git.c

   1 #include "builtin.h"
   2 #include "config.h"
   3 #include "environment.h"
   4 #include "exec-cmd.h"
   5 #include "gettext.h"
   6 #include "help.h"
   7 #include "object-file.h"
   8 #include "pager.h"
   9 #include "read-cache-ll.h"
  10 #include "run-command.h"
  11 #include "alias.h"
  12 #include "replace-object.h"
  13 #include "setup.h"
  14 #include "attr.h"
  15 #include "shallow.h"
  16 #include "trace.h"
  17 #include "trace2.h"
  18
  19 #define RUN_SETUP               (1<<0)
  20 #define RUN_SETUP_GENTLY        (1<<1)
  21 #define USE_PAGER               (1<<2)
  22 /*
  23  * require working tree to be present -- anything uses this needs
  24  * RUN_SETUP for reading from the configuration file.
  25  */
  26 #define NEED_WORK_TREE          (1<<3)
  27 #define DELAY_PAGER_CONFIG      (1<<4)
  28 #define NO_PARSEOPT             (1<<5) /* parse-options is not used */
  29
  30 struct cmd_struct {
  31         const char *cmd;
  32         int (*fn)(int, const char **, const char *);
  33         unsigned int option;
  34 };
  35
  36 const char git_usage_string[] =
  37         N_("git [-v | --version] [-h | --help] [-C <path>] [-c <name>=<value>]\n"
  38            "           [--exec-path[=<path>]] [--html-path] [--man-path] [--info-path]\n"
  39            "           [-p | --paginate | -P | --no-pager] [--no-replace-objects] [--bare]\n"
  40            "           [--git-dir=<path>] [--work-tree=<path>] [--namespace=<name>]\n"
  41            "           [--config-env=<name>=<envvar>] <command> [<args>]");
  42
  43 const char git_more_info_string[] =
  44         N_("'git help -a' and 'git help -g' list available subcommands and some\n"
  45            "concept guides. See 'git help <command>' or 'git help <concept>'\n"
  46            "to read about a specific subcommand or concept.\n"
  47            "See 'git help git' for an overview of the system.");
  48
  49 static int use_pager = -1;
  50
  51 static void list_builtins(struct string_list *list, unsigned int exclude_option);
  52
  53 static void exclude_helpers_from_list(struct string_list *list)
  54 {
  55         int i = 0;
  56
  57         while (i < list->nr) {
  58                 if (strstr(list->items[i].string, "--"))
  59                         unsorted_string_list_delete_item(list, i, 0);
  60                 else
  61                         i++;
  62         }
  63 }
  64
  65 static int match_token(const char *spec, int len, const char *token)
  66 {
  67         int token_len = strlen(token);
  68
  69         return len == token_len && !strncmp(spec, token, token_len);
  70 }
  71
  72 static int list_cmds(const char *spec)
  73 {
  74         struct string_list list = STRING_LIST_INIT_DUP;
  75         int i;
  76         int nongit;
  77
  78         /*
  79         * Set up the repository so we can pick up any repo-level config (like
  80         * completion.commands).
  81         */
  82         setup_git_directory_gently(&nongit);
  83
  84         while (*spec) {
  85                 const char *sep = strchrnul(spec, ',');
  86                 int len = sep - spec;
  87
  88                 if (match_token(spec, len, "builtins"))
  89                         list_builtins(&list, 0);
  90                 else if (match_token(spec, len, "main"))
  91                         list_all_main_cmds(&list);
  92                 else if (match_token(spec, len, "others"))
  93                         list_all_other_cmds(&list);
  94                 else if (match_token(spec, len, "nohelpers"))
  95                         exclude_helpers_from_list(&list);
  96                 else if (match_token(spec, len, "alias"))
  97                         list_aliases(&list);
  98                 else if (match_token(spec, len, "config"))
  99                         list_cmds_by_config(&list);
 100                 else if (len > 5 && !strncmp(spec, "list-", 5)) {
 101                         struct strbuf sb = STRBUF_INIT;
 102
 103                         strbuf_add(&sb, spec + 5, len - 5);
 104                         list_cmds_by_category(&list, sb.buf);
 105                         strbuf_release(&sb);
 106                 }
 107                 else
 108                         die(_("unsupported command listing type '%s'"), spec);
 109                 spec += len;
 110                 if (*spec == ',')
 111                         spec++;
 112         }
 113         for (i = 0; i < list.nr; i++)
 114                 puts(list.items[i].string);
 115         string_list_clear(&list, 0);
 116         return 0;
 117 }
 118
 119 static void commit_pager_choice(void)
 120 {
 121         switch (use_pager) {
 122         case 0:
 123                 setenv("GIT_PAGER", "cat", 1);
 124                 break;
 125         case 1:
 126                 setup_pager();
 127                 break;
 128         default:
 129                 break;
 130         }
 131 }
 132
 133 void setup_auto_pager(const char *cmd, int def)
 134 {
 135         if (use_pager != -1 || pager_in_use())
 136                 return;
 137         use_pager = check_pager_config(cmd);
 138         if (use_pager == -1)
 139                 use_pager = def;
 140         commit_pager_choice();
 141 }
 142
 143 static int handle_options(const char ***argv, int *argc, int *envchanged)
 144 {
 145         const char **orig_argv = *argv;
 146
 147         while (*argc > 0) {
 148                 const char *cmd = (*argv)[0];
 149                 if (cmd[0] != '-')
 150                         break;
 151
 152                 /*
 153                  * For legacy reasons, the "version" and "help"
 154                  * commands can be written with "--" prepended
 155                  * to make them look like flags.
