Andrew's git / gitweb.git / git.c
?
git.con commit doc: rewrite description for rev-parse --short (fb87327)
   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, "--super-prefix")) {
 167                        if (*argc < 2) {
 168                                fprintf(stderr, "No prefix given for --super-prefix.\n" );
 169                                usage(git_usage_string);
 170                        }
 171                        setenv(GIT_SUPER_PREFIX_ENVIRONMENT, (*argv)[1], 1);
 172                        if (envchanged)
 173                                *envchanged = 1;
 174                        (*argv)++;
 175                        (*argc)--;
 176                } else if (skip_prefix(cmd, "--super-prefix=", &cmd)) {
 177                        setenv(GIT_SUPER_PREFIX_ENVIRONMENT, cmd, 1);
 178                        if (envchanged)
 179                                *envchanged = 1;
 180                } else if (!strcmp(cmd, "--bare")) {
 181                        char *cwd = xgetcwd();
 182                        is_bare_repository_cfg = 1;
 183                        setenv(GIT_DIR_ENVIRONMENT, cwd, 0);
 184                        free(cwd);
 185                        setenv(GIT_IMPLICIT_WORK_TREE_ENVIRONMENT, "0", 1);
 186                        if (envchanged)
 187                                *envchanged = 1;
 188                } else if (!strcmp(cmd, "-c")) {
 189                        if (*argc < 2) {
 190                                fprintf(stderr, "-c expects a configuration string\n" );
 191                                usage(git_usage_string);
 192                        }
 193                        git_config_push_parameter((*argv)[1]);
 194                        (*argv)++;
 195                        (*argc)--;
 196                } else if (!strcmp(cmd, "--literal-pathspecs")) {
 197                        setenv(GIT_LITERAL_PATHSPECS_ENVIRONMENT, "1", 1);
 198                        if (envchanged)
 199                                *envchanged = 1;
 200                } else if (!strcmp(cmd, "--no-literal-pathspecs")) {
 201                        setenv(GIT_LITERAL_PATHSPECS_ENVIRONMENT, "0", 1);
 202                        if (envchanged)
 203                                *envchanged = 1;
 204                } else if (!strcmp(cmd, "--glob-pathspecs")) {
 205                        setenv(GIT_GLOB_PATHSPECS_ENVIRONMENT, "1", 1);
 206                        if (envchanged)
 207                                *envchanged = 1;
 208                } else if (!strcmp(cmd, "--noglob-pathspecs")) {
 209                        setenv(GIT_NOGLOB_PATHSPECS_ENVIRONMENT, "1", 1);
 210                        if (envchanged)
 211                                *envchanged = 1;
 212                } else if (!strcmp(cmd, "--icase-pathspecs")) {
 213                        setenv(GIT_ICASE_PATHSPECS_ENVIRONMENT, "1", 1);
 214                        if (envchanged)
 215                                *envchanged = 1;
 216                } else if (!strcmp(cmd, "--shallow-file")) {
 217                        (*argv)++;
 218                        (*argc)--;
 219                        set_alternate_shallow_file((*argv)[0], 1);
 220                        if (envchanged)
 221                                *envchanged = 1;
 222                } else if (!strcmp(cmd, "-C")) {
 223                        if (*argc < 2) {
 224                                fprintf(stderr, "No directory given for -C.\n" );
 225                                usage(git_usage_string);
 226                        }
 227                        if ((*argv)[1][0]) {
 228                                if (chdir((*argv)[1]))
 229                                        die_errno("Cannot change to '%s'", (*argv)[1]);
 230                                if (envchanged)
 231                                        *envchanged = 1;
 232                        }
 233                        (*argv)++;
 234                        (*argc)--;
 235                } else {
 236                        fprintf(stderr, "Unknown option: %s\n", cmd);
 237                        usage(git_usage_string);
 238                }
 239
 240                (*argv)++;
 241                (*argc)--;
 242        }
 243        return (*argv) - orig_argv;
 244}
 245
