Merge branch 'jk/shortlog'
[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 struct startup_info git_startup_info;
19 static int use_pager = -1;
20 static char *orig_cwd;
21 static const char *env_names[] = {
22         GIT_DIR_ENVIRONMENT,
23         GIT_WORK_TREE_ENVIRONMENT,
24         GIT_IMPLICIT_WORK_TREE_ENVIRONMENT,
25         GIT_PREFIX_ENVIRONMENT
26 };
27 static char *orig_env[4];
28 static int saved_env_before_alias;
29
30 static void save_env_before_alias(void)
31 {
32         int i;
33         if (saved_env_before_alias)
34                 return;
35         saved_env_before_alias = 1;
36         orig_cwd = xgetcwd();
37         for (i = 0; i < ARRAY_SIZE(env_names); i++) {
38                 orig_env[i] = getenv(env_names[i]);
39                 if (orig_env[i])
40                         orig_env[i] = xstrdup(orig_env[i]);
41         }
42 }
43
44 static void restore_env(int external_alias)
45 {
46         int i;
47         if (!external_alias && orig_cwd && chdir(orig_cwd))
48                 die_errno("could not move to %s", orig_cwd);
49         free(orig_cwd);
50         for (i = 0; i < ARRAY_SIZE(env_names); i++) {
51                 if (external_alias &&
52                     !strcmp(env_names[i], GIT_PREFIX_ENVIRONMENT))
53                         continue;
54                 if (orig_env[i])
55                         setenv(env_names[i], orig_env[i], 1);
56                 else
57                         unsetenv(env_names[i]);
58         }
59 }
60
61 static void commit_pager_choice(void) {
62         switch (use_pager) {
63         case 0:
64                 setenv("GIT_PAGER", "cat", 1);
65                 break;
66         case 1:
67                 setup_pager();
68                 break;
69         default:
70                 break;
71         }
72 }
73
74 static int handle_options(const char ***argv, int *argc, int *envchanged)
75 {
76         const char **orig_argv = *argv;
77
78         while (*argc > 0) {
79                 const char *cmd = (*argv)[0];
80                 if (cmd[0] != '-')
81                         break;
82
83                 /*
84                  * For legacy reasons, the "version" and "help"
85                  * commands can be written with "--" prepended
86                  * to make them look like flags.
87                  */
88                 if (!strcmp(cmd, "--help") || !strcmp(cmd, "--version"))
89                         break;
90
91                 /*
92                  * Check remaining flags.
93                  */
94                 if (skip_prefix(cmd, "--exec-path", &cmd)) {
95                         if (*cmd == '=')
96                                 git_set_argv_exec_path(cmd + 1);
97                         else {
98                                 puts(git_exec_path());
99                                 exit(0);
100                         }
101                 } else if (!strcmp(cmd, "--html-path")) {
102                         puts(system_path(GIT_HTML_PATH));
103                         exit(0);
104                 } else if (!strcmp(cmd, "--man-path")) {
105                         puts(system_path(GIT_MAN_PATH));
106                         exit(0);
107                 } else if (!strcmp(cmd, "--info-path")) {
108                         puts(system_path(GIT_INFO_PATH));
109                         exit(0);
110                 } else if (!strcmp(cmd, "-p") || !strcmp(cmd, "--paginate")) {
111                         use_pager = 1;
112                 } else if (!strcmp(cmd, "--no-pager")) {
113                         use_pager = 0;
114                         if (envchanged)
115                                 *envchanged = 1;
116                 } else if (!strcmp(cmd, "--no-replace-objects")) {
117                         check_replace_refs = 0;
118                         setenv(NO_REPLACE_OBJECTS_ENVIRONMENT, "1", 1);
119                         if (envchanged)
120                                 *envchanged = 1;
121                 } else if (!strcmp(cmd, "--git-dir")) {
122                         if (*argc < 2) {
123                                 fprintf(stderr, "No directory given for --git-dir.\n" );
124                                 usage(git_usage_string);
125                         }
126                         setenv(GIT_DIR_ENVIRONMENT, (*argv)[1], 1);
127                         if (envchanged)
