git.con commit Merge branch 'rs/ring-buffer-wraparound' into maint (f2ad912)
   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 int use_pager = -1;
  19static char *orig_cwd;
  20static const char *env_names[] = {
  21        GIT_DIR_ENVIRONMENT,
  22        GIT_WORK_TREE_ENVIRONMENT,
  23        GIT_IMPLICIT_WORK_TREE_ENVIRONMENT,
  24        GIT_PREFIX_ENVIRONMENT
  25};
  26static char *orig_env[4];
  27static int save_restore_env_balance;
  28
  29static void save_env_before_alias(void)
  30{
  31        int i;
  32
  33        assert(save_restore_env_balance == 0);
  34        save_restore_env_balance = 1;
  35        orig_cwd = xgetcwd();
  36        for (i = 0; i < ARRAY_SIZE(env_names); i++) {
  37                orig_env[i] = getenv(env_names[i]);
  38                orig_env[i] = xstrdup_or_null(orig_env[i]);
  39        }
  40}
  41
  42static void restore_env(int external_alias)
  43{
  44        int i;
  45
  46        assert(save_restore_env_balance == 1);
  47        save_restore_env_balance = 0;
  48        if (!external_alias && orig_cwd && chdir(orig_cwd))
  49                die_errno("could not move to %s", orig_cwd);
  50        free(orig_cwd);
  51        for (i = 0; i < ARRAY_SIZE(env_names); i++) {
  52                if (external_alias &&
  53                    !strcmp(env_names[i], GIT_PREFIX_ENVIRONMENT))
  54                        continue;
  55                if (orig_env[i]) {
  56                        setenv(env_names[i], orig_env[i], 1);
  57                        free(orig_env[i]);
  58                } else {
  59                        unsetenv(env_names[i]);
  60                }
  61        }
  62}
  63
  64static void commit_pager_choice(void) {
  65        switch (use_pager) {
  66        case 0:
  67                setenv("GIT_PAGER", "cat", 1);
  68                break;
  69        case 1:
  70                setup_pager();
  71                break;
  72        default:
  73                break;
  74        }
  75}
  76
  77static int handle_options(const char ***argv, int *argc, int *envchanged)
  78{
  79        const char **orig_argv = *argv;
  80
  81        while (*argc > 0) {
  82                const char *cmd = (*argv)[0];
  83                if (cmd[0] != '-')
  84                        break;
  85
  86                /*
  87                 * For legacy reasons, the "version" and "help"
  88                 * commands can be written with "--" prepended
  89                 * to make them look like flags.
  90                 */
  91                if (!strcmp(cmd, "--help") || !strcmp(cmd, "--version"))
  92                        break;
  93
  94                /*
  95                 * Check remaining flags.
  96                 */
  97                if (skip_prefix(cmd, "--exec-path", &cmd)) {
  98                        if (*cmd == '=')
  99                                git_set_argv_exec_path(cmd + 1);
 100                        else {
 101                                puts(git_exec_path());
 102                                exit(0);
 103                        }
 104                } else if (!strcmp(cmd, "--html-path")) {
 105                        puts(system_path(GIT_HTML_PATH));
 106                        exit(0);
 107                } else if (!strcmp(cmd, "--man-path")) {
 108                        puts(system_path(GIT_MAN_PATH));
 109                        exit(0);
 110                } else if (!strcmp(cmd, "--info-path")) {
 111                        puts(system_path(GIT_INFO_PATH));
 112                        exit(0);
 113                } else if (!strcmp(cmd, "-p") || !strcmp(cmd, "--paginate")) {
 114                        use_pager = 1;
 115                } else if (!strcmp(cmd, "--no-pager")) {
 116                        use_pager = 0;
 117                        if (envchanged)
 118                                *envchanged = 1;
 119                } else if (!strcmp(cmd, "--no-replace-objects")) {
 120                        check_replace_refs = 0;
 121                        setenv(NO_REPLACE_OBJECTS_ENVIRONMENT, "1", 1);
 122                        if (envchanged)
 123                                *envchanged = 1;
 124                } else if (!strcmp(cmd, "--git-dir")) {
 125                        if (*argc < 2) {
 126                                fprintf(stderr, "No directory given for --git-dir.\n" );
