git.c

   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
   9 const char git_usage_string[] =
  10         "git [--version] [--help] [-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
  16 const 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
  21 static struct startup_info git_startup_info;
  22 static int use_pager = -1;
  23
  24 static void commit_pager_choice(void) {
  25         switch (use_pager) {
  26         case 0:
  27                 setenv("GIT_PAGER", "cat", 1);
  28                 break;
  29         case 1:
  30                 setup_pager();
  31                 break;
  32         default:
  33                 break;
  34         }
  35 }
  36
  37 static int handle_options(const char ***argv, int *argc, int *envchanged)
  38 {
  39         const char **orig_argv = *argv;
  40
  41         while (*argc > 0) {
  42                 const char *cmd = (*argv)[0];
  43                 if (cmd[0] != '-')
  44                         break;
  45
  46                 /*
  47                  * For legacy reasons, the "version" and "help"
  48                  * commands can be written with "--" prepended
  49                  * to make them look like flags.
  50                  */
  51                 if (!strcmp(cmd, "--help") || !strcmp(cmd, "--version"))
  52                         break;
  53
  54                 /*
  55                  * Check remaining flags.
  56                  */
  57                 if (!prefixcmp(cmd, "--exec-path")) {
  58                         cmd += 11;
  59                         if (*cmd == '=')
  60                                 git_set_argv_exec_path(cmd + 1);
  61                         else {
  62                                 puts(git_exec_path());
  63                                 exit(0);
  64                         }
  65                 } else if (!strcmp(cmd, "--html-path")) {
  66                         puts(system_path(GIT_HTML_PATH));
  67                         exit(0);
  68                 } else if (!strcmp(cmd, "--man-path")) {
  69                         puts(system_path(GIT_MAN_PATH));
  70                         exit(0);
  71                 } else if (!strcmp(cmd, "--info-path")) {
  72                         puts(system_path(GIT_INFO_PATH));
  73                         exit(0);
  74                 } else if (!strcmp(cmd, "-p") || !strcmp(cmd, "--paginate")) {
  75                         use_pager = 1;
  76                 } else if (!strcmp(cmd, "--no-pager")) {
  77                         use_pager = 0;
  78                         if (envchanged)
  79                                 *envchanged = 1;
  80                 } else if (!strcmp(cmd, "--no-replace-objects")) {
  81                         read_replace_refs = 0;
  82                         setenv(NO_REPLACE_OBJECTS_ENVIRONMENT, "1", 1);
  83                         if (envchanged)
  84                                 *envchanged = 1;
  85                 } else if (!strcmp(cmd, "--git-dir")) {
  86                         if (*argc < 2) {
  87                                 fprintf(stderr, "No directory given for --git-dir.\n" );
  88                                 usage(git_usage_string);
  89                         }
  90                         setenv(GIT_DIR_ENVIRONMENT, (*argv)[1], 1);
  91                         if (envchanged)
  92                                 *envchanged = 1;
  93                         (*argv)++;
  94                         (*argc)--;
  95                 } else if (!prefixcmp(cmd, "--git-dir=")) {
  96                         setenv(GIT_DIR_ENVIRONMENT, cmd + 10, 1);
  97                         if (envchanged)
  98                                 *envchanged = 1;
  99                 } else if (!strcmp(cmd, "--namespace")) {
 100                         if (*argc < 2) {
 101                                 fprintf(stderr, "No namespace given for --namespace.\n" );
 102                                 usage(git_usage_string);
 103                         }
 104                         setenv(GIT_NAMESPACE_ENVIRONMENT, (*argv)[1], 1);
 105                         if (envchanged)
 106                                 *envchanged = 1;
 107                         (*argv)++;
 108                         (*argc)--;
 109                 } else if (!prefixcmp(cmd, "--namespace=")) {
 110                         setenv(GIT_NAMESPACE_ENVIRONMENT, cmd + 12, 1);
 111                         if (envchanged)
 112                                 *envchanged = 1;
 113                 } else if (!strcmp(cmd, "--work-tree")) {
 114                         if (*argc < 2) {