 246static int handle_alias(int *argcp, const char ***argv)
 247{
 248        int envchanged = 0, ret = 0, saved_errno = errno;
 249        int count, option_count;
 250        const char **new_argv;
 251        const char *alias_command;
 252        char *alias_string;
 253        int unused_nongit;
 254
 255        save_env_before_alias();
 256        setup_git_directory_gently(&unused_nongit);
 257
 258        alias_command = (*argv)[0];
 259        alias_string = alias_lookup(alias_command);
 260        if (alias_string) {
 261                if (alias_string[0] == '!') {
 262                        struct child_process child = CHILD_PROCESS_INIT;
 263
 264                        commit_pager_choice();
 265                        restore_env(1);
 266
 267                        child.use_shell = 1;
 268                        argv_array_push(&child.args, alias_string + 1);
 269                        argv_array_pushv(&child.args, (*argv) + 1);
 270
 271                        ret = run_command(&child);
 272                        if (ret >= 0)   /* normal exit */
 273                                exit(ret);
 274
 275                        die_errno("While expanding alias '%s': '%s'",
 276                            alias_command, alias_string + 1);
 277                }
 278                count = split_cmdline(alias_string, &new_argv);
 279                if (count < 0)
 280                        die("Bad alias.%s string: %s", alias_command,
 281                            split_cmdline_strerror(count));
 282                option_count = handle_options(&new_argv, &count, &envchanged);
 283                if (envchanged)
 284                        die("alias '%s' changes environment variables\n"
 285                                 "You can use '!git' in the alias to do this.",
 286                                 alias_command);
 287                memmove(new_argv - option_count, new_argv,
 288                                count * sizeof(char *));
 289                new_argv -= option_count;
 290
 291                if (count < 1)
 292                        die("empty alias for %s", alias_command);
 293
 294                if (!strcmp(alias_command, new_argv[0]))
 295                        die("recursive alias: %s", alias_command);
 296
 297                trace_argv_printf(new_argv,
 298                                  "trace: alias expansion: %s =>",
 299                                  alias_command);
 300
 301                REALLOC_ARRAY(new_argv, count + *argcp);
 302                /* insert after command name */
 303                memcpy(new_argv + count, *argv + 1, sizeof(char *) * *argcp);
 304
 305                *argv = new_argv;
 306                *argcp += count - 1;
 307
 308                ret = 1;
 309        }
 310
 311        restore_env(0);
 312
 313        errno = saved_errno;
 314
 315        return ret;
 316}
 317
 318#define RUN_SETUP               (1<<0)
 319#define RUN_SETUP_GENTLY        (1<<1)
 320#define USE_PAGER               (1<<2)
 321/*
 322 * require working tree to be present -- anything uses this needs
 323 * RUN_SETUP for reading from the configuration file.
 324 */
 325#define NEED_WORK_TREE          (1<<3)
 326#define SUPPORT_SUPER_PREFIX    (1<<4)
 327
 328struct cmd_struct {
 329        const char *cmd;
 330        int (*fn)(int, const char **, const char *);
 331        int option;
 332};
 333
 334static int run_builtin(struct cmd_struct *p, int argc, const char **argv)
 335{
 336        int status, help;
 337        struct stat st;
 338        const char *prefix;
 339
 340        prefix = NULL;
 341        help = argc == 2 && !strcmp(argv[1], "-h");
 342        if (!help) {
 343                if (p->option & RUN_SETUP)
 344                        prefix = setup_git_directory();
 345                else if (p->option & RUN_SETUP_GENTLY) {
 346                        int nongit_ok;
 347                        prefix = setup_git_directory_gently(&nongit_ok);
 348                }
 349
 350                if (use_pager == -1 && p->option & (RUN_SETUP | RUN_SETUP_GENTLY))
 351                        use_pager = check_pager_config(p->cmd);
 352                if (use_pager == -1 && p->option & USE_PAGER)
 353                        use_pager = 1;
 354
 355                if ((p->option & (RUN_SETUP | RUN_SETUP_GENTLY)) &&
