git.oblomov.eu Git - git/blob - 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 struct startup_info git_startup_info;
  19 static int use_pager = -1;
  20 static char *orig_cwd;
  21 static const char *env_names[] = {
  22         GIT_DIR_ENVIRONMENT,
  23         GIT_WORK_TREE_ENVIRONMENT,
  24         GIT_IMPLICIT_WORK_TREE_ENVIRONMENT,
  25         GIT_PREFIX_ENVIRONMENT
  26 };
  27 static char *orig_env[4];
  28 static int saved_env_before_alias;
  29
  30 static void save_env_before_alias(void)
  31 {
  32         int i;
  33         saved_env_before_alias = 1;
  34         orig_cwd = xgetcwd();
  35         for (i = 0; i < ARRAY_SIZE(env_names); i++) {
  36                 orig_env[i] = getenv(env_names[i]);
  37                 if (orig_env[i])
  38                         orig_env[i] = xstrdup(orig_env[i]);
  39         }
  40 }
  41
  42 static void restore_env(int external_alias)
  43 {
  44         int i;
  45         if (!external_alias && orig_cwd && chdir(orig_cwd))
  46                 die_errno("could not move to %s", orig_cwd);
  47         free(orig_cwd);
  48         for (i = 0; i < ARRAY_SIZE(env_names); i++) {
  49                 if (external_alias &&
  50                     !strcmp(env_names[i], GIT_PREFIX_ENVIRONMENT))
  51                         continue;
  52                 if (orig_env[i])
  53                         setenv(env_names[i], orig_env[i], 1);
  54                 else
  55                         unsetenv(env_names[i]);
  56         }
  57 }
  58
  59 static void commit_pager_choice(void) {
  60         switch (use_pager) {
  61         case 0:
  62                 setenv("GIT_PAGER", "cat", 1);
  63                 break;
  64         case 1:
  65                 setup_pager();
  66                 break;
  67         default:
  68                 break;
  69         }
  70 }
  71
  72 static int handle_options(const char ***argv, int *argc, int *envchanged)
  73 {
  74         const char **orig_argv = *argv;
  75
  76         while (*argc > 0) {
  77                 const char *cmd = (*argv)[0];
  78                 if (cmd[0] != '-')
  79                         break;
  80
  81                 /*
  82                  * For legacy reasons, the "version" and "help"
  83                  * commands can be written with "--" prepended
  84                  * to make them look like flags.
  85                  */
  86                 if (!strcmp(cmd, "--help") || !strcmp(cmd, "--version"))
  87                         break;
  88
  89                 /*
  90                  * Check remaining flags.
  91                  */
  92                 if (skip_prefix(cmd, "--exec-path", &cmd)) {
  93                         if (*cmd == '=')
  94                                 git_set_argv_exec_path(cmd + 1);
  95                         else {
  96                                 puts(git_exec_path());
  97                                 exit(0);
  98                         }
  99                 } else if (!strcmp(cmd, "--html-path")) {
 100                         puts(system_path(GIT_HTML_PATH));
 101                         exit(0);
 102                 } else if (!strcmp(cmd, "--man-path")) {
 103                         puts(system_path(GIT_MAN_PATH));
 104                         exit(0);
 105                 } else if (!strcmp(cmd, "--info-path")) {
 106                         puts(system_path(GIT_INFO_PATH));
 107                         exit(0);
 108                 } else if (!strcmp(cmd, "-p") || !strcmp(cmd, "--paginate")) {
 109                         use_pager = 1;
 110                 } else if (!strcmp(cmd, "--no-pager")) {
 111                         use_pager = 0;
 112                         if (envchanged)
 113                                 *envchanged = 1;
 114                 } else if (!strcmp(cmd, "--no-replace-objects")) {
 115                         check_replace_refs = 0;
 116                         setenv(NO_REPLACE_OBJECTS_ENVIRONMENT, "1", 1);
 117                         if (envchanged)
 118                                 *envchanged = 1;
 119                 } else if (!strcmp(cmd, "--git-dir")) {
 120                         if (*argc < 2) {
 121                                 fprintf(stderr, "No directory given for --git-dir.\n" );
 122                                 usage(git_usage_string);
 123                         }
 124                         setenv(GIT_DIR_ENVIRONMENT, (*argv)[1], 1);
