Merge branch 'jk/war-on-sprintf' into maint-2.7
[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_environment;
29
30 static void save_env(void)
31 {
32         int i;
33         if (saved_environment)
34                 return;
35         saved_environment = 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(void)
45 {
46         int i;
47         if (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 (orig_env[i])
52                         setenv(env_names[i], orig_env[i], 1);
53                 else
54                         unsetenv(env_names[i]);
55         }
56 }
57
58 static void commit_pager_choice(void) {
59         switch (use_pager) {
60         case 0:
61                 setenv("GIT_PAGER", "cat", 1);
62                 break;
63         case 1:
64                 setup_pager();
65                 break;
66         default:
67                 break;
68         }
69 }
70
71 static int handle_options(const char ***argv, int *argc, int *envchanged)
72 {
73         const char **orig_argv = *argv;
74
75         while (*argc > 0) {
76                 const char *cmd = (*argv)[0];
77                 if (cmd[0] != '-')
78                         break;
79
80                 /*
81                  * For legacy reasons, the "version" and "help"
82                  * commands can be written with "--" prepended
83                  * to make them look like flags.
84                  */
85                 if (!strcmp(cmd, "--help") || !strcmp(cmd, "--version"))
86                         break;
87
88                 /*
89                  * Check remaining flags.
90                  */
91                 if (skip_prefix(cmd, "--exec-path", &cmd)) {
92                         if (*cmd == '=')
93                                 git_set_argv_exec_path(cmd + 1);
94                         else {
95                                 puts(git_exec_path());
96                                 exit(0);
97                         }
98                 } else if (!strcmp(cmd, "--html-path")) {
99                         puts(system_path(GIT_HTML_PATH));
100                         exit(0);
101                 } else if (!strcmp(cmd, "--man-path")) {
102                         puts(system_path(GIT_MAN_PATH));
103                         exit(0);
104                 } else if (!strcmp(cmd, "--info-path")) {
105                         puts(system_path(GIT_INFO_PATH));
106                         exit(0);
107                 } else if (!strcmp(cmd, "-p") || !strcmp(cmd, "--paginate")) {
108                         use_pager = 1;
109                 } else if (!strcmp(cmd, "--no-pager")) {
110                         use_pager = 0;
111                         if (envchanged)
112                                 *envchanged = 1;
113                 } else if (!strcmp(cmd, "--no-replace-objects")) {
114                         check_replace_refs = 0;
115                         setenv(NO_REPLACE_OBJECTS_ENVIRONMENT, "1", 1);
116                         if (envchanged)
117                                 *envchanged = 1;
118                 } else if (!strcmp(cmd, "--git-dir")) {
119                         if (*argc < 2) {
120                                 fprintf(stderr, "No directory given for --git-dir.\n" );
121                                 usage(git_usage_string);
122                         }
123                         setenv(GIT_DIR_ENVIRONMENT, (*argv)[1], 1);
124                         if (envchanged)
125                                 *envchanged = 1;
126                         (*argv)++;
127                         (*argc)--;
128                 } else if (skip_prefix(cmd, "--git-dir=", &cmd)) {
129                         setenv(GIT_DIR_ENVIRONMENT, cmd, 1);
130                         if (envchanged)
131                                 *envchanged = 1;
132                 } else if (!strcmp(cmd, "--namespace")) {
