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_environment;
  29
  30 static void save_env(void)
  31 {
  32         int i;
  33         if (saved_environment)
  34                 return;
  35         saved_environment = 1;
  36         orig_cwd = xgetcwd();
  37         for (i = 0; i < ARRAY_SIZE(env_names); i++) {
  38                 orig_env[i] = getenv(env_names[i]);
  39                 if (orig_env[i])
  40                         orig_env[i] = xstrdup(orig_env[i]);
  41         }
  42 }
  43
  44 static void restore_env(void)
  45 {
  46         int i;
  47         if (orig_cwd && chdir(orig_cwd))
  48                 die_errno("could not move to %s", orig_cwd);
  49         free(orig_cwd);
  50         for (i = 0; i < ARRAY_SIZE(env_names); i++) {
  51                 if (orig_env[i])
  52                         setenv(env_names[i], orig_env[i], 1);
  53                 else
  54                         unsetenv(env_names[i]);
  55         }
  56 }
  57
  58 static void commit_pager_choice(void) {
  59         switch (use_pager) {
  60         case 0:
  61                 setenv("GIT_PAGER", "cat", 1);
  62                 break;
  63         case 1:
  64                 setup_pager();
  65                 break;
  66         default:
  67                 break;
  68         }
  69 }
  70
  71 static int handle_options(const char ***argv, int *argc, int *envchanged)
  72 {
  73         const char **orig_argv = *argv;
  74
  75         while (*argc > 0) {
  76                 const char *cmd = (*argv)[0];
  77                 if (cmd[0] != '-')
  78                         break;
  79
  80                 /*
  81                  * For legacy reasons, the "version" and "help"
  82                  * commands can be written with "--" prepended
  83                  * to make them look like flags.
  84                  */
  85                 if (!strcmp(cmd, "--help") || !strcmp(cmd, "--version"))
  86                         break;
  87
  88                 /*
  89                  * Check remaining flags.
  90                  */
  91                 if (skip_prefix(cmd, "--exec-path", &cmd)) {
  92                         if (*cmd == '=')
  93                                 git_set_argv_exec_path(cmd + 1);
  94                         else {
  95                                 puts(git_exec_path());
  96                                 exit(0);
  97                         }
  98                 } else if (!strcmp(cmd, "--html-path")) {
  99                         puts(system_path(GIT_HTML_PATH));
 100                         exit(0);
 101                 } else if (!strcmp(cmd, "--man-path")) {
 102                         puts(system_path(GIT_MAN_PATH));
 103                         exit(0);
 104                 } else if (!strcmp(cmd, "--info-path")) {
 105                         puts(system_path(GIT_INFO_PATH));
 106                         exit(0);
 107                 } else if (!strcmp(cmd, "-p") || !strcmp(cmd, "--paginate")) {
 108                         use_pager = 1;
 109                 } else if (!strcmp(cmd, "--no-pager")) {
 110                         use_pager = 0;
 111                         if (envchanged)
 112                                 *envchanged = 1;
 113                 } else if (!strcmp(cmd, "--no-replace-objects")) {
 114                         check_replace_refs = 0;
 115                         setenv(NO_REPLACE_OBJECTS_ENVIRONMENT, "1", 1);
 116                         if (envchanged)
 117                                 *envchanged = 1;
 118                 } else if (!strcmp(cmd, "--git-dir")) {
 119                         if (*argc < 2) {
 120                                 fprintf(stderr, "No directory given for --git-dir.\n" );
 121                                 usage(git_usage_string);
 122                         }
 123                         setenv(GIT_DIR_ENVIRONMENT, (*argv)[1], 1);
 124                         if (envchanged)
 125                                 *envchanged = 1;
 126                         (*argv)++;
 127                         (*argc)--;
 128                 } else if (skip_prefix(cmd, "--git-dir=", &cmd)) {
 129                         setenv(GIT_DIR_ENVIRONMENT, cmd, 1);
