Rather than roll our own "storage engine", use sqlite instead. It fits
the bill nicely as it does:
- durable on-disk storage
- the ability to constrain record uniqueness
- a facility for collating and searching the host records
...it does add a build dependency to nfs-utils, but almost all modern
distros provide those packages.
The current incarnation of this code dynamically links against a
provided sqlite library, but we could also consider including their
single-file "amalgamation" to reduce dependencies (though with all
the caveats that that entails).
Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
---
utils/clstated/Makefile.am | 4 +-
utils/clstated/clstated.c | 16 ++-
utils/clstated/sqlite.c | 351 ++++++++++++++++++++++++++++++++++++++++++++
utils/clstated/sqlite.h | 27 ++++
4 files changed, 393 insertions(+), 5 deletions(-)
create mode 100644 utils/clstated/sqlite.c
create mode 100644 utils/clstated/sqlite.h
diff --git a/utils/clstated/Makefile.am b/utils/clstated/Makefile.am
index 9937353..d1cef3c 100644
--- a/utils/clstated/Makefile.am
+++ b/utils/clstated/Makefile.am
@@ -6,9 +6,9 @@
AM_CFLAGS += -D_LARGEFILE64_SOURCE
sbin_PROGRAMS = clstated
-clstated_SOURCES = clstated.c
+clstated_SOURCES = clstated.c sqlite.c
-clstated_LDADD = ../../support/nfs/libnfs.a $(LIBEVENT)
+clstated_LDADD = ../../support/nfs/libnfs.a $(LIBEVENT) $(LIBSQLITE)
MAINTAINERCLEANFILES = Makefile.in
diff --git a/utils/clstated/clstated.c b/utils/clstated/clstated.c
index aab09a7..95ac696 100644
--- a/utils/clstated/clstated.c
+++ b/utils/clstated/clstated.c
@@ -36,6 +36,7 @@
#include "xlog.h"
#include "nfslib.h"
+#include "sqlite.h"
#ifndef PIPEFS_DIR
#define PIPEFS_DIR NFS_STATEDIR "/rpc_pipefs"
@@ -118,21 +119,25 @@ clstate_pipe_reopen(struct clstate_client *clnt)
static void
clstate_create(struct clstate_client *clnt)
{
+ int ret;
ssize_t bsize, wsize;
struct clstate_msg *cmsg = &clnt->cl_msg;
- xlog(D_GENERAL, "%s: create client record", __func__);
+ xlog(D_GENERAL, "%s: create client record. cm_addr=%s", __func__,
+ cmsg->cm_addr);
- /* FIXME: create client record on storage here */
+ ret = clstate_insert_client(cmsg->cm_addr, cmsg->cm_u.cm_id,
+ cmsg->cm_len);
/* set up reply */
- cmsg->cm_status = 0;
+ cmsg->cm_status = ret ? -EREMOTEIO : ret;
cmsg->cm_len = 0;
memset(cmsg->cm_addr, 0, sizeof(cmsg->cm_addr) +
sizeof(cmsg->cm_u.cm_id));
bsize = sizeof(*cmsg);
+ xlog(D_GENERAL, "Doing downcall with status %d", cmsg->cm_status);
wsize = atomicio((void *)write, clnt->cl_fd, cmsg, bsize);
if (wsize != bsize) {
xlog(L_ERROR, "%s: problem writing to clstate pipe (%ld): %m",
@@ -231,6 +236,11 @@ main(int argc, char **argv)
}
/* set up storage db */
+ rc = clstate_maindb_init();
+ if (rc) {
+ xlog(L_ERROR, "Failed to open main database: %d", rc);
+ goto out;
+ }
/* set up event handler */
fd = clstate_pipe_open(&clnt);
diff --git a/utils/clstated/sqlite.c b/utils/clstated/sqlite.c
new file mode 100644
index 0000000..ae83634
--- /dev/null
+++ b/utils/clstated/sqlite.c
@@ -0,0 +1,351 @@
+/*
+ * Copyright (C) 2011 Red Hat, Jeff Layton <jlayton@xxxxxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ * Boston, MA 02110-1301, USA.
