Fix potentially dangerous uses of mkpath and git_path
[git/jnareb-git.git] / builtin-checkout.c
blob57b94d282931187a0cb6394d4df707237038a7eb
1 #include "cache.h"
2 #include "builtin.h"
3 #include "parse-options.h"
4 #include "refs.h"
5 #include "commit.h"
6 #include "tree.h"
7 #include "tree-walk.h"
8 #include "unpack-trees.h"
9 #include "dir.h"
10 #include "run-command.h"
11 #include "merge-recursive.h"
12 #include "branch.h"
13 #include "diff.h"
14 #include "revision.h"
15 #include "remote.h"
16 #include "blob.h"
17 #include "xdiff-interface.h"
18 #include "ll-merge.h"
20 static const char * const checkout_usage[] = {
21 "git checkout [options] <branch>",
22 "git checkout [options] [<branch>] -- <file>...",
23 NULL,
26 struct checkout_opts {
27 int quiet;
28 int merge;
29 int force;
30 int writeout_stage;
31 int writeout_error;
33 const char *new_branch;
34 int new_branch_log;
35 enum branch_track track;
38 static int post_checkout_hook(struct commit *old, struct commit *new,
39 int changed)
41 struct child_process proc;
42 const char *name = git_path("hooks/post-checkout");
43 const char *argv[5];
45 if (access(name, X_OK) < 0)
46 return 0;
48 memset(&proc, 0, sizeof(proc));
49 argv[0] = name;
50 argv[1] = xstrdup(sha1_to_hex(old->object.sha1));
51 argv[2] = xstrdup(sha1_to_hex(new->object.sha1));
52 argv[3] = changed ? "1" : "0";
53 argv[4] = NULL;
54 proc.argv = argv;
55 proc.no_stdin = 1;
56 proc.stdout_to_stderr = 1;
57 return run_command(&proc);
60 static int update_some(const unsigned char *sha1, const char *base, int baselen,
61 const char *pathname, unsigned mode, int stage, void *context)
63 int len;
64 struct cache_entry *ce;
66 if (S_ISGITLINK(mode))
67 return 0;
69 if (S_ISDIR(mode))
70 return READ_TREE_RECURSIVE;
72 len = baselen + strlen(pathname);
73 ce = xcalloc(1, cache_entry_size(len));
74 hashcpy(ce->sha1, sha1);
75 memcpy(ce->name, base, baselen);
76 memcpy(ce->name + baselen, pathname, len - baselen);
77 ce->ce_flags = create_ce_flags(len, 0);
78 ce->ce_mode = create_ce_mode(mode);
79 add_cache_entry(ce, ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE);
80 return 0;
83 static int read_tree_some(struct tree *tree, const char **pathspec)
85 read_tree_recursive(tree, "", 0, 0, pathspec, update_some, NULL);
87 /* update the index with the given tree's info
88 * for all args, expanding wildcards, and exit
89 * with any non-zero return code.
91 return 0;
94 static int skip_same_name(struct cache_entry *ce, int pos)
96 while (++pos < active_nr &&
97 !strcmp(active_cache[pos]->name, ce->name))
98 ; /* skip */
99 return pos;
102 static int check_stage(int stage, struct cache_entry *ce, int pos)
104 while (pos < active_nr &&
105 !strcmp(active_cache[pos]->name, ce->name)) {
106 if (ce_stage(active_cache[pos]) == stage)
107 return 0;
108 pos++;
110 return error("path '%s' does not have %s version",
111 ce->name,
112 (stage == 2) ? "our" : "their");
115 static int check_all_stages(struct cache_entry *ce, int pos)
117 if (ce_stage(ce) != 1 ||
118 active_nr <= pos + 2 ||
119 strcmp(active_cache[pos+1]->name, ce->name) ||
120 ce_stage(active_cache[pos+1]) != 2 ||
121 strcmp(active_cache[pos+2]->name, ce->name) ||
122 ce_stage(active_cache[pos+2]) != 3)
123 return error("path '%s' does not have all three versions",
