git: support --list-cmds=list-<category>
[git] / git.c
1 #include "builtin.h"
2 #include "config.h"
3 #include "exec_cmd.h"
4 #include "help.h"
5 #include "run-command.h"
6
7 #define RUN_SETUP               (1<<0)
8 #define RUN_SETUP_GENTLY        (1<<1)
9 #define USE_PAGER               (1<<2)
10 /*
11  * require working tree to be present -- anything uses this needs
12  * RUN_SETUP for reading from the configuration file.
13  */
14 #define NEED_WORK_TREE          (1<<3)
15 #define SUPPORT_SUPER_PREFIX    (1<<4)
16 #define DELAY_PAGER_CONFIG      (1<<5)
17 #define NO_PARSEOPT             (1<<6) /* parse-options is not used */
18
19 struct cmd_struct {
20         const char *cmd;
21         int (*fn)(int, const char **, const char *);
22         unsigned int option;
23 };
24
25 const char git_usage_string[] =
26         N_("git [--version] [--help] [-C <path>] [-c <name>=<value>]\n"
27            "           [--exec-path[=<path>]] [--html-path] [--man-path] [--info-path]\n"
28            "           [-p | --paginate | --no-pager] [--no-replace-objects] [--bare]\n"
29            "           [--git-dir=<path>] [--work-tree=<path>] [--namespace=<name>]\n"
30            "           <command> [<args>]");
31
32 const char git_more_info_string[] =
33         N_("'git help -a' and 'git help -g' list available subcommands and some\n"
34            "concept guides. See 'git help <command>' or 'git help <concept>'\n"
35            "to read about a specific subcommand or concept.");
36
37 static int use_pager = -1;
38
39 static void list_builtins(struct string_list *list, unsigned int exclude_option);
40
41 static int match_token(const char *spec, int len, const char *token)
42 {
43         int token_len = strlen(token);
44
45         return len == token_len && !strncmp(spec, token, token_len);
46 }
47
48 static int list_cmds(const char *spec)
49 {
50         struct string_list list = STRING_LIST_INIT_DUP;
51         int i;
52
53         while (*spec) {
54                 const char *sep = strchrnul(spec, ',');
55                 int len = sep - spec;
56
57                 if (match_token(spec, len, "builtins"))
58                         list_builtins(&list, 0);
59                 else if (match_token(spec, len, "main"))
60                         list_all_main_cmds(&list);
61                 else if (match_token(spec, len, "others"))
62                         list_all_other_cmds(&list);
63                 else if (len > 5 && !strncmp(spec, "list-", 5)) {
64                         struct strbuf sb = STRBUF_INIT;
65
66                         strbuf_add(&sb, spec + 5, len - 5);
67                         list_cmds_by_category(&list, sb.buf);
68                         strbuf_release(&sb);
69                 }
70                 else
71                         die(_("unsupported command listing type '%s'"), spec);
72                 spec += len;
73                 if (*spec == ',')
74                         spec++;
75         }
76         for (i = 0; i < list.nr; i++)
77                 puts(list.items[i].string);
78         string_list_clear(&list, 0);
79         return 0;
80 }
81
82 static void commit_pager_choice(void) {
83         switch (use_pager) {
84         case 0:
85                 setenv("GIT_PAGER", "cat", 1);
86                 break;
87         case 1:
88                 setup_pager();
89                 break;
90         default:
91                 break;
92         }
93 }
94
95 void setup_auto_pager(const char *cmd, int def)
96 {
97         if (use_pager != -1 || pager_in_use())
98                 return;
99         use_pager = check_pager_config(cmd);
100         if (use_pager == -1)
101                 use_pager = def;
102         commit_pager_choice();
103 }
104
105 static int handle_options(const char ***argv, int *argc, int *envchanged)
106 {
107         const char **orig_argv = *argv;
108
109         while (*argc > 0) {
110                 const char *cmd = (*argv)[0];
111                 if (cmd[0] != '-')
112                         break;
113
114                 /*
115                  * For legacy reasons, the "version" and "help"
116                  * commands can be written with "--" prepended
117                  * to make them look like flags.
