Andrew's git / gitweb.git / git.c
?
git.con commit Merge branch 'master' of https://github.com/vnwildman/git (103ee5c)
   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 save_restore_env_balance;
  29
  30static void save_env_before_alias(void)
  31{
  32        int i;
  33
  34        assert(save_restore_env_balance == 0);
  35        save_restore_env_balance = 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
  48        assert(save_restore_env_balance == 1);
  49        save_restore_env_balance = 0;
  50        if (!external_alias && orig_cwd && chdir(orig_cwd))
  51                die_errno("could not move to %s", orig_cwd);
  52        free(orig_cwd);
  53        for (i = 0; i < ARRAY_SIZE(env_names); i++) {
  54                if (external_alias &&
  55                    !strcmp(env_names[i], GIT_PREFIX_ENVIRONMENT))
  56                        continue;
  57                if (orig_env[i]) {
  58                        setenv(env_names[i], orig_env[i], 1);
  59                        free(orig_env[i]);
  60                } else {
  61                        unsetenv(env_names[i]);
  62                }
  63        }
  64}
  65
  66static void commit_pager_choice(void) {
  67        switch (use_pager) {
  68        case 0:
  69                setenv("GIT_PAGER", "cat", 1);
  70                break;
  71        case 1:
  72                setup_pager();
  73                break;
  74        default:
  75                break;
  76        }
  77}
  78
  79static int handle_options(const char ***argv, int *argc, int *envchanged)
  80{
  81        const char **orig_argv = *argv;
  82
  83        while (*argc > 0) {
  84                const char *cmd = (*argv)[0];
  85                if (cmd[0] != '-')
  86                        break;
  87
  88                /*
  89                 * For legacy reasons, the "version" and "help"
  90                 * commands can be written with "--" prepended
  91                 * to make them look like flags.
  92                 */
  93                if (!strcmp(cmd, "--help") || !strcmp(cmd, "--version"))
  94                        break;
  95
  96                /*
  97                 * Check remaining flags.
  98                 */
  99                if (skip_prefix(cmd, "--exec-path", &cmd)) {
 100                        if (*cmd == '=')
 101                                git_set_argv_exec_path(cmd + 1);
 102                        else {
 103                                puts(git_exec_path());
 104                                exit(0);
 105                        }
 106                } else if (!strcmp(cmd, "--html-path")) {
 107                        puts(system_path(GIT_HTML_PATH));
 108                        exit(0);
 109                } else if (!strcmp(cmd, "--man-path")) {
 110                        puts(system_path(GIT_MAN_PATH));
 111                        exit(0);
 112                } else if (!strcmp(cmd, "--info-path")) {
 113                        puts(system_path(GIT_INFO_PATH));
 114                        exit(0);
 115                } else if (!strcmp(cmd, "-p") || !strcmp(cmd, "--paginate")) {
 116                        use_pager = 1;
 117                } else if (!strcmp(cmd, "--no-pager")) {
 118                        use_pager = 0;
 119                        if (envchanged)
 120                                *envchanged = 1;
 121                } else if (!strcmp(cmd, "--no-replace-objects")) {
 122                        check_replace_refs = 0;
 123                        setenv(NO_REPLACE_OBJECTS_ENVIRONMENT, "1", 1);
 124                        if (envchanged)
 125                                *envchanged = 1;
 126                } else if (!strcmp(cmd, "--git-dir")) {
 127                        if (*argc < 2) {
 128                                fprintf(stderr, "No directory given for --git-dir.\n" );
 129                                usage(git_usage_string);
 130                        }
 131                        setenv(GIT_DIR_ENVIRONMENT, (*argv)[1], 1);
 132                        if (envchanged)
 133                                *envchanged = 1;
 134                        (*argv)++;
 135                        (*argc)--;