124 ce->name);
125 return 0;
128 static int checkout_stage(int stage, struct cache_entry *ce, int pos,
129 struct checkout *state)
131 while (pos < active_nr &&
132 !strcmp(active_cache[pos]->name, ce->name)) {
133 if (ce_stage(active_cache[pos]) == stage)
134 return checkout_entry(active_cache[pos], state, NULL);
135 pos++;
137 return error("path '%s' does not have %s version",
138 ce->name,
139 (stage == 2) ? "our" : "their");
142 /* NEEDSWORK: share with merge-recursive */
143 static void fill_mm(const unsigned char *sha1, mmfile_t *mm)
145 unsigned long size;
146 enum object_type type;
148 if (!hashcmp(sha1, null_sha1)) {
149 mm->ptr = xstrdup("");
150 mm->size = 0;
151 return;
154 mm->ptr = read_sha1_file(sha1, &type, &size);
155 if (!mm->ptr || type != OBJ_BLOB)
156 die("unable to read blob object %s", sha1_to_hex(sha1));
157 mm->size = size;
160 static int checkout_merged(int pos, struct checkout *state)
162 struct cache_entry *ce = active_cache[pos];
163 const char *path = ce->name;
164 mmfile_t ancestor, ours, theirs;
165 int status;
166 unsigned char sha1[20];
167 mmbuffer_t result_buf;
169 if (ce_stage(ce) != 1 ||
170 active_nr <= pos + 2 ||
171 strcmp(active_cache[pos+1]->name, path) ||
172 ce_stage(active_cache[pos+1]) != 2 ||
173 strcmp(active_cache[pos+2]->name, path) ||
174 ce_stage(active_cache[pos+2]) != 3)
175 return error("path '%s' does not have all 3 versions", path);
177 fill_mm(active_cache[pos]->sha1, &ancestor);
178 fill_mm(active_cache[pos+1]->sha1, &ours);
179 fill_mm(active_cache[pos+2]->sha1, &theirs);
181 status = ll_merge(&result_buf, path, &ancestor,
182 &ours, "ours", &theirs, "theirs", 1);
183 free(ancestor.ptr);
184 free(ours.ptr);
185 free(theirs.ptr);
186 if (status < 0 || !result_buf.ptr) {
187 free(result_buf.ptr);
188 return error("path '%s': cannot merge", path);
192 * NEEDSWORK:
193 * There is absolutely no reason to write this as a blob object
194 * and create a phoney cache entry just to leak. This hack is
195 * primarily to get to the write_entry() machinery that massages
196 * the contents to work-tree format and writes out which only
197 * allows it for a cache entry. The code in write_entry() needs
198 * to be refactored to allow us to feed a <buffer, size, mode>
199 * instead of a cache entry. Such a refactoring would help
200 * merge_recursive as well (it also writes the merge result to the
201 * object database even when it may contain conflicts).
203 if (write_sha1_file(result_buf.ptr, result_buf.size,
204 blob_type, sha1))
205 die("Unable to add merge result for '%s'", path);
206 ce = make_cache_entry(create_ce_mode(active_cache[pos+1]->ce_mode),
207 sha1,
208 path, 2, 0);
209 if (!ce)
210 die("make_cache_entry failed for path '%s'", path);
211 status = checkout_entry(ce, state, NULL);
212 return status;
215 static int checkout_paths(struct tree *source_tree, const char **pathspec,
216 struct checkout_opts *opts)
218 int pos;
219 struct checkout state;
220 static char *ps_matched;
221 unsigned char rev[20];
222 int flag;
223 struct commit *head;
224 int errs = 0;
225 int stage = opts->writeout_stage;
226 int merge = opts->merge;
227 int newfd;
228 struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
230 newfd = hold_locked_index(lock_file, 1);