 156                  */
 157                 if (!strcmp(cmd, "--help") || !strcmp(cmd, "-h") ||
 158                     !strcmp(cmd, "--version") || !strcmp(cmd, "-v"))
 159                         break;
 160
 161                 /*
 162                  * Check remaining flags.
 163                  */
 164                 if (skip_prefix(cmd, "--exec-path", &cmd)) {
 165                         if (*cmd == '=')
 166                                 git_set_exec_path(cmd + 1);
 167                         else {
 168                                 puts(git_exec_path());
 169                                 trace2_cmd_name("_query_");
 170                                 exit(0);
 171                         }
 172                 } else if (!strcmp(cmd, "--html-path")) {
 173                         puts(system_path(GIT_HTML_PATH));
 174                         trace2_cmd_name("_query_");
 175                         exit(0);
 176                 } else if (!strcmp(cmd, "--man-path")) {
 177                         puts(system_path(GIT_MAN_PATH));
 178                         trace2_cmd_name("_query_");
 179                         exit(0);
 180                 } else if (!strcmp(cmd, "--info-path")) {
 181                         puts(system_path(GIT_INFO_PATH));
 182                         trace2_cmd_name("_query_");
 183                         exit(0);
 184                 } else if (!strcmp(cmd, "-p") || !strcmp(cmd, "--paginate")) {
 185                         use_pager = 1;
 186                 } else if (!strcmp(cmd, "-P") || !strcmp(cmd, "--no-pager")) {
 187                         use_pager = 0;
 188                         if (envchanged)
 189                                 *envchanged = 1;
 190                 } else if (!strcmp(cmd, "--no-lazy-fetch")) {
 191                         fetch_if_missing = 0;
 192                         setenv(NO_LAZY_FETCH_ENVIRONMENT, "1", 1);
 193                         if (envchanged)
 194                                 *envchanged = 1;
 195                 } else if (!strcmp(cmd, "--no-replace-objects")) {
 196                         disable_replace_refs();
 197                         setenv(NO_REPLACE_OBJECTS_ENVIRONMENT, "1", 1);
 198                         if (envchanged)
 199                                 *envchanged = 1;
 200                 } else if (!strcmp(cmd, "--git-dir")) {
 201                         if (*argc < 2) {
 202                                 fprintf(stderr, _("no directory given for '%s' option\n" ), "--git-dir");
 203                                 usage(git_usage_string);
 204                         }
 205                         setenv(GIT_DIR_ENVIRONMENT, (*argv)[1], 1);
 206                         if (envchanged)
 207                                 *envchanged = 1;
 208                         (*argv)++;
 209                         (*argc)--;
 210                 } else if (skip_prefix(cmd, "--git-dir=", &cmd)) {
 211                         setenv(GIT_DIR_ENVIRONMENT, cmd, 1);
 212                         if (envchanged)
 213                                 *envchanged = 1;
 214                 } else if (!strcmp(cmd, "--namespace")) {
 215                         if (*argc < 2) {
 216                                 fprintf(stderr, _("no namespace given for --namespace\n" ));
 217                                 usage(git_usage_string);
 218                         }
 219                         setenv(GIT_NAMESPACE_ENVIRONMENT, (*argv)[1], 1);
 220                         if (envchanged)
 221                                 *envchanged = 1;
 222                         (*argv)++;
 223                         (*argc)--;
 224                 } else if (skip_prefix(cmd, "--namespace=", &cmd)) {
 225                         setenv(GIT_NAMESPACE_ENVIRONMENT, cmd, 1);
 226                         if (envchanged)
 227                                 *envchanged = 1;
 228                 } else if (!strcmp(cmd, "--work-tree")) {
 229                         if (*argc < 2) {
 230                                 fprintf(stderr, _("no directory given for '%s' option\n" ), "--work-tree");
 231                                 usage(git_usage_string);
 232                         }
 233                         setenv(GIT_WORK_TREE_ENVIRONMENT, (*argv)[1], 1);
 234                         if (envchanged)
 235                                 *envchanged = 1;
 236                         (*argv)++;
 237                         (*argc)--;
 238                 } else if (skip_prefix(cmd, "--work-tree=", &cmd)) {
 239                         setenv(GIT_WORK_TREE_ENVIRONMENT, cmd, 1);
 240                         if (envchanged)
 241                                 *envchanged = 1;
 242                 } else if (!strcmp(cmd, "--bare")) {
 243                         char *cwd = xgetcwd();
 244                         is_bare_repository_cfg = 1;
 245                         setenv(GIT_DIR_ENVIRONMENT, cwd, 0);
 246                         free(cwd);
 247                         setenv(GIT_IMPLICIT_WORK_TREE_ENVIRONMENT, "0", 1);
 248                         if (envchanged)
 249                                 *envchanged = 1;
 250                 } else if (!strcmp(cmd, "-c")) {
 251                         if (*argc < 2) {
 252                                 fprintf(stderr, _("-c expects a configuration string\n" ));
 253                                 usage(git_usage_string);