 127                                usage(git_usage_string);
 128                        }
 129                        setenv(GIT_DIR_ENVIRONMENT, (*argv)[1], 1);
 130                        if (envchanged)
 131                                *envchanged = 1;
 132                        (*argv)++;
 133                        (*argc)--;
 134                } else if (skip_prefix(cmd, "--git-dir=", &cmd)) {
 135                        setenv(GIT_DIR_ENVIRONMENT, cmd, 1);
 136                        if (envchanged)
 137                                *envchanged = 1;
 138                } else if (!strcmp(cmd, "--namespace")) {
 139                        if (*argc < 2) {
 140                                fprintf(stderr, "No namespace given for --namespace.\n" );
 141                                usage(git_usage_string);
 142                        }
 143                        setenv(GIT_NAMESPACE_ENVIRONMENT, (*argv)[1], 1);
 144                        if (envchanged)
 145                                *envchanged = 1;
 146                        (*argv)++;
 147                        (*argc)--;
 148                } else if (skip_prefix(cmd, "--namespace=", &cmd)) {
 149                        setenv(GIT_NAMESPACE_ENVIRONMENT, cmd, 1);
 150                        if (envchanged)
 151                                *envchanged = 1;
 152                } else if (!strcmp(cmd, "--work-tree")) {
 153                        if (*argc < 2) {
 154                                fprintf(stderr, "No directory given for --work-tree.\n" );
 155                                usage(git_usage_string);
 156                        }
 157                        setenv(GIT_WORK_TREE_ENVIRONMENT, (*argv)[1], 1);
 158                        if (envchanged)
 159                                *envchanged = 1;
 160                        (*argv)++;
 161                        (*argc)--;
 162                } else if (skip_prefix(cmd, "--work-tree=", &cmd)) {
 163                        setenv(GIT_WORK_TREE_ENVIRONMENT, cmd, 1);
 164                        if (envchanged)
 165                                *envchanged = 1;
 166                } else if (!strcmp(cmd, "--bare")) {
 167                        char *cwd = xgetcwd();
 168                        is_bare_repository_cfg = 1;
 169                        setenv(GIT_DIR_ENVIRONMENT, cwd, 0);
 170                        free(cwd);
 171                        setenv(GIT_IMPLICIT_WORK_TREE_ENVIRONMENT, "0", 1);
 172                        if (envchanged)
 173                                *envchanged = 1;
 174                } else if (!strcmp(cmd, "-c")) {
 175                        if (*argc < 2) {
 176                                fprintf(stderr, "-c expects a configuration string\n" );
 177                                usage(git_usage_string);
 178                        }
 179                        git_config_push_parameter((*argv)[1]);
 180                        (*argv)++;
 181                        (*argc)--;
 182                } else if (!strcmp(cmd, "--literal-pathspecs")) {
 183                        setenv(GIT_LITERAL_PATHSPECS_ENVIRONMENT, "1", 1);
 184                        if (envchanged)
 185                                *envchanged = 1;
 186                } else if (!strcmp(cmd, "--no-literal-pathspecs")) {
 187                        setenv(GIT_LITERAL_PATHSPECS_ENVIRONMENT, "0", 1);
 188                        if (envchanged)
 189                                *envchanged = 1;
 190                } else if (!strcmp(cmd, "--glob-pathspecs")) {
 191                        setenv(GIT_GLOB_PATHSPECS_ENVIRONMENT, "1", 1);
 192                        if (envchanged)
 193                                *envchanged = 1;
 194                } else if (!strcmp(cmd, "--noglob-pathspecs")) {
 195                        setenv(GIT_NOGLOB_PATHSPECS_ENVIRONMENT, "1", 1);
 196                        if (envchanged)
 197                                *envchanged = 1;
 198                } else if (!strcmp(cmd, "--icase-pathspecs")) {
 199                        setenv(GIT_ICASE_PATHSPECS_ENVIRONMENT, "1", 1);
 200                        if (envchanged)
 201                                *envchanged = 1;
 202                } else if (!strcmp(cmd, "--shallow-file")) {
 203                        (*argv)++;
