X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=ovsdb%2Fovsdb-server.c;h=a85a672a9ee958134fa86ac4be5fc18844c77b7c;hb=28c5588e8e1a8d091c5d2275232c35f2968a97fa;hp=919575a57b7f79e515c2f3c42439b7911c7453bf;hpb=fb6de52cd7054053f745a880f09607628fc3b7cd;p=sliver-openvswitch.git

diff --git a/ovsdb/ovsdb-server.c b/ovsdb/ovsdb-server.c
index 919575a57..a85a672a9 100644
--- a/ovsdb/ovsdb-server.c
+++ b/ovsdb/ovsdb-server.c
@@ -1,4 +1,4 @@
-/* Copyright (c) 2009, 2010, 2011, 2012, 2013 Nicira, Inc.
+/* Copyright (c) 2009, 2010, 2011, 2012, 2013, 2014 Nicira, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -19,6 +19,7 @@
 #include <getopt.h>
 #include <inttypes.h>
 #include <signal.h>
+#include <sys/stat.h>
 #include <unistd.h>
 
 #include "column.h"
@@ -27,6 +28,7 @@
 #include "dirs.h"
 #include "dummy.h"
 #include "dynamic-string.h"
+#include "fatal-signal.h"
 #include "file.h"
 #include "hash.h"
 #include "json.h"
@@ -45,7 +47,6 @@
 #include "shash.h"
 #include "stream-ssl.h"
 #include "stream.h"
-#include "stress.h"
 #include "sset.h"
 #include "table.h"
 #include "timeval.h"
@@ -77,38 +78,42 @@ static unixctl_cb_func ovsdb_server_exit;
 static unixctl_cb_func ovsdb_server_compact;
 static unixctl_cb_func ovsdb_server_reconnect;
 
-struct add_remote_aux {
+struct server_config {
     struct sset *remotes;
     struct shash *all_dbs;
     FILE *config_tmpfile;
+    struct ovsdb_jsonrpc_server *jsonrpc;
 };
 static unixctl_cb_func ovsdb_server_add_remote;
-
-struct remove_remote_aux {
-    struct sset *remotes;
-    FILE *config_tmpfile;
-};
 static unixctl_cb_func ovsdb_server_remove_remote;
 static unixctl_cb_func ovsdb_server_list_remotes;
 
-static void open_db(struct ovsdb_jsonrpc_server *jsonrpc,
-                    struct db *db, struct shash *all_dbs);
+static unixctl_cb_func ovsdb_server_add_database;
+static unixctl_cb_func ovsdb_server_remove_database;
+static unixctl_cb_func ovsdb_server_list_databases;
+
+static char *open_db(struct server_config *config, const char *filename);
 
 static void parse_options(int *argc, char **argvp[],
                           struct sset *remotes, char **unixctl_pathp,
                           char **run_command);
 static void usage(void) NO_RETURN;
 
-static void reconfigure_from_db(struct ovsdb_jsonrpc_server *jsonrpc,
-                                const struct shash *all_dbs,
-                                struct sset *remotes);
+static char *reconfigure_remotes(struct ovsdb_jsonrpc_server *,
+                                 const struct shash *all_dbs,
+                                 struct sset *remotes);
+static char *reconfigure_ssl(const struct shash *all_dbs);
+static void report_error_if_changed(char *error, char **last_errorp);
 
 static void update_remote_status(const struct ovsdb_jsonrpc_server *jsonrpc,
                                  const struct sset *remotes,
                                  struct shash *all_dbs);
 
