[Libguestfs] [PATCH hivex 18/19] lib: node_add_child: Factor out subkey insertion into separate function.
Richard W.M. Jones
rjones at redhat.com
Thu Jul 25 10:39:00 UTC 2013
From: "Richard W.M. Jones" <rjones at redhat.com>
No functional change.
---
lib/write.c | 160 +++++++++++++++++++++++++++++++++---------------------------
1 file changed, 87 insertions(+), 73 deletions(-)
diff --git a/lib/write.c b/lib/write.c
index 236ff3c..371b1ab 100644
--- a/lib/write.c
+++ b/lib/write.c
@@ -407,6 +407,82 @@ compare_name_with_nk_name (hive_h *h, const char *name, hive_node_h nk_offs)
return r;
}
+static int
+insert_subkey (hive_h *h, const char *name,
+ size_t parent, size_t nkoffset, size_t *blocks)
+{
+ size_t old_offs = 0, new_offs = 0;
+ size_t i, j;
+ struct ntreg_lf_record *old_lf = NULL;
+
+ /* Find lf/lh key name just after the one we are inserting. */
+ for (i = 0; blocks[i] != 0; ++i) {
+ if (BLOCK_ID_EQ (h, blocks[i], "lf") || BLOCK_ID_EQ (h, blocks[i], "lh")) {
+ old_offs = blocks[i];
+ old_lf = (struct ntreg_lf_record *) ((char *) h->addr + old_offs);
+ for (j = 0; j < le16toh (old_lf->nr_keys); ++j) {
+ hive_node_h nk_offs = le32toh (old_lf->keys[j].offset);
+ nk_offs += 0x1000;
+ if (compare_name_with_nk_name (h, name, nk_offs) < 0)
+ goto insert_it;
+ }
+ }
+ }
+
+ /* Insert it at the end.
+ * old_offs points to the last lf record, set j.
+ */
+ assert (old_offs != 0); /* should never happen if nr_subkeys > 0 */
+ j = le16toh (old_lf->nr_keys);
+
+ /* Insert it. */
+ insert_it:
+ DEBUG (2, "insert key in existing lh-record at 0x%zx, posn %zu",
+ old_offs, j);
+
+ new_offs = insert_lf_record (h, old_offs, j, name, nkoffset);
+ if (new_offs == 0)
+ return -1;
+
+ DEBUG (2, "new lh-record at 0x%zx", new_offs);
+
+ /* Recalculate pointers that could have been invalidated by
+ * previous call to allocate_block (via new_lh_record).
+ */
+ struct ntreg_nk_record *parent_nk =
+ (struct ntreg_nk_record *) ((char *) h->addr + parent);
+
+ /* If the lf/lh-record was directly referenced by the parent nk,
+ * then update the parent nk.
+ */
+ if (le32toh (parent_nk->subkey_lf) + 0x1000 == old_offs)
+ parent_nk->subkey_lf = htole32 (new_offs - 0x1000);
+ /* Else we have to look for the intermediate ri-record and update
+ * that in-place.
+ */
+ else {
+ for (i = 0; blocks[i] != 0; ++i) {
+ if (BLOCK_ID_EQ (h, blocks[i], "ri")) {
+ struct ntreg_ri_record *ri =
+ (struct ntreg_ri_record *) ((char *) h->addr + blocks[i]);
+ for (j = 0; j < le16toh (ri->nr_offsets); ++j)
+ if (le32toh (ri->offset[j] + 0x1000) == old_offs) {
+ ri->offset[j] = htole32 (new_offs - 0x1000);
+ goto found_it;
+ }
+ }
+ }
+
+ /* Not found .. This is an internal error. */
+ SET_ERRNO (ENOTSUP, "could not find ri->lf link");
+ return -1;
+
+ found_it:;
+ }
+
+ return 0;
+}
+
hive_node_h
hivex_node_add_child (hive_h *h, hive_node_h parent, const char *name)
{
@@ -430,14 +506,14 @@ hivex_node_add_child (hive_h *h, hive_node_h parent, const char *name)
/* Create the new nk-record. */
static const char nk_id[2] = { 'n', 'k' };
size_t seg_len = sizeof (struct ntreg_nk_record) + strlen (name);
- hive_node_h node = allocate_block (h, seg_len, nk_id);
- if (node == 0)
+ hive_node_h nkoffset = allocate_block (h, seg_len, nk_id);
+ if (nkoffset == 0)
return 0;
- DEBUG (2, "allocated new nk-record for child at 0x%zx", node);
+ DEBUG (2, "allocated new nk-record for child at 0x%zx", nkoffset);
struct ntreg_nk_record *nk =
- (struct ntreg_nk_record *) ((char *) h->addr + node);
+ (struct ntreg_nk_record *) ((char *) h->addr + nkoffset);
nk->flags = htole16 (0x0020); /* key is ASCII. */
nk->parent = htole32 (parent - 0x1000);
nk->subkey_lf = htole32 (0xffffffff);
@@ -488,13 +564,13 @@ hivex_node_add_child (hive_h *h, hive_node_h parent, const char *name)
return 0;
free (unused);
- size_t i, j;
+ size_t i;
size_t nr_subkeys_in_parent_nk = le32toh (parent_nk->nr_subkeys);
if (nr_subkeys_in_parent_nk == 0) { /* No subkeys case. */
/* Free up any existing intermediate blocks. */
for (i = 0; blocks[i] != 0; ++i)
mark_block_unused (h, blocks[i]);
- size_t lh_offs = new_lh_record (h, name, node);
+ size_t lh_offs = new_lh_record (h, name, nkoffset);
if (lh_offs == 0) {
free (blocks);
return 0;
@@ -503,7 +579,7 @@ hivex_node_add_child (hive_h *h, hive_node_h parent, const char *name)
/* Recalculate pointers that could have been invalidated by
* previous call to allocate_block (via new_lh_record).