 204                        (*argc)--;
 205                        set_alternate_shallow_file((*argv)[0], 1);
 206                        if (envchanged)
 207                                *envchanged = 1;
 208                } else if (!strcmp(cmd, "-C")) {
 209                        if (*argc < 2) {
 210                                fprintf(stderr, "No directory given for -C.\n" );
 211                                usage(git_usage_string);
 212                        }
 213                        if ((*argv)[1][0]) {
 214                                if (chdir((*argv)[1]))
 215                                        die_errno("Cannot change to '%s'", (*argv)[1]);
 216                                if (envchanged)
 217                                        *envchanged = 1;
 218                        }
 219                        (*argv)++;
 220                        (*argc)--;
 221                } else {
 222                        fprintf(stderr, "Unknown option: %s\n", cmd);
 223                        usage(git_usage_string);
 224                }
 225
 226                (*argv)++;
 227                (*argc)--;
 228        }
 229        return (*argv) - orig_argv;
 230}
 231
 232static int handle_alias(int *argcp, const char ***argv)
 233{
 234        int envchanged = 0, ret = 0, saved_errno = errno;
 235        int count, option_count;
 236        const char **new_argv;
 237        const char *alias_command;
 238        char *alias_string;
 239        int unused_nongit;
 240
 241        save_env_before_alias();
 242        setup_git_directory_gently(&unused_nongit);
 243
 244        alias_command = (*argv)[0];
 245        alias_string = alias_lookup(alias_command);
 246        if (alias_string) {
 247                if (alias_string[0] == '!') {
 248                        struct child_process child = CHILD_PROCESS_INIT;
 249
 250                        commit_pager_choice();
 251                        restore_env(1);
 252
 253                        child.use_shell = 1;
 254                        argv_array_push(&child.args, alias_string + 1);
 255                        argv_array_pushv(&child.args, (*argv) + 1);
 256
 257                        ret = run_command(&child);
 258                        if (ret >= 0)   /* normal exit */
 259                                exit(ret);
 260
 261                        die_errno("While expanding alias '%s': '%s'",
 262                            alias_command, alias_string + 1);
 263                }
 264                count = split_cmdline(alias_string, &new_argv);
 265                if (count < 0)
 266                        die("Bad alias.%s string: %s", alias_command,
 267                            split_cmdline_strerror(count));
 268                option_count = handle_options(&new_argv, &count, &envchanged);
 269                if (envchanged)
 270                        die("alias '%s' changes environment variables\n"
 271                                 "You can use '!git' in the alias to do this.",
 272                                 alias_command);
 273                memmove(new_argv - option_count, new_argv,
 274                                count * sizeof(char *));
 275                new_argv -= option_count;
 276
 277                if (count < 1)
 278                        die("empty alias for %s", alias_command);
 279
 280                if (!strcmp(alias_command, new_argv[0]))
 281                        die("recursive alias: %s", alias_command);
 282
 283                trace_argv_printf(new_argv,
 284                                  "trace: alias expansion: %s =>",
 285                                  alias_command);
 286
 287                REALLOC_ARRAY(new_argv, count + *argcp);
 288                /* insert after command name */
 289                memcpy(new_argv + count, *argv + 1, sizeof(char *) * *argcp);
 290
 291                *argv = new_argv;
 292                *argcp += count - 1;
 293
 294                ret = 1;
 295        }
 296
 297        restore_env(0);
 298
 299        errno = saved_errno;
 300
 301        return ret;
 302}
 303
 304#define RUN_SETUP               (1<<0)
 305#define RUN_SETUP_GENTLY        (1<<1)
 306#define USE_PAGER               (1<<2)
 307/*
 308 * require working tree to be present -- anything uses this needs
 309 * RUN_SETUP for reading from the configuration file.
