* [PATCH v4 2/2] fsck: handle bad trees like other errors
2016-09-27 20:59 [PATCH v4 1/2] tree-walk: be more specific about corrupt tree errors David Turner
@ 2016-09-27 20:59 ` David Turner
2016-09-27 21:45 ` [PATCH v4 1/2] tree-walk: be more specific about corrupt tree errors Junio C Hamano
1 sibling, 0 replies; 3+ messages in thread
From: David Turner @ 2016-09-27 20:59 UTC (permalink / raw)
To: git, peff; +Cc: David Turner
Instead of dying when fsck hits a malformed tree object, log the error
like any other and continue. Now fsck can tell the user which tree is
bad, too.
Signed-off-by: David Turner <dturner@twosigma.com>
---
fsck.c | 18 ++++++++-----
t/t1450-fsck.sh | 16 +++++++++--
tree-walk.c | 83 +++++++++++++++++++++++++++++++++++++++++++++++++--------
tree-walk.h | 8 ++++++
4 files changed, 106 insertions(+), 19 deletions(-)
diff --git a/fsck.c b/fsck.c
index c9cf3de..4a3069e 100644
--- a/fsck.c
+++ b/fsck.c
@@ -347,8 +347,9 @@ static int fsck_walk_tree(struct tree *tree, void *data, struct fsck_options *op
return -1;
name = get_object_name(options, &tree->object);
- init_tree_desc(&desc, tree->buffer, tree->size);
- while (tree_entry(&desc, &entry)) {
+ if (init_tree_desc_gently(&desc, tree->buffer, tree->size))
+ return -1;
+ while (tree_entry_gently(&desc, &entry)) {
struct object *obj;
int result;
@@ -520,7 +521,7 @@ static int verify_ordered(unsigned mode1, const char *name1, unsigned mode2, con
static int fsck_tree(struct tree *item, struct fsck_options *options)
{
- int retval;
+ int retval = 0;
int has_null_sha1 = 0;
int has_full_path = 0;
int has_empty_name = 0;
@@ -535,7 +536,10 @@ static int fsck_tree(struct tree *item, struct fsck_options *options)
unsigned o_mode;
const char *o_name;
- init_tree_desc(&desc, item->buffer, item->size);
+ if (init_tree_desc_gently(&desc, item->buffer, item->size)) {
+ retval += report(options, &item->object, FSCK_MSG_BAD_TREE, "cannot be parsed as a tree");
+ return retval;
+ }
o_mode = 0;
o_name = NULL;
@@ -556,7 +560,10 @@ static int fsck_tree(struct tree *item, struct fsck_options *options)
is_hfs_dotgit(name) ||
is_ntfs_dotgit(name));
has_zero_pad |= *(char *)desc.buffer == '0';
- update_tree_entry(&desc);
+ if (update_tree_entry_gently(&desc)) {
+ retval += report(options, &item->object, FSCK_MSG_BAD_TREE, "cannot be parsed as a tree");
+ break;
+ }
switch (mode) {
/*
@@ -597,7 +604,6 @@ static int fsck_tree(struct tree *item, struct fsck_options *options)
o_name = name;
}
- retval = 0;
if (has_null_sha1)
retval += report(options, &item->object, FSCK_MSG_NULL_SHA1, "contains entries pointing to null sha1");
if (has_full_path)
diff --git a/t/t1450-fsck.sh b/t/t1450-fsck.sh
index 8f52da2..ee7d473 100755
--- a/t/t1450-fsck.sh
+++ b/t/t1450-fsck.sh
@@ -188,8 +188,7 @@ test_expect_success 'commit with NUL in header' '
grep "error in commit $new.*unterminated header: NUL at offset" out
'
-test_expect_success 'malformatted tree object' '
- test_when_finished "git update-ref -d refs/tags/wrong" &&
+test_expect_success 'tree object with duplicate entries' '
test_when_finished "remove_object \$T" &&
T=$(
GIT_INDEX_FILE=test-index &&
@@ -208,6 +207,19 @@ test_expect_success 'malformatted tree object' '
grep "error in tree .*contains duplicate file entries" out
'
+test_expect_success 'unparseable tree object' '
+ test_when_finished "git update-ref -d refs/heads/wrong" &&
+ test_when_finished "remove_object \$tree_sha1" &&
+ test_when_finished "remove_object \$commit_sha1" &&
+ tree_sha1=$(printf "100644 \0twenty-bytes-of-junk" | git hash-object -t tree --stdin -w --literally) &&
+ commit_sha1=$(git commit-tree $tree_sha1) &&
+ git update-ref refs/heads/wrong $commit_sha1 &&
+ test_must_fail git fsck 2>out &&
+ test_i18ngrep "error: empty filename in tree entry" out &&
+ test_i18ngrep "$tree_sha1" out &&
+ test_i18ngrep ! "fatal: empty filename in tree entry" out
+'
+
test_expect_success 'tag pointing to nonexistent' '
cat >invalid-tag <<-\EOF &&
object ffffffffffffffffffffffffffffffffffffffff
diff --git a/tree-walk.c b/tree-walk.c
index 24f9a0f..828f435 100644
--- a/tree-walk.c
+++ b/tree-walk.c
@@ -22,33 +22,60 @@ static const char *get_mode(const char *str, unsigned int *modep)
return str;
}
-static void decode_tree_entry(struct tree_desc *desc, const char *buf, unsigned long size)