133                         if (*argc < 2) {
134                                 fprintf(stderr, "No namespace given for --namespace.\n" );
135                                 usage(git_usage_string);
136                         }
137                         setenv(GIT_NAMESPACE_ENVIRONMENT, (*argv)[1], 1);
138                         if (envchanged)
139                                 *envchanged = 1;
140                         (*argv)++;
141                         (*argc)--;
142                 } else if (skip_prefix(cmd, "--namespace=", &cmd)) {
143                         setenv(GIT_NAMESPACE_ENVIRONMENT, cmd, 1);
144                         if (envchanged)
145                                 *envchanged = 1;
146                 } else if (!strcmp(cmd, "--work-tree")) {
147                         if (*argc < 2) {
148                                 fprintf(stderr, "No directory given for --work-tree.\n" );
149                                 usage(git_usage_string);
150                         }
151                         setenv(GIT_WORK_TREE_ENVIRONMENT, (*argv)[1], 1);
152                         if (envchanged)
153                                 *envchanged = 1;
154                         (*argv)++;
155                         (*argc)--;
156                 } else if (skip_prefix(cmd, "--work-tree=", &cmd)) {
157                         setenv(GIT_WORK_TREE_ENVIRONMENT, cmd, 1);
158                         if (envchanged)
159                                 *envchanged = 1;
160                 } else if (!strcmp(cmd, "--bare")) {
161                         char *cwd = xgetcwd();
162                         is_bare_repository_cfg = 1;
163                         setenv(GIT_DIR_ENVIRONMENT, cwd, 0);
164                         free(cwd);
165                         setenv(GIT_IMPLICIT_WORK_TREE_ENVIRONMENT, "0", 1);
166                         if (envchanged)
167                                 *envchanged = 1;
168                 } else if (!strcmp(cmd, "-c")) {
169                         if (*argc < 2) {
170                                 fprintf(stderr, "-c expects a configuration string\n" );
171                                 usage(git_usage_string);
172                         }
173                         git_config_push_parameter((*argv)[1]);
174                         (*argv)++;
175                         (*argc)--;
176                 } else if (!strcmp(cmd, "--literal-pathspecs")) {
177                         setenv(GIT_LITERAL_PATHSPECS_ENVIRONMENT, "1", 1);
178                         if (envchanged)
179                                 *envchanged = 1;
180                 } else if (!strcmp(cmd, "--no-literal-pathspecs")) {
181                         setenv(GIT_LITERAL_PATHSPECS_ENVIRONMENT, "0", 1);
182                         if (envchanged)
183                                 *envchanged = 1;
184                 } else if (!strcmp(cmd, "--glob-pathspecs")) {
185                         setenv(GIT_GLOB_PATHSPECS_ENVIRONMENT, "1", 1);
186                         if (envchanged)
187                                 *envchanged = 1;
188                 } else if (!strcmp(cmd, "--noglob-pathspecs")) {
189                         setenv(GIT_NOGLOB_PATHSPECS_ENVIRONMENT, "1", 1);
190                         if (envchanged)
191                                 *envchanged = 1;
192                 } else if (!strcmp(cmd, "--icase-pathspecs")) {
193                         setenv(GIT_ICASE_PATHSPECS_ENVIRONMENT, "1", 1);
194                         if (envchanged)
195                                 *envchanged = 1;
196                 } else if (!strcmp(cmd, "--shallow-file")) {
197                         (*argv)++;
198                         (*argc)--;
199                         set_alternate_shallow_file((*argv)[0], 1);
200                         if (envchanged)
201                                 *envchanged = 1;
