git.con commit run-command: don't warn on SIGPIPE deaths (ac78663)
   1#include "builtin.h"
   2#include "exec_cmd.h"
   3#include "help.h"
   4#include "run-command.h"
   5
   6const 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
  13const 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
  18static struct startup_info git_startup_info;
  19static int use_pager = -1;
  20static char *orig_cwd;
  21static const char *env_names[] = {
  22        GIT_DIR_ENVIRONMENT,
  23        GIT_WORK_TREE_ENVIRONMENT,
  24        GIT_IMPLICIT_WORK_TREE_ENVIRONMENT,
  25        GIT_PREFIX_ENVIRONMENT
  26};
  27static char *orig_env[4];
  28static int saved_env_before_alias;
  29
  30static void save_env_before_alias(void)
  31{
  32        int i;
  33        if (saved_env_before_alias)
  34                return;
  35        saved_env_before_alias = 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
  44static void restore_env(int external_alias)
  45{
  46        int i;
  47        if (!external_alias && 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 (external_alias &&
  52                    !strcmp(env_names[i], GIT_PREFIX_ENVIRONMENT))
  53                        continue;
  54                if (orig_env[i])
  55                        setenv(env_names[i], orig_env[i], 1);
  56                else
  57                        unsetenv(env_names[i]);
  58        }
  59}
  60
  61static void commit_pager_choice(void) {
  62        switch (use_pager) {
  63        case 0:
  64                setenv("GIT_PAGER", "cat", 1);
  65                break;
  66        case 1:
  67                setup_pager();
  68                break;
  69        default:
  70                break;
  71        }
  72}
  73
  74static int handle_options(const char ***argv, int *argc, int *envchanged)
  75{
  76        const char **orig_argv = *argv;
  77
  78        while (*argc > 0) {
  79                const char *cmd = (*argv)[0];
  80                if (cmd[0] != '-')
  81                        break;
  82
  83                /*
  84                 * For legacy reasons, the "version" and "help"
  85                 * commands can be written with "--" prepended
  86                 * to make them look like flags.
  87                 */
  88                if (!strcmp(cmd, "--help") || !strcmp(cmd, "--version"))
  89                        break;
  90
  91                /*
  92                 * Check remaining flags.
  93                 */
  94                if (skip_prefix(cmd, "--exec-path", &cmd)) {
  95                        if (*cmd == '=')
  96                                git_set_argv_exec_path(cmd + 1);
  97                        else {
  98                                puts(git_exec_path());
  99                                exit(0);
 100                        }
 101                } else if (!strcmp(cmd, "--html-path")) {
 102                        puts(system_path(GIT_HTML_PATH));
 103                        exit(0);
 104                } else if (!strcmp(cmd, "--man-path")) {
 105                        puts(system_path(GIT_MAN_PATH));
 106                        exit(0);
 107                } else if (!strcmp(cmd, "--info-path")) {
 108                        puts(system_path(GIT_INFO_PATH));
 109                        exit(0);
 110                } else if (!strcmp(cmd, "-p") || !strcmp(cmd, "--paginate")) {
 111                        use_pager = 1;
 112                } else if (!strcmp(cmd, "--no-pager")) {
 113                        use_pager = 0;
 114                        if (envchanged)
 115                                *envchanged = 1;
 116                } else if (!strcmp(cmd, "--no-replace-objects")) {
 117                        check_replace_refs = 0;
 118                        setenv(NO_REPLACE_OBJECTS_ENVIRONMENT, "1", 1);
 119                        if (envchanged)
 120                                *envchanged = 1;
 121                } else if (!strcmp(cmd, "--git-dir")) {
 122                        if (*argc < 2) {
 123                                fprintf(stderr, "No directory given for --git-dir.\n" );
 124                                usage(git_usage_string);
 125                        }
 126                        setenv(GIT_DIR_ENVIRONMENT, (*argv)[1], 1);
 127                        if (envchanged)
 128                                *envchanged = 1;
