Merge branch 'nd/files-backend-git-dir' into next
[git] / 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, "--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
246 static 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
328 struct cmd_struct {
329         const char *cmd;
330         int (*fn)(int, const char **, const char *);
331         int option;
332 };
333
334 static 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
392 static 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
516 static 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
527 int is_builtin(const char *s)
528 {
529         return !!get_builtin(s);
530 }
531
532 #ifdef STRIP_EXTENSION
533 static 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
544 static 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
576 static 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
609 static 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
643 int 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 }