 136                } else if (skip_prefix(cmd, "--git-dir=", &cmd)) {
 137                        setenv(GIT_DIR_ENVIRONMENT, cmd, 1);
 138                        if (envchanged)
 139                                *envchanged = 1;
 140                } else if (!strcmp(cmd, "--namespace")) {
 141                        if (*argc < 2) {
 142                                fprintf(stderr, "No namespace given for --namespace.\n" );
 143                                usage(git_usage_string);
 144                        }
 145                        setenv(GIT_NAMESPACE_ENVIRONMENT, (*argv)[1], 1);
 146                        if (envchanged)
 147                                *envchanged = 1;
 148                        (*argv)++;
 149                        (*argc)--;
 150                } else if (skip_prefix(cmd, "--namespace=", &cmd)) {
 151                        setenv(GIT_NAMESPACE_ENVIRONMENT, cmd, 1);
 152                        if (envchanged)
 153                                *envchanged = 1;
 154                } else if (!strcmp(cmd, "--work-tree")) {
 155                        if (*argc < 2) {
 156                                fprintf(stderr, "No directory given for --work-tree.\n" );
 157                                usage(git_usage_string);
 158                        }
 159                        setenv(GIT_WORK_TREE_ENVIRONMENT, (*argv)[1], 1);
 160                        if (envchanged)
 161                                *envchanged = 1;
 162                        (*argv)++;
 163                        (*argc)--;
 164                } else if (skip_prefix(cmd, "--work-tree=", &cmd)) {
 165                        setenv(GIT_WORK_TREE_ENVIRONMENT, cmd, 1);
 166                        if (envchanged)
 167                                *envchanged = 1;
 168                } else if (!strcmp(cmd, "--bare")) {
 169                        char *cwd = xgetcwd();
 170                        is_bare_repository_cfg = 1;
 171                        setenv(GIT_DIR_ENVIRONMENT, cwd, 0);
 172                        free(cwd);
 173                        setenv(GIT_IMPLICIT_WORK_TREE_ENVIRONMENT, "0", 1);
 174                        if (envchanged)
 175                                *envchanged = 1;
 176                } else if (!strcmp(cmd, "-c")) {
 177                        if (*argc < 2) {
 178                                fprintf(stderr, "-c expects a configuration string\n" );
 179                                usage(git_usage_string);
 180                        }
 181                        git_config_push_parameter((*argv)[1]);
 182                        (*argv)++;
 183                        (*argc)--;
 184                } else if (!strcmp(cmd, "--literal-pathspecs")) {
 185                        setenv(GIT_LITERAL_PATHSPECS_ENVIRONMENT, "1", 1);
 186                        if (envchanged)
 187                                *envchanged = 1;
 188                } else if (!strcmp(cmd, "--no-literal-pathspecs")) {
 189                        setenv(GIT_LITERAL_PATHSPECS_ENVIRONMENT, "0", 1);
 190                        if (envchanged)
 191                                *envchanged = 1;
 192                } else if (!strcmp(cmd, "--glob-pathspecs")) {
 193                        setenv(GIT_GLOB_PATHSPECS_ENVIRONMENT, "1", 1);
 194                        if (envchanged)
 195                                *envchanged = 1;
 196                } else if (!strcmp(cmd, "--noglob-pathspecs")) {
 197                        setenv(GIT_NOGLOB_PATHSPECS_ENVIRONMENT, "1", 1);
 198                        if (envchanged)
 199                                *envchanged = 1;
 200                } else if (!strcmp(cmd, "--icase-pathspecs")) {
 201                        setenv(GIT_ICASE_PATHSPECS_ENVIRONMENT, "1", 1);
 202                        if (envchanged)
 203                                *envchanged = 1;
 204                } else if (!strcmp(cmd, "--shallow-file")) {
 205                        (*argv)++;
 206                        (*argc)--;
 207                        set_alternate_shallow_file((*argv)[0], 1);
 208                        if (envchanged)
 209                                *envchanged = 1;