 115                                 fprintf(stderr, "No directory given for --work-tree.\n" );
 116                                 usage(git_usage_string);
 117                         }
 118                         setenv(GIT_WORK_TREE_ENVIRONMENT, (*argv)[1], 1);
 119                         if (envchanged)
 120                                 *envchanged = 1;
 121                         (*argv)++;
 122                         (*argc)--;
 123                 } else if (!prefixcmp(cmd, "--work-tree=")) {
 124                         setenv(GIT_WORK_TREE_ENVIRONMENT, cmd + 12, 1);
 125                         if (envchanged)
 126                                 *envchanged = 1;
 127                 } else if (!strcmp(cmd, "--bare")) {
 128                         static char git_dir[PATH_MAX+1];
 129                         is_bare_repository_cfg = 1;
 130                         setenv(GIT_DIR_ENVIRONMENT, getcwd(git_dir, sizeof(git_dir)), 0);
 131                         setenv(GIT_IMPLICIT_WORK_TREE_ENVIRONMENT, "0", 1);
 132                         if (envchanged)
 133                                 *envchanged = 1;
 134                 } else if (!strcmp(cmd, "-c")) {
 135                         if (*argc < 2) {
 136                                 fprintf(stderr, "-c expects a configuration string\n" );
 137                                 usage(git_usage_string);
 138                         }
 139                         git_config_push_parameter((*argv)[1]);
 140                         (*argv)++;
 141                         (*argc)--;
 142                 } else if (!strcmp(cmd, "--literal-pathspecs")) {
 143                         setenv(GIT_LITERAL_PATHSPECS_ENVIRONMENT, "1", 1);
 144                         if (envchanged)
 145                                 *envchanged = 1;
 146                 } else if (!strcmp(cmd, "--no-literal-pathspecs")) {
 147                         setenv(GIT_LITERAL_PATHSPECS_ENVIRONMENT, "0", 1);
 148                         if (envchanged)
 149                                 *envchanged = 1;
 150                 } else if (!strcmp(cmd, "--glob-pathspecs")) {
 151                         setenv(GIT_GLOB_PATHSPECS_ENVIRONMENT, "1", 1);
 152                         if (envchanged)
 153                                 *envchanged = 1;
 154                 } else if (!strcmp(cmd, "--noglob-pathspecs")) {
 155                         setenv(GIT_NOGLOB_PATHSPECS_ENVIRONMENT, "1", 1);
 156                         if (envchanged)
 157                                 *envchanged = 1;
 158                 } else if (!strcmp(cmd, "--icase-pathspecs")) {
 159                         setenv(GIT_ICASE_PATHSPECS_ENVIRONMENT, "1", 1);
 160                         if (envchanged)
 161                                 *envchanged = 1;
 162                 } else if (!strcmp(cmd, "--shallow-file")) {
 163                         (*argv)++;
 164                         (*argc)--;
 165                         set_alternate_shallow_file((*argv)[0]);
 166                         if (envchanged)
 167                                 *envchanged = 1;
 168                 } else {
 169                         fprintf(stderr, "Unknown option: %s\n", cmd);
 170                         usage(git_usage_string);
 171                 }
 172
 173                 (*argv)++;
 174                 (*argc)--;
 175         }
 176         return (*argv) - orig_argv;
 177 }
 178
 179 static int handle_alias(int *argcp, const char ***argv)
 180 {
 181         int envchanged = 0, ret = 0, saved_errno = errno;
 182         const char *subdir;
 183         int count, option_count;
 184         const char **new_argv;
 185         const char *alias_command;
 186         char *alias_string;
 187         int unused_nongit;
 188
 189         subdir = setup_git_directory_gently(&unused_nongit);
 190
 191         alias_command = (*argv)[0];
 192         alias_string = alias_lookup(alias_command);
 193         if (alias_string) {
 194                 if (alias_string[0] == '!') {
 195                         const char **alias_argv;
 196                         int argc = *argcp, i;
 197
 198                         commit_pager_choice();
 199
 200                         /* build alias_argv */
 201                         alias_argv = xmalloc(sizeof(*alias_argv) * (argc + 1));
 202                         alias_argv[0] = alias_string + 1;
 203                         for (i = 1; i < argc; ++i)
 204                                 alias_argv[i] = (*argv)[i];
 205                         alias_argv[argc] = NULL;
 206
