dbi plugin: Add a plugin to query databases.

The plugin uses the `dbi' library which provides a database independent
interface. It has only been tested with MySQL so far, so ymmv.

The configuration is similar to the PostgreSQL plugin: You define
queries and databases which execute those queries every $interval
seconds.

diff --git a/configure.in b/configure.in
index a62f8a09203df2e91066ed04c05e1832a2877269..ffaacc3c306ba3c75064913927d2cffb7c07f3d6 100644 (file)
--- a/configure.in
+++ b/configure.in
@@ -1056,6 +1056,56 @@ fi
 AM_CONDITIONAL(BUILD_WITH_LIBCURL, test "x$with_libcurl" = "xyes")
 # }}}
 
+# --with-libdbi {{{
+with_libdbi_cppflags=""
+with_libdbi_ldflags=""
+AC_ARG_WITH(libdbi, [AS_HELP_STRING([--with-libdbi@<:@=PREFIX@:>@], [Path to libdbi.])],
+[
+       if test "x$withval" != "xno" && test "x$withval" != "xyes"
+       then
+               with_libdbi_cppflags="-I$withval/include"
+               with_libdbi_ldflags="-L$withval/lib"
+               with_libdbi="yes"
+       else
+               with_libdbi="$withval"
+       fi
+],
+[
+       with_libdbi="yes"
+])
+if test "x$with_libdbi" = "xyes"
+then
+       SAVE_CPPFLAGS="$CPPFLAGS"
+       CPPFLAGS="$CPPFLAGS $with_libdbi_cppflags"
+
+       AC_CHECK_HEADERS(dbi/dbi.h, [with_libdbi="yes"], [with_libdbi="no (dbi/dbi.h not found)"])
+
+       CPPFLAGS="$SAVE_CPPFLAGS"
+fi
+if test "x$with_libdbi" = "xyes"
+then
+       SAVE_CPPFLAGS="$CPPFLAGS"
+       SAVE_LDFLAGS="$LDFLAGS"
+       CPPFLAGS="$CPPFLAGS $with_libdbi_cppflags"
+       LDFLAGS="$LDFLAGS $with_libdbi_ldflags"
+
+       AC_CHECK_LIB(dbi, dbi_initialize, [with_libdbi="yes"], [with_libdbi="no (Symbol 'dbi_initialize' not found)"])
+
+       CPPFLAGS="$SAVE_CPPFLAGS"
+       LDFLAGS="$SAVE_LDFLAGS"
+fi
+if test "x$with_libdbi" = "xyes"
+then
+       BUILD_WITH_LIBDBI_CPPFLAGS="$with_libdbi_cppflags"
+       BUILD_WITH_LIBDBI_LDFLAGS="$with_libdbi_ldflags"
+       BUILD_WITH_LIBDBI_LIBS="-ldbi"
+       AC_SUBST(BUILD_WITH_LIBDBI_CPPFLAGS)
+       AC_SUBST(BUILD_WITH_LIBDBI_LDFLAGS)
+       AC_SUBST(BUILD_WITH_LIBDBI_LIBS)
+fi
+AM_CONDITIONAL(BUILD_WITH_LIBDBI, test "x$with_libdbi" = "xyes")
+# }}}
+
 # --with-libesmtp {{{
 AC_ARG_WITH(libesmtp, [AS_HELP_STRING([--with-libesmtp@<:@=PREFIX@:>@], [Path to libesmtp.])],
 [
@@ -2726,6 +2776,7 @@ AC_PLUGIN([cpu],         [$plugin_cpu],        [CPU usage statistics])
 AC_PLUGIN([cpufreq],     [$plugin_cpufreq],    [CPU frequency statistics])
 AC_PLUGIN([csv],         [yes],                [CSV output plugin])
 AC_PLUGIN([notify_desktop], [$with_libnotify], [Desktop notifications])
+AC_PLUGIN([dbi],         [$with_libdbi],       [General database statistics])
 AC_PLUGIN([df],          [$plugin_df],         [Filesystem usage statistics])
 AC_PLUGIN([disk],        [$plugin_disk],       [Disk usage statistics])
 AC_PLUGIN([dns],         [$with_libpcap],      [DNS traffic analysis])
@@ -2854,6 +2905,7 @@ cat <<EOF;
 Configuration:
   Libraries:
     libcurl . . . . . . . $with_libcurl
+    libdbi  . . . . . . . $with_libdbi
     libesmtp  . . . . . . $with_libesmtp
     libiokit  . . . . . . $with_libiokit
     libiptc . . . . . . . $with_libiptc
@@ -2894,6 +2946,7 @@ Configuration:
     cpu . . . . . . . . . $enable_cpu
     cpufreq . . . . . . . $enable_cpufreq
     csv . . . . . . . . . $enable_csv
+    dbi . . . . . . . . . $enable_dbi
     df  . . . . . . . . . $enable_df
     disk  . . . . . . . . $enable_disk
     dns . . . . . . . . . $enable_dns