 130                         if (envchanged)
 131                                 *envchanged = 1;
 132                 } else if (!strcmp(cmd, "--namespace")) {
 133                         if (*argc < 2) {
 134                                 fprintf(stderr, "No namespace given for --namespace.\n" );
 135                                 usage(git_usage_string);
 136                         }
 137                         setenv(GIT_NAMESPACE_ENVIRONMENT, (*argv)[1], 1);
 138                         if (envchanged)
 139                                 *envchanged = 1;
 140                         (*argv)++;
 141                         (*argc)--;
 142                 } else if (skip_prefix(cmd, "--namespace=", &cmd)) {
 143                         setenv(GIT_NAMESPACE_ENVIRONMENT, cmd, 1);
 144                         if (envchanged)
 145                                 *envchanged = 1;
 146                 } else if (!strcmp(cmd, "--work-tree")) {
 147                         if (*argc < 2) {
 148                                 fprintf(stderr, "No directory given for --work-tree.\n" );
 149                                 usage(git_usage_string);
 150                         }
 151                         setenv(GIT_WORK_TREE_ENVIRONMENT, (*argv)[1], 1);
 152                         if (envchanged)
 153                                 *envchanged = 1;
 154                         (*argv)++;
 155                         (*argc)--;
 156                 } else if (skip_prefix(cmd, "--work-tree=", &cmd)) {
 157                         setenv(GIT_WORK_TREE_ENVIRONMENT, cmd, 1);
 158                         if (envchanged)
 159                                 *envchanged = 1;
 160                 } else if (!strcmp(cmd, "--bare")) {
 161                         char *cwd = xgetcwd();
 162                         is_bare_repository_cfg = 1;
 163                         setenv(GIT_DIR_ENVIRONMENT, cwd, 0);
 164                         free(cwd);
 165                         setenv(GIT_IMPLICIT_WORK_TREE_ENVIRONMENT, "0", 1);
 166                         if (envchanged)
 167                                 *envchanged = 1;
 168                 } else if (!strcmp(cmd, "-c")) {
 169                         if (*argc < 2) {
 170                                 fprintf(stderr, "-c expects a configuration string\n" );
 171                                 usage(git_usage_string);
 172                         }
 173                         git_config_push_parameter((*argv)[1]);
 174                         (*argv)++;
 175                         (*argc)--;
 176                 } else if (!strcmp(cmd, "--literal-pathspecs")) {
 177                         setenv(GIT_LITERAL_PATHSPECS_ENVIRONMENT, "1", 1);
 178                         if (envchanged)
 179                                 *envchanged = 1;
 180                 } else if (!strcmp(cmd, "--no-literal-pathspecs")) {
 181                         setenv(GIT_LITERAL_PATHSPECS_ENVIRONMENT, "0", 1);
 182                         if (envchanged)
 183                                 *envchanged = 1;
 184                 } else if (!strcmp(cmd, "--glob-pathspecs")) {
 185                         setenv(GIT_GLOB_PATHSPECS_ENVIRONMENT, "1", 1);
 186                         if (envchanged)
 187                                 *envchanged = 1;
 188                 } else if (!strcmp(cmd, "--noglob-pathspecs")) {
 189                         setenv(GIT_NOGLOB_PATHSPECS_ENVIRONMENT, "1", 1);
 190                         if (envchanged)
 191                                 *envchanged = 1;
 192                 } else if (!strcmp(cmd, "--icase-pathspecs")) {
 193                         setenv(GIT_ICASE_PATHSPECS_ENVIRONMENT, "1", 1);
 194                         if (envchanged)
 195                                 *envchanged = 1;
 196                 } else if (!strcmp(cmd, "--shallow-file")) {
 197                         (*argv)++;
 198                         (*argc)--;
 199                         set_alternate_shallow_file((*argv)[0], 1);
 200                         if (envchanged)
 201                                 *envchanged = 1;
 202                 } else if (!strcmp(cmd, "-C")) {
 203                         if (*argc < 2) {