 207                         ret = run_command_v_opt(alias_argv, RUN_USING_SHELL);
 208                         if (ret >= 0)   /* normal exit */
 209                                 exit(ret);
 210
 211                         die_errno("While expanding alias '%s': '%s'",
 212                             alias_command, alias_string + 1);
 213                 }
 214                 count = split_cmdline(alias_string, &new_argv);
 215                 if (count < 0)
 216                         die("Bad alias.%s string: %s", alias_command,
 217                             split_cmdline_strerror(count));
 218                 option_count = handle_options(&new_argv, &count, &envchanged);
 219                 if (envchanged)
 220                         die("alias '%s' changes environment variables\n"
 221                                  "You can use '!git' in the alias to do this.",
 222                                  alias_command);
 223                 memmove(new_argv - option_count, new_argv,
 224                                 count * sizeof(char *));
 225                 new_argv -= option_count;
 226
 227                 if (count < 1)
 228                         die("empty alias for %s", alias_command);
 229
 230                 if (!strcmp(alias_command, new_argv[0]))
 231                         die("recursive alias: %s", alias_command);
 232
 233                 trace_argv_printf(new_argv,
 234                                   "trace: alias expansion: %s =>",
 235                                   alias_command);
 236
 237                 new_argv = xrealloc(new_argv, sizeof(char *) *
 238                                     (count + *argcp));
 239                 /* insert after command name */
 240                 memcpy(new_argv + count, *argv + 1, sizeof(char *) * *argcp);
 241
 242                 *argv = new_argv;
 243                 *argcp += count - 1;
 244
 245                 ret = 1;
 246         }
 247
 248         if (subdir && chdir(subdir))
 249                 die_errno("Cannot change to '%s'", subdir);
 250
 251         errno = saved_errno;
 252
 253         return ret;
 254 }
 255
 256 #define RUN_SETUP               (1<<0)
 257 #define RUN_SETUP_GENTLY        (1<<1)
 258 #define USE_PAGER               (1<<2)
 259 /*
 260  * require working tree to be present -- anything uses this needs
 261  * RUN_SETUP for reading from the configuration file.
 262  */
 263 #define NEED_WORK_TREE          (1<<3)
 264
 265 struct cmd_struct {
 266         const char *cmd;
 267         int (*fn)(int, const char **, const char *);
 268         int option;
 269 };
 270
 271 static int run_builtin(struct cmd_struct *p, int argc, const char **argv)
 272 {
 273         int status, help;
 274         struct stat st;
 275         const char *prefix;
 276
 277         prefix = NULL;
 278         help = argc == 2 && !strcmp(argv[1], "-h");
 279         if (!help) {
 280                 if (p->option & RUN_SETUP)
 281                         prefix = setup_git_directory();
 282                 if (p->option & RUN_SETUP_GENTLY) {
 283                         int nongit_ok;
 284                         prefix = setup_git_directory_gently(&nongit_ok);
 285                 }
 286
 287                 if (use_pager == -1 && p->option & (RUN_SETUP | RUN_SETUP_GENTLY))
 288                         use_pager = check_pager_config(p->cmd);
 289                 if (use_pager == -1 && p->option & USE_PAGER)
 290                         use_pager = 1;
 291
 292                 if ((p->option & (RUN_SETUP | RUN_SETUP_GENTLY)) &&
 293                     startup_info->have_repository) /* get_git_dir() may set up repo, avoid that */
 294                         trace_repo_setup(prefix);
 295         }
 296         commit_pager_choice();
 297
 298         if (!help && p->option & NEED_WORK_TREE)
 299                 setup_work_tree();
 300
 301         trace_argv_printf(argv, "trace: built-in: git");
 302
 303         status = p->fn(argc, argv, prefix);
 304         if (status)
 305                 return status;
 306
 307         /* Somebody closed stdout? */
 308         if (fstat(fileno(stdout), &st))
 309                 return 0;
 310         /* Ignore write errors for pipes and sockets.. */
 311         if (S_ISFIFO(st.st_mode) || S_ISSOCK(st.st_mode))
 312                 return 0;
 313
 314         /* Check for ENOSPC and EIO errors.. */
 315         if (fflush(stdout))
 316                 die_errno("write failure on standard output");
 317         if (ferror(stdout))
 318                 die("unknown write failure on standard output");