128                                 *envchanged = 1;
129                         (*argv)++;
130                         (*argc)--;
131                 } else if (skip_prefix(cmd, "--git-dir=", &cmd)) {
132                         setenv(GIT_DIR_ENVIRONMENT, cmd, 1);
133                         if (envchanged)
134                                 *envchanged = 1;
135                 } else if (!strcmp(cmd, "--namespace")) {
136                         if (*argc < 2) {
137                                 fprintf(stderr, "No namespace given for --namespace.\n" );
138                                 usage(git_usage_string);
139                         }
140                         setenv(GIT_NAMESPACE_ENVIRONMENT, (*argv)[1], 1);
141                         if (envchanged)
142                                 *envchanged = 1;
143                         (*argv)++;
144                         (*argc)--;
145                 } else if (skip_prefix(cmd, "--namespace=", &cmd)) {
146                         setenv(GIT_NAMESPACE_ENVIRONMENT, cmd, 1);
147                         if (envchanged)
148                                 *envchanged = 1;
149                 } else if (!strcmp(cmd, "--work-tree")) {
150                         if (*argc < 2) {
151                                 fprintf(stderr, "No directory given for --work-tree.\n" );
152                                 usage(git_usage_string);
153                         }
154                         setenv(GIT_WORK_TREE_ENVIRONMENT, (*argv)[1], 1);
155                         if (envchanged)
156                                 *envchanged = 1;
157                         (*argv)++;
158                         (*argc)--;
159                 } else if (skip_prefix(cmd, "--work-tree=", &cmd)) {
160                         setenv(GIT_WORK_TREE_ENVIRONMENT, cmd, 1);
161                         if (envchanged)
162                                 *envchanged = 1;
163                 } else if (!strcmp(cmd, "--bare")) {
164                         char *cwd = xgetcwd();
165                         is_bare_repository_cfg = 1;
166                         setenv(GIT_DIR_ENVIRONMENT, cwd, 0);
167                         free(cwd);
168                         setenv(GIT_IMPLICIT_WORK_TREE_ENVIRONMENT, "0", 1);
169                         if (envchanged)
170                                 *envchanged = 1;
171                 } else if (!strcmp(cmd, "-c")) {
172                         if (*argc < 2) {
173                                 fprintf(stderr, "-c expects a configuration string\n" );
174                                 usage(git_usage_string);
175                         }
176                         git_config_push_parameter((*argv)[1]);
177                         (*argv)++;
178                         (*argc)--;
179                 } else if (!strcmp(cmd, "--literal-pathspecs")) {
180                         setenv(GIT_LITERAL_PATHSPECS_ENVIRONMENT, "1", 1);
181                         if (envchanged)
182                                 *envchanged = 1;
183                 } else if (!strcmp(cmd, "--no-literal-pathspecs")) {
184                         setenv(GIT_LITERAL_PATHSPECS_ENVIRONMENT, "0", 1);
185                         if (envchanged)
186                                 *envchanged = 1;
187                 } else if (!strcmp(cmd, "--glob-pathspecs")) {
188                         setenv(GIT_GLOB_PATHSPECS_ENVIRONMENT, "1", 1);
189                         if (envchanged)
190                                 *envchanged = 1;
191                 } else if (!strcmp(cmd, "--noglob-pathspecs")) {
192                         setenv(GIT_NOGLOB_PATHSPECS_ENVIRONMENT, "1", 1);
193                         if (envchanged)
194                                 *envchanged = 1;
195                 } else if (!strcmp(cmd, "--icase-pathspecs")) {
196                         setenv(GIT_ICASE_PATHSPECS_ENVIRONMENT, "1", 1);
197                         if (envchanged)
198                                 *envchanged = 1;
199                 } else if (!strcmp(cmd, "--shallow-file")) {
200                         (*argv)++;
201                         (*argc)--;
202                         set_alternate_shallow_file((*argv)[0], 1);
203                         if (envchanged)
204                                 *envchanged = 1;