-static void save_config(FILE *config_file, const struct sset *);
-static void load_config(FILE *config_file, struct sset *);
+static void save_config__(FILE *config_file, const struct sset *remotes,
+                          const struct sset *db_filenames);
+static void save_config(struct server_config *);
+static void load_config(FILE *config_file, struct sset *remotes,
+                        struct sset *db_filenames);
 
 int
 main(int argc, char *argv[])
@@ -117,23 +122,24 @@ main(int argc, char *argv[])
     char *run_command = NULL;
     struct unixctl_server *unixctl;
     struct ovsdb_jsonrpc_server *jsonrpc;
-    struct sset remotes;
+    struct sset remotes, db_filenames;
+    const char *db_filename;
     struct process *run_process;
     bool exiting;
     int retval;
     long long int status_timer = LLONG_MIN;
-    struct add_remote_aux add_remote_aux;
-    struct remove_remote_aux remove_remote_aux;
     FILE *config_tmpfile;
-
+    struct server_config server_config;
     struct shash all_dbs;
     struct shash_node *node;
+    char *remotes_error, *ssl_error;
+    char *error;
     int i;
 
     proctitle_init(argc, argv);
     set_program_name(argv[0]);
-    stress_init_command();
-    signal(SIGPIPE, SIG_IGN);
+    service_start(&argc, &argv);
+    fatal_ignore_sigpipe();
     process_init();
 
     parse_options(&argc, &argv, &remotes, &unixctl_path, &run_command);
@@ -147,29 +153,46 @@ main(int argc, char *argv[])
     if (!config_tmpfile) {
         ovs_fatal(errno, "failed to create temporary file");
     }
-    save_config(config_tmpfile, &remotes);
+
+    sset_init(&db_filenames);
+    if (argc > 0) {
+        for (i = 0; i < argc; i++) {
+            sset_add(&db_filenames, argv[i]);
+         }
+    } else {
+        char *default_db = xasprintf("%s/conf.db", ovs_dbdir());
+        sset_add(&db_filenames, default_db);
+        free(default_db);
+    }
+
+    server_config.remotes = &remotes;
+    server_config.config_tmpfile = config_tmpfile;
+
+    save_config__(config_tmpfile, &remotes, &db_filenames);
 
     daemonize_start();
 
     /* Load the saved config. */
-    load_config(config_tmpfile, &remotes);
-
-    shash_init(&all_dbs);
+    load_config(config_tmpfile, &remotes, &db_filenames);
     jsonrpc = ovsdb_jsonrpc_server_create();
 
-    if (argc > 0) {
-        for (i = 0; i < argc; i++) {
-            struct db *db = xzalloc(sizeof *db);
-            db->filename = argv[i];
-            open_db(jsonrpc, db, &all_dbs);
-         }
-    } else {
-        struct db *db = xzalloc(sizeof *db);
-        db->filename = xasprintf("%s/conf.db", ovs_dbdir());
-        open_db(jsonrpc, db, &all_dbs);
+    shash_init(&all_dbs);
+    server_config.all_dbs = &all_dbs;
+    server_config.jsonrpc = jsonrpc;
+    SSET_FOR_EACH (db_filename, &db_filenames) {
+        error = open_db(&server_config, db_filename);
+        if (error) {
+            ovs_fatal(0, "%s", error);
+        }
     }
 
-    reconfigure_from_db(jsonrpc, &all_dbs, &remotes);
+    error = reconfigure_remotes(jsonrpc, &all_dbs, &remotes);
+    if (!error) {
+        error = reconfigure_ssl(&all_dbs);
+    }
+    if (error) {
+        ovs_fatal(0, "%s", error);
+    }
 
     retval = unixctl_server_create(unixctl_path, &unixctl);
     if (retval) {
@@ -207,21 +230,23 @@ main(int argc, char *argv[])
     unixctl_command_register("ovsdb-server/reconnect", "", 0, 0,
                              ovsdb_server_reconnect, jsonrpc);
 
-    add_remote_aux.remotes = &remotes;
-    add_remote_aux.all_dbs = &all_dbs;
-    add_remote_aux.config_tmpfile = config_tmpfile;
     unixctl_command_register("ovsdb-server/add-remote", "REMOTE", 1, 1,
-                             ovsdb_server_add_remote, &add_remote_aux);
-
-    remove_remote_aux.remotes = &remotes;
-    remove_remote_aux.config_tmpfile = config_tmpfile;
+                             ovsdb_server_add_remote, &server_config);
     unixctl_command_register("ovsdb-server/remove-remote", "REMOTE", 1, 1,
-                             ovsdb_server_remove_remote, &remove_remote_aux);
-
+                             ovsdb_server_remove_remote, &server_config);
     unixctl_command_register("ovsdb-server/list-remotes", "", 0, 0,
                              ovsdb_server_list_remotes, &remotes);
 
