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authorLibravatar Junio C Hamano <gitster@pobox.com>2017-09-19 10:47:52 +0900
committerLibravatar Junio C Hamano <gitster@pobox.com>2017-09-19 10:47:52 +0900
commit30675f7021f92b0e830fdb3c96370826d8f6723f (patch)
tree9214d703463496ce599c3f24cb620e5eafea7361
parentMerge branch 'mg/timestamp-t-fix' (diff)
parentload_subtree(): check that `prefix_len` is in the expected range (diff)
downloadtgif-30675f7021f92b0e830fdb3c96370826d8f6723f.tar.xz
Merge branch 'mh/notes-cleanup'
Code clean-up. * mh/notes-cleanup: load_subtree(): check that `prefix_len` is in the expected range load_subtree(): declare some variables to be `size_t` hex_to_bytes(): simpler replacement for `get_oid_hex_segment()` get_oid_hex_segment(): don't pad the rest of `oid` load_subtree(): combine some common code get_oid_hex_segment(): return 0 on success load_subtree(): only consider blobs to be potential notes load_subtree(): check earlier whether an internal node is a tree entry load_subtree(): separate logic for internal vs. terminal entries load_subtree(): fix incorrect comment load_subtree(): reduce the scope of some local variables load_subtree(): remove unnecessary conditional notes: make GET_NIBBLE macro more robust
-rw-r--r--notes.c141
1 files changed, 70 insertions, 71 deletions
diff --git a/notes.c b/notes.c
index f090c88363..5c62862574 100644
--- a/notes.c
+++ b/notes.c
@@ -64,7 +64,7 @@ struct non_note {
#define CLR_PTR_TYPE(ptr) ((void *) ((uintptr_t) (ptr) & ~3))
#define SET_PTR_TYPE(ptr, type) ((void *) ((uintptr_t) (ptr) | (type)))
-#define GET_NIBBLE(n, sha1) (((sha1[(n) >> 1]) >> ((~(n) & 0x01) << 2)) & 0x0f)
+#define GET_NIBBLE(n, sha1) ((((sha1)[(n) >> 1]) >> ((~(n) & 0x01) << 2)) & 0x0f)
#define KEY_INDEX (GIT_SHA1_RAWSZ - 1)
#define FANOUT_PATH_SEPARATORS ((GIT_SHA1_HEXSZ / 2) - 1)
@@ -335,31 +335,20 @@ static void note_tree_free(struct int_node *tree)
}
/*
- * Convert a partial SHA1 hex string to the corresponding partial SHA1 value.
- * - hex - Partial SHA1 segment in ASCII hex format
- * - hex_len - Length of above segment. Must be multiple of 2 between 0 and 40
- * - sha1 - Partial SHA1 value is written here
- * - sha1_len - Max #bytes to store in sha1, Must be >= hex_len / 2, and < 20
- * Returns -1 on error (invalid arguments or invalid SHA1 (not in hex format)).
- * Otherwise, returns number of bytes written to sha1 (i.e. hex_len / 2).
- * Pads sha1 with NULs up to sha1_len (not included in returned length).
+ * Read `len` pairs of hexadecimal digits from `hex` and write the
+ * values to `binary` as `len` bytes. Return 0 on success, or -1 if
+ * the input does not consist of hex digits).
*/
-static int get_oid_hex_segment(const char *hex, unsigned int hex_len,
- unsigned char *oid, unsigned int oid_len)
+static int hex_to_bytes(unsigned char *binary, const char *hex, size_t len)
{
- unsigned int i, len = hex_len >> 1;
- if (hex_len % 2 != 0 || len > oid_len)
- return -1;
- for (i = 0; i < len; i++) {
+ for (; len; len--, hex += 2) {
unsigned int val = (hexval(hex[0]) << 4) | hexval(hex[1]);
+
if (val & ~0xff)
return -1;
- *oid++ = val;
- hex += 2;
+ *binary++ = val;
}
- for (; i < oid_len; i++)
- *oid++ = 0;
- return len;
+ return 0;
}
static int non_note_cmp(const struct non_note *a, const struct non_note *b)
@@ -417,13 +406,10 @@ static void load_subtree(struct notes_tree *t, struct leaf_node *subtree,
struct int_node *node, unsigned int n)
{
struct object_id object_oid;
- unsigned int prefix_len;
+ size_t prefix_len;
void *buf;
struct tree_desc desc;
struct name_entry entry;
- int len, path_len;
- unsigned char type;
- struct leaf_node *l;
buf = fill_tree_descriptor(&desc, &subtree->val_oid);
if (!buf)
@@ -431,66 +417,79 @@ static void load_subtree(struct notes_tree *t, struct leaf_node *subtree,
oid_to_hex(&subtree->val_oid));
prefix_len = subtree->key_oid.hash[KEY_INDEX];
- assert(prefix_len * 2 >= n);
+ if (prefix_len >= GIT_SHA1_RAWSZ)
+ BUG("prefix_len (%"PRIuMAX") is out of range", (uintmax_t)prefix_len);
+ if (prefix_len * 2 < n)