205                 } else if (!strcmp(cmd, "-C")) {
206                         if (*argc < 2) {
207                                 fprintf(stderr, "No directory given for -C.\n" );
208                                 usage(git_usage_string);
209                         }
210                         if ((*argv)[1][0]) {
211                                 if (chdir((*argv)[1]))
212                                         die_errno("Cannot change to '%s'", (*argv)[1]);
213                                 if (envchanged)
214                                         *envchanged = 1;
215                         }
216                         (*argv)++;
217                         (*argc)--;
218                 } else {
219                         fprintf(stderr, "Unknown option: %s\n", cmd);
220                         usage(git_usage_string);
221                 }
222
223                 (*argv)++;
224                 (*argc)--;
225         }
226         return (*argv) - orig_argv;
227 }
228
229 static int handle_alias(int *argcp, const char ***argv)
230 {
231         int envchanged = 0, ret = 0, saved_errno = errno;
232         int count, option_count;
233         const char **new_argv;
234         const char *alias_command;
235         char *alias_string;
236         int unused_nongit;
237
238         save_env_before_alias();
239         setup_git_directory_gently(&unused_nongit);
240
241         alias_command = (*argv)[0];
242         alias_string = alias_lookup(alias_command);
243         if (alias_string) {
244                 if (alias_string[0] == '!') {
245                         const char **alias_argv;
246                         int argc = *argcp, i;
247
248                         commit_pager_choice();
249                         restore_env(1);
250
251                         /* build alias_argv */
252                         alias_argv = xmalloc(sizeof(*alias_argv) * (argc + 1));
253                         alias_argv[0] = alias_string + 1;
254                         for (i = 1; i < argc; ++i)
255                                 alias_argv[i] = (*argv)[i];
256                         alias_argv[argc] = NULL;
257
258                         ret = run_command_v_opt(alias_argv, RUN_USING_SHELL);
259                         if (ret >= 0)   /* normal exit */
260                                 exit(ret);
261
262                         die_errno("While expanding alias '%s': '%s'",
263                             alias_command, alias_string + 1);
264                 }
265                 count = split_cmdline(alias_string, &new_argv);
266                 if (count < 0)
267                         die("Bad alias.%s string: %s", alias_command,
268                             split_cmdline_strerror(count));
269                 option_count = handle_options(&new_argv, &count, &envchanged);
270                 if (envchanged)
271                         die("alias '%s' changes environment variables\n"
272                                  "You can use '!git' in the alias to do this.",
273                                  alias_command);
274                 memmove(new_argv - option_count, new_argv,
275                                 count * sizeof(char *));
276                 new_argv -= option_count;
277
278                 if (count < 1)
279                         die("empty alias for %s", alias_command);
280
281                 if (!strcmp(alias_command, new_argv[0]))
282                         die("recursive alias: %s", alias_command);
283
284                 trace_argv_printf(new_argv,
285                                   "trace: alias expansion: %s =>",
286                                   alias_command);
287
288                 REALLOC_ARRAY(new_argv, count + *argcp);
289                 /* insert after command name */
290                 memcpy(new_argv + count, *argv + 1, sizeof(char *) * *argcp);
291
292                 *argv = new_argv;
293                 *argcp += count - 1;
294
295                 ret = 1;
296         }
297
298         restore_env(0);
299
300         errno = saved_errno;
301
302         return ret;
303 }
304
305 #define RUN_SETUP               (1<<0)
306 #define RUN_SETUP_GENTLY        (1<<1)
307 #define USE_PAGER               (1<<2)
308 /*
309  * require working tree to be present -- anything uses this needs
310  * RUN_SETUP for reading from the configuration file.