+    unixctl_command_register("ovsdb-server/add-db", "DB", 1, 1,
+                             ovsdb_server_add_database, &server_config);
+    unixctl_command_register("ovsdb-server/remove-db", "DB", 1, 1,
+                             ovsdb_server_remove_database, &server_config);
+    unixctl_command_register("ovsdb-server/list-dbs", "", 0, 0,
+                             ovsdb_server_list_databases, &all_dbs);
+
     exiting = false;
+    ssl_error = NULL;
+    remotes_error = NULL;
     while (!exiting) {
         memory_run();
         if (memory_should_report()) {
@@ -237,12 +262,15 @@ main(int argc, char *argv[])
             simap_destroy(&usage);
         }
 
-        /* Run unixctl_server_run() before reconfigure_from_db() because
+        /* Run unixctl_server_run() before reconfigure_remotes() because
          * ovsdb-server/add-remote and ovsdb-server/remove-remote can change
-         * the set of remotes that reconfigure_from_db() uses. */
+         * the set of remotes that reconfigure_remotes() uses. */
         unixctl_server_run(unixctl);
 
-        reconfigure_from_db(jsonrpc, &all_dbs, &remotes);
+        report_error_if_changed(
+            reconfigure_remotes(jsonrpc, &all_dbs, &remotes),
+            &remotes_error);
+        report_error_if_changed(reconfigure_ssl(&all_dbs), &ssl_error);
         ovsdb_jsonrpc_server_run(jsonrpc);
 
         SHASH_FOR_EACH(node, &all_dbs) {
@@ -277,6 +305,9 @@ main(int argc, char *argv[])
         }
         poll_timer_wait_until(status_timer);
         poll_block();
+        if (should_service_stop()) {
+            exiting = true;
+        }
     }
     ovsdb_jsonrpc_server_destroy(jsonrpc);
     SHASH_FOR_EACH(node, &all_dbs) {
@@ -294,27 +325,72 @@ main(int argc, char *argv[])
         }
     }
 
+    service_stop();
     return 0;
 }
 
-static void
-open_db(struct ovsdb_jsonrpc_server *jsonrpc, struct db *db,
-        struct shash *all_dbs)
+/* Returns true if 'filename' is known to be already open as a database,
+ * false if not.
+ *
+ * "False negatives" are possible. */
+static bool
+is_already_open(struct server_config *config OVS_UNUSED,
+                const char *filename OVS_UNUSED)
 {
-    struct ovsdb_error *error;
+#ifndef _WIN32
+    struct stat s;
 
-    error = ovsdb_file_open(db->filename, false,
-                            &db->db, &db->file);
-    if (error) {
-        ovs_fatal(0, "%s", ovsdb_error_to_string(error));
+    if (!stat(filename, &s)) {
+        struct shash_node *node;
+
+        SHASH_FOR_EACH (node, config->all_dbs) {
+            struct db *db = node->data;
+            struct stat s2;
+
+            if (!stat(db->filename, &s2)
+                && s.st_dev == s2.st_dev
+                && s.st_ino == s2.st_ino) {
+                return true;
+            }
+        }
     }
+#endif  /* !_WIN32 */
+
+    return false;
+}
 
-    if (!ovsdb_jsonrpc_server_add_db(jsonrpc, db->db)) {
-        ovs_fatal(0, "%s: duplicate database name",
-                  db->db->schema->name);
+static char *
+open_db(struct server_config *config, const char *filename)
+{
+    struct ovsdb_error *db_error;
+    struct db *db;
+    char *error;
+
+    /* If we know that the file is already open, return a good error message.
+     * Otherwise, if the file is open, we'll fail later on with a harder to
+     * interpret file locking error. */
+    if (is_already_open(config, filename)) {
+        return xasprintf("%s: already open", filename);
+    }
+
+    db = xzalloc(sizeof *db);
+    db->filename = xstrdup(filename);
+
+    db_error = ovsdb_file_open(db->filename, false, &db->db, &db->file);
+    if (db_error) {
+        error = ovsdb_error_to_string(db_error);
+    } else if (!ovsdb_jsonrpc_server_add_db(config->jsonrpc, db->db)) {
+        error = xasprintf("%s: duplicate database name", db->db->schema->name);
+    } else {
+        shash_add_assert(config->all_dbs, db->db->schema->name, db);
+        return NULL;
     }
 