 254                         }
 255                         git_config_push_parameter((*argv)[1]);
 256                         (*argv)++;
 257                         (*argc)--;
 258                 } else if (!strcmp(cmd, "--config-env")) {
 259                         if (*argc < 2) {
 260                                 fprintf(stderr, _("no config key given for --config-env\n" ));
 261                                 usage(git_usage_string);
 262                         }
 263                         git_config_push_env((*argv)[1]);
 264                         (*argv)++;
 265                         (*argc)--;
 266                 } else if (skip_prefix(cmd, "--config-env=", &cmd)) {
 267                         git_config_push_env(cmd);
 268                 } else if (!strcmp(cmd, "--literal-pathspecs")) {
 269                         setenv(GIT_LITERAL_PATHSPECS_ENVIRONMENT, "1", 1);
 270                         if (envchanged)
 271                                 *envchanged = 1;
 272                 } else if (!strcmp(cmd, "--no-literal-pathspecs")) {
 273                         setenv(GIT_LITERAL_PATHSPECS_ENVIRONMENT, "0", 1);
 274                         if (envchanged)
 275                                 *envchanged = 1;
 276                 } else if (!strcmp(cmd, "--glob-pathspecs")) {
 277                         setenv(GIT_GLOB_PATHSPECS_ENVIRONMENT, "1", 1);
 278                         if (envchanged)
 279                                 *envchanged = 1;
 280                 } else if (!strcmp(cmd, "--noglob-pathspecs")) {
 281                         setenv(GIT_NOGLOB_PATHSPECS_ENVIRONMENT, "1", 1);
 282                         if (envchanged)
 283                                 *envchanged = 1;
 284                 } else if (!strcmp(cmd, "--icase-pathspecs")) {
 285                         setenv(GIT_ICASE_PATHSPECS_ENVIRONMENT, "1", 1);
 286                         if (envchanged)
 287                                 *envchanged = 1;
 288                 } else if (!strcmp(cmd, "--no-optional-locks")) {
 289                         setenv(GIT_OPTIONAL_LOCKS_ENVIRONMENT, "0", 1);
 290                         if (envchanged)
 291                                 *envchanged = 1;
 292                 } else if (!strcmp(cmd, "--shallow-file")) {
 293                         (*argv)++;
 294                         (*argc)--;
 295                         set_alternate_shallow_file(the_repository, (*argv)[0], 1);
 296                         if (envchanged)
 297                                 *envchanged = 1;
 298                 } else if (!strcmp(cmd, "-C")) {
 299                         if (*argc < 2) {
 300                                 fprintf(stderr, _("no directory given for '%s' option\n" ), "-C");
 301                                 usage(git_usage_string);
 302                         }
 303                         if ((*argv)[1][0]) {
 304                                 if (chdir((*argv)[1]))
 305                                         die_errno("cannot change to '%s'", (*argv)[1]);
 306                                 if (envchanged)
 307                                         *envchanged = 1;
 308                         }
 309                         (*argv)++;
 310                         (*argc)--;
 311                 } else if (skip_prefix(cmd, "--list-cmds=", &cmd)) {
 312                         trace2_cmd_name("_query_");
 313                         if (!strcmp(cmd, "parseopt")) {
 314                                 struct string_list list = STRING_LIST_INIT_DUP;
 315                                 int i;
 316
 317                                 list_builtins(&list, NO_PARSEOPT);
 318                                 for (i = 0; i < list.nr; i++)
 319                                         printf("%s ", list.items[i].string);
 320                                 string_list_clear(&list, 0);
 321                                 exit(0);
 322                         } else {
 323                                 exit(list_cmds(cmd));
 324                         }
 325                 } else if (!strcmp(cmd, "--attr-source")) {
 326                         if (*argc < 2) {
 327                                 fprintf(stderr, _("no attribute source given for --attr-source\n" ));
 328                                 usage(git_usage_string);
 329                         }
 330                         setenv(GIT_ATTR_SOURCE_ENVIRONMENT, (*argv)[1], 1);
 331                         if (envchanged)
 332                                 *envchanged = 1;
 333                         (*argv)++;
 334                         (*argc)--;
 335                 } else if (skip_prefix(cmd, "--attr-source=", &cmd)) {
 336                         set_git_attr_source(cmd);
 337                         setenv(GIT_ATTR_SOURCE_ENVIRONMENT, cmd, 1);
 338                         if (envchanged)
 339                                 *envchanged = 1;
 340                 } else {
 341                         fprintf(stderr, _("unknown option: %s\n"), cmd);
 342                         usage(git_usage_string);
 343                 }
 344
 345                 (*argv)++;
 346                 (*argc)--;
 347         }
 348         return (*argv) - orig_argv;
 349 }
 350
 351 static int handle_alias(int *argcp, const char ***argv)
 352 {
 353         int envchanged = 0, ret = 0, saved_errno = errno;
