Andrew's git / gitweb.git / git.c
?
git.con commit push: add a config option push.gpgSign for default signed pushes (68c757f)
   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_environment;
  29
  30static 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
  44static 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
  58static 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
  71static 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
 226static 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
 312struct cmd_struct {
 313        const char *cmd;
 314        int (*fn)(int, const char **, const char *);
 315        int option;
 316};
 317
 318static 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
 371static 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, 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
 489static 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
 500int is_builtin(const char *s)
 501{
 502        return !!get_builtin(s);
 503}
 504
 505static 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
 536static 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
 572static 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 */
 609static 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
 619int 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}