231 read_cache();
233 if (source_tree)
234 read_tree_some(source_tree, pathspec);
236 for (pos = 0; pathspec[pos]; pos++)
238 ps_matched = xcalloc(1, pos);
240 for (pos = 0; pos < active_nr; pos++) {
241 struct cache_entry *ce = active_cache[pos];
242 pathspec_match(pathspec, ps_matched, ce->name, 0);
245 if (report_path_error(ps_matched, pathspec, 0))
246 return 1;
248 /* Any unmerged paths? */
249 for (pos = 0; pos < active_nr; pos++) {
250 struct cache_entry *ce = active_cache[pos];
251 if (pathspec_match(pathspec, NULL, ce->name, 0)) {
252 if (!ce_stage(ce))
253 continue;
254 if (opts->force) {
255 warning("path '%s' is unmerged", ce->name);
256 } else if (stage) {
257 errs |= check_stage(stage, ce, pos);
258 } else if (opts->merge) {
259 errs |= check_all_stages(ce, pos);
260 } else {
261 errs = 1;
262 error("path '%s' is unmerged", ce->name);
264 pos = skip_same_name(ce, pos) - 1;
267 if (errs)
268 return 1;
270 /* Now we are committed to check them out */
271 memset(&state, 0, sizeof(state));
272 state.force = 1;
273 state.refresh_cache = 1;
274 for (pos = 0; pos < active_nr; pos++) {
275 struct cache_entry *ce = active_cache[pos];
276 if (pathspec_match(pathspec, NULL, ce->name, 0)) {
277 if (!ce_stage(ce)) {
278 errs |= checkout_entry(ce, &state, NULL);
279 continue;
281 if (stage)
282 errs |= checkout_stage(stage, ce, pos, &state);
283 else if (merge)
284 errs |= checkout_merged(pos, &state);
285 pos = skip_same_name(ce, pos) - 1;
289 if (write_cache(newfd, active_cache, active_nr) ||
290 commit_locked_index(lock_file))
291 die("unable to write new index file");
293 resolve_ref("HEAD", rev, 0, &flag);
294 head = lookup_commit_reference_gently(rev, 1);
296 errs |= post_checkout_hook(head, head, 0);
297 return errs;
300 static void show_local_changes(struct object *head)
302 struct rev_info rev;
303 /* I think we want full paths, even if we're in a subdirectory. */
304 init_revisions(&rev, NULL);
305 rev.abbrev = 0;
306 rev.diffopt.output_format |= DIFF_FORMAT_NAME_STATUS;
307 add_pending_object(&rev, head, NULL);
308 run_diff_index(&rev, 0);
311 static void describe_detached_head(char *msg, struct commit *commit)
313 struct strbuf sb = STRBUF_INIT;
314 parse_commit(commit);
315 pretty_print_commit(CMIT_FMT_ONELINE, commit, &sb, 0, NULL, NULL, 0, 0);
316 fprintf(stderr, "%s %s... %s\n", msg,
317 find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV), sb.buf);
318 strbuf_release(&sb);
321 static int reset_tree(struct tree *tree, struct checkout_opts *o, int worktree)
323 struct unpack_trees_options opts;
324 struct tree_desc tree_desc;
326 memset(&opts, 0, sizeof(opts));
327 opts.head_idx = -1;
328 opts.update = worktree;
329 opts.skip_unmerged = !worktree;
330 opts.reset = 1;
331 opts.merge = 1;
332 opts.fn = oneway_merge;
333 opts.verbose_update = !o->quiet;
334 opts.src_index = &the_index;
335 opts.dst_index = &the_index;
336 parse_tree(tree);
337 init_tree_desc(&tree_desc, tree->buffer, tree->size);
338 switch (unpack_trees(1, &tree_desc, &opts)) {
339 case -2:
340 o->writeout_error = 1;
342 * We return 0 nevertheless, as the index is all right
343 * and more importantly we have made best efforts to
344 * update paths in the work tree, and we cannot revert
345 * them.
