+static WERROR regdb_create_subkey(const char *key, const char *subkey)
+{
+ WERROR werr;
+ struct regsubkey_ctr *subkeys;
+ TALLOC_CTX *mem_ctx = talloc_stackframe();
+
+ if (!regdb_key_is_base_key(key) && !regdb_key_exists(key)) {
+ werr = WERR_NOT_FOUND;
+ goto done;
+ }
+
+ werr = regsubkey_ctr_init(mem_ctx, &subkeys);
+ W_ERROR_NOT_OK_GOTO_DONE(werr);
+
+ if (regdb_fetch_keys(key, subkeys) < 0) {
+ werr = WERR_REG_IO_FAILURE;
+ goto done;
+ }
+
+ if (regsubkey_ctr_key_exists(subkeys, subkey)) {
+ werr = WERR_OK;
+ goto done;
+ }
+
+ talloc_free(subkeys);
+
+ werr = regdb_transaction_start();
+ W_ERROR_NOT_OK_GOTO_DONE(werr);
+
+ werr = regsubkey_ctr_init(mem_ctx, &subkeys);
+ W_ERROR_NOT_OK_GOTO(werr, cancel);
+
+ if (regdb_fetch_keys(key, subkeys) < 0) {
+ werr = WERR_REG_IO_FAILURE;
+ goto cancel;
+ }
+
+ werr = regsubkey_ctr_addkey(subkeys, subkey);
+ W_ERROR_NOT_OK_GOTO(werr, cancel);
+
+ if (!regdb_store_keys_internal(key, subkeys)) {
+ DEBUG(0, (__location__ " failed to store new subkey list for "
+ "parent key %s\n", key));
+ werr = WERR_REG_IO_FAILURE;
+ goto cancel;
+ }
+
+ werr = regdb_transaction_commit();
+ if (!W_ERROR_IS_OK(werr)) {
+ DEBUG(0, (__location__ " failed to commit transaction: %s\n",
+ win_errstr(werr)));
+ }
+
+ goto done;
+
+cancel:
+ werr = regdb_transaction_cancel();
+ if (!W_ERROR_IS_OK(werr)) {
+ DEBUG(0, (__location__ " failed to cancel transaction: %s\n",
+ win_errstr(werr)));
+ }
+
+done:
+ talloc_free(mem_ctx);
+ return werr;
+}
+
+static WERROR regdb_delete_subkey(const char *key, const char *subkey)
+{
+ WERROR werr, werr2;
+ struct regsubkey_ctr *subkeys;
+ char *path;
+ TALLOC_CTX *mem_ctx = talloc_stackframe();
+
+ if (!regdb_key_is_base_key(key) && !regdb_key_exists(key)) {
+ werr = WERR_NOT_FOUND;
+ goto done;
+ }
+
+ path = talloc_asprintf(mem_ctx, "%s/%s", key, subkey);
+ if (path == NULL) {
+ werr = WERR_NOMEM;
+ goto done;
+ }
+
+ if (!regdb_key_exists(path)) {
+ werr = WERR_OK;
+ goto done;
+ }
+
+ werr = regdb_transaction_start();
+ W_ERROR_NOT_OK_GOTO_DONE(werr);
+
+ werr = regdb_delete_key_lists(path);
+ W_ERROR_NOT_OK_GOTO(werr, cancel);
+
+ werr = regsubkey_ctr_init(mem_ctx, &subkeys);
+ W_ERROR_NOT_OK_GOTO(werr, cancel);
+
+ if (regdb_fetch_keys(key, subkeys) < 0) {
+ werr = WERR_REG_IO_FAILURE;
+ goto cancel;
+ }
+
+ werr = regsubkey_ctr_delkey(subkeys, subkey);
+ W_ERROR_NOT_OK_GOTO(werr, cancel);
+
+ if (!regdb_store_keys_internal(key, subkeys)) {
+ DEBUG(0, (__location__ " failed to store new subkey_list for "
+ "parent key %s\n", key));
+ werr = WERR_REG_IO_FAILURE;
+ goto cancel;
+ }
+
+ werr = regdb_transaction_commit();
+ if (!W_ERROR_IS_OK(werr)) {
+ DEBUG(0, (__location__ " failed to commit transaction: %s\n",
+ win_errstr(werr)));
+ }
+
+ goto done;
+
+cancel:
+ werr2 = regdb_transaction_cancel();
+ if (!W_ERROR_IS_OK(werr2)) {
+ DEBUG(0, (__location__ " failed to cancel transaction: %s\n",
+ win_errstr(werr2)));
+ }
+
+done:
+ talloc_free(mem_ctx);
+ return werr;
+}
+
+static TDB_DATA regdb_fetch_key_internal(TALLOC_CTX *mem_ctx, const char *key)
+{
+ char *path = NULL;
+ TDB_DATA data;
+
+ path = normalize_reg_path(mem_ctx, key);
+ if (!path) {
+ return make_tdb_data(NULL, 0);
+ }
+
+ data = dbwrap_fetch_bystring(regdb, mem_ctx, path);
+
+ TALLOC_FREE(path);
+ return data;
+}
+
+
+/**
+ * check whether a given key name represents a base key,
+ * i.e one without a subkey separator ('/' or '\').
