first cut at adding full transactions for ctdb to samba3
[jra/samba/.git] / source3 / registry / reg_backend_db.c
index 7513b3b2633d1ac2b5d84da0fb6b64b53fcc07c1..6f4c614b9a5a003154092cce685668c254b4d912 100644 (file)
@@ -28,6 +28,7 @@ static struct db_context *regdb = NULL;
 static int regdb_refcount;
 
 static bool regdb_key_exists(const char *key);
+static bool regdb_key_is_base_key(const char *key);
 
 /* List the deepest path into the registry.  All part components will be created.*/
 
@@ -389,14 +390,14 @@ WERROR regdb_init(void)
                return WERR_OK;
        }
 
-       regdb = db_open_trans(NULL, state_path("registry.tdb"), 0,
+       regdb = db_open(NULL, state_path("registry.tdb"), 0,
                              REG_TDB_FLAGS, O_RDWR, 0600);
        if (!regdb) {
-               regdb = db_open_trans(NULL, state_path("registry.tdb"), 0,
+               regdb = db_open(NULL, state_path("registry.tdb"), 0,
                                      REG_TDB_FLAGS, O_RDWR|O_CREAT, 0600);
                if (!regdb) {
                        werr = ntstatus_to_werror(map_nt_error_from_unix(errno));
-                       DEBUG(0,("regdb_init: Failed to open registry %s (%s)\n",
+                       DEBUG(1,("regdb_init: Failed to open registry %s (%s)\n",
                                state_path("registry.tdb"), strerror(errno) ));
                        return werr;
                }
@@ -415,7 +416,7 @@ WERROR regdb_init(void)
                           vers_id, REGVER_V1));
                status = dbwrap_trans_store_int32(regdb, vstring, REGVER_V1);
                if (!NT_STATUS_IS_OK(status)) {
-                       DEBUG(0, ("regdb_init: error storing %s = %d: %s\n",
+                       DEBUG(1, ("regdb_init: error storing %s = %d: %s\n",
                                  vstring, REGVER_V1, nt_errstr(status)));
                        return ntstatus_to_werror(status);
                } else {
@@ -443,7 +444,7 @@ WERROR regdb_open( void )
        
        become_root();
 
-       regdb = db_open_trans(NULL, state_path("registry.tdb"), 0,
+       regdb = db_open(NULL, state_path("registry.tdb"), 0,
                              REG_TDB_FLAGS, O_RDWR, 0600);
        if ( !regdb ) {
                result = ntstatus_to_werror( map_nt_error_from_unix( errno ) );
@@ -582,6 +583,10 @@ bool regdb_store_keys(const char *key, REGSUBKEY_CTR *ctr)
        TALLOC_CTX *ctx = talloc_stackframe();
        NTSTATUS status;
 
+       if (!regdb_key_is_base_key(key) && !regdb_key_exists(key)) {
+               goto fail;
+       }
+
        /*
         * fetch a list of the old subkeys so we can determine if anything has
         * changed
@@ -631,15 +636,28 @@ bool regdb_store_keys(const char *key, REGSUBKEY_CTR *ctr)
 
        regdb_fetch_keys(key, old_subkeys);
 
-       /* store the subkey list for the parent */
-
-       if (!regdb_store_keys_internal(key, ctr) ) {
-               DEBUG(0,("regdb_store_keys: Failed to store new subkey list "
-                        "for parent [%s]\n", key));
-               goto cancel;
-       }
+       /*
+        * Make the store operation as safe as possible without transactions:
+        *
+        * (1) For each subkey removed from ctr compared with old_subkeys:
+        *
+        *     (a) First delete the value db entry.
+        *
+        *     (b) Next delete the secdesc db record.
+        *
+        *     (c) Then delete the subkey list entry.
+        *
+        * (2) Now write the list of subkeys of the parent key,
+        *     deleting removed entries and adding new ones.
+        *
+        * (3) Finally create the subkey list entries for the added keys.
+        *
+        * This way if we crash half-way in between deleting the subkeys
+        * and storing the parent's list of subkeys, no old data can pop up
+        * out of the blue when re-adding keys later on.
+        */
 