diff --git a/src/Makefile.am b/src/Makefile.am
index 4412b3b20c4c54d6f26a4414ea34f7cc9fa7fcd8..b9b7ab89b3dbf1dc6e732ef6059ce9b008eb01bc 100644 (file)
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -184,6 +184,16 @@ collectd_LDADD += "-dlopen" csv.la
 collectd_DEPENDENCIES += csv.la
 endif
 
+if BUILD_PLUGIN_DBI
+pkglib_LTLIBRARIES += dbi.la
+dbi_la_SOURCES = dbi.c
+dbi_la_CPPFLAGS = $(AM_CPPFLAGS) $(BUILD_WITH_LIBDBI_CPPFLAGS)
+dbi_la_LDFLAGS = -module -avoid-version $(BUILD_WITH_LIBDBI_LDFLAGS)
+dbi_la_LIBADD = $(BUILD_WITH_LIBDBI_LIBS)
+collectd_LDADD += "-dlopen" dbi.la
+collectd_DEPENDENCIES += dbi.la
+endif
+
 if BUILD_PLUGIN_DF
 pkglib_LTLIBRARIES += df.la
 df_la_SOURCES = df.c

diff --git a/src/dbi.c b/src/dbi.c
new file mode 100644 (file)
index 0000000..484c604
--- /dev/null
+++ b/src/dbi.c
@@ -0,0 +1,1059 @@
+/**
+ * collectd - src/dbi.c
+ * Copyright (C) 2008  Florian octo Forster
+ *
+ * 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; only version 2 of the License is applicable.
+ *
+ * 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 St, Fifth Floor, Boston, MA  02110-1301 USA
+ *
+ * Authors:
+ *   Florian octo Forster <octo at verplant.org>
+ **/
+
+#include "collectd.h"
+#include "common.h"
+#include "plugin.h"
+#include "configfile.h"
+
+#include <dbi/dbi.h>
+
+/*
+ * Data types
+ */
+struct cdbi_driver_option_s
+{
+  char *key;
+  char *value;
+};
+typedef struct cdbi_driver_option_s cdbi_driver_option_t;
+
+struct cdbi_query_s
+{
+  char    *name;
+  char    *statement;
+  char    *type;
+  char   **instances;
+  size_t   instances_num;
+  char   **values;
+  size_t   values_num;
+};
+typedef struct cdbi_query_s cdbi_query_t;
+
+struct cdbi_database_s
+{
+  char *name;
+  char *select_db;
+
+  char *driver;
+  cdbi_driver_option_t *driver_options;
+  size_t driver_options_num;
+
+  cdbi_query_t **queries;
+  size_t      queries_num;
+
+  dbi_conn connection;
+};
+typedef struct cdbi_database_s cdbi_database_t;
+
+/*
+ * Global variables
+ */
+static cdbi_query_t    **queries       = NULL;
+static size_t         queries_num   = 0;
+static cdbi_database_t **databases     = NULL;
+static size_t         databases_num = 0;
+
+/*
+ * Functions
+ */
+static const char *cdbi_strerror (dbi_conn conn, /* {{{ */
+    char *buffer, size_t buffer_size)
+{
+  const char *msg;
+  int status;
+
+  if (conn == NULL)
+  {
+    sstrncpy (buffer, "connection is NULL", buffer_size);
+    return (buffer);
+  }
+
+  msg = NULL;
+  status = dbi_conn_error (conn, &msg);
+  if ((status >= 0) && (msg != NULL))
+    ssnprintf (buffer, buffer_size, "%s (status %i)", msg, status);
+  else
+    ssnprintf (buffer, buffer_size, "dbi_conn_error failed with status %i",
+        status);
+
+  return (buffer);
+} /* }}} const char *cdbi_conn_error */
+
+static int cdbi_result_get_field (dbi_result res, /* {{{ */
+    const char *name, int dst_type, value_t *ret_value)
+{
+  value_t value;
+  unsigned int index;
+  unsigned short src_type;
+  dbi_conn connection;
+
+  index = dbi_result_get_field_idx (res, name);
+  if (index < 1)
+  {
+    ERROR ("dbi plugin: cdbi_result_get: No such column: %s.", name);
+    return (-1);
+  }
+
+  src_type = dbi_result_get_field_type_idx (res, index);
+  if (src_type == DBI_TYPE_ERROR)
+  {
+    ERROR ("dbi plugin: cdbi_result_get: "
+        "dbi_result_get_field_type_idx failed.");
+    return (-1);
+  }
+
+  if ((dst_type != DS_TYPE_COUNTER) && (dst_type != DS_TYPE_GAUGE))
+  {