 129                        (*argv)++;
 130                        (*argc)--;
 131                } else if (skip_prefix(cmd, "--git-dir=", &cmd)) {
 132                        setenv(GIT_DIR_ENVIRONMENT, cmd, 1);
 133                        if (envchanged)
 134                                *envchanged = 1;
 135                } else if (!strcmp(cmd, "--namespace")) {
 136                        if (*argc < 2) {
 137                                fprintf(stderr, "No namespace given for --namespace.\n" );
 138                                usage(git_usage_string);
 139                        }
 140                        setenv(GIT_NAMESPACE_ENVIRONMENT, (*argv)[1], 1);
 141                        if (envchanged)
 142                                *envchanged = 1;
 143                        (*argv)++;
 144                        (*argc)--;
 145                } else if (skip_prefix(cmd, "--namespace=", &cmd)) {
 146                        setenv(GIT_NAMESPACE_ENVIRONMENT, cmd, 1);
 147                        if (envchanged)
 148                                *envchanged = 1;
 149                } else if (!strcmp(cmd, "--work-tree")) {
 150                        if (*argc < 2) {
 151                                fprintf(stderr, "No directory given for --work-tree.\n" );
 152                                usage(git_usage_string);
 153                        }
 154                        setenv(GIT_WORK_TREE_ENVIRONMENT, (*argv)[1], 1);
 155                        if (envchanged)
 156                                *envchanged = 1;
 157                        (*argv)++;
 158                        (*argc)--;
 159                } else if (skip_prefix(cmd, "--work-tree=", &cmd)) {
 160                        setenv(GIT_WORK_TREE_ENVIRONMENT, cmd, 1);
 161                        if (envchanged)
 162                                *envchanged = 1;
 163                } else if (!strcmp(cmd, "--bare")) {
 164                        char *cwd = xgetcwd();
 165                        is_bare_repository_cfg = 1;
 166                        setenv(GIT_DIR_ENVIRONMENT, cwd, 0);
 167                        free(cwd);
 168                        setenv(GIT_IMPLICIT_WORK_TREE_ENVIRONMENT, "0", 1);
 169                        if (envchanged)
 170                                *envchanged = 1;
 171                } else if (!strcmp(cmd, "-c")) {
 172                        if (*argc < 2) {
 173                                fprintf(stderr, "-c expects a configuration string\n" );
 174                                usage(git_usage_string);
 175                        }
 176                        git_config_push_parameter((*argv)[1]);
 177                        (*argv)++;
 178                        (*argc)--;
 179                } else if (!strcmp(cmd, "--literal-pathspecs")) {
 180                        setenv(GIT_LITERAL_PATHSPECS_ENVIRONMENT, "1", 1);
 181                        if (envchanged)
 182                                *envchanged = 1;
 183                } else if (!strcmp(cmd, "--no-literal-pathspecs")) {
 184                        setenv(GIT_LITERAL_PATHSPECS_ENVIRONMENT, "0", 1);
 185                        if (envchanged)
 186                                *envchanged = 1;
 187                } else if (!strcmp(cmd, "--glob-pathspecs")) {
 188                        setenv(GIT_GLOB_PATHSPECS_ENVIRONMENT, "1", 1);
 189                        if (envchanged)
 190                                *envchanged = 1;
 191                } else if (!strcmp(cmd, "--noglob-pathspecs")) {
 192                        setenv(GIT_NOGLOB_PATHSPECS_ENVIRONMENT, "1", 1);
 193                        if (envchanged)
 194                                *envchanged = 1;
 195                } else if (!strcmp(cmd, "--icase-pathspecs")) {
 196                        setenv(GIT_ICASE_PATHSPECS_ENVIRONMENT, "1", 1);
 197                        if (envchanged)
 198                                *envchanged = 1;
 199                } else if (!strcmp(cmd, "--shallow-file")) {
 200                        (*argv)++;
 201                        (*argc)--;
 202                        set_alternate_shallow_file((*argv)[0], 1);
 203                        if (envchanged)
 204                                *envchanged = 1;
 205                } else if (!strcmp(cmd, "-C")) {