118                  */
119                 if (!strcmp(cmd, "--help") || !strcmp(cmd, "--version"))
120                         break;
121
122                 /*
123                  * Check remaining flags.
124                  */
125                 if (skip_prefix(cmd, "--exec-path", &cmd)) {
126                         if (*cmd == '=')
127                                 git_set_argv_exec_path(cmd + 1);
128                         else {
129                                 puts(git_exec_path());
130                                 exit(0);
131                         }
132                 } else if (!strcmp(cmd, "--html-path")) {
133                         puts(system_path(GIT_HTML_PATH));
134                         exit(0);
135                 } else if (!strcmp(cmd, "--man-path")) {
136                         puts(system_path(GIT_MAN_PATH));
137                         exit(0);
138                 } else if (!strcmp(cmd, "--info-path")) {
139                         puts(system_path(GIT_INFO_PATH));
140                         exit(0);
141                 } else if (!strcmp(cmd, "-p") || !strcmp(cmd, "--paginate")) {
142                         use_pager = 1;
143                 } else if (!strcmp(cmd, "--no-pager")) {
144                         use_pager = 0;
145                         if (envchanged)
146                                 *envchanged = 1;
147                 } else if (!strcmp(cmd, "--no-replace-objects")) {
148                         check_replace_refs = 0;
149                         setenv(NO_REPLACE_OBJECTS_ENVIRONMENT, "1", 1);
150                         if (envchanged)
151                                 *envchanged = 1;
152                 } else if (!strcmp(cmd, "--git-dir")) {
153                         if (*argc < 2) {
154                                 fprintf(stderr, _("no directory given for --git-dir\n" ));
155                                 usage(git_usage_string);
156                         }
157                         setenv(GIT_DIR_ENVIRONMENT, (*argv)[1], 1);
158                         if (envchanged)
159                                 *envchanged = 1;
160                         (*argv)++;
161                         (*argc)--;
162                 } else if (skip_prefix(cmd, "--git-dir=", &cmd)) {
163                         setenv(GIT_DIR_ENVIRONMENT, cmd, 1);
164                         if (envchanged)
165                                 *envchanged = 1;
166                 } else if (!strcmp(cmd, "--namespace")) {
167                         if (*argc < 2) {
168                                 fprintf(stderr, _("no namespace given for --namespace\n" ));
169                                 usage(git_usage_string);
170                         }
171                         setenv(GIT_NAMESPACE_ENVIRONMENT, (*argv)[1], 1);
172                         if (envchanged)
173                                 *envchanged = 1;
174                         (*argv)++;
175                         (*argc)--;
176                 } else if (skip_prefix(cmd, "--namespace=", &cmd)) {
177                         setenv(GIT_NAMESPACE_ENVIRONMENT, cmd, 1);
178                         if (envchanged)
179                                 *envchanged = 1;
180                 } else if (!strcmp(cmd, "--work-tree")) {
181                         if (*argc < 2) {
182                                 fprintf(stderr, _("no directory given for --work-tree\n" ));
183                                 usage(git_usage_string);
184                         }
185                         setenv(GIT_WORK_TREE_ENVIRONMENT, (*argv)[1], 1);
186                         if (envchanged)
187                                 *envchanged = 1;
188                         (*argv)++;
189                         (*argc)--;
190                 } else if (skip_prefix(cmd, "--work-tree=", &cmd)) {
191                         setenv(GIT_WORK_TREE_ENVIRONMENT, cmd, 1);
192                         if (envchanged)
193                                 *envchanged = 1;
194                 } else if (!strcmp(cmd, "--super-prefix")) {
195                         if (*argc < 2) {
