Bug#21557 entries in the general query log truncated at 1000 characters.

The general log write function (general_log_print) uses printf style
arguments which need to be pre-processed, meaning that the all arguments
are copied to a single buffer and the problem is that the buffer size is
constant (1022 characters) but queries can be much larger then this.

The solution is to introduce a new log write function that accepts a
buffer and it's length as arguments. The function is to be used when
a formatted output is not required, which is the case for almost all
query write-to-log calls.

This is a incompatible change with respect to the log format of prepared
statements.


mysql-test/r/log_tables.result:
  Add test case result for Bug#21557
mysql-test/t/log_tables.test:
  Add test case for Bug#21557
sql/log.cc:
  Introduce the logger function general_log_write which is similar to
  general_log_print but accepts a single buffer and the buffer length.
  The function doesn't perform any formatting and sends the buffer
  directly to the underlying log handlers.
sql/log.h:
  Introduce the logger function general_log_write.
sql/log_event.cc:
  Pass the query buffer directly to the logger function, formatting
  is not required on this case.
sql/mysql_priv.h:
  Prototype for the logger function general_log_write.
sql/sp_head.cc:
  Pass the query buffer directly to the logger function, formatting
  is not required on this case.
sql/sql_parse.cc:
  Pass the buffer directly to the logger function when formatting
  is not required.
sql/sql_prepare.cc:
  Don't log the statement id, it avoids making a extra copy of the query
  and the query is not truncated anymore if it exceeds the limit.

7 files changed, 108 insertions, 77 deletions

diff --git a/sql/log.cc b/sql/log.cc
index 9d6f6fa4c9b..e923418b23a 100644
--- a/sql/log.cc
+++ b/sql/log.cc
@@ -944,73 +944,65 @@ bool LOGGER::slow_log_print(THD *thd, const char *query, uint query_length,
   return error;
 }
 
-bool LOGGER::general_log_print(THD *thd, enum enum_server_command command,
-                               const char *format, va_list args)
+bool LOGGER::general_log_write(THD *thd, enum enum_server_command command,
+                               const char *query, uint query_length)
 {
   bool error= FALSE;
   Log_event_handler **current_handler= general_log_handler_list;
+  char user_host_buff[MAX_USER_HOST_SIZE];
+  Security_context *sctx= thd->security_ctx;
+  ulong id;
+  uint user_host_len= 0;
+  time_t current_time;
 
-  /*
-    Print the message to the buffer if we have at least one log event handler
-    enabled and want to log this king of commands
-  */
-  if (*general_log_handler_list && (what_to_log & (1L << (uint) command)))
-  {
-    char message_buff[MAX_LOG_BUFFER_SIZE];
-    char user_host_buff[MAX_USER_HOST_SIZE];
-    Security_context *sctx= thd->security_ctx;
-    ulong id;
-    uint message_buff_len= 0, user_host_len= 0;
-    time_t current_time;
-    if (thd)
-    {                                           /* Normal thread */
-      if ((thd->options & OPTION_LOG_OFF)
-#ifndef NO_EMBEDDED_ACCESS_CHECKS
-          && (sctx->master_access & SUPER_ACL)
-#endif
-         )
-      {
-        return 0;                         /* No logging */
-      }
-      id= thd->thread_id;
-    }
-    else
-      id=0;                                     /* Log from connect handler */
+  if (thd)
+    id= thd->thread_id;                 /* Normal thread */
+  else
+    id= 0;                              /* Log from connect handler */
 
-    lock_shared();
-    if (!opt_log)
-    {
-      unlock();
-      return 0;
-    }
-    user_host_len= strxnmov(user_host_buff, MAX_USER_HOST_SIZE,
-                            sctx->priv_user ? sctx->priv_user : "", "[",
-                            sctx->user ? sctx->user : "", "] @ ",
-                            sctx->host ? sctx->host : "", " [",
-                            sctx->ip ? sctx->ip : "", "]", NullS) -
-                                                            user_host_buff;
-
-    /* prepare message */
-    if (format)
-      message_buff_len= my_vsnprintf(message_buff,
-                   sizeof(message_buff), format, args);
-    else
-      message_buff[0]= '\0';
-
-    current_time= my_time(0);
-    while (*current_handler)
-      error+= (*current_handler++)->
-        log_general(thd, current_time, user_host_buff,
-                   user_host_len, id,
-                   command_name[(uint) command].str,
-                   command_name[(uint) command].length,
-                   message_buff, message_buff_len,
-                   thd->variables.character_set_client) || error;
+  lock_shared();
+  if (!opt_log)
+  {
     unlock();
+    return 0;
   }
+  user_host_len= strxnmov(user_host_buff, MAX_USER_HOST_SIZE,
+                          sctx->priv_user ? sctx->priv_user : "", "[",
+                          sctx->user ? sctx->user : "", "] @ ",
+                          sctx->host ? sctx->host : "", " [",
+                          sctx->ip ? sctx->ip : "", "]", NullS) -
+                                                          user_host_buff;
+
+  current_time= my_time(0);
+  while (*current_handler)
+    error+= (*current_handler++)->
+      log_general(thd, current_time, user_host_buff,
+                  user_host_len, id,
+                  command_name[(uint) command].str,
+                  command_name[(uint) command].length,
+                  query, query_length,
+                  thd->variables.character_set_client) || error;
+  unlock();
+
   return error;
 }
 