 125                         if (envchanged)
 126                                 *envchanged = 1;
 127                         (*argv)++;
 128                         (*argc)--;
 129                 } else if (skip_prefix(cmd, "--git-dir=", &cmd)) {
 130                         setenv(GIT_DIR_ENVIRONMENT, cmd, 1);
 131                         if (envchanged)
 132                                 *envchanged = 1;
 133                 } else if (!strcmp(cmd, "--namespace")) {
 134                         if (*argc < 2) {
 135                                 fprintf(stderr, "No namespace given for --namespace.\n" );
 136                                 usage(git_usage_string);
 137                         }
 138                         setenv(GIT_NAMESPACE_ENVIRONMENT, (*argv)[1], 1);
 139                         if (envchanged)
 140                                 *envchanged = 1;
 141                         (*argv)++;
 142                         (*argc)--;
 143                 } else if (skip_prefix(cmd, "--namespace=", &cmd)) {
 144                         setenv(GIT_NAMESPACE_ENVIRONMENT, cmd, 1);
 145                         if (envchanged)
 146                                 *envchanged = 1;
 147                 } else if (!strcmp(cmd, "--work-tree")) {
 148                         if (*argc < 2) {
 149                                 fprintf(stderr, "No directory given for --work-tree.\n" );
 150                                 usage(git_usage_string);
 151                         }
 152                         setenv(GIT_WORK_TREE_ENVIRONMENT, (*argv)[1], 1);
 153                         if (envchanged)
 154                                 *envchanged = 1;
 155                         (*argv)++;
 156                         (*argc)--;
 157                 } else if (skip_prefix(cmd, "--work-tree=", &cmd)) {
 158                         setenv(GIT_WORK_TREE_ENVIRONMENT, cmd, 1);
 159                         if (envchanged)
 160                                 *envchanged = 1;
 161                 } else if (!strcmp(cmd, "--bare")) {
 162                         char *cwd = xgetcwd();
 163                         is_bare_repository_cfg = 1;
 164                         setenv(GIT_DIR_ENVIRONMENT, cwd, 0);
 165                         free(cwd);
 166                         setenv(GIT_IMPLICIT_WORK_TREE_ENVIRONMENT, "0", 1);
 167                         if (envchanged)
 168                                 *envchanged = 1;
 169                 } else if (!strcmp(cmd, "-c")) {
 170                         if (*argc < 2) {
 171                                 fprintf(stderr, "-c expects a configuration string\n" );
 172                                 usage(git_usage_string);
 173                         }
 174                         git_config_push_parameter((*argv)[1]);
 175                         (*argv)++;
 176                         (*argc)--;
 177                 } else if (!strcmp(cmd, "--literal-pathspecs")) {
 178                         setenv(GIT_LITERAL_PATHSPECS_ENVIRONMENT, "1", 1);
 179                         if (envchanged)
 180                                 *envchanged = 1;
 181                 } else if (!strcmp(cmd, "--no-literal-pathspecs")) {
 182                         setenv(GIT_LITERAL_PATHSPECS_ENVIRONMENT, "0", 1);
 183                         if (envchanged)
 184                                 *envchanged = 1;
 185                 } else if (!strcmp(cmd, "--glob-pathspecs")) {
 186                         setenv(GIT_GLOB_PATHSPECS_ENVIRONMENT, "1", 1);
 187                         if (envchanged)
 188                                 *envchanged = 1;
 189                 } else if (!strcmp(cmd, "--noglob-pathspecs")) {
 190                         setenv(GIT_NOGLOB_PATHSPECS_ENVIRONMENT, "1", 1);
 191                         if (envchanged)
 192                                 *envchanged = 1;
 193                 } else if (!strcmp(cmd, "--icase-pathspecs")) {
 194                         setenv(GIT_ICASE_PATHSPECS_ENVIRONMENT, "1", 1);
 195                         if (envchanged)
 196                                 *envchanged = 1;
 197                 } else if (!strcmp(cmd, "--shallow-file")) {
 198                         (*argv)++;
 199                         (*argc)--;
 200                         set_alternate_shallow_file((*argv)[0], 1);
 201                         if (envchanged)
 202                                 *envchanged = 1;