 354         int count, option_count;
 355         const char **new_argv;
 356         const char *alias_command;
 357         char *alias_string;
 358
 359         alias_command = (*argv)[0];
 360         alias_string = alias_lookup(alias_command);
 361         if (alias_string) {
 362                 if (*argcp > 1 && !strcmp((*argv)[1], "-h"))
 363                         fprintf_ln(stderr, _("'%s' is aliased to '%s'"),
 364                                    alias_command, alias_string);
 365                 if (alias_string[0] == '!') {
 366                         struct child_process child = CHILD_PROCESS_INIT;
 367                         int nongit_ok;
 368
 369                         /* Aliases expect GIT_PREFIX, GIT_DIR etc to be set */
 370                         setup_git_directory_gently(&nongit_ok);
 371
 372                         commit_pager_choice();
 373
 374                         child.use_shell = 1;
 375                         child.clean_on_exit = 1;
 376                         child.wait_after_clean = 1;
 377                         child.trace2_child_class = "shell_alias";
 378                         strvec_push(&child.args, alias_string + 1);
 379                         strvec_pushv(&child.args, (*argv) + 1);
 380
 381                         trace2_cmd_alias(alias_command, child.args.v);
 382                         trace2_cmd_list_config();
 383                         trace2_cmd_list_env_vars();
 384                         trace2_cmd_name("_run_shell_alias_");
 385
 386                         ret = run_command(&child);
 387                         if (ret >= 0)   /* normal exit */
 388                                 exit(ret);
 389
 390                         die_errno(_("while expanding alias '%s': '%s'"),
 391                                   alias_command, alias_string + 1);
 392                 }
 393                 count = split_cmdline(alias_string, &new_argv);
 394                 if (count < 0)
 395                         die(_("bad alias.%s string: %s"), alias_command,
 396                             _(split_cmdline_strerror(count)));
 397                 option_count = handle_options(&new_argv, &count, &envchanged);
 398                 if (envchanged)
 399                         die(_("alias '%s' changes environment variables.\n"
 400                               "You can use '!git' in the alias to do this"),
 401                             alias_command);
 402                 MOVE_ARRAY(new_argv - option_count, new_argv, count);
 403                 new_argv -= option_count;
 404
 405                 if (count < 1)
 406                         die(_("empty alias for %s"), alias_command);
 407
 408                 if (!strcmp(alias_command, new_argv[0]))
 409                         die(_("recursive alias: %s"), alias_command);
 410
 411                 trace_argv_printf(new_argv,
 412                                   "trace: alias expansion: %s =>",
 413                                   alias_command);
 414
 415                 REALLOC_ARRAY(new_argv, count + *argcp);
 416                 /* insert after command name */
 417                 COPY_ARRAY(new_argv + count, *argv + 1, *argcp);
 418
 419                 trace2_cmd_alias(alias_command, new_argv);
 420                 trace2_cmd_list_config();
 421                 trace2_cmd_list_env_vars();
 422
 423                 *argv = new_argv;
 424                 *argcp += count - 1;
 425
 426                 ret = 1;
 427         }
 428
 429         errno = saved_errno;
 430
 431         return ret;
 432 }
 433
 434 static int run_builtin(struct cmd_struct *p, int argc, const char **argv)
 435 {
 436         int status, help;
 437         struct stat st;
 438         const char *prefix;
 439         int run_setup = (p->option & (RUN_SETUP | RUN_SETUP_GENTLY));
 440
 441         help = argc == 2 && !strcmp(argv[1], "-h");
 442         if (help && (run_setup & RUN_SETUP))
 443                 /* demote to GENTLY to allow 'git cmd -h' outside repo */
 444                 run_setup = RUN_SETUP_GENTLY;
 445
 446         if (run_setup & RUN_SETUP) {
 447                 prefix = setup_git_directory();
 448         } else if (run_setup & RUN_SETUP_GENTLY) {
 449                 int nongit_ok;
 450                 prefix = setup_git_directory_gently(&nongit_ok);
 451         } else {
 452                 prefix = NULL;
 453         }
 454         assert(!prefix || *prefix);
 455         precompose_argv_prefix(argc, argv, NULL);
 456         if (use_pager == -1 && run_setup &&
 457                 !(p->option & DELAY_PAGER_CONFIG))
 458                 use_pager = check_pager_config(p->cmd);
 459         if (use_pager == -1 && p->option & USE_PAGER)
 460                 use_pager = 1;
 461         if (run_setup && startup_info->have_repository)
 462                 /* get_git_dir() may set up repo, avoid that */
 463                 trace_repo_setup();
 464         commit_pager_choice();
 465
 466         if (!help && p->option & NEED_WORK_TREE)
 467                 setup_work_tree();
 468
 469         trace_argv_printf(argv, "trace: built-in: git");
 470         trace2_cmd_name(p->cmd);
 471         trace2_cmd_list_config();
 472         trace2_cmd_list_env_vars();
 473
 474         validate_cache_entries(the_repository->index);
 475         status = p->fn(argc, argv, prefix);
 476         validate_cache_entries(the_repository->index);
 477