*/
- nk = (struct ntreg_nk_record *) ((char *) h->addr + node);
+ nk = (struct ntreg_nk_record *) ((char *) h->addr + nkoffset);
parent_nk = (struct ntreg_nk_record *) ((char *) h->addr + parent);
DEBUG (2, "no keys, allocated new lh-record at 0x%zx", lh_offs);
@@ -511,78 +587,16 @@ hivex_node_add_child (hive_h *h, hive_node_h parent, const char *name)
parent_nk->subkey_lf = htole32 (lh_offs - 0x1000);
}
else { /* Insert subkeys case. */
- size_t old_offs = 0, new_offs = 0;
- struct ntreg_lf_record *old_lf = NULL;
-
- /* Find lf/lh key name just after the one we are inserting. */
- for (i = 0; blocks[i] != 0; ++i) {
- if (BLOCK_ID_EQ (h, blocks[i], "lf") ||
- BLOCK_ID_EQ (h, blocks[i], "lh")) {
- old_offs = blocks[i];
- old_lf = (struct ntreg_lf_record *) ((char *) h->addr + old_offs);
- for (j = 0; j < le16toh (old_lf->nr_keys); ++j) {
- hive_node_h nk_offs = le32toh (old_lf->keys[j].offset);
- nk_offs += 0x1000;
- if (compare_name_with_nk_name (h, name, nk_offs) < 0)
- goto insert_it;
- }
- }
- }
-
- /* Insert it at the end.
- * old_offs points to the last lf record, set j.
- */
- assert (old_offs != 0); /* should never happen if nr_subkeys > 0 */
- j = le16toh (old_lf->nr_keys);
-
- /* Insert it. */
- insert_it:
- DEBUG (2, "insert key in existing lh-record at 0x%zx, posn %zu",
- old_offs, j);
-
- new_offs = insert_lf_record (h, old_offs, j, name, node);
- if (new_offs == 0) {
+ if (insert_subkey (h, name, parent, nkoffset, blocks) == -1) {
free (blocks);
return 0;
}
/* Recalculate pointers that could have been invalidated by
- * previous call to allocate_block (via insert_lf_record).
+ * previous call to allocate_block (via new_lh_record).
*/
- nk = (struct ntreg_nk_record *) ((char *) h->addr + node);
+ nk = (struct ntreg_nk_record *) ((char *) h->addr + nkoffset);
parent_nk = (struct ntreg_nk_record *) ((char *) h->addr + parent);
-
- DEBUG (2, "new lh-record at 0x%zx", new_offs);
-
- /* If the lf/lh-record was directly referenced by the parent nk,
- * then update the parent nk.
- */
- if (le32toh (parent_nk->subkey_lf) + 0x1000 == old_offs)
- parent_nk->subkey_lf = htole32 (new_offs - 0x1000);
- /* Else we have to look for the intermediate ri-record and update
- * that in-place.
- */
- else {
- for (i = 0; blocks[i] != 0; ++i) {
- if (BLOCK_ID_EQ (h, blocks[i], "ri")) {
- struct ntreg_ri_record *ri =
- (struct ntreg_ri_record *) ((char *) h->addr + blocks[i]);
- for (j = 0; j < le16toh (ri->nr_offsets); ++j)
- if (le32toh (ri->offset[j] + 0x1000) == old_offs) {
- ri->offset[j] = htole32 (new_offs - 0x1000);
- goto found_it;
- }
- }
- }
-
- /* Not found .. This is an internal error. */
- SET_ERRNO (ENOTSUP, "could not find ri->lf link");
- free (blocks);
- return 0;
-
- found_it:
- ;
- }
}
free (blocks);
@@ -596,7 +610,7 @@ hivex_node_add_child (hive_h *h, hive_node_h parent, const char *name)
if (max < strlen (name) * 2) /* *2 because "recoded" in UTF16-LE. */
parent_nk->max_subkey_name_len = htole16 (strlen (name) * 2);
- return node;
+ return nkoffset;
}
/* Decrement the refcount of an sk-record, and if it reaches zero,
--
1.8.3.1
More information about the Libguestfs
mailing list