311  */
312 #define NEED_WORK_TREE          (1<<3)
313
314 struct cmd_struct {
315         const char *cmd;
316         int (*fn)(int, const char **, const char *);
317         int option;
318 };
319
320 static int run_builtin(struct cmd_struct *p, int argc, const char **argv)
321 {
322         int status, help;
323         struct stat st;
324         const char *prefix;
325
326         prefix = NULL;
327         help = argc == 2 && !strcmp(argv[1], "-h");
328         if (!help) {
329                 if (p->option & RUN_SETUP)
330                         prefix = setup_git_directory();
331                 else if (p->option & RUN_SETUP_GENTLY) {
332                         int nongit_ok;
333                         prefix = setup_git_directory_gently(&nongit_ok);
334                 }
335
336                 if (use_pager == -1 && p->option & (RUN_SETUP | RUN_SETUP_GENTLY))
337                         use_pager = check_pager_config(p->cmd);
338                 if (use_pager == -1 && p->option & USE_PAGER)
339                         use_pager = 1;
340
341                 if ((p->option & (RUN_SETUP | RUN_SETUP_GENTLY)) &&
342                     startup_info->have_repository) /* get_git_dir() may set up repo, avoid that */
343                         trace_repo_setup(prefix);
344         }
345         commit_pager_choice();
346
347         if (!help && p->option & NEED_WORK_TREE)
348                 setup_work_tree();
349
350         trace_argv_printf(argv, "trace: built-in: git");
351
352         status = p->fn(argc, argv, prefix);
353         if (status)
354                 return status;
355
356         /* Somebody closed stdout? */
357         if (fstat(fileno(stdout), &st))
358                 return 0;
359         /* Ignore write errors for pipes and sockets.. */
360         if (S_ISFIFO(st.st_mode) || S_ISSOCK(st.st_mode))
361                 return 0;
362
363         /* Check for ENOSPC and EIO errors.. */
364         if (fflush(stdout))
365                 die_errno("write failure on standard output");
366         if (ferror(stdout))
367                 die("unknown write failure on standard output");
368         if (fclose(stdout))
369                 die_errno("close failed on standard output");
370         return 0;
371 }
372
373 static struct cmd_struct commands[] = {
374         { "add", cmd_add, RUN_SETUP | NEED_WORK_TREE },
375         { "am", cmd_am, RUN_SETUP | NEED_WORK_TREE },
376         { "annotate", cmd_annotate, RUN_SETUP },
377         { "apply", cmd_apply, RUN_SETUP_GENTLY },
378         { "archive", cmd_archive },
379         { "bisect--helper", cmd_bisect__helper, RUN_SETUP },
380         { "blame", cmd_blame, RUN_SETUP },
381         { "branch", cmd_branch, RUN_SETUP },
382         { "bundle", cmd_bundle, RUN_SETUP_GENTLY },
383         { "cat-file", cmd_cat_file, RUN_SETUP },
384         { "check-attr", cmd_check_attr, RUN_SETUP },
385         { "check-ignore", cmd_check_ignore, RUN_SETUP | NEED_WORK_TREE },
386         { "check-mailmap", cmd_check_mailmap, RUN_SETUP },
387         { "check-ref-format", cmd_check_ref_format },
388         { "checkout", cmd_checkout, RUN_SETUP | NEED_WORK_TREE },
389         { "checkout-index", cmd_checkout_index,
390                 RUN_SETUP | NEED_WORK_TREE},
391         { "cherry", cmd_cherry, RUN_SETUP },
392         { "cherry-pick", cmd_cherry_pick, RUN_SETUP | NEED_WORK_TREE },
393         { "clean", cmd_clean, RUN_SETUP | NEED_WORK_TREE },
394         { "clone", cmd_clone },
395         { "column", cmd_column, RUN_SETUP_GENTLY },
396         { "commit", cmd_commit, RUN_SETUP | NEED_WORK_TREE },
397         { "commit-tree", cmd_commit_tree, RUN_SETUP },
398         { "config", cmd_config, RUN_SETUP_GENTLY },
399         { "count-objects", cmd_count_objects, RUN_SETUP },
400         { "credential", cmd_credential, RUN_SETUP_GENTLY },
