static bool regdb_store_values_internal(struct db_context *db, const char *key,
struct regval_ctr *values);
-static NTSTATUS create_sorted_subkeys(const char *key);
static WERROR regdb_create_basekey(struct db_context *db, const char *key);
static WERROR regdb_create_subkey_internal(struct db_context *db,
const char *key,
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_internal2 and
- * recreated on demand.
- */
-
-static int cmp_keynames(char **p1, char **p2)
-{
- return strcasecmp_m(*p1, *p2);
-}
-
-struct create_sorted_subkeys_context {
- const char *key;
- const char *sorted_keyname;
-};
-
-static NTSTATUS create_sorted_subkeys_action(struct db_context *db,
- void *private_data)
-{
- char **sorted_subkeys;
- struct regsubkey_ctr *ctr;
- NTSTATUS status;
- char *buf;
- char *p;
- int i;
- size_t len;
- int num_subkeys;
- struct create_sorted_subkeys_context *sorted_ctx;
-
- sorted_ctx = (struct create_sorted_subkeys_context *)private_data;
-
- /*
- * In this function, we only treat failing of the actual write to
- * the db as a real error. All preliminary errors, at a stage when
- * nothing has been written to the DB yet are treated as success
- * to be committed (as an empty transaction).
- *
- * The reason is that 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.
- */
-
- status = werror_to_ntstatus(regsubkey_ctr_init(talloc_tos(), &ctr));
- if (!NT_STATUS_IS_OK(status)) {
- /* don't treat this as an error */
- status = NT_STATUS_OK;
- goto done;
- }
-
- status = werror_to_ntstatus(regdb_fetch_keys_internal(db,
- sorted_ctx->key,
- ctr));
- if (!NT_STATUS_IS_OK(status)) {
- /* don't treat this as an error */
- status = NT_STATUS_OK;
- goto done;
- }
-
- num_subkeys = regsubkey_ctr_numkeys(ctr);
- sorted_subkeys = talloc_array(ctr, char *, num_subkeys);
- if (sorted_subkeys == NULL) {
- /* don't treat this as an error */
- goto done;
- }
-
- len = 4 + 4*num_subkeys;
-
- for (i = 0; i < num_subkeys; i++) {
- sorted_subkeys[i] = talloc_strdup_upper(sorted_subkeys,
- regsubkey_ctr_specific_key(ctr, i));
- if (sorted_subkeys[i] == NULL) {
- /* don't treat this as an error */
- goto done;
- }
- len += strlen(sorted_subkeys[i])+1;
- }
-
- TYPESAFE_QSORT(sorted_subkeys, num_subkeys, cmp_keynames);
-
- buf = talloc_array(ctr, char, len);
- if (buf == NULL) {
- /* don't treat this as an error */
- goto done;
- }
- p = buf + 4 + 4*num_subkeys;
-
- SIVAL(buf, 0, num_subkeys);
-
- for (i=0; i < 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(
- db, sorted_ctx->sorted_keyname, make_tdb_data((uint8_t *)buf,
- len),
- TDB_REPLACE);
-
-done:
- talloc_free(ctr);
- return status;
-}
-
-static NTSTATUS create_sorted_subkeys_internal(const char *key,
- const char *sorted_keyname)
-{
- NTSTATUS status;
- struct create_sorted_subkeys_context sorted_ctx;
-
- sorted_ctx.key = key;
- sorted_ctx.sorted_keyname = sorted_keyname;
-
- status = dbwrap_trans_do(regdb,
- create_sorted_subkeys_action,
- &sorted_ctx);
-
- return status;
-}
-
-static NTSTATUS create_sorted_subkeys(const char *key)
-{
- char *sorted_subkeys_keyname;
- NTSTATUS status;
-
- sorted_subkeys_keyname = talloc_asprintf(talloc_tos(), "%s\\%s",
- REG_SORTED_SUBKEYS_PREFIX,
- key);
- if (sorted_subkeys_keyname == NULL) {
- status = NT_STATUS_NO_MEMORY;
- goto done;
- }
-
- status = create_sorted_subkeys_internal(key, sorted_subkeys_keyname);
-
-done:
- return status;
-}
-
-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(struct db_context *db, 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 = db->parse_record(db, string_term_tdb_data(key),
- parent_subkey_scanner, &state);
-
- if (state.scanned) {
- result = state.found;
- } else {
- NTSTATUS status;
-
- res = db->transaction_start(db);
- if (res != 0) {
- DEBUG(0, ("error starting transaction\n"));
- goto fail;
- }
-
- DEBUG(2, (__location__ " WARNING: recreating the sorted "
- "subkeys cache for key '%s' from scan_parent_subkeys "
- "this should not happen (too frequently)...\n",
- path));
-
- status = create_sorted_subkeys_internal(path, key);
- if (!NT_STATUS_IS_OK(status)) {
- res = db->transaction_cancel(db);
- if (res != 0) {
- smb_panic("Failed to cancel transaction.");
- }
- goto fail;
- }
-
- res = db->parse_record(db, string_term_tdb_data(key),
- parent_subkey_scanner, &state);
- if ((res == 0) && (state.scanned)) {
- result = state.found;
- }
-
- res = db->transaction_commit(db);
- if (res != 0) {
- DEBUG(0, ("error committing transaction\n"));
- result = false;
- }
- }
-
- fail:
- TALLOC_FREE(path);
- TALLOC_FREE(state.name);
- return result;
-}
-
/**
* Check for the existence of a key.
*
git.samba.org / kai / samba.git / commitdiff