libmariadb/libmariadb/ma_net.c

/* Copyright (C) 2000 MySQL AB & MySQL Finland AB & TCX DataKonsult AB
   2012-2016 SkySQL AB, MariaDB Corporation AB
   This library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Library General Public
   License as published by the Free Software Foundation; either
   version 2 of the License, or (at your option) any later version.

   This library 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
   Library General Public License for more details.

   You should have received a copy of the GNU Library General Public
   License along with this library; if not, write to the Free
   Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
   MA 02111-1301, USA */

/* Write and read of logical packets to/from socket
 ** Writes are cached into net_buffer_length big packets.
 ** Read packets are reallocated dynamically when reading big packets.
 ** Each logical packet has the following pre-info:
 ** 3 byte length & 1 byte package-number.
 */


#include <ma_global.h>
#include <mysql.h>
#include <ma_pvio.h>
#include <ma_sys.h>
#include <ma_string.h>
#include "mysql.h"
#include "ma_server_error.h"
#include <signal.h>
#include <errno.h>
#include <sys/types.h>
#include <ma_pvio.h>
#include <ma_common.h>
#ifndef _WIN32
#include <poll.h>
#endif

#define MAX_PACKET_LENGTH (256L*256L*256L-1)

/* net_buffer_length and max_allowed_packet are defined in mysql.h
   See bug conc-57
 */
#undef net_buffer_length

#undef max_allowed_packet
ulong max_allowed_packet=1024L * 1024L * 1024L;
ulong net_read_timeout=  NET_READ_TIMEOUT;
ulong net_write_timeout= NET_WRITE_TIMEOUT;
ulong net_buffer_length= 8192;	/* Default length. Enlarged if necessary */

#if !defined(_WIN32)
#include <sys/socket.h>
#else
#undef MYSQL_SERVER			/* Win32 can't handle interrupts */
#endif
#if !defined(_WIN32) && !defined(HAVE_BROKEN_NETINET_INCLUDES) && !defined(__BEOS__)
#include <netinet/in_systm.h>
#include <netinet/in.h>
#include <netinet/ip.h>
#if !defined(alpha_linux_port)
#include <netinet/tcp.h>
#endif
#endif


/*
 ** Give error if a too big packet is found
 ** The server can change this with the -O switch, but because the client
 ** can't normally do this the client should have a bigger max-buffer.
 */

static int ma_net_write_buff(NET *net,const char *packet, size_t len);


/* Init with packet info */

int ma_net_init(NET *net, MARIADB_PVIO* pvio)
{
  if (!(net->buff=(uchar*) malloc(net_buffer_length)))
    return 1;
  if (!net->extension)
    return 1;

  memset(net->buff, 0, net_buffer_length);

  net->max_packet_size= MAX(net_buffer_length, max_allowed_packet);
  net->buff_end=net->buff+(net->max_packet=net_buffer_length);
  net->pvio = pvio;
  net->error=0; net->return_status=0;
  net->read_timeout=(uint) net_read_timeout;		/* Timeout for read */
  net->compress_pkt_nr= net->pkt_nr= 0;
  net->write_pos=net->read_pos = net->buff;
  net->last_error[0]= net->sqlstate[0] =0;

  net->compress=0; net->reading_or_writing=0;
  net->where_b = net->remain_in_buf=0;
  net->last_errno=0;

  if (pvio != 0)					/* If real connection */
  {
    ma_pvio_get_handle(pvio, &net->fd);
    ma_pvio_blocking(pvio, 1, 0);
    ma_pvio_fast_send(pvio);
  }
  return 0;
}

void ma_net_end(NET *net)
{
  free(net->buff);
  net->buff=0;
}

/* Realloc the packet buffer */

static my_bool net_realloc(NET *net, size_t length)
{
  uchar *buff;
  size_t pkt_length;

  if (length >= net->max_packet_size)
  {
    net->error=1;
    net->last_errno=ER_NET_PACKET_TOO_LARGE;
    return(1);
  }
  pkt_length = (length+IO_SIZE-1) & ~(IO_SIZE-1);
  /* reallocate buffer:
     size= pkt_length + NET_HEADER_SIZE + COMP_HEADER_SIZE */
  if (!(buff=(uchar*) realloc(net->buff,
          pkt_length + NET_HEADER_SIZE + COMP_HEADER_SIZE)))
  {
    net->error=1;
    return(1);
  }
  net->buff=net->write_pos=buff;
  net->buff_end=buff+(net->max_packet=(unsigned long)pkt_length);
  return(0);
}