196                                 fprintf(stderr, _("no prefix given for --super-prefix\n" ));
197                                 usage(git_usage_string);
198                         }
199                         setenv(GIT_SUPER_PREFIX_ENVIRONMENT, (*argv)[1], 1);
200                         if (envchanged)
201                                 *envchanged = 1;
202                         (*argv)++;
203                         (*argc)--;
204                 } else if (skip_prefix(cmd, "--super-prefix=", &cmd)) {
205                         setenv(GIT_SUPER_PREFIX_ENVIRONMENT, cmd, 1);
206                         if (envchanged)
207                                 *envchanged = 1;
208                 } else if (!strcmp(cmd, "--bare")) {
209                         char *cwd = xgetcwd();
210                         is_bare_repository_cfg = 1;
211                         setenv(GIT_DIR_ENVIRONMENT, cwd, 0);
212                         free(cwd);
213                         setenv(GIT_IMPLICIT_WORK_TREE_ENVIRONMENT, "0", 1);
214                         if (envchanged)
215                                 *envchanged = 1;
216                 } else if (!strcmp(cmd, "-c")) {
217                         if (*argc < 2) {
218                                 fprintf(stderr, _("-c expects a configuration string\n" ));
219                                 usage(git_usage_string);
220                         }
221                         git_config_push_parameter((*argv)[1]);
222                         (*argv)++;
223                         (*argc)--;
224                 } else if (!strcmp(cmd, "--literal-pathspecs")) {
225                         setenv(GIT_LITERAL_PATHSPECS_ENVIRONMENT, "1", 1);
226                         if (envchanged)
227                                 *envchanged = 1;
228                 } else if (!strcmp(cmd, "--no-literal-pathspecs")) {
229                         setenv(GIT_LITERAL_PATHSPECS_ENVIRONMENT, "0", 1);
230                         if (envchanged)
231                                 *envchanged = 1;
232                 } else if (!strcmp(cmd, "--glob-pathspecs")) {
233                         setenv(GIT_GLOB_PATHSPECS_ENVIRONMENT, "1", 1);
234                         if (envchanged)
235                                 *envchanged = 1;
236                 } else if (!strcmp(cmd, "--noglob-pathspecs")) {
237                         setenv(GIT_NOGLOB_PATHSPECS_ENVIRONMENT, "1", 1);
238                         if (envchanged)
239                                 *envchanged = 1;
240                 } else if (!strcmp(cmd, "--icase-pathspecs")) {
241                         setenv(GIT_ICASE_PATHSPECS_ENVIRONMENT, "1", 1);
242                         if (envchanged)
243                                 *envchanged = 1;
244                 } else if (!strcmp(cmd, "--no-optional-locks")) {
245                         setenv(GIT_OPTIONAL_LOCKS_ENVIRONMENT, "0", 1);
246                         if (envchanged)
247                                 *envchanged = 1;
248                 } else if (!strcmp(cmd, "--shallow-file")) {
249                         (*argv)++;
250                         (*argc)--;
251                         set_alternate_shallow_file((*argv)[0], 1);
252                         if (envchanged)
253                                 *envchanged = 1;
254                 } else if (!strcmp(cmd, "-C")) {
255                         if (*argc < 2) {
256                                 fprintf(stderr, _("no directory given for -C\n" ));
257                                 usage(git_usage_string);
258                         }
259                         if ((*argv)[1][0]) {
260                                 if (chdir((*argv)[1]))
261                                         die_errno("cannot change to '%s'", (*argv)[1]);
262                                 if (envchanged)
263                                         *envchanged = 1;
264                         }
265                         (*argv)++;
266                         (*argc)--;
267                 } else if (skip_prefix(cmd, "--list-cmds=", &cmd)) {
268                         if (!strcmp(cmd, "parseopt")) {