 319         if (fclose(stdout))
 320                 die_errno("close failed on standard output");
 321         return 0;
 322 }
 323
 324 static void handle_internal_command(int argc, const char **argv)
 325 {
 326         const char *cmd = argv[0];
 327         static struct cmd_struct commands[] = {
 328                 { "add", cmd_add, RUN_SETUP | NEED_WORK_TREE },
 329                 { "annotate", cmd_annotate, RUN_SETUP },
 330                 { "apply", cmd_apply, RUN_SETUP_GENTLY },
 331                 { "archive", cmd_archive },
 332                 { "bisect--helper", cmd_bisect__helper, RUN_SETUP },
 333                 { "blame", cmd_blame, RUN_SETUP },
 334                 { "branch", cmd_branch, RUN_SETUP },
 335                 { "bundle", cmd_bundle, RUN_SETUP_GENTLY },
 336                 { "cat-file", cmd_cat_file, RUN_SETUP },
 337                 { "check-attr", cmd_check_attr, RUN_SETUP },
 338                 { "check-ignore", cmd_check_ignore, RUN_SETUP | NEED_WORK_TREE },
 339                 { "check-ref-format", cmd_check_ref_format },
 340                 { "checkout", cmd_checkout, RUN_SETUP | NEED_WORK_TREE },
 341                 { "checkout-index", cmd_checkout_index,
 342                         RUN_SETUP | NEED_WORK_TREE},
 343                 { "cherry", cmd_cherry, RUN_SETUP },
 344                 { "cherry-pick", cmd_cherry_pick, RUN_SETUP | NEED_WORK_TREE },
 345                 { "clean", cmd_clean, RUN_SETUP | NEED_WORK_TREE },
 346                 { "clone", cmd_clone },
 347                 { "column", cmd_column, RUN_SETUP_GENTLY },
 348                 { "commit", cmd_commit, RUN_SETUP | NEED_WORK_TREE },
 349                 { "commit-tree", cmd_commit_tree, RUN_SETUP },
 350                 { "config", cmd_config, RUN_SETUP_GENTLY },
 351                 { "count-objects", cmd_count_objects, RUN_SETUP },
 352                 { "credential", cmd_credential, RUN_SETUP_GENTLY },
 353                 { "describe", cmd_describe, RUN_SETUP },
 354                 { "diff", cmd_diff },
 355                 { "diff-files", cmd_diff_files, RUN_SETUP | NEED_WORK_TREE },
 356                 { "diff-index", cmd_diff_index, RUN_SETUP },
 357                 { "diff-tree", cmd_diff_tree, RUN_SETUP },
 358                 { "fast-export", cmd_fast_export, RUN_SETUP },
 359                 { "fetch", cmd_fetch, RUN_SETUP },
 360                 { "fetch-pack", cmd_fetch_pack, RUN_SETUP },
 361                 { "fmt-merge-msg", cmd_fmt_merge_msg, RUN_SETUP },
 362                 { "for-each-ref", cmd_for_each_ref, RUN_SETUP },
 363                 { "format-patch", cmd_format_patch, RUN_SETUP },
 364                 { "fsck", cmd_fsck, RUN_SETUP },
 365                 { "fsck-objects", cmd_fsck, RUN_SETUP },
 366                 { "gc", cmd_gc, RUN_SETUP },
 367                 { "get-tar-commit-id", cmd_get_tar_commit_id },
 368                 { "grep", cmd_grep, RUN_SETUP_GENTLY },
 369                 { "hash-object", cmd_hash_object },
 370                 { "help", cmd_help },
 371                 { "index-pack", cmd_index_pack, RUN_SETUP_GENTLY },
 372                 { "init", cmd_init_db },
 373                 { "init-db", cmd_init_db },
 374                 { "log", cmd_log, RUN_SETUP },
 375                 { "ls-files", cmd_ls_files, RUN_SETUP },
 376                 { "ls-remote", cmd_ls_remote, RUN_SETUP_GENTLY },
 377                 { "ls-tree", cmd_ls_tree, RUN_SETUP },
 378                 { "mailinfo", cmd_mailinfo },
 379                 { "mailsplit", cmd_mailsplit },
 380                 { "merge", cmd_merge, RUN_SETUP | NEED_WORK_TREE },
 381                 { "merge-base", cmd_merge_base, RUN_SETUP },
 382                 { "merge-file", cmd_merge_file, RUN_SETUP_GENTLY },
 383                 { "merge-index", cmd_merge_index, RUN_SETUP },
 384                 { "merge-ours", cmd_merge_ours, RUN_SETUP },
 385                 { "merge-recursive", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE },
 386                 { "merge-recursive-ours", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE },
 387                 { "merge-recursive-theirs", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE },
 388                 { "merge-subtree", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE },
 389                 { "merge-tree", cmd_merge_tree, RUN_SETUP },
 390                 { "mktag", cmd_mktag, RUN_SETUP },
 391                 { "mktree", cmd_mktree, RUN_SETUP },
 392                 { "mv", cmd_mv, RUN_SETUP | NEED_WORK_TREE },
 393                 { "name-rev", cmd_name_rev, RUN_SETUP },
