git.con commit Git 2.1.2 (80b616d)
   1#include "builtin.h"
   2#include "cache.h"
   3#include "exec_cmd.h"
   4#include "help.h"
   5#include "quote.h"
   6#include "run-command.h"
   7#include "commit.h"
   8
   9const char git_usage_string[] =
  10        "git [--version] [--help] [-C <path>] [-c name=value]\n"
  11        "           [--exec-path[=<path>]] [--html-path] [--man-path] [--info-path]\n"
  12        "           [-p|--paginate|--no-pager] [--no-replace-objects] [--bare]\n"
  13        "           [--git-dir=<path>] [--work-tree=<path>] [--namespace=<name>]\n"
  14        "           <command> [<args>]";
  15
  16const char git_more_info_string[] =
  17        N_("'git help -a' and 'git help -g' lists available subcommands and some\n"
  18           "concept guides. See 'git help <command>' or 'git help <concept>'\n"
  19           "to read about a specific subcommand or concept.");
  20
  21static struct startup_info git_startup_info;
  22static int use_pager = -1;
  23static char orig_cwd[PATH_MAX];
  24static const char *env_names[] = {
  25        GIT_DIR_ENVIRONMENT,
  26        GIT_WORK_TREE_ENVIRONMENT,
  27        GIT_IMPLICIT_WORK_TREE_ENVIRONMENT,
  28        GIT_PREFIX_ENVIRONMENT
  29};
  30static char *orig_env[4];
  31static int saved_environment;
  32
  33static void save_env(void)
  34{
  35        int i;
  36        if (saved_environment)
  37                return;
  38        saved_environment = 1;
  39        if (!getcwd(orig_cwd, sizeof(orig_cwd)))
  40                die_errno("cannot getcwd");
  41        for (i = 0; i < ARRAY_SIZE(env_names); i++) {
  42                orig_env[i] = getenv(env_names[i]);
  43                if (orig_env[i])
  44                        orig_env[i] = xstrdup(orig_env[i]);
  45        }
  46}
  47
  48static void restore_env(void)
  49{
  50        int i;
  51        if (*orig_cwd && chdir(orig_cwd))
  52                die_errno("could not move to %s", orig_cwd);
  53        for (i = 0; i < ARRAY_SIZE(env_names); i++) {
  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                        static char git_dir[PATH_MAX+1];
 165                        is_bare_repository_cfg = 1;
 166                        setenv(GIT_DIR_ENVIRONMENT, getcwd(git_dir, sizeof(git_dir)), 0);
 167                        setenv(GIT_IMPLICIT_WORK_TREE_ENVIRONMENT, "0", 1);
 168                        if (envchanged)
 169                                *envchanged = 1;
 170                } else if (!strcmp(cmd, "-c")) {
 171                        if (*argc < 2) {
 172                                fprintf(stderr, "-c expects a configuration string\n" );
 173                                usage(git_usage_string);
 174                        }
 175                        git_config_push_parameter((*argv)[1]);
 176                        (*argv)++;
 177                        (*argc)--;
 178                } else if (!strcmp(cmd, "--literal-pathspecs")) {
 179                        setenv(GIT_LITERAL_PATHSPECS_ENVIRONMENT, "1", 1);
 180                        if (envchanged)
 181                                *envchanged = 1;
 182                } else if (!strcmp(cmd, "--no-literal-pathspecs")) {
 183                        setenv(GIT_LITERAL_PATHSPECS_ENVIRONMENT, "0", 1);
 184                        if (envchanged)
 185                                *envchanged = 1;
 186                } else if (!strcmp(cmd, "--glob-pathspecs")) {
 187                        setenv(GIT_GLOB_PATHSPECS_ENVIRONMENT, "1", 1);
 188                        if (envchanged)
 189                                *envchanged = 1;
 190                } else if (!strcmp(cmd, "--noglob-pathspecs")) {
 191                        setenv(GIT_NOGLOB_PATHSPECS_ENVIRONMENT, "1", 1);
 192                        if (envchanged)
 193                                *envchanged = 1;
 194                } else if (!strcmp(cmd, "--icase-pathspecs")) {
 195                        setenv(GIT_ICASE_PATHSPECS_ENVIRONMENT, "1", 1);
 196                        if (envchanged)
 197                                *envchanged = 1;
 198                } else if (!strcmp(cmd, "--shallow-file")) {
 199                        (*argv)++;
 200                        (*argc)--;
 201                        set_alternate_shallow_file((*argv)[0], 1);
 202                        if (envchanged)
 203                                *envchanged = 1;
 204                } else if (!strcmp(cmd, "-C")) {
 205                        if (*argc < 2) {
 206                                fprintf(stderr, "No directory given for -C.\n" );
 207                                usage(git_usage_string);
 208                        }
 209                        if (chdir((*argv)[1]))
 210                                die_errno("Cannot change to '%s'", (*argv)[1]);
 211                        if (envchanged)
 212                                *envchanged = 1;
 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                new_argv = xrealloc(new_argv, sizeof(char *) *
 285                                    (count + *argcp));
 286                /* insert after command name */
 287                memcpy(new_argv + count, *argv + 1, sizeof(char *) * *argcp);
 288
 289                *argv = new_argv;
 290                *argcp += count - 1;
 291
 292                ret = 1;
 293        }
 294
 295        if (subdir && chdir(subdir))
 296                die_errno("Cannot change to '%s'", subdir);
 297
 298        errno = saved_errno;
 299
 300        return ret;
 301}
 302
 303#define RUN_SETUP               (1<<0)
 304#define RUN_SETUP_GENTLY        (1<<1)
 305#define USE_PAGER               (1<<2)
 306/*
 307 * require working tree to be present -- anything uses this needs
 308 * RUN_SETUP for reading from the configuration file.
