MDEV-15 Log all SQL errors.

              Added the logger service that provides us with the rotating logs.
              The plugin SQL_ERROR_LOG added. It logs the errors using the 'logger service'
                      for the rotating log files.
              the example record from the log:
                2012-03-09 15:07:29 root[root] @ localhost [] ERROR 1146: Table 'test.xyz' doesn't exist : select * from test.xyz

2 files changed, 163 insertions, 0 deletions

diff --git a/plugin/sql_errlog/CMakeLists.txt b/plugin/sql_errlog/CMakeLists.txt
new file mode 100644
index 00000000000..18fb9f5421d
--- /dev/null
+++ b/plugin/sql_errlog/CMakeLists.txt
@@ -0,0 +1,16 @@
+# Copyright (C) 2012 Monty Program Ab.
+# 
+# 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; version 2 of the License.
+# 
+# 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
+
+MYSQL_ADD_PLUGIN(sql_errlog sql_errlog.c MODULE_ONLY)
diff --git a/plugin/sql_errlog/sql_errlog.c b/plugin/sql_errlog/sql_errlog.c
new file mode 100644
index 00000000000..53d804feeb3
--- /dev/null
+++ b/plugin/sql_errlog/sql_errlog.c
@@ -0,0 +1,147 @@
+/* Copyright (C) 2012 Monty Program Ab.
+
+   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; version 2 of the License.
+
+   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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */
+
+#include <mysql/plugin_audit.h>
+#include <stdio.h>
+#include <time.h>
+
+/*
+  rate 0 means the logging was disabled.
+*/
+
+static char *filename;
+static unsigned int rate;
+static unsigned int size_limit;
+static unsigned int rotations;
+static char rotate;
+
+static unsigned int count;
+LOGGER_HANDLE *logfile;
+
+static void rotate_log(MYSQL_THD thd, struct st_mysql_sys_var *var,
+                       void *var_ptr, const void *save);
+
+static MYSQL_SYSVAR_UINT(rate, rate, PLUGIN_VAR_RQCMDARG,
+       "Sampling rate. If set to 0(zero), the logging is disabled.", NULL, NULL,
+       1, 0, 1000000, 1);
+
+static MYSQL_SYSVAR_UINT(size_limit, size_limit,
+       PLUGIN_VAR_READONLY, "Log file size limit", NULL, NULL,
+       1000000, 100, 1024*1024L*1024L, 1);
+
+static MYSQL_SYSVAR_UINT(rotations, rotations,
+       PLUGIN_VAR_READONLY, "Number of rotations before log is removed.",
+       NULL, NULL, 9, 1, 999, 1);
+
+static MYSQL_SYSVAR_BOOL(rotate, rotate,
+       PLUGIN_VAR_OPCMDARG, "Force log rotation", NULL, rotate_log,
+       0);
+
+static MYSQL_SYSVAR_STR(filename, filename,
+       PLUGIN_VAR_READONLY | PLUGIN_VAR_RQCMDARG,
+       "The file to log sql errors to", NULL, NULL,
+       "sql_errors.log");
+
+static struct st_mysql_sys_var* vars[] = {
+    MYSQL_SYSVAR(rate),
+    MYSQL_SYSVAR(size_limit),
+    MYSQL_SYSVAR(rotations),
+    MYSQL_SYSVAR(rotate),
+    MYSQL_SYSVAR(filename),
+    NULL
+};
+
+
+static void log_sql_errors(MYSQL_THD thd __attribute__((unused)),
+                           unsigned int event_class __attribute__((unused)),
+                           const void *ev)
+{
+  const struct mysql_event_general *event =
+         (const struct mysql_event_general*)ev;
+  if (rate &&
+      event->event_subclass == MYSQL_AUDIT_GENERAL_ERROR)
+  {
+    if (++count >= rate)
+    {
+      struct tm t;
+      time_t event_time = event->general_time;
+
+      count = 0;
+      localtime_r(&event_time, &t);
+      logger_printf(logfile, "%04d-%02d-%02d %2d:%02d:%02d "
+                      "%s ERROR %d: %s : %s\n",
+              t.tm_year + 1900, t.tm_mon + 1,
+              t.tm_mday, t.tm_hour, t.tm_min, t.tm_sec,
+              event->general_user, event->general_error_code,
+              event->general_command, event->general_query);
+    }
+  }
+}
+
+
+static int sql_error_log_init(void *p __attribute__((unused)))
+{
+  logfile= logger_open(filename, size_limit, rotations);
+  if (logfile == NULL) {
+    fprintf(stderr, "Could not create file '%s'\n",
+            filename);
+    return 1;
+  }
+  count = 0;
+  return 0;
+}
+
+
+static int sql_error_log_deinit(void *p __attribute__((unused)))
+{
+  logger_close(logfile);
+  return 0;
+}
+
+
+static void rotate_log(MYSQL_THD thd  __attribute__((unused)),
+                       struct st_mysql_sys_var *var  __attribute__((unused)),
+                       void *var_ptr  __attribute__((unused)),
+                       const void *save  __attribute__((unused)))
+{
+  (void) logger_rotate(logfile);
+}
+
+
+static struct st_mysql_audit descriptor =
+{
+  MYSQL_AUDIT_INTERFACE_VERSION,
+  NULL,
+  log_sql_errors,
+  { MYSQL_AUDIT_GENERAL_CLASSMASK }
+};
+
+maria_declare_plugin(sql_errlog)
+{
+  MYSQL_AUDIT_PLUGIN,
+  &descriptor,
+  "SQL_ERROR_LOG",
+  "Alexey Botchkov",
+  "Log SQL level errors to a file with rotation",
+  PLUGIN_LICENSE_GPL,
+  sql_error_log_init,
+  sql_error_log_deinit,
+  0x0100,
+  NULL,
+  vars,
+  "1.0",
+  MariaDB_PLUGIN_MATURITY_ALPHA
+}
+maria_declare_plugin_end;