 356                    startup_info->have_repository) /* get_git_dir() may set up repo, avoid that */
 357                        trace_repo_setup(prefix);
 358        }
 359        commit_pager_choice();
 360
 361        if (!help && get_super_prefix()) {
 362                if (!(p->option & SUPPORT_SUPER_PREFIX))
 363                        die("%s doesn't support --super-prefix", p->cmd);
 364        }
 365
 366        if (!help && p->option & NEED_WORK_TREE)
 367                setup_work_tree();
 368
 369        trace_argv_printf(argv, "trace: built-in: git");
 370
 371        status = p->fn(argc, argv, prefix);
 372        if (status)
 373                return status;
 374
 375        /* Somebody closed stdout? */
 376        if (fstat(fileno(stdout), &st))
 377                return 0;
 378        /* Ignore write errors for pipes and sockets.. */
 379        if (S_ISFIFO(st.st_mode) || S_ISSOCK(st.st_mode))
 380                return 0;
 381
 382        /* Check for ENOSPC and EIO errors.. */
 383        if (fflush(stdout))
 384                die_errno("write failure on standard output");
 385        if (ferror(stdout))
 386                die("unknown write failure on standard output");
 387        if (fclose(stdout))
 388                die_errno("close failed on standard output");
 389        return 0;
 390}
 391
 392static struct cmd_struct commands[] = {
 393        { "add", cmd_add, RUN_SETUP | NEED_WORK_TREE },
 394        { "am", cmd_am, RUN_SETUP | NEED_WORK_TREE },
 395        { "annotate", cmd_annotate, RUN_SETUP },
 396        { "apply", cmd_apply, RUN_SETUP_GENTLY },
 397        { "archive", cmd_archive, RUN_SETUP_GENTLY },
 398        { "bisect--helper", cmd_bisect__helper, RUN_SETUP },
 399        { "blame", cmd_blame, RUN_SETUP },
 400        { "branch", cmd_branch, RUN_SETUP },
 401        { "bundle", cmd_bundle, RUN_SETUP_GENTLY },
 402        { "cat-file", cmd_cat_file, RUN_SETUP },
 403        { "check-attr", cmd_check_attr, RUN_SETUP },
 404        { "check-ignore", cmd_check_ignore, RUN_SETUP | NEED_WORK_TREE },
 405        { "check-mailmap", cmd_check_mailmap, RUN_SETUP },
 406        { "check-ref-format", cmd_check_ref_format },
 407        { "checkout", cmd_checkout, RUN_SETUP | NEED_WORK_TREE },
 408        { "checkout-index", cmd_checkout_index,
 409                RUN_SETUP | NEED_WORK_TREE},
 410        { "cherry", cmd_cherry, RUN_SETUP },
 411        { "cherry-pick", cmd_cherry_pick, RUN_SETUP | NEED_WORK_TREE },
 412        { "clean", cmd_clean, RUN_SETUP | NEED_WORK_TREE },
 413        { "clone", cmd_clone },
 414        { "column", cmd_column, RUN_SETUP_GENTLY },
 415        { "commit", cmd_commit, RUN_SETUP | NEED_WORK_TREE },
 416        { "commit-tree", cmd_commit_tree, RUN_SETUP },
 417        { "config", cmd_config, RUN_SETUP_GENTLY },
 418        { "count-objects", cmd_count_objects, RUN_SETUP },
 419        { "credential", cmd_credential, RUN_SETUP_GENTLY },
 420        { "describe", cmd_describe, RUN_SETUP },
 421        { "diff", cmd_diff },
 422        { "diff-files", cmd_diff_files, RUN_SETUP | NEED_WORK_TREE },
 423        { "diff-index", cmd_diff_index, RUN_SETUP },
 424        { "diff-tree", cmd_diff_tree, RUN_SETUP },
 425        { "difftool", cmd_difftool, RUN_SETUP | NEED_WORK_TREE },
 426        { "fast-export", cmd_fast_export, RUN_SETUP },
 427        { "fetch", cmd_fetch, RUN_SETUP },
 428        { "fetch-pack", cmd_fetch_pack, RUN_SETUP },
 429        { "fmt-merge-msg", cmd_fmt_merge_msg, RUN_SETUP },
 430        { "for-each-ref", cmd_for_each_ref, RUN_SETUP },
 431        { "format-patch", cmd_format_patch, RUN_SETUP },
 432        { "fsck", cmd_fsck, RUN_SETUP },
 433        { "fsck-objects", cmd_fsck, RUN_SETUP },
 434        { "gc", cmd_gc, RUN_SETUP },
 435        { "get-tar-commit-id", cmd_get_tar_commit_id },
 436        { "grep", cmd_grep, RUN_SETUP_GENTLY | SUPPORT_SUPER_PREFIX },
 437        { "hash-object", cmd_hash_object },
 438        { "help", cmd_help },
 439        { "index-pack", cmd_index_pack, RUN_SETUP_GENTLY },
 440        { "init", cmd_init_db },
 441        { "init-db", cmd_init_db },
 442        { "interpret-trailers", cmd_interpret_trailers, RUN_SETUP_GENTLY },
 443        { "log", cmd_log, RUN_SETUP },