-       /* now delete removed keys */
+       /* (1) delete removed keys' lists (values/secdesc/subkeys) */
 
        num_subkeys = regsubkey_ctr_numkeys(old_subkeys);
        for (i=0; i<num_subkeys; i++) {
@@ -653,7 +671,12 @@ bool regdb_store_keys(const char *key, REGSUBKEY_CTR *ctr)
                        continue;
                }
 
-               path = talloc_asprintf(ctx, "%s/%s", key, oldkeyname);
+               /* (a) Delete the value list for this key */
+
+               path = talloc_asprintf(ctx, "%s/%s/%s",
+                               REG_VALUE_PREFIX,
+                               key,
+                               oldkeyname );
                if (!path) {
                        goto cancel;
                }
@@ -661,15 +684,14 @@ bool regdb_store_keys(const char *key, REGSUBKEY_CTR *ctr)
                if (!path) {
                        goto cancel;
                }
-               status = dbwrap_delete_bystring(regdb, path);
-               if (!NT_STATUS_IS_OK(status)) {
-                       DEBUG(1, ("Deleting %s failed\n", path));
-                       goto cancel;
-               }
-
+               /* Ignore errors here, we might have no values around */
+               dbwrap_delete_bystring(regdb, path);
                TALLOC_FREE(path);
+
+               /* (b) Delete the secdesc for this key */
+
                path = talloc_asprintf(ctx, "%s/%s/%s",
-                               REG_VALUE_PREFIX,
+                               REG_SECDESC_PREFIX,
                                key,
                                oldkeyname );
                if (!path) {
@@ -679,17 +701,50 @@ bool regdb_store_keys(const char *key, REGSUBKEY_CTR *ctr)
                if (!path) {
                        goto cancel;
                }
+               status = dbwrap_delete_bystring(regdb, path);
+               /* Don't fail if there are no values around. */
+               if (!NT_STATUS_IS_OK(status) &&
+                   !NT_STATUS_EQUAL(status, NT_STATUS_NOT_FOUND))
+               {
+                       DEBUG(1, ("Deleting %s failed: %s\n", path,
+                                 nt_errstr(status)));
+                       goto cancel;
+               }
+               TALLOC_FREE(path);
 
-               /*
-                * Ignore errors here, we might have no values around
-                */
-               dbwrap_delete_bystring(regdb, path);
+               /* (c) Delete the list of subkeys of this key */
+
+               path = talloc_asprintf(ctx, "%s/%s", key, oldkeyname);
+               if (!path) {
+                       goto cancel;
+               }
+               path = normalize_reg_path(ctx, path);
+               if (!path) {
+                       goto cancel;
+               }
+               status = dbwrap_delete_bystring(regdb, path);
+               /* Don't fail if the subkey record was not found. */
+               if (!NT_STATUS_IS_OK(status) &&
+                   !NT_STATUS_EQUAL(status, NT_STATUS_NOT_FOUND))
+               {
+                       DEBUG(1, ("Deleting %s failed: %s\n", path,
+                                 nt_errstr(status)));
+                       goto cancel;
+               }
                TALLOC_FREE(path);
        }
 
        TALLOC_FREE(old_subkeys);
 
-       /* now create records for any subkeys that don't already exist */
+       /* (2) store the subkey list for the parent */
+
+       if (!regdb_store_keys_internal(key, ctr) ) {
+               DEBUG(0,("regdb_store_keys: Failed to store new subkey list "
+                        "for parent [%s]\n", key));
+               goto cancel;
+       }
+
+       /* (3) now create records for any subkeys that don't already exist */
 
        num_subkeys = regsubkey_ctr_numkeys(ctr);
 
@@ -770,6 +825,38 @@ static TDB_DATA regdb_fetch_key_internal(TALLOC_CTX *mem_ctx, const char *key)
 }
 
 
+/**
+ * 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;
+}
+
+
 /**
  * Check for the existence of a key.
  *
@@ -853,21 +940,22 @@ int regdb_fetch_keys(const char *key, REGSUBKEY_CTR *ctr)
        DEBUG(11,("regdb_fetch_keys: Enter key => [%s]\n", key ? key : "NULL"));
 
        if (!regdb_key_exists(key)) {
-               goto fail;
+               goto done;
        }
 
        ctr->seqnum = regdb_get_seqnum();
 
        value = regdb_fetch_key_internal(frame, key);
 
