git.c

   1 #include "builtin.h"
   2 #include "exec_cmd.h"
   3 #include "help.h"
   4 #include "run-command.h"
   5
   6 const 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
  13 const 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
  18 static int use_pager = -1;
  19 static char *orig_cwd;
  20 static const char *env_names[] = {
  21         GIT_DIR_ENVIRONMENT,
  22         GIT_WORK_TREE_ENVIRONMENT,
  23         GIT_IMPLICIT_WORK_TREE_ENVIRONMENT,
  24         GIT_PREFIX_ENVIRONMENT
  25 };
  26 static char *orig_env[4];
  27 static int save_restore_env_balance;
  28
  29 static 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
  42 static 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
  64 static 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
  77 static 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
 232 static 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
 313 struct cmd_struct {
 314         const char *cmd;
 315         int (*fn)(int, const char **, const char *);
 316         int option;
 317 };
 318
 319 static 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
 372 static 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
 494 static 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
 505 int is_builtin(const char *s)
 506 {
 507         return !!get_builtin(s);
 508 }
 509
 510 #ifdef STRIP_EXTENSION
 511 static 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
 522 static 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
 541 static 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
 577 static 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
 611 int 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         else {
 620                 const char *slash = find_last_dir_sep(cmd);
 621                 if (slash)
 622                         cmd = slash + 1;
 623         }
 624
 625         trace_command_performance(argv);
 626
 627         /*
 628          * "git-xxxx" is the same as "git xxxx", but we obviously:
 629          *
 630          *  - cannot take flags in between the "git" and the "xxxx".
 631          *  - cannot execute it externally (since it would just do
 632          *    the same thing over again)
 633          *
 634          * So we just directly call the builtin handler, and die if
 635          * that one cannot handle it.
 636          */
 637         if (skip_prefix(cmd, "git-", &cmd)) {
 638                 argv[0] = cmd;
 639                 handle_builtin(argc, argv);
 640                 die("cannot handle %s as a builtin", cmd);
 641         }
 642
 643         /* Look for flags.. */
 644         argv++;
 645         argc--;
 646         handle_options(&argv, &argc, NULL);
 647         if (argc > 0) {
 648                 /* translate --help and --version into commands */
 649                 skip_prefix(argv[0], "--", &argv[0]);
 650         } else {
 651                 /* The user didn't specify a command; give them help */
 652                 commit_pager_choice();
 653                 printf("usage: %s\n\n", git_usage_string);
 654                 list_common_cmds_help();
 655                 printf("\n%s\n", _(git_more_info_string));
 656                 exit(1);
 657         }
 658         cmd = argv[0];
 659
 660         /*
 661          * We use PATH to find git commands, but we prepend some higher
 662          * precedence paths: the "--exec-path" option, the GIT_EXEC_PATH
 663          * environment, and the $(gitexecdir) from the Makefile at build
 664          * time.
 665          */
 666         setup_path();
 667
 668         while (1) {
 669                 int was_alias = run_argv(&argc, &argv);
 670                 if (errno != ENOENT)
 671                         break;
 672                 if (was_alias) {
 673                         fprintf(stderr, "Expansion of alias '%s' failed; "
 674                                 "'%s' is not a git command\n",
 675                                 cmd, argv[0]);
 676                         exit(1);
 677                 }
 678                 if (!done_help) {
 679                         cmd = argv[0] = help_unknown_cmd(cmd);
 680                         done_help = 1;
 681                 } else
 682                         break;
 683         }
 684
 685         fprintf(stderr, "Failed to run command '%s': %s\n",
 686                 cmd, strerror(errno));
 687
 688         return 1;
 689 }