 206                        if (*argc < 2) {
 207                                fprintf(stderr, "No directory given for -C.\n" );
 208                                usage(git_usage_string);
 209                        }
 210                        if ((*argv)[1][0]) {
 211                                if (chdir((*argv)[1]))
 212                                        die_errno("Cannot change to '%s'", (*argv)[1]);
 213                                if (envchanged)
 214                                        *envchanged = 1;
 215                        }
 216                        (*argv)++;
 217                        (*argc)--;
 218                } else {
 219                        fprintf(stderr, "Unknown option: %s\n", cmd);
 220                        usage(git_usage_string);
 221                }
 222
 223                (*argv)++;
 224                (*argc)--;
 225        }
 226        return (*argv) - orig_argv;
 227}
 228
 229static int handle_alias(int *argcp, const char ***argv)
 230{
 231        int envchanged = 0, ret = 0, saved_errno = errno;
 232        int count, option_count;
 233        const char **new_argv;
 234        const char *alias_command;
 235        char *alias_string;
 236        int unused_nongit;
 237
 238        save_env_before_alias();
 239        setup_git_directory_gently(&unused_nongit);
 240
 241        alias_command = (*argv)[0];
 242        alias_string = alias_lookup(alias_command);
 243        if (alias_string) {
 244                if (alias_string[0] == '!') {
 245                        const char **alias_argv;
 246                        int argc = *argcp, i;
 247
 248                        commit_pager_choice();
 249                        restore_env(1);
 250
 251                        /* build alias_argv */
 252                        alias_argv = xmalloc(sizeof(*alias_argv) * (argc + 1));
 253                        alias_argv[0] = alias_string + 1;
 254                        for (i = 1; i < argc; ++i)
 255                                alias_argv[i] = (*argv)[i];
 256                        alias_argv[argc] = NULL;
 257
 258                        ret = run_command_v_opt(alias_argv, RUN_USING_SHELL);
 259                        if (ret >= 0)   /* normal exit */
 260                                exit(ret);
 261
 262                        die_errno("While expanding alias '%s': '%s'",
 263                            alias_command, alias_string + 1);
 264                }
 265                count = split_cmdline(alias_string, &new_argv);
 266                if (count < 0)
 267                        die("Bad alias.%s string: %s", alias_command,
 268                            split_cmdline_strerror(count));
 269                option_count = handle_options(&new_argv, &count, &envchanged);
 270                if (envchanged)
 271                        die("alias '%s' changes environment variables\n"
 272                                 "You can use '!git' in the alias to do this.",
 273                                 alias_command);
 274                memmove(new_argv - option_count, new_argv,
 275                                count * sizeof(char *));
 276                new_argv -= option_count;
 277
 278                if (count < 1)
 279                        die("empty alias for %s", alias_command);
 280
 281                if (!strcmp(alias_command, new_argv[0]))
 282                        die("recursive alias: %s", alias_command);
 283
 284                trace_argv_printf(new_argv,
 285                                  "trace: alias expansion: %s =>",
 286                                  alias_command);
 287
 288                REALLOC_ARRAY(new_argv, count + *argcp);
 289                /* insert after command name */
 290                memcpy(new_argv + count, *argv + 1, sizeof(char *) * *argcp);
 291
 292                *argv = new_argv;
 293                *argcp += count - 1;
 294
 295                ret = 1;
 296        }
 297
 298        restore_env(0);
 299
 300        errno = saved_errno;
 301
 302        return ret;
 303}
 304
 305#define RUN_SETUP               (1<<0)
 306#define RUN_SETUP_GENTLY        (1<<1)
 307#define USE_PAGER               (1<<2)
 308/*
 309 * require working tree to be present -- anything uses this needs
 310 * RUN_SETUP for reading from the configuration file.
