Merge branch 'rt/bfg-ad-in-filter-branch-doc'
[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' lists 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
24 static void commit_pager_choice(void) {
25         switch (use_pager) {
26         case 0:
27                 setenv("GIT_PAGER", "cat", 1);
28                 break;
29         case 1:
30                 setup_pager();
31                 break;
32         default:
33                 break;
34         }
35 }
36
37 static int handle_options(const char ***argv, int *argc, int *envchanged)
38 {
39         const char **orig_argv = *argv;
40
41         while (*argc > 0) {
42                 const char *cmd = (*argv)[0];
43                 if (cmd[0] != '-')
44                         break;
45
46                 /*
47                  * For legacy reasons, the "version" and "help"
48                  * commands can be written with "--" prepended
49                  * to make them look like flags.
50                  */
51                 if (!strcmp(cmd, "--help") || !strcmp(cmd, "--version"))
52                         break;
53
54                 /*
55                  * Check remaining flags.
56                  */
57                 if (starts_with(cmd, "--exec-path")) {
58                         cmd += 11;
59                         if (*cmd == '=')
60                                 git_set_argv_exec_path(cmd + 1);
61                         else {
62                                 puts(git_exec_path());
63                                 exit(0);
64                         }
65                 } else if (!strcmp(cmd, "--html-path")) {
66                         puts(system_path(GIT_HTML_PATH));
67                         exit(0);
68                 } else if (!strcmp(cmd, "--man-path")) {
69                         puts(system_path(GIT_MAN_PATH));
70                         exit(0);
71                 } else if (!strcmp(cmd, "--info-path")) {
72                         puts(system_path(GIT_INFO_PATH));
73                         exit(0);
74                 } else if (!strcmp(cmd, "-p") || !strcmp(cmd, "--paginate")) {
75                         use_pager = 1;
76                 } else if (!strcmp(cmd, "--no-pager")) {
77                         use_pager = 0;
78                         if (envchanged)
79                                 *envchanged = 1;
80                 } else if (!strcmp(cmd, "--no-replace-objects")) {
81                         read_replace_refs = 0;
82                         setenv(NO_REPLACE_OBJECTS_ENVIRONMENT, "1", 1);
83                         if (envchanged)
84                                 *envchanged = 1;
85                 } else if (!strcmp(cmd, "--git-dir")) {
86                         if (*argc < 2) {
87                                 fprintf(stderr, "No directory given for --git-dir.\n" );
88                                 usage(git_usage_string);
89                         }
90                         setenv(GIT_DIR_ENVIRONMENT, (*argv)[1], 1);
91                         if (envchanged)
92                                 *envchanged = 1;
93                         (*argv)++;
94                         (*argc)--;
95                 } else if (starts_with(cmd, "--git-dir=")) {
96                         setenv(GIT_DIR_ENVIRONMENT, cmd + 10, 1);
97                         if (envchanged)
98                                 *envchanged = 1;
99                 } else if (!strcmp(cmd, "--namespace")) {
100                         if (*argc < 2) {
101                                 fprintf(stderr, "No namespace given for --namespace.\n" );
102                                 usage(git_usage_string);
103                         }
104                         setenv(GIT_NAMESPACE_ENVIRONMENT, (*argv)[1], 1);
105                         if (envchanged)
106                                 *envchanged = 1;
107                         (*argv)++;
108                         (*argc)--;
109                 } else if (starts_with(cmd, "--namespace=")) {
110                         setenv(GIT_NAMESPACE_ENVIRONMENT, cmd + 12, 1);
111                         if (envchanged)
112                                 *envchanged = 1;
113                 } else if (!strcmp(cmd, "--work-tree")) {
114                         if (*argc < 2) {
115                                 fprintf(stderr, "No directory given for --work-tree.\n" );
116                                 usage(git_usage_string);
117                         }
118                         setenv(GIT_WORK_TREE_ENVIRONMENT, (*argv)[1], 1);
119                         if (envchanged)