 394                 { "notes", cmd_notes, RUN_SETUP },
 395                 { "pack-objects", cmd_pack_objects, RUN_SETUP },
 396                 { "pack-redundant", cmd_pack_redundant, RUN_SETUP },
 397                 { "pack-refs", cmd_pack_refs, RUN_SETUP },
 398                 { "patch-id", cmd_patch_id },
 399                 { "peek-remote", cmd_ls_remote, RUN_SETUP_GENTLY },
 400                 { "pickaxe", cmd_blame, RUN_SETUP },
 401                 { "prune", cmd_prune, RUN_SETUP },
 402                 { "prune-packed", cmd_prune_packed, RUN_SETUP },
 403                 { "push", cmd_push, RUN_SETUP },
 404                 { "read-tree", cmd_read_tree, RUN_SETUP },
 405                 { "receive-pack", cmd_receive_pack },
 406                 { "reflog", cmd_reflog, RUN_SETUP },
 407                 { "remote", cmd_remote, RUN_SETUP },
 408                 { "remote-ext", cmd_remote_ext },
 409                 { "remote-fd", cmd_remote_fd },
 410                 { "replace", cmd_replace, RUN_SETUP },
 411                 { "repo-config", cmd_repo_config, RUN_SETUP_GENTLY },
 412                 { "rerere", cmd_rerere, RUN_SETUP },
 413                 { "reset", cmd_reset, RUN_SETUP },
 414                 { "rev-list", cmd_rev_list, RUN_SETUP },
 415                 { "rev-parse", cmd_rev_parse },
 416                 { "revert", cmd_revert, RUN_SETUP | NEED_WORK_TREE },
 417                 { "rm", cmd_rm, RUN_SETUP },
 418                 { "send-pack", cmd_send_pack, RUN_SETUP },
 419                 { "shortlog", cmd_shortlog, RUN_SETUP_GENTLY | USE_PAGER },
 420                 { "show", cmd_show, RUN_SETUP },
 421                 { "show-branch", cmd_show_branch, RUN_SETUP },
 422                 { "show-ref", cmd_show_ref, RUN_SETUP },
 423                 { "stage", cmd_add, RUN_SETUP | NEED_WORK_TREE },
 424                 { "status", cmd_status, RUN_SETUP | NEED_WORK_TREE },
 425                 { "stripspace", cmd_stripspace },
 426                 { "symbolic-ref", cmd_symbolic_ref, RUN_SETUP },
 427                 { "tag", cmd_tag, RUN_SETUP },
 428                 { "tar-tree", cmd_tar_tree },
 429                 { "unpack-file", cmd_unpack_file, RUN_SETUP },
 430                 { "unpack-objects", cmd_unpack_objects, RUN_SETUP },
 431                 { "update-index", cmd_update_index, RUN_SETUP },
 432                 { "update-ref", cmd_update_ref, RUN_SETUP },
 433                 { "update-server-info", cmd_update_server_info, RUN_SETUP },
 434                 { "upload-archive", cmd_upload_archive },
 435                 { "upload-archive--writer", cmd_upload_archive_writer },
 436                 { "var", cmd_var, RUN_SETUP_GENTLY },
 437                 { "verify-pack", cmd_verify_pack },
 438                 { "verify-tag", cmd_verify_tag, RUN_SETUP },
 439                 { "version", cmd_version },
 440                 { "whatchanged", cmd_whatchanged, RUN_SETUP },
 441                 { "write-tree", cmd_write_tree, RUN_SETUP },
 442         };
 443         int i;
 444         static const char ext[] = STRIP_EXTENSION;
 445
 446         if (sizeof(ext) > 1) {
 447                 i = strlen(argv[0]) - strlen(ext);
 448                 if (i > 0 && !strcmp(argv[0] + i, ext)) {
 449                         char *argv0 = xstrdup(argv[0]);
 450                         argv[0] = cmd = argv0;
 451                         argv0[i] = '\0';
 452                 }
 453         }
 454
 455         /* Turn "git cmd --help" into "git help cmd" */
 456         if (argc > 1 && !strcmp(argv[1], "--help")) {
 457                 argv[1] = argv[0];
 458                 argv[0] = cmd = "help";
 459         }
 460
 461         for (i = 0; i < ARRAY_SIZE(commands); i++) {
 462                 struct cmd_struct *p = commands+i;
 463                 if (strcmp(p->cmd, cmd))
 464                         continue;
 465                 exit(run_builtin(p, argc, argv));
 466         }
 467 }
 468
 469 static void execv_dashed_external(const char **argv)
 470 {
 471         struct strbuf cmd = STRBUF_INIT;
 472         const char *tmp;
 473         int status;
 474
 475         if (use_pager == -1)
 476                 use_pager = check_pager_config(argv[0]);
 477         commit_pager_choice();
 478
 479         strbuf_addf(&cmd, "git-%s", argv[0]);
 480
 481         /*
 482          * argv[0] must be the git command, but the argv array
 483          * belongs to the caller, and may be reused in
 484          * subsequent loop iterations. Save argv[0] and
 485          * restore it on error.