+bool LOGGER::general_log_print(THD *thd, enum enum_server_command command,
+                               const char *format, va_list args)
+{
+  uint message_buff_len= 0;
+  char message_buff[MAX_LOG_BUFFER_SIZE];
+
+  /* prepare message */
+  if (format)
+    message_buff_len= my_vsnprintf(message_buff, sizeof(message_buff),
+                                   format, args);
+  else
+    message_buff[0]= '\0';
+
+  return general_log_write(thd, command, message_buff, message_buff_len);
+}
+
 void LOGGER::init_error_log(uint error_log_printer)
 {
   if (error_log_printer & LOG_NONE)
@@ -2075,10 +2067,10 @@ bool MYSQL_QUERY_LOG::write(THD *thd, time_t current_time,
         if (my_b_write(&log_file, (uchar*) buff, buff_len))
           tmp_errno= errno;
       }
-      if (my_b_printf(&log_file, "# User@Host: ", sizeof("# User@Host: ") - 1)
-          != sizeof("# User@Host: ") - 1)
+      const uchar uh[]= "# User@Host: ";
+      if (my_b_write(&log_file, uh, sizeof(uh) - 1))
         tmp_errno= errno;
-      if (my_b_printf(&log_file, user_host, user_host_len) != user_host_len)
+      if (my_b_write(&log_file, (uchar*) user_host, user_host_len))
         tmp_errno= errno;
       if (my_b_write(&log_file, (uchar*) "\n", 1))
         tmp_errno= errno;
@@ -3736,12 +3728,44 @@ bool slow_log_print(THD *thd, const char *query, uint query_length,
 }
 
 
+bool LOGGER::log_command(THD *thd, enum enum_server_command command)
+{
+#ifndef NO_EMBEDDED_ACCESS_CHECKS
+  Security_context *sctx= thd->security_ctx;
+#endif
+  /*
+    Log command if we have at least one log event handler enabled and want
+    to log this king of commands
+  */
+  if (*general_log_handler_list && (what_to_log & (1L << (uint) command)))
+  {
+    if ((thd->options & OPTION_LOG_OFF)
+#ifndef NO_EMBEDDED_ACCESS_CHECKS
+         && (sctx->master_access & SUPER_ACL)
+#endif
+       )
+    {
+      /* No logging */
+      return FALSE;
+    }
+
+    return TRUE;
+  }
+
+  return FALSE;
+}
+
+
 bool general_log_print(THD *thd, enum enum_server_command command,
                        const char *format, ...)
 {
   va_list args;
   uint error= 0;
 
+  /* Print the message to the buffer if we want to log this king of commands */
+  if (! logger.log_command(thd, command))
+    return FALSE;
+
   va_start(args, format);
   error= logger.general_log_print(thd, command, format, args);
   va_end(args);
@@ -3749,6 +3773,16 @@ bool general_log_print(THD *thd, enum enum_server_command command,
   return error;
 }
 
+bool general_log_write(THD *thd, enum enum_server_command command,
+                       const char *query, uint query_length)
+{
+  /* Write the message to the log if we want to log this king of commands */
+  if (logger.log_command(thd, command))
+    return logger.general_log_write(thd, command, query, query_length);
+
+  return FALSE;
+}
+
 void MYSQL_BIN_LOG::rotate_and_purge(uint flags)
 {
   if (!(flags & RP_LOCK_LOG_IS_ALREADY_LOCKED))
diff --git a/sql/log.h b/sql/log.h
index e597c986794..bef0101c8b5 100644
--- a/sql/log.h
+++ b/sql/log.h
@@ -499,6 +499,8 @@ public:
   void lock_exclusive() { rw_wrlock(&LOCK_logger); }
   void unlock() { rw_unlock(&LOCK_logger); }
   bool is_log_table_enabled(uint log_table_type);
+  bool log_command(THD *thd, enum enum_server_command command);
+
   /*
     We want to initialize all log mutexes as soon as possible,
     but we cannot do it in constructor, as safe_mutex relies on
@@ -518,6 +520,8 @@ public:
                       ulonglong current_utime);
   bool general_log_print(THD *thd,enum enum_server_command command,
                          const char *format, va_list args);
+  bool general_log_write(THD *thd, enum enum_server_command command,
+                         const char *query, uint query_length);
 