 311 */
 312#define NEED_WORK_TREE          (1<<3)
 313
 314struct cmd_struct {
 315        const char *cmd;
 316        int (*fn)(int, const char **, const char *);
 317        int option;
 318};
 319
 320static int run_builtin(struct cmd_struct *p, int argc, const char **argv)
 321{
 322        int status, help;
 323        struct stat st;
 324        const char *prefix;
 325
 326        prefix = NULL;
 327        help = argc == 2 && !strcmp(argv[1], "-h");
 328        if (!help) {
 329                if (p->option & RUN_SETUP)
 330                        prefix = setup_git_directory();
 331                else if (p->option & RUN_SETUP_GENTLY) {
 332                        int nongit_ok;
 333                        prefix = setup_git_directory_gently(&nongit_ok);
 334                }
 335
 336                if (use_pager == -1 && p->option & (RUN_SETUP | RUN_SETUP_GENTLY))
 337                        use_pager = check_pager_config(p->cmd);
 338                if (use_pager == -1 && p->option & USE_PAGER)
 339                        use_pager = 1;
 340
 341                if ((p->option & (RUN_SETUP | RUN_SETUP_GENTLY)) &&
 342                    startup_info->have_repository) /* get_git_dir() may set up repo, avoid that */
 343                        trace_repo_setup(prefix);
 344        }
 345        commit_pager_choice();
 346
 347        if (!help && p->option & NEED_WORK_TREE)
 348                setup_work_tree();
 349
 350        trace_argv_printf(argv, "trace: built-in: git");
 351
 352        status = p->fn(argc, argv, prefix);
 353        if (status)
 354                return status;
 355
 356        /* Somebody closed stdout? */
 357        if (fstat(fileno(stdout), &st))
 358                return 0;
 359        /* Ignore write errors for pipes and sockets.. */
 360        if (S_ISFIFO(st.st_mode) || S_ISSOCK(st.st_mode))
 361                return 0;
 362
 363        /* Check for ENOSPC and EIO errors.. */
 364        if (fflush(stdout))
 365                die_errno("write failure on standard output");
 366        if (ferror(stdout))
 367                die("unknown write failure on standard output");
 368        if (fclose(stdout))
 369                die_errno("close failed on standard output");
 370        return 0;
 371}
 372
 373static struct cmd_struct commands[] = {
 374        { "add", cmd_add, RUN_SETUP | NEED_WORK_TREE },
 375        { "annotate", cmd_annotate, RUN_SETUP },
 376        { "apply", cmd_apply, RUN_SETUP_GENTLY },
 377        { "archive", cmd_archive },
 378        { "bisect--helper", cmd_bisect__helper, RUN_SETUP },
 379        { "blame", cmd_blame, RUN_SETUP },
 380        { "branch", cmd_branch, RUN_SETUP },
 381        { "bundle", cmd_bundle, RUN_SETUP_GENTLY },
 382        { "cat-file", cmd_cat_file, RUN_SETUP },
 383        { "check-attr", cmd_check_attr, RUN_SETUP },
 384        { "check-ignore", cmd_check_ignore, RUN_SETUP | NEED_WORK_TREE },
 385        { "check-mailmap", cmd_check_mailmap, RUN_SETUP },
 386        { "check-ref-format", cmd_check_ref_format },
 387        { "checkout", cmd_checkout, RUN_SETUP | NEED_WORK_TREE },
 388        { "checkout-index", cmd_checkout_index,
 389                RUN_SETUP | NEED_WORK_TREE},
 390        { "cherry", cmd_cherry, RUN_SETUP },
 391        { "cherry-pick", cmd_cherry_pick, RUN_SETUP | NEED_WORK_TREE },
 392        { "clean", cmd_clean, RUN_SETUP | NEED_WORK_TREE },
 393        { "clone", cmd_clone },
 394        { "column", cmd_column, RUN_SETUP_GENTLY },
 395        { "commit", cmd_commit, RUN_SETUP | NEED_WORK_TREE },
 396        { "commit-tree", cmd_commit_tree, RUN_SETUP },
 397        { "config", cmd_config, RUN_SETUP_GENTLY },
 398        { "count-objects", cmd_count_objects, RUN_SETUP },
 399        { "credential", cmd_credential, RUN_SETUP_GENTLY },
