(len+thistime)*2);
if(buffer == NULL) {
DEBUG(0, ("regdb_store_keys: Failed to realloc "
- "memory of size [%d]\n",
- (len+thistime)*2));
+ "memory of size [%u]\n",
+ (unsigned int)(len+thistime)*2));
ret = false;
goto done;
}
goto done;
}
+ /*
+ * Delete a sorted subkey cache for regdb_key_exists, will be
+ * recreated automatically
+ */
+ keyname = talloc_asprintf(ctx, "%s/%s", REG_SORTED_SUBKEYS_PREFIX,
+ keyname);
+ if (keyname != NULL) {
+ dbwrap_delete_bystring(regdb, keyname);
+ }
+
done:
TALLOC_FREE(ctx);
SAFE_FREE(buffer);
return ret;
}
+/*
+ * regdb_key_exists() is a very frequent operation. It can be quite
+ * time-consuming to fully fetch the parent's subkey list, talloc_strdup all
+ * subkeys and then compare the keyname linearly to all the parent's subkeys.
+ *
+ * The following code tries to make this operation as efficient as possible:
+ * Per registry key we create a list of subkeys that is very efficient to
+ * search for existence of a subkey. Its format is:
+ *
+ * 4 bytes num_subkeys
+ * 4*num_subkey bytes offset into the string array
+ * then follows a sorted list of subkeys in uppercase
+ *
+ * This record is created by create_sorted_subkeys() on demand if it does not
+ * exist. scan_parent_subkeys() uses regdb->parse_record to search the sorted
+ * list, the parsing code and the binary search can be found in
+ * parent_subkey_scanner. The code uses parse_record() to avoid a memcpy of
+ * the potentially large subkey record.
+ *
+ * The sorted subkey record is deleted in regdb_store_keys_internal and
+ * recreated on demand.
+ */
+
+static int cmp_keynames(const void *p1, const void *p2)
+{
+ return StrCaseCmp(*((char **)p1), *((char **)p2));
+}
+
+static bool create_sorted_subkeys(const char *key, const char *sorted_keyname)
+{
+ char **sorted_subkeys;
+ REGSUBKEY_CTR *ctr;
+ bool result = false;
+ NTSTATUS status;
+ char *buf;
+ char *p;
+ int i, res;
+ size_t len;
+
+ if (regdb->transaction_start(regdb) != 0) {
+ DEBUG(0, ("create_sorted_subkeys: transaction_start "
+ "failed\n"));
+ return false;
+ }
+
+ ctr = talloc(talloc_tos(), REGSUBKEY_CTR);
+ if (ctr == NULL) {
+ goto fail;
+ }
+
+ res = regdb_fetch_keys(key, ctr);
+ if (res == -1) {
+ goto fail;
+ }
+
+ sorted_subkeys = talloc_array(ctr, char *, ctr->num_subkeys);
+ if (sorted_subkeys == NULL) {
+ goto fail;
+ }
+
+ len = 4 + 4*ctr->num_subkeys;
+
+ for (i = 0; i<ctr->num_subkeys; i++) {
+ sorted_subkeys[i] = talloc_strdup_upper(sorted_subkeys,
+ ctr->subkeys[i]);
+ if (sorted_subkeys[i] == NULL) {
+ goto fail;
+ }
+ len += strlen(sorted_subkeys[i])+1;
+ }
+
+ qsort(sorted_subkeys, ctr->num_subkeys, sizeof(char *), cmp_keynames);
+
+ buf = talloc_array(ctr, char, len);
+ if (buf == NULL) {
+ goto fail;
+ }
+ p = buf + 4 + 4*ctr->num_subkeys;
+
+ SIVAL(buf, 0, ctr->num_subkeys);
+
+ for (i=0; i<ctr->num_subkeys; i++) {
+ ptrdiff_t offset = p - buf;
+ SIVAL(buf, 4 + 4*i, offset);
+ strlcpy(p, sorted_subkeys[i], len-offset);
+ p += strlen(sorted_subkeys[i]) + 1;
+ }
+
+ status = dbwrap_store_bystring(
+ regdb, sorted_keyname, make_tdb_data((uint8_t *)buf, len),
+ TDB_REPLACE);
+ if (!NT_STATUS_IS_OK(status)) {
+ /*
+ * Don't use a "goto fail;" here, this would commit the broken
+ * transaction. See below for an explanation.