 203                 } else if (!strcmp(cmd, "-C")) {
 204                         if (*argc < 2) {
 205                                 fprintf(stderr, "No directory given for -C.\n" );
 206                                 usage(git_usage_string);
 207                         }
 208                         if ((*argv)[1][0]) {
 209                                 if (chdir((*argv)[1]))
 210                                         die_errno("Cannot change to '%s'", (*argv)[1]);
 211                                 if (envchanged)
 212                                         *envchanged = 1;
 213                         }
 214                         (*argv)++;
 215                         (*argc)--;
 216                 } else {
 217                         fprintf(stderr, "Unknown option: %s\n", cmd);
 218                         usage(git_usage_string);
 219                 }
 220
 221                 (*argv)++;
 222                 (*argc)--;
 223         }
 224         return (*argv) - orig_argv;
 225 }
 226
 227 static int handle_alias(int *argcp, const char ***argv)
 228 {
 229         int envchanged = 0, ret = 0, saved_errno = errno;
 230         int count, option_count;
 231         const char **new_argv;
 232         const char *alias_command;
 233         char *alias_string;
 234         int unused_nongit;
 235
 236         save_env_before_alias();
 237         setup_git_directory_gently(&unused_nongit);
 238
 239         alias_command = (*argv)[0];
 240         alias_string = alias_lookup(alias_command);
 241         if (alias_string) {
 242                 if (alias_string[0] == '!') {
 243                         const char **alias_argv;
 244                         int argc = *argcp, i;
 245
 246                         commit_pager_choice();
 247                         restore_env(1);
 248
 249                         /* build alias_argv */
 250                         alias_argv = xmalloc(sizeof(*alias_argv) * (argc + 1));
 251                         alias_argv[0] = alias_string + 1;
 252                         for (i = 1; i < argc; ++i)
 253                                 alias_argv[i] = (*argv)[i];
 254                         alias_argv[argc] = NULL;
 255
 256                         ret = run_command_v_opt(alias_argv, RUN_USING_SHELL);
 257                         if (ret >= 0)   /* normal exit */
 258                                 exit(ret);
 259
 260                         die_errno("While expanding alias '%s': '%s'",
 261                             alias_command, alias_string + 1);
 262                 }
 263                 count = split_cmdline(alias_string, &new_argv);
 264                 if (count < 0)
 265                         die("Bad alias.%s string: %s", alias_command,
 266                             split_cmdline_strerror(count));
 267                 option_count = handle_options(&new_argv, &count, &envchanged);
 268                 if (envchanged)
 269                         die("alias '%s' changes environment variables\n"
 270                                  "You can use '!git' in the alias to do this.",
 271                                  alias_command);
 272                 memmove(new_argv - option_count, new_argv,
 273                                 count * sizeof(char *));
 274                 new_argv -= option_count;
 275
 276                 if (count < 1)
 277                         die("empty alias for %s", alias_command);
 278
 279                 if (!strcmp(alias_command, new_argv[0]))
 280                         die("recursive alias: %s", alias_command);
 281
 282                 trace_argv_printf(new_argv,
 283                                   "trace: alias expansion: %s =>",
 284                                   alias_command);
 285
 286                 REALLOC_ARRAY(new_argv, count + *argcp);
 287                 /* insert after command name */
 288                 memcpy(new_argv + count, *argv + 1, sizeof(char *) * *argcp);
 289
 290                 *argv = new_argv;
 291                 *argcp += count - 1;
 292
 293                 ret = 1;
 294         }
 295
 296         restore_env(0);
 297
 298         errno = saved_errno;
 299
 300         return ret;
 301 }
 302
 303 #define RUN_SETUP               (1<<0)
 304 #define RUN_SETUP_GENTLY        (1<<1)
 305 #define USE_PAGER               (1<<2)
 306 /*
 307  * require working tree to be present -- anything uses this needs
 308  * RUN_SETUP for reading from the configuration file.