 400        { "describe", cmd_describe, RUN_SETUP },
 401        { "diff", cmd_diff },
 402        { "diff-files", cmd_diff_files, RUN_SETUP | NEED_WORK_TREE },
 403        { "diff-index", cmd_diff_index, RUN_SETUP },
 404        { "diff-tree", cmd_diff_tree, RUN_SETUP },
 405        { "fast-export", cmd_fast_export, RUN_SETUP },
 406        { "fetch", cmd_fetch, RUN_SETUP },
 407        { "fetch-pack", cmd_fetch_pack, RUN_SETUP },
 408        { "fmt-merge-msg", cmd_fmt_merge_msg, RUN_SETUP },
 409        { "for-each-ref", cmd_for_each_ref, RUN_SETUP },
 410        { "format-patch", cmd_format_patch, RUN_SETUP },
 411        { "fsck", cmd_fsck, RUN_SETUP },
 412        { "fsck-objects", cmd_fsck, RUN_SETUP },
 413        { "gc", cmd_gc, RUN_SETUP },
 414        { "get-tar-commit-id", cmd_get_tar_commit_id },
 415        { "grep", cmd_grep, RUN_SETUP_GENTLY },
 416        { "hash-object", cmd_hash_object },
 417        { "help", cmd_help },
 418        { "index-pack", cmd_index_pack, RUN_SETUP_GENTLY },
 419        { "init", cmd_init_db },
 420        { "init-db", cmd_init_db },
 421        { "interpret-trailers", cmd_interpret_trailers, RUN_SETUP },
 422        { "log", cmd_log, RUN_SETUP },
 423        { "ls-files", cmd_ls_files, RUN_SETUP },
 424        { "ls-remote", cmd_ls_remote, RUN_SETUP_GENTLY },
 425        { "ls-tree", cmd_ls_tree, RUN_SETUP },
 426        { "mailinfo", cmd_mailinfo },
 427        { "mailsplit", cmd_mailsplit },
 428        { "merge", cmd_merge, RUN_SETUP | NEED_WORK_TREE },
 429        { "merge-base", cmd_merge_base, RUN_SETUP },
 430        { "merge-file", cmd_merge_file, RUN_SETUP_GENTLY },
 431        { "merge-index", cmd_merge_index, RUN_SETUP },
 432        { "merge-ours", cmd_merge_ours, RUN_SETUP },
 433        { "merge-recursive", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE },
 434        { "merge-recursive-ours", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE },
 435        { "merge-recursive-theirs", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE },
 436        { "merge-subtree", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE },
 437        { "merge-tree", cmd_merge_tree, RUN_SETUP },
 438        { "mktag", cmd_mktag, RUN_SETUP },
 439        { "mktree", cmd_mktree, RUN_SETUP },
 440        { "mv", cmd_mv, RUN_SETUP | NEED_WORK_TREE },
 441        { "name-rev", cmd_name_rev, RUN_SETUP },
 442        { "notes", cmd_notes, RUN_SETUP },
 443        { "pack-objects", cmd_pack_objects, RUN_SETUP },
 444        { "pack-redundant", cmd_pack_redundant, RUN_SETUP },
 445        { "pack-refs", cmd_pack_refs, RUN_SETUP },
 446        { "patch-id", cmd_patch_id },
 447        { "pickaxe", cmd_blame, RUN_SETUP },
 448        { "prune", cmd_prune, RUN_SETUP },
 449        { "prune-packed", cmd_prune_packed, RUN_SETUP },
 450        { "push", cmd_push, RUN_SETUP },
 451        { "read-tree", cmd_read_tree, RUN_SETUP },
 452        { "receive-pack", cmd_receive_pack },
 453        { "reflog", cmd_reflog, RUN_SETUP },
 454        { "remote", cmd_remote, RUN_SETUP },
 455        { "remote-ext", cmd_remote_ext },
 456        { "remote-fd", cmd_remote_fd },
 457        { "repack", cmd_repack, RUN_SETUP },
 458        { "replace", cmd_replace, RUN_SETUP },
 459        { "rerere", cmd_rerere, RUN_SETUP },
 460        { "reset", cmd_reset, RUN_SETUP },
 461        { "rev-list", cmd_rev_list, RUN_SETUP },
 462        { "rev-parse", cmd_rev_parse },
 463        { "revert", cmd_revert, RUN_SETUP | NEED_WORK_TREE },
 464        { "rm", cmd_rm, RUN_SETUP },
 465        { "send-pack", cmd_send_pack, RUN_SETUP },
 466        { "shortlog", cmd_shortlog, RUN_SETUP_GENTLY | USE_PAGER },
 467        { "show", cmd_show, RUN_SETUP },
 468        { "show-branch", cmd_show_branch, RUN_SETUP },