202                 } else if (!strcmp(cmd, "-C")) {
203                         if (*argc < 2) {
204                                 fprintf(stderr, "No directory given for -C.\n" );
205                                 usage(git_usage_string);
206                         }
207                         if ((*argv)[1][0]) {
208                                 if (chdir((*argv)[1]))
209                                         die_errno("Cannot change to '%s'", (*argv)[1]);
210                                 if (envchanged)
211                                         *envchanged = 1;
212                         }
213                         (*argv)++;
214                         (*argc)--;
215                 } else {
216                         fprintf(stderr, "Unknown option: %s\n", cmd);
217                         usage(git_usage_string);
218                 }
219
220                 (*argv)++;
221                 (*argc)--;
222         }
223         return (*argv) - orig_argv;
224 }
225
226 static int handle_alias(int *argcp, const char ***argv)
227 {
228         int envchanged = 0, ret = 0, saved_errno = errno;
229         const char *subdir;
230         int count, option_count;
231         const char **new_argv;
232         const char *alias_command;
233         char *alias_string;
234         int unused_nongit;
235
236         subdir = setup_git_directory_gently(&unused_nongit);
237
238         alias_command = (*argv)[0];
239         alias_string = alias_lookup(alias_command);
240         if (alias_string) {
241                 if (alias_string[0] == '!') {
242                         struct child_process child = CHILD_PROCESS_INIT;
243
244                         commit_pager_choice();
245
246                         child.use_shell = 1;
247                         argv_array_push(&child.args, alias_string + 1);
248                         argv_array_pushv(&child.args, (*argv) + 1);
249
250                         ret = run_command(&child);
251                         if (ret >= 0)   /* normal exit */
252                                 exit(ret);
253
254                         die_errno("While expanding alias '%s': '%s'",
255                             alias_command, alias_string + 1);
256                 }
257                 count = split_cmdline(alias_string, &new_argv);
258                 if (count < 0)
259                         die("Bad alias.%s string: %s", alias_command,
260                             split_cmdline_strerror(count));
261                 option_count = handle_options(&new_argv, &count, &envchanged);
262                 if (envchanged)
263                         die("alias '%s' changes environment variables\n"
264                                  "You can use '!git' in the alias to do this.",
265                                  alias_command);
266                 memmove(new_argv - option_count, new_argv,
267                                 count * sizeof(char *));
268                 new_argv -= option_count;
269
270                 if (count < 1)
271                         die("empty alias for %s", alias_command);
272
273                 if (!strcmp(alias_command, new_argv[0]))
274                         die("recursive alias: %s", alias_command);
275
276                 trace_argv_printf(new_argv,
277                                   "trace: alias expansion: %s =>",
278                                   alias_command);
279
280                 REALLOC_ARRAY(new_argv, count + *argcp);
281                 /* insert after command name */
282                 memcpy(new_argv + count, *argv + 1, sizeof(char *) * *argcp);
283
284                 *argv = new_argv;
285                 *argcp += count - 1;
286
287                 ret = 1;
288         }
289
290         if (subdir && chdir(subdir))
291                 die_errno("Cannot change to '%s'", subdir);
292
293         errno = saved_errno;
