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