 204                                 fprintf(stderr, "No directory given for -C.\n" );
 205                                 usage(git_usage_string);
 206                         }
 207                         if ((*argv)[1][0]) {
 208                                 if (chdir((*argv)[1]))
 209                                         die_errno("Cannot change to '%s'", (*argv)[1]);
 210                                 if (envchanged)
 211                                         *envchanged = 1;
 212                         }
 213                         (*argv)++;
 214                         (*argc)--;
 215                 } else {
 216                         fprintf(stderr, "Unknown option: %s\n", cmd);
 217                         usage(git_usage_string);
 218                 }
 219
 220                 (*argv)++;
 221                 (*argc)--;
 222         }
 223         return (*argv) - orig_argv;
 224 }
 225
 226 static int handle_alias(int *argcp, const char ***argv)
 227 {
 228         int envchanged = 0, ret = 0, saved_errno = errno;
 229         const char *subdir;
 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         subdir = setup_git_directory_gently(&unused_nongit);
 237
 238         alias_command = (*argv)[0];
 239         alias_string = alias_lookup(alias_command);
 240         if (alias_string) {
 241                 if (alias_string[0] == '!') {
 242                         const char **alias_argv;
 243                         int argc = *argcp, i;
 244
 245                         commit_pager_choice();
 246
 247                         /* build alias_argv */
 248                         alias_argv = xmalloc(sizeof(*alias_argv) * (argc + 1));
 249                         alias_argv[0] = alias_string + 1;
 250                         for (i = 1; i < argc; ++i)
 251                                 alias_argv[i] = (*argv)[i];
 252                         alias_argv[argc] = NULL;
 253
 254                         ret = run_command_v_opt(alias_argv, RUN_USING_SHELL);
 255                         if (ret >= 0)   /* normal exit */
 256                                 exit(ret);
 257
 258                         die_errno("While expanding alias '%s': '%s'",
 259                             alias_command, alias_string + 1);
 260                 }
 261                 count = split_cmdline(alias_string, &new_argv);
 262                 if (count < 0)
 263                         die("Bad alias.%s string: %s", alias_command,
 264                             split_cmdline_strerror(count));
 265                 option_count = handle_options(&new_argv, &count, &envchanged);
 266                 if (envchanged)
 267                         die("alias '%s' changes environment variables\n"
 268                                  "You can use '!git' in the alias to do this.",
 269                                  alias_command);
 270                 memmove(new_argv - option_count, new_argv,
 271                                 count * sizeof(char *));
 272                 new_argv -= option_count;
 273
 274                 if (count < 1)
 275                         die("empty alias for %s", alias_command);
 276
 277                 if (!strcmp(alias_command, new_argv[0]))
 278                         die("recursive alias: %s", alias_command);
 279
 280                 trace_argv_printf(new_argv,
 281                                   "trace: alias expansion: %s =>",
 282                                   alias_command);
 283
 284                 REALLOC_ARRAY(new_argv, count + *argcp);
 285                 /* insert after command name */
 286                 memcpy(new_argv + count, *argv + 1, sizeof(char *) * *argcp);
 287
 288                 *argv = new_argv;
 289                 *argcp += count - 1;
 290
 291                 ret = 1;
 292         }
 293
 294         if (subdir && chdir(subdir))
 295                 die_errno("Cannot change to '%s'", subdir);
 296
 297         errno = saved_errno;
 298
 299         return ret;
 300 }
 301
 302 #define RUN_SETUP               (1<<0)
 303 #define RUN_SETUP_GENTLY        (1<<1)
 304 #define USE_PAGER               (1<<2)
 305 /*
 306  * require working tree to be present -- anything uses this needs
 307  * RUN_SETUP for reading from the configuration file.