 486          */
 487         tmp = argv[0];
 488         argv[0] = cmd.buf;
 489
 490         trace_argv_printf(argv, "trace: exec:");
 491
 492         /*
 493          * if we fail because the command is not found, it is
 494          * OK to return. Otherwise, we just pass along the status code.
 495          */
 496         status = run_command_v_opt(argv, RUN_SILENT_EXEC_FAILURE | RUN_CLEAN_ON_EXIT);
 497         if (status >= 0 || errno != ENOENT)
 498                 exit(status);
 499
 500         argv[0] = tmp;
 501
 502         strbuf_release(&cmd);
 503 }
 504
 505 static int run_argv(int *argcp, const char ***argv)
 506 {
 507         int done_alias = 0;
 508
 509         while (1) {
 510                 /* See if it's an internal command */
 511                 handle_internal_command(*argcp, *argv);
 512
 513                 /* .. then try the external ones */
 514                 execv_dashed_external(*argv);
 515
 516                 /* It could be an alias -- this works around the insanity
 517                  * of overriding "git log" with "git show" by having
 518                  * alias.log = show
 519                  */
 520                 if (done_alias || !handle_alias(argcp, argv))
 521                         break;
 522                 done_alias = 1;
 523         }
 524
 525         return done_alias;
 526 }
 527
 528
 529 int main(int argc, char **av)
 530 {
 531         const char **argv = (const char **) av;
 532         const char *cmd;
 533
 534         startup_info = &git_startup_info;
 535
 536         cmd = git_extract_argv0_path(argv[0]);
 537         if (!cmd)
 538                 cmd = "git-help";
 539
 540         git_setup_gettext();
 541
 542         /*
 543          * "git-xxxx" is the same as "git xxxx", but we obviously:
 544          *
 545          *  - cannot take flags in between the "git" and the "xxxx".
 546          *  - cannot execute it externally (since it would just do
 547          *    the same thing over again)
 548          *
 549          * So we just directly call the internal command handler, and
 550          * die if that one cannot handle it.
 551          */
 552         if (!prefixcmp(cmd, "git-")) {
 553                 cmd += 4;
 554                 argv[0] = cmd;
 555                 handle_internal_command(argc, argv);
 556                 die("cannot handle %s internally", cmd);
 557         }
 558
 559         /* Look for flags.. */
 560         argv++;
 561         argc--;
 562         handle_options(&argv, &argc, NULL);
 563         if (argc > 0) {
 564                 if (!prefixcmp(argv[0], "--"))
 565                         argv[0] += 2;
 566         } else {
 567                 /* The user didn't specify a command; give them help */
 568                 commit_pager_choice();
 569                 printf("usage: %s\n\n", git_usage_string);
 570                 list_common_cmds_help();
 571                 printf("\n%s\n", _(git_more_info_string));
 572                 exit(1);
 573         }
 574         cmd = argv[0];
 575
 576         /*
 577          * We use PATH to find git commands, but we prepend some higher
 578          * precedence paths: the "--exec-path" option, the GIT_EXEC_PATH
 579          * environment, and the $(gitexecdir) from the Makefile at build
 580          * time.
 581          */
 582         setup_path();
 583
 584         while (1) {
 585                 static int done_help = 0;
 586                 static int was_alias = 0;
 587                 was_alias = run_argv(&argc, &argv);
 588                 if (errno != ENOENT)
 589                         break;
 590                 if (was_alias) {
 591                         fprintf(stderr, "Expansion of alias '%s' failed; "
 592                                 "'%s' is not a git command\n",
 593                                 cmd, argv[0]);
 594                         exit(1);
 595                 }
 596                 if (!done_help) {
 597                         cmd = argv[0] = help_unknown_cmd(cmd);
 598                         done_help = 1;
 599                 } else
 600                         break;
 601         }
 602
 603         fprintf(stderr, "Failed to run command '%s': %s\n",
 604                 cmd, strerror(errno));
 605
 606         return 1;
 607 }