(orig_cwd);
  53         for (i = 0; i < ARRAY_SIZE(env_names); i++) {
  54                 if (external_alias &&
  55                     !strcmp(env_names[i], GIT_PREFIX_ENVIRONMENT))
  56                         continue;
  57                 if (orig_env[i]) {
  58                         setenv(env_names[i], orig_env[i], 1);
  59                         free(orig_env[i]);
  60                 } else {
  61                         unsetenv(env_names[i]);
  62                 }
  63         }
  64 }
  65
  66 static void commit_pager_choice(void) {
  67         switch (use_pager) {
  68         case 0:
  69                 setenv("GIT_PAGER", "cat", 1);
  70                 break;
  71         case 1:
  72                 setup_pager();
  73                 break;
  74         default:
  75                 break;
  76         }
  77 }
  78
  79 static int handle_options(const char ***argv, int *argc, int *envchanged)
  80 {
  81         const char **orig_argv = *argv;
  82
  83         while (*argc > 0) {
  84                 const char *cmd = (*argv)[0];
  85                 if (cmd[0] != '-')
  86                         break;
  87
  88                 /*
  89                  * For legacy reasons, the "version" and "help"
  90                  * commands can be written with "--" prepended
  91                  * to make them look like flags.
  92                  */
  93                 if (!strcmp(cmd, "--help") || !strcmp(cmd, "--version"))
  94                         break;
  95
  96                 /*
  97                  * Check remaining flags.
  98                  */
  99                 if (skip_prefix(cmd, "--exec-path", &cmd)) {
 100                         if (*cmd == '=')
 101                                 git_set_argv_exec_path(cmd + 1);
 102                         else {
 103                                 puts(git_exec_path());
 104                                 exit(0);
 105                         }
 106                 } else if (!strcmp(cmd, "--html-path")) {
 107                         puts(system_path(GIT_HTML_PATH));
 108                         exit(0);
 109                 } else if (!strcmp(cmd, "--man-path")) {
 110                         puts(system_path(GIT_MAN_PATH));
 111                         exit(0);
 112                 } else if (!strcmp(cmd, "--info-path")) {
 113                         puts(system_path(GIT_INFO_PATH));
 114                         exit(0);
 115                 } else if (!strcmp(cmd, "-p") || !strcmp(cmd, "--paginate")) {
 116                         use_pager = 1;
 117                 } else if (!strcmp(cmd, "--no-pager")) {
 118                         use_pager = 0;
 119                         if (envchanged)
 120                                 *envchanged = 1;
 121                 } else if (!strcmp(cmd, "--no-replace-objects")) {
 122                         check_replace_refs = 0;
 123                         setenv(NO_REPLACE_OBJECTS_ENVIRONMENT, "1", 1);
 124                         if (envchanged)
 125                                 *envchanged = 1;
 126                 } else if (!strcmp(cmd, "--git-dir")) {
 127                         if (*argc < 2) {
 128                                 fprintf(stderr, "No directory given for --git-dir.\n" );
 129                                 usage(git_usage_string);
 130                         }
 131                         setenv(GIT_DIR_ENVIRONMENT, (*argv)[1], 1);
 132                         if (envchanged)
 133                                 *envchanged = 1;
 134                         (*argv)++;
 135                         (*argc)--;
 136                 } else if (skip_prefix(cmd, "--git-dir=", &cmd)) {
 137                         setenv(GIT_DIR_ENVIRONMENT, cmd, 1);
 138                         if (envchanged)
 139                                 *envchanged = 1;
 140                 } else if (!strcmp(cmd, "--namespace")) {
 141                         if (*argc < 2) {
 142                                 fprintf(stderr, "No namespace given for --namespace.\n" );
 143                                 usage(git_usage_string);
 144                         }
 145                         setenv(GIT_NAMESPACE_ENVIRONMENT, (*argv)[1], 1);
 146                         if (envchanged)
 147                                 *envchanged = 1;
 148                         (*argv)++;