120                                 *envchanged = 1;
121                         (*argv)++;
122                         (*argc)--;
123                 } else if (starts_with(cmd, "--work-tree=")) {
124                         setenv(GIT_WORK_TREE_ENVIRONMENT, cmd + 12, 1);
125                         if (envchanged)
126                                 *envchanged = 1;
127                 } else if (!strcmp(cmd, "--bare")) {
128                         static char git_dir[PATH_MAX+1];
129                         is_bare_repository_cfg = 1;
130                         setenv(GIT_DIR_ENVIRONMENT, getcwd(git_dir, sizeof(git_dir)), 0);
131                         setenv(GIT_IMPLICIT_WORK_TREE_ENVIRONMENT, "0", 1);
132                         if (envchanged)
133                                 *envchanged = 1;
134                 } else if (!strcmp(cmd, "-c")) {
135                         if (*argc < 2) {
136                                 fprintf(stderr, "-c expects a configuration string\n" );
137                                 usage(git_usage_string);
138                         }
139                         git_config_push_parameter((*argv)[1]);
140                         (*argv)++;
141                         (*argc)--;
142                 } else if (!strcmp(cmd, "--literal-pathspecs")) {
143                         setenv(GIT_LITERAL_PATHSPECS_ENVIRONMENT, "1", 1);
144                         if (envchanged)
145                                 *envchanged = 1;
146                 } else if (!strcmp(cmd, "--no-literal-pathspecs")) {
147                         setenv(GIT_LITERAL_PATHSPECS_ENVIRONMENT, "0", 1);
148                         if (envchanged)
149                                 *envchanged = 1;
150                 } else if (!strcmp(cmd, "--glob-pathspecs")) {
151                         setenv(GIT_GLOB_PATHSPECS_ENVIRONMENT, "1", 1);
152                         if (envchanged)
153                                 *envchanged = 1;
154                 } else if (!strcmp(cmd, "--noglob-pathspecs")) {
155                         setenv(GIT_NOGLOB_PATHSPECS_ENVIRONMENT, "1", 1);
156                         if (envchanged)
157                                 *envchanged = 1;
158                 } else if (!strcmp(cmd, "--icase-pathspecs")) {
159                         setenv(GIT_ICASE_PATHSPECS_ENVIRONMENT, "1", 1);
160                         if (envchanged)
161                                 *envchanged = 1;
162                 } else if (!strcmp(cmd, "--shallow-file")) {
163                         (*argv)++;
164                         (*argc)--;
165                         set_alternate_shallow_file((*argv)[0]);
166                         if (envchanged)
167                                 *envchanged = 1;
168                 } else if (!strcmp(cmd, "-C")) {
169                         if (*argc < 2) {
170                                 fprintf(stderr, "No directory given for -C.\n" );
171                                 usage(git_usage_string);
172                         }
173                         if (chdir((*argv)[1]))
174                                 die_errno("Cannot change to '%s'", (*argv)[1]);
175                         if (envchanged)
176                                 *envchanged = 1;
177                         (*argv)++;
178                         (*argc)--;
179                 } else {
180                         fprintf(stderr, "Unknown option: %s\n", cmd);
181                         usage(git_usage_string);
182                 }
183
184                 (*argv)++;
185                 (*argc)--;
186         }
187         return (*argv) - orig_argv;
188 }
189
190 static int handle_alias(int *argcp, const char ***argv)
191 {
192         int envchanged = 0, ret = 0, saved_errno = errno;
193         const char *subdir;
194         int count, option_count;
195         const char **new_argv;
196         const char *alias_command;
197         char *alias_string;
198         int unused_nongit;
199
200         subdir = setup_git_directory_gently(&unused_nongit);
201
202         alias_command = (*argv)[0];
203         alias_string = alias_lookup(alias_command);
204         if (alias_string) {
205                 if (alias_string[0] == '!') {
206                         const char **alias_argv;
207                         int argc = *argcp, i;
208
209                         commit_pager_choice();
210
211                         /* build alias_argv */
212                         alias_argv = xmalloc(sizeof(*alias_argv) * (argc + 1));