 444        { "ls-files", cmd_ls_files, RUN_SETUP | SUPPORT_SUPER_PREFIX },
 445        { "ls-remote", cmd_ls_remote, RUN_SETUP_GENTLY },
 446        { "ls-tree", cmd_ls_tree, RUN_SETUP },
 447        { "mailinfo", cmd_mailinfo, RUN_SETUP_GENTLY },
 448        { "mailsplit", cmd_mailsplit },
 449        { "merge", cmd_merge, RUN_SETUP | NEED_WORK_TREE },
 450        { "merge-base", cmd_merge_base, RUN_SETUP },
 451        { "merge-file", cmd_merge_file, RUN_SETUP_GENTLY },
 452        { "merge-index", cmd_merge_index, RUN_SETUP },
 453        { "merge-ours", cmd_merge_ours, RUN_SETUP },
 454        { "merge-recursive", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE },
 455        { "merge-recursive-ours", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE },
 456        { "merge-recursive-theirs", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE },
 457        { "merge-subtree", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE },
 458        { "merge-tree", cmd_merge_tree, RUN_SETUP },
 459        { "mktag", cmd_mktag, RUN_SETUP },
 460        { "mktree", cmd_mktree, RUN_SETUP },
 461        { "mv", cmd_mv, RUN_SETUP | NEED_WORK_TREE },
 462        { "name-rev", cmd_name_rev, RUN_SETUP },
 463        { "notes", cmd_notes, RUN_SETUP },
 464        { "pack-objects", cmd_pack_objects, RUN_SETUP },
 465        { "pack-redundant", cmd_pack_redundant, RUN_SETUP },
 466        { "pack-refs", cmd_pack_refs, RUN_SETUP },
 467        { "patch-id", cmd_patch_id, RUN_SETUP_GENTLY },
 468        { "pickaxe", cmd_blame, RUN_SETUP },
 469        { "prune", cmd_prune, RUN_SETUP },
 470        { "prune-packed", cmd_prune_packed, RUN_SETUP },
 471        { "pull", cmd_pull, RUN_SETUP | NEED_WORK_TREE },
 472        { "push", cmd_push, RUN_SETUP },
 473        { "read-tree", cmd_read_tree, RUN_SETUP | SUPPORT_SUPER_PREFIX},
 474        { "rebase--helper", cmd_rebase__helper, RUN_SETUP | NEED_WORK_TREE },
 475        { "receive-pack", cmd_receive_pack },
 476        { "reflog", cmd_reflog, RUN_SETUP },
 477        { "remote", cmd_remote, RUN_SETUP },
 478        { "remote-ext", cmd_remote_ext },
 479        { "remote-fd", cmd_remote_fd },
 480        { "repack", cmd_repack, RUN_SETUP },
 481        { "replace", cmd_replace, RUN_SETUP },
 482        { "rerere", cmd_rerere, RUN_SETUP },
 483        { "reset", cmd_reset, RUN_SETUP },
 484        { "rev-list", cmd_rev_list, RUN_SETUP },
 485        { "rev-parse", cmd_rev_parse },
 486        { "revert", cmd_revert, RUN_SETUP | NEED_WORK_TREE },
 487        { "rm", cmd_rm, RUN_SETUP },
 488        { "send-pack", cmd_send_pack, RUN_SETUP },
 489        { "shortlog", cmd_shortlog, RUN_SETUP_GENTLY | USE_PAGER },
 490        { "show", cmd_show, RUN_SETUP },
 491        { "show-branch", cmd_show_branch, RUN_SETUP },
 492        { "show-ref", cmd_show_ref, RUN_SETUP },
 493        { "stage", cmd_add, RUN_SETUP | NEED_WORK_TREE },
 494        { "status", cmd_status, RUN_SETUP | NEED_WORK_TREE },
 495        { "stripspace", cmd_stripspace },
 496        { "submodule--helper", cmd_submodule__helper, RUN_SETUP | SUPPORT_SUPER_PREFIX},
 497        { "symbolic-ref", cmd_symbolic_ref, RUN_SETUP },
 498        { "tag", cmd_tag, RUN_SETUP },
 499        { "unpack-file", cmd_unpack_file, RUN_SETUP },
 500        { "unpack-objects", cmd_unpack_objects, RUN_SETUP },
 501        { "update-index", cmd_update_index, RUN_SETUP },
 502        { "update-ref", cmd_update_ref, RUN_SETUP },
 503        { "update-server-info", cmd_update_server_info, RUN_SETUP },
 504        { "upload-archive", cmd_upload_archive },
 505        { "upload-archive--writer", cmd_upload_archive_writer },
 506        { "var", cmd_var, RUN_SETUP_GENTLY },
 507        { "verify-commit", cmd_verify_commit, RUN_SETUP },
 508        { "verify-pack", cmd_verify_pack },
 509        { "verify-tag", cmd_verify_tag, RUN_SETUP },
 510        { "version", cmd_version },
 511        { "whatchanged", cmd_whatchanged, RUN_SETUP },
 512        { "worktree", cmd_worktree, RUN_SETUP },
 513        { "write-tree", cmd_write_tree, RUN_SETUP },
 514};
 515
 516static struct cmd_struct *get_builtin(const char *s)
 517{
 518        int i;
 519        for (i = 0; i < ARRAY_SIZE(commands); i++) {
 520                struct cmd_struct *p = commands + i;
 521                if (!strcmp(s, p->cmd))