 310 */
 311#define NEED_WORK_TREE          (1<<3)
 312
 313struct cmd_struct {
 314        const char *cmd;
 315        int (*fn)(int, const char **, const char *);
 316        int option;
 317};
 318
 319static int run_builtin(struct cmd_struct *p, int argc, const char **argv)
 320{
 321        int status, help;
 322        struct stat st;
 323        const char *prefix;
 324
 325        prefix = NULL;
 326        help = argc == 2 && !strcmp(argv[1], "-h");
 327        if (!help) {
 328                if (p->option & RUN_SETUP)
 329                        prefix = setup_git_directory();
 330                else if (p->option & RUN_SETUP_GENTLY) {
 331                        int nongit_ok;
 332                        prefix = setup_git_directory_gently(&nongit_ok);
 333                }
 334
 335                if (use_pager == -1 && p->option & (RUN_SETUP | RUN_SETUP_GENTLY))
 336                        use_pager = check_pager_config(p->cmd);
 337                if (use_pager == -1 && p->option & USE_PAGER)
 338                        use_pager = 1;
 339
 340                if ((p->option & (RUN_SETUP | RUN_SETUP_GENTLY)) &&
 341                    startup_info->have_repository) /* get_git_dir() may set up repo, avoid that */
 342                        trace_repo_setup(prefix);
 343        }
 344        commit_pager_choice();
 345
 346        if (!help && p->option & NEED_WORK_TREE)
 347                setup_work_tree();
 348
 349        trace_argv_printf(argv, "trace: built-in: git");
 350
 351        status = p->fn(argc, argv, prefix);
 352        if (status)
 353                return status;
 354
 355        /* Somebody closed stdout? */
 356        if (fstat(fileno(stdout), &st))
 357                return 0;
 358        /* Ignore write errors for pipes and sockets.. */
 359        if (S_ISFIFO(st.st_mode) || S_ISSOCK(st.st_mode))
 360                return 0;
 361
 362        /* Check for ENOSPC and EIO errors.. */
 363        if (fflush(stdout))
 364                die_errno("write failure on standard output");
 365        if (ferror(stdout))
 366                die("unknown write failure on standard output");
 367        if (fclose(stdout))
 368                die_errno("close failed on standard output");
 369        return 0;
 370}
 371
 372static struct cmd_struct commands[] = {
 373        { "add", cmd_add, RUN_SETUP | NEED_WORK_TREE },
 374        { "am", cmd_am, 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_GENTLY },
 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        { "pull", cmd_pull, RUN_SETUP | NEED_WORK_TREE },
 451        { "push", cmd_push, RUN_SETUP },
 452        { "read-tree", cmd_read_tree, RUN_SETUP },
 453        { "receive-pack", cmd_receive_pack },
 454        { "reflog", cmd_reflog, RUN_SETUP },
 455        { "remote", cmd_remote, RUN_SETUP },
 456        { "remote-ext", cmd_remote_ext },
 457        { "remote-fd", cmd_remote_fd },
 458        { "repack", cmd_repack, RUN_SETUP },
 459        { "replace", cmd_replace, RUN_SETUP },
 460        { "rerere", cmd_rerere, RUN_SETUP },
 461        { "reset", cmd_reset, RUN_SETUP },
 462        { "rev-list", cmd_rev_list, RUN_SETUP },
 463        { "rev-parse", cmd_rev_parse },
 464        { "revert", cmd_revert, RUN_SETUP | NEED_WORK_TREE },
 465        { "rm", cmd_rm, RUN_SETUP },
 466        { "send-pack", cmd_send_pack, RUN_SETUP },
 467        { "shortlog", cmd_shortlog, RUN_SETUP_GENTLY | USE_PAGER },
 468        { "show", cmd_show, RUN_SETUP },