/* Remove unwanted characters from connection */
void ma_net_clear(NET *net)
{
  if (net->extension->multi_status > COM_MULTI_OFF)
    return;
  net->compress_pkt_nr= net->pkt_nr=0;				/* Ready for new command */
  net->write_pos=net->buff;
  return;
}

/* Flush write_buffer if not empty. */
int ma_net_flush(NET *net)
{
  int error=0;

  /* don't flush if pipelined query is in progress */
  if (net->extension->multi_status > COM_MULTI_OFF)
    return 0;

  if (net->buff != net->write_pos)
  {
    error=ma_net_real_write(net,(char*) net->buff,
        (size_t) (net->write_pos - net->buff));
    net->write_pos=net->buff;
  }
  if (net->compress)
    net->pkt_nr= net->compress_pkt_nr;
  return(error);
}

/*****************************************************************************
 ** Write something to server/client buffer
 *****************************************************************************/

/*
 ** Write a logical packet with packet header
 ** Format: Packet length (3 bytes), packet number(1 byte)
 **         When compression is used a 3 byte compression length is added
 ** NOTE: If compression is used the original package is destroyed!
 */

int ma_net_write(NET *net, const uchar *packet, size_t len)
{
  uchar buff[NET_HEADER_SIZE];
  while (len >= MAX_PACKET_LENGTH)
  {
    const ulong max_len= MAX_PACKET_LENGTH;
    int3store(buff,max_len);
    buff[3]= (uchar)net->pkt_nr++;
    if (ma_net_write_buff(net,(char*) buff,NET_HEADER_SIZE) ||
        ma_net_write_buff(net, (char *)packet, max_len))
      return 1;
    packet+= max_len;
    len-= max_len;
  }
  /* write last remaining packet, size can be zero */
  int3store(buff, len);
  buff[3]= (uchar)net->pkt_nr++;
  if (ma_net_write_buff(net,(char*) buff,NET_HEADER_SIZE) ||
      ma_net_write_buff(net, (char *)packet, len))
    return 1;
  return 0;
}

int ma_net_write_command(NET *net, uchar command,
    const char *packet, size_t len,
    my_bool disable_flush)
{
  uchar buff[NET_HEADER_SIZE+1];
  size_t buff_size= NET_HEADER_SIZE + 1;
  size_t length= 1 + len; /* 1 extra byte for command */
  int rc;

  buff[NET_HEADER_SIZE]= 0;
  buff[4]=command;

  if (length >= MAX_PACKET_LENGTH)
  {
    len= MAX_PACKET_LENGTH - 1;
    do
    {
      int3store(buff, MAX_PACKET_LENGTH);
      buff[3]= (net->compress) ? 0 : (uchar) (net->pkt_nr++);

      if (ma_net_write_buff(net, (char *)buff, buff_size) ||
          ma_net_write_buff(net, packet, len))
        return(1);
      packet+= len;
      length-= MAX_PACKET_LENGTH;
      len= MAX_PACKET_LENGTH;
      buff_size= NET_HEADER_SIZE; /* don't send command for further packets */
    } while (length >= MAX_PACKET_LENGTH);
    len= length;
  }
  int3store(buff,length);
  buff[3]= (net->compress) ? 0 :(uchar) (net->pkt_nr++);
  rc= test (ma_net_write_buff(net,(char *)buff, buff_size) ||
      ma_net_write_buff(net,packet,len));
  if (!rc && !disable_flush)
    return test(ma_net_flush(net));
  return rc;
}


static int ma_net_write_buff(NET *net,const char *packet, size_t len)
{
  size_t left_length;

  if (!len)
    return 0;

  if (net->max_packet > MAX_PACKET_LENGTH &&
      net->compress)
    left_length= (size_t)(MAX_PACKET_LENGTH - (net->write_pos - net->buff));
  else
    left_length=(size_t) (net->buff_end - net->write_pos);

