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/nfsdcld/Makefile.am | 4 +-
utils/nfsdcld/nfsdcld.c | 16 ++-
utils/nfsdcld/sqlite.c | 256 +++++++++++++++++++++++++++++++++++++++++++++
utils/nfsdcld/sqlite.h | 27 +++++
4 files changed, 297 insertions(+), 6 deletions(-)
create mode 100644 utils/nfsdcld/sqlite.c
create mode 100644 utils/nfsdcld/sqlite.h
diff --git a/utils/nfsdcld/Makefile.am b/utils/nfsdcld/Makefile.am
index ed7ed42..8e4f2ab 100644
--- a/utils/nfsdcld/Makefile.am
+++ b/utils/nfsdcld/Makefile.am
@@ -6,9 +6,9 @@
AM_CFLAGS += -D_LARGEFILE64_SOURCE
sbin_PROGRAMS = nfsdcld
-nfsdcld_SOURCES = nfsdcld.c
+nfsdcld_SOURCES = nfsdcld.c sqlite.c
-nfsdcld_LDADD = ../../support/nfs/libnfs.a $(LIBEVENT)
+nfsdcld_LDADD = ../../support/nfs/libnfs.a $(LIBEVENT) $(LIBSQLITE)
MAINTAINERCLEANFILES = Makefile.in
diff --git a/utils/nfsdcld/nfsdcld.c b/utils/nfsdcld/nfsdcld.c
index d82908f..de2e932 100644
--- a/utils/nfsdcld/nfsdcld.c
+++ b/utils/nfsdcld/nfsdcld.c
@@ -36,6 +36,7 @@
#include "xlog.h"
#include "nfslib.h"
+#include "sqlite.h"
#ifndef PIPEFS_DIR
#define PIPEFS_DIR NFS_STATEDIR "/rpc_pipefs"
@@ -111,18 +112,20 @@ cld_pipe_reopen(struct cld_client *clnt)
static void
cld_create(struct cld_client *clnt)
{
+ int ret;
ssize_t bsize, wsize;
struct cld_msg *cmsg = &clnt->cl_msg;
- xlog(D_GENERAL, "%s: create client record", __func__);
+ xlog(D_GENERAL, "%s: create client record.", __func__);
- /* FIXME: create client record on storage here */
+ ret = sqlite_insert_client(cmsg->cm_u.cm_name.cn_id,
+ cmsg->cm_u.cm_name.cn_len);
- /* set up reply */
- cmsg->cm_status = 0;
+ cmsg->cm_status = ret ? -EREMOTEIO : ret;
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 cld pipe (%ld): %m",
@@ -221,6 +224,11 @@ main(int argc, char **argv)
}
/* set up storage db */
+ rc = sqlite_maindb_init();
+ if (rc) {
+ xlog(L_ERROR, "Failed to open main database: %d", rc);
+ goto out;
+ }
/* set up event handler */
fd = cld_pipe_open(&clnt);
diff --git a/utils/nfsdcld/sqlite.c b/utils/nfsdcld/sqlite.c
new file mode 100644
index 0000000..2534ba5
--- /dev/null
+++ b/utils/nfsdcld/sqlite.c
@@ -0,0 +1,256 @@
+/*
+ * 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
+ *
+ * clients: one column containing a BLOB with the 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 "xlog.h"
+
+#define CLD_SQLITE_SCHEMA_VERSION 1
+
+#ifndef CLD_SQLITE_TOPDIR
+#define CLD_SQLITE_TOPDIR NFS_STATEDIR "/nfsdcld"
+#endif
+
+/* in milliseconds */
+#define CLD_SQLITE_BUSY_TIMEOUT 10000
+
+/* private data structures */
+
+/* global variables */
+
+/* top level DB directory */
+static char *sqlite_topdir = CLD_SQLITE_TOPDIR;
+
+/* reusable pathname and sql command buffer */
+static char buf[PATH_MAX];
+
+/* global database handle */
+static sqlite3 *dbh;
+
+/* forward declarations */
+
+void
+sqlite_set_topdir(char *topdir)
+{
+ sqlite_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. If all of that works, then attempt to create
+ * the "clients" table.
+ */
+int
+sqlite_maindb_init(void)
+{
+ int ret;
+ char *err = NULL;
+ sqlite3_stmt *stmt = NULL;
+
+ ret = mkdir_if_not_exist(sqlite_topdir);
+ if (ret)
+ return ret;
+
+ ret = snprintf(buf, PATH_MAX - 1, "%s/main.sqlite", sqlite_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, CLD_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\");", CLD_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 != CLD_SQLITE_SCHEMA_VERSION) {
+ xlog(L_ERROR, "Unsupported database schema version! "
+ "Expected %d, got %d.",
+ CLD_SQLITE_SCHEMA_VERSION, ret);
+ ret = -EINVAL;
+ goto out_err;
+ }
+
+ /* now create the "clients" table */
+ ret = sqlite3_exec(dbh, "CREATE TABLE IF NOT EXISTS clients "
+ "(id BLOB PRIMARY KEY, time INTEGER);",
+ NULL, NULL, &err);
+ if (ret != SQLITE_OK) {
+ xlog(L_ERROR, "Unable to create clients table: %s", err);
+ 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;
+}
+
+/*
+ * Create a client record
+ *
+ * Returns a non-zero sqlite error code, or SQLITE_OK (aka 0)
+ */
+int
+sqlite_insert_client(const unsigned char *clname, const size_t namelen)
+{
+ int ret;
+ sqlite3_stmt *stmt = NULL;
+
+ ret = sqlite3_prepare_v2(dbh, "INSERT OR REPLACE INTO clients VALUES "
+ "(?, strftime('%s', 'now'));", -1,
+ &stmt, NULL);
+ if (ret != SQLITE_OK) {
+ xlog(D_GENERAL, "Insert statement prepare failed: %s",
+ sqlite3_errmsg(dbh));
+ return ret;
+ }
+
+ ret = sqlite3_bind_blob(stmt, 1, (const void *)clname, namelen,
+ SQLITE_STATIC);
+ if (ret != SQLITE_OK) {
+ xlog(D_GENERAL, "Bind blob failed: %d", sqlite3_errmsg(dbh));
+ 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);
+ return ret;
+}
diff --git a/utils/nfsdcld/sqlite.h b/utils/nfsdcld/sqlite.h
new file mode 100644
index 0000000..4b99729
--- /dev/null
+++ b/utils/nfsdcld/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 sqlite_set_topdir(char *topdir);
+int sqlite_maindb_init(void);
+int sqlite_insert_client(const unsigned char *clname, const size_t namelen);
+
+#endif /* _SQLITE_H */
--
1.7.1
--
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