294
295         return ret;
296 }
297
298 #define RUN_SETUP               (1<<0)
299 #define RUN_SETUP_GENTLY        (1<<1)
300 #define USE_PAGER               (1<<2)
301 /*
302  * require working tree to be present -- anything uses this needs
303  * RUN_SETUP for reading from the configuration file.
304  */
305 #define NEED_WORK_TREE          (1<<3)
306 #define NO_SETUP                (1<<4)
307
308 struct cmd_struct {
309         const char *cmd;
310         int (*fn)(int, const char **, const char *);
311         int option;
312 };
313
314 static int run_builtin(struct cmd_struct *p, int argc, const char **argv)
315 {
316         int status, help;
317         struct stat st;
318         const char *prefix;
319
320         prefix = NULL;
321         help = argc == 2 && !strcmp(argv[1], "-h");
322         if (!help) {
323                 if (p->option & RUN_SETUP)
324                         prefix = setup_git_directory();
325                 else if (p->option & RUN_SETUP_GENTLY) {
326                         int nongit_ok;
327                         prefix = setup_git_directory_gently(&nongit_ok);
328                 }
329
330                 if (use_pager == -1 && p->option & (RUN_SETUP | RUN_SETUP_GENTLY))
331                         use_pager = check_pager_config(p->cmd);
332                 if (use_pager == -1 && p->option & USE_PAGER)
333                         use_pager = 1;
334
335                 if ((p->option & (RUN_SETUP | RUN_SETUP_GENTLY)) &&
336                     startup_info->have_repository) /* get_git_dir() may set up repo, avoid that */
337                         trace_repo_setup(prefix);
338         }
339         commit_pager_choice();
340
341         if (!help && p->option & NEED_WORK_TREE)
342                 setup_work_tree();
343
344         trace_argv_printf(argv, "trace: built-in: git");
345
346         status = p->fn(argc, argv, prefix);
347         if (status)
348                 return status;
349
350         /* Somebody closed stdout? */
351         if (fstat(fileno(stdout), &st))
352                 return 0;
353         /* Ignore write errors for pipes and sockets.. */
354         if (S_ISFIFO(st.st_mode) || S_ISSOCK(st.st_mode))
355                 return 0;
356
357         /* Check for ENOSPC and EIO errors.. */
358         if (fflush(stdout))
359                 die_errno("write failure on standard output");
360         if (ferror(stdout))
361                 die("unknown write failure on standard output");
362         if (fclose(stdout))
363                 die_errno("close failed on standard output");
364         return 0;
365 }
366
367 static struct cmd_struct commands[] = {
368         { "add", cmd_add, RUN_SETUP | NEED_WORK_TREE },
369         { "am", cmd_am, RUN_SETUP | NEED_WORK_TREE },
370         { "annotate", cmd_annotate, RUN_SETUP },
371         { "apply", cmd_apply, RUN_SETUP_GENTLY },
372         { "archive", cmd_archive },
373         { "bisect--helper", cmd_bisect__helper, RUN_SETUP },
374         { "blame", cmd_blame, RUN_SETUP },
375         { "branch", cmd_branch, RUN_SETUP },
376         { "bundle", cmd_bundle, RUN_SETUP_GENTLY },
377         { "cat-file", cmd_cat_file, RUN_SETUP },
378         { "check-attr", cmd_check_attr, RUN_SETUP },
379         { "check-ignore", cmd_check_ignore, RUN_SETUP | NEED_WORK_TREE },
380         { "check-mailmap", cmd_check_mailmap, RUN_SETUP },
381         { "check-ref-format", cmd_check_ref_format },
382         { "checkout", cmd_checkout, RUN_SETUP | NEED_WORK_TREE },
383         { "checkout-index", cmd_checkout_index,
384                 RUN_SETUP | NEED_WORK_TREE},
385         { "cherry", cmd_cherry, RUN_SETUP },
386         { "cherry-pick", cmd_cherry_pick, RUN_SETUP | NEED_WORK_TREE },
387         { "clean", cmd_clean, RUN_SETUP | NEED_WORK_TREE },
388         { "clone", cmd_clone, NO_SETUP },
389         { "column", cmd_column, RUN_SETUP_GENTLY },