269                                 struct string_list list = STRING_LIST_INIT_DUP;
270                                 int i;
271
272                                 list_builtins(&list, NO_PARSEOPT);
273                                 for (i = 0; i < list.nr; i++)
274                                         printf("%s ", list.items[i].string);
275                                 string_list_clear(&list, 0);
276                                 exit(0);
277                         } else {
278                                 exit(list_cmds(cmd));
279                         }
280                 } else {
281                         fprintf(stderr, _("unknown option: %s\n"), cmd);
282                         usage(git_usage_string);
283                 }
284
285                 (*argv)++;
286                 (*argc)--;
287         }
288         return (*argv) - orig_argv;
289 }
290
291 static int handle_alias(int *argcp, const char ***argv)
292 {
293         int envchanged = 0, ret = 0, saved_errno = errno;
294         int count, option_count;
295         const char **new_argv;
296         const char *alias_command;
297         char *alias_string;
298
299         alias_command = (*argv)[0];
300         alias_string = alias_lookup(alias_command);
301         if (alias_string) {
302                 if (alias_string[0] == '!') {
303                         struct child_process child = CHILD_PROCESS_INIT;
304                         int nongit_ok;
305
306                         /* Aliases expect GIT_PREFIX, GIT_DIR etc to be set */
307                         setup_git_directory_gently(&nongit_ok);
308
309                         commit_pager_choice();
310
311                         child.use_shell = 1;
312                         argv_array_push(&child.args, alias_string + 1);
313                         argv_array_pushv(&child.args, (*argv) + 1);
314
315                         ret = run_command(&child);
316                         if (ret >= 0)   /* normal exit */
317                                 exit(ret);
318
319                         die_errno("while expanding alias '%s': '%s'",
320                             alias_command, alias_string + 1);
321                 }
322                 count = split_cmdline(alias_string, &new_argv);
323                 if (count < 0)
324                         die("Bad alias.%s string: %s", alias_command,
325                             split_cmdline_strerror(count));
326                 option_count = handle_options(&new_argv, &count, &envchanged);
327                 if (envchanged)
328                         die("alias '%s' changes environment variables.\n"
329                                  "You can use '!git' in the alias to do this",
330                                  alias_command);
331                 memmove(new_argv - option_count, new_argv,
332                                 count * sizeof(char *));
333                 new_argv -= option_count;
334
335                 if (count < 1)
336                         die("empty alias for %s", alias_command);
337
338                 if (!strcmp(alias_command, new_argv[0]))
339                         die("recursive alias: %s", alias_command);
340
341                 trace_argv_printf(new_argv,
342                                   "trace: alias expansion: %s =>",
343                                   alias_command);
344
345                 REALLOC_ARRAY(new_argv, count + *argcp);
346                 /* insert after command name */
347                 memcpy(new_argv + count, *argv + 1, sizeof(char *) * *argcp);
348
349                 *argv = new_argv;
350                 *argcp += count - 1;
351
352                 ret = 1;
353         }
354
355         errno = saved_errno;
356
357         return ret;
358 }
359
360 static int run_builtin(struct cmd_struct *p, int argc, const char **argv)
361 {
362         int status, help;
363         struct stat st;
364         const char *prefix;
365
366         prefix = NULL;
367         help = argc == 2 && !strcmp(argv[1], "-h");
368         if (!help) {
369                 if (p->option & RUN_SETUP)
370                         prefix = setup_git_directory();
371                 else if (p->option & RUN_SETUP_GENTLY) {