 309 */
 310#define NEED_WORK_TREE          (1<<3)
 311#define NO_SETUP                (1<<4)
 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        { "annotate", cmd_annotate, RUN_SETUP },
 375        { "apply", cmd_apply, RUN_SETUP_GENTLY },
 376        { "archive", cmd_archive },
 377        { "bisect--helper", cmd_bisect__helper, RUN_SETUP },
 378        { "blame", cmd_blame, RUN_SETUP },
 379        { "branch", cmd_branch, RUN_SETUP },
 380        { "bundle", cmd_bundle, RUN_SETUP_GENTLY },
 381        { "cat-file", cmd_cat_file, RUN_SETUP },
 382        { "check-attr", cmd_check_attr, RUN_SETUP },
 383        { "check-ignore", cmd_check_ignore, RUN_SETUP | NEED_WORK_TREE },
 384        { "check-mailmap", cmd_check_mailmap, RUN_SETUP },
 385        { "check-ref-format", cmd_check_ref_format },
 386        { "checkout", cmd_checkout, RUN_SETUP | NEED_WORK_TREE },
 387        { "checkout-index", cmd_checkout_index,
 388                RUN_SETUP | NEED_WORK_TREE},
 389        { "cherry", cmd_cherry, RUN_SETUP },
 390        { "cherry-pick", cmd_cherry_pick, RUN_SETUP | NEED_WORK_TREE },
 391        { "clean", cmd_clean, RUN_SETUP | NEED_WORK_TREE },
 392        { "clone", cmd_clone, NO_SETUP },
 393        { "column", cmd_column, RUN_SETUP_GENTLY },
 394        { "commit", cmd_commit, RUN_SETUP | NEED_WORK_TREE },
 395        { "commit-tree", cmd_commit_tree, RUN_SETUP },
 396        { "config", cmd_config, RUN_SETUP_GENTLY },
 397        { "count-objects", cmd_count_objects, RUN_SETUP },
 398        { "credential", cmd_credential, RUN_SETUP_GENTLY },
 399        { "describe", cmd_describe, RUN_SETUP },
 400        { "diff", cmd_diff },
 401        { "diff-files", cmd_diff_files, RUN_SETUP | NEED_WORK_TREE },
 402        { "diff-index", cmd_diff_index, RUN_SETUP },
 403        { "diff-tree", cmd_diff_tree, RUN_SETUP },
 404        { "fast-export", cmd_fast_export, RUN_SETUP },
 405        { "fetch", cmd_fetch, RUN_SETUP },
 406        { "fetch-pack", cmd_fetch_pack, RUN_SETUP },
 407        { "fmt-merge-msg", cmd_fmt_merge_msg, RUN_SETUP },
 408        { "for-each-ref", cmd_for_each_ref, RUN_SETUP },
 409        { "format-patch", cmd_format_patch, RUN_SETUP },
 410        { "fsck", cmd_fsck, RUN_SETUP },
 411        { "fsck-objects", cmd_fsck, RUN_SETUP },
 412        { "gc", cmd_gc, RUN_SETUP },
 413        { "get-tar-commit-id", cmd_get_tar_commit_id },
 414        { "grep", cmd_grep, RUN_SETUP_GENTLY },
 415        { "hash-object", cmd_hash_object },
 416        { "help", cmd_help },
 417        { "index-pack", cmd_index_pack, RUN_SETUP_GENTLY },
 418        { "init", cmd_init_db, NO_SETUP },
 419        { "init-db", cmd_init_db, NO_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
 489int is_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 1;
 496        }
 497        return 0;
 498}
 499
 500static void handle_builtin(int argc, const char **argv)
 501{
 502        const char *cmd = argv[0];
 503        int i;
 504        static const char ext[] = STRIP_EXTENSION;
 505
 506        if (sizeof(ext) > 1) {
 507                i = strlen(argv[0]) - strlen(ext);
 508                if (i > 0 && !strcmp(argv[0] + i, ext)) {
 509                        char *argv0 = xstrdup(argv[0]);
 510                        argv[0] = cmd = argv0;
 511                        argv0[i] = '\0';
 512                }
 513        }
 514
 515        /* Turn "git cmd --help" into "git help cmd" */
 516        if (argc > 1 && !strcmp(argv[1], "--help")) {
 517                argv[1] = argv[0];
 518                argv[0] = cmd = "help";
 519        }
 520
 521        for (i = 0; i < ARRAY_SIZE(commands); i++) {
 522                struct cmd_struct *p = commands+i;
 523                if (strcmp(p->cmd, cmd))
 524                        continue;
 525                if (saved_environment && (p->option & NO_SETUP)) {
 526                        restore_env();
 527                        break;
 528                }
 529                exit(run_builtin(p, argc, argv));
 530        }
 531}
 532
 533static void execv_dashed_external(const char **argv)
 534{
 535        struct strbuf cmd = STRBUF_INIT;
 536        const char *tmp;
 537        int status;
 538
 539        if (use_pager == -1)
 540                use_pager = check_pager_config(argv[0]);
 541        commit_pager_choice();
 542
 543        strbuf_addf(&cmd, "git-%s", argv[0]);
 544
 545        /*
 546         * argv[0] must be the git command, but the argv array
 547         * belongs to the caller, and may be reused in
 548         * subsequent loop iterations. Save argv[0] and
 549         * restore it on error.