+    ERROR ("dbi plugin: cdbi_result_get: Don't know how to handle "
+        "destination type %i.", dst_type);
+    return (-1);
+  }
+
+  if (src_type == DBI_TYPE_INTEGER)
+  {
+    if (dst_type == DS_TYPE_COUNTER)
+      value.counter = dbi_result_get_ulonglong_idx (res, index);
+    else
+      value.gauge = (gauge_t) dbi_result_get_longlong_idx (res, index);
+  }
+  else if (src_type == DBI_TYPE_DECIMAL)
+  {
+    value.gauge = dbi_result_get_double_idx (res, index);
+    if (dst_type == DS_TYPE_COUNTER)
+      value.counter = (counter_t) round (value.gauge);
+  }
+  else if (src_type == DBI_TYPE_STRING)
+  {
+    const char *string = dbi_result_get_string_idx (res, index);
+    char *endptr = NULL;
+
+    if (string == NULL)
+      value.gauge = NAN;
+    else if (dst_type == DS_TYPE_COUNTER)
+      value.counter = (counter_t) strtoll (string, &endptr, 0);
+    else
+      value.gauge = (gauge_t) strtod (string, &endptr);
+
+    if (string == endptr)
+    {
+      ERROR ("dbi plugin: cdbi_result_get: Can't parse string as number: %s.",
+          string);
+      return (-1);
+    }
+  }
+  else
+  {
+    ERROR ("dbi plugin: cdbi_result_get: Don't know how to handle "
+        "source type %hu.", src_type);
+    return (-1);
+  }
+
+  connection = dbi_result_get_conn (res);
+  if (dbi_conn_error_flag (connection) != 0)
+  {
+    char errbuf[1024];
+    ERROR ("dbi plugin: cdbi_result_get: dbi_result_get_*_idx failed: %s.",
+        cdbi_strerror (connection, errbuf, sizeof (errbuf)));
+    return (-1);
+  }
+
+  *ret_value = value;
+  return (0);
+} /* }}} int cdbi_result_get_field */
+
+static void cdbi_query_free (cdbi_query_t *q) /* {{{ */
+{
+  size_t i;
+
+  if (q == NULL)
+    return;
+
+  sfree (q->name);
+  sfree (q->statement);
+  sfree (q->type);
+
+  for (i = 0; i < q->instances_num; i++)
+    sfree (q->instances[i]);
+  sfree (q->instances);
+
+  for (i = 0; i < q->values_num; i++)
+    sfree (q->values[i]);
+  sfree (q->values);
+
+  sfree (q);
+} /* }}} void cdbi_query_free */
+
+static void cdbi_database_free (cdbi_database_t *db) /* {{{ */
+{
+  size_t i;
+
+  if (db == NULL)
+    return;
+
+  sfree (db->name);
+  sfree (db->driver);
+
+  for (i = 0; i < db->driver_options_num; i++)
+  {
+    sfree (db->driver_options[i].key);
+    sfree (db->driver_options[i].value);
+  }
+  sfree (db->driver_options);
+
+  sfree (db);
+} /* }}} void cdbi_database_free */
+
+static void cdbi_submit (cdbi_database_t *db, cdbi_query_t *q, /* {{{ */
+    char **instances, value_t *values)
+{
+  value_list_t vl = VALUE_LIST_INIT;
+
+  vl.values = values;
+  vl.values_len = (int) q->values_num;
+  vl.time = time (NULL);
+  sstrncpy (vl.host, hostname_g, sizeof (vl.host));
+  sstrncpy (vl.plugin, "dbi", sizeof (vl.plugin));
+  sstrncpy (vl.plugin_instance, db->name, sizeof (vl.type_instance));
+  sstrncpy (vl.type, q->type, sizeof (vl.type));
+  strjoin (vl.type_instance, sizeof (vl.type_instance),
+      instances, q->instances_num, "-");
+  vl.type_instance[sizeof (vl.type_instance) - 1] = 0;
+
+  plugin_dispatch_values (&vl);
+} /* }}} void cdbi_submit */
+
+/* Configuration handling functions {{{
+ *
+ * <Plugin dbi>
+ *   <Query "plugin_instance0">
+ *     Statement "SELECT name, value FROM table"
+ *     Type "gauge"
+ *     InstancesFrom "name"
+ *     ValuesFrom "value"
+ *   </Query>
+ *     
+ *   <Database "plugin_instance1">
+ *     Driver "mysql"
+ *     DriverOption "hostname" "localhost"
+ *     ...