 522                        return p;
 523        }
 524        return NULL;
 525}
 526
 527int is_builtin(const char *s)
 528{
 529        return !!get_builtin(s);
 530}
 531
 532#ifdef STRIP_EXTENSION
 533static void strip_extension(const char **argv)
 534{
 535        size_t len;
 536
 537        if (strip_suffix(argv[0], STRIP_EXTENSION, &len))
 538                argv[0] = xmemdupz(argv[0], len);
 539}
 540#else
 541#define strip_extension(cmd)
 542#endif
 543
 544static void handle_builtin(int argc, const char **argv)
 545{
 546        struct argv_array args = ARGV_ARRAY_INIT;
 547        const char *cmd;
 548        struct cmd_struct *builtin;
 549
 550        strip_extension(argv);
 551        cmd = argv[0];
 552
 553        /* Turn "git cmd --help" into "git help --exclude-guides cmd" */
 554        if (argc > 1 && !strcmp(argv[1], "--help")) {
 555                int i;
 556
 557                argv[1] = argv[0];
 558                argv[0] = cmd = "help";
 559
 560                for (i = 0; i < argc; i++) {
 561                        argv_array_push(&args, argv[i]);
 562                        if (!i)
 563                                argv_array_push(&args, "--exclude-guides");
 564                }
 565
 566                argc++;
 567                argv = args.argv;
 568        }
 569
 570        builtin = get_builtin(cmd);
 571        if (builtin)
 572                exit(run_builtin(builtin, argc, argv));
 573        argv_array_clear(&args);
 574}
 575
 576static void execv_dashed_external(const char **argv)
 577{
 578        struct child_process cmd = CHILD_PROCESS_INIT;
 579        int status;
 580
 581        if (get_super_prefix())
 582                die("%s doesn't support --super-prefix", argv[0]);
 583
 584        if (use_pager == -1)
 585                use_pager = check_pager_config(argv[0]);
 586        commit_pager_choice();
 587
 588        argv_array_pushf(&cmd.args, "git-%s", argv[0]);
 589        argv_array_pushv(&cmd.args, argv + 1);
 590        cmd.clean_on_exit = 1;
 591        cmd.wait_after_clean = 1;
 592        cmd.silent_exec_failure = 1;
 593
 594        trace_argv_printf(cmd.args.argv, "trace: exec:");
 595
 596        /*
 597         * If we fail because the command is not found, it is
 598         * OK to return. Otherwise, we just pass along the status code,
 599         * or our usual generic code if we were not even able to exec
 600         * the program.
 601         */
 602        status = run_command(&cmd);
 603        if (status >= 0)
 604                exit(status);
 605        else if (errno != ENOENT)
 606                exit(128);
 607}
 608
 609static int run_argv(int *argcp, const char ***argv)
 610{
 611        int done_alias = 0;
 612
 613        while (1) {
 614                /*
 615                 * If we tried alias and futzed with our environment,
 616                 * it no longer is safe to invoke builtins directly in
 617                 * general.  We have to spawn them as dashed externals.
 618                 *
 619                 * NEEDSWORK: if we can figure out cases
 620                 * where it is safe to do, we can avoid spawning a new
 621                 * process.
 622                 */
 623                if (!done_alias)
 624                        handle_builtin(*argcp, *argv);
 625
 626                /* .. then try the external ones */
 627                execv_dashed_external(*argv);
 628
 629                /* It could be an alias -- this works around the insanity
 630                 * of overriding "git log" with "git show" by having
 631                 * alias.log = show
 632                 */
 633                if (done_alias)
 634                        break;
 635                if (!handle_alias(argcp, argv))
 636                        break;
 637                done_alias = 1;
 638        }
 639
 640        return done_alias;
 641}
 642
 643int cmd_main(int argc, const char **argv)
 644{
 645        const char *cmd;
 646        int done_help = 0;
 647
 648        cmd = argv[0];
 649        if (!cmd)
 650                cmd = "git-help";
 651        else {
 652                const char *slash = find_last_dir_sep(cmd);
 653                if (slash)
 654                        cmd = slash + 1;
 655        }
 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}