390         { "commit", cmd_commit, RUN_SETUP | NEED_WORK_TREE },
391         { "commit-tree", cmd_commit_tree, RUN_SETUP },
392         { "config", cmd_config, RUN_SETUP_GENTLY },
393         { "count-objects", cmd_count_objects, RUN_SETUP },
394         { "credential", cmd_credential, RUN_SETUP_GENTLY },
395         { "describe", cmd_describe, RUN_SETUP },
396         { "diff", cmd_diff },
397         { "diff-files", cmd_diff_files, RUN_SETUP | NEED_WORK_TREE },
398         { "diff-index", cmd_diff_index, RUN_SETUP },
399         { "diff-tree", cmd_diff_tree, RUN_SETUP },
400         { "fast-export", cmd_fast_export, RUN_SETUP },
401         { "fetch", cmd_fetch, RUN_SETUP },
402         { "fetch-pack", cmd_fetch_pack, RUN_SETUP },
403         { "fmt-merge-msg", cmd_fmt_merge_msg, RUN_SETUP },
404         { "for-each-ref", cmd_for_each_ref, RUN_SETUP },
405         { "format-patch", cmd_format_patch, RUN_SETUP },
406         { "fsck", cmd_fsck, RUN_SETUP },
407         { "fsck-objects", cmd_fsck, RUN_SETUP },
408         { "gc", cmd_gc, RUN_SETUP },
409         { "get-tar-commit-id", cmd_get_tar_commit_id },
410         { "grep", cmd_grep, RUN_SETUP_GENTLY },
411         { "hash-object", cmd_hash_object },
412         { "help", cmd_help },
413         { "index-pack", cmd_index_pack, RUN_SETUP_GENTLY },
414         { "init", cmd_init_db, NO_SETUP },
415         { "init-db", cmd_init_db, NO_SETUP },
416         { "interpret-trailers", cmd_interpret_trailers, RUN_SETUP_GENTLY },
417         { "log", cmd_log, RUN_SETUP },
418         { "ls-files", cmd_ls_files, RUN_SETUP },
419         { "ls-remote", cmd_ls_remote, RUN_SETUP_GENTLY },
420         { "ls-tree", cmd_ls_tree, RUN_SETUP },
421         { "mailinfo", cmd_mailinfo },
422         { "mailsplit", cmd_mailsplit },
423         { "merge", cmd_merge, RUN_SETUP | NEED_WORK_TREE },
424         { "merge-base", cmd_merge_base, RUN_SETUP },
425         { "merge-file", cmd_merge_file, RUN_SETUP_GENTLY },
426         { "merge-index", cmd_merge_index, RUN_SETUP },
427         { "merge-ours", cmd_merge_ours, RUN_SETUP },
428         { "merge-recursive", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE },
429         { "merge-recursive-ours", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE },
430         { "merge-recursive-theirs", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE },
431         { "merge-subtree", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE },
432         { "merge-tree", cmd_merge_tree, RUN_SETUP },
433         { "mktag", cmd_mktag, RUN_SETUP },
434         { "mktree", cmd_mktree, RUN_SETUP },
435         { "mv", cmd_mv, RUN_SETUP | NEED_WORK_TREE },
436         { "name-rev", cmd_name_rev, RUN_SETUP },
437         { "notes", cmd_notes, RUN_SETUP },
438         { "pack-objects", cmd_pack_objects, RUN_SETUP },
439         { "pack-redundant", cmd_pack_redundant, RUN_SETUP },
440         { "pack-refs", cmd_pack_refs, RUN_SETUP },
441         { "patch-id", cmd_patch_id },
442         { "pickaxe", cmd_blame, RUN_SETUP },
443         { "prune", cmd_prune, RUN_SETUP },
444         { "prune-packed", cmd_prune_packed, RUN_SETUP },
445         { "pull", cmd_pull, RUN_SETUP | NEED_WORK_TREE },
446         { "push", cmd_push, RUN_SETUP },
447         { "read-tree", cmd_read_tree, RUN_SETUP },
448         { "receive-pack", cmd_receive_pack },
449         { "reflog", cmd_reflog, RUN_SETUP },
450         { "remote", cmd_remote, RUN_SETUP },
451         { "remote-ext", cmd_remote_ext },
452         { "remote-fd", cmd_remote_fd },
453         { "repack", cmd_repack, RUN_SETUP },
454         { "replace", cmd_replace, RUN_SETUP },
455         { "rerere", cmd_rerere, RUN_SETUP },
456         { "reset", cmd_reset, RUN_SETUP },
457         { "rev-list", cmd_rev_list, RUN_SETUP },
458         { "rev-parse", cmd_rev_parse },