+ *     Query "plugin_instance0"
+ *   </Database>
+ * </Plugin>
+ */
+
+static int cdbi_config_set_string (char **ret_string, /* {{{ */
+    oconfig_item_t *ci)
+{
+  char *string;
+
+  if ((ci->values_num != 1)
+      || (ci->values[0].type != OCONFIG_TYPE_STRING))
+  {
+    WARNING ("dbi plugin: The `%s' config option "
+        "needs exactly one string argument.", ci->key);
+    return (-1);
+  }
+
+  string = strdup (ci->values[0].value.string);
+  if (string == NULL)
+  {
+    ERROR ("dbi plugin: strdup failed.");
+    return (-1);
+  }
+
+  if (*ret_string != NULL)
+    free (*ret_string);
+  *ret_string = string;
+
+  return (0);
+} /* }}} int cdbi_config_set_string */
+
+static int cdbi_config_add_string (char ***ret_array, /* {{{ */
+    size_t *ret_array_len, oconfig_item_t *ci)
+{
+  char **array;
+  size_t array_len;
+  int i;
+
+  if (ci->values_num < 1)
+  {
+    WARNING ("dbi plugin: The `%s' config option "
+        "needs at least one argument.", ci->key);
+    return (-1);
+  }
+
+  for (i = 0; i < ci->values_num; i++)
+  {
+    if (ci->values[i].type != OCONFIG_TYPE_STRING)
+    {
+      WARNING ("dbi plugin: Argument %i to the `%s' option "
+          "is not a string.", i + 1, ci->key);
+      return (-1);
+    }
+  }
+
+  array_len = *ret_array_len;
+  array = (char **) realloc (*ret_array,
+      sizeof (char *) * (array_len + ci->values_num));
+  if (array == NULL)
+  {
+    ERROR ("dbi plugin: realloc failed.");
+    return (-1);
+  }
+  *ret_array = array;
+
+  for (i = 0; i < ci->values_num; i++)
+  {
+    array[array_len] = strdup (ci->values[i].value.string);
+    if (array[array_len] == NULL)
+    {
+      ERROR ("dbi plugin: strdup failed.");
+      *ret_array_len = array_len;
+      return (-1);
+    }
+    array_len++;
+  }
+
+  *ret_array_len = array_len;
+  return (0);
+} /* }}} int cdbi_config_add_string */
+
+static int cdbi_config_add_query (oconfig_item_t *ci) /* {{{ */
+{
+  cdbi_query_t *q;
+  int status;
+  int i;
+
+  if ((ci->values_num != 1)
+      || (ci->values[0].type != OCONFIG_TYPE_STRING))
+  {
+    WARNING ("dbi plugin: The `Query' block "
+        "needs exactly one string argument.");
+    return (-1);
+  }
+
+  q = (cdbi_query_t *) malloc (sizeof (*q));
+  if (q == NULL)
+  {
+    ERROR ("dbi plugin: malloc failed.");
+    return (-1);
+  }
+  memset (q, 0, sizeof (*q));
+
+  status = cdbi_config_set_string (&q->name, ci);
+  if (status != 0)
+  {
+    sfree (q);
+    return (status);
+  }
+
+  /* Fill the `cdbi_query_t' structure.. */
+  for (i = 0; i < ci->children_num; i++)
+  {
+    oconfig_item_t *child = ci->children + i;
+
+    if (strcasecmp ("Statement", child->key) == 0)
+      status = cdbi_config_set_string (&q->statement, child);
+    else if (strcasecmp ("Type", child->key) == 0)
+      status = cdbi_config_set_string (&q->type, child);
+    else if (strcasecmp ("InstancesFrom", child->key) == 0)
+      status = cdbi_config_add_string (&q->instances, &q->instances_num, child);
+    else if (strcasecmp ("ValuesFrom", child->key) == 0)
+      status = cdbi_config_add_string (&q->values, &q->values_num, child);
+    else
+    {
+      WARNING ("dbi plugin: Option `%s' not allowed here.", child->key);
+      status = -1;
+    }
+
+    if (status != 0)
+      break;
+  }
+
+  /* Check that all necessary options have been given. */
+  while (status == 0)
+  {
+    if (q->statement == NULL)
+    {
+      WARNING ("dbi plugin: `Statement' not given for query `%s'", q->name);
+      status = -1;
+    }
+    if (q->type == NULL)
+    {
+      WARNING ("dbi plugin: `Type' not given for query `%s'", q->name);
+      status = -1;
+    }
+    if (q->instances == NULL)
+    {
+      WARNING ("dbi plugin: `InstancesFrom' not given for query `%s'", q->name);
+      status = -1;
+    }
+    if (q->values == NULL)
+    {
+      WARNING ("dbi plugin: `ValuesFrom' not given for query `%s'", q->name);
+      status = -1;
+    }
+
+    break;
+  } /* while (status == 0) */
+
+  /* If all went well, add this query to the list of queries within the
+   * database structure. */
+  if (status == 0)
+  {
+    cdbi_query_t **temp;
+
+    temp = (cdbi_query_t **) realloc (queries,
+        sizeof (*queries) * (queries_num + 1));