 478         if (status)
 479                 return status;
 480
 481         /* Somebody closed stdout? */
 482         if (fstat(fileno(stdout), &st))
 483                 return 0;
 484         /* Ignore write errors for pipes and sockets.. */
 485         if (S_ISFIFO(st.st_mode) || S_ISSOCK(st.st_mode))
 486                 return 0;
 487
 488         /* Check for ENOSPC and EIO errors.. */
 489         if (fflush(stdout))
 490                 die_errno(_("write failure on standard output"));
 491         if (ferror(stdout))
 492                 die(_("unknown write failure on standard output"));
 493         if (fclose(stdout))
 494                 die_errno(_("close failed on standard output"));
 495         return 0;
 496 }
 497
 498 static struct cmd_struct commands[] = {
 499         { "add", cmd_add, RUN_SETUP | NEED_WORK_TREE },
 500         { "am", cmd_am, RUN_SETUP | NEED_WORK_TREE },
 501         { "annotate", cmd_annotate, RUN_SETUP },
 502         { "apply", cmd_apply, RUN_SETUP_GENTLY },
 503         { "archive", cmd_archive, RUN_SETUP_GENTLY },
 504         { "bisect", cmd_bisect, RUN_SETUP },
 505         { "blame", cmd_blame, RUN_SETUP },
 506         { "branch", cmd_branch, RUN_SETUP | DELAY_PAGER_CONFIG },
 507         { "bugreport", cmd_bugreport, RUN_SETUP_GENTLY },
 508         { "bundle", cmd_bundle, RUN_SETUP_GENTLY },
 509         { "cat-file", cmd_cat_file, RUN_SETUP },
 510         { "check-attr", cmd_check_attr, RUN_SETUP },
 511         { "check-ignore", cmd_check_ignore, RUN_SETUP | NEED_WORK_TREE },
 512         { "check-mailmap", cmd_check_mailmap, RUN_SETUP },
 513         { "check-ref-format", cmd_check_ref_format, NO_PARSEOPT  },
 514         { "checkout", cmd_checkout, RUN_SETUP | NEED_WORK_TREE },
 515         { "checkout--worker", cmd_checkout__worker,
 516                 RUN_SETUP | NEED_WORK_TREE },
 517         { "checkout-index", cmd_checkout_index,
 518                 RUN_SETUP | NEED_WORK_TREE},
 519         { "cherry", cmd_cherry, RUN_SETUP },
 520         { "cherry-pick", cmd_cherry_pick, RUN_SETUP | NEED_WORK_TREE },
 521         { "clean", cmd_clean, RUN_SETUP | NEED_WORK_TREE },
 522         { "clone", cmd_clone },
 523         { "column", cmd_column, RUN_SETUP_GENTLY },
 524         { "commit", cmd_commit, RUN_SETUP | NEED_WORK_TREE },
 525         { "commit-graph", cmd_commit_graph, RUN_SETUP },
 526         { "commit-tree", cmd_commit_tree, RUN_SETUP },
 527         { "config", cmd_config, RUN_SETUP_GENTLY | DELAY_PAGER_CONFIG },
 528         { "count-objects", cmd_count_objects, RUN_SETUP },
 529         { "credential", cmd_credential, RUN_SETUP_GENTLY | NO_PARSEOPT },
 530         { "credential-cache", cmd_credential_cache },
 531         { "credential-cache--daemon", cmd_credential_cache_daemon },
 532         { "credential-store", cmd_credential_store },
 533         { "describe", cmd_describe, RUN_SETUP },
 534         { "diagnose", cmd_diagnose, RUN_SETUP_GENTLY },
 535         { "diff", cmd_diff, NO_PARSEOPT },
 536         { "diff-files", cmd_diff_files, RUN_SETUP | NEED_WORK_TREE | NO_PARSEOPT },
 537         { "diff-index", cmd_diff_index, RUN_SETUP | NO_PARSEOPT },
 538         { "diff-tree", cmd_diff_tree, RUN_SETUP | NO_PARSEOPT },
 539         { "difftool", cmd_difftool, RUN_SETUP_GENTLY },
 540         { "fast-export", cmd_fast_export, RUN_SETUP },
 541         { "fast-import", cmd_fast_import, RUN_SETUP | NO_PARSEOPT },
 542         { "fetch", cmd_fetch, RUN_SETUP },
 543         { "fetch-pack", cmd_fetch_pack, RUN_SETUP | NO_PARSEOPT },
 544         { "fmt-merge-msg", cmd_fmt_merge_msg, RUN_SETUP },
 545         { "for-each-ref", cmd_for_each_ref, RUN_SETUP },
 546         { "for-each-repo", cmd_for_each_repo, RUN_SETUP_GENTLY },
 547         { "format-patch", cmd_format_patch, RUN_SETUP },
 548         { "fsck", cmd_fsck, RUN_SETUP },
 549         { "fsck-objects", cmd_fsck, RUN_SETUP },
 550         { "fsmonitor--daemon", cmd_fsmonitor__daemon, RUN_SETUP },
 551         { "gc", cmd_gc, RUN_SETUP },
 552         { "get-tar-commit-id", cmd_get_tar_commit_id, NO_PARSEOPT },
 553         { "grep", cmd_grep, RUN_SETUP_GENTLY },
 554         { "hash-object", cmd_hash_object },
 555         { "help", cmd_help },
 556         { "hook", cmd_hook, RUN_SETUP },
 557         { "index-pack", cmd_index_pack, RUN_SETUP_GENTLY | NO_PARSEOPT },
 558         { "init", cmd_init_db },
 559         { "init-db", cmd_init_db },
 560         { "interpret-trailers", cmd_interpret_trailers, RUN_SETUP_GENTLY },
 561         { "log", cmd_log, RUN_SETUP },
 562         { "ls-files", cmd_ls_files, RUN_SETUP },
 563         { "ls-remote", cmd_ls_remote, RUN_SETUP_GENTLY },
 564         { "ls-tree", cmd_ls_tree, RUN_SETUP },
 565         { "mailinfo", cmd_mailinfo, RUN_SETUP_GENTLY },
 566         { "mailsplit", cmd_mailsplit, NO_PARSEOPT },
 567         { "maintenance", cmd_maintenance, RUN_SETUP },
 568         { "merge", cmd_merge, RUN_SETUP | NEED_WORK_TREE },
 569         { "merge-base", cmd_merge_base, RUN_SETUP },
 570         { "merge-file", cmd_merge_file, RUN_SETUP_GENTLY },
 571         { "merge-index", cmd_merge_index, RUN_SETUP | NO_PARSEOPT },
 572         { "merge-ours", cmd_merge_ours, RUN_SETUP | NO_PARSEOPT },
 573         { "merge-recursive", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE | NO_PARSEOPT },
 574         { "merge-recursive-ours", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE | NO_PARSEOPT },
