Merge branch 'rs/realloc-array'
[git] / git.c
1 #include "builtin.h"
2 #include "cache.h"
3 #include "exec_cmd.h"
4 #include "help.h"
5 #include "quote.h"
6 #include "run-command.h"
7 #include "commit.h"
8
9 const char git_usage_string[] =
10         "git [--version] [--help] [-C <path>] [-c name=value]\n"
11         "           [--exec-path[=<path>]] [--html-path] [--man-path] [--info-path]\n"
12         "           [-p|--paginate|--no-pager] [--no-replace-objects] [--bare]\n"
13         "           [--git-dir=<path>] [--work-tree=<path>] [--namespace=<name>]\n"
14         "           <command> [<args>]";
15
16 const char git_more_info_string[] =
17         N_("'git help -a' and 'git help -g' list available subcommands and some\n"
18            "concept guides. See 'git help <command>' or 'git help <concept>'\n"
19            "to read about a specific subcommand or concept.");
20
21 static struct startup_info git_startup_info;
22 static int use_pager = -1;
23 static char *orig_cwd;
24 static const char *env_names[] = {
25         GIT_DIR_ENVIRONMENT,
26         GIT_WORK_TREE_ENVIRONMENT,
27         GIT_IMPLICIT_WORK_TREE_ENVIRONMENT,
28         GIT_PREFIX_ENVIRONMENT
29 };
30 static char *orig_env[4];
31 static int saved_environment;
32
33 static void save_env(void)
34 {
35         int i;
36         if (saved_environment)
37                 return;
38         saved_environment = 1;
39         orig_cwd = xgetcwd();
40         for (i = 0; i < ARRAY_SIZE(env_names); i++) {
41                 orig_env[i] = getenv(env_names[i]);
42                 if (orig_env[i])
43                         orig_env[i] = xstrdup(orig_env[i]);
44         }
45 }
46
47 static void restore_env(void)
48 {
49         int i;
50         if (orig_cwd && chdir(orig_cwd))
51                 die_errno("could not move to %s", orig_cwd);
52         free(orig_cwd);
53         for (i = 0; i < ARRAY_SIZE(env_names); i++) {
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 (chdir((*argv)[1]))
211                                 die_errno("Cannot change to '%s'", (*argv)[1]);
212                         if (envchanged)
213                                 *envchanged = 1;
214                         (*argv)++;
215                         (*argc)--;
216                 } else {
217                         fprintf(stderr, "Unknown option: %s\n", cmd);
218                         usage(git_usage_string);
219                 }
220
221                 (*argv)++;
222                 (*argc)--;
223         }
224         return (*argv) - orig_argv;
225 }
226
227 static int handle_alias(int *argcp, const char ***argv)
228 {
229         int envchanged = 0, ret = 0, saved_errno = errno;
230         const char *subdir;
231         int count, option_count;
232         const char **new_argv;
233         const char *alias_command;
234         char *alias_string;
235         int unused_nongit;
236
237         subdir = setup_git_directory_gently(&unused_nongit);
238
239         alias_command = (*argv)[0];
240         alias_string = alias_lookup(alias_command);
241         if (alias_string) {
242                 if (alias_string[0] == '!') {
243                         const char **alias_argv;
244                         int argc = *argcp, i;
245
246                         commit_pager_choice();
247
248                         /* build alias_argv */
249                         alias_argv = xmalloc(sizeof(*alias_argv) * (argc + 1));
250                         alias_argv[0] = alias_string + 1;
251                         for (i = 1; i < argc; ++i)
252                                 alias_argv[i] = (*argv)[i];
253                         alias_argv[argc] = NULL;
254
255                         ret = run_command_v_opt(alias_argv, RUN_USING_SHELL);
256                         if (ret >= 0)   /* normal exit */
257                                 exit(ret);
258
259                         die_errno("While expanding alias '%s': '%s'",
260                             alias_command, alias_string + 1);
261                 }
262                 count = split_cmdline(alias_string, &new_argv);
263                 if (count < 0)
264                         die("Bad alias.%s string: %s", alias_command,
265                             split_cmdline_strerror(count));
266                 option_count = handle_options(&new_argv, &count, &envchanged);
267                 if (envchanged)
268                         die("alias '%s' changes environment variables\n"
269                                  "You can use '!git' in the alias to do this.",
270                                  alias_command);
271                 memmove(new_argv - option_count, new_argv,
272                                 count * sizeof(char *));
273                 new_argv -= option_count;
274
275                 if (count < 1)
276                         die("empty alias for %s", alias_command);
277
278                 if (!strcmp(alias_command, new_argv[0]))
279                         die("recursive alias: %s", alias_command);
280
281                 trace_argv_printf(new_argv,
282                                   "trace: alias expansion: %s =>",
283                                   alias_command);
284
285                 REALLOC_ARRAY(new_argv, count + *argcp);
286                 /* insert after command name */
287                 memcpy(new_argv + count, *argv + 1, sizeof(char *) * *argcp);
288
289                 *argv = new_argv;
290                 *argcp += count - 1;
291
292                 ret = 1;
293         }
294
295         if (subdir && chdir(subdir))
296                 die_errno("Cannot change to '%s'", subdir);
297
298         errno = saved_errno;
299
300         return ret;
301 }
302
303 #define RUN_SETUP               (1<<0)
304 #define RUN_SETUP_GENTLY        (1<<1)
305 #define USE_PAGER               (1<<2)
306 /*
307  * require working tree to be present -- anything uses this needs
308  * RUN_SETUP for reading from the configuration file.