+    if (temp == NULL)
+    {
+      ERROR ("dbi plugin: realloc failed");
+      status = -1;
+    }
+    else
+    {
+      queries = temp;
+      queries[queries_num] = q;
+      queries_num++;
+    }
+  }
+
+  if (status != 0)
+  {
+    cdbi_query_free (q);
+    return (-1);
+  }
+
+  return (0);
+} /* }}} int cdbi_config_add_query */
+
+static int cdbi_config_add_database_driver_option (cdbi_database_t *db, /* {{{ */
+    oconfig_item_t *ci)
+{
+  cdbi_driver_option_t *option;
+
+  if ((ci->values_num != 2)
+      || (ci->values[0].type != OCONFIG_TYPE_STRING)
+      || (ci->values[1].type != OCONFIG_TYPE_STRING))
+  {
+    WARNING ("dbi plugin: The `DriverOption' config option "
+        "needs exactly two string arguments.");
+    return (-1);
+  }
+
+  option = (cdbi_driver_option_t *) realloc (db->driver_options,
+      sizeof (*option) * (db->driver_options_num + 1));
+  if (option == NULL)
+  {
+    ERROR ("dbi plugin: realloc failed");
+    return (-1);
+  }
+
+  db->driver_options = option;
+  option = db->driver_options + db->driver_options_num;
+
+  option->key = strdup (ci->values[0].value.string);
+  if (option->key == NULL)
+  {
+    ERROR ("dbi plugin: strdup failed.");
+    return (-1);
+  }
+
+  option->value = strdup (ci->values[1].value.string);
+  if (option->value == NULL)
+  {
+    ERROR ("dbi plugin: strdup failed.");
+    sfree (option->key);
+    return (-1);
+  }
+
+  db->driver_options_num++;
+  return (0);
+} /* }}} int cdbi_config_add_database_driver_option */
+
+static int cdbi_config_add_database_query (cdbi_database_t *db, /* {{{ */
+    oconfig_item_t *ci)
+{
+  cdbi_query_t *q;
+  cdbi_query_t **temp;
+  size_t i;
+
+  if ((ci->values_num != 1)
+      || (ci->values[0].type != OCONFIG_TYPE_STRING))
+  {
+    WARNING ("dbi plugin: The `Query' config option "
+        "needs exactly one string argument.");
+    return (-1);
+  }
+
+  q = NULL;
+  for (i = 0; i < queries_num; i++)
+  {
+    if (strcasecmp (queries[i]->name, ci->values[0].value.string) == 0)
+    {
+      q = queries[i];
+      break;
+    }
+  }
+
+  if (q == NULL)
+  {
+    WARNING ("dbi plugin: Database `%s': Unknown query `%s'. "
+        "Please make sure that the <Query \"%s\"> block comes before "
+        "the <Database \"%s\"> block.",
+        db->name, ci->values[0].value.string,
+        ci->values[0].value.string, db->name);
+    return (-1);
+  }
+
+  temp = (cdbi_query_t **) realloc (db->queries,
+      sizeof (*db->queries) * (db->queries_num + 1));
+  if (temp == NULL)
+  {
+    ERROR ("dbi plugin: realloc failed");
+    return (-1);
+  }
+  else
+  {
+    db->queries = temp;
+    db->queries[db->queries_num] = q;
+    db->queries_num++;
+  }
+
+  return (0);
+} /* }}} int cdbi_config_add_database_query */
+
+static int cdbi_config_add_database (oconfig_item_t *ci) /* {{{ */
+{
+  cdbi_database_t *db;
+  int status;
+  int i;
+
+  if ((ci->values_num != 1)
+      || (ci->values[0].type != OCONFIG_TYPE_STRING))
+  {
+    WARNING ("dbi plugin: The `Database' block "
+        "needs exactly one string argument.");
+    return (-1);
+  }
+
+  db = (cdbi_database_t *) malloc (sizeof (*db));
+  if (db == NULL)
+  {
+    ERROR ("dbi plugin: malloc failed.");
+    return (-1);
+  }
+  memset (db, 0, sizeof (*db));
+
+  status = cdbi_config_set_string (&db->name, ci);
+  if (status != 0)
+  {
+    sfree (db);
+    return (status);
+  }
+
+  /* Fill the `cdbi_database_t' structure.. */
+  for (i = 0; i < ci->children_num; i++)
+  {
+    oconfig_item_t *child = ci->children + i;
+
+    if (strcasecmp ("Driver", child->key) == 0)
+      status = cdbi_config_set_string (&db->driver, child);
+    else if (strcasecmp ("DriverOption", child->key) == 0)
+      status = cdbi_config_add_database_driver_option (db, child);
+    else if (strcasecmp ("SelectDB", child->key) == 0)
+      status = cdbi_config_set_string (&db->select_db, child);
+    else if (strcasecmp ("Query", child->key) == 0)
+      status = cdbi_config_add_database_query (db, child);
+    else
+    {
+      WARNING ("dbi plugin: Option `%s' not allowed here.", child->key);
+      status = -1;
+    }
+
+    if (status != 0)
+      break;
+  }
+
+  /* Check that all necessary options have been given. */