-       buf = value.dptr;
-       buflen = value.dsize;
-
-       if ( !buf ) {
-               DEBUG(5,("regdb_fetch_keys: tdb lookup failed to locate key [%s]\n", key));
-               goto fail;
+       if (value.dptr == NULL) {
+               DEBUG(10, ("regdb_fetch_keys: no subkeys found for key [%s]\n",
+                          key));
+               ret = 0;
+               goto done;
        }
 
+       buf = value.dptr;
+       buflen = value.dsize;
        len = tdb_unpack( buf, buflen, "d", &num_items);
 
        for (i=0; i<num_items; i++) {
@@ -876,14 +964,14 @@ int regdb_fetch_keys(const char *key, REGSUBKEY_CTR *ctr)
                if (!W_ERROR_IS_OK(werr)) {
                        DEBUG(5, ("regdb_fetch_keys: regsubkey_ctr_addkey "
                                  "failed: %s\n", dos_errstr(werr)));
-                       goto fail;
+                       goto done;
                }
        }
 
        DEBUG(11,("regdb_fetch_keys: Exit [%d] items\n", num_items));
 
        ret = num_items;
- fail:
+done:
        TALLOC_FREE(frame);
        return ret;
 }
@@ -1018,6 +1106,10 @@ bool regdb_store_values( const char *key, REGVAL_CTR *values )
 
        DEBUG(10,("regdb_store_values: Looking for value of key [%s] \n", key));
 
+       if (!regdb_key_exists(key)) {
+               goto done;
+       }
+
        ZERO_STRUCT(data);
 
        len = regdb_pack_values(values, data.dptr, data.dsize);
@@ -1052,8 +1144,7 @@ bool regdb_store_values( const char *key, REGVAL_CTR *values )
                goto done;
        }
 
-       status = dbwrap_trans_store(regdb, string_term_tdb_data(keystr), data,
-                                   TDB_REPLACE);
+       status = dbwrap_trans_store_bystring(regdb, keystr, data, TDB_REPLACE);
 
        result = NT_STATUS_IS_OK(status);
 
@@ -1073,6 +1164,11 @@ static WERROR regdb_get_secdesc(TALLOC_CTX *mem_ctx, const char *key,
 
        DEBUG(10, ("regdb_get_secdesc: Getting secdesc of key [%s]\n", key));
 
+       if (!regdb_key_exists(key)) {
+               err = WERR_BADFILE;
+               goto done;
+       }
+
        tdbkey = talloc_asprintf(tmp_ctx, "%s/%s", REG_SECDESC_PREFIX, key);
        if (tdbkey == NULL) {
                err = WERR_NOMEM;
@@ -1109,6 +1205,11 @@ static WERROR regdb_set_secdesc(const char *key,
        WERROR err = WERR_NOMEM;
        TDB_DATA tdbdata;
 
+       if (!regdb_key_exists(key)) {
+               err = WERR_BADFILE;
+               goto done;
+       }
+
        tdbkey = talloc_asprintf(mem_ctx, "%s/%s", REG_SECDESC_PREFIX, key);
        if (tdbkey == NULL) {
                goto done;
@@ -1117,8 +1218,7 @@ static WERROR regdb_set_secdesc(const char *key,
 
        if (secdesc == NULL) {
                /* assuming a delete */
-               status = dbwrap_trans_delete(regdb,
-                                            string_term_tdb_data(tdbkey));
+               status = dbwrap_trans_delete_bystring(regdb, tdbkey);
                if (NT_STATUS_IS_OK(status)) {
                        err = WERR_OK;
                } else {
@@ -1134,8 +1234,7 @@ static WERROR regdb_set_secdesc(const char *key,
                goto done;
        }
 
-       status = dbwrap_trans_store(regdb, string_term_tdb_data(tdbkey),
-                                   tdbdata, 0);
+       status = dbwrap_trans_store_bystring(regdb, tdbkey, tdbdata, 0);
        if (!NT_STATUS_IS_OK(status)) {
                err = ntstatus_to_werror(status);
                goto done;