 210                } else if (!strcmp(cmd, "-C")) {
 211                        if (*argc < 2) {
 212                                fprintf(stderr, "No directory given for -C.\n" );
 213                                usage(git_usage_string);
 214                        }
 215                        if ((*argv)[1][0]) {
 216                                if (chdir((*argv)[1]))
 217                                        die_errno("Cannot change to '%s'", (*argv)[1]);
 218                                if (envchanged)
 219                                        *envchanged = 1;
 220                        }
 221                        (*argv)++;
 222                        (*argc)--;
 223                } else {
 224                        fprintf(stderr, "Unknown option: %s\n", cmd);
 225                        usage(git_usage_string);
 226                }
 227
 228                (*argv)++;
 229                (*argc)--;
 230        }
 231        return (*argv) - orig_argv;
 232}
 233
 234static int handle_alias(int *argcp, const char ***argv)
 235{
 236        int envchanged = 0, ret = 0, saved_errno = errno;
 237        int count, option_count;
 238        const char **new_argv;
 239        const char *alias_command;
 240        char *alias_string;
 241        int unused_nongit;
 242
 243        save_env_before_alias();
 244        setup_git_directory_gently(&unused_nongit);
 245
 246        alias_command = (*argv)[0];
 247        alias_string = alias_lookup(alias_command);
 248        if (alias_string) {
 249                if (alias_string[0] == '!') {
 250                        struct child_process child = CHILD_PROCESS_INIT;
 251
 252                        commit_pager_choice();
 253                        restore_env(1);
 254
 255                        child.use_shell = 1;
 256                        argv_array_push(&child.args, alias_string + 1);
 257                        argv_array_pushv(&child.args, (*argv) + 1);
 258
 259                        ret = run_command(&child);
 260                        if (ret >= 0)   /* normal exit */
 261                                exit(ret);
 262
 263                        die_errno("While expanding alias '%s': '%s'",
 264                            alias_command, alias_string + 1);
 265                }
 266                count = split_cmdline(alias_string, &new_argv);
 267                if (count < 0)
 268                        die("Bad alias.%s string: %s", alias_command,
 269                            split_cmdline_strerror(count));
 270                option_count = handle_options(&new_argv, &count, &envchanged);
 271                if (envchanged)
 272                        die("alias '%s' changes environment variables\n"
 273                                 "You can use '!git' in the alias to do this.",
 274                                 alias_command);
 275                memmove(new_argv - option_count, new_argv,
 276                                count * sizeof(char *));
 277                new_argv -= option_count;
 278
 279                if (count < 1)
 280                        die("empty alias for %s", alias_command);
 281
 282                if (!strcmp(alias_command, new_argv[0]))
 283                        die("recursive alias: %s", alias_command);
 284
 285                trace_argv_printf(new_argv,
 286                                  "trace: alias expansion: %s =>",
 287                                  alias_command);
 288
 289                REALLOC_ARRAY(new_argv, count + *argcp);
 290                /* insert after command name */
 291                memcpy(new_argv + count, *argv + 1, sizeof(char *) * *argcp);
 292
 293                *argv = new_argv;
 294                *argcp += count - 1;
 295
 296                ret = 1;
 297        }
 298
 299        restore_env(0);
 300
 301        errno = saved_errno;
 302
 303        return ret;
 304}
 305
 306#define RUN_SETUP               (1<<0)
 307#define RUN_SETUP_GENTLY        (1<<1)
 308#define USE_PAGER               (1<<2)
 309/*
 310 * require working tree to be present -- anything uses this needs
 311 * RUN_SETUP for reading from the configuration file.
