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