309  */
310 #define NEED_WORK_TREE          (1<<3)
311 #define NO_SETUP                (1<<4)
312
313 struct cmd_struct {
314         const char *cmd;
315         int (*fn)(int, const char **, const char *);
316         int option;
317 };
318
319 static int run_builtin(struct cmd_struct *p, int argc, const char **argv)
320 {
321         int status, help;
322         struct stat st;
323         const char *prefix;
324
325         prefix = NULL;
326         help = argc == 2 && !strcmp(argv[1], "-h");
327         if (!help) {
328                 if (p->option & RUN_SETUP)
329                         prefix = setup_git_directory();
330                 else if (p->option & RUN_SETUP_GENTLY) {
331                         int nongit_ok;
332                         prefix = setup_git_directory_gently(&nongit_ok);
333                 }
334
335                 if (use_pager == -1 && p->option & (RUN_SETUP | RUN_SETUP_GENTLY))
336                         use_pager = check_pager_config(p->cmd);
337                 if (use_pager == -1 && p->option & USE_PAGER)
338                         use_pager = 1;
339
340                 if ((p->option & (RUN_SETUP | RUN_SETUP_GENTLY)) &&
341                     startup_info->have_repository) /* get_git_dir() may set up repo, avoid that */
342                         trace_repo_setup(prefix);
343         }
344         commit_pager_choice();
345
346         if (!help && p->option & NEED_WORK_TREE)
347                 setup_work_tree();
348
349         trace_argv_printf(argv, "trace: built-in: git");
350
351         status = p->fn(argc, argv, prefix);
352         if (status)
353                 return status;
354
355         /* Somebody closed stdout? */
356         if (fstat(fileno(stdout), &st))
357                 return 0;
358         /* Ignore write errors for pipes and sockets.. */
359         if (S_ISFIFO(st.st_mode) || S_ISSOCK(st.st_mode))
360                 return 0;
361
362         /* Check for ENOSPC and EIO errors.. */
363         if (fflush(stdout))
364                 die_errno("write failure on standard output");
365         if (ferror(stdout))
366                 die("unknown write failure on standard output");
367         if (fclose(stdout))
368                 die_errno("close failed on standard output");
369         return 0;
370 }
371
372 static struct cmd_struct commands[] = {
373         { "add", cmd_add, RUN_SETUP | NEED_WORK_TREE },
374         { "annotate", cmd_annotate, RUN_SETUP },
375         { "apply", cmd_apply, RUN_SETUP_GENTLY },
376         { "archive", cmd_archive },
377         { "bisect--helper", cmd_bisect__helper, RUN_SETUP },
378         { "blame", cmd_blame, RUN_SETUP },
379         { "branch", cmd_branch, RUN_SETUP },
380         { "bundle", cmd_bundle, RUN_SETUP_GENTLY },
381         { "cat-file", cmd_cat_file, RUN_SETUP },
382         { "check-attr", cmd_check_attr, RUN_SETUP },
383         { "check-ignore", cmd_check_ignore, RUN_SETUP | NEED_WORK_TREE },
384         { "check-mailmap", cmd_check_mailmap, RUN_SETUP },
385         { "check-ref-format", cmd_check_ref_format },
386         { "checkout", cmd_checkout, RUN_SETUP | NEED_WORK_TREE },
387         { "checkout-index", cmd_checkout_index,
388                 RUN_SETUP | NEED_WORK_TREE},
389         { "cherry", cmd_cherry, RUN_SETUP },
390         { "cherry-pick", cmd_cherry_pick, RUN_SETUP | NEED_WORK_TREE },
391         { "clean", cmd_clean, RUN_SETUP | NEED_WORK_TREE },
392         { "clone", cmd_clone, NO_SETUP },
393         { "column", cmd_column, RUN_SETUP_GENTLY },