+  while (status == 0)
+  {
+    if (db->driver == NULL)
+    {
+      WARNING ("dbi plugin: `Driver' not given for database `%s'", db->name);
+      status = -1;
+    }
+    if (db->driver_options_num == 0)
+    {
+      WARNING ("dbi plugin: No `DriverOption' given for database `%s'. "
+          "This will likely not work.", db->name);
+    }
+
+    break;
+  } /* while (status == 0) */
+
+  /* If all went well, add this database to the global list of databases. */
+  if (status == 0)
+  {
+    cdbi_database_t **temp;
+
+    temp = (cdbi_database_t **) realloc (databases,
+        sizeof (*databases) * (databases_num + 1));
+    if (temp == NULL)
+    {
+      ERROR ("dbi plugin: realloc failed");
+      status = -1;
+    }
+    else
+    {
+      databases = temp;
+      databases[databases_num] = db;
+      databases_num++;
+    }
+  }
+
+  if (status != 0)
+  {
+    cdbi_database_free (db);
+    return (-1);
+  }
+
+  return (0);
+} /* }}} int cdbi_config_add_database */
+
+static int cdbi_config (oconfig_item_t *ci) /* {{{ */
+{
+  int i;
+
+  for (i = 0; i < ci->children_num; i++)
+  {
+    oconfig_item_t *child = ci->children + i;
+    if (strcasecmp ("Query", child->key) == 0)
+      cdbi_config_add_query (child);
+    else if (strcasecmp ("Database", child->key) == 0)
+      cdbi_config_add_database (child);
+    else
+    {
+      WARNING ("snmp plugin: Ignoring unknown config option `%s'.", child->key);
+    }
+  } /* for (ci->children) */
+
+  return (0);
+} /* }}} int cdbi_config */
+
+/* }}} End of configuration handling functions */
+
+static int cdbi_init (void) /* {{{ */
+{
+  static int did_init = 0;
+  int status;
+
+  if (did_init != 0)
+    return (0);
+
+  if (queries_num == 0)
+  {
+    ERROR ("dbi plugin: No <Query> blocks have been found. Without them, "
+        "this plugin can't do anything useful, so we will returns an error.");
+    return (-1);
+  }
+
+  if (databases_num == 0)
+  {
+    ERROR ("dbi plugin: No <Database> blocks have been found. Without them, "
+        "this plugin can't do anything useful, so we will returns an error.");
+    return (-1);
+  }
+
+  status = dbi_initialize (NULL);
+  if (status < 0)
+  {
+    ERROR ("dbi plugin: cdbi_init: dbi_initialize failed with status %i.",
+        status);
+    return (-1);
+  }
+  else if (status == 0)
+  {
+    ERROR ("dbi plugin: `dbi_initialize' could not load any drivers. Please "
+        "install at least one `DBD' or check your installation.");
+    return (-1);
+  }
+  DEBUG ("dbi plugin: cdbi_init: dbi_initialize reports %i driver%s.",
+      status, (status == 1) ? "" : "s");
+
+  return (0);
+} /* }}} int cdbi_init */
+
+static int cdbi_read_database_query (cdbi_database_t *db, /* {{{ */
+    cdbi_query_t *q)
+{
+  dbi_result res;
+  char **instances;
+  value_t *values;
+  const data_set_t *ds;
+  size_t i;
+  int status;
+
+  res = NULL;
+  instances = NULL;
+  values = NULL;
+
+  /* Macro that cleans up dynamically allocated memory and returns the
+   * specified status. */
+#define BAIL_OUT(status) \
+  if (res != NULL) { dbi_result_free (res); res = NULL; } \
+  if (instances != NULL) { sfree (instances[0]); sfree (instances); } \
+  sfree (values); \
+  return (status)
+
+  ds = plugin_get_ds (q->type);
+  if (ds == NULL)
+  {
+    ERROR ("dbi plugin: cdbi_read_database_query: Query `%s': Type `%s' is not "
+        "known by the daemon. See types.db(5) for details.",
+        q->name, q->type);
+    BAIL_OUT (-1);
+  }
+
+  if (((size_t) ds->ds_num) != q->values_num)
+  {
+    ERROR ("dbi plugin: cdbi_read_database_query: Query `%s': The type `%s' "
+        "requires exactly %i value%s, but the configuration specifies %zu.",
+        q->name, q->type,
+        ds->ds_num, (ds->ds_num == 1) ? "" : "s",
+        q->values_num);
+    BAIL_OUT (-1);
+  }
+
+  /* Allocate `instances' and `values' {{{ */
+  instances = (char **) malloc (sizeof (*instances) * q->instances_num);
+  if (instances == NULL)
+  {
+    ERROR ("dbi plugin: malloc failed.");
+    BAIL_OUT (-1);
+  }
+
+  instances[0] = (char *) malloc (q->instances_num * DATA_MAX_NAME_LEN);
+  if (instances[0] == NULL)
+  {
+    ERROR ("dbi plugin: malloc failed.");