347 case 0:
348 return 0;
349 default:
350 return 128;
354 struct branch_info {
355 const char *name; /* The short name used */
356 const char *path; /* The full name of a real branch */
357 struct commit *commit; /* The named commit */
360 static void setup_branch_path(struct branch_info *branch)
362 struct strbuf buf = STRBUF_INIT;
363 strbuf_addstr(&buf, "refs/heads/");
364 strbuf_addstr(&buf, branch->name);
365 branch->path = strbuf_detach(&buf, NULL);
368 static int merge_working_tree(struct checkout_opts *opts,
369 struct branch_info *old, struct branch_info *new)
371 int ret;
372 struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
373 int newfd = hold_locked_index(lock_file, 1);
374 read_cache();
376 if (opts->force) {
377 ret = reset_tree(new->commit->tree, opts, 1);
378 if (ret)
379 return ret;
380 } else {
381 struct tree_desc trees[2];
382 struct tree *tree;
383 struct unpack_trees_options topts;
385 memset(&topts, 0, sizeof(topts));
386 topts.head_idx = -1;
387 topts.src_index = &the_index;
388 topts.dst_index = &the_index;
390 topts.msgs.not_uptodate_file = "You have local changes to '%s'; cannot switch branches.";
392 refresh_cache(REFRESH_QUIET);
394 if (unmerged_cache()) {
395 error("you need to resolve your current index first");
396 return 1;
399 /* 2-way merge to the new branch */
400 topts.initial_checkout = (!active_nr &&
401 (old->commit == new->commit));
402 topts.update = 1;
403 topts.merge = 1;
404 topts.gently = opts->merge;
405 topts.verbose_update = !opts->quiet;
406 topts.fn = twoway_merge;
407 topts.dir = xcalloc(1, sizeof(*topts.dir));
408 topts.dir->show_ignored = 1;
409 topts.dir->exclude_per_dir = ".gitignore";
410 tree = parse_tree_indirect(old->commit->object.sha1);
411 init_tree_desc(&trees[0], tree->buffer, tree->size);
412 tree = parse_tree_indirect(new->commit->object.sha1);
413 init_tree_desc(&trees[1], tree->buffer, tree->size);
415 ret = unpack_trees(2, trees, &topts);
416 if (ret == -1) {
418 * Unpack couldn't do a trivial merge; either
419 * give up or do a real merge, depending on
420 * whether the merge flag was used.
422 struct tree *result;
423 struct tree *work;
424 struct merge_options o;
425 if (!opts->merge)
426 return 1;
427 parse_commit(old->commit);
429 /* Do more real merge */
432 * We update the index fully, then write the
433 * tree from the index, then merge the new
434 * branch with the current tree, with the old
435 * branch as the base. Then we reset the index
436 * (but not the working tree) to the new
437 * branch, leaving the working tree as the
438 * merged version, but skipping unmerged
439 * entries in the index.
442 add_files_to_cache(NULL, NULL, 0);
443 init_merge_options(&o);
444 o.verbosity = 0;
445 work = write_tree_from_memory(&o);
447 ret = reset_tree(new->commit->tree, opts, 1);
448 if (ret)
449 return ret;
450 o.branch1 = new->name;
451 o.branch2 = "local";
452 merge_trees(&o, new->commit->tree, work,
453 old->commit->tree, &result);
454 ret = reset_tree(new->commit->tree, opts, 0);
455 if (ret)
456 return ret;
460 if (write_cache(newfd, active_cache, active_nr) ||
461 commit_locked_index(lock_file))
462 die("unable to write new index file");
464 if (!opts->force && !opts->quiet)
465 show_local_changes(&new->commit->object);
467 return 0;
470 static void report_tracking(struct branch_info *new)
472 struct strbuf sb = STRBUF_INIT;
473 struct branch *branch = branch_get(new->name);
475 if (!format_tracking_info(branch, &sb))
476 return;
477 fputs(sb.buf, stdout);
478 strbuf_release(&sb);
481 static void update_refs_for_switch(struct checkout_opts *opts,
482 struct branch_info *old,
483 struct branch_info *new)
485 struct strbuf msg = STRBUF_INIT;
486 const char *old_desc;
487 if (opts->new_branch) {
488 create_branch(old->name, opts->new_branch, new->name, 0,
489 opts->new_branch_log, opts->track);
490 new->name = opts->new_branch;
491 setup_branch_path(new);
494 old_desc = old->name;
495 if (!old_desc)
496 old_desc = sha1_to_hex(old->commit->object.sha1);
497 strbuf_addf(&msg, "checkout: moving from %s to %s",
498 old_desc, new->name);
500 if (new->path) {
501 create_symref("HEAD", new->path, msg.buf);
502 if (!opts->quiet) {
503 if (old->path && !strcmp(new->path, old->path))
504 fprintf(stderr, "Already on \"%s\"\n",
505 new->name);