 575         { "merge-recursive-theirs", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE | NO_PARSEOPT },
 576         { "merge-subtree", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE | NO_PARSEOPT },
 577         { "merge-tree", cmd_merge_tree, RUN_SETUP },
 578         { "mktag", cmd_mktag, RUN_SETUP },
 579         { "mktree", cmd_mktree, RUN_SETUP },
 580         { "multi-pack-index", cmd_multi_pack_index, RUN_SETUP },
 581         { "mv", cmd_mv, RUN_SETUP | NEED_WORK_TREE },
 582         { "name-rev", cmd_name_rev, RUN_SETUP },
 583         { "notes", cmd_notes, RUN_SETUP },
 584         { "pack-objects", cmd_pack_objects, RUN_SETUP },
 585         { "pack-redundant", cmd_pack_redundant, RUN_SETUP | NO_PARSEOPT },
 586         { "pack-refs", cmd_pack_refs, RUN_SETUP },
 587         { "patch-id", cmd_patch_id, RUN_SETUP_GENTLY | NO_PARSEOPT },
 588         { "pickaxe", cmd_blame, RUN_SETUP },
 589         { "prune", cmd_prune, RUN_SETUP },
 590         { "prune-packed", cmd_prune_packed, RUN_SETUP },
 591         { "pull", cmd_pull, RUN_SETUP | NEED_WORK_TREE },
 592         { "push", cmd_push, RUN_SETUP },
 593         { "range-diff", cmd_range_diff, RUN_SETUP | USE_PAGER },
 594         { "read-tree", cmd_read_tree, RUN_SETUP },
 595         { "rebase", cmd_rebase, RUN_SETUP | NEED_WORK_TREE },
 596         { "receive-pack", cmd_receive_pack },
 597         { "reflog", cmd_reflog, RUN_SETUP },
 598         { "remote", cmd_remote, RUN_SETUP },
 599         { "remote-ext", cmd_remote_ext, NO_PARSEOPT },
 600         { "remote-fd", cmd_remote_fd, NO_PARSEOPT },
 601         { "repack", cmd_repack, RUN_SETUP },
 602         { "replace", cmd_replace, RUN_SETUP },
 603         { "replay", cmd_replay, RUN_SETUP },
 604         { "rerere", cmd_rerere, RUN_SETUP },
 605         { "reset", cmd_reset, RUN_SETUP },
 606         { "restore", cmd_restore, RUN_SETUP | NEED_WORK_TREE },
 607         { "rev-list", cmd_rev_list, RUN_SETUP | NO_PARSEOPT },
 608         { "rev-parse", cmd_rev_parse, NO_PARSEOPT },
 609         { "revert", cmd_revert, RUN_SETUP | NEED_WORK_TREE },
 610         { "rm", cmd_rm, RUN_SETUP },
 611         { "send-pack", cmd_send_pack, RUN_SETUP },
 612         { "shortlog", cmd_shortlog, RUN_SETUP_GENTLY | USE_PAGER },
 613         { "show", cmd_show, RUN_SETUP },
 614         { "show-branch", cmd_show_branch, RUN_SETUP },
 615         { "show-index", cmd_show_index, RUN_SETUP_GENTLY },
 616         { "show-ref", cmd_show_ref, RUN_SETUP },
 617         { "sparse-checkout", cmd_sparse_checkout, RUN_SETUP },
 618         { "stage", cmd_add, RUN_SETUP | NEED_WORK_TREE },
 619         { "stash", cmd_stash, RUN_SETUP | NEED_WORK_TREE },
 620         { "status", cmd_status, RUN_SETUP | NEED_WORK_TREE },
 621         { "stripspace", cmd_stripspace },
 622         { "submodule--helper", cmd_submodule__helper, RUN_SETUP },
 623         { "switch", cmd_switch, RUN_SETUP | NEED_WORK_TREE },
 624         { "symbolic-ref", cmd_symbolic_ref, RUN_SETUP },
 625         { "tag", cmd_tag, RUN_SETUP | DELAY_PAGER_CONFIG },
 626         { "unpack-file", cmd_unpack_file, RUN_SETUP | NO_PARSEOPT },
 627         { "unpack-objects", cmd_unpack_objects, RUN_SETUP | NO_PARSEOPT },
 628         { "update-index", cmd_update_index, RUN_SETUP },
 629         { "update-ref", cmd_update_ref, RUN_SETUP },
 630         { "update-server-info", cmd_update_server_info, RUN_SETUP },
 631         { "upload-archive", cmd_upload_archive, NO_PARSEOPT },
 632         { "upload-archive--writer", cmd_upload_archive_writer, NO_PARSEOPT },
 633         { "upload-pack", cmd_upload_pack },
 634         { "var", cmd_var, RUN_SETUP_GENTLY | NO_PARSEOPT },
 635         { "verify-commit", cmd_verify_commit, RUN_SETUP },
 636         { "verify-pack", cmd_verify_pack },
 637         { "verify-tag", cmd_verify_tag, RUN_SETUP },
 638         { "version", cmd_version },
 639         { "whatchanged", cmd_whatchanged, RUN_SETUP },
 640         { "worktree", cmd_worktree, RUN_SETUP },
 641         { "write-tree", cmd_write_tree, RUN_SETUP },
 642 };
 643
 644 static struct cmd_struct *get_builtin(const char *s)
 645 {
 646         int i;
 647         for (i = 0; i < ARRAY_SIZE(commands); i++) {
 648                 struct cmd_struct *p = commands + i;
 649                 if (!strcmp(s, p->cmd))
 650                         return p;
 651         }
 652         return NULL;
 653 }
 654
 655 int is_builtin(const char *s)
 656 {
 657         return !!get_builtin(s);
 658 }
 659
 660 static void list_builtins(struct string_list *out, unsigned int exclude_option)
 661 {
 662         int i;
 663         for (i = 0; i < ARRAY_SIZE(commands); i++) {
 664                 if (exclude_option &&
 665                     (commands[i].option & exclude_option))
 666                         continue;
 667                 string_list_append(out, commands[i].cmd);
 668         }
 669 }
 670
 671 void load_builtin_commands(const char *prefix, struct cmdnames *cmds)
 672 {
 673         const char *name;
 674         int i;
 675
 676         /*
 677          * Callers can ask for a subset of the commands based on a certain
 678          * prefix, which is then dropped from the added names. The names in
 679          * the `commands[]` array do not have the `git-` prefix, though,
 680          * therefore we must expect the `prefix` to at least start with `git-`.