+ BUG("prefix_len (%"PRIuMAX") is too small", (uintmax_t)prefix_len);
memcpy(object_oid.hash, subtree->key_oid.hash, prefix_len);
while (tree_entry(&desc, &entry)) {
- path_len = strlen(entry.path);
- len = get_oid_hex_segment(entry.path, path_len,
- object_oid.hash + prefix_len, GIT_SHA1_RAWSZ - prefix_len);
- if (len < 0)
- goto handle_non_note; /* entry.path is not a SHA1 */
- len += prefix_len;
+ unsigned char type;
+ struct leaf_node *l;
+ size_t path_len = strlen(entry.path);
+
+ if (path_len == 2 * (GIT_SHA1_RAWSZ - prefix_len)) {
+ /* This is potentially the remainder of the SHA-1 */
+
+ if (!S_ISREG(entry.mode))
+ /* notes must be blobs */
+ goto handle_non_note;
+
+ if (hex_to_bytes(object_oid.hash + prefix_len, entry.path,
+ GIT_SHA1_RAWSZ - prefix_len))
+ goto handle_non_note; /* entry.path is not a SHA1 */
- /*
- * If object SHA1 is complete (len == 20), assume note object
- * If object SHA1 is incomplete (len < 20), and current
- * component consists of 2 hex chars, assume note subtree
- */
- if (len <= GIT_SHA1_RAWSZ) {
type = PTR_TYPE_NOTE;
- l = (struct leaf_node *)
- xcalloc(1, sizeof(struct leaf_node));
- oidcpy(&l->key_oid, &object_oid);
- oidcpy(&l->val_oid, entry.oid);
- if (len < GIT_SHA1_RAWSZ) {
- if (!S_ISDIR(entry.mode) || path_len != 2)
- goto handle_non_note; /* not subtree */
- l->key_oid.hash[KEY_INDEX] = (unsigned char) len;
- type = PTR_TYPE_SUBTREE;
- }
- if (note_tree_insert(t, node, n, l, type,
- combine_notes_concatenate))
- die("Failed to load %s %s into notes tree "
- "from %s",
- type == PTR_TYPE_NOTE ? "note" : "subtree",
- oid_to_hex(&l->key_oid), t->ref);
+ } else if (path_len == 2) {
+ /* This is potentially an internal node */
+ size_t len = prefix_len;
+
+ if (!S_ISDIR(entry.mode))
+ /* internal nodes must be trees */
+ goto handle_non_note;
+
+ if (hex_to_bytes(object_oid.hash + len++, entry.path, 1))
+ goto handle_non_note; /* entry.path is not a SHA1 */
+
+ /*
+ * Pad the rest of the SHA-1 with zeros,
+ * except for the last byte, where we write
+ * the length:
+ */
+ memset(object_oid.hash + len, 0, GIT_SHA1_RAWSZ - len - 1);
+ object_oid.hash[KEY_INDEX] = (unsigned char)len;
+
+ type = PTR_TYPE_SUBTREE;
+ } else {
+ /* This can't be part of a note */
+ goto handle_non_note;
}
+
+ l = xcalloc(1, sizeof(*l));
+ oidcpy(&l->key_oid, &object_oid);
+ oidcpy(&l->val_oid, entry.oid);
+ if (note_tree_insert(t, node, n, l, type,
+ combine_notes_concatenate))
+ die("Failed to load %s %s into notes tree "
+ "from %s",
+ type == PTR_TYPE_NOTE ? "note" : "subtree",
+ oid_to_hex(&l->key_oid), t->ref);
+
continue;
handle_non_note:
/*
- * Determine full path for this non-note entry:
- * The filename is already found in entry.path, but the
- * directory part of the path must be deduced from the subtree
- * containing this entry. We assume here that the overall notes
- * tree follows a strict byte-based progressive fanout
- * structure (i.e. using 2/38, 2/2/36, etc. fanouts, and not
- * e.g. 4/36 fanout). This means that if a non-note is found at
- * path "dead/beef", the following code will register it as
- * being found on "de/ad/beef".
- * On the other hand, if you use such non-obvious non-note
- * paths in the middle of a notes tree, you deserve what's
- * coming to you ;). Note that for non-notes that are not
- * SHA1-like at the top level, there will be no problems.
- *
- * To conclude, it is strongly advised to make sure non-notes
- * have at least one non-hex character in the top-level path
- * component.
+ * Determine full path for this non-note entry. The
+ * filename is already found in entry.path, but the
+ * directory part of the path must be deduced from the
+ * subtree containing this entry based on our
+ * knowledge that the overall notes tree follows a
+ * strict byte-based progressive fanout structure
+ * (i.e. using 2/38, 2/2/36, etc. fanouts).
*/
{
struct strbuf non_note_path = STRBUF_INIT;
const char *q = oid_to_hex(&subtree->key_oid);
- int i;
+ size_t i;
for (i = 0; i < prefix_len; i++) {
strbuf_addch(&non_note_path, *q++);
strbuf_addch(&non_note_path, *q++);