401         { "describe", cmd_describe, RUN_SETUP },
402         { "diff", cmd_diff },
403         { "diff-files", cmd_diff_files, RUN_SETUP | NEED_WORK_TREE },
404         { "diff-index", cmd_diff_index, RUN_SETUP },
405         { "diff-tree", cmd_diff_tree, RUN_SETUP },
406         { "fast-export", cmd_fast_export, RUN_SETUP },
407         { "fetch", cmd_fetch, RUN_SETUP },
408         { "fetch-pack", cmd_fetch_pack, RUN_SETUP },
409         { "fmt-merge-msg", cmd_fmt_merge_msg, RUN_SETUP },
410         { "for-each-ref", cmd_for_each_ref, RUN_SETUP },
411         { "format-patch", cmd_format_patch, RUN_SETUP },
412         { "fsck", cmd_fsck, RUN_SETUP },
413         { "fsck-objects", cmd_fsck, RUN_SETUP },
414         { "gc", cmd_gc, RUN_SETUP },
415         { "get-tar-commit-id", cmd_get_tar_commit_id },
416         { "grep", cmd_grep, RUN_SETUP_GENTLY },
417         { "hash-object", cmd_hash_object },
418         { "help", cmd_help },
419         { "index-pack", cmd_index_pack, RUN_SETUP_GENTLY },
420         { "init", cmd_init_db },
421         { "init-db", cmd_init_db },
422         { "interpret-trailers", cmd_interpret_trailers, RUN_SETUP_GENTLY },
423         { "log", cmd_log, RUN_SETUP },
424         { "ls-files", cmd_ls_files, RUN_SETUP },
425         { "ls-remote", cmd_ls_remote, RUN_SETUP_GENTLY },
426         { "ls-tree", cmd_ls_tree, RUN_SETUP },
427         { "mailinfo", cmd_mailinfo },
428         { "mailsplit", cmd_mailsplit },
429         { "merge", cmd_merge, RUN_SETUP | NEED_WORK_TREE },
430         { "merge-base", cmd_merge_base, RUN_SETUP },
431         { "merge-file", cmd_merge_file, RUN_SETUP_GENTLY },
432         { "merge-index", cmd_merge_index, RUN_SETUP },
433         { "merge-ours", cmd_merge_ours, RUN_SETUP },
434         { "merge-recursive", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE },
435         { "merge-recursive-ours", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE },
436         { "merge-recursive-theirs", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE },
437         { "merge-subtree", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE },
438         { "merge-tree", cmd_merge_tree, RUN_SETUP },
439         { "mktag", cmd_mktag, RUN_SETUP },
440         { "mktree", cmd_mktree, RUN_SETUP },
441         { "mv", cmd_mv, RUN_SETUP | NEED_WORK_TREE },
442         { "name-rev", cmd_name_rev, RUN_SETUP },
443         { "notes", cmd_notes, RUN_SETUP },
444         { "pack-objects", cmd_pack_objects, RUN_SETUP },
445         { "pack-redundant", cmd_pack_redundant, RUN_SETUP },
446         { "pack-refs", cmd_pack_refs, RUN_SETUP },
447         { "patch-id", cmd_patch_id },
448         { "pickaxe", cmd_blame, RUN_SETUP },
449         { "prune", cmd_prune, RUN_SETUP },
450         { "prune-packed", cmd_prune_packed, RUN_SETUP },
451         { "pull", cmd_pull, RUN_SETUP | NEED_WORK_TREE },
452         { "push", cmd_push, RUN_SETUP },
453         { "read-tree", cmd_read_tree, RUN_SETUP },
454         { "receive-pack", cmd_receive_pack },
455         { "reflog", cmd_reflog, RUN_SETUP },
456         { "remote", cmd_remote, RUN_SETUP },
457         { "remote-ext", cmd_remote_ext },
458         { "remote-fd", cmd_remote_fd },
459         { "repack", cmd_repack, RUN_SETUP },
460         { "replace", cmd_replace, RUN_SETUP },
461         { "rerere", cmd_rerere, RUN_SETUP },
462         { "reset", cmd_reset, RUN_SETUP },
463         { "rev-list", cmd_rev_list, RUN_SETUP },
464         { "rev-parse", cmd_rev_parse },
465         { "revert", cmd_revert, RUN_SETUP | NEED_WORK_TREE },
466         { "rm", cmd_rm, RUN_SETUP },
467         { "send-pack", cmd_send_pack, RUN_SETUP },
468         { "shortlog", cmd_shortlog, RUN_SETUP_GENTLY | USE_PAGER },
469         { "show", cmd_show, RUN_SETUP },
470         { "show-branch", cmd_show_branch, RUN_SETUP },