+    BAIL_OUT (-1);
+  }
+  for (i = 1; i < q->instances_num; i++)
+    instances[i] = instances[i - 1] + DATA_MAX_NAME_LEN;
+
+  values = (value_t *) malloc (sizeof (*values) * q->values_num);
+  if (values == NULL)
+  {
+    ERROR ("dbi plugin: malloc failed.");
+    BAIL_OUT (-1);
+  }
+  /* }}} */
+
+  res = dbi_conn_query (db->connection, q->statement);
+  if (res == NULL)
+  {
+    char errbuf[1024];
+    ERROR ("dbi plugin: cdbi_read_database_query (%s, %s): "
+        "dbi_conn_query failed: %s",
+        db->name, q->name,
+        cdbi_strerror (db->connection, errbuf, sizeof (errbuf)));
+    BAIL_OUT (-1);
+  }
+
+  status = dbi_result_first_row (res);
+  if (status != 1)
+  {
+    char errbuf[1024];
+    ERROR ("dbi plugin: cdbi_read_database_query (%s, %s): "
+        "dbi_result_first_row failed: %s. Maybe the statement didn't "
+        "return any rows?",
+        db->name, q->name, 
+        cdbi_strerror (db->connection, errbuf, sizeof (errbuf)));
+    BAIL_OUT (-1);
+  }
+
+  while (42)
+  {
+    /* Get instance names and values from the result: */
+    for (i = 0; i < q->instances_num; i++) /* {{{ */
+    {
+      const char *inst;
+
+      inst = dbi_result_get_string (res, q->instances[i]);
+      if (dbi_conn_error_flag (db->connection) != 0)
+      {
+        char errbuf[1024];
+        ERROR ("dbi plugin: cdbi_read_database_query (%s, %s): "
+            "dbi_result_get_string (%s) failed: %s",
+            db->name, q->name, q->instances[i],
+            cdbi_strerror (db->connection, errbuf, sizeof (errbuf)));
+        BAIL_OUT (-1);
+      }
+
+      sstrncpy (instances[i], (inst == NULL) ? "" : inst, DATA_MAX_NAME_LEN);
+      DEBUG ("dbi plugin: cdbi_read_database_query (%s, %s): "
+          "instances[%zu] = %s;",
+          db->name, q->name, i, instances[i]);
+    } /* }}} for (i = 0; i < q->instances_num; i++) */
+
+    for (i = 0; i < q->values_num; i++) /* {{{ */
+    {
+      status = cdbi_result_get_field (res, q->values[i], ds->ds[i].type,
+          values + i);
+      if (status != 0)
+      {
+        BAIL_OUT (-1);
+      }
+
+      if (ds->ds[i].type == DS_TYPE_COUNTER)
+      {
+        DEBUG ("dbi plugin: cdbi_read_database_query (%s, %s): values[%zu] = %llu;",
+            db->name, q->name, i, values[i].counter);
+      }
+      else
+      {
+        DEBUG ("dbi plugin: cdbi_read_database_query (%s, %s): values[%zu] = %g;",
+            db->name, q->name, i, values[i].gauge);
+      }
+    } /* }}} for (i = 0; i < q->values_num; i++) */
+
+    /* Dispatch this row to the daemon. */
+    cdbi_submit (db, q, instances, values);
+
+    /* Get the next row from the database. */
+    status = dbi_result_next_row (res);
+    if (status != 1)
+    {
+      if (dbi_conn_error_flag (db->connection) != 0)
+      {
+        char errbuf[1024];
+        WARNING ("dbi plugin: cdbi_read_database_query (%s, %s): "
+            "dbi_result_next_row failed: %s.",
+            db->name, q->name,
+            cdbi_strerror (db->connection, errbuf, sizeof (errbuf)));
+      }
+      break;
+    }
+  } /* while (42) */
+
+  BAIL_OUT (0);
+#undef BAIL_OUT
+} /* }}} int cdbi_read_database_query */
+
+static int cdbi_connect_database (cdbi_database_t *db) /* {{{ */
+{
+  dbi_driver driver;
+  dbi_conn connection;
+  size_t i;
+  int status;
+
+  if (db->connection != NULL)
+  {
+    status = dbi_conn_ping (db->connection);
+    if (status != 0) /* connection is alive */
+      return (0);
+
+    dbi_conn_close (db->connection);
+    db->connection = NULL;
+  }
+
+  driver = dbi_driver_open (db->driver);
+  if (driver == NULL)
+  {
+    ERROR ("dbi plugin: cdbi_connect_database: dbi_driver_open (%s) failed.",
+        db->driver);
+    INFO ("dbi plugin: Maybe the driver isn't installed? "
+        "Known drivers are:");
+    for (driver = dbi_driver_list (NULL);
+        driver != NULL;
+        driver = dbi_driver_list (driver))
+    {
+      INFO ("dbi plugin: * %s", dbi_driver_get_name (driver));
+    }
+    return (-1);
+  }
+
+  connection = dbi_conn_open (driver);
+  if (connection == NULL)
+  {
+    ERROR ("dbi plugin: cdbi_connect_database: dbi_conn_open (%s) failed.",
+        db->driver);
+    return (-1);
+  }
+