   /* we use this function to setup all enabled log event handlers */
   int set_handlers(uint error_log_printer,
diff --git a/sql/log_event.cc b/sql/log_event.cc
index d8e22953fc2..a435894382b 100644
--- a/sql/log_event.cc
+++ b/sql/log_event.cc
@@ -2113,7 +2113,7 @@ START SLAVE; . Query: '%s'", expected_error, thd->query);
 
     /* If the query was not ignored, it is printed to the general log */
     if (thd->net.last_errno != ER_SLAVE_IGNORED_TABLE)
-      general_log_print(thd, COM_QUERY, "%s", thd->query);
+      general_log_write(thd, COM_QUERY, thd->query, thd->query_length);
 
 compare_errors:
 
diff --git a/sql/mysql_priv.h b/sql/mysql_priv.h
index 79d4c16f9c1..08e535548e0 100644
--- a/sql/mysql_priv.h
+++ b/sql/mysql_priv.h
@@ -740,6 +740,9 @@ bool slow_log_print(THD *thd, const char *query, uint query_length,
 bool general_log_print(THD *thd, enum enum_server_command command,
                        const char *format,...);
 
+bool general_log_write(THD *thd, enum enum_server_command command,
+                       const char *query, uint query_length);
+
 #include "sql_class.h"
 #include "sql_acl.h"
 #include "tztime.h"
diff --git a/sql/sp_head.cc b/sql/sp_head.cc
index 7de230bba78..6e0da982369 100644
--- a/sql/sp_head.cc
+++ b/sql/sp_head.cc
@@ -2707,7 +2707,7 @@ sp_instr_stmt::execute(THD *thd, uint *nextp)
       queries with SP vars can't be cached)
     */
     if (unlikely((thd->options & OPTION_LOG_OFF)==0))
-      general_log_print(thd, COM_QUERY, "%s", thd->query);
+      general_log_write(thd, COM_QUERY, thd->query, thd->query_length);
 
     if (query_cache_send_result_to_client(thd,
 					  thd->query, thd->query_length) <= 0)
diff --git a/sql/sql_parse.cc b/sql/sql_parse.cc
index 695e923e816..83ac2ee44dc 100644
--- a/sql/sql_parse.cc
+++ b/sql/sql_parse.cc
@@ -782,7 +782,7 @@ bool dispatch_command(enum enum_server_command command, THD *thd,
 			packet, packet_length, thd->charset());
     if (!mysql_change_db(thd, &tmp, FALSE))
     {
-      general_log_print(thd, command, "%s",thd->db);
+      general_log_write(thd, command, thd->db, thd->db_length);
       send_ok(thd);
     }
     break;
@@ -980,10 +980,9 @@ bool dispatch_command(enum enum_server_command command, THD *thd,
       break;					// fatal error is set
     char *packet_end= thd->query + thd->query_length;
     /* 'b' stands for 'buffer' parameter', special for 'my_snprintf' */
-    const char *format= "%.*b";
     const char* found_semicolon= NULL;
 
-    general_log_print(thd, command, format, thd->query_length, thd->query);
+    general_log_write(thd, command, thd->query, thd->query_length);
     DBUG_PRINT("query",("%-.4096s",thd->query));
 
     if (!(specialflag & SPECIAL_NO_PRIOR))
@@ -1142,7 +1141,7 @@ bool dispatch_command(enum enum_server_command command, THD *thd,
                    ER(ER_LOCK_OR_ACTIVE_TRANSACTION), MYF(0));
 	break;
       }
-      general_log_print(thd, command, db.str);
+      general_log_write(thd, command, db.str, db.length);
       mysql_rm_db(thd, db.str, 0, 0);
       break;
     }
diff --git a/sql/sql_prepare.cc b/sql/sql_prepare.cc
index 05743b6dfe3..a6cdcf14881 100644
--- a/sql/sql_prepare.cc
+++ b/sql/sql_prepare.cc
@@ -2947,12 +2947,7 @@ bool Prepared_statement::prepare(const char *packet, uint packet_len)
       the general log.
     */
     if (thd->spcont == NULL)
-    {
-      const char *format= "[%lu] %.*b";
-      general_log_print(thd, COM_STMT_PREPARE, format, id,
-                        query_length, query);
-
-    }
+      general_log_write(thd, COM_STMT_PREPARE, query, query_length);
   }
   DBUG_RETURN(error);
 }
@@ -3150,11 +3145,7 @@ bool Prepared_statement::execute(String *expanded_query, bool open_cursor)
     the general log.
   */
   if (error == 0 && thd->spcont == NULL)
-  {
-    const char *format= "[%lu] %.*b";
-    general_log_print(thd, COM_STMT_EXECUTE, format, id,
-                      thd->query_length, thd->query);
-  }
+    general_log_write(thd, COM_STMT_EXECUTE, thd->query, thd->query_length);
 
 error:
   flags&= ~ (uint) IS_IN_USE;