471         { "show-ref", cmd_show_ref, RUN_SETUP },
472         { "stage", cmd_add, RUN_SETUP | NEED_WORK_TREE },
473         { "status", cmd_status, RUN_SETUP | NEED_WORK_TREE },
474         { "stripspace", cmd_stripspace },
475         { "submodule--helper", cmd_submodule__helper, RUN_SETUP },
476         { "symbolic-ref", cmd_symbolic_ref, RUN_SETUP },
477         { "tag", cmd_tag, RUN_SETUP },
478         { "unpack-file", cmd_unpack_file, RUN_SETUP },
479         { "unpack-objects", cmd_unpack_objects, RUN_SETUP },
480         { "update-index", cmd_update_index, RUN_SETUP },
481         { "update-ref", cmd_update_ref, RUN_SETUP },
482         { "update-server-info", cmd_update_server_info, RUN_SETUP },
483         { "upload-archive", cmd_upload_archive },
484         { "upload-archive--writer", cmd_upload_archive_writer },
485         { "var", cmd_var, RUN_SETUP_GENTLY },
486         { "verify-commit", cmd_verify_commit, RUN_SETUP },
487         { "verify-pack", cmd_verify_pack },
488         { "verify-tag", cmd_verify_tag, RUN_SETUP },
489         { "version", cmd_version },
490         { "whatchanged", cmd_whatchanged, RUN_SETUP },
491         { "worktree", cmd_worktree, RUN_SETUP },
492         { "write-tree", cmd_write_tree, RUN_SETUP },
493 };
494
495 static struct cmd_struct *get_builtin(const char *s)
496 {
497         int i;
498         for (i = 0; i < ARRAY_SIZE(commands); i++) {
499                 struct cmd_struct *p = commands + i;
500                 if (!strcmp(s, p->cmd))
501                         return p;
502         }
503         return NULL;
504 }
505
506 int is_builtin(const char *s)
507 {
508         return !!get_builtin(s);
509 }
510
511 static void handle_builtin(int argc, const char **argv)
512 {
513         const char *cmd = argv[0];
514         int i;
515         static const char ext[] = STRIP_EXTENSION;
516         struct cmd_struct *builtin;
517
518         if (sizeof(ext) > 1) {
519                 i = strlen(argv[0]) - strlen(ext);
520                 if (i > 0 && !strcmp(argv[0] + i, ext)) {
521                         char *argv0 = xstrdup(argv[0]);
522                         argv[0] = cmd = argv0;
523                         argv0[i] = '\0';
524                 }
525         }
526
527         /* Turn "git cmd --help" into "git help cmd" */
528         if (argc > 1 && !strcmp(argv[1], "--help")) {
529                 argv[1] = argv[0];
530                 argv[0] = cmd = "help";
531         }
532
533         builtin = get_builtin(cmd);
534         if (builtin) {
535                 /*
536                  * XXX: if we can figure out cases where it is _safe_
537                  * to do, we can avoid spawning a new process when
538                  * saved_env_before_alias is true
539                  * (i.e. setup_git_dir* has been run once)
540                  */
541                 if (!saved_env_before_alias)
542                         exit(run_builtin(builtin, argc, argv));
543         }
544 }
545
546 static void execv_dashed_external(const char **argv)
547 {
548         struct strbuf cmd = STRBUF_INIT;
549         const char *tmp;
550         int status;
551
552         if (use_pager == -1)
553                 use_pager = check_pager_config(argv[0]);
554         commit_pager_choice();
555
556         strbuf_addf(&cmd, "git-%s", argv[0]);
557
558         /*
559          * argv[0] must be the git command, but the argv array
560          * belongs to the caller, and may be reused in
561          * subsequent loop iterations. Save argv[0] and
562          * restore it on error.
563          */
564         tmp = argv[0];
565         argv[0] = cmd.buf;
566
567         trace_argv_printf(argv, "trace: exec:");
568
569         /*
570          * if we fail because the command is not found, it is
571          * OK to return. Otherwise, we just pass along the status code.