+ */
+
+/*
+ * Explanation:
+ *
+ * This file contains the code to manage the sqlite backend database for the
+ * clstated upcall daemon.
+ *
+ * The main database is called main.sqlite and contains the following tables:
+ *
+ * parameters: simple key/value pairs for storing database info
+ *
+ * addresses: list of server-side addresses recorded in the db, along with
+ * the filenames of their respective db files.
+ *
+ * The daemon attaches to each server-address database as needed. Each
+ * server-address database has the following tables:
+ *
+ * clients: one column containing a BLOB with the clstate as sent by the client
+ * and a timestamp (in epoch seconds) of when the record was
+ * established
+ *
+ * FIXME: should we also record the fsid being accessed?
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif /* HAVE_CONFIG_H */
+
+#include <errno.h>
+#include <event.h>
+#include <stdbool.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <sqlite3.h>
+#include <linux/limits.h>
+#include <linux/nfsd/clstate.h>
+
+#include "xlog.h"
+
+#define CLSTATE_SQLITE_SCHEMA_VERSION 1
+
+#ifndef CLSTATE_DIR
+#define CLSTATE_DIR NFS_STATEDIR "/clstate"
+#endif
+
+/* in milliseconds */
+#define CLSTATE_SQLITE_BUSY_TIMEOUT 10000
+
+/* private data structures */
+
+/* global variables */
+
+/* top level DB directory */
+static char *clstate_topdir = CLSTATE_DIR;
+
+/* reusable pathname and sql command buffer */
+static char buf[PATH_MAX];
+
+/* global database handle */
+static sqlite3 *dbh;
+
+/* forward declarations */
+
+/* '.' is not allowed in dbnames -- convert them to '-' */
+static void
+addr_to_dbname(const char *src, char *dst)
+{
+ while(*src) {
+ if (*src == '.')
+ *dst = '-';
+ else
+ *dst = *src;
+ ++src;
+ ++dst;
+ }
+ *dst = '\0';
+}
+
+void
+clstate_set_topdir(char *topdir)
+{
+ clstate_topdir = topdir;
+}
+
+/* make a directory, ignoring EEXIST errors unless it's not a directory */
+static int
+mkdir_if_not_exist(char *dirname)
+{
+ int ret;
+ struct stat statbuf;
+
+ ret = mkdir(dirname, S_IRWXU);
+ if (ret && errno != EEXIST)
+ return -errno;
+
+ ret = stat(dirname, &statbuf);
+ if (ret)
+ return -errno;
+
+ if (!S_ISDIR(statbuf.st_mode))
+ ret = -ENOTDIR;
+
+ return ret;
+}
+
+/*
+ * Open the "main" database, and attempt to initialize it by creating the
+ * parameters table and inserting the schema version into it. Ignore any errors
+ * from that, and then attempt to select the version out of it again. If the
+ * version appears wrong, then assume that the DB is corrupt or has been
+ * upgraded, and return an error.