 149                         (*argc)--;
 150                 } else if (skip_prefix(cmd, "--namespace=", &cmd)) {
 151                         setenv(GIT_NAMESPACE_ENVIRONMENT, cmd, 1);
 152                         if (envchanged)
 153                                 *envchanged = 1;
 154                 } else if (!strcmp(cmd, "--work-tree")) {
 155                         if (*argc < 2) {
 156                                 fprintf(stderr, "No directory given for --work-tree.\n" );
 157                                 usage(git_usage_string);
 158                         }
 159                         setenv(GIT_WORK_TREE_ENVIRONMENT, (*argv)[1], 1);
 160                         if (envchanged)
 161                                 *envchanged = 1;
 162                         (*argv)++;
 163                         (*argc)--;
 164                 } else if (skip_prefix(cmd, "--work-tree=", &cmd)) {
 165                         setenv(GIT_WORK_TREE_ENVIRONMENT, cmd, 1);
 166                         if (envchanged)
 167                                 *envchanged = 1;
 168                 } else if (!strcmp(cmd, "--super-prefix")) {
 169                         if (*argc < 2) {
 170                                 fprintf(stderr, "No prefix given for --super-prefix.\n" );
 171                                 usage(git_usage_string);
 172                         }
 173                         setenv(GIT_SUPER_PREFIX_ENVIRONMENT, (*argv)[1], 1);
 174                         if (envchanged)
 175                                 *envchanged = 1;
 176                         (*argv)++;
 177                         (*argc)--;
 178                 } else if (skip_prefix(cmd, "--super-prefix=", &cmd)) {
 179                         setenv(GIT_SUPER_PREFIX_ENVIRONMENT, cmd, 1);
 180                         if (envchanged)
 181                                 *envchanged = 1;
 182                 } else if (!strcmp(cmd, "--bare")) {
 183                         char *cwd = xgetcwd();
 184                         is_bare_repository_cfg = 1;
 185                         setenv(GIT_DIR_ENVIRONMENT, cwd, 0);
 186                         free(cwd);
 187                         setenv(GIT_IMPLICIT_WORK_TREE_ENVIRONMENT, "0", 1);
 188                         if (envchanged)
 189                                 *envchanged = 1;
 190                 } else if (!strcmp(cmd, "-c")) {
 191                         if (*argc < 2) {
 192                                 fprintf(stderr, "-c expects a configuration string\n" );
 193                                 usage(git_usage_string);
 194                         }
 195                         git_config_push_parameter((*argv)[1]);
 196                         (*argv)++;
 197                         (*argc)--;
 198                 } else if (!strcmp(cmd, "--literal-pathspecs")) {
 199                         setenv(GIT_LITERAL_PATHSPECS_ENVIRONMENT, "1", 1);
 200                         if (envchanged)
 201                                 *envchanged = 1;
 202                 } else if (!strcmp(cmd, "--no-literal-pathspecs")) {
 203                         setenv(GIT_LITERAL_PATHSPECS_ENVIRONMENT, "0", 1);
 204                         if (envchanged)
 205                                 *envchanged = 1;
 206                 } else if (!strcmp(cmd, "--glob-pathspecs")) {
 207                         setenv(GIT_GLOB_PATHSPECS_ENVIRONMENT, "1", 1);
 208                         if (envchanged)
 209                                 *envchanged = 1;
 210                 } else if (!strcmp(cmd, "--noglob-pathspecs")) {
 211                         setenv(GIT_NOGLOB_PATHSPECS_ENVIRONMENT, "1", 1);
 212                         if (envchanged)
 213                                 *envchanged = 1;
 214                 } else if (!strcmp(cmd, "--icase-pathspecs")) {
 215                         setenv(GIT_ICASE_PATHSPECS_ENVIRONMENT, "1", 1);
 216                         if (envchanged)
 217                                 *envchanged = 1;
 218                 } else if (!strcmp(cmd, "--shallow-file")) {
 219                         (*argv)++;
 220                         (*argc)--;
 221                         set_alternate_shallow_file((*argv)[0], 1);
 222                         if (envchanged)
 223                                 *envchanged = 1;
 224                 } else if (!strcmp(cmd, "-C")) {