459         { "revert", cmd_revert, RUN_SETUP | NEED_WORK_TREE },
460         { "rm", cmd_rm, RUN_SETUP },
461         { "send-pack", cmd_send_pack, RUN_SETUP },
462         { "shortlog", cmd_shortlog, RUN_SETUP_GENTLY | USE_PAGER },
463         { "show", cmd_show, RUN_SETUP },
464         { "show-branch", cmd_show_branch, RUN_SETUP },
465         { "show-ref", cmd_show_ref, RUN_SETUP },
466         { "stage", cmd_add, RUN_SETUP | NEED_WORK_TREE },
467         { "status", cmd_status, RUN_SETUP | NEED_WORK_TREE },
468         { "stripspace", cmd_stripspace },
469         { "submodule--helper", cmd_submodule__helper, RUN_SETUP },
470         { "symbolic-ref", cmd_symbolic_ref, RUN_SETUP },
471         { "tag", cmd_tag, RUN_SETUP },
472         { "unpack-file", cmd_unpack_file, RUN_SETUP },
473         { "unpack-objects", cmd_unpack_objects, RUN_SETUP },
474         { "update-index", cmd_update_index, RUN_SETUP },
475         { "update-ref", cmd_update_ref, RUN_SETUP },
476         { "update-server-info", cmd_update_server_info, RUN_SETUP },
477         { "upload-archive", cmd_upload_archive },
478         { "upload-archive--writer", cmd_upload_archive_writer },
479         { "var", cmd_var, RUN_SETUP_GENTLY },
480         { "verify-commit", cmd_verify_commit, RUN_SETUP },
481         { "verify-pack", cmd_verify_pack },
482         { "verify-tag", cmd_verify_tag, RUN_SETUP },
483         { "version", cmd_version },
484         { "whatchanged", cmd_whatchanged, RUN_SETUP },
485         { "worktree", cmd_worktree, RUN_SETUP },
486         { "write-tree", cmd_write_tree, RUN_SETUP },
487 };
488
489 static struct cmd_struct *get_builtin(const char *s)
490 {
491         int i;
492         for (i = 0; i < ARRAY_SIZE(commands); i++) {
493                 struct cmd_struct *p = commands + i;
494                 if (!strcmp(s, p->cmd))
495                         return p;
496         }
497         return NULL;
498 }
499
500 int is_builtin(const char *s)
501 {
502         return !!get_builtin(s);
503 }
504
505 #ifdef STRIP_EXTENSION
506 static void strip_extension(const char **argv)
507 {
508         size_t len;
509
510         if (strip_suffix(argv[0], STRIP_EXTENSION, &len))
511                 argv[0] = xmemdupz(argv[0], len);
512 }
513 #else
514 #define strip_extension(cmd)
515 #endif
516
517 static void handle_builtin(int argc, const char **argv)
518 {
519         const char *cmd;
520         struct cmd_struct *builtin;
521
522         strip_extension(argv);
523         cmd = argv[0];
524
525         /* Turn "git cmd --help" into "git help cmd" */
526         if (argc > 1 && !strcmp(argv[1], "--help")) {
527                 argv[1] = argv[0];
528                 argv[0] = cmd = "help";
529         }
530
531         builtin = get_builtin(cmd);
532         if (builtin) {
533                 if (saved_environment && (builtin->option & NO_SETUP))
534                         restore_env();
535                 else
536                         exit(run_builtin(builtin, argc, argv));
537         }
538 }
539
540 static void execv_dashed_external(const char **argv)
541 {
542         struct strbuf cmd = STRBUF_INIT;
543         const char *tmp;
544         int status;
545
546         if (use_pager == -1)
547                 use_pager = check_pager_config(argv[0]);
548         commit_pager_choice();
549
550         strbuf_addf(&cmd, "git-%s", argv[0]);
551
552         /*
553          * argv[0] must be the git command, but the argv array
554          * belongs to the caller, and may be reused in
555          * subsequent loop iterations. Save argv[0] and
556          * restore it on error.
557          */
558         tmp = argv[0];
559         argv[0] = cmd.buf;
560
561         trace_argv_printf(argv, "trace: exec:");
562
563         /*
564          * if we fail because the command is not found, it is
565          * OK to return. Otherwise, we just pass along the status code.