372                         int nongit_ok;
373                         prefix = setup_git_directory_gently(&nongit_ok);
374                 }
375
376                 if (use_pager == -1 && p->option & (RUN_SETUP | RUN_SETUP_GENTLY) &&
377                     !(p->option & DELAY_PAGER_CONFIG))
378                         use_pager = check_pager_config(p->cmd);
379                 if (use_pager == -1 && p->option & USE_PAGER)
380                         use_pager = 1;
381
382                 if ((p->option & (RUN_SETUP | RUN_SETUP_GENTLY)) &&
383                     startup_info->have_repository) /* get_git_dir() may set up repo, avoid that */
384                         trace_repo_setup(prefix);
385         }
386         commit_pager_choice();
387
388         if (!help && get_super_prefix()) {
389                 if (!(p->option & SUPPORT_SUPER_PREFIX))
390                         die("%s doesn't support --super-prefix", p->cmd);
391         }
392
393         if (!help && p->option & NEED_WORK_TREE)
394                 setup_work_tree();
395
396         trace_argv_printf(argv, "trace: built-in: git");
397
398         status = p->fn(argc, argv, prefix);
399         if (status)
400                 return status;
401
402         /* Somebody closed stdout? */
403         if (fstat(fileno(stdout), &st))
404                 return 0;
405         /* Ignore write errors for pipes and sockets.. */
406         if (S_ISFIFO(st.st_mode) || S_ISSOCK(st.st_mode))
407                 return 0;
408
409         /* Check for ENOSPC and EIO errors.. */
410         if (fflush(stdout))
411                 die_errno("write failure on standard output");
412         if (ferror(stdout))
413                 die("unknown write failure on standard output");
414         if (fclose(stdout))
415                 die_errno("close failed on standard output");
416         return 0;
417 }
418
419 static struct cmd_struct commands[] = {
420         { "add", cmd_add, RUN_SETUP | NEED_WORK_TREE },
421         { "am", cmd_am, RUN_SETUP | NEED_WORK_TREE },
422         { "annotate", cmd_annotate, RUN_SETUP | NO_PARSEOPT },
423         { "apply", cmd_apply, RUN_SETUP_GENTLY },
424         { "archive", cmd_archive, RUN_SETUP_GENTLY },
425         { "bisect--helper", cmd_bisect__helper, RUN_SETUP },
426         { "blame", cmd_blame, RUN_SETUP },
427         { "branch", cmd_branch, RUN_SETUP | DELAY_PAGER_CONFIG },
428         { "bundle", cmd_bundle, RUN_SETUP_GENTLY | NO_PARSEOPT },
429         { "cat-file", cmd_cat_file, RUN_SETUP },
430         { "check-attr", cmd_check_attr, RUN_SETUP },
431         { "check-ignore", cmd_check_ignore, RUN_SETUP | NEED_WORK_TREE },
432         { "check-mailmap", cmd_check_mailmap, RUN_SETUP },
433         { "check-ref-format", cmd_check_ref_format, NO_PARSEOPT  },
434         { "checkout", cmd_checkout, RUN_SETUP | NEED_WORK_TREE },
435         { "checkout-index", cmd_checkout_index,
436                 RUN_SETUP | NEED_WORK_TREE},
437         { "cherry", cmd_cherry, RUN_SETUP },
438         { "cherry-pick", cmd_cherry_pick, RUN_SETUP | NEED_WORK_TREE },
439         { "clean", cmd_clean, RUN_SETUP | NEED_WORK_TREE },
440         { "clone", cmd_clone },
441         { "column", cmd_column, RUN_SETUP_GENTLY },
442         { "commit", cmd_commit, RUN_SETUP | NEED_WORK_TREE },
443         { "commit-tree", cmd_commit_tree, RUN_SETUP | NO_PARSEOPT },
444         { "config", cmd_config, RUN_SETUP_GENTLY | DELAY_PAGER_CONFIG },
445         { "count-objects", cmd_count_objects, RUN_SETUP },
446         { "credential", cmd_credential, RUN_SETUP_GENTLY | NO_PARSEOPT },
447         { "describe", cmd_describe, RUN_SETUP },
448         { "diff", cmd_diff, NO_PARSEOPT },
449         { "diff-files", cmd_diff_files, RUN_SETUP | NEED_WORK_TREE | NO_PARSEOPT },
450         { "diff-index", cmd_diff_index, RUN_SETUP | NO_PARSEOPT },
451         { "diff-tree", cmd_diff_tree, RUN_SETUP | NO_PARSEOPT },
452         { "difftool", cmd_difftool, RUN_SETUP | NEED_WORK_TREE },
453         { "fast-export", cmd_fast_export, RUN_SETUP },
454         { "fetch", cmd_fetch, RUN_SETUP },
455         { "fetch-pack", cmd_fetch_pack, RUN_SETUP | NO_PARSEOPT },