  if (len > left_length)
  {
    if (net->write_pos != net->buff)
    {
      memcpy((char*) net->write_pos,packet,left_length);
      if (ma_net_real_write(net,(char*) net->buff,
            (size_t)(net->write_pos - net->buff) + left_length))
        return 1;
      packet+=left_length;
      len-=left_length;
      net->write_pos= net->buff;
    }
    if (net->compress)
    {
      /* uncompressed length is stored in 3 bytes,so
         packet can't be > 0xFFFFFF */
      left_length= MAX_PACKET_LENGTH;
      while (len > left_length)
      {
        if (ma_net_real_write(net, packet, left_length))
          return 1;
        packet+= left_length;
        len-= left_length;
      }
    }
    if (len > net->max_packet)
      return(test(ma_net_real_write(net, packet, len)));
  }
  memcpy((char*) net->write_pos,packet,len);
  net->write_pos+=len;
  return 0;
}

unsigned char *mysql_net_store_length(unsigned char *packet, size_t length);

/*  Read and write using timeouts */

int ma_net_real_write(NET *net, const char *packet, size_t len)
{
  ssize_t length;
  char *pos,*end;

  if (net->error == 2)
    return(-1);				/* socket can't be used */

  net->reading_or_writing=2;
#ifdef HAVE_COMPRESS
  if (net->compress)
  {
    size_t complen;
    uchar *b;
    uint header_length=NET_HEADER_SIZE+COMP_HEADER_SIZE;
    if (!(b=(uchar*) malloc(len + NET_HEADER_SIZE + COMP_HEADER_SIZE + 1)))
    {
      net->last_errno=ER_OUT_OF_RESOURCES;
      net->error=2;
      net->reading_or_writing=0;
      return(1);
    }
    memcpy(b+header_length,packet,len);

    if (_mariadb_compress((unsigned char*) b+header_length,&len,&complen))
    {
      complen=0;
    }
    int3store(&b[NET_HEADER_SIZE],complen);
    int3store(b,len);
    b[3]=(uchar) (net->compress_pkt_nr++);
    len+= header_length;
    packet= (char*) b;
  }
#endif /* HAVE_COMPRESS */

  pos=(char*) packet; end=pos+len;
  while (pos != end)
  {
    if ((length=ma_pvio_write(net->pvio,(uchar *)pos,(size_t) (end-pos))) <= 0)
    {
      net->error=2;				/* Close socket */
      net->last_errno= ER_NET_ERROR_ON_WRITE;
      net->reading_or_writing=0;
#ifdef HAVE_COMPRESS
      if (net->compress)
        free((char*) packet);
#endif
      return(1);
    }
    pos+=length;
  }
#ifdef HAVE_COMPRESS
  if (net->compress)
    free((char*) packet);
#endif
  net->reading_or_writing=0;
  return(((int) (pos != end)));
}

/*****************************************************************************
 ** Read something from server/clinet
 *****************************************************************************/
static ulong ma_real_read(NET *net, size_t *complen)
{
  uchar *pos;
  ssize_t length;
  uint i;
  ulong len=packet_error;
  size_t remain= (net->compress ? NET_HEADER_SIZE+COMP_HEADER_SIZE :
      NET_HEADER_SIZE);
  *complen = 0;

  net->reading_or_writing=1;

  pos = net->buff + net->where_b;		/* net->packet -4 */
  for (i=0 ; i < 2 ; i++)
  {
    while (remain > 0)
    {
      /* First read is done with non blocking mode */
      if ((length=ma_pvio_cache_read(net->pvio, pos,remain)) <= 0L)
      {
        len= packet_error;
        net->error=2;				/* Close socket */
        goto end;
      }
      remain -= (ulong) length;
      pos+= (ulong) length;
    }

    if (i == 0)
    {					/* First parts is packet length */
      ulong helping;
      net->pkt_nr= net->buff[net->where_b + 3];
      net->compress_pkt_nr= ++net->pkt_nr;
#ifdef HAVE_COMPRESS
      if (net->compress)
      {
        /* complen is > 0 if package is really compressed */
        *complen=uint3korr(&(net->buff[net->where_b + NET_HEADER_SIZE]));
      }
#endif

      len=uint3korr(net->buff+net->where_b);
      if (!len)
        goto end;
      helping = max(len,(ulong)*complen) + net->where_b;
      /* The necessary size of net->buff */
      if (helping >= net->max_packet)
      {
        if (net_realloc(net, helping))
        {
          len= packet_error;		/* Return error */
          goto end;
        }
      }
      pos=net->buff + net->where_b;
      remain = len;
    }
  }

end:
  net->reading_or_writing=0;
  return(len);
}

ulong ma_net_read(NET *net)
{
  size_t len,complen;