394         { "commit", cmd_commit, RUN_SETUP | NEED_WORK_TREE },
395         { "commit-tree", cmd_commit_tree, RUN_SETUP },
396         { "config", cmd_config, RUN_SETUP_GENTLY },
397         { "count-objects", cmd_count_objects, RUN_SETUP },
398         { "credential", cmd_credential, RUN_SETUP_GENTLY },
399         { "describe", cmd_describe, RUN_SETUP },
400         { "diff", cmd_diff },
401         { "diff-files", cmd_diff_files, RUN_SETUP | NEED_WORK_TREE },
402         { "diff-index", cmd_diff_index, RUN_SETUP },
403         { "diff-tree", cmd_diff_tree, RUN_SETUP },
404         { "fast-export", cmd_fast_export, RUN_SETUP },
405         { "fetch", cmd_fetch, RUN_SETUP },
406         { "fetch-pack", cmd_fetch_pack, RUN_SETUP },
407         { "fmt-merge-msg", cmd_fmt_merge_msg, RUN_SETUP },
408         { "for-each-ref", cmd_for_each_ref, RUN_SETUP },
409         { "format-patch", cmd_format_patch, RUN_SETUP },
410         { "fsck", cmd_fsck, RUN_SETUP },
411         { "fsck-objects", cmd_fsck, RUN_SETUP },
412         { "gc", cmd_gc, RUN_SETUP },
413         { "get-tar-commit-id", cmd_get_tar_commit_id },
414         { "grep", cmd_grep, RUN_SETUP_GENTLY },
415         { "hash-object", cmd_hash_object },
416         { "help", cmd_help },
417         { "index-pack", cmd_index_pack, RUN_SETUP_GENTLY },
418         { "init", cmd_init_db, NO_SETUP },
419         { "init-db", cmd_init_db, NO_SETUP },
420         { "log", cmd_log, RUN_SETUP },
421         { "ls-files", cmd_ls_files, RUN_SETUP },
422         { "ls-remote", cmd_ls_remote, RUN_SETUP_GENTLY },
423         { "ls-tree", cmd_ls_tree, RUN_SETUP },
424         { "mailinfo", cmd_mailinfo },
425         { "mailsplit", cmd_mailsplit },
426         { "merge", cmd_merge, RUN_SETUP | NEED_WORK_TREE },
427         { "merge-base", cmd_merge_base, RUN_SETUP },
428         { "merge-file", cmd_merge_file, RUN_SETUP_GENTLY },
429         { "merge-index", cmd_merge_index, RUN_SETUP },
430         { "merge-ours", cmd_merge_ours, RUN_SETUP },
431         { "merge-recursive", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE },
432         { "merge-recursive-ours", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE },
433         { "merge-recursive-theirs", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE },
434         { "merge-subtree", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE },
435         { "merge-tree", cmd_merge_tree, RUN_SETUP },
436         { "mktag", cmd_mktag, RUN_SETUP },
437         { "mktree", cmd_mktree, RUN_SETUP },
438         { "mv", cmd_mv, RUN_SETUP | NEED_WORK_TREE },
439         { "name-rev", cmd_name_rev, RUN_SETUP },
440         { "notes", cmd_notes, RUN_SETUP },
441         { "pack-objects", cmd_pack_objects, RUN_SETUP },
442         { "pack-redundant", cmd_pack_redundant, RUN_SETUP },
443         { "pack-refs", cmd_pack_refs, RUN_SETUP },
444         { "patch-id", cmd_patch_id },
445         { "pickaxe", cmd_blame, RUN_SETUP },
446         { "prune", cmd_prune, RUN_SETUP },
447         { "prune-packed", cmd_prune_packed, RUN_SETUP },
448         { "push", cmd_push, RUN_SETUP },
449         { "read-tree", cmd_read_tree, RUN_SETUP },
450         { "receive-pack", cmd_receive_pack },
451         { "reflog", cmd_reflog, RUN_SETUP },
452         { "remote", cmd_remote, RUN_SETUP },
453         { "remote-ext", cmd_remote_ext },
454         { "remote-fd", cmd_remote_fd },
455         { "repack", cmd_repack, RUN_SETUP },
456         { "replace", cmd_replace, RUN_SETUP },
457         { "rerere", cmd_rerere, RUN_SETUP },