 309  */
 310 #define NEED_WORK_TREE          (1<<3)
 311
 312 struct cmd_struct {
 313         const char *cmd;
 314         int (*fn)(int, const char **, const char *);
 315         int option;
 316 };
 317
 318 static int run_builtin(struct cmd_struct *p, int argc, const char **argv)
 319 {
 320         int status, help;
 321         struct stat st;
 322         const char *prefix;
 323
 324         prefix = NULL;
 325         help = argc == 2 && !strcmp(argv[1], "-h");
 326         if (!help) {
 327                 if (p->option & RUN_SETUP)
 328                         prefix = setup_git_directory();
 329                 else if (p->option & RUN_SETUP_GENTLY) {
 330                         int nongit_ok;
 331                         prefix = setup_git_directory_gently(&nongit_ok);
 332                 }
 333
 334                 if (use_pager == -1 && p->option & (RUN_SETUP | RUN_SETUP_GENTLY))
 335                         use_pager = check_pager_config(p->cmd);
 336                 if (use_pager == -1 && p->option & USE_PAGER)
 337                         use_pager = 1;
 338
 339                 if ((p->option & (RUN_SETUP | RUN_SETUP_GENTLY)) &&
 340                     startup_info->have_repository) /* get_git_dir() may set up repo, avoid that */
 341                         trace_repo_setup(prefix);
 342         }
 343         commit_pager_choice();
 344
 345         if (!help && p->option & NEED_WORK_TREE)
 346                 setup_work_tree();
 347
 348         trace_argv_printf(argv, "trace: built-in: git");
 349
 350         status = p->fn(argc, argv, prefix);
 351         if (status)
 352                 return status;
 353
 354         /* Somebody closed stdout? */
 355         if (fstat(fileno(stdout), &st))
 356                 return 0;
 357         /* Ignore write errors for pipes and sockets.. */
 358         if (S_ISFIFO(st.st_mode) || S_ISSOCK(st.st_mode))
 359                 return 0;
 360
 361         /* Check for ENOSPC and EIO errors.. */
 362         if (fflush(stdout))
 363                 die_errno("write failure on standard output");
 364         if (ferror(stdout))
 365                 die("unknown write failure on standard output");
 366         if (fclose(stdout))
 367                 die_errno("close failed on standard output");
 368         return 0;
 369 }
 370
 371 static struct cmd_struct commands[] = {
 372         { "add", cmd_add, RUN_SETUP | NEED_WORK_TREE },
 373         { "annotate", cmd_annotate, RUN_SETUP },
 374         { "apply", cmd_apply, RUN_SETUP_GENTLY },
 375         { "archive", cmd_archive },
 376         { "bisect--helper", cmd_bisect__helper, RUN_SETUP },
 377         { "blame", cmd_blame, RUN_SETUP },
 378         { "branch", cmd_branch, RUN_SETUP },
 379         { "bundle", cmd_bundle, RUN_SETUP_GENTLY },
 380         { "cat-file", cmd_cat_file, RUN_SETUP },
 381         { "check-attr", cmd_check_attr, RUN_SETUP },
 382         { "check-ignore", cmd_check_ignore, RUN_SETUP | NEED_WORK_TREE },
 383         { "check-mailmap", cmd_check_mailmap, RUN_SETUP },
 384         { "check-ref-format", cmd_check_ref_format },
 385         { "checkout", cmd_checkout, RUN_SETUP | NEED_WORK_TREE },
 386         { "checkout-index", cmd_checkout_index,
 387                 RUN_SETUP | NEED_WORK_TREE},
 388         { "cherry", cmd_cherry, RUN_SETUP },
 389         { "cherry-pick", cmd_cherry_pick, RUN_SETUP | NEED_WORK_TREE },
 390         { "clean", cmd_clean, RUN_SETUP | NEED_WORK_TREE },
 391         { "clone", cmd_clone },
 392         { "column", cmd_column, RUN_SETUP_GENTLY },
 393         { "commit", cmd_commit, RUN_SETUP | NEED_WORK_TREE },
 394         { "commit-tree", cmd_commit_tree, RUN_SETUP },
 395         { "config", cmd_config, RUN_SETUP_GENTLY },
 396         { "count-objects", cmd_count_objects, RUN_SETUP },
 397         { "credential", cmd_credential, RUN_SETUP_GENTLY },