#ifdef HAVE_COMPRESS
  if (!net->compress)
  {
#endif
    len = ma_real_read (net,(size_t *)&complen);
    if (len == MAX_PACKET_LENGTH)
    {
      /* multi packet read */
      size_t length= 0;
      ulong last_pos= net->where_b;

      do
      {
        length+= len;
        net->where_b+= (unsigned long)len;
        len= ma_real_read(net, &complen);
      } while (len == MAX_PACKET_LENGTH);
      net->where_b= last_pos;
      if (len != packet_error)
        len+= length;
    }
    net->read_pos = net->buff + net->where_b;
    if (len != packet_error)
      net->read_pos[len]=0;		/* Safeguard for mysql_use_result */
    return (ulong)len;
#ifdef HAVE_COMPRESS
  }
  else
  {
    /*
       compressed protocol:

       --------------------------------------
       packet_length       3
       sequence_id         1
       uncompressed_length 3
       --------------------------------------
       compressed data     packet_length - 7
       --------------------------------------

       Another packet will follow if:
       packet_length == MAX_PACKET_LENGTH

       Last package will be identified by
       - packet_length is zero (special case)
       - packet_length < MAX_PACKET_LENGTH
     */

    size_t packet_length,
           buffer_length;
    size_t current= 0, start= 0;
    my_bool is_multi_packet= 0;

    /* check if buffer is empty */
    if (!net->remain_in_buf)
    {
      buffer_length= 0;
    }
    else
    {
      /* save position and restore \0 character */
      buffer_length= net->buf_length;
      current= net->buf_length - net->remain_in_buf;
      start= current;
      net->buff[net->buf_length - net->remain_in_buf]=net->save_char;
    }
    for (;;)
    {
      if (buffer_length - current >= 4)
      {
        uchar *pos= net->buff + current;
        packet_length= uint3korr(pos);

        /* check if we have last package (special case: zero length) */
        if (!packet_length)
        {
          current+= 4; /* length + sequence_id,
                          no more data will follow */
          break;
        }
        if (packet_length + 4 <= buffer_length - current)
        {
          if (!is_multi_packet)
          {
            current= current + packet_length + 4;
          }
          else
          {
            /* remove packet_header */
            memmove(net->buff + current,
                net->buff + current + 4,
                buffer_length - current);
            buffer_length-= 4;
            current+= packet_length;
          }
          /* do we have last packet ? */
          if (packet_length != MAX_PACKET_LENGTH)
          {
            is_multi_packet= 0;
            break;
          }
          else
            is_multi_packet= 1;
          if (start)
          {
            memmove(net->buff, net->buff + start,
                buffer_length - start);
            /* decrease buflen*/
            buffer_length-= start;
            start= 0;
          }
          continue;
        }
      }
      if (start)
      {
        memmove(net->buff, net->buff + start, buffer_length - start);
        /* decrease buflen and current */
        current -= start;
        buffer_length-= start;
        start= 0;
      }

      net->where_b=(unsigned long)buffer_length;

      if ((packet_length = ma_real_read(net,(size_t *)&complen)) == packet_error)
        return packet_error;
      if (_mariadb_uncompress((unsigned char*) net->buff + net->where_b, &packet_length, &complen))
      {
        net->error=2;			/* caller will close socket */
        net->last_errno=ER_NET_UNCOMPRESS_ERROR;
        break;
        return packet_error;
      }
      buffer_length+= complen;
    }
    /* set values */
    net->buf_length= (unsigned long)buffer_length;
    net->remain_in_buf= (unsigned long)(buffer_length - current);
    net->read_pos= net->buff + start + 4;
    len= current - start - 4;
    if (is_multi_packet)
      len-= 4;
    net->save_char= net->read_pos[len];	/* Must be saved */
    net->read_pos[len]=0;		/* Safeguard for mysql_use_result */
  }
#endif
  return (ulong)len;
}

int net_add_multi_command(NET *net, uchar command, const uchar *packet,
    size_t length)
{
  if (net->extension->multi_status == COM_MULTI_OFF)
  {
    return(1);
  }
  /* don't increase packet number */
  net->compress_pkt_nr= net->pkt_nr= 0;
  return ma_net_write_command(net, command, (const char *)packet, length, 1);
}