506 else
507 fprintf(stderr, "Switched to%s branch \"%s\"\n",
508 opts->new_branch ? " a new" : "",
509 new->name);
511 } else if (strcmp(new->name, "HEAD")) {
512 update_ref(msg.buf, "HEAD", new->commit->object.sha1, NULL,
513 REF_NODEREF, DIE_ON_ERR);
514 if (!opts->quiet) {
515 if (old->path)
516 fprintf(stderr, "Note: moving to \"%s\" which isn't a local branch\nIf you want to create a new branch from this checkout, you may do so\n(now or later) by using -b with the checkout command again. Example:\n git checkout -b <new_branch_name>\n", new->name);
517 describe_detached_head("HEAD is now at", new->commit);
520 remove_branch_state();
521 strbuf_release(&msg);
522 if (!opts->quiet && (new->path || !strcmp(new->name, "HEAD")))
523 report_tracking(new);
526 static int switch_branches(struct checkout_opts *opts, struct branch_info *new)
528 int ret = 0;
529 struct branch_info old;
530 unsigned char rev[20];
531 int flag;
532 memset(&old, 0, sizeof(old));
533 old.path = resolve_ref("HEAD", rev, 0, &flag);
534 old.commit = lookup_commit_reference_gently(rev, 1);
535 if (!(flag & REF_ISSYMREF))
536 old.path = NULL;
538 if (old.path && !prefixcmp(old.path, "refs/heads/"))
539 old.name = old.path + strlen("refs/heads/");
541 if (!new->name) {
542 new->name = "HEAD";
543 new->commit = old.commit;
544 if (!new->commit)
545 die("You are on a branch yet to be born");
546 parse_commit(new->commit);
550 * If we were on a detached HEAD, but we are now moving to
551 * a new commit, we want to mention the old commit once more
552 * to remind the user that it might be lost.
554 if (!opts->quiet && !old.path && new->commit != old.commit)
555 describe_detached_head("Previous HEAD position was", old.commit);
557 if (!old.commit) {
558 if (!opts->quiet) {
559 fprintf(stderr, "warning: You appear to be on a branch yet to be born.\n");
560 fprintf(stderr, "warning: Forcing checkout of %s.\n", new->name);
562 opts->force = 1;
565 ret = merge_working_tree(opts, &old, new);
566 if (ret)
567 return ret;
569 update_refs_for_switch(opts, &old, new);
571 ret = post_checkout_hook(old.commit, new->commit, 1);
572 return ret || opts->writeout_error;
575 static int git_checkout_config(const char *var, const char *value, void *cb)
577 return git_xmerge_config(var, value, cb);
580 int cmd_checkout(int argc, const char **argv, const char *prefix)
582 struct checkout_opts opts;
583 unsigned char rev[20];
584 const char *arg;
585 struct branch_info new;
586 struct tree *source_tree = NULL;
587 char *conflict_style = NULL;
588 struct option options[] = {
589 OPT__QUIET(&opts.quiet),
590 OPT_STRING('b', NULL, &opts.new_branch, "new branch", "branch"),
591 OPT_BOOLEAN('l', NULL, &opts.new_branch_log, "log for new branch"),
592 OPT_SET_INT('t', "track", &opts.track, "track",
593 BRANCH_TRACK_EXPLICIT),
594 OPT_SET_INT('2', "ours", &opts.writeout_stage, "stage",
596 OPT_SET_INT('3', "theirs", &opts.writeout_stage, "stage",
598 OPT_BOOLEAN('f', NULL, &opts.force, "force"),
599 OPT_BOOLEAN('m', "merge", &opts.merge, "merge"),
600 OPT_STRING(0, "conflict", &conflict_style, "style",
601 "conflict style (merge or diff3)"),
602 OPT_END(),
604 int has_dash_dash;
606 memset(&opts, 0, sizeof(opts));
607 memset(&new, 0, sizeof(new));
609 git_config(git_checkout_config, NULL);
611 opts.track = BRANCH_TRACK_UNSPECIFIED;
613 argc = parse_options(argc, argv, options, checkout_usage,
614 PARSE_OPT_KEEP_DASHDASH);
616 /* --track without -b should DWIM */
617 if (0 < opts.track && !opts.new_branch) {
618 const char *argv0 = argv[0];
619 if (!argc || !strcmp(argv0, "--"))
620 die ("--track needs a branch name");
621 if (!prefixcmp(argv0, "refs/"))
622 argv0 += 5;
623 if (!prefixcmp(argv0, "remotes/"))
624 argv0 += 8;
625 argv0 = strchr(argv0, '/');
626 if (!argv0 || !argv0[1])
627 die ("Missing branch name; try -b");
628 opts.new_branch = argv0 + 1;
631 if (opts.track == BRANCH_TRACK_UNSPECIFIED)
632 opts.track = git_branch_track;
633 if (conflict_style) {
634 opts.merge = 1; /* implied */
635 git_xmerge_config("merge.conflictstyle", conflict_style, NULL);
638 if (opts.force && opts.merge)
639 die("git checkout: -f and -m are incompatible");
642 * case 1: git checkout <ref> -- [<paths>]
644 * <ref> must be a valid tree, everything after the '--' must be
645 * a path.
