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