 469        { "show-ref", cmd_show_ref, RUN_SETUP },
 470        { "stage", cmd_add, RUN_SETUP | NEED_WORK_TREE },
 471        { "status", cmd_status, RUN_SETUP | NEED_WORK_TREE },
 472        { "stripspace", cmd_stripspace },
 473        { "symbolic-ref", cmd_symbolic_ref, RUN_SETUP },
 474        { "tag", cmd_tag, RUN_SETUP },
 475        { "unpack-file", cmd_unpack_file, RUN_SETUP },
 476        { "unpack-objects", cmd_unpack_objects, RUN_SETUP },
 477        { "update-index", cmd_update_index, RUN_SETUP },
 478        { "update-ref", cmd_update_ref, RUN_SETUP },
 479        { "update-server-info", cmd_update_server_info, RUN_SETUP },
 480        { "upload-archive", cmd_upload_archive },
 481        { "upload-archive--writer", cmd_upload_archive_writer },
 482        { "var", cmd_var, RUN_SETUP_GENTLY },
 483        { "verify-commit", cmd_verify_commit, RUN_SETUP },
 484        { "verify-pack", cmd_verify_pack },
 485        { "verify-tag", cmd_verify_tag, RUN_SETUP },
 486        { "version", cmd_version },
 487        { "whatchanged", cmd_whatchanged, RUN_SETUP },
 488        { "worktree", cmd_worktree, RUN_SETUP },
 489        { "write-tree", cmd_write_tree, RUN_SETUP },
 490};
 491
 492static struct cmd_struct *get_builtin(const char *s)
 493{
 494        int i;
 495        for (i = 0; i < ARRAY_SIZE(commands); i++) {
 496                struct cmd_struct *p = commands + i;
 497                if (!strcmp(s, p->cmd))
 498                        return p;
 499        }
 500        return NULL;
 501}
 502
 503int is_builtin(const char *s)
 504{
 505        return !!get_builtin(s);
 506}
 507
 508static void handle_builtin(int argc, const char **argv)
 509{
 510        const char *cmd = argv[0];
 511        int i;
 512        static const char ext[] = STRIP_EXTENSION;
 513        struct cmd_struct *builtin;
 514
 515        if (sizeof(ext) > 1) {
 516                i = strlen(argv[0]) - strlen(ext);
 517                if (i > 0 && !strcmp(argv[0] + i, ext)) {
 518                        char *argv0 = xstrdup(argv[0]);
 519                        argv[0] = cmd = argv0;
 520                        argv0[i] = '\0';
 521                }
 522        }
 523
 524        /* Turn "git cmd --help" into "git help cmd" */
 525        if (argc > 1 && !strcmp(argv[1], "--help")) {
 526                argv[1] = argv[0];
 527                argv[0] = cmd = "help";
 528        }
 529
 530        builtin = get_builtin(cmd);
 531        if (builtin) {
 532                /*
 533                 * XXX: if we can figure out cases where it is _safe_
 534                 * to do, we can avoid spawning a new process when
 535                 * saved_env_before_alias is true
 536                 * (i.e. setup_git_dir* has been run once)
 537                 */
 538                if (!saved_env_before_alias)
 539                        exit(run_builtin(builtin, argc, argv));
 540        }
 541}
 542
 543static void execv_dashed_external(const char **argv)
 544{
 545        struct strbuf cmd = STRBUF_INIT;
 546        const char *tmp;
 547        int status;
 548
 549        if (use_pager == -1)
 550                use_pager = check_pager_config(argv[0]);
 551        commit_pager_choice();
 552
 553        strbuf_addf(&cmd, "git-%s", argv[0]);
 554
 555        /*
 556         * argv[0] must be the git command, but the argv array
 557         * belongs to the caller, and may be reused in
 558         * subsequent loop iterations. Save argv[0] and
 559         * restore it on error.
 560         */
 561        tmp = argv[0];
 562        argv[0] = cmd.buf;
 563
 564        trace_argv_printf(argv, "trace: exec:");
 565
 566        /*
 567         * if we fail because the command is not found, it is
 568         * OK to return. Otherwise, we just pass along the status code.
