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, 169 insertions, 1 deletions

diff --git a/mysys/CMakeLists.txt b/mysys/CMakeLists.txt
index 7397990eddb..5204f7e873c 100644
--- a/mysys/CMakeLists.txt
+++ b/mysys/CMakeLists.txt
@@ -37,7 +37,7 @@ SET(MYSYS_SOURCES  array.c charset-def.c charset.c checksum.c default.c
                 safemalloc.c my_new.cc
 				my_atomic.c my_getncpus.c my_safehash.c my_chmod.c my_rnd.c
                                 my_uuid.c wqueue.c waiting_threads.c ma_dyncol.c
-				my_rdtsc.c my_context.c)
+				my_rdtsc.c my_context.c my_logger.c)
 
 IF (WIN32)
  SET (MYSYS_SOURCES ${MYSYS_SOURCES} my_winthread.c my_wincond.c my_winerr.c my_winfile.c my_windac.c my_conio.c)
diff --git a/mysys/my_logger.c b/mysys/my_logger.c
new file mode 100644
index 00000000000..292c98f4ad1
--- /dev/null
+++ b/mysys/my_logger.c
@@ -0,0 +1,168 @@
+/* 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 "my_global.h"
+#include <my_sys.h>
+#include <mysql/service_logger.h>
+
+extern char *mysql_data_home;
+extern PSI_mutex_key key_LOCK_logger_service;
+
+typedef struct logger_handle_st {
+  FILE *file;
+  char path[FN_REFLEN];
+  long size_limit;
+  unsigned int rotations;
+  size_t path_len;
+  mysql_mutex_t lock;
+} LSFS;
+
+
+static unsigned int n_dig(unsigned int i)
+{
+  return (i == 0) ? 0 : ((i < 10) ? 1 : ((i < 100) ? 2 : 3));
+}
+
+
+LOGGER_HANDLE *logger_open(const char *path,
+                           unsigned long size_limit,
+                           unsigned int rotations)
+{
+  LOGGER_HANDLE new_log, *l_perm;
+
+  /*
+    I don't think we ever need more rotations,
+    but if it's so, the rotation procedure should be adapted to it.
+  */
+  if (rotations > 999)
+    return 0;
+
+  new_log.rotations= rotations;
+  new_log.size_limit= size_limit;
+  new_log.path_len= strlen(fn_format(new_log.path, path,
+        mysql_data_home, "", MY_UNPACK_FILENAME));
+
+  if (new_log.path_len+n_dig(rotations)+1 > FN_REFLEN)
+  {
+    errno= ENAMETOOLONG;
+    /* File path too long */
+    return 0;
+  }
+  if (!(new_log.file= fopen(new_log.path, "a+")))
+  {
+    /* Check errno for the cause */
+    return 0;
+  }
+
+  setbuf(new_log.file, 0);
+  fseek(new_log.file, 0, SEEK_END);
+  if (!(l_perm= (LOGGER_HANDLE *)
+          my_malloc(sizeof(LOGGER_HANDLE), MYF(0))))
+  {
+    fclose(new_log.file);
+    new_log.file= NULL;
+    return 0; /* End of memory */
+  }
+  *l_perm= new_log;
+  mysql_mutex_init(key_LOCK_logger_service, &l_perm->lock, MY_MUTEX_INIT_FAST);
+  return l_perm;
+}
+
+int logger_close(LOGGER_HANDLE *log)
+{
+  int result;
+  mysql_mutex_destroy(&log->lock);
+  result= fclose(log->file);
+  my_free(log);
+  return result;
+}
+
+
+static char *logname(LOGGER_HANDLE *log, char *buf, unsigned int n_log)
+{
+  sprintf(buf+log->path_len, ".%0*u", n_dig(log->rotations), n_log);
+  return buf;
+}
+
+
+static int do_rotate(LOGGER_HANDLE *log)
+{
+  char namebuf[FN_REFLEN];
+  int result;
+  unsigned int i;
+  char *buf_old, *buf_new, *tmp;
+
+  memcpy(namebuf, log->path, log->path_len);
+
+  buf_new= logname(log, namebuf, log->rotations);
+  buf_old= log->path;
+  for (i=log->rotations-1; i>0; i--)
+  {
+    logname(log, buf_old, i);
+    if (!access(buf_old, F_OK) &&
+        (result= my_rename(buf_old, buf_new, MYF(0))))
+      return result;
+    tmp= buf_old;
+    buf_old= buf_new;
+    buf_new= tmp;
+  }
+  if ((result= fclose(log->file)))
+    return result;
+  namebuf[log->path_len]= 0;
+  result= my_rename(namebuf, logname(log, log->path, 1), MYF(0));
+  log->file= fopen(namebuf, "a+");
+  return log->file==NULL || result;
+}
+
+
+int logger_vprintf(LOGGER_HANDLE *log, const char* fmt, va_list ap)
+{
+  int result;
+  mysql_mutex_lock(&log->lock);
+  if (ftell(log->file) >= log->size_limit &&
+      do_rotate(log))
+  {
+    result= -1;
+    goto exit; /* Log rotation needed but failed */
+  }
+
+  result= my_vfprintf(log->file, fmt, ap);
+exit:
+  mysql_mutex_unlock(&log->lock);
+  return result;
+}
+
+
+int logger_rotate(LOGGER_HANDLE *log)
+{
+  int result;
+  mysql_mutex_lock(&log->lock);
+  result= do_rotate(log);
+  mysql_mutex_unlock(&log->lock);
+  return result;
+}
+
+
+int logger_printf(LOGGER_HANDLE *log, const char *fmt, ...)
+{
+  int result;
+  va_list args;
+  va_start(args,fmt);
+  result= logger_vprintf(log, fmt, args);
+  va_end(args);
+  return result;
+}
+