 681          */
 682         if (!skip_prefix(prefix, "git-", &prefix))
 683                 BUG("prefix '%s' must start with 'git-'", prefix);
 684
 685         for (i = 0; i < ARRAY_SIZE(commands); i++)
 686                 if (skip_prefix(commands[i].cmd, prefix, &name))
 687                         add_cmdname(cmds, name, strlen(name));
 688 }
 689
 690 #ifdef STRIP_EXTENSION
 691 static void strip_extension(const char **argv)
 692 {
 693         size_t len;
 694
 695         if (strip_suffix(argv[0], STRIP_EXTENSION, &len))
 696                 argv[0] = xmemdupz(argv[0], len);
 697 }
 698 #else
 699 #define strip_extension(cmd)
 700 #endif
 701
 702 static void handle_builtin(int argc, const char **argv)
 703 {
 704         struct strvec args = STRVEC_INIT;
 705         const char *cmd;
 706         struct cmd_struct *builtin;
 707
 708         strip_extension(argv);
 709         cmd = argv[0];
 710
 711         /* Turn "git cmd --help" into "git help --exclude-guides cmd" */
 712         if (argc > 1 && !strcmp(argv[1], "--help")) {
 713                 int i;
 714
 715                 argv[1] = argv[0];
 716                 argv[0] = cmd = "help";
 717
 718                 for (i = 0; i < argc; i++) {
 719                         strvec_push(&args, argv[i]);
 720                         if (!i)
 721                                 strvec_push(&args, "--exclude-guides");
 722                 }
 723
 724                 argc++;
 725                 argv = args.v;
 726         }
 727
 728         builtin = get_builtin(cmd);
 729         if (builtin)
 730                 exit(run_builtin(builtin, argc, argv));
 731         strvec_clear(&args);
 732 }
 733
 734 static void execv_dashed_external(const char **argv)
 735 {
 736         struct child_process cmd = CHILD_PROCESS_INIT;
 737         int status;
 738
 739         if (use_pager == -1 && !is_builtin(argv[0]))
 740                 use_pager = check_pager_config(argv[0]);
 741         commit_pager_choice();
 742
 743         strvec_pushf(&cmd.args, "git-%s", argv[0]);
 744         strvec_pushv(&cmd.args, argv + 1);
 745         cmd.clean_on_exit = 1;
 746         cmd.wait_after_clean = 1;
 747         cmd.silent_exec_failure = 1;
 748         cmd.trace2_child_class = "dashed";
 749
 750         trace2_cmd_name("_run_dashed_");
 751
 752         /*
 753          * The code in run_command() logs trace2 child_start/child_exit
 754          * events, so we do not need to report exec/exec_result events here.
 755          */
 756         trace_argv_printf(cmd.args.v, "trace: exec:");
 757
 758         /*
 759          * If we fail because the command is not found, it is
 760          * OK to return. Otherwise, we just pass along the status code,
 761          * or our usual generic code if we were not even able to exec
 762          * the program.
 763          */
 764         status = run_command(&cmd);
 765
 766         /*
 767          * If the child process ran and we are now going to exit, emit a
 768          * generic string as our trace2 command verb to indicate that we
 769          * launched a dashed command.
 770          */
 771         if (status >= 0)
 772                 exit(status);
 773         else if (errno != ENOENT)
 774                 exit(128);
 775 }
 776
 777 static int run_argv(int *argcp, const char ***argv)
 778 {
 779         int done_alias = 0;
 780         struct string_list cmd_list = STRING_LIST_INIT_NODUP;
 781         struct string_list_item *seen;
 782
 783         while (1) {
 784                 /*
 785                  * If we tried alias and futzed with our environment,
 786                  * it no longer is safe to invoke builtins directly in
 787                  * general.  We have to spawn them as dashed externals.
 788                  *
 789                  * NEEDSWORK: if we can figure out cases
 790                  * where it is safe to do, we can avoid spawning a new
 791                  * process.
