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git/tree.h
Jeff King 1ee7a5c388 read_tree(): respect max_allowed_tree_depth
The read_tree() function reads trees recursively (via its read_tree_at()
helper). This can cause it to run out of stack space on very deep trees.
Let's teach it about the new core.maxTreeDepth option.

The easiest way to demonstrate this is via "ls-tree -r", which the test
covers. Note that I needed a tree depth of ~30k to trigger a segfault on
my Linux system, not the 4100 used by our "big" test in t6700. However,
that test still tells us what we want: that the default 4096 limit is
enough to prevent segfaults on all platforms. We could bump it, but that
increases the cost of the test setup for little gain.

As an interesting side-note: when I originally wrote this patch about 4
years ago, I needed a depth of ~50k to segfault. But porting it forward,
the number is much lower. Seemingly little things like cf0983213c (hash:
add an algo member to struct object_id, 2021-04-26) take it from 32,722
to 29,080.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2023-08-31 15:51:08 -07:00

57 lines
1.5 KiB
C

#ifndef TREE_H
#define TREE_H
#include "object.h"
struct pathspec;
struct repository;
struct strbuf;
struct tree {
struct object object;
void *buffer;
unsigned long size;
};
extern const char *tree_type;
struct tree *lookup_tree(struct repository *r, const struct object_id *oid);
int parse_tree_buffer(struct tree *item, void *buffer, unsigned long size);
int parse_tree_gently(struct tree *tree, int quiet_on_missing);
static inline int parse_tree(struct tree *tree)
{
return parse_tree_gently(tree, 0);
}
void free_tree_buffer(struct tree *tree);
/* Parses and returns the tree in the given ent, chasing tags and commits. */
struct tree *parse_tree_indirect(const struct object_id *oid);
/*
* Functions for comparing pathnames
*/
int base_name_compare(const char *name1, size_t len1, int mode1,
const char *name2, size_t len2, int mode2);
int df_name_compare(const char *name1, size_t len1, int mode1,
const char *name2, size_t len2, int mode2);
int name_compare(const char *name1, size_t len1,
const char *name2, size_t len2);
#define READ_TREE_RECURSIVE 1
typedef int (*read_tree_fn_t)(const struct object_id *, struct strbuf *, const char *, unsigned int, void *);
int read_tree_at(struct repository *r,
struct tree *tree, struct strbuf *base,
int depth,
const struct pathspec *pathspec,
read_tree_fn_t fn, void *context);
int read_tree(struct repository *r,
struct tree *tree,
const struct pathspec *pathspec,
read_tree_fn_t fn, void *context);
#endif /* TREE_H */