Re: Segmentation fault in git read-tree
- From
Junio C Hamano <gitster@pobox.com>
- Date
- Mar 14, 2008, 05:07 UTC
- Message-ID
- <7vskytuc55.fsf@gitster.siamese.dyndns.org>
- In-Reply-To
- <7vejadvrk7.fsf@gitster.siamese.dyndns.org>
Thanks for the fix.
Let's do this right, as the two limits should be in sync.
-- >8 -- 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.
Bug-reintroduced-and-fixed-by: Linus Torvalds <torvalds@linux-foundation.org> Patch-munged-and-tested-by: Junio C Hamano <gitster@pobox.com> --- builtin-read-tree.c | 9 ++++----- unpack-trees.c | 6 +++--- unpack-trees.h | 2 ++ 3 files changed, 9 insertions(+), 8 deletions(-)
diff --git a/builtin-read-tree.c b/builtin-read-tree.c index 160456d..e9cfd2b 100644 --- a/builtin-read-tree.c +++ b/builtin-read-tree.c @@ -13,16 +13,15 @@ #include "dir.h" #include "builtin.h" -#define MAX_TREES 8 static int nr_trees; -static struct tree *trees[MAX_TREES]; +static struct tree *trees[MAX_UNPACK_TREES]; static int list_tree(unsigned char *sha1) { struct tree *tree; - if (nr_trees >= MAX_TREES) - die("I cannot read more than %d trees", MAX_TREES); + 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; @@ -97,7 +96,7 @@ 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_TREES]; + struct tree_desc t[MAX_UNPACK_TREES]; struct unpack_trees_options opts; memset(&opts, 0, sizeof(opts)); diff --git a/unpack-trees.c b/unpack-trees.c index be89d52..91649f3 100644 --- a/unpack-trees.c +++ b/unpack-trees.c @@ -123,7 +123,7 @@ static int unpack_index_entry(struct cache_entry *ce, struct unpack_trees_option int traverse_trees_recursive(int n, unsigned long dirmask, unsigned long df_conflicts, struct name_entry *names, struct traverse_info *info) { int i; - struct tree_desc t[3]; + struct tree_desc t[MAX_UNPACK_TREES]; struct traverse_info newinfo; struct name_entry *p; @@ -327,8 +327,8 @@ int unpack_trees(unsigned len, struct tree_desc *t, struct unpack_trees_options { static struct cache_entry *dfc; - if (len > 4) - die("unpack_trees takes at most four trees"); + if (len > MAX_UNPACK_TREES) + die("unpack_trees takes at most %d trees", MAX_UNPACK_TREES); memset(&state, 0, sizeof(state)); state.base_dir = ""; state.force = 1; diff --git a/unpack-trees.h b/unpack-trees.h index e8abbcd..50453ed 100644 --- a/unpack-trees.h +++ b/unpack-trees.h @@ -1,6 +1,8 @@ #ifndef UNPACK_TREES_H #define UNPACK_TREES_H +#define MAX_UNPACK_TREES 8 + struct unpack_trees_options; typedef int (*merge_fn_t)(struct cache_entry **src,