 312 */
 313#define NEED_WORK_TREE          (1<<3)
 314
 315struct cmd_struct {
 316        const char *cmd;
 317        int (*fn)(int, const char **, const char *);
 318        int option;
 319};
 320
 321static int run_builtin(struct cmd_struct *p, int argc, const char **argv)
 322{
 323        int status, help;
 324        struct stat st;
 325        const char *prefix;
 326
 327        prefix = NULL;
 328        help = argc == 2 && !strcmp(argv[1], "-h");
 329        if (!help) {
 330                if (p->option & RUN_SETUP)
 331                        prefix = setup_git_directory();
 332                else if (p->option & RUN_SETUP_GENTLY) {
 333                        int nongit_ok;
 334                        prefix = setup_git_directory_gently(&nongit_ok);
 335                }
 336
 337                if (use_pager == -1 && p->option & (RUN_SETUP | RUN_SETUP_GENTLY))
 338                        use_pager = check_pager_config(p->cmd);
 339                if (use_pager == -1 && p->option & USE_PAGER)
 340                        use_pager = 1;
 341
 342                if ((p->option & (RUN_SETUP | RUN_SETUP_GENTLY)) &&
 343                    startup_info->have_repository) /* get_git_dir() may set up repo, avoid that */
 344                        trace_repo_setup(prefix);
 345        }
 346        commit_pager_choice();
 347
 348        if (!help && p->option & NEED_WORK_TREE)
 349                setup_work_tree();
 350
 351        trace_argv_printf(argv, "trace: built-in: git");
 352
 353        status = p->fn(argc, argv, prefix);
 354        if (status)
 355                return status;
 356
 357        /* Somebody closed stdout? */
 358        if (fstat(fileno(stdout), &st))
 359                return 0;
 360        /* Ignore write errors for pipes and sockets.. */
 361        if (S_ISFIFO(st.st_mode) || S_ISSOCK(st.st_mode))
 362                return 0;
 363
 364        /* Check for ENOSPC and EIO errors.. */
 365        if (fflush(stdout))
 366                die_errno("write failure on standard output");
 367        if (ferror(stdout))
 368                die("unknown write failure on standard output");
 369        if (fclose(stdout))
 370                die_errno("close failed on standard output");
 371        return 0;
 372}
 373
 374static struct cmd_struct commands[] = {
 375        { "add", cmd_add, RUN_SETUP | NEED_WORK_TREE },
 376        { "am", cmd_am, RUN_SETUP | NEED_WORK_TREE },
 377        { "annotate", cmd_annotate, RUN_SETUP },
 378        { "apply", cmd_apply, RUN_SETUP_GENTLY },
 379        { "archive", cmd_archive },
 380        { "bisect--helper", cmd_bisect__helper, RUN_SETUP },
 381        { "blame", cmd_blame, RUN_SETUP },
 382        { "branch", cmd_branch, RUN_SETUP },
 383        { "bundle", cmd_bundle, RUN_SETUP_GENTLY },
 384        { "cat-file", cmd_cat_file, RUN_SETUP },
 385        { "check-attr", cmd_check_attr, RUN_SETUP },
 386        { "check-ignore", cmd_check_ignore, RUN_SETUP | NEED_WORK_TREE },
 387        { "check-mailmap", cmd_check_mailmap, RUN_SETUP },
 388        { "check-ref-format", cmd_check_ref_format },
 389        { "checkout", cmd_checkout, RUN_SETUP | NEED_WORK_TREE },
 390        { "checkout-index", cmd_checkout_index,
 391                RUN_SETUP | NEED_WORK_TREE},
 392        { "cherry", cmd_cherry, RUN_SETUP },
 393        { "cherry-pick", cmd_cherry_pick, RUN_SETUP | NEED_WORK_TREE },
 394        { "clean", cmd_clean, RUN_SETUP | NEED_WORK_TREE },
 395        { "clone", cmd_clone },
 396        { "column", cmd_column, RUN_SETUP_GENTLY },