+ */
+ if (regdb->transaction_cancel(regdb) == -1) {
+ DEBUG(0, ("create_sorted_subkeys: transaction_cancel "
+ "failed\n"));
+ }
+ TALLOC_FREE(ctr);
+ return false;
+ }
+
+ result = true;
+ fail:
+ /*
+ * We only get here via the "goto fail" when we did not write anything
+ * yet. Using transaction_commit even in a failure case is necessary
+ * because this (disposable) call might be nested in other
+ * transactions. Doing a cancel here would destroy the possibility of
+ * a transaction_commit for transactions that we might be wrapped in.
+ */
+ if (regdb->transaction_commit(regdb) == -1) {
+ DEBUG(0, ("create_sorted_subkeys: transaction_start "
+ "failed\n"));
+ goto fail;
+ }
+
+ TALLOC_FREE(ctr);
+ return result;
+}
+
+struct scan_subkey_state {
+ char *name;
+ bool scanned;
+ bool found;
+};
+
+static int parent_subkey_scanner(TDB_DATA key, TDB_DATA data,
+ void *private_data)
+{
+ struct scan_subkey_state *state =
+ (struct scan_subkey_state *)private_data;
+ uint32_t num_subkeys;
+ uint32_t l, u;
+
+ if (data.dsize < sizeof(uint32_t)) {
+ return -1;
+ }
+
+ state->scanned = true;
+ state->found = false;
+
+ tdb_unpack(data.dptr, data.dsize, "d", &num_subkeys);
+
+ l = 0;
+ u = num_subkeys;
+
+ while (l < u) {
+ uint32_t idx = (l+u)/2;
+ char *s = (char *)data.dptr + IVAL(data.dptr, 4 + 4*idx);
+ int comparison = strcmp(state->name, s);
+
+ if (comparison < 0) {
+ u = idx;
+ } else if (comparison > 0) {
+ l = idx + 1;
+ } else {
+ state->found = true;
+ return 0;
+ }
+ }
+ return 0;
+}
+
+static bool scan_parent_subkeys(const char *parent, const char *name)
+{
+ char *path = NULL;
+ char *key = NULL;
+ struct scan_subkey_state state = { 0, };
+ bool result = false;
+ int res;
+
+ state.name = NULL;
+
+ path = normalize_reg_path(talloc_tos(), parent);
+ if (path == NULL) {
+ goto fail;
+ }
+
+ key = talloc_asprintf(talloc_tos(), "%s/%s",
+ REG_SORTED_SUBKEYS_PREFIX, path);
+ if (key == NULL) {
+ goto fail;
+ }
+
+ state.name = talloc_strdup_upper(talloc_tos(), name);
+ if (state.name == NULL) {
+ goto fail;
+ }
+ state.scanned = false;
+
+ res = regdb->parse_record(regdb, string_term_tdb_data(key),
+ parent_subkey_scanner, &state);
+
+ if (state.scanned) {
+ result = state.found;
+ } else {
+ if (!create_sorted_subkeys(path, key)) {
+ goto fail;
+ }
+ res = regdb->parse_record(regdb, string_term_tdb_data(key),
+ parent_subkey_scanner, &state);
+ if ((res == 0) && (state.scanned)) {
+ result = state.found;
+ }
+ }
+
+ fail:
+ TALLOC_FREE(path);
+ TALLOC_FREE(state.name);
+ return result;
+}
/**
* Check for the existence of a key.
value = regdb_fetch_key_internal(mem_ctx, path);
ret = (value.dptr != NULL);
} else {
- /* get the list of subkeys of the parent key */
- uint32 num_items, len, i;
- fstring subkeyname;
-
*p = '\0';
- p++;
- value = regdb_fetch_key_internal(mem_ctx, path);
- if (value.dptr == NULL) {
- goto done;
- }
-
- len = tdb_unpack(value.dptr, value.dsize, "d", &num_items);
- for (i = 0; i < num_items; i++) {
- len += tdb_unpack(value.dptr +len, value.dsize -len,
- "f", &subkeyname);
- if (strequal(subkeyname, p)) {
- ret = true;
- goto done;
- }
- }
+ ret = scan_parent_subkeys(path, p+1);
}
done:
git.samba.org / ira / wip.git / blobdiff