 569         */
 570        status = run_command_v_opt(argv, RUN_SILENT_EXEC_FAILURE | RUN_CLEAN_ON_EXIT);
 571        if (status >= 0 || errno != ENOENT)
 572                exit(status);
 573
 574        argv[0] = tmp;
 575
 576        strbuf_release(&cmd);
 577}
 578
 579static int run_argv(int *argcp, const char ***argv)
 580{
 581        int done_alias = 0;
 582
 583        while (1) {
 584                /* See if it's a builtin */
 585                handle_builtin(*argcp, *argv);
 586
 587                /* .. then try the external ones */
 588                execv_dashed_external(*argv);
 589
 590                /* It could be an alias -- this works around the insanity
 591                 * of overriding "git log" with "git show" by having
 592                 * alias.log = show
 593                 */
 594                if (done_alias)
 595                        break;
 596                if (!handle_alias(argcp, argv))
 597                        break;
 598                done_alias = 1;
 599        }
 600
 601        return done_alias;
 602}
 603
 604/*
 605 * Many parts of Git have subprograms communicate via pipe, expect the
 606 * upstream of a pipe to die with SIGPIPE when the downstream of a
 607 * pipe does not need to read all that is written.  Some third-party
 608 * programs that ignore or block SIGPIPE for their own reason forget
 609 * to restore SIGPIPE handling to the default before spawning Git and
 610 * break this carefully orchestrated machinery.
 611 *
 612 * Restore the way SIGPIPE is handled to default, which is what we
 613 * expect.
 614 */
 615static void restore_sigpipe_to_default(void)
 616{
 617        sigset_t unblock;
 618
 619        sigemptyset(&unblock);
 620        sigaddset(&unblock, SIGPIPE);
 621        sigprocmask(SIG_UNBLOCK, &unblock, NULL);
 622        signal(SIGPIPE, SIG_DFL);
 623}
 624
 625int main(int argc, char **av)
 626{
 627        const char **argv = (const char **) av;
 628        const char *cmd;
 629        int done_help = 0;
 630
 631        startup_info = &git_startup_info;
 632
 633        cmd = git_extract_argv0_path(argv[0]);
 634        if (!cmd)
 635                cmd = "git-help";
 636
 637        /*
 638         * Always open file descriptors 0/1/2 to avoid clobbering files
 639         * in die().  It also avoids messing up when the pipes are dup'ed
 640         * onto stdin/stdout/stderr in the child processes we spawn.
 641         */
 642        sanitize_stdfds();
 643
 644        restore_sigpipe_to_default();
 645
 646        git_setup_gettext();
 647
 648        trace_command_performance(argv);
 649
 650        /*
 651         * "git-xxxx" is the same as "git xxxx", but we obviously:
 652         *
 653         *  - cannot take flags in between the "git" and the "xxxx".
 654         *  - cannot execute it externally (since it would just do
 655         *    the same thing over again)
 656         *
 657         * So we just directly call the builtin handler, and die if
 658         * that one cannot handle it.
 659         */
 660        if (skip_prefix(cmd, "git-", &cmd)) {
 661                argv[0] = cmd;
 662                handle_builtin(argc, argv);
 663                die("cannot handle %s as a builtin", cmd);
 664        }
 665
 666        /* Look for flags.. */
 667        argv++;
 668        argc--;
 669        handle_options(&argv, &argc, NULL);
 670        if (argc > 0) {
 671                /* translate --help and --version into commands */
 672                skip_prefix(argv[0], "--", &argv[0]);
 673        } else {
 674                /* The user didn't specify a command; give them help */
 675                commit_pager_choice();
 676                printf("usage: %s\n\n", git_usage_string);
 677                list_common_cmds_help();
 678                printf("\n%s\n", _(git_more_info_string));
 679                exit(1);
 680        }
 681        cmd = argv[0];
 682
 683        /*
 684         * We use PATH to find git commands, but we prepend some higher
 685         * precedence paths: the "--exec-path" option, the GIT_EXEC_PATH
 686         * environment, and the $(gitexecdir) from the Makefile at build
 687         * time.
 688         */
 689        setup_path();
 690
 691        while (1) {
 692                int was_alias = run_argv(&argc, &argv);
 693                if (errno != ENOENT)
 694                        break;
 695                if (was_alias) {
 696                        fprintf(stderr, "Expansion of alias '%s' failed; "
 697                                "'%s' is not a git command\n",
 698                                cmd, argv[0]);
 699                        exit(1);
 700                }
 701                if (!done_help) {
 702                        cmd = argv[0] = help_unknown_cmd(cmd);
 703                        done_help = 1;
 704                } else
 705                        break;
 706        }
 707
 708        fprintf(stderr, "Failed to run command '%s': %s\n",
 709                cmd, strerror(errno));
 710
 711        return 1;
 712}