456         { "fmt-merge-msg", cmd_fmt_merge_msg, RUN_SETUP },
457         { "for-each-ref", cmd_for_each_ref, RUN_SETUP },
458         { "format-patch", cmd_format_patch, RUN_SETUP },
459         { "fsck", cmd_fsck, RUN_SETUP },
460         { "fsck-objects", cmd_fsck, RUN_SETUP },
461         { "gc", cmd_gc, RUN_SETUP },
462         { "get-tar-commit-id", cmd_get_tar_commit_id, NO_PARSEOPT },
463         { "grep", cmd_grep, RUN_SETUP_GENTLY },
464         { "hash-object", cmd_hash_object },
465         { "help", cmd_help },
466         { "index-pack", cmd_index_pack, RUN_SETUP_GENTLY | NO_PARSEOPT },
467         { "init", cmd_init_db },
468         { "init-db", cmd_init_db },
469         { "interpret-trailers", cmd_interpret_trailers, RUN_SETUP_GENTLY },
470         { "log", cmd_log, RUN_SETUP },
471         { "ls-files", cmd_ls_files, RUN_SETUP },
472         { "ls-remote", cmd_ls_remote, RUN_SETUP_GENTLY },
473         { "ls-tree", cmd_ls_tree, RUN_SETUP },
474         { "mailinfo", cmd_mailinfo, RUN_SETUP_GENTLY | NO_PARSEOPT },
475         { "mailsplit", cmd_mailsplit, NO_PARSEOPT },
476         { "merge", cmd_merge, RUN_SETUP | NEED_WORK_TREE },
477         { "merge-base", cmd_merge_base, RUN_SETUP },
478         { "merge-file", cmd_merge_file, RUN_SETUP_GENTLY },
479         { "merge-index", cmd_merge_index, RUN_SETUP | NO_PARSEOPT },
480         { "merge-ours", cmd_merge_ours, RUN_SETUP | NO_PARSEOPT },
481         { "merge-recursive", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE | NO_PARSEOPT },
482         { "merge-recursive-ours", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE | NO_PARSEOPT },
483         { "merge-recursive-theirs", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE | NO_PARSEOPT },
484         { "merge-subtree", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE | NO_PARSEOPT },
485         { "merge-tree", cmd_merge_tree, RUN_SETUP | NO_PARSEOPT },
486         { "mktag", cmd_mktag, RUN_SETUP | NO_PARSEOPT },
487         { "mktree", cmd_mktree, RUN_SETUP },
488         { "mv", cmd_mv, RUN_SETUP | NEED_WORK_TREE },
489         { "name-rev", cmd_name_rev, RUN_SETUP },
490         { "notes", cmd_notes, RUN_SETUP },
491         { "pack-objects", cmd_pack_objects, RUN_SETUP },
492         { "pack-redundant", cmd_pack_redundant, RUN_SETUP | NO_PARSEOPT },
493         { "pack-refs", cmd_pack_refs, RUN_SETUP },
494         { "patch-id", cmd_patch_id, RUN_SETUP_GENTLY | NO_PARSEOPT },
495         { "pickaxe", cmd_blame, RUN_SETUP },
496         { "prune", cmd_prune, RUN_SETUP },
497         { "prune-packed", cmd_prune_packed, RUN_SETUP },
498         { "pull", cmd_pull, RUN_SETUP | NEED_WORK_TREE },
499         { "push", cmd_push, RUN_SETUP },
500         { "read-tree", cmd_read_tree, RUN_SETUP | SUPPORT_SUPER_PREFIX},
501         { "rebase--helper", cmd_rebase__helper, RUN_SETUP | NEED_WORK_TREE },
502         { "receive-pack", cmd_receive_pack },
503         { "reflog", cmd_reflog, RUN_SETUP },
504         { "remote", cmd_remote, RUN_SETUP },
505         { "remote-ext", cmd_remote_ext, NO_PARSEOPT },
506         { "remote-fd", cmd_remote_fd, NO_PARSEOPT },
507         { "repack", cmd_repack, RUN_SETUP },
508         { "replace", cmd_replace, RUN_SETUP },
509         { "rerere", cmd_rerere, RUN_SETUP },
510         { "reset", cmd_reset, RUN_SETUP },
511         { "rev-list", cmd_rev_list, RUN_SETUP | NO_PARSEOPT },
512         { "rev-parse", cmd_rev_parse, NO_PARSEOPT },
513         { "revert", cmd_revert, RUN_SETUP | NEED_WORK_TREE },
514         { "rm", cmd_rm, RUN_SETUP },
515         { "send-pack", cmd_send_pack, RUN_SETUP },
516         { "shortlog", cmd_shortlog, RUN_SETUP_GENTLY | USE_PAGER },
517         { "show", cmd_show, RUN_SETUP },
518         { "show-branch", cmd_show_branch, RUN_SETUP },
519         { "show-ref", cmd_show_ref, RUN_SETUP },
520         { "stage", cmd_add, RUN_SETUP | NEED_WORK_TREE },
521         { "status", cmd_status, RUN_SETUP | NEED_WORK_TREE },
522         { "stripspace", cmd_stripspace },
523         { "submodule--helper", cmd_submodule__helper, RUN_SETUP | SUPPORT_SUPER_PREFIX | NO_PARSEOPT },