 308  */
 309 #define NEED_WORK_TREE          (1<<3)
 310 #define NO_SETUP                (1<<4)
 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 },
 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, NO_SETUP },
 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, NO_SETUP },
 418         { "init-db", cmd_init_db, NO_SETUP },
 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         { "write-tree", cmd_write_tree, RUN_SETUP },
 487 };
 488
 489 static struct cmd_struct *get_builtin(const char *s)
 490 {
 491         int i;
 492         for (i = 0; i < ARRAY_SIZE(commands); i++) {
 493                 struct cmd_struct *p = commands + i;
 494                 if (!strcmp(s, p->cmd))
 495                         return p;
 496         }
 497         return NULL;
 498 }
 499
 500 int is_builtin(const char *s)
 501 {
 502         return !!get_builtin(s);
 503 }
 504
 505 static void handle_builtin(int argc, const char **argv)
 506 {
 507         const char *cmd = argv[0];
 508         int i;
 509         static const char ext[] = STRIP_EXTENSION;
 510         struct cmd_struct *builtin;
 511
 512         if (sizeof(ext) > 1) {
 513                 i = strlen(argv[0]) - strlen(ext);
 514                 if (i > 0 && !strcmp(argv[0] + i, ext)) {
 515                         char *argv0 = xstrdup(argv[0]);
 516                         argv[0] = cmd = argv0;
 517                         argv0[i] = '\0';
 518                 }
 519         }
 520
 521         /* Turn "git cmd --help" into "git help cmd" */
 522         if (argc > 1 && !strcmp(argv[1], "--help")) {
 523                 argv[1] = argv[0];
 524                 argv[0] = cmd = "help";
 525         }
 526
 527         builtin = get_builtin(cmd);
 528         if (builtin) {
 529                 if (saved_environment && (builtin->option & NO_SETUP))
 530                         restore_env();
 531                 else
 532                         exit(run_builtin(builtin, argc, argv));
 533         }
 534 }
 535
 536 static void execv_dashed_external(const char **argv)
 537 {
 538         struct strbuf cmd = STRBUF_INIT;
 539         const char *tmp;
 540         int status;
 541
 542         if (use_pager == -1)
 543                 use_pager = check_pager_config(argv[0]);
 544         commit_pager_choice();
 545
 546         strbuf_addf(&cmd, "git-%s", argv[0]);
 547
 548         /*
 549          * argv[0] must be the git command, but the argv array
 550          * belongs to the caller, and may be reused in
 551          * subsequent loop iterations. Save argv[0] and
 552          * restore it on error.
 553          */
 554         tmp = argv[0];
 555         argv[0] = cmd.buf;
 556
 557         trace_argv_printf(argv, "trace: exec:");
 558
 559         /*
 560          * if we fail because the command is not found, it is
 561          * OK to return. Otherwise, we just pass along the status code.
 562          */
 563         status = run_command_v_opt(argv, RUN_SILENT_EXEC_FAILURE | RUN_CLEAN_ON_EXIT);
 564         if (status >= 0 || errno != ENOENT)
 565                 exit(status);
 566
 567         argv[0] = tmp;
 568
 569         strbuf_release(&cmd);
 570 }
 571
 572 static int run_argv(int *argcp, const char ***argv)
 573 {
 574         int done_alias = 0;
 575
 576         while (1) {
 577                 /* See if it's a builtin */
 578                 handle_builtin(*argcp, *argv);
 579
 580                 /* .. then try the external ones */
 581                 execv_dashed_external(*argv);
 582
 583                 /* It could be an alias -- this works around the insanity
 584                  * of overriding "git log" with "git show" by having
 585                  * alias.log = show
 586                  */
 587                 if (done_alias)
 588                         break;
 589                 save_env();
 590                 if (!handle_alias(argcp, argv))
 591                         break;
 592                 done_alias = 1;
 593         }
 594
 595         return done_alias;
 596 }
 597
 598 /*
 599  * Many parts of Git have subprograms communicate via pipe, expect the
 600  * upstream of a pipe to die with SIGPIPE when the downstream of a
 601  * pipe does not need to read all that is written.  Some third-party
 602  * programs that ignore or block SIGPIPE for their own reason forget
 603  * to restore SIGPIPE handling to the default before spawning Git and
 604  * break this carefully orchestrated machinery.