647 * case 2: git checkout -- [<paths>]
649 * everything after the '--' must be paths.
651 * case 3: git checkout <something> [<paths>]
653 * With no paths, if <something> is a commit, that is to
654 * switch to the branch or detach HEAD at it.
656 * Otherwise <something> shall not be ambiguous.
657 * - If it's *only* a reference, treat it like case (1).
658 * - If it's only a path, treat it like case (2).
659 * - else: fail.
662 if (argc) {
663 if (!strcmp(argv[0], "--")) { /* case (2) */
664 argv++;
665 argc--;
666 goto no_reference;
669 arg = argv[0];
670 has_dash_dash = (argc > 1) && !strcmp(argv[1], "--");
672 if (get_sha1(arg, rev)) {
673 if (has_dash_dash) /* case (1) */
674 die("invalid reference: %s", arg);
675 goto no_reference; /* case (3 -> 2) */
678 /* we can't end up being in (2) anymore, eat the argument */
679 argv++;
680 argc--;
682 if ((new.commit = lookup_commit_reference_gently(rev, 1))) {
683 new.name = arg;
684 setup_branch_path(&new);
685 if (resolve_ref(new.path, rev, 1, NULL))
686 new.commit = lookup_commit_reference(rev);
687 else
688 new.path = NULL;
689 parse_commit(new.commit);
690 source_tree = new.commit->tree;
691 } else
692 source_tree = parse_tree_indirect(rev);
694 if (!source_tree) /* case (1): want a tree */
695 die("reference is not a tree: %s", arg);
696 if (!has_dash_dash) {/* case (3 -> 1) */
698 * Do not complain the most common case
699 * git checkout branch
700 * even if there happen to be a file called 'branch';
701 * it would be extremely annoying.
703 if (argc)
704 verify_non_filename(NULL, arg);
706 else {
707 argv++;
708 argc--;
712 no_reference:
713 if (argc) {
714 const char **pathspec = get_pathspec(prefix, argv);
716 if (!pathspec)
717 die("invalid path specification");
719 /* Checkout paths */
720 if (opts.new_branch) {
721 if (argc == 1) {
722 die("git checkout: updating paths is incompatible with switching branches.\nDid you intend to checkout '%s' which can not be resolved as commit?", argv[0]);
723 } else {
724 die("git checkout: updating paths is incompatible with switching branches.");
728 if (1 < !!opts.writeout_stage + !!opts.force + !!opts.merge)
729 die("git checkout: --ours/--theirs, --force and --merge are incompatible when\nchecking out of the index.");
731 return checkout_paths(source_tree, pathspec, &opts);
734 if (opts.new_branch) {
735 struct strbuf buf = STRBUF_INIT;
736 strbuf_addstr(&buf, "refs/heads/");
737 strbuf_addstr(&buf, opts.new_branch);
738 if (!get_sha1(buf.buf, rev))
739 die("git checkout: branch %s already exists", opts.new_branch);
740 if (check_ref_format(buf.buf))
741 die("git checkout: we do not like '%s' as a branch name.", opts.new_branch);
742 strbuf_release(&buf);
745 if (new.name && !new.commit) {
746 die("Cannot switch branch to a non-commit.");
748 if (opts.writeout_stage)
749 die("--ours/--theirs is incompatible with switching branches.");
751 return switch_branches(&opts, &new);