213                         alias_argv[0] = alias_string + 1;
214                         for (i = 1; i < argc; ++i)
215                                 alias_argv[i] = (*argv)[i];
216                         alias_argv[argc] = NULL;
217
218                         ret = run_command_v_opt(alias_argv, RUN_USING_SHELL);
219                         if (ret >= 0)   /* normal exit */
220                                 exit(ret);
221
222                         die_errno("While expanding alias '%s': '%s'",
223                             alias_command, alias_string + 1);
224                 }
225                 count = split_cmdline(alias_string, &new_argv);
226                 if (count < 0)
227                         die("Bad alias.%s string: %s", alias_command,
228                             split_cmdline_strerror(count));
229                 option_count = handle_options(&new_argv, &count, &envchanged);
230                 if (envchanged)
231                         die("alias '%s' changes environment variables\n"
232                                  "You can use '!git' in the alias to do this.",
233                                  alias_command);
234                 memmove(new_argv - option_count, new_argv,
235                                 count * sizeof(char *));
236                 new_argv -= option_count;
237
238                 if (count < 1)
239                         die("empty alias for %s", alias_command);
240
241                 if (!strcmp(alias_command, new_argv[0]))
242                         die("recursive alias: %s", alias_command);
243
244                 trace_argv_printf(new_argv,
245                                   "trace: alias expansion: %s =>",
246                                   alias_command);
247
248                 new_argv = xrealloc(new_argv, sizeof(char *) *
249                                     (count + *argcp));
250                 /* insert after command name */
251                 memcpy(new_argv + count, *argv + 1, sizeof(char *) * *argcp);
252
253                 *argv = new_argv;
254                 *argcp += count - 1;
255
256                 ret = 1;
257         }
258
259         if (subdir && chdir(subdir))
260                 die_errno("Cannot change to '%s'", subdir);
261
262         errno = saved_errno;
263
264         return ret;
265 }
266
267 #define RUN_SETUP               (1<<0)
268 #define RUN_SETUP_GENTLY        (1<<1)
269 #define USE_PAGER               (1<<2)
270 /*
271  * require working tree to be present -- anything uses this needs
272  * RUN_SETUP for reading from the configuration file.
273  */
274 #define NEED_WORK_TREE          (1<<3)
275
276 struct cmd_struct {
277         const char *cmd;
278         int (*fn)(int, const char **, const char *);
279         int option;
280 };
281
282 static int run_builtin(struct cmd_struct *p, int argc, const char **argv)
283 {
284         int status, help;
285         struct stat st;
286         const char *prefix;
287
288         prefix = NULL;
289         help = argc == 2 && !strcmp(argv[1], "-h");
290         if (!help) {
291                 if (p->option & RUN_SETUP)
292                         prefix = setup_git_directory();
293                 if (p->option & RUN_SETUP_GENTLY) {
294                         int nongit_ok;
295                         prefix = setup_git_directory_gently(&nongit_ok);
296                 }
297
298                 if (use_pager == -1 && p->option & (RUN_SETUP | RUN_SETUP_GENTLY))
299                         use_pager = check_pager_config(p->cmd);
300                 if (use_pager == -1 && p->option & USE_PAGER)
301                         use_pager = 1;
302
303                 if ((p->option & (RUN_SETUP | RUN_SETUP_GENTLY)) &&
304                     startup_info->have_repository) /* get_git_dir() may set up repo, avoid that */
305                         trace_repo_setup(prefix);
306         }
307         commit_pager_choice();
308
309         if (!help && p->option & NEED_WORK_TREE)
310                 setup_work_tree();
311
312         trace_argv_printf(argv, "trace: built-in: git");
313
314         status = p->fn(argc, argv, prefix);
315         if (status)
316                 return status;
317
318         /* Somebody closed stdout? */
319         if (fstat(fileno(stdout), &st))
320                 return 0;
321         /* Ignore write errors for pipes and sockets.. */
322         if (S_ISFIFO(st.st_mode) || S_ISSOCK(st.st_mode))
323                 return 0;
324
325         /* Check for ENOSPC and EIO errors.. */
326         if (fflush(stdout))