 397        { "commit", cmd_commit, RUN_SETUP | NEED_WORK_TREE },
 398        { "commit-tree", cmd_commit_tree, RUN_SETUP },
 399        { "config", cmd_config, RUN_SETUP_GENTLY },
 400        { "count-objects", cmd_count_objects, RUN_SETUP },
 401        { "credential", cmd_credential, RUN_SETUP_GENTLY },
 402        { "describe", cmd_describe, RUN_SETUP },
 403        { "diff", cmd_diff },
 404        { "diff-files", cmd_diff_files, RUN_SETUP | NEED_WORK_TREE },
 405        { "diff-index", cmd_diff_index, RUN_SETUP },
 406        { "diff-tree", cmd_diff_tree, RUN_SETUP },
 407        { "fast-export", cmd_fast_export, RUN_SETUP },
 408        { "fetch", cmd_fetch, RUN_SETUP },
 409        { "fetch-pack", cmd_fetch_pack, RUN_SETUP },
 410        { "fmt-merge-msg", cmd_fmt_merge_msg, RUN_SETUP },
 411        { "for-each-ref", cmd_for_each_ref, RUN_SETUP },
 412        { "format-patch", cmd_format_patch, RUN_SETUP },
 413        { "fsck", cmd_fsck, RUN_SETUP },
 414        { "fsck-objects", cmd_fsck, RUN_SETUP },
 415        { "gc", cmd_gc, RUN_SETUP },
 416        { "get-tar-commit-id", cmd_get_tar_commit_id },
 417        { "grep", cmd_grep, RUN_SETUP_GENTLY },
 418        { "hash-object", cmd_hash_object },
 419        { "help", cmd_help },
 420        { "index-pack", cmd_index_pack, RUN_SETUP_GENTLY },
 421        { "init", cmd_init_db },
 422        { "init-db", cmd_init_db },
 423        { "interpret-trailers", cmd_interpret_trailers, RUN_SETUP_GENTLY },
 424        { "log", cmd_log, RUN_SETUP },
 425        { "ls-files", cmd_ls_files, RUN_SETUP },
 426        { "ls-remote", cmd_ls_remote, RUN_SETUP_GENTLY },
 427        { "ls-tree", cmd_ls_tree, RUN_SETUP },
 428        { "mailinfo", cmd_mailinfo },
 429        { "mailsplit", cmd_mailsplit },
 430        { "merge", cmd_merge, RUN_SETUP | NEED_WORK_TREE },
 431        { "merge-base", cmd_merge_base, RUN_SETUP },
 432        { "merge-file", cmd_merge_file, RUN_SETUP_GENTLY },
 433        { "merge-index", cmd_merge_index, RUN_SETUP },
 434        { "merge-ours", cmd_merge_ours, RUN_SETUP },
 435        { "merge-recursive", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE },
 436        { "merge-recursive-ours", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE },
 437        { "merge-recursive-theirs", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE },
 438        { "merge-subtree", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE },
 439        { "merge-tree", cmd_merge_tree, RUN_SETUP },
 440        { "mktag", cmd_mktag, RUN_SETUP },
 441        { "mktree", cmd_mktree, RUN_SETUP },
 442        { "mv", cmd_mv, RUN_SETUP | NEED_WORK_TREE },
 443        { "name-rev", cmd_name_rev, RUN_SETUP },
 444        { "notes", cmd_notes, RUN_SETUP },
 445        { "pack-objects", cmd_pack_objects, RUN_SETUP },
 446        { "pack-redundant", cmd_pack_redundant, RUN_SETUP },
 447        { "pack-refs", cmd_pack_refs, RUN_SETUP },
 448        { "patch-id", cmd_patch_id },
 449        { "pickaxe", cmd_blame, RUN_SETUP },
 450        { "prune", cmd_prune, RUN_SETUP },
 451        { "prune-packed", cmd_prune_packed, RUN_SETUP },
 452        { "pull", cmd_pull, RUN_SETUP | NEED_WORK_TREE },
 453        { "push", cmd_push, RUN_SETUP },
 454        { "read-tree", cmd_read_tree, RUN_SETUP },
 455        { "receive-pack", cmd_receive_pack },
 456        { "reflog", cmd_reflog, RUN_SETUP },
 457        { "remote", cmd_remote, RUN_SETUP },
 458        { "remote-ext", cmd_remote_ext },
 459        { "remote-fd", cmd_remote_fd },
 460        { "repack", cmd_repack, RUN_SETUP },