566          */
567         status = run_command_v_opt(argv, RUN_SILENT_EXEC_FAILURE | RUN_CLEAN_ON_EXIT);
568         if (status >= 0 || errno != ENOENT)
569                 exit(status);
570
571         argv[0] = tmp;
572
573         strbuf_release(&cmd);
574 }
575
576 static int run_argv(int *argcp, const char ***argv)
577 {
578         int done_alias = 0;
579
580         while (1) {
581                 /* See if it's a builtin */
582                 handle_builtin(*argcp, *argv);
583
584                 /* .. then try the external ones */
585                 execv_dashed_external(*argv);
586
587                 /* It could be an alias -- this works around the insanity
588                  * of overriding "git log" with "git show" by having
589                  * alias.log = show
590                  */
591                 if (done_alias)
592                         break;
593                 save_env();
594                 if (!handle_alias(argcp, argv))
595                         break;
596                 done_alias = 1;
597         }
598
599         return done_alias;
600 }
601
602 /*
603  * Many parts of Git have subprograms communicate via pipe, expect the
604  * upstream of a pipe to die with SIGPIPE when the downstream of a
605  * pipe does not need to read all that is written.  Some third-party
606  * programs that ignore or block SIGPIPE for their own reason forget
607  * to restore SIGPIPE handling to the default before spawning Git and
608  * break this carefully orchestrated machinery.
609  *
610  * Restore the way SIGPIPE is handled to default, which is what we
611  * expect.
612  */
613 static void restore_sigpipe_to_default(void)
614 {
615         sigset_t unblock;
616
617         sigemptyset(&unblock);
618         sigaddset(&unblock, SIGPIPE);
619         sigprocmask(SIG_UNBLOCK, &unblock, NULL);
620         signal(SIGPIPE, SIG_DFL);
621 }
622
623 int main(int argc, char **av)
624 {
625         const char **argv = (const char **) av;
626         const char *cmd;
627         int done_help = 0;
628
629         startup_info = &git_startup_info;
630
631         cmd = git_extract_argv0_path(argv[0]);
632         if (!cmd)
633                 cmd = "git-help";
634
635         /*
636          * Always open file descriptors 0/1/2 to avoid clobbering files
637          * in die().  It also avoids messing up when the pipes are dup'ed
638          * onto stdin/stdout/stderr in the child processes we spawn.
639          */
640         sanitize_stdfds();
641
642         restore_sigpipe_to_default();
643
644         git_setup_gettext();
645
646         trace_command_performance(argv);
647
648         /*
649          * "git-xxxx" is the same as "git xxxx", but we obviously:
650          *
651          *  - cannot take flags in between the "git" and the "xxxx".
652          *  - cannot execute it externally (since it would just do
653          *    the same thing over again)
654          *
655          * So we just directly call the builtin handler, and die if
656          * that one cannot handle it.
657          */
658         if (skip_prefix(cmd, "git-", &cmd)) {
659                 argv[0] = cmd;
660                 handle_builtin(argc, argv);
661                 die("cannot handle %s as a builtin", cmd);
662         }
663
664         /* Look for flags.. */
665         argv++;
666         argc--;
667         handle_options(&argv, &argc, NULL);
668         if (argc > 0) {
669                 /* translate --help and --version into commands */
670                 skip_prefix(argv[0], "--", &argv[0]);
671         } else {
672                 /* The user didn't specify a command; give them help */
673                 commit_pager_choice();
674                 printf("usage: %s\n\n", git_usage_string);
675                 list_common_cmds_help();
676                 printf("\n%s\n", _(git_more_info_string));
677                 exit(1);
678         }
679         cmd = argv[0];
680
681         /*
682          * We use PATH to find git commands, but we prepend some higher
683          * precedence paths: the "--exec-path" option, the GIT_EXEC_PATH
684          * environment, and the $(gitexecdir) from the Makefile at build
685          * time.
686          */
687         setup_path();
688
689         while (1) {
690                 int was_alias = run_argv(&argc, &argv);
691                 if (errno != ENOENT)
692                         break;
693                 if (was_alias) {
694                         fprintf(stderr, "Expansion of alias '%s' failed; "
695                                 "'%s' is not a git command\n",
696                                 cmd, argv[0]);
697                         exit(1);
698                 }
699                 if (!done_help) {
700                         cmd = argv[0] = help_unknown_cmd(cmd);
701                         done_help = 1;
702                 } else
703                         break;
704         }
705
706         fprintf(stderr, "Failed to run command '%s': %s\n",
707                 cmd, strerror(errno));
708
709         return 1;
710 }