-    shash_add(all_dbs, db->filename, db);
+    ovsdb_error_destroy(db_error);
+    ovsdb_destroy(db->db);
+    free(db->filename);
+    free(db);
+    return error;
 }
 
 static const struct db *
@@ -426,8 +502,9 @@ parse_db_string_column(const struct shash *all_dbs,
     return NULL;
 }
 
-static OVS_UNUSED const char *
-query_db_string(const struct shash *all_dbs, const char *name)
+static const char *
+query_db_string(const struct shash *all_dbs, const char *name,
+                struct ds *errors)
 {
     if (!name || strncmp(name, "db:", 3)) {
         return name;
@@ -441,7 +518,8 @@ query_db_string(const struct shash *all_dbs, const char *name)
         retval = parse_db_string_column(all_dbs, name,
                                         &db, &table, &column);
         if (retval) {
-            ovs_fatal(0, "%s", retval);
+            ds_put_format(errors, "%s\n", retval);
+            return NULL;
         }
 
         HMAP_FOR_EACH (row, hmap_node, &table->rows) {
@@ -496,7 +574,7 @@ get_datum(struct ovsdb_row *row, const char *column_name,
         if (!VLOG_DROP_DBG(&rl)) {
             char *type_name = ovsdb_type_to_english(&column->type);
             VLOG_DBG("Table `%s' column `%s' has type %s, not expected "
-                     "key type %s, value type %s, max elements %zd.",
+                     "key type %s, value type %s, max elements %"PRIuSIZE".",
                      schema->name, column_name, type_name,
                      ovsdb_atomic_type_to_string(key_type),
                      ovsdb_atomic_type_to_string(value_type),
@@ -666,7 +744,7 @@ add_manager_options(struct shash *remotes, const struct ovsdb_row *row)
 
 static void
 query_db_remotes(const char *name, const struct shash *all_dbs,
-                 struct shash *remotes)
+                 struct shash *remotes, struct ds *errors)
 {
     const struct ovsdb_column *column;
     const struct ovsdb_table *table;
@@ -676,7 +754,9 @@ query_db_remotes(const char *name, const struct shash *all_dbs,
 
     retval = parse_db_column(all_dbs, name, &db, &table, &column);
     if (retval) {
-        ovs_fatal(0, "%s", retval);
+        ds_put_format(errors, "%s\n", retval);
+        free(retval);
+        return;
     }
 
     if (column->type.key.type == OVSDB_TYPE_STRING
@@ -791,7 +871,8 @@ update_remote_rows(const struct shash *all_dbs,
 
     retval = parse_db_column(all_dbs, remote_name, &db, &table, &column);
     if (retval) {
-        ovs_fatal(0, "%s", retval);
+        free(retval);
+        return;
     }
 
     if (column->type.key.type != OVSDB_TYPE_UUID
@@ -850,11 +931,12 @@ update_remote_status(const struct ovsdb_jsonrpc_server *jsonrpc,
     }
 }
 
-/* Reconfigures ovsdb-server based on information in the database. */
-static void
-reconfigure_from_db(struct ovsdb_jsonrpc_server *jsonrpc,
+/* Reconfigures ovsdb-server's remotes based on information in the database. */
+static char *
+reconfigure_remotes(struct ovsdb_jsonrpc_server *jsonrpc,
                     const struct shash *all_dbs, struct sset *remotes)
 {
+    struct ds errors = DS_EMPTY_INITIALIZER;
     struct shash resolved_remotes;
     const char *name;
 