+  /* Set all the driver options. Because this is a very very very generic
+   * interface, the error handling is kind of long. If an invalid option is
+   * encountered, it will get a list of options understood by the driver and
+   * report that as `INFO'. This way, users hopefully don't have too much
+   * trouble finding out how to configure the plugin correctly.. */
+  for (i = 0; i < db->driver_options_num; i++)
+  {
+    DEBUG ("dbi plugin: cdbi_connect_database (%s): "
+        "key = %s; value = %s;",
+        db->name,
+        db->driver_options[i].key,
+        db->driver_options[i].value);
+
+    status = dbi_conn_set_option (connection,
+        db->driver_options[i].key, db->driver_options[i].value);
+    if (status != 0)
+    {
+      char errbuf[1024];
+      const char *opt;
+
+      ERROR ("dbi plugin: cdbi_connect_database (%s): "
+          "dbi_conn_set_option (%s, %s) failed: %s.",
+          db->name,
+          db->driver_options[i].key, db->driver_options[i].value,
+          cdbi_strerror (connection, errbuf, sizeof (errbuf)));
+
+      INFO ("dbi plugin: This is a list of all options understood "
+          "by the `%s' driver:", db->driver);
+      for (opt = dbi_conn_get_option_list (connection, NULL);
+          opt != NULL;
+          opt = dbi_conn_get_option_list (connection, opt))
+      {
+        INFO ("dbi plugin: * %s", opt);
+      }
+
+      dbi_conn_close (connection);
+      return (-1);
+    }
+  } /* for (i = 0; i < db->driver_options_num; i++) */
+
+  status = dbi_conn_connect (connection);
+  if (status != 0)
+  {
+    char errbuf[1024];
+    ERROR ("dbi plugin: cdbi_connect_database (%s): "
+        "dbi_conn_connect failed: %s",
+        db->name, cdbi_strerror (connection, errbuf, sizeof (errbuf)));
+    dbi_conn_close (connection);
+    return (-1);
+  }
+
+  if (db->select_db != NULL)
+  {
+    status = dbi_conn_select_db (connection, db->select_db);
+    if (status != 0)
+    {
+      char errbuf[1024];
+      WARNING ("dbi plugin: cdbi_connect_database (%s): "
+          "dbi_conn_select_db (%s) failed: %s. Check the `SelectDB' option.",
+          db->name, db->select_db,
+          cdbi_strerror (connection, errbuf, sizeof (errbuf)));
+      dbi_conn_close (connection);
+      return (-1);
+    }
+  }
+
+  db->connection = connection;
+  return (0);
+} /* }}} int cdbi_connect_database */
+
+static int cdbi_read_database (cdbi_database_t *db) /* {{{ */
+{
+  size_t i;
+  int success;
+  int status;
+
+  status = cdbi_connect_database (db);
+  if (status != 0)
+    return (status);
+  assert (db->connection != NULL);
+
+  success = 0;
+  for (i = 0; i < db->queries_num; i++)
+  {
+    status = cdbi_read_database_query (db, db->queries[i]);
+    if (status == 0)
+      success++;
+  }
+
+  if (success == 0)
+  {
+    ERROR ("dbi plugin: All queries failed for database `%s'.", db->name);
+    return (-1);
+  }
+
+  return (0);
+} /* }}} int cdbi_read_database */
+
+static int cdbi_read (void) /* {{{ */
+{
+  size_t i;
+  int success = 0;
+  int status;
+
+  for (i = 0; i < databases_num; i++)
+  {
+    status = cdbi_read_database (databases[i]);
+    if (status == 0)
+      success++;
+  }
+
+  if (success == 0)
+  {
+    ERROR ("dbi plugin: No database could be read. Will return an error so "
+        "the plugin will be delayed.");
+    return (-1);
+  }
+
+  return (0);
+} /* }}} int cdbi_read */
+
+static int cdbi_shutdown (void) /* {{{ */
+{
+  size_t i;
+
+  for (i = 0; i < databases_num; i++)
+  {
+    if (databases[i]->connection != NULL)
+    {
+      dbi_conn_close (databases[i]->connection);
+      databases[i]->connection = NULL;
+    }
+    cdbi_database_free (databases[i]);
+  }
+  sfree (databases);
+  databases_num = 0;
+
+  for (i = 0; i < queries_num; i++)
+    cdbi_query_free (queries[i]);
+  sfree (queries);
+  queries_num = 0;
+
+  return (0);
+} /* }}} int cdbi_shutdown */
+
+void module_register (void) /* {{{ */
+{
+  plugin_register_complex_config ("dbi", cdbi_config);
+  plugin_register_init ("dbi", cdbi_init);
+  plugin_register_read ("dbi", cdbi_read);
+  plugin_register_shutdown ("dbi", cdbi_shutdown);
+} /* }}} void module_register */
+
+/*
+ * vim: shiftwidth=2 softtabstop=2 et fdm=marker
+ */