 225                         if (*argc < 2) {
 226                                 fprintf(stderr, "No directory given for -C.\n" );
 227                                 usage(git_usage_string);
 228                         }
 229                         if ((*argv)[1][0]) {
 230                                 if (chdir((*argv)[1]))
 231                                         die_errno("Cannot change to '%s'", (*argv)[1]);
 232                                 if (envchanged)
 233                                         *envchanged = 1;
 234                         }
 235                         (*argv)++;
 236                         (*argc)--;
 237                 } else if (!strcmp(cmd, "--list-builtins")) {
 238                         list_builtins();
 239                         exit(0);
 240                 } else {
 241                         fprintf(stderr, "Unknown option: %s\n", cmd);
 242                         usage(git_usage_string);
 243                 }
 244
 245                 (*argv)++;
 246                 (*argc)--;
 247         }
 248         return (*argv) - orig_argv;
 249 }
 250
 251 static int handle_alias(int *argcp, const char ***argv)
 252 {
 253         int envchanged = 0, ret = 0, saved_errno = errno;
 254         int count, option_count;
 255         const char **new_argv;
 256         const char *alias_command;
 257         char *alias_string;
 258         int unused_nongit;
 259
 260         save_env_before_alias();
 261         setup_git_directory_gently(&unused_nongit);
 262
 263         alias_command = (*argv)[0];
 264         alias_string = alias_lookup(alias_command);
 265         if (alias_string) {
 266                 if (alias_string[0] == '!') {
 267                         struct child_process child = CHILD_PROCESS_INIT;
 268
 269                         commit_pager_choice();
 270                         restore_env(1);
 271
 272                         child.use_shell = 1;
 273                         argv_array_push(&child.args, alias_string + 1);
 274                         argv_array_pushv(&child.args, (*argv) + 1);
 275
 276                         ret = run_command(&child);
 277                         if (ret >= 0)   /* normal exit */
 278                                 exit(ret);
 279
 280                         die_errno("While expanding alias '%s': '%s'",
 281                             alias_command, alias_string + 1);
 282                 }
 283                 count = split_cmdline(alias_string, &new_argv);
 284                 if (count < 0)
 285                         die("Bad alias.%s string: %s", alias_command,
 286                             split_cmdline_strerror(count));
 287                 option_count = handle_options(&new_argv, &count, &envchanged);
 288                 if (envchanged)
 289                         die("alias '%s' changes environment variables\n"
 290                                  "You can use '!git' in the alias to do this.",
 291                                  alias_command);
 292                 memmove(new_argv - option_count, new_argv,
 293                                 count * sizeof(char *));
 294                 new_argv -= option_count;
 295
 296                 if (count < 1)
 297                         die("empty alias for %s", alias_command);
 298
 299                 if (!strcmp(alias_command, new_argv[0]))
 300                         die("recursive alias: %s", alias_command);
 301
 302                 trace_argv_printf(new_argv,
 303                                   "trace: alias expansion: %s =>",
 304                                   alias_command);
 305
 306                 REALLOC_ARRAY(new_argv, count + *argcp);
 307                 /* insert after command name */
 308                 memcpy(new_argv + count, *argv + 1, sizeof(char *) * *argcp);
 309
 310                 *argv = new_argv;
 311                 *argcp += count - 1;
 312
 313                 ret = 1;
 314         }
 315
 316         restore_env(0);
 317
 318         errno = saved_errno;
 319
 320         return ret;
 321 }
 322
 323 #define RUN_SETUP               (1<<0)
 324 #define RUN_SETUP_GENTLY        (1<<1)
 325 #define USE_PAGER               (1<<2)
 326 /*
 327  * require working tree to be present -- anything uses this needs
 328  * RUN_SETUP for reading from the configuration file.