@@ -862,7 +944,7 @@ reconfigure_from_db(struct ovsdb_jsonrpc_server *jsonrpc,
     shash_init(&resolved_remotes);
     SSET_FOR_EACH (name, remotes) {
         if (!strncmp(name, "db:", 3)) {
-            query_db_remotes(name, all_dbs, &resolved_remotes);
+            query_db_remotes(name, all_dbs, &resolved_remotes, &errors);
         } else {
             add_remote(&resolved_remotes, name);
         }
@@ -870,11 +952,42 @@ reconfigure_from_db(struct ovsdb_jsonrpc_server *jsonrpc,
     ovsdb_jsonrpc_server_set_remotes(jsonrpc, &resolved_remotes);
     shash_destroy_free_data(&resolved_remotes);
 
-    /* Configure SSL. */
-    stream_ssl_set_key_and_cert(query_db_string(all_dbs, private_key_file),
-                                query_db_string(all_dbs, certificate_file));
-    stream_ssl_set_ca_cert_file(query_db_string(all_dbs, ca_cert_file),
-                                bootstrap_ca_cert);
+    return errors.string;
+}
+
+static char *
+reconfigure_ssl(const struct shash *all_dbs)
+{
+    struct ds errors = DS_EMPTY_INITIALIZER;
+    const char *resolved_private_key;
+    const char *resolved_certificate;
+    const char *resolved_ca_cert;
+
+    resolved_private_key = query_db_string(all_dbs, private_key_file, &errors);
+    resolved_certificate = query_db_string(all_dbs, certificate_file, &errors);
+    resolved_ca_cert = query_db_string(all_dbs, ca_cert_file, &errors);
+
+    stream_ssl_set_key_and_cert(resolved_private_key, resolved_certificate);
+    stream_ssl_set_ca_cert_file(resolved_ca_cert, bootstrap_ca_cert);
+
+    return errors.string;
+}
+
+static void
+report_error_if_changed(char *error, char **last_errorp)
+{
+    if (error) {
+        if (!*last_errorp || strcmp(error, *last_errorp)) {
+            VLOG_WARN("%s", error);
+            free(*last_errorp);
+            *last_errorp = error;
+            return;
+        }
+        free(error);
+    } else {
+        free(*last_errorp);
+        *last_errorp = NULL;
+    }
 }
 
 static void
@@ -914,6 +1027,7 @@ ovsdb_server_compact(struct unixctl_conn *conn, int argc,
                 char *s = ovsdb_error_to_string(error);
                 ds_put_format(&reply, "%s\n", s);
                 free(s);
+                ovsdb_error_destroy(error);
             }
 
             n++;
@@ -946,9 +1060,9 @@ ovsdb_server_reconnect(struct unixctl_conn *conn, int argc OVS_UNUSED,
  * ovsdb-server services. */
 static void
 ovsdb_server_add_remote(struct unixctl_conn *conn, int argc OVS_UNUSED,
-                        const char *argv[], void *aux_)
+                        const char *argv[], void *config_)
 {
-    struct add_remote_aux *aux = aux_;
+    struct server_config *config = config_;
     const char *remote = argv[1];
 
     const struct ovsdb_column *column;
@@ -958,11 +1072,11 @@ ovsdb_server_add_remote(struct unixctl_conn *conn, int argc OVS_UNUSED,
 
     retval = (strncmp("db:", remote, 3)
               ? NULL
-              : parse_db_column(aux->all_dbs, remote,
+              : parse_db_column(config->all_dbs, remote,
                                 &db, &table, &column));
     if (!retval) {
-        if (sset_add(aux->remotes, remote)) {
-            save_config(aux->config_tmpfile, aux->remotes);
+        if (sset_add(config->remotes, remote)) {
+            save_config(config);
         }
         unixctl_command_reply(conn, NULL);
     } else {
@@ -975,15 +1089,15 @@ ovsdb_server_add_remote(struct unixctl_conn *conn, int argc OVS_UNUSED,
  * that ovsdb-server services. */
 static void
 ovsdb_server_remove_remote(struct unixctl_conn *conn, int argc OVS_UNUSED,
-                           const char *argv[], void *aux_)
+                           const char *argv[], void *config_)
 {
-    struct remove_remote_aux *aux = aux_;
+    struct server_config *config = config_;
     struct sset_node *node;
 
