mariadb/sql/sql_binlog.cc

/* Copyright (C) 2005-2006 MySQL 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 */

#include "mysql_priv.h"
#include "rpl_rli.h"
#include "base64.h"

/*
  Execute a BINLOG statement

  TODO: This currently assumes a MySQL 5.x binlog.
  When we'll have binlog with a different format, to execute the
  BINLOG command properly the server will need to know which format
  the BINLOG command's event is in.  mysqlbinlog should then send
  the Format_description_log_event of the binlog it reads and the
  server thread should cache this format into
  rli->description_event_for_exec.
*/

void mysql_client_binlog_statement(THD* thd)
{
  DBUG_ENTER("mysql_client_binlog_statement");
  DBUG_PRINT("info",("binlog base64: '%*s'",
                     (int) (thd->lex->comment.length < 2048 ?
                            thd->lex->comment.length : 2048),
                     thd->lex->comment.str));

  if (check_global_access(thd, SUPER_ACL))
    DBUG_VOID_RETURN;

  size_t coded_len= thd->lex->comment.length + 1;
  size_t decoded_len= base64_needed_decoded_length(coded_len);
  DBUG_ASSERT(coded_len > 0);

  /*
    Allocation
  */
  if (!thd->rli_fake)
    thd->rli_fake= new Relay_log_info;

  const Format_description_log_event *desc=
    new Format_description_log_event(4);

  const char *error= 0;
  char *buf= (char *) my_malloc(decoded_len, MYF(MY_WME));
  Log_event *ev = 0;

  /*
    Out of memory check
  */
  if (!(thd->rli_fake && desc && buf))
  {
    my_error(ER_OUTOFMEMORY, MYF(0), 1);  /* needed 1 bytes */
    goto end;
  }

  thd->rli_fake->sql_thd= thd;
  thd->rli_fake->no_storage= TRUE;

  for (char const *strptr= thd->lex->comment.str ;
       strptr < thd->lex->comment.str + thd->lex->comment.length ; )
  {
    char const *endptr= 0;
    int bytes_decoded= base64_decode(strptr, coded_len, buf, &endptr);

#ifndef HAVE_purify
      /*
        This debug printout should not be used for valgrind builds
        since it will read from unassigned memory.
      */
    DBUG_PRINT("info",
               ("bytes_decoded: %d  strptr: 0x%lx  endptr: 0x%lx ('%c':%d)",
                bytes_decoded, (long) strptr, (long) endptr, *endptr,
                *endptr));
#endif

    if (bytes_decoded < 0)
    {
      my_error(ER_BASE64_DECODE_ERROR, MYF(0));
      goto end;
    }
    else if (bytes_decoded == 0)
      break; // If no bytes where read, the string contained only whitespace

    DBUG_ASSERT(bytes_decoded > 0);
    DBUG_ASSERT(endptr > strptr);
    coded_len-= endptr - strptr;
    strptr= endptr;

    /*
      Now we have one or more events stored in the buffer. The size of
      the buffer is computed based on how much base64-encoded data
      there were, so there should be ample space for the data (maybe
      even too much, since a statement can consist of a considerable
      number of events).

      TODO: Switch to use a stream-based base64 encoder/decoder in
      order to be able to read exactly what is necessary.
    */

    DBUG_PRINT("info",("binlog base64 decoded_len: %lu  bytes_decoded: %d",
                       (ulong) decoded_len, bytes_decoded));

    /*
      Now we start to read events of the buffer, until there are no
      more.
    */
    for (char *bufptr= buf ; bytes_decoded > 0 ; )
    {
      /*
        Checking that the first event in the buffer is not truncated.
      */
      ulong event_len= uint4korr(bufptr + EVENT_LEN_OFFSET);
      DBUG_PRINT("info", ("event_len=%lu, bytes_decoded=%d",
                          event_len, bytes_decoded));
      if (bytes_decoded < EVENT_LEN_OFFSET || (uint) bytes_decoded < event_len)
      {
        my_error(ER_SYNTAX_ERROR, MYF(0));
        goto end;
      }

      ev= Log_event::read_log_event(bufptr, event_len, &error, desc);

      DBUG_PRINT("info",("binlog base64 err=%s", error));
      if (!ev)
      {
        /*
          This could actually be an out-of-memory, but it is more likely
          causes by a bad statement
        */
        my_error(ER_SYNTAX_ERROR, MYF(0));
        goto end;
      }

      bytes_decoded -= event_len;
      bufptr += event_len;

      DBUG_PRINT("info",("ev->get_type_code()=%d", ev->get_type_code()));
#ifndef HAVE_purify
      /*
        This debug printout should not be used for valgrind builds
        since it will read from unassigned memory.
      */
      DBUG_PRINT("info",("bufptr+EVENT_TYPE_OFFSET: 0x%lx",
                         (long) (bufptr+EVENT_TYPE_OFFSET)));
      DBUG_PRINT("info", ("bytes_decoded: %d   bufptr: 0x%lx  buf[EVENT_LEN_OFFSET]: %lu",
                          bytes_decoded, (long) bufptr,
                          (ulong) uint4korr(bufptr+EVENT_LEN_OFFSET)));
#endif
      ev->thd= thd;
      /*
        We go directly to the application phase, since we don't need
        to check if the event shall be skipped or not.

        Neither do we have to update the log positions, since that is
        not used at all: the rli_fake instance is used only for error
        reporting.
       */
#if !defined(MYSQL_CLIENT) && defined(HAVE_REPLICATION)
      if (IF_DBUG(int err= ) ev->apply_event(thd->rli_fake))
      {
        DBUG_PRINT("info", ("apply_event() returned: %d", err));
        /*
          TODO: Maybe a better error message since the BINLOG statement
          now contains several events.
        */
        my_error(ER_UNKNOWN_ERROR, MYF(0), "Error executing BINLOG statement");
        goto end;
      }
#endif

      delete ev;
      ev= 0;
    }
  }


  DBUG_PRINT("info",("binlog base64 execution finished successfully"));
  send_ok(thd);

end:
  delete desc;
  my_free(buf, MYF(MY_ALLOW_ZERO_PTR));
  DBUG_VOID_RETURN;
}