+ */
+static bool regdb_key_is_base_key(const char *key)
+{
+ TALLOC_CTX *mem_ctx = talloc_stackframe();
+ bool ret = false;
+ char *path;
+
+ if (key == NULL) {
+ goto done;
+ }
+
+ path = normalize_reg_path(mem_ctx, key);
+ if (path == NULL) {
+ DEBUG(0, ("out of memory! (talloc failed)\n"));
+ goto done;
+ }
+
+ if (*path == '\0') {
+ goto done;
+ }
+
+ ret = (strrchr(path, '/') == NULL);
+
+done:
+ TALLOC_FREE(mem_ctx);
+ 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;
+ struct regsubkey_ctr *ctr;
+ bool result = false;
+ NTSTATUS status;
+ char *buf;
+ char *p;
+ int i, res;
+ size_t len;
+ int num_subkeys;
+ WERROR werr;
+
+ if (regdb->transaction_start(regdb) != 0) {
+ DEBUG(0, ("create_sorted_subkeys: transaction_start "
+ "failed\n"));
+ return false;
+ }
+
+ werr = regsubkey_ctr_init(talloc_tos(), &ctr);
+ if (!W_ERROR_IS_OK(werr)) {
+ goto fail;
+ }
+
+ res = regdb_fetch_keys(key, ctr);
+ if (res == -1) {
+ goto fail;
+ }
+
+ num_subkeys = regsubkey_ctr_numkeys(ctr);
+ sorted_subkeys = talloc_array(ctr, char *, num_subkeys);
+ if (sorted_subkeys == NULL) {
+ goto fail;
+ }
+
+ 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) {
+ goto fail;
+ }
+ len += strlen(sorted_subkeys[i])+1;
+ }
+
+ qsort(sorted_subkeys, num_subkeys, sizeof(char *), cmp_keynames);
+
+ buf = talloc_array(ctr, char, len);
+ if (buf == NULL) {
+ goto fail;
+ }
+ 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(
+ 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.
+ *
+ * Existence of a key is authoritatively defined by its
+ * existence in the list of subkeys of its parent key.
+ * The exeption of this are keys without a parent key,
+ * i.e. the "base" keys (HKLM, HKCU, ...).
+ */
+static bool regdb_key_exists(const char *key)
+{
+ TALLOC_CTX *mem_ctx = talloc_stackframe();
+ TDB_DATA value;
+ bool ret = false;
+ char *path, *p;
+
+ if (key == NULL) {
+ goto done;
+ }
+
+ path = normalize_reg_path(mem_ctx, key);
+ if (path == NULL) {
+ DEBUG(0, ("out of memory! (talloc failed)\n"));
+ goto done;
+ }
+
+ if (*path == '\0') {
+ goto done;
+ }
+
+ p = strrchr(path, '/');
+ if (p == NULL) {
+ /* this is a base key */
+ value = regdb_fetch_key_internal(mem_ctx, path);
+ ret = (value.dptr != NULL);
+ } else {
+ *p = '\0';
+ ret = scan_parent_subkeys(path, p+1);
+ }
+
+done:
+ TALLOC_FREE(mem_ctx);
+ return ret;
+}
+