524         { "symbolic-ref", cmd_symbolic_ref, RUN_SETUP },
525         { "tag", cmd_tag, RUN_SETUP | DELAY_PAGER_CONFIG },
526         { "unpack-file", cmd_unpack_file, RUN_SETUP | NO_PARSEOPT },
527         { "unpack-objects", cmd_unpack_objects, RUN_SETUP | NO_PARSEOPT },
528         { "update-index", cmd_update_index, RUN_SETUP },
529         { "update-ref", cmd_update_ref, RUN_SETUP },
530         { "update-server-info", cmd_update_server_info, RUN_SETUP },
531         { "upload-archive", cmd_upload_archive, NO_PARSEOPT },
532         { "upload-archive--writer", cmd_upload_archive_writer, NO_PARSEOPT },
533         { "var", cmd_var, RUN_SETUP_GENTLY | NO_PARSEOPT },
534         { "verify-commit", cmd_verify_commit, RUN_SETUP },
535         { "verify-pack", cmd_verify_pack },
536         { "verify-tag", cmd_verify_tag, RUN_SETUP },
537         { "version", cmd_version },
538         { "whatchanged", cmd_whatchanged, RUN_SETUP },
539         { "worktree", cmd_worktree, RUN_SETUP | NO_PARSEOPT },
540         { "write-tree", cmd_write_tree, RUN_SETUP },
541 };
542
543 static struct cmd_struct *get_builtin(const char *s)
544 {
545         int i;
546         for (i = 0; i < ARRAY_SIZE(commands); i++) {
547                 struct cmd_struct *p = commands + i;
548                 if (!strcmp(s, p->cmd))
549                         return p;
550         }
551         return NULL;
552 }
553
554 int is_builtin(const char *s)
555 {
556         return !!get_builtin(s);
557 }
558
559 static void list_builtins(struct string_list *out, unsigned int exclude_option)
560 {
561         int i;
562         for (i = 0; i < ARRAY_SIZE(commands); i++) {
563                 if (exclude_option &&
564                     (commands[i].option & exclude_option))
565                         continue;
566                 string_list_append(out, commands[i].cmd);
567         }
568 }
569
570 #ifdef STRIP_EXTENSION
571 static void strip_extension(const char **argv)
572 {
573         size_t len;
574
575         if (strip_suffix(argv[0], STRIP_EXTENSION, &len))
576                 argv[0] = xmemdupz(argv[0], len);
577 }
578 #else
579 #define strip_extension(cmd)
580 #endif
581
582 static void handle_builtin(int argc, const char **argv)
583 {
584         struct argv_array args = ARGV_ARRAY_INIT;
585         const char *cmd;
586         struct cmd_struct *builtin;
587
588         strip_extension(argv);
589         cmd = argv[0];
590
591         /* Turn "git cmd --help" into "git help --exclude-guides cmd" */
592         if (argc > 1 && !strcmp(argv[1], "--help")) {
593                 int i;
594
595                 argv[1] = argv[0];
596                 argv[0] = cmd = "help";
597
598                 for (i = 0; i < argc; i++) {
599                         argv_array_push(&args, argv[i]);
600                         if (!i)
601                                 argv_array_push(&args, "--exclude-guides");
602                 }
603
604                 argc++;
605                 argv = args.argv;
606         }
607
608         builtin = get_builtin(cmd);
609         if (builtin)
610                 exit(run_builtin(builtin, argc, argv));
611         argv_array_clear(&args);
612 }
613
614 static void execv_dashed_external(const char **argv)
615 {
616         struct child_process cmd = CHILD_PROCESS_INIT;
617         int status;
618
619         if (get_super_prefix())
620                 die("%s doesn't support --super-prefix", argv[0]);
621
622         if (use_pager == -1 && !is_builtin(argv[0]))
623                 use_pager = check_pager_config(argv[0]);
624         commit_pager_choice();
625
626         argv_array_pushf(&cmd.args, "git-%s", argv[0]);
627         argv_array_pushv(&cmd.args, argv + 1);
628         cmd.clean_on_exit = 1;
629         cmd.wait_after_clean = 1;
630         cmd.silent_exec_failure = 1;
631
632         trace_argv_printf(cmd.args.argv, "trace: exec:");
633
634         /*
635          * If we fail because the command is not found, it is
636          * OK to return. Otherwise, we just pass along the status code,
637          * or our usual generic code if we were not even able to exec
638          * the program.