-    node = sset_find(aux->remotes, argv[1]);
+    node = sset_find(config->remotes, argv[1]);
     if (node) {
-        sset_delete(aux->remotes, node);
-        save_config(aux->config_tmpfile, aux->remotes);
+        sset_delete(config->remotes, node);
+        save_config(config);
         unixctl_command_reply(conn, NULL);
     } else {
         unixctl_command_reply_error(conn, "no such remote");
@@ -1011,6 +1125,76 @@ ovsdb_server_list_remotes(struct unixctl_conn *conn, int argc OVS_UNUSED,
     ds_destroy(&s);
 }
 
+
+/* "ovsdb-server/add-db DB": adds the DB to ovsdb-server. */
+static void
+ovsdb_server_add_database(struct unixctl_conn *conn, int argc OVS_UNUSED,
+                          const char *argv[], void *config_)
+{
+    struct server_config *config = config_;
+    const char *filename = argv[1];
+    char *error;
+
+    error = open_db(config, filename);
+    if (!error) {
+        save_config(config);
+        unixctl_command_reply(conn, NULL);
+    } else {
+        unixctl_command_reply_error(conn, error);
+        free(error);
+    }
+}
+
+static void
+ovsdb_server_remove_database(struct unixctl_conn *conn, int argc OVS_UNUSED,
+                             const char *argv[], void *config_)
+{
+    struct server_config *config = config_;
+    struct shash_node *node;
+    struct db *db;
+    bool ok;
+
+    node = shash_find(config->all_dbs, argv[1]);
+    if (!node)  {
+        unixctl_command_reply_error(conn, "Failed to find the database.");
+        return;
+    }
+    db = node->data;
+
+    ok = ovsdb_jsonrpc_server_remove_db(config->jsonrpc, db->db);
+    ovs_assert(ok);
+
+    ovsdb_destroy(db->db);
+    shash_delete(config->all_dbs, node);
+    free(db->filename);
+    free(db);
+
+    save_config(config);
+    unixctl_command_reply(conn, NULL);
+}
+
+static void
+ovsdb_server_list_databases(struct unixctl_conn *conn, int argc OVS_UNUSED,
+                            const char *argv[] OVS_UNUSED, void *all_dbs_)
+{
+    struct shash *all_dbs = all_dbs_;
+    const struct shash_node **nodes;
+    struct ds s;
+    size_t i;
+
+    ds_init(&s);
+
+    nodes = shash_sort(all_dbs);
+    for (i = 0; i < shash_count(all_dbs); i++) {
+        struct db *db = nodes[i]->data;
+        ds_put_format(&s, "%s\n", db->db->schema->name);
+    }
+    free(nodes);
+
+    unixctl_command_reply(conn, ds_cstr(&s));
+    ds_destroy(&s);
+}
+
 static void
 parse_options(int *argcp, char **argvp[],
               struct sset *remotes, char **unixctl_pathp, char **run_command)
@@ -1027,7 +1211,9 @@ parse_options(int *argcp, char **argvp[],
     static const struct option long_options[] = {
         {"remote",      required_argument, NULL, OPT_REMOTE},
         {"unixctl",     required_argument, NULL, OPT_UNIXCTL},
+#ifndef _WIN32
         {"run",         required_argument, NULL, OPT_RUN},
+#endif
         {"help",        no_argument, NULL, 'h'},
         {"version",     no_argument, NULL, 'V'},
         DAEMON_LONG_OPTIONS,
@@ -1131,55 +1317,98 @@ usage(void)
     exit(EXIT_SUCCESS);
 }
 
