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>

diff --git a/builtin-read-tree.c b/builtin-read-tree.c
index 160456dad13322e3547d6dc3fc91626bd3ec9c2b..e9cfd2bbc5539ee0c9c048798383b837ff63991b 100644 (file)
--- 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 be89d52e8c55d71fe7dff2e7e2f6d6d5f8a7ca16..91649f31d6e73cac256a272b4e5eba0dc871d8ce 100644 (file)
--- 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 e8abbcd037167a58c816d94f4f0c617d6572d23d..50453ed20f755fea2e7138d7f01300b318f28dce 100644 (file)
--- 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,