 469        { "show-branch", cmd_show_branch, RUN_SETUP },
 470        { "show-ref", cmd_show_ref, RUN_SETUP },
 471        { "stage", cmd_add, RUN_SETUP | NEED_WORK_TREE },
 472        { "status", cmd_status, RUN_SETUP | NEED_WORK_TREE },
 473        { "stripspace", cmd_stripspace },
 474        { "submodule--helper", cmd_submodule__helper, RUN_SETUP },
 475        { "symbolic-ref", cmd_symbolic_ref, RUN_SETUP },
 476        { "tag", cmd_tag, RUN_SETUP },
 477        { "unpack-file", cmd_unpack_file, RUN_SETUP },
 478        { "unpack-objects", cmd_unpack_objects, RUN_SETUP },
 479        { "update-index", cmd_update_index, RUN_SETUP },
 480        { "update-ref", cmd_update_ref, RUN_SETUP },
 481        { "update-server-info", cmd_update_server_info, RUN_SETUP },
 482        { "upload-archive", cmd_upload_archive },
 483        { "upload-archive--writer", cmd_upload_archive_writer },
 484        { "var", cmd_var, RUN_SETUP_GENTLY },
 485        { "verify-commit", cmd_verify_commit, RUN_SETUP },
 486        { "verify-pack", cmd_verify_pack },
 487        { "verify-tag", cmd_verify_tag, RUN_SETUP },
 488        { "version", cmd_version },
 489        { "whatchanged", cmd_whatchanged, RUN_SETUP },
 490        { "worktree", cmd_worktree, RUN_SETUP },
 491        { "write-tree", cmd_write_tree, RUN_SETUP },
 492};
 493
 494static struct cmd_struct *get_builtin(const char *s)
 495{
 496        int i;
 497        for (i = 0; i < ARRAY_SIZE(commands); i++) {
 498                struct cmd_struct *p = commands + i;
 499                if (!strcmp(s, p->cmd))
 500                        return p;
 501        }
 502        return NULL;
 503}
 504
 505int is_builtin(const char *s)
 506{
 507        return !!get_builtin(s);
 508}
 509
 510#ifdef STRIP_EXTENSION
 511static void strip_extension(const char **argv)
 512{
 513        size_t len;
 514
 515        if (strip_suffix(argv[0], STRIP_EXTENSION, &len))
 516                argv[0] = xmemdupz(argv[0], len);
 517}
 518#else
 519#define strip_extension(cmd)
 520#endif
 521
 522static void handle_builtin(int argc, const char **argv)
 523{
 524        const char *cmd;
 525        struct cmd_struct *builtin;
 526
 527        strip_extension(argv);
 528        cmd = argv[0];
 529
 530        /* Turn "git cmd --help" into "git help cmd" */
 531        if (argc > 1 && !strcmp(argv[1], "--help")) {
 532                argv[1] = argv[0];
 533                argv[0] = cmd = "help";
 534        }
 535
 536        builtin = get_builtin(cmd);
 537        if (builtin)
 538                exit(run_builtin(builtin, argc, argv));
 539}
 540
 541static void execv_dashed_external(const char **argv)
 542{
 543        struct strbuf cmd = STRBUF_INIT;
 544        const char *tmp;
 545        int status;
 546
 547        if (use_pager == -1)
 548                use_pager = check_pager_config(argv[0]);
 549        commit_pager_choice();
 550
 551        strbuf_addf(&cmd, "git-%s", argv[0]);
 552
 553        /*
 554         * argv[0] must be the git command, but the argv array
 555         * belongs to the caller, and may be reused in
 556         * subsequent loop iterations. Save argv[0] and
 557         * restore it on error.
 558         */
 559        tmp = argv[0];
 560        argv[0] = cmd.buf;
 561
 562        trace_argv_printf(argv, "trace: exec:");
 563
 564        /*
 565         * if we fail because the command is not found, it is
 566         * OK to return. Otherwise, we just pass along the status code.