327                 die_errno("write failure on standard output");
328         if (ferror(stdout))
329                 die("unknown write failure on standard output");
330         if (fclose(stdout))
331                 die_errno("close failed on standard output");
332         return 0;
333 }
334
335 static void handle_internal_command(int argc, const char **argv)
336 {
337         const char *cmd = argv[0];
338         static struct cmd_struct commands[] = {
339                 { "add", cmd_add, RUN_SETUP | NEED_WORK_TREE },
340                 { "annotate", cmd_annotate, RUN_SETUP },
341                 { "apply", cmd_apply, RUN_SETUP_GENTLY },
342                 { "archive", cmd_archive },
343                 { "bisect--helper", cmd_bisect__helper, RUN_SETUP },
344                 { "blame", cmd_blame, RUN_SETUP },
345                 { "branch", cmd_branch, RUN_SETUP },
346                 { "bundle", cmd_bundle, RUN_SETUP_GENTLY },
347                 { "cat-file", cmd_cat_file, RUN_SETUP },
348                 { "check-attr", cmd_check_attr, RUN_SETUP },
349                 { "check-ignore", cmd_check_ignore, RUN_SETUP | NEED_WORK_TREE },
350                 { "check-mailmap", cmd_check_mailmap, RUN_SETUP },
351                 { "check-ref-format", cmd_check_ref_format },
352                 { "checkout", cmd_checkout, RUN_SETUP | NEED_WORK_TREE },
353                 { "checkout-index", cmd_checkout_index,
354                         RUN_SETUP | NEED_WORK_TREE},
355                 { "cherry", cmd_cherry, RUN_SETUP },
356                 { "cherry-pick", cmd_cherry_pick, RUN_SETUP | NEED_WORK_TREE },
357                 { "clean", cmd_clean, RUN_SETUP | NEED_WORK_TREE },
358                 { "clone", cmd_clone },
359                 { "column", cmd_column, RUN_SETUP_GENTLY },
360                 { "commit", cmd_commit, RUN_SETUP | NEED_WORK_TREE },
361                 { "commit-tree", cmd_commit_tree, RUN_SETUP },
362                 { "config", cmd_config, RUN_SETUP_GENTLY },
363                 { "count-objects", cmd_count_objects, RUN_SETUP },
364                 { "credential", cmd_credential, RUN_SETUP_GENTLY },
365                 { "describe", cmd_describe, RUN_SETUP },
366                 { "diff", cmd_diff },
367                 { "diff-files", cmd_diff_files, RUN_SETUP | NEED_WORK_TREE },
368                 { "diff-index", cmd_diff_index, RUN_SETUP },
369                 { "diff-tree", cmd_diff_tree, RUN_SETUP },
370                 { "fast-export", cmd_fast_export, RUN_SETUP },
371                 { "fetch", cmd_fetch, RUN_SETUP },
372                 { "fetch-pack", cmd_fetch_pack, RUN_SETUP },
373                 { "fmt-merge-msg", cmd_fmt_merge_msg, RUN_SETUP },
374                 { "for-each-ref", cmd_for_each_ref, RUN_SETUP },
375                 { "format-patch", cmd_format_patch, RUN_SETUP },
376                 { "fsck", cmd_fsck, RUN_SETUP },
377                 { "fsck-objects", cmd_fsck, RUN_SETUP },
378                 { "gc", cmd_gc, RUN_SETUP },
379                 { "get-tar-commit-id", cmd_get_tar_commit_id },
380                 { "grep", cmd_grep, RUN_SETUP_GENTLY },
381                 { "hash-object", cmd_hash_object },
382                 { "help", cmd_help },
383                 { "index-pack", cmd_index_pack, RUN_SETUP_GENTLY },
384                 { "init", cmd_init_db },
385                 { "init-db", cmd_init_db },
386                 { "log", cmd_log, RUN_SETUP },
387                 { "ls-files", cmd_ls_files, RUN_SETUP },
388                 { "ls-remote", cmd_ls_remote, RUN_SETUP_GENTLY },
389                 { "ls-tree", cmd_ls_tree, RUN_SETUP },
390                 { "mailinfo", cmd_mailinfo },
391                 { "mailsplit", cmd_mailsplit },
392                 { "merge", cmd_merge, RUN_SETUP | NEED_WORK_TREE },
393                 { "merge-base", cmd_merge_base, RUN_SETUP },
394                 { "merge-file", cmd_merge_file, RUN_SETUP_GENTLY },
395                 { "merge-index", cmd_merge_index, RUN_SETUP },
396                 { "merge-ours", cmd_merge_ours, RUN_SETUP },
397                 { "merge-recursive", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE },
398                 { "merge-recursive-ours", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE },
399                 { "merge-recursive-theirs", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE },
400                 { "merge-subtree", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE },
401                 { "merge-tree", cmd_merge_tree, RUN_SETUP },