 398         { "describe", cmd_describe, RUN_SETUP },
 399         { "diff", cmd_diff },
 400         { "diff-files", cmd_diff_files, RUN_SETUP | NEED_WORK_TREE },
 401         { "diff-index", cmd_diff_index, RUN_SETUP },
 402         { "diff-tree", cmd_diff_tree, RUN_SETUP },
 403         { "fast-export", cmd_fast_export, RUN_SETUP },
 404         { "fetch", cmd_fetch, RUN_SETUP },
 405         { "fetch-pack", cmd_fetch_pack, RUN_SETUP },
 406         { "fmt-merge-msg", cmd_fmt_merge_msg, RUN_SETUP },
 407         { "for-each-ref", cmd_for_each_ref, RUN_SETUP },
 408         { "format-patch", cmd_format_patch, RUN_SETUP },
 409         { "fsck", cmd_fsck, RUN_SETUP },
 410         { "fsck-objects", cmd_fsck, RUN_SETUP },
 411         { "gc", cmd_gc, RUN_SETUP },
 412         { "get-tar-commit-id", cmd_get_tar_commit_id },
 413         { "grep", cmd_grep, RUN_SETUP_GENTLY },
 414         { "hash-object", cmd_hash_object },
 415         { "help", cmd_help },
 416         { "index-pack", cmd_index_pack, RUN_SETUP_GENTLY },
 417         { "init", cmd_init_db },
 418         { "init-db", cmd_init_db },
 419         { "interpret-trailers", cmd_interpret_trailers, RUN_SETUP },
 420         { "log", cmd_log, RUN_SETUP },
 421         { "ls-files", cmd_ls_files, RUN_SETUP },
 422         { "ls-remote", cmd_ls_remote, RUN_SETUP_GENTLY },
 423         { "ls-tree", cmd_ls_tree, RUN_SETUP },
 424         { "mailinfo", cmd_mailinfo },
 425         { "mailsplit", cmd_mailsplit },
 426         { "merge", cmd_merge, RUN_SETUP | NEED_WORK_TREE },
 427         { "merge-base", cmd_merge_base, RUN_SETUP },
 428         { "merge-file", cmd_merge_file, RUN_SETUP_GENTLY },
 429         { "merge-index", cmd_merge_index, RUN_SETUP },
 430         { "merge-ours", cmd_merge_ours, RUN_SETUP },
 431         { "merge-recursive", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE },
 432         { "merge-recursive-ours", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE },
 433         { "merge-recursive-theirs", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE },
 434         { "merge-subtree", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE },
 435         { "merge-tree", cmd_merge_tree, RUN_SETUP },
 436         { "mktag", cmd_mktag, RUN_SETUP },
 437         { "mktree", cmd_mktree, RUN_SETUP },
 438         { "mv", cmd_mv, RUN_SETUP | NEED_WORK_TREE },
 439         { "name-rev", cmd_name_rev, RUN_SETUP },
 440         { "notes", cmd_notes, RUN_SETUP },
 441         { "pack-objects", cmd_pack_objects, RUN_SETUP },
 442         { "pack-redundant", cmd_pack_redundant, RUN_SETUP },
 443         { "pack-refs", cmd_pack_refs, RUN_SETUP },
 444         { "patch-id", cmd_patch_id },
 445         { "pickaxe", cmd_blame, RUN_SETUP },
 446         { "prune", cmd_prune, RUN_SETUP },
 447         { "prune-packed", cmd_prune_packed, RUN_SETUP },
 448         { "push", cmd_push, RUN_SETUP },
 449         { "read-tree", cmd_read_tree, RUN_SETUP },
 450         { "receive-pack", cmd_receive_pack },
 451         { "reflog", cmd_reflog, RUN_SETUP },
 452         { "remote", cmd_remote, RUN_SETUP },
 453         { "remote-ext", cmd_remote_ext },
 454         { "remote-fd", cmd_remote_fd },
 455         { "repack", cmd_repack, RUN_SETUP },
 456         { "replace", cmd_replace, RUN_SETUP },
 457         { "rerere", cmd_rerere, RUN_SETUP },
 458         { "reset", cmd_reset, RUN_SETUP },
 459         { "rev-list", cmd_rev_list, RUN_SETUP },
 460         { "rev-parse", cmd_rev_parse },
 461         { "revert", cmd_revert, RUN_SETUP | NEED_WORK_TREE },
 462         { "rm", cmd_rm, RUN_SETUP },
 463         { "send-pack", cmd_send_pack, RUN_SETUP },
 464         { "shortlog", cmd_shortlog, RUN_SETUP_GENTLY | USE_PAGER },
 465         { "show", cmd_show, RUN_SETUP },
 466         { "show-branch", cmd_show_branch, RUN_SETUP },