 567         */
 568        status = run_command_v_opt(argv, RUN_SILENT_EXEC_FAILURE | RUN_CLEAN_ON_EXIT);
 569        if (status >= 0 || errno != ENOENT)
 570                exit(status);
 571
 572        argv[0] = tmp;
 573
 574        strbuf_release(&cmd);
 575}
 576
 577static int run_argv(int *argcp, const char ***argv)
 578{
 579        int done_alias = 0;
 580
 581        while (1) {
 582                /*
 583                 * If we tried alias and futzed with our environment,
 584                 * it no longer is safe to invoke builtins directly in
 585                 * general.  We have to spawn them as dashed externals.
 586                 *
 587                 * NEEDSWORK: if we can figure out cases
 588                 * where it is safe to do, we can avoid spawning a new
 589                 * process.
 590                 */
 591                if (!done_alias)
 592                        handle_builtin(*argcp, *argv);
 593
 594                /* .. then try the external ones */
 595                execv_dashed_external(*argv);
 596
 597                /* It could be an alias -- this works around the insanity
 598                 * of overriding "git log" with "git show" by having
 599                 * alias.log = show
 600                 */
 601                if (done_alias)
 602                        break;
 603                if (!handle_alias(argcp, argv))
 604                        break;
 605                done_alias = 1;
 606        }
 607
 608        return done_alias;
 609}
 610
 611int cmd_main(int argc, const char **argv)
 612{
 613        const char *cmd;
 614        int done_help = 0;
 615
 616        cmd = argv[0];
 617        if (!cmd)
 618                cmd = "git-help";
 619
 620        trace_command_performance(argv);
 621
 622        /*
 623         * "git-xxxx" is the same as "git xxxx", but we obviously:
 624         *
 625         *  - cannot take flags in between the "git" and the "xxxx".
 626         *  - cannot execute it externally (since it would just do
 627         *    the same thing over again)
 628         *
 629         * So we just directly call the builtin handler, and die if
 630         * that one cannot handle it.
 631         */
 632        if (skip_prefix(cmd, "git-", &cmd)) {
 633                argv[0] = cmd;
 634                handle_builtin(argc, argv);
 635                die("cannot handle %s as a builtin", cmd);
 636        }
 637
 638        /* Look for flags.. */
 639        argv++;
 640        argc--;
 641        handle_options(&argv, &argc, NULL);
 642        if (argc > 0) {
 643                /* translate --help and --version into commands */
 644                skip_prefix(argv[0], "--", &argv[0]);
 645        } else {
 646                /* The user didn't specify a command; give them help */
 647                commit_pager_choice();
 648                printf("usage: %s\n\n", git_usage_string);
 649                list_common_cmds_help();
 650                printf("\n%s\n", _(git_more_info_string));
 651                exit(1);
 652        }
 653        cmd = argv[0];
 654
 655        /*
 656         * We use PATH to find git commands, but we prepend some higher
 657         * precedence paths: the "--exec-path" option, the GIT_EXEC_PATH
 658         * environment, and the $(gitexecdir) from the Makefile at build
 659         * time.
 660         */
 661        setup_path();
 662
 663        while (1) {
 664                int was_alias = run_argv(&argc, &argv);
 665                if (errno != ENOENT)
 666                        break;
 667                if (was_alias) {
 668                        fprintf(stderr, "Expansion of alias '%s' failed; "
 669                                "'%s' is not a git command\n",
 670                                cmd, argv[0]);
 671                        exit(1);
 672                }
 673                if (!done_help) {
 674                        cmd = argv[0] = help_unknown_cmd(cmd);
 675                        done_help = 1;
 676                } else
 677                        break;
 678        }
 679
 680        fprintf(stderr, "Failed to run command '%s': %s\n",
 681                cmd, strerror(errno));
 682
 683        return 1;
 684}