402                 { "mktag", cmd_mktag, RUN_SETUP },
403                 { "mktree", cmd_mktree, RUN_SETUP },
404                 { "mv", cmd_mv, RUN_SETUP | NEED_WORK_TREE },
405                 { "name-rev", cmd_name_rev, RUN_SETUP },
406                 { "notes", cmd_notes, RUN_SETUP },
407                 { "pack-objects", cmd_pack_objects, RUN_SETUP },
408                 { "pack-redundant", cmd_pack_redundant, RUN_SETUP },
409                 { "pack-refs", cmd_pack_refs, RUN_SETUP },
410                 { "patch-id", cmd_patch_id },
411                 { "pickaxe", cmd_blame, RUN_SETUP },
412                 { "prune", cmd_prune, RUN_SETUP },
413                 { "prune-packed", cmd_prune_packed, RUN_SETUP },
414                 { "push", cmd_push, RUN_SETUP },
415                 { "read-tree", cmd_read_tree, RUN_SETUP },
416                 { "receive-pack", cmd_receive_pack },
417                 { "reflog", cmd_reflog, RUN_SETUP },
418                 { "remote", cmd_remote, RUN_SETUP },
419                 { "remote-ext", cmd_remote_ext },
420                 { "remote-fd", cmd_remote_fd },
421                 { "repack", cmd_repack, RUN_SETUP },
422                 { "replace", cmd_replace, RUN_SETUP },
423                 { "rerere", cmd_rerere, RUN_SETUP },
424                 { "reset", cmd_reset, RUN_SETUP },
425                 { "rev-list", cmd_rev_list, RUN_SETUP },
426                 { "rev-parse", cmd_rev_parse },
427                 { "revert", cmd_revert, RUN_SETUP | NEED_WORK_TREE },
428                 { "rm", cmd_rm, RUN_SETUP },
429                 { "send-pack", cmd_send_pack, RUN_SETUP },
430                 { "shortlog", cmd_shortlog, RUN_SETUP_GENTLY | USE_PAGER },
431                 { "show", cmd_show, RUN_SETUP },
432                 { "show-branch", cmd_show_branch, RUN_SETUP },
433                 { "show-ref", cmd_show_ref, RUN_SETUP },
434                 { "stage", cmd_add, RUN_SETUP | NEED_WORK_TREE },
435                 { "status", cmd_status, RUN_SETUP | NEED_WORK_TREE },
436                 { "stripspace", cmd_stripspace },
437                 { "symbolic-ref", cmd_symbolic_ref, RUN_SETUP },
438                 { "tag", cmd_tag, RUN_SETUP },
439                 { "unpack-file", cmd_unpack_file, RUN_SETUP },
440                 { "unpack-objects", cmd_unpack_objects, RUN_SETUP },
441                 { "update-index", cmd_update_index, RUN_SETUP },
442                 { "update-ref", cmd_update_ref, RUN_SETUP },
443                 { "update-server-info", cmd_update_server_info, RUN_SETUP },
444                 { "upload-archive", cmd_upload_archive },
445                 { "upload-archive--writer", cmd_upload_archive_writer },
446                 { "var", cmd_var, RUN_SETUP_GENTLY },
447                 { "verify-pack", cmd_verify_pack },
448                 { "verify-tag", cmd_verify_tag, RUN_SETUP },
449                 { "version", cmd_version },
450                 { "whatchanged", cmd_whatchanged, RUN_SETUP },
451                 { "write-tree", cmd_write_tree, RUN_SETUP },
452         };
453         int i;
454         static const char ext[] = STRIP_EXTENSION;
455
456         if (sizeof(ext) > 1) {
457                 i = strlen(argv[0]) - strlen(ext);
458                 if (i > 0 && !strcmp(argv[0] + i, ext)) {
459                         char *argv0 = xstrdup(argv[0]);
460                         argv[0] = cmd = argv0;
461                         argv0[i] = '\0';
462                 }
463         }
464
465         /* Turn "git cmd --help" into "git help cmd" */
466         if (argc > 1 && !strcmp(argv[1], "--help")) {
467                 argv[1] = argv[0];
468                 argv[0] = cmd = "help";
469         }
470
471         for (i = 0; i < ARRAY_SIZE(commands); i++) {
472                 struct cmd_struct *p = commands+i;
473                 if (strcmp(p->cmd, cmd))
474                         continue;
475                 exit(run_builtin(p, argc, argv));
476         }
477 }
478
479 static void execv_dashed_external(const char **argv)
480 {
481         struct strbuf cmd = STRBUF_INIT;
482         const char *tmp;
483         int status;
484
485         if (use_pager == -1)
486                 use_pager = check_pager_config(argv[0]);
487         commit_pager_choice();
488
489         strbuf_addf(&cmd, "git-%s", argv[0]);
490
491         /*
492          * argv[0] must be the git command, but the argv array
493          * belongs to the caller, and may be reused in
494          * subsequent loop iterations. Save argv[0] and
495          * restore it on error.