 550         */
 551        tmp = argv[0];
 552        argv[0] = cmd.buf;
 553
 554        trace_argv_printf(argv, "trace: exec:");
 555
 556        /*
 557         * if we fail because the command is not found, it is
 558         * OK to return. Otherwise, we just pass along the status code.
 559         */
 560        status = run_command_v_opt(argv, RUN_SILENT_EXEC_FAILURE | RUN_CLEAN_ON_EXIT);
 561        if (status >= 0 || errno != ENOENT)
 562                exit(status);
 563
 564        argv[0] = tmp;
 565
 566        strbuf_release(&cmd);
 567}
 568
 569static int run_argv(int *argcp, const char ***argv)
 570{
 571        int done_alias = 0;
 572
 573        while (1) {
 574                /* See if it's a builtin */
 575                handle_builtin(*argcp, *argv);
 576
 577                /* .. then try the external ones */
 578                execv_dashed_external(*argv);
 579
 580                /* It could be an alias -- this works around the insanity
 581                 * of overriding "git log" with "git show" by having
 582                 * alias.log = show
 583                 */
 584                if (done_alias)
 585                        break;
 586                save_env();
 587                if (!handle_alias(argcp, argv))
 588                        break;
 589                done_alias = 1;
 590        }
 591
 592        return done_alias;
 593}
 594
 595
 596int main(int argc, char **av)
 597{
 598        const char **argv = (const char **) av;
 599        const char *cmd;
 600
 601        startup_info = &git_startup_info;
 602
 603        cmd = git_extract_argv0_path(argv[0]);
 604        if (!cmd)
 605                cmd = "git-help";
 606
 607        /*
 608         * Always open file descriptors 0/1/2 to avoid clobbering files
 609         * in die().  It also avoids messing up when the pipes are dup'ed
 610         * onto stdin/stdout/stderr in the child processes we spawn.
 611         */
 612        sanitize_stdfds();
 613
 614        git_setup_gettext();
 615
 616        trace_command_performance(argv);
 617
 618        /*
 619         * "git-xxxx" is the same as "git xxxx", but we obviously:
 620         *
 621         *  - cannot take flags in between the "git" and the "xxxx".
 622         *  - cannot execute it externally (since it would just do
 623         *    the same thing over again)
 624         *
 625         * So we just directly call the builtin handler, and die if
 626         * that one cannot handle it.
 627         */
 628        if (skip_prefix(cmd, "git-", &cmd)) {
 629                argv[0] = cmd;
 630                handle_builtin(argc, argv);
 631                die("cannot handle %s as a builtin", cmd);
 632        }
 633
 634        /* Look for flags.. */
 635        argv++;
 636        argc--;
 637        handle_options(&argv, &argc, NULL);
 638        if (argc > 0) {
 639                /* translate --help and --version into commands */
 640                skip_prefix(argv[0], "--", &argv[0]);
 641        } else {
 642                /* The user didn't specify a command; give them help */
 643                commit_pager_choice();
 644                printf("usage: %s\n\n", git_usage_string);
 645                list_common_cmds_help();
 646                printf("\n%s\n", _(git_more_info_string));
 647                exit(1);
 648        }
 649        cmd = argv[0];
 650
 651        /*
 652         * We use PATH to find git commands, but we prepend some higher
 653         * precedence paths: the "--exec-path" option, the GIT_EXEC_PATH
 654         * environment, and the $(gitexecdir) from the Makefile at build
 655         * time.
 656         */
 657        setup_path();
 658
 659        while (1) {
 660                static int done_help = 0;
 661                static int was_alias = 0;
 662                was_alias = run_argv(&argc, &argv);
 663                if (errno != ENOENT)
 664                        break;
 665                if (was_alias) {
 666                        fprintf(stderr, "Expansion of alias '%s' failed; "
 667                                "'%s' is not a git command\n",
 668                                cmd, argv[0]);
 669                        exit(1);
 670                }
 671                if (!done_help) {
 672                        cmd = argv[0] = help_unknown_cmd(cmd);
 673                        done_help = 1;
 674                } else
 675                        break;
 676        }
 677
 678        fprintf(stderr, "Failed to run command '%s': %s\n",
 679                cmd, strerror(errno));
 680
 681        return 1;
 682}