git/builtin-read-tree.c
Junio C Hamano ca885a4fe6 read-tree() and unpack_trees(): use consistent limit
read-tree -m can read up to MAX_TREES, which was arbitrarily set to 8 since
August 2007 (4 is needed to deal with 2 merge-base case).

However, the updated unpack_trees() code had an advertised limit of 4
(which it enforced).  In reality the code was prepared to take only 3
trees and giving 4 caused it to stomp on its stack.  Rename the MAX_TREES
constant to MAX_UNPACK_TREES, move it to the unpack-trees.h common header
file, and use it from both places to avoid future confusion.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-03-13 23:56:36 -07:00

271 lines
6.3 KiB
C

/*
* GIT - The information manager from hell
*
* Copyright (C) Linus Torvalds, 2005
*/
#include "cache.h"
#include "object.h"
#include "tree.h"
#include "tree-walk.h"
#include "cache-tree.h"
#include "unpack-trees.h"
#include "dir.h"
#include "builtin.h"
static int nr_trees;
static struct tree *trees[MAX_UNPACK_TREES];
static int list_tree(unsigned char *sha1)
{
struct tree *tree;
if (nr_trees >= MAX_UNPACK_TREES)
die("I cannot read more than %d trees", MAX_UNPACK_TREES);
tree = parse_tree_indirect(sha1);
if (!tree)
return -1;
trees[nr_trees++] = tree;
return 0;
}
static int read_cache_unmerged(void)
{
int i;
struct cache_entry **dst;
struct cache_entry *last = NULL;
read_cache();
dst = active_cache;
for (i = 0; i < active_nr; i++) {
struct cache_entry *ce = active_cache[i];
if (ce_stage(ce)) {
remove_index_entry(ce);
if (last && !strcmp(ce->name, last->name))
continue;
cache_tree_invalidate_path(active_cache_tree, ce->name);
last = ce;
continue;
}
*dst++ = ce;
}
active_nr = dst - active_cache;
return !!last;
}
static void prime_cache_tree_rec(struct cache_tree *it, struct tree *tree)
{
struct tree_desc desc;
struct name_entry entry;
int cnt;
hashcpy(it->sha1, tree->object.sha1);
init_tree_desc(&desc, tree->buffer, tree->size);
cnt = 0;
while (tree_entry(&desc, &entry)) {
if (!S_ISDIR(entry.mode))
cnt++;
else {
struct cache_tree_sub *sub;
struct tree *subtree = lookup_tree(entry.sha1);
if (!subtree->object.parsed)
parse_tree(subtree);
sub = cache_tree_sub(it, entry.path);
sub->cache_tree = cache_tree();
prime_cache_tree_rec(sub->cache_tree, subtree);
cnt += sub->cache_tree->entry_count;
}
}
it->entry_count = cnt;
}
static void prime_cache_tree(void)
{
if (!nr_trees)
return;
active_cache_tree = cache_tree();
prime_cache_tree_rec(active_cache_tree, trees[0]);
}
static const char read_tree_usage[] = "git-read-tree (<sha> | [[-m [--trivial] [--aggressive] | --reset | --prefix=<prefix>] [-u | -i]] [--exclude-per-directory=<gitignore>] [--index-output=<file>] <sha1> [<sha2> [<sha3>]])";
static struct lock_file lock_file;
int cmd_read_tree(int argc, const char **argv, const char *unused_prefix)
{
int i, newfd, stage = 0;
unsigned char sha1[20];
struct tree_desc t[MAX_UNPACK_TREES];
struct unpack_trees_options opts;
memset(&opts, 0, sizeof(opts));
opts.head_idx = -1;
opts.src_index = &the_index;
opts.dst_index = &the_index;
git_config(git_default_config);
newfd = hold_locked_index(&lock_file, 1);
git_config(git_default_config);
for (i = 1; i < argc; i++) {
const char *arg = argv[i];
/* "-u" means "update", meaning that a merge will update
* the working tree.
*/
if (!strcmp(arg, "-u")) {