-/* Truncates and replaces the contents of 'config_file' by a representation
- * of 'remotes'. */
+static struct json *
+sset_to_json(const struct sset *sset)
+{
+    struct json *array;
+    const char *s;
+
+    array = json_array_create_empty();
+    SSET_FOR_EACH (s, sset) {
+        json_array_add(array, json_string_create(s));
+    }
+    return array;
+}
+
+/* Truncates and replaces the contents of 'config_file' by a representation of
+ * 'remotes' and 'db_filenames'. */
 static void
-save_config(FILE *config_file, const struct sset *remotes)
+save_config__(FILE *config_file, const struct sset *remotes,
+              const struct sset *db_filenames)
 {
-    const char *remote;
-    struct json *json;
+    struct json *obj;
     char *s;
 
     if (ftruncate(fileno(config_file), 0) == -1) {
-        VLOG_FATAL("failed to truncate temporary file (%s)", strerror(errno));
+        VLOG_FATAL("failed to truncate temporary file (%s)",
+                   ovs_strerror(errno));
     }
 
-    json = json_array_create_empty();
-    SSET_FOR_EACH (remote, remotes) {
-        json_array_add(json, json_string_create(remote));
-    }
-    s = json_to_string(json, 0);
-    json_destroy(json);
+    obj = json_object_create();
+    json_object_put(obj, "remotes", sset_to_json(remotes));
+    json_object_put(obj, "db_filenames", sset_to_json(db_filenames));
+    s = json_to_string(obj, 0);
+    json_destroy(obj);
 
     if (fseek(config_file, 0, SEEK_SET) != 0
         || fputs(s, config_file) == EOF
         || fflush(config_file) == EOF) {
-        VLOG_FATAL("failed to write temporary file (%s)", strerror(errno));
+        VLOG_FATAL("failed to write temporary file (%s)", ovs_strerror(errno));
     }
     free(s);
 }
 
-/* Clears and replaces 'remotes' by a configuration read from 'config_file',
- * which must have been previously written by save_config(). */
+/* Truncates and replaces the contents of 'config_file' by a representation of
+ * 'config'. */
 static void
-load_config(FILE *config_file, struct sset *remotes)
+save_config(struct server_config *config)
+{
+    struct sset db_filenames;
+    struct shash_node *node;
+
+    sset_init(&db_filenames);
+    SHASH_FOR_EACH (node, config->all_dbs) {
+        struct db *db = node->data;
+        sset_add(&db_filenames, db->filename);
+    }
+
+    save_config__(config->config_tmpfile, config->remotes, &db_filenames);
+
+    sset_destroy(&db_filenames);
+}
+
+static void
+sset_from_json(struct sset *sset, const struct json *array)
 {
-    struct json *json;
     size_t i;
 
-    sset_clear(remotes);
+    sset_clear(sset);
+
+    ovs_assert(array->type == JSON_ARRAY);
+    for (i = 0; i < array->u.array.n; i++) {
+        const struct json *elem = array->u.array.elems[i];
+        sset_add(sset, json_string(elem));
+    }
+}
+
+/* Clears and replaces 'remotes' and 'dbnames' by a configuration read from
+ * 'config_file', which must have been previously written by save_config(). */
+static void
+load_config(FILE *config_file, struct sset *remotes, struct sset *db_filenames)
+{
+    struct json *json;
 
     if (fseek(config_file, 0, SEEK_SET) != 0) {
-        VLOG_FATAL("seek failed in temporary file (%s)", strerror(errno));
+        VLOG_FATAL("seek failed in temporary file (%s)", ovs_strerror(errno));
     }
     json = json_from_stream(config_file);
     if (json->type == JSON_STRING) {
         VLOG_FATAL("reading json failed (%s)", json_string(json));
     }
-    ovs_assert(json->type == JSON_ARRAY);
-    for (i = 0; i < json->u.array.n; i++) {
-        const struct json *remote = json->u.array.elems[i];
-        sset_add(remotes, json_string(remote));
-    }
+    ovs_assert(json->type == JSON_OBJECT);
+
+    sset_from_json(remotes, shash_find_data(json_object(json), "remotes"));
+    sset_from_json(db_filenames,
+                   shash_find_data(json_object(json), "db_filenames"));
     json_destroy(json);
 }