639          */
640         status = run_command(&cmd);
641         if (status >= 0)
642                 exit(status);
643         else if (errno != ENOENT)
644                 exit(128);
645 }
646
647 static int run_argv(int *argcp, const char ***argv)
648 {
649         int done_alias = 0;
650
651         while (1) {
652                 /*
653                  * If we tried alias and futzed with our environment,
654                  * it no longer is safe to invoke builtins directly in
655                  * general.  We have to spawn them as dashed externals.
656                  *
657                  * NEEDSWORK: if we can figure out cases
658                  * where it is safe to do, we can avoid spawning a new
659                  * process.
660                  */
661                 if (!done_alias)
662                         handle_builtin(*argcp, *argv);
663
664                 /* .. then try the external ones */
665                 execv_dashed_external(*argv);
666
667                 /* It could be an alias -- this works around the insanity
668                  * of overriding "git log" with "git show" by having
669                  * alias.log = show
670                  */
671                 if (done_alias)
672                         break;
673                 if (!handle_alias(argcp, argv))
674                         break;
675                 done_alias = 1;
676         }
677
678         return done_alias;
679 }
680
681 int cmd_main(int argc, const char **argv)
682 {
683         const char *cmd;
684         int done_help = 0;
685
686         cmd = argv[0];
687         if (!cmd)
688                 cmd = "git-help";
689         else {
690                 const char *slash = find_last_dir_sep(cmd);
691                 if (slash)
692                         cmd = slash + 1;
693         }
694
695         trace_command_performance(argv);
696
697         /*
698          * "git-xxxx" is the same as "git xxxx", but we obviously:
699          *
700          *  - cannot take flags in between the "git" and the "xxxx".
701          *  - cannot execute it externally (since it would just do
702          *    the same thing over again)
703          *
704          * So we just directly call the builtin handler, and die if
705          * that one cannot handle it.
706          */
707         if (skip_prefix(cmd, "git-", &cmd)) {
708                 argv[0] = cmd;
709                 handle_builtin(argc, argv);
710                 die("cannot handle %s as a builtin", cmd);
711         }
712
713         /* Look for flags.. */
714         argv++;
715         argc--;
716         handle_options(&argv, &argc, NULL);
717         if (argc > 0) {
718                 /* translate --help and --version into commands */
719                 skip_prefix(argv[0], "--", &argv[0]);
720         } else {
721                 /* The user didn't specify a command; give them help */
722                 commit_pager_choice();
723                 printf("usage: %s\n\n", git_usage_string);
724                 list_common_cmds_help();
725                 printf("\n%s\n", _(git_more_info_string));
726                 exit(1);
727         }
728         cmd = argv[0];
729
730         /*
731          * We use PATH to find git commands, but we prepend some higher
732          * precedence paths: the "--exec-path" option, the GIT_EXEC_PATH
733          * environment, and the $(gitexecdir) from the Makefile at build
734          * time.
735          */
736         setup_path();
737
738         while (1) {
739                 int was_alias = run_argv(&argc, &argv);
740                 if (errno != ENOENT)
741                         break;
742                 if (was_alias) {
743                         fprintf(stderr, _("expansion of alias '%s' failed; "
744                                           "'%s' is not a git command\n"),
745                                 cmd, argv[0]);
746                         exit(1);
747                 }
748                 if (!done_help) {
749                         cmd = argv[0] = help_unknown_cmd(cmd);
750                         done_help = 1;
751                 } else
752                         break;
753         }
754
755         fprintf(stderr, _("failed to run command '%s': %s\n"),
756                 cmd, strerror(errno));
757
758         return 1;
759 }