 467         { "show-ref", cmd_show_ref, RUN_SETUP },
 468         { "stage", cmd_add, RUN_SETUP | NEED_WORK_TREE },
 469         { "status", cmd_status, RUN_SETUP | NEED_WORK_TREE },
 470         { "stripspace", cmd_stripspace },
 471         { "symbolic-ref", cmd_symbolic_ref, RUN_SETUP },
 472         { "tag", cmd_tag, RUN_SETUP },
 473         { "unpack-file", cmd_unpack_file, RUN_SETUP },
 474         { "unpack-objects", cmd_unpack_objects, RUN_SETUP },
 475         { "update-index", cmd_update_index, RUN_SETUP },
 476         { "update-ref", cmd_update_ref, RUN_SETUP },
 477         { "update-server-info", cmd_update_server_info, RUN_SETUP },
 478         { "upload-archive", cmd_upload_archive },
 479         { "upload-archive--writer", cmd_upload_archive_writer },
 480         { "var", cmd_var, RUN_SETUP_GENTLY },
 481         { "verify-commit", cmd_verify_commit, RUN_SETUP },
 482         { "verify-pack", cmd_verify_pack },
 483         { "verify-tag", cmd_verify_tag, RUN_SETUP },
 484         { "version", cmd_version },
 485         { "whatchanged", cmd_whatchanged, RUN_SETUP },
 486         { "worktree", cmd_worktree, RUN_SETUP },
 487         { "write-tree", cmd_write_tree, RUN_SETUP },
 488 };
 489
 490 static struct cmd_struct *get_builtin(const char *s)
 491 {
 492         int i;
 493         for (i = 0; i < ARRAY_SIZE(commands); i++) {
 494                 struct cmd_struct *p = commands + i;
 495                 if (!strcmp(s, p->cmd))
 496                         return p;
 497         }
 498         return NULL;
 499 }
 500
 501 int is_builtin(const char *s)
 502 {
 503         return !!get_builtin(s);
 504 }
 505
 506 static void handle_builtin(int argc, const char **argv)
 507 {
 508         const char *cmd = argv[0];
 509         int i;
 510         static const char ext[] = STRIP_EXTENSION;
 511         struct cmd_struct *builtin;
 512
 513         if (sizeof(ext) > 1) {
 514                 i = strlen(argv[0]) - strlen(ext);
 515                 if (i > 0 && !strcmp(argv[0] + i, ext)) {
 516                         char *argv0 = xstrdup(argv[0]);
 517                         argv[0] = cmd = argv0;
 518                         argv0[i] = '\0';
 519                 }
 520         }
 521
 522         /* Turn "git cmd --help" into "git help cmd" */
 523         if (argc > 1 && !strcmp(argv[1], "--help")) {
 524                 argv[1] = argv[0];
 525                 argv[0] = cmd = "help";
 526         }
 527
 528         builtin = get_builtin(cmd);
 529         if (builtin) {
 530                 /*
 531                  * XXX: if we can figure out cases where it is _safe_
 532                  * to do, we can avoid spawning a new process when
 533                  * saved_env_before_alias is true
 534                  * (i.e. setup_git_dir* has been run once)
 535                  */
 536                 if (!saved_env_before_alias)
 537                         exit(run_builtin(builtin, argc, argv));
 538         }
 539 }
 540
 541 static void execv_dashed_external(const char **argv)
 542 {
 543         struct strbuf cmd = STRBUF_INIT;
 544         const char *tmp;
 545         int status;
 546
 547         if (use_pager == -1)
 548                 use_pager = check_pager_config(argv[0]);
 549         commit_pager_choice();
 550
 551         strbuf_addf(&cmd, "git-%s", argv[0]);
 552
 553         /*
 554          * argv[0] must be the git command, but the argv array
 555          * belongs to the caller, and may be reused in
 556          * subsequent loop iterations. Save argv[0] and
 557          * restore it on error.
 558          */
 559         tmp = argv[0];
 560         argv[0] = cmd.buf;
 561
 562         trace_argv_printf(argv, "trace: exec:");
 563
 564         /*
 565          * if we fail because the command is not found, it is
 566          * OK to return. Otherwise, we just pass along the status code.