458         { "reset", cmd_reset, RUN_SETUP },
459         { "rev-list", cmd_rev_list, RUN_SETUP },
460         { "rev-parse", cmd_rev_parse },
461         { "revert", cmd_revert, RUN_SETUP | NEED_WORK_TREE },
462         { "rm", cmd_rm, RUN_SETUP },
463         { "send-pack", cmd_send_pack, RUN_SETUP },
464         { "shortlog", cmd_shortlog, RUN_SETUP_GENTLY | USE_PAGER },
465         { "show", cmd_show, RUN_SETUP },
466         { "show-branch", cmd_show_branch, RUN_SETUP },
467         { "show-ref", cmd_show_ref, RUN_SETUP },
468         { "stage", cmd_add, RUN_SETUP | NEED_WORK_TREE },
469         { "status", cmd_status, RUN_SETUP | NEED_WORK_TREE },
470         { "stripspace", cmd_stripspace },
471         { "symbolic-ref", cmd_symbolic_ref, RUN_SETUP },
472         { "tag", cmd_tag, RUN_SETUP },
473         { "unpack-file", cmd_unpack_file, RUN_SETUP },
474         { "unpack-objects", cmd_unpack_objects, RUN_SETUP },
475         { "update-index", cmd_update_index, RUN_SETUP },
476         { "update-ref", cmd_update_ref, RUN_SETUP },
477         { "update-server-info", cmd_update_server_info, RUN_SETUP },
478         { "upload-archive", cmd_upload_archive },
479         { "upload-archive--writer", cmd_upload_archive_writer },
480         { "var", cmd_var, RUN_SETUP_GENTLY },
481         { "verify-commit", cmd_verify_commit, RUN_SETUP },
482         { "verify-pack", cmd_verify_pack },
483         { "verify-tag", cmd_verify_tag, RUN_SETUP },
484         { "version", cmd_version },
485         { "whatchanged", cmd_whatchanged, RUN_SETUP },
486         { "write-tree", cmd_write_tree, RUN_SETUP },
487 };
488
489 int is_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 1;
496         }
497         return 0;
498 }
499
500 static void handle_builtin(int argc, const char **argv)
501 {
502         const char *cmd = argv[0];
503         int i;
504         static const char ext[] = STRIP_EXTENSION;
505
506         if (sizeof(ext) > 1) {
507                 i = strlen(argv[0]) - strlen(ext);
508                 if (i > 0 && !strcmp(argv[0] + i, ext)) {
509                         char *argv0 = xstrdup(argv[0]);
510                         argv[0] = cmd = argv0;
511                         argv0[i] = '\0';
512                 }
513         }
514
515         /* Turn "git cmd --help" into "git help cmd" */
516         if (argc > 1 && !strcmp(argv[1], "--help")) {
517                 argv[1] = argv[0];
518                 argv[0] = cmd = "help";
519         }
520
521         for (i = 0; i < ARRAY_SIZE(commands); i++) {
522                 struct cmd_struct *p = commands+i;
523                 if (strcmp(p->cmd, cmd))
524                         continue;
525                 if (saved_environment && (p->option & NO_SETUP)) {
526                         restore_env();
527                         break;
528                 }
529                 exit(run_builtin(p, argc, argv));
530         }
531 }
532
533 static void execv_dashed_external(const char **argv)
534 {
535         struct strbuf cmd = STRBUF_INIT;
536         const char *tmp;
537         int status;
538
539         if (use_pager == -1)
540                 use_pager = check_pager_config(argv[0]);
541         commit_pager_choice();
542
543         strbuf_addf(&cmd, "git-%s", argv[0]);
544
545         /*
546          * argv[0] must be the git command, but the argv array
547          * belongs to the caller, and may be reused in
548          * subsequent loop iterations. Save argv[0] and
549          * restore it on error.