 329  */
 330 #define NEED_WORK_TREE          (1<<3)
 331 #define SUPPORT_SUPER_PREFIX    (1<<4)
 332
 333 struct cmd_struct {
 334         const char *cmd;
 335         int (*fn)(int, const char **, const char *);
 336         int option;
 337 };
 338
 339 static int run_builtin(struct cmd_struct *p, int argc, const char **argv)
 340 {
 341         int status, help;
 342         struct stat st;
 343         const char *prefix;
 344
 345         prefix = NULL;
 346         help = argc == 2 && !strcmp(argv[1], "-h");
 347         if (!help) {
 348                 if (p->option & RUN_SETUP)
 349                         prefix = setup_git_directory();
 350                 else if (p->option & RUN_SETUP_GENTLY) {
 351                         int nongit_ok;
 352                         prefix = setup_git_directory_gently(&nongit_ok);
 353                 }
 354
 355                 if (use_pager == -1 && p->option & (RUN_SETUP | RUN_SETUP_GENTLY))
 356                         use_pager = check_pager_config(p->cmd);
 357                 if (use_pager == -1 && p->option & USE_PAGER)
 358                         use_pager = 1;
 359
 360                 if ((p->option & (RUN_SETUP | RUN_SETUP_GENTLY)) &&
 361                     startup_info->have_repository) /* get_git_dir() may set up repo, avoid that */
 362                         trace_repo_setup(prefix);
 363         }
 364         commit_pager_choice();
 365
 366         if (!help && get_super_prefix()) {
 367                 if (!(p->option & SUPPORT_SUPER_PREFIX))
 368                         die("%s doesn't support --super-prefix", p->cmd);
 369         }
 370
 371         if (!help && p->option & NEED_WORK_TREE)
 372                 setup_work_tree();
 373
 374         trace_argv_printf(argv, "trace: built-in: git");
 375
 376         status = p->fn(argc, argv, prefix);
 377         if (status)
 378                 return status;
 379
 380         /* Somebody closed stdout? */
 381         if (fstat(fileno(stdout), &st))
 382                 return 0;
 383         /* Ignore write errors for pipes and sockets.. */
 384         if (S_ISFIFO(st.st_mode) || S_ISSOCK(st.st_mode))
 385                 return 0;
 386
 387         /* Check for ENOSPC and EIO errors.. */
 388         if (fflush(stdout))
 389                 die_errno("write failure on standard output");
 390         if (ferror(stdout))
 391                 die("unknown write failure on standard output");
 392         if (fclose(stdout))
 393                 die_errno("close failed on standard output");
 394         return 0;
 395 }
 396
 397 static struct cmd_struct commands[] = {
 398         { "add", cmd_add, RUN_SETUP | NEED_WORK_TREE },
 399         { "am", cmd_am, RUN_SETUP | NEED_WORK_TREE },
 400         { "annotate", cmd_annotate, RUN_SETUP },
 401         { "apply", cmd_apply, RUN_SETUP_GENTLY },
 402         { "archive", cmd_archive, RUN_SETUP_GENTLY },
 403         { "bisect--helper", cmd_bisect__helper, RUN_SETUP },
 404         { "blame", cmd_blame, RUN_SETUP },
 405         { "branch", cmd_branch, RUN_SETUP },
 406         { "bundle", cmd_bundle, RUN_SETUP_GENTLY },
 407         { "cat-file", cmd_cat_file, RUN_SETUP },
 408         { "check-attr", cmd_check_attr, RUN_SETUP },
 409         { "check-ignore", cmd_check_ignore, RUN_SETUP | NEED_WORK_TREE },
 410         { "check-mailmap", cmd_check_mailmap, RUN_SETUP },
 411         { "check-ref-format", cmd_check_ref_format },
 412         { "checkout", cmd_checkout, RUN_SETUP | NEED_WORK_TREE },
 413         { "checkout-index", cmd_checkout_index,
 414                 RUN_SETUP | NEED_WORK_TREE},
 415         { "cherry", cmd_cherry, RUN_SETUP },
 416         { "cherry-pick", cmd_cherry_pick, RUN_SETUP | NEED_WORK_TREE },
 417         { "clean", cmd_clean, RUN_SETUP | NEED_WORK_TREE },
 418         { "clone", cmd_clone },
 419         { "column", cmd_column, RUN_SETUP_GENTLY },
 420         { "commit", cmd_commit, RUN_SETUP | NEED_WORK_TREE },
 421         { "commit-tree", cmd_commit_tree, RUN_SETUP },
 422         { "config", cmd_config, RUN_SETUP_GENTLY },
 423         { "count-objects", cmd_count_objects, RUN_SETUP },
 424         { "credential", cmd_credential, RUN_SETUP_GENTLY },