572          */
573         status = run_command_v_opt(argv, RUN_SILENT_EXEC_FAILURE | RUN_CLEAN_ON_EXIT);
574         if (status >= 0 || errno != ENOENT)
575                 exit(status);
576
577         argv[0] = tmp;
578
579         strbuf_release(&cmd);
580 }
581
582 static int run_argv(int *argcp, const char ***argv)
583 {
584         int done_alias = 0;
585
586         while (1) {
587                 /* See if it's a builtin */
588                 handle_builtin(*argcp, *argv);
589
590                 /* .. then try the external ones */
591                 execv_dashed_external(*argv);
592
593                 /* It could be an alias -- this works around the insanity
594                  * of overriding "git log" with "git show" by having
595                  * alias.log = show
596                  */
597                 if (done_alias)
598                         break;
599                 if (!handle_alias(argcp, argv))
600                         break;
601                 done_alias = 1;
602         }
603
604         return done_alias;
605 }
606
607 /*
608  * Many parts of Git have subprograms communicate via pipe, expect the
609  * upstream of a pipe to die with SIGPIPE when the downstream of a
610  * pipe does not need to read all that is written.  Some third-party
611  * programs that ignore or block SIGPIPE for their own reason forget
612  * to restore SIGPIPE handling to the default before spawning Git and
613  * break this carefully orchestrated machinery.
614  *
615  * Restore the way SIGPIPE is handled to default, which is what we
616  * expect.
617  */
618 static void restore_sigpipe_to_default(void)
619 {
620         sigset_t unblock;
621
622         sigemptyset(&unblock);
623         sigaddset(&unblock, SIGPIPE);
624         sigprocmask(SIG_UNBLOCK, &unblock, NULL);
625         signal(SIGPIPE, SIG_DFL);
626 }
627
628 int main(int argc, char **av)
629 {
630         const char **argv = (const char **) av;
631         const char *cmd;
632         int done_help = 0;
633
634         startup_info = &git_startup_info;
635
636         cmd = git_extract_argv0_path(argv[0]);
637         if (!cmd)
638                 cmd = "git-help";
639
640         /*
641          * Always open file descriptors 0/1/2 to avoid clobbering files
642          * in die().  It also avoids messing up when the pipes are dup'ed
643          * onto stdin/stdout/stderr in the child processes we spawn.
644          */
645         sanitize_stdfds();
646
647         restore_sigpipe_to_default();
648
649         git_setup_gettext();
650
651         trace_command_performance(argv);
652
653         /*
654          * "git-xxxx" is the same as "git xxxx", but we obviously:
655          *
656          *  - cannot take flags in between the "git" and the "xxxx".
657          *  - cannot execute it externally (since it would just do
658          *    the same thing over again)
659          *
660          * So we just directly call the builtin handler, and die if
661          * that one cannot handle it.
662          */
663         if (skip_prefix(cmd, "git-", &cmd)) {
664                 argv[0] = cmd;
665                 handle_builtin(argc, argv);
666                 die("cannot handle %s as a builtin", cmd);
667         }
668
669         /* Look for flags.. */
670         argv++;
671         argc--;
672         handle_options(&argv, &argc, NULL);
673         if (argc > 0) {
674                 /* translate --help and --version into commands */
675                 skip_prefix(argv[0], "--", &argv[0]);
676         } else {
677                 /* The user didn't specify a command; give them help */
678                 commit_pager_choice();
679                 printf("usage: %s\n\n", git_usage_string);
680                 list_common_cmds_help();
681                 printf("\n%s\n", _(git_more_info_string));
682                 exit(1);
683         }
684         cmd = argv[0];
685
686         /*
687          * We use PATH to find git commands, but we prepend some higher
688          * precedence paths: the "--exec-path" option, the GIT_EXEC_PATH
689          * environment, and the $(gitexecdir) from the Makefile at build
690          * time.
691          */
692         setup_path();
693
694         while (1) {
695                 int was_alias = run_argv(&argc, &argv);
696                 if (errno != ENOENT)
697                         break;
698                 if (was_alias) {
699                         fprintf(stderr, "Expansion of alias '%s' failed; "
700                                 "'%s' is not a git command\n",
701                                 cmd, argv[0]);
702                         exit(1);
703                 }
704                 if (!done_help) {
705                         cmd = argv[0] = help_unknown_cmd(cmd);
706                         done_help = 1;
707                 } else
708                         break;
709         }
710
711         fprintf(stderr, "Failed to run command '%s': %s\n",
712                 cmd, strerror(errno));
713
714         return 1;
715 }