+ */
+int
+clstate_maindb_init(void)
+{
+ int ret;
+ char *err = NULL;
+ sqlite3_stmt *stmt = NULL;
+
+ ret = mkdir_if_not_exist(clstate_topdir);
+ if (ret)
+ return ret;
+
+ ret = snprintf(buf, PATH_MAX - 1, "%s/main.sqlite", clstate_topdir);
+ if (ret < 0)
+ return ret;
+
+ buf[PATH_MAX - 1] = '\0';
+
+ ret = sqlite3_open(buf, &dbh);
+ if (ret != SQLITE_OK) {
+ xlog(D_GENERAL, "Unable to open main database: %d", ret);
+ return ret;
+ }
+
+ ret = sqlite3_busy_timeout(dbh, CLSTATE_SQLITE_BUSY_TIMEOUT);
+ if (ret != SQLITE_OK) {
+ xlog(D_GENERAL, "Unable to set sqlite busy timeout: %d", ret);
+ goto out_err;
+ }
+
+ /* Try to create table */
+ ret = sqlite3_exec(dbh, "CREATE TABLE IF NOT EXISTS parameters "
+ "(key TEXT PRIMARY KEY, value TEXT);",
+ NULL, NULL, &err);
+ if (ret != SQLITE_OK) {
+ xlog(D_GENERAL, "Unable to create parameter table: %d", ret);
+ goto out_err;
+ }
+
+ /* insert version into table -- ignore error if it fails */
+ ret = snprintf(buf, sizeof(buf),
+ "INSERT OR IGNORE INTO parameters values (\"version\", "
+ "\"%d\");", CLSTATE_SQLITE_SCHEMA_VERSION);
+ if (ret < 0) {
+ goto out_err;
+ } else if ((size_t)ret >= sizeof(buf)) {
+ ret = -EINVAL;
+ goto out_err;
+ }
+
+ ret = sqlite3_exec(dbh, (const char *)buf, NULL, NULL, &err);
+ if (ret != SQLITE_OK) {
+ xlog(D_GENERAL, "Unable to insert into parameter table: %d",
+ ret);
+ goto out_err;
+ }
+
+ ret = sqlite3_prepare_v2(dbh,
+ "SELECT value FROM parameters WHERE key == \"version\";",
+ -1, &stmt, NULL);
+ if (ret != SQLITE_OK) {
+ xlog(D_GENERAL, "Unable to prepare select statement: %d", ret);
+ goto out_err;
+ }
+
+ /* check schema version */
+ ret = sqlite3_step(stmt);
+ if (ret != SQLITE_ROW) {
+ xlog(D_GENERAL, "Select statement execution failed: %s",
+ sqlite3_errmsg(dbh));
+ goto out_err;
+ }
+
+ /* process SELECT result */
+ ret = sqlite3_column_int(stmt, 0);
+ if (ret != CLSTATE_SQLITE_SCHEMA_VERSION) {
+ xlog(L_ERROR, "Unsupported database schema version! "
+ "Expected %d, got %d.",
+ CLSTATE_SQLITE_SCHEMA_VERSION, ret);
+ ret = -EINVAL;
+ goto out_err;
+ }
+
+ sqlite3_free(err);
+ sqlite3_finalize(stmt);
+ return 0;
+
+out_err:
+ if (err) {
+ xlog(L_ERROR, "sqlite error: %s", err);
+ sqlite3_free(err);
+ }
+ sqlite3_finalize(stmt);
+ sqlite3_close(dbh);
+ return ret;
+}
+
+static int
+clstate_db_attach(char *dbname)
+{
+ int ret;
+ char *err;
+
+ /* convert address string into valid filename */
+ ret = snprintf(buf, sizeof(buf),
+ "ATTACH DATABASE \"%s/%s.sqlite\" as \"%s\";",
+ clstate_topdir, dbname, dbname);
+ if (ret < 0) {
+ return ret;
+ } else if ((size_t)ret >= sizeof(buf)) {
+ ret = -EINVAL;
+ return ret;
+ }
+
+ /* attach to new DB in filename */
+ ret = sqlite3_exec(dbh, buf, NULL, NULL, &err);
+ if (ret != SQLITE_OK)
+ xlog(L_ERROR, "Unable to attach database %s: %s", dbname, err);
+
+ xlog(D_GENERAL, "Attached database %s", dbname);