 425         { "describe", cmd_describe, RUN_SETUP },
 426         { "diff", cmd_diff },
 427         { "diff-files", cmd_diff_files, RUN_SETUP | NEED_WORK_TREE },
 428         { "diff-index", cmd_diff_index, RUN_SETUP },
 429         { "diff-tree", cmd_diff_tree, RUN_SETUP },
 430         { "difftool", cmd_difftool, RUN_SETUP | NEED_WORK_TREE },
 431         { "fast-export", cmd_fast_export, RUN_SETUP },
 432         { "fetch", cmd_fetch, RUN_SETUP },
 433         { "fetch-pack", cmd_fetch_pack, RUN_SETUP },
 434         { "fmt-merge-msg", cmd_fmt_merge_msg, RUN_SETUP },
 435         { "for-each-ref", cmd_for_each_ref, RUN_SETUP },
 436         { "format-patch", cmd_format_patch, RUN_SETUP },
 437         { "fsck", cmd_fsck, RUN_SETUP },
 438         { "fsck-objects", cmd_fsck, RUN_SETUP },
 439         { "gc", cmd_gc, RUN_SETUP },
 440         { "get-tar-commit-id", cmd_get_tar_commit_id },
 441         { "grep", cmd_grep, RUN_SETUP_GENTLY | SUPPORT_SUPER_PREFIX },
 442         { "hash-object", cmd_hash_object },
 443         { "help", cmd_help },
 444         { "index-pack", cmd_index_pack, RUN_SETUP_GENTLY },
 445         { "init", cmd_init_db },
 446         { "init-db", cmd_init_db },
 447         { "interpret-trailers", cmd_interpret_trailers, RUN_SETUP_GENTLY },
 448         { "log", cmd_log, RUN_SETUP },
 449         { "ls-files", cmd_ls_files, RUN_SETUP | SUPPORT_SUPER_PREFIX },
 450         { "ls-remote", cmd_ls_remote, RUN_SETUP_GENTLY },
 451         { "ls-tree", cmd_ls_tree, RUN_SETUP },
 452         { "mailinfo", cmd_mailinfo, RUN_SETUP_GENTLY },
 453         { "mailsplit", cmd_mailsplit },
 454         { "merge", cmd_merge, RUN_SETUP | NEED_WORK_TREE },
 455         { "merge-base", cmd_merge_base, RUN_SETUP },
 456         { "merge-file", cmd_merge_file, RUN_SETUP_GENTLY },
 457         { "merge-index", cmd_merge_index, RUN_SETUP },
 458         { "merge-ours", cmd_merge_ours, RUN_SETUP },
 459         { "merge-recursive", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE },
 460         { "merge-recursive-ours", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE },
 461         { "merge-recursive-theirs", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE },
 462         { "merge-subtree", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE },
 463         { "merge-tree", cmd_merge_tree, RUN_SETUP },
 464         { "mktag", cmd_mktag, RUN_SETUP },
 465         { "mktree", cmd_mktree, RUN_SETUP },
 466         { "mv", cmd_mv, RUN_SETUP | NEED_WORK_TREE },
 467         { "name-rev", cmd_name_rev, RUN_SETUP },
 468         { "notes", cmd_notes, RUN_SETUP },
 469         { "pack-objects", cmd_pack_objects, RUN_SETUP },
 470         { "pack-redundant", cmd_pack_redundant, RUN_SETUP },
 471         { "pack-refs", cmd_pack_refs, RUN_SETUP },
 472         { "patch-id", cmd_patch_id, RUN_SETUP_GENTLY },
 473         { "pickaxe", cmd_blame, RUN_SETUP },
 474         { "prune", cmd_prune, RUN_SETUP },
 475         { "prune-packed", cmd_prune_packed, RUN_SETUP },
 476         { "pull", cmd_pull, RUN_SETUP | NEED_WORK_TREE },
 477         { "push", cmd_push, RUN_SETUP },
 478         { "read-tree", cmd_read_tree, RUN_SETUP | SUPPORT_SUPER_PREFIX},
 479         { "rebase--helper", cmd_rebase__helper, RUN_SETUP | NEED_WORK_TREE },
 480         { "receive-pack", cmd_receive_pack },
 481         { "reflog", cmd_reflog, RUN_SETUP },
 482         { "remote", cmd_remote, RUN_SETUP },
 483         { "remote-ext", cmd_remote_ext },
 484         { "remote-fd", cmd_remote_fd },
 485         { "repack", cmd_repack, RUN_SETUP },
 486         { "replace", cmd_replace, RUN_SETUP },
 487         { "rerere", cmd_rerere, RUN_SETUP },
 488         { "reset", cmd_reset, RUN_SETUP },
 489         { "rev-list", cmd_rev_list, RUN_SETUP },
 490         { "rev-parse", cmd_rev_parse },
 491         { "revert", cmd_revert, RUN_SETUP | NEED_WORK_TREE },
 492         { "rm", cmd_rm, RUN_SETUP },
 493         { "send-pack", cmd_send_pack, RUN_SETUP },
 494         { "shortlog", cmd_shortlog, RUN_SETUP_GENTLY | USE_PAGER },
 495         { "show", cmd_show, RUN_SETUP },
 496         { "show-branch", cmd_show_branch, RUN_SETUP },
 497         { "show-ref", cmd_show_ref, RUN_SETUP },