 461        { "replace", cmd_replace, RUN_SETUP },
 462        { "rerere", cmd_rerere, RUN_SETUP },
 463        { "reset", cmd_reset, RUN_SETUP },
 464        { "rev-list", cmd_rev_list, RUN_SETUP },
 465        { "rev-parse", cmd_rev_parse },
 466        { "revert", cmd_revert, RUN_SETUP | NEED_WORK_TREE },
 467        { "rm", cmd_rm, RUN_SETUP },
 468        { "send-pack", cmd_send_pack, RUN_SETUP },
 469        { "shortlog", cmd_shortlog, RUN_SETUP_GENTLY | USE_PAGER },
 470        { "show", cmd_show, RUN_SETUP },
 471        { "show-branch", cmd_show_branch, RUN_SETUP },
 472        { "show-ref", cmd_show_ref, RUN_SETUP },
 473        { "stage", cmd_add, RUN_SETUP | NEED_WORK_TREE },
 474        { "status", cmd_status, RUN_SETUP | NEED_WORK_TREE },
 475        { "stripspace", cmd_stripspace },
 476        { "submodule--helper", cmd_submodule__helper, RUN_SETUP },
 477        { "symbolic-ref", cmd_symbolic_ref, RUN_SETUP },
 478        { "tag", cmd_tag, RUN_SETUP },
 479        { "unpack-file", cmd_unpack_file, RUN_SETUP },
 480        { "unpack-objects", cmd_unpack_objects, RUN_SETUP },
 481        { "update-index", cmd_update_index, RUN_SETUP },
 482        { "update-ref", cmd_update_ref, RUN_SETUP },
 483        { "update-server-info", cmd_update_server_info, RUN_SETUP },
 484        { "upload-archive", cmd_upload_archive },
 485        { "upload-archive--writer", cmd_upload_archive_writer },
 486        { "var", cmd_var, RUN_SETUP_GENTLY },
 487        { "verify-commit", cmd_verify_commit, RUN_SETUP },
 488        { "verify-pack", cmd_verify_pack },
 489        { "verify-tag", cmd_verify_tag, RUN_SETUP },
 490        { "version", cmd_version },
 491        { "whatchanged", cmd_whatchanged, RUN_SETUP },
 492        { "worktree", cmd_worktree, RUN_SETUP },
 493        { "write-tree", cmd_write_tree, RUN_SETUP },
 494};
 495
 496static struct cmd_struct *get_builtin(const char *s)
 497{
 498        int i;
 499        for (i = 0; i < ARRAY_SIZE(commands); i++) {
 500                struct cmd_struct *p = commands + i;
 501                if (!strcmp(s, p->cmd))
 502                        return p;
 503        }
 504        return NULL;
 505}
 506
 507int is_builtin(const char *s)
 508{
 509        return !!get_builtin(s);
 510}
 511
 512#ifdef STRIP_EXTENSION
 513static void strip_extension(const char **argv)
 514{
 515        size_t len;
 516
 517        if (strip_suffix(argv[0], STRIP_EXTENSION, &len))
 518                argv[0] = xmemdupz(argv[0], len);
 519}
 520#else
 521#define strip_extension(cmd)
 522#endif
 523
 524static void handle_builtin(int argc, const char **argv)
 525{
 526        const char *cmd;
 527        struct cmd_struct *builtin;
 528
 529        strip_extension(argv);
 530        cmd = argv[0];
 531
 532        /* Turn "git cmd --help" into "git help cmd" */
 533        if (argc > 1 && !strcmp(argv[1], "--help")) {
 534                argv[1] = argv[0];
 535                argv[0] = cmd = "help";
 536        }
 537
 538        builtin = get_builtin(cmd);
 539        if (builtin)
 540                exit(run_builtin(builtin, argc, argv));
 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                /*
 585                 * If we tried alias and futzed with our environment,
 586                 * it no longer is safe to invoke builtins directly in
 587                 * general.  We have to spawn them as dashed externals.
 588                 *
 589                 * NEEDSWORK: if we can figure out cases
 590                 * where it is safe to do, we can avoid spawning a new
 591                 * process.