+ return ret;
+}
+
+static int
+clstate_db_detach(char *dbname)
+{
+ int ret;
+ char *err;
+
+ /* convert address string into valid filename */
+ ret = snprintf(buf, PATH_MAX - 1, "DETACH DATABASE \"%s\";", dbname);
+ if (ret < 0) {
+ return ret;
+ } else if ((size_t)ret >= sizeof(buf)) {
+ ret = -EINVAL;
+ return ret;
+ }
+
+ /* attach to new DB in filename */
+ ret = sqlite3_exec(dbh, buf, NULL, NULL, &err);
+ if (ret != SQLITE_OK)
+ xlog(L_ERROR, "Unable to detach database %s: %s", dbname, err);
+
+ xlog(D_GENERAL, "Detached database %s", dbname);
+ return ret;
+}
+
+/*
+ * Create a client record
+ */
+int
+clstate_insert_client(const unsigned char *addr, const unsigned char *clname,
+ const size_t namelen)
+{
+ int ret;
+ char *err = NULL;
+ char dbname[CLSTATE_MAX_ADDRESS_LEN];
+ sqlite3_stmt *stmt = NULL;
+
+ addr_to_dbname((const char *)addr, dbname);
+
+ ret = clstate_db_attach(dbname);
+ if (ret != SQLITE_OK)
+ return ret;
+
+ snprintf(buf, sizeof(buf), "CREATE TABLE IF NOT EXISTS '%s'.clients "
+ "(id BLOB PRIMARY KEY, time INTEGER);",
+ dbname);
+ if (ret < 0) {
+ goto out_detach;
+ } else if ((size_t)ret >= sizeof(buf)) {
+ ret = -EINVAL;
+ goto out_detach;
+ }
+
+ ret = sqlite3_exec(dbh, buf, NULL, NULL, &err);
+ if (ret != SQLITE_OK) {
+ xlog(L_ERROR, "Unable to create table: %s", err);
+ goto out_detach;
+ }
+
+ ret = snprintf(buf, sizeof(buf),
+ "INSERT OR REPLACE INTO '%s'.clients VALUES (?, "
+ "strftime('%%s', 'now'));", dbname);
+ if (ret < 0) {
+ goto out_detach;
+ } else if ((size_t)ret >= sizeof(buf)) {
+ ret = -EINVAL;
+ goto out_detach;
+ }
+
+ ret = sqlite3_prepare_v2(dbh, buf, ret + 1, &stmt, NULL);
+ if (ret != SQLITE_OK) {
+ xlog(D_GENERAL, "Statement prepare failed: %d", ret);
+ goto out_err;
+ }
+
+ ret = sqlite3_bind_blob(stmt, 1, (const void *)clname, namelen,
+ SQLITE_STATIC);
+ if (ret != SQLITE_OK) {
+ xlog(D_GENERAL, "Bind blob failed: %d", ret);
+ goto out_err;
+ }
+
+ ret = sqlite3_step(stmt);
+ if (ret == SQLITE_DONE)
+ ret = SQLITE_OK;
+ else
+ xlog(D_GENERAL, "Unexpected return code from insert: %s",
+ sqlite3_errmsg(dbh));
+
+out_err:
+ xlog(D_GENERAL, "%s returning %d", __func__, ret);
+ sqlite3_finalize(stmt);
+ sqlite3_free(err);
+out_detach:
+ clstate_db_detach(dbname);
+ return ret;
+}
diff --git a/utils/clstated/sqlite.h b/utils/clstated/sqlite.h
new file mode 100644
index 0000000..4f81745
--- /dev/null
+++ b/utils/clstated/sqlite.h
@@ -0,0 +1,27 @@
+/*
+ * Copyright (C) 2011 Red Hat, Jeff Layton <jlayton@xxxxxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#ifndef _SQLITE_H_
+#define _SQLITE_H_
+
+void clstate_set_topdir(char *topdir);
+int clstate_maindb_init(void);
+int clstate_insert_client(const unsigned char *addr, const unsigned char *clname, const size_t namelen);
+
+#endif /* _SQLITE_H */
--
1.7.1
--
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