 498         { "stage", cmd_add, RUN_SETUP | NEED_WORK_TREE },
 499         { "status", cmd_status, RUN_SETUP | NEED_WORK_TREE },
 500         { "stripspace", cmd_stripspace },
 501         { "submodule--helper", cmd_submodule__helper, RUN_SETUP | SUPPORT_SUPER_PREFIX},
 502         { "symbolic-ref", cmd_symbolic_ref, RUN_SETUP },
 503         { "tag", cmd_tag, RUN_SETUP },
 504         { "unpack-file", cmd_unpack_file, RUN_SETUP },
 505         { "unpack-objects", cmd_unpack_objects, RUN_SETUP },
 506         { "update-index", cmd_update_index, RUN_SETUP },
 507         { "update-ref", cmd_update_ref, RUN_SETUP },
 508         { "update-server-info", cmd_update_server_info, RUN_SETUP },
 509         { "upload-archive", cmd_upload_archive },
 510         { "upload-archive--writer", cmd_upload_archive_writer },
 511         { "var", cmd_var, RUN_SETUP_GENTLY },
 512         { "verify-commit", cmd_verify_commit, RUN_SETUP },
 513         { "verify-pack", cmd_verify_pack },
 514         { "verify-tag", cmd_verify_tag, RUN_SETUP },
 515         { "version", cmd_version },
 516         { "whatchanged", cmd_whatchanged, RUN_SETUP },
 517         { "worktree", cmd_worktree, RUN_SETUP },
 518         { "write-tree", cmd_write_tree, RUN_SETUP },
 519 };
 520
 521 static struct cmd_struct *get_builtin(const char *s)
 522 {
 523         int i;
 524         for (i = 0; i < ARRAY_SIZE(commands); i++) {
 525                 struct cmd_struct *p = commands + i;
 526                 if (!strcmp(s, p->cmd))
 527                         return p;
 528         }
 529         return NULL;
 530 }
 531
 532 int is_builtin(const char *s)
 533 {
 534         return !!get_builtin(s);
 535 }
 536
 537 static void list_builtins(void)
 538 {
 539         int i;
 540         for (i = 0; i < ARRAY_SIZE(commands); i++)
 541                 printf("%s\n", commands[i].cmd);
 542 }
 543
 544 #ifdef STRIP_EXTENSION
 545 static void strip_extension(const char **argv)
 546 {
 547         size_t len;
 548
 549         if (strip_suffix(argv[0], STRIP_EXTENSION, &len))
 550                 argv[0] = xmemdupz(argv[0], len);
 551 }
 552 #else
 553 #define strip_extension(cmd)
 554 #endif
 555
 556 static void handle_builtin(int argc, const char **argv)
 557 {
 558         struct argv_array args = ARGV_ARRAY_INIT;
 559         const char *cmd;
 560         struct cmd_struct *builtin;
 561
 562         strip_extension(argv);
 563         cmd = argv[0];
 564
 565         /* Turn "git cmd --help" into "git help --exclude-guides cmd" */
 566         if (argc > 1 && !strcmp(argv[1], "--help")) {
 567                 int i;
 568
 569                 argv[1] = argv[0];
 570                 argv[0] = cmd = "help";
 571
 572                 for (i = 0; i < argc; i++) {
 573                         argv_array_push(&args, argv[i]);
 574                         if (!i)
 575                                 argv_array_push(&args, "--exclude-guides");
 576                 }
 577
 578                 argc++;
 579                 argv = args.argv;
 580         }
 581
 582         builtin = get_builtin(cmd);
 583         if (builtin)
 584                 exit(run_builtin(builtin, argc, argv));
 585         argv_array_clear(&args);
 586 }
 587
 588 static void execv_dashed_external(const char **argv)
 589 {
 590         struct child_process cmd = CHILD_PROCESS_INIT;
 591         int status;
 592
 593         if (get_super_prefix())
 594                 die("%s doesn't support --super-prefix", argv[0]);
 595
 596         if (use_pager == -1)
 597                 use_pager = check_pager_config(argv[0]);
 598         commit_pager_choice();
 599
 600         argv_array_pushf(&cmd.args, "git-%s", argv[0]);
 601         argv_array_pushv(&cmd.args, argv + 1);
 602         cmd.clean_on_exit = 1;
 603         cmd.wait_after_clean = 1;
 604         cmd.silent_exec_failure = 1;
 605
 606         trace_argv_printf(cmd.args.argv, "trace: exec:");
 607
 608         /*
 609          * If we fail because the command is not found, it is
 610          * OK to return. Otherwise, we just pass along the status code,
 611          * or our usual generic code if we were not even able to exec
 612          * the program.