 605  *
 606  * Restore the way SIGPIPE is handled to default, which is what we
 607  * expect.
 608  */
 609 static void restore_sigpipe_to_default(void)
 610 {
 611         sigset_t unblock;
 612
 613         sigemptyset(&unblock);
 614         sigaddset(&unblock, SIGPIPE);
 615         sigprocmask(SIG_UNBLOCK, &unblock, NULL);
 616         signal(SIGPIPE, SIG_DFL);
 617 }
 618
 619 int main(int argc, char **av)
 620 {
 621         const char **argv = (const char **) av;
 622         const char *cmd;
 623         int done_help = 0;
 624
 625         startup_info = &git_startup_info;
 626
 627         cmd = git_extract_argv0_path(argv[0]);
 628         if (!cmd)
 629                 cmd = "git-help";
 630
 631         /*
 632          * Always open file descriptors 0/1/2 to avoid clobbering files
 633          * in die().  It also avoids messing up when the pipes are dup'ed
 634          * onto stdin/stdout/stderr in the child processes we spawn.
 635          */
 636         sanitize_stdfds();
 637
 638         restore_sigpipe_to_default();
 639
 640         git_setup_gettext();
 641
 642         trace_command_performance(argv);
 643
 644         /*
 645          * "git-xxxx" is the same as "git xxxx", but we obviously:
 646          *
 647          *  - cannot take flags in between the "git" and the "xxxx".
 648          *  - cannot execute it externally (since it would just do
 649          *    the same thing over again)
 650          *
 651          * So we just directly call the builtin handler, and die if
 652          * that one cannot handle it.
 653          */
 654         if (skip_prefix(cmd, "git-", &cmd)) {
 655                 argv[0] = cmd;
 656                 handle_builtin(argc, argv);
 657                 die("cannot handle %s as a builtin", cmd);
 658         }
 659
 660         /* Look for flags.. */
 661         argv++;
 662         argc--;
 663         handle_options(&argv, &argc, NULL);
 664         if (argc > 0) {
 665                 /* translate --help and --version into commands */
 666                 skip_prefix(argv[0], "--", &argv[0]);
 667         } else {
 668                 /* The user didn't specify a command; give them help */
 669                 commit_pager_choice();
 670                 printf("usage: %s\n\n", git_usage_string);
 671                 list_common_cmds_help();
 672                 printf("\n%s\n", _(git_more_info_string));
 673                 exit(1);
 674         }
 675         cmd = argv[0];
 676
 677         /*
 678          * We use PATH to find git commands, but we prepend some higher
 679          * precedence paths: the "--exec-path" option, the GIT_EXEC_PATH
 680          * environment, and the $(gitexecdir) from the Makefile at build
 681          * time.
 682          */
 683         setup_path();
 684
 685         while (1) {
 686                 int was_alias = run_argv(&argc, &argv);
 687                 if (errno != ENOENT)
 688                         break;
 689                 if (was_alias) {
 690                         fprintf(stderr, "Expansion of alias '%s' failed; "
 691                                 "'%s' is not a git command\n",
 692                                 cmd, argv[0]);
 693                         exit(1);
 694                 }
 695                 if (!done_help) {
 696                         cmd = argv[0] = help_unknown_cmd(cmd);
 697                         done_help = 1;
 698                 } else
 699                         break;
 700         }
 701
 702         fprintf(stderr, "Failed to run command '%s': %s\n",
 703                 cmd, strerror(errno));
 704
 705         return 1;
 706 }