+static int decode_tree_entry(struct tree_desc *desc, const char *buf, unsigned long size, struct strbuf *err)
{
const char *path;
unsigned int mode, len;
- if (size < 23 || buf[size - 21])
- die(_("too-short tree object"));
+ if (size < 23 || buf[size - 21]) {
+ strbuf_addstr(err, _("too-short tree object"));
+ return -1;
+ }
path = get_mode(buf, &mode);
- if (!path)
- die(_("malformed mode in tree entry for tree"));
- if (!*path)
- die(_("empty filename in tree entry for tree"));
+ if (!path) {
+ strbuf_addstr(err, _("malformed mode in tree entry"));
+ return -1;
+ }
+ if (!*path) {
+ strbuf_addstr(err, _("empty filename in tree entry"));
+ return -1;
+ }
len = strlen(path) + 1;
/* Initialize the descriptor entry */
desc->entry.path = path;
desc->entry.mode = canon_mode(mode);
desc->entry.oid = (const struct object_id *)(path + len);
+
+ return 0;
}
-void init_tree_desc(struct tree_desc *desc, const void *buffer, unsigned long size)
+static int init_tree_desc_internal(struct tree_desc *desc, const void *buffer, unsigned long size, struct strbuf *err)
{
desc->buffer = buffer;
desc->size = size;
if (size)
- decode_tree_entry(desc, buffer, size);
+ return decode_tree_entry(desc, buffer, size, err);
+ return 0;
+}
+
+void init_tree_desc(struct tree_desc *desc, const void *buffer, unsigned long size)
+{
+ struct strbuf err = STRBUF_INIT;
+ if (init_tree_desc_internal(desc, buffer, size, &err))
+ die("%s", err.buf);
+ strbuf_release(&err);
+}
+
+int init_tree_desc_gently(struct tree_desc *desc, const void *buffer, unsigned long size)
+{
+ struct strbuf err = STRBUF_INIT;
+ int result = init_tree_desc_internal(desc, buffer, size, &err);
+ if (result)
+ error("%s", err.buf);
+ strbuf_release(&err);
+ return result;
}
void *fill_tree_descriptor(struct tree_desc *desc, const unsigned char *sha1)
@@ -75,7 +102,7 @@ static void entry_extract(struct tree_desc *t, struct name_entry *a)
*a = t->entry;
}
-void update_tree_entry(struct tree_desc *desc)
+static int update_tree_entry_internal(struct tree_desc *desc, struct strbuf *err)
{
const void *buf = desc->buffer;
const unsigned char *end = desc->entry.oid->hash + 20;
@@ -89,7 +116,30 @@ void update_tree_entry(struct tree_desc *desc)
desc->buffer = buf;
desc->size = size;
if (size)
- decode_tree_entry(desc, buf, size);
+ return decode_tree_entry(desc, buf, size, err);
+ return 0;
+}
+
+void update_tree_entry(struct tree_desc *desc)
+{
+ struct strbuf err = STRBUF_INIT;
+ if (update_tree_entry_internal(desc, &err))
+ die("%s", err.buf);
+ strbuf_release(&err);
+}
+
+int update_tree_entry_gently(struct tree_desc *desc)
+{
+ struct strbuf err = STRBUF_INIT;
+ if (update_tree_entry_internal(desc, &err)) {
+ error("%s", err.buf);
+ strbuf_release(&err);
+ /* Stop processing this tree after error */
+ desc->size = 0;
+ return -1;
+ }
+ strbuf_release(&err);
+ return 0;
}
int tree_entry(struct tree_desc *desc, struct name_entry *entry)
@@ -102,6 +152,17 @@ int tree_entry(struct tree_desc *desc, struct name_entry *entry)
return 1;
}
+int tree_entry_gently(struct tree_desc *desc, struct name_entry *entry)
+{
+ if (!desc->size)
+ return 0;
+
+ *entry = desc->entry;
+ if (update_tree_entry_gently(desc))
+ return 0;
+ return 1;
+}
+
void setup_traverse_info(struct traverse_info *info, const char *base)
{
int pathlen = strlen(base);
diff --git a/tree-walk.h b/tree-walk.h
index 97a7d69..68bb78b 100644
--- a/tree-walk.h
+++ b/tree-walk.h
@@ -25,14 +25,22 @@ static inline int tree_entry_len(const struct name_entry *ne)
return (const char *)ne->oid - ne->path - 1;
}
+/*
+ * The _gently versions of these functions warn and return false on a
+ * corrupt tree entry rather than dying,
+ */
+
void update_tree_entry(struct tree_desc *);
+int update_tree_entry_gently(struct tree_desc *);
void init_tree_desc(struct tree_desc *desc, const void *buf, unsigned long size);
+int init_tree_desc_gently(struct tree_desc *desc, const void *buf, unsigned long size);
/*
* Helper function that does both tree_entry_extract() and update_tree_entry()
* and returns true for success
*/
int tree_entry(struct tree_desc *, struct name_entry *);
+int tree_entry_gently(struct tree_desc *, struct name_entry *);
void *fill_tree_descriptor(struct tree_desc *desc, const unsigned char *sha1);
--
2.8.0.rc4.22.g8ae061a
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