550          */
551         tmp = argv[0];
552         argv[0] = cmd.buf;
553
554         trace_argv_printf(argv, "trace: exec:");
555
556         /*
557          * if we fail because the command is not found, it is
558          * OK to return. Otherwise, we just pass along the status code.
559          */
560         status = run_command_v_opt(argv, RUN_SILENT_EXEC_FAILURE | RUN_CLEAN_ON_EXIT);
561         if (status >= 0 || errno != ENOENT)
562                 exit(status);
563
564         argv[0] = tmp;
565
566         strbuf_release(&cmd);
567 }
568
569 static int run_argv(int *argcp, const char ***argv)
570 {
571         int done_alias = 0;
572
573         while (1) {
574                 /* See if it's a builtin */
575                 handle_builtin(*argcp, *argv);
576
577                 /* .. then try the external ones */
578                 execv_dashed_external(*argv);
579
580                 /* It could be an alias -- this works around the insanity
581                  * of overriding "git log" with "git show" by having
582                  * alias.log = show
583                  */
584                 if (done_alias)
585                         break;
586                 save_env();
587                 if (!handle_alias(argcp, argv))
588                         break;
589                 done_alias = 1;
590         }
591
592         return done_alias;
593 }
594
595
596 int main(int argc, char **av)
597 {
598         const char **argv = (const char **) av;
599         const char *cmd;
600
601         startup_info = &git_startup_info;
602
603         cmd = git_extract_argv0_path(argv[0]);
604         if (!cmd)
605                 cmd = "git-help";
606
607         /*
608          * Always open file descriptors 0/1/2 to avoid clobbering files
609          * in die().  It also avoids messing up when the pipes are dup'ed
610          * onto stdin/stdout/stderr in the child processes we spawn.
611          */
612         sanitize_stdfds();
613
614         git_setup_gettext();
615
616         trace_command_performance(argv);
617
618         /*
619          * "git-xxxx" is the same as "git xxxx", but we obviously:
620          *
621          *  - cannot take flags in between the "git" and the "xxxx".
622          *  - cannot execute it externally (since it would just do
623          *    the same thing over again)
624          *
625          * So we just directly call the builtin handler, and die if
626          * that one cannot handle it.
627          */
628         if (skip_prefix(cmd, "git-", &cmd)) {
629                 argv[0] = cmd;
630                 handle_builtin(argc, argv);
631                 die("cannot handle %s as a builtin", cmd);
632         }
633
634         /* Look for flags.. */
635         argv++;
636         argc--;
637         handle_options(&argv, &argc, NULL);
638         if (argc > 0) {
639                 /* translate --help and --version into commands */
640                 skip_prefix(argv[0], "--", &argv[0]);
641         } else {
642                 /* The user didn't specify a command; give them help */
643                 commit_pager_choice();
644                 printf("usage: %s\n\n", git_usage_string);
645                 list_common_cmds_help();
646                 printf("\n%s\n", _(git_more_info_string));
647                 exit(1);
648         }
649         cmd = argv[0];
650
651         /*
652          * We use PATH to find git commands, but we prepend some higher
653          * precedence paths: the "--exec-path" option, the GIT_EXEC_PATH
654          * environment, and the $(gitexecdir) from the Makefile at build
655          * time.
656          */
657         setup_path();
658
659         while (1) {
660                 static int done_help = 0;
661                 static int was_alias = 0;
662                 was_alias = run_argv(&argc, &argv);
663                 if (errno != ENOENT)
664                         break;
665                 if (was_alias) {
666                         fprintf(stderr, "Expansion of alias '%s' failed; "
667                                 "'%s' is not a git command\n",
668                                 cmd, argv[0]);
669                         exit(1);
670                 }
671                 if (!done_help) {
672                         cmd = argv[0] = help_unknown_cmd(cmd);
673                         done_help = 1;
674                 } else
675                         break;
676         }
677
678         fprintf(stderr, "Failed to run command '%s': %s\n",
679                 cmd, strerror(errno));
680
681         return 1;
682 }