 792                  */
 793                 if (!done_alias)
 794                         handle_builtin(*argcp, *argv);
 795                 else if (get_builtin(**argv)) {
 796                         struct child_process cmd = CHILD_PROCESS_INIT;
 797                         int i;
 798
 799                         /*
 800                          * The current process is committed to launching a
 801                          * child process to run the command named in (**argv)
 802                          * and exiting.  Log a generic string as the trace2
 803                          * command verb to indicate this.  Note that the child
 804                          * process will log the actual verb when it runs.
 805                          */
 806                         trace2_cmd_name("_run_git_alias_");
 807
 808                         commit_pager_choice();
 809
 810                         strvec_push(&cmd.args, "git");
 811                         for (i = 0; i < *argcp; i++)
 812                                 strvec_push(&cmd.args, (*argv)[i]);
 813
 814                         trace_argv_printf(cmd.args.v, "trace: exec:");
 815
 816                         /*
 817                          * if we fail because the command is not found, it is
 818                          * OK to return. Otherwise, we just pass along the status code.
 819                          */
 820                         cmd.silent_exec_failure = 1;
 821                         cmd.clean_on_exit = 1;
 822                         cmd.wait_after_clean = 1;
 823                         cmd.trace2_child_class = "git_alias";
 824                         i = run_command(&cmd);
 825                         if (i >= 0 || errno != ENOENT)
 826                                 exit(i);
 827                         die("could not execute builtin %s", **argv);
 828                 }
 829
 830                 /* .. then try the external ones */
 831                 execv_dashed_external(*argv);
 832
 833                 seen = unsorted_string_list_lookup(&cmd_list, *argv[0]);
 834                 if (seen) {
 835                         int i;
 836                         struct strbuf sb = STRBUF_INIT;
 837                         for (i = 0; i < cmd_list.nr; i++) {
 838                                 struct string_list_item *item = &cmd_list.items[i];
 839
 840                                 strbuf_addf(&sb, "\n  %s", item->string);
 841                                 if (item == seen)
 842                                         strbuf_addstr(&sb, " <==");
 843                                 else if (i == cmd_list.nr - 1)
 844                                         strbuf_addstr(&sb, " ==>");
 845                         }
 846                         die(_("alias loop detected: expansion of '%s' does"
 847                               " not terminate:%s"), cmd_list.items[0].string, sb.buf);
 848                 }
 849
 850                 string_list_append(&cmd_list, *argv[0]);
 851
 852                 /*
 853                  * It could be an alias -- this works around the insanity
 854                  * of overriding "git log" with "git show" by having
 855                  * alias.log = show
 856                  */
 857                 if (!handle_alias(argcp, argv))
 858                         break;
 859                 done_alias = 1;
 860         }
 861
 862         string_list_clear(&cmd_list, 0);
 863
 864         return done_alias;
 865 }
 866
 867 int cmd_main(int argc, const char **argv)
 868 {
 869         const char *cmd;
 870         int done_help = 0;
 871
 872         cmd = argv[0];
 873         if (!cmd)
 874                 cmd = "git-help";
 875         else {
 876                 const char *slash = find_last_dir_sep(cmd);
 877                 if (slash)
 878                         cmd = slash + 1;
 879         }
 880
 881         trace_command_performance(argv);
 882
 883         /*
 884          * "git-xxxx" is the same as "git xxxx", but we obviously:
 885          *
 886          *  - cannot take flags in between the "git" and the "xxxx".
 887          *  - cannot execute it externally (since it would just do
 888          *    the same thing over again)
 889          *
 890          * So we just directly call the builtin handler, and die if
 891          * that one cannot handle it.
 892          */
 893         if (skip_prefix(cmd, "git-", &cmd)) {
 894                 argv[0] = cmd;
 895                 handle_builtin(argc, argv);
 896                 die(_("cannot handle %s as a builtin"), cmd);
 897         }
 898
 899         /* Look for flags.. */
 900         argv++;
 901         argc--;
 902         handle_options(&argv, &argc, NULL);
 903
 904         if (!argc) {
 905                 /* The user didn't specify a command; give them help */
 906                 commit_pager_choice();
 907                 printf(_("usage: %s\n\n"), git_usage_string);
 908                 list_common_cmds_help();
 909                 printf("\n%s\n", _(git_more_info_string));
 910                 exit(1);
 911         }
 912
 913         if (!strcmp("--version", argv[0]) || !strcmp("-v", argv[0]))
 914                 argv[0] = "version";
 915         else if (!strcmp("--help", argv[0]) || !strcmp("-h", argv[0]))
 916                 argv[0] = "help";
 917
 918         cmd = argv[0];
 919
 920         /*
 921          * We use PATH to find git commands, but we prepend some higher
 922          * precedence paths: the "--exec-path" option, the GIT_EXEC_PATH
 923          * environment, and the $(gitexecdir) from the Makefile at build
 924          * time.
 925          */
 926         setup_path();
 927
 928         while (1) {
 929                 int was_alias = run_argv(&argc, &argv);
 930                 if (errno != ENOENT)
 931                         break;
 932                 if (was_alias) {
 933                         fprintf(stderr, _("expansion of alias '%s' failed; "
 934                                           "'%s' is not a git command\n"),
 935                                 cmd, argv[0]);
 936                         exit(1);
 937                 }
 938                 if (!done_help) {
 939                         cmd = argv[0] = help_unknown_cmd(cmd);
 940                         done_help = 1;
 941                 } else
 942                         break;
 943         }
 944
 945         fprintf(stderr, _("failed to run command '%s': %s\n"),
 946                 cmd, strerror(errno));
 947
 948         return 1;
 949 }