496          */
497         tmp = argv[0];
498         argv[0] = cmd.buf;
499
500         trace_argv_printf(argv, "trace: exec:");
501
502         /*
503          * if we fail because the command is not found, it is
504          * OK to return. Otherwise, we just pass along the status code.
505          */
506         status = run_command_v_opt(argv, RUN_SILENT_EXEC_FAILURE | RUN_CLEAN_ON_EXIT);
507         if (status >= 0 || errno != ENOENT)
508                 exit(status);
509
510         argv[0] = tmp;
511
512         strbuf_release(&cmd);
513 }
514
515 static int run_argv(int *argcp, const char ***argv)
516 {
517         int done_alias = 0;
518
519         while (1) {
520                 /* See if it's an internal command */
521                 handle_internal_command(*argcp, *argv);
522
523                 /* .. then try the external ones */
524                 execv_dashed_external(*argv);
525
526                 /* It could be an alias -- this works around the insanity
527                  * of overriding "git log" with "git show" by having
528                  * alias.log = show
529                  */
530                 if (done_alias || !handle_alias(argcp, argv))
531                         break;
532                 done_alias = 1;
533         }
534
535         return done_alias;
536 }
537
538
539 int main(int argc, char **av)
540 {
541         const char **argv = (const char **) av;
542         const char *cmd;
543
544         startup_info = &git_startup_info;
545
546         cmd = git_extract_argv0_path(argv[0]);
547         if (!cmd)
548                 cmd = "git-help";
549
550         /*
551          * Always open file descriptors 0/1/2 to avoid clobbering files
552          * in die().  It also avoids messing up when the pipes are dup'ed
553          * onto stdin/stdout/stderr in the child processes we spawn.
554          */
555         sanitize_stdfds();
556
557         git_setup_gettext();
558
559         /*
560          * "git-xxxx" is the same as "git xxxx", but we obviously:
561          *
562          *  - cannot take flags in between the "git" and the "xxxx".
563          *  - cannot execute it externally (since it would just do
564          *    the same thing over again)
565          *
566          * So we just directly call the internal command handler, and
567          * die if that one cannot handle it.
568          */
569         if (starts_with(cmd, "git-")) {
570                 cmd += 4;
571                 argv[0] = cmd;
572                 handle_internal_command(argc, argv);
573                 die("cannot handle %s internally", cmd);
574         }
575
576         /* Look for flags.. */
577         argv++;
578         argc--;
579         handle_options(&argv, &argc, NULL);
580         if (argc > 0) {
581                 if (starts_with(argv[0], "--"))
582                         argv[0] += 2;
583         } else {
584                 /* The user didn't specify a command; give them help */
585                 commit_pager_choice();
586                 printf("usage: %s\n\n", git_usage_string);
587                 list_common_cmds_help();
588                 printf("\n%s\n", _(git_more_info_string));
589                 exit(1);
590         }
591         cmd = argv[0];
592
593         /*
594          * We use PATH to find git commands, but we prepend some higher
595          * precedence paths: the "--exec-path" option, the GIT_EXEC_PATH
596          * environment, and the $(gitexecdir) from the Makefile at build
597          * time.
598          */
599         setup_path();
600
601         while (1) {
602                 static int done_help = 0;
603                 static int was_alias = 0;
604                 was_alias = run_argv(&argc, &argv);
605                 if (errno != ENOENT)
606                         break;
607                 if (was_alias) {
608                         fprintf(stderr, "Expansion of alias '%s' failed; "
609                                 "'%s' is not a git command\n",
610                                 cmd, argv[0]);
611                         exit(1);
612                 }
613                 if (!done_help) {
614                         cmd = argv[0] = help_unknown_cmd(cmd);
615                         done_help = 1;
616                 } else
617                         break;
618         }
619
620         fprintf(stderr, "Failed to run command '%s': %s\n",
621                 cmd, strerror(errno));
622
623         return 1;
624 }