 613          */
 614         status = run_command(&cmd);
 615         if (status >= 0)
 616                 exit(status);
 617         else if (errno != ENOENT)
 618                 exit(128);
 619 }
 620
 621 static int run_argv(int *argcp, const char ***argv)
 622 {
 623         int done_alias = 0;
 624
 625         while (1) {
 626                 /*
 627                  * If we tried alias and futzed with our environment,
 628                  * it no longer is safe to invoke builtins directly in
 629                  * general.  We have to spawn them as dashed externals.
 630                  *
 631                  * NEEDSWORK: if we can figure out cases
 632                  * where it is safe to do, we can avoid spawning a new
 633                  * process.
 634                  */
 635                 if (!done_alias)
 636                         handle_builtin(*argcp, *argv);
 637
 638                 /* .. then try the external ones */
 639                 execv_dashed_external(*argv);
 640
 641                 /* It could be an alias -- this works around the insanity
 642                  * of overriding "git log" with "git show" by having
 643                  * alias.log = show
 644                  */
 645                 if (done_alias)
 646                         break;
 647                 if (!handle_alias(argcp, argv))
 648                         break;
 649                 done_alias = 1;
 650         }
 651
 652         return done_alias;
 653 }
 654
 655 int cmd_main(int argc, const char **argv)
 656 {
 657         const char *cmd;
 658         int done_help = 0;
 659
 660         cmd = argv[0];
 661         if (!cmd)
 662                 cmd = "git-help";
 663         else {
 664                 const char *slash = find_last_dir_sep(cmd);
 665                 if (slash)
 666                         cmd = slash + 1;
 667         }
 668
 669         trace_command_performance(argv);
 670
 671         /*
 672          * "git-xxxx" is the same as "git xxxx", but we obviously:
 673          *
 674          *  - cannot take flags in between the "git" and the "xxxx".
 675          *  - cannot execute it externally (since it would just do
 676          *    the same thing over again)
 677          *
 678          * So we just directly call the builtin handler, and die if
 679          * that one cannot handle it.
 680          */
 681         if (skip_prefix(cmd, "git-", &cmd)) {
 682                 argv[0] = cmd;
 683                 handle_builtin(argc, argv);
 684                 die("cannot handle %s as a builtin", cmd);
 685         }
 686
 687         /* Look for flags.. */
 688         argv++;
 689         argc--;
 690         handle_options(&argv, &argc, NULL);
 691         if (argc > 0) {
 692                 /* translate --help and --version into commands */
 693                 skip_prefix(argv[0], "--", &argv[0]);
 694         } else {
 695                 /* The user didn't specify a command; give them help */
 696                 commit_pager_choice();
 697                 printf("usage: %s\n\n", git_usage_string);
 698                 list_common_cmds_help();
 699                 printf("\n%s\n", _(git_more_info_string));
 700                 exit(1);
 701         }
 702         cmd = argv[0];
 703
 704         /*
 705          * We use PATH to find git commands, but we prepend some higher
 706          * precedence paths: the "--exec-path" option, the GIT_EXEC_PATH
 707          * environment, and the $(gitexecdir) from the Makefile at build
 708          * time.
 709          */
 710         setup_path();
 711
 712         while (1) {
 713                 int was_alias = run_argv(&argc, &argv);
 714                 if (errno != ENOENT)
 715                         break;
 716                 if (was_alias) {
 717                         fprintf(stderr, "Expansion of alias '%s' failed; "
 718                                 "'%s' is not a git command\n",
 719                                 cmd, argv[0]);
 720                         exit(1);
 721                 }
 722                 if (!done_help) {
 723                         cmd = argv[0] = help_unknown_cmd(cmd);
 724                         done_help = 1;
 725                 } else
 726                         break;
 727         }
 728
 729         fprintf(stderr, "Failed to run command '%s': %s\n",
 730                 cmd, strerror(errno));
 731
 732         return 1;
 733 }