opts.update = 1;
continue;
}
if (!strcmp(arg, "-v")) {
opts.verbose_update = 1;
continue;
}
/* "-i" means "index only", meaning that a merge will
* not even look at the working tree.
*/
if (!strcmp(arg, "-i")) {
opts.index_only = 1;
continue;
}
if (!prefixcmp(arg, "--index-output=")) {
set_alternate_index_output(arg + 15);
continue;
}
/* "--prefix=<subdirectory>/" means keep the current index
* entries and put the entries from the tree under the
* given subdirectory.
*/
if (!prefixcmp(arg, "--prefix=")) {
if (stage || opts.merge || opts.prefix)
usage(read_tree_usage);
opts.prefix = arg + 9;
opts.merge = 1;
stage = 1;
if (read_cache_unmerged())
die("you need to resolve your current index first");
continue;
}
/* This differs from "-m" in that we'll silently ignore
* unmerged entries and overwrite working tree files that
* correspond to them.
*/
if (!strcmp(arg, "--reset")) {
if (stage || opts.merge || opts.prefix)
usage(read_tree_usage);
opts.reset = 1;
opts.merge = 1;
stage = 1;
read_cache_unmerged();
continue;
}
if (!strcmp(arg, "--trivial")) {
opts.trivial_merges_only = 1;
continue;
}
if (!strcmp(arg, "--aggressive")) {
opts.aggressive = 1;
continue;
}
/* "-m" stands for "merge", meaning we start in stage 1 */
if (!strcmp(arg, "-m")) {
if (stage || opts.merge || opts.prefix)
usage(read_tree_usage);
if (read_cache_unmerged())
die("you need to resolve your current index first");
stage = 1;
opts.merge = 1;
continue;
}
if (!prefixcmp(arg, "--exclude-per-directory=")) {
struct dir_struct *dir;
if (opts.dir)
die("more than one --exclude-per-directory are given.");
dir = xcalloc(1, sizeof(*opts.dir));
dir->show_ignored = 1;
dir->exclude_per_dir = arg + 24;
opts.dir = dir;
/* We do not need to nor want to do read-directory
* here; we are merely interested in reusing the
* per directory ignore stack mechanism.
*/
continue;
}
/* using -u and -i at the same time makes no sense */
if (1 < opts.index_only + opts.update)
usage(read_tree_usage);
if (get_sha1(arg, sha1))
die("Not a valid object name %s", arg);
if (list_tree(sha1) < 0)
die("failed to unpack tree object %s", arg);
stage++;
}
if ((opts.update||opts.index_only) && !opts.merge)
usage(read_tree_usage);
if ((opts.dir && !opts.update))
die("--exclude-per-directory is meaningless unless -u");
if (opts.merge) {
if (stage < 2)
die("just how do you expect me to merge %d trees?", stage-1);
switch (stage - 1) {
case 1:
opts.fn = opts.prefix ? bind_merge : oneway_merge;
break;
case 2:
opts.fn = twoway_merge;
break;
case 3:
default:
opts.fn = threeway_merge;
cache_tree_free(&active_cache_tree);
break;
}
if (stage - 1 >= 3)
opts.head_idx = stage - 2;
else
opts.head_idx = 1;
}
for (i = 0; i < nr_trees; i++) {
struct tree *tree = trees[i];
parse_tree(tree);
init_tree_desc(t+i, tree->buffer, tree->size);
}
if (unpack_trees(nr_trees, t, &opts))
return 128;
/*
* When reading only one tree (either the most basic form,
* "-m ent" or "--reset ent" form), we can obtain a fully
* valid cache-tree because the index must match exactly
* what came from the tree.
*/
if (nr_trees && !opts.prefix && (!opts.merge || (stage == 2))) {
cache_tree_free(&active_cache_tree);
prime_cache_tree();
}
if (write_cache(newfd, active_cache, active_nr) ||
commit_locked_index(&lock_file))
die("unable to write new index file");
return 0;
}