 592                 */
 593                if (!done_alias)
 594                        handle_builtin(*argcp, *argv);
 595
 596                /* .. then try the external ones */
 597                execv_dashed_external(*argv);
 598
 599                /* It could be an alias -- this works around the insanity
 600                 * of overriding "git log" with "git show" by having
 601                 * alias.log = show
 602                 */
 603                if (done_alias)
 604                        break;
 605                if (!handle_alias(argcp, argv))
 606                        break;
 607                done_alias = 1;
 608        }
 609
 610        return done_alias;
 611}
 612
 613/*
 614 * Many parts of Git have subprograms communicate via pipe, expect the
 615 * upstream of a pipe to die with SIGPIPE when the downstream of a
 616 * pipe does not need to read all that is written.  Some third-party
 617 * programs that ignore or block SIGPIPE for their own reason forget
 618 * to restore SIGPIPE handling to the default before spawning Git and
 619 * break this carefully orchestrated machinery.
 620 *
 621 * Restore the way SIGPIPE is handled to default, which is what we
 622 * expect.
 623 */
 624static void restore_sigpipe_to_default(void)
 625{
 626        sigset_t unblock;
 627
 628        sigemptyset(&unblock);
 629        sigaddset(&unblock, SIGPIPE);
 630        sigprocmask(SIG_UNBLOCK, &unblock, NULL);
 631        signal(SIGPIPE, SIG_DFL);
 632}
 633
 634int main(int argc, char **av)
 635{
 636        const char **argv = (const char **) av;
 637        const char *cmd;
 638        int done_help = 0;
 639
 640        startup_info = &git_startup_info;
 641
 642        cmd = git_extract_argv0_path(argv[0]);
 643        if (!cmd)
 644                cmd = "git-help";
 645
 646        /*
 647         * Always open file descriptors 0/1/2 to avoid clobbering files
 648         * in die().  It also avoids messing up when the pipes are dup'ed
 649         * onto stdin/stdout/stderr in the child processes we spawn.
 650         */
 651        sanitize_stdfds();
 652
 653        restore_sigpipe_to_default();
 654
 655        git_setup_gettext();
 656
 657        trace_command_performance(argv);
 658
 659        /*
 660         * "git-xxxx" is the same as "git xxxx", but we obviously:
 661         *
 662         *  - cannot take flags in between the "git" and the "xxxx".
 663         *  - cannot execute it externally (since it would just do
 664         *    the same thing over again)
 665         *
 666         * So we just directly call the builtin handler, and die if
 667         * that one cannot handle it.
 668         */
 669        if (skip_prefix(cmd, "git-", &cmd)) {
 670                argv[0] = cmd;
 671                handle_builtin(argc, argv);
 672                die("cannot handle %s as a builtin", cmd);
 673        }
 674
 675        /* Look for flags.. */
 676        argv++;
 677        argc--;
 678        handle_options(&argv, &argc, NULL);
 679        if (argc > 0) {
 680                /* translate --help and --version into commands */
 681                skip_prefix(argv[0], "--", &argv[0]);
 682        } else {
 683                /* The user didn't specify a command; give them help */
 684                commit_pager_choice();
 685                printf("usage: %s\n\n", git_usage_string);
 686                list_common_cmds_help();
 687                printf("\n%s\n", _(git_more_info_string));
 688                exit(1);
 689        }
 690        cmd = argv[0];
 691
 692        /*
 693         * We use PATH to find git commands, but we prepend some higher
 694         * precedence paths: the "--exec-path" option, the GIT_EXEC_PATH
 695         * environment, and the $(gitexecdir) from the Makefile at build
 696         * time.
 697         */
 698        setup_path();
 699
 700        while (1) {
 701                int was_alias = run_argv(&argc, &argv);
 702                if (errno != ENOENT)
 703                        break;
 704                if (was_alias) {
 705                        fprintf(stderr, "Expansion of alias '%s' failed; "
 706                                "'%s' is not a git command\n",
 707                                cmd, argv[0]);
 708                        exit(1);
 709                }
 710                if (!done_help) {
 711                        cmd = argv[0] = help_unknown_cmd(cmd);
 712                        done_help = 1;
 713                } else
 714                        break;
 715        }
 716
 717        fprintf(stderr, "Failed to run command '%s': %s\n",
 718                cmd, strerror(errno));
 719
 720        return 1;
 721}