 567          */
 568         status = run_command_v_opt(argv, RUN_SILENT_EXEC_FAILURE | RUN_CLEAN_ON_EXIT);
 569         if (status >= 0 || errno != ENOENT)
 570                 exit(status);
 571
 572         argv[0] = tmp;
 573
 574         strbuf_release(&cmd);
 575 }
 576
 577 static int run_argv(int *argcp, const char ***argv)
 578 {
 579         int done_alias = 0;
 580
 581         while (1) {
 582                 /* See if it's a builtin */
 583                 handle_builtin(*argcp, *argv);
 584
 585                 /* .. then try the external ones */
 586                 execv_dashed_external(*argv);
 587
 588                 /* It could be an alias -- this works around the insanity
 589                  * of overriding "git log" with "git show" by having
 590                  * alias.log = show
 591                  */
 592                 if (done_alias)
 593                         break;
 594                 if (!handle_alias(argcp, argv))
 595                         break;
 596                 done_alias = 1;
 597         }
 598
 599         return done_alias;
 600 }
 601
 602 /*
 603  * Many parts of Git have subprograms communicate via pipe, expect the
 604  * upstream of a pipe to die with SIGPIPE when the downstream of a
 605  * pipe does not need to read all that is written.  Some third-party
 606  * programs that ignore or block SIGPIPE for their own reason forget
 607  * to restore SIGPIPE handling to the default before spawning Git and
 608  * break this carefully orchestrated machinery.
 609  *
 610  * Restore the way SIGPIPE is handled to default, which is what we
 611  * expect.
 612  */
 613 static void restore_sigpipe_to_default(void)
 614 {
 615         sigset_t unblock;
 616
 617         sigemptyset(&unblock);
 618         sigaddset(&unblock, SIGPIPE);
 619         sigprocmask(SIG_UNBLOCK, &unblock, NULL);
 620         signal(SIGPIPE, SIG_DFL);
 621 }
 622
 623 int main(int argc, char **av)
 624 {
 625         const char **argv = (const char **) av;
 626         const char *cmd;
 627         int done_help = 0;
 628
 629         startup_info = &git_startup_info;
 630
 631         cmd = git_extract_argv0_path(argv[0]);
 632         if (!cmd)
 633                 cmd = "git-help";
 634
 635         /*
 636          * Always open file descriptors 0/1/2 to avoid clobbering files
 637          * in die().  It also avoids messing up when the pipes are dup'ed
 638          * onto stdin/stdout/stderr in the child processes we spawn.
 639          */
 640         sanitize_stdfds();
 641
 642         restore_sigpipe_to_default();
 643
 644         git_setup_gettext();
 645
 646         trace_command_performance(argv);
 647
 648         /*
 649          * "git-xxxx" is the same as "git xxxx", but we obviously:
 650          *
 651          *  - cannot take flags in between the "git" and the "xxxx".
 652          *  - cannot execute it externally (since it would just do
 653          *    the same thing over again)
 654          *
 655          * So we just directly call the builtin handler, and die if
 656          * that one cannot handle it.
 657          */
 658         if (skip_prefix(cmd, "git-", &cmd)) {
 659                 argv[0] = cmd;
 660                 handle_builtin(argc, argv);
 661                 die("cannot handle %s as a builtin", cmd);
 662         }
 663
 664         /* Look for flags.. */
 665         argv++;
 666         argc--;
 667         handle_options(&argv, &argc, NULL);
 668         if (argc > 0) {
 669                 /* translate --help and --version into commands */
 670                 skip_prefix(argv[0], "--", &argv[0]);
 671         } else {
 672                 /* The user didn't specify a command; give them help */
 673                 commit_pager_choice();
 674                 printf("usage: %s\n\n", git_usage_string);
 675                 list_common_cmds_help();
 676                 printf("\n%s\n", _(git_more_info_string));
 677                 exit(1);
 678         }
 679         cmd = argv[0];
 680
 681         /*
 682          * We use PATH to find git commands, but we prepend some higher
 683          * precedence paths: the "--exec-path" option, the GIT_EXEC_PATH
 684          * environment, and the $(gitexecdir) from the Makefile at build
 685          * time.
 686          */
 687         setup_path();
 688
 689         while (1) {
 690                 int was_alias = run_argv(&argc, &argv);
 691                 if (errno != ENOENT)
 692                         break;
 693                 if (was_alias) {
 694                         fprintf(stderr, "Expansion of alias '%s' failed; "
 695                                 "'%s' is not a git command\n",
 696                                 cmd, argv[0]);
 697                         exit(1);
 698                 }
 699                 if (!done_help) {
 700                         cmd = argv[0] = help_unknown_cmd(cmd);
 701                         done_help = 1;
 702                 } else
 703                         break;
 704         }
 705
 706         fprintf(stderr, "Failed to run command '%s': %s\n",
 707                 cmd, strerror(errno));
 708
 709         return 1;
 710 }