Nebula 1/Nebula One.iso/Misc/msql-1.0.6/src/msql/net.c

C/C++ Source or Header | 1995-02-14 | 4.4 KB | 250 lines

/*
**    net.c    -
**
**
** Copyright (c) 1993  David J. Hughes
**
** Permission to use, copy, and distribute for non-commercial purposes,
** is hereby granted without fee, providing that the above copyright
** notice appear in all copies and that both the copyright notice and this
** permission notice appear in supporting documentation.
**
** This software is provided "as is" without any expressed or implied warranty.
**
** ID = "$Id:"
**
*/


#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <signal.h>
#include <netdb.h>

#include <common/portability.h>
#include "msql_priv.h"


static     u_char    packetBuf[PKT_LEN + 4];
static    int    readTimeout;
u_char    *packet = NULL;


intToBuf(cp,val)
        u_char  *cp;
        int     val;
{
        *cp++ = (unsigned int)(val & 0x000000ff);
        *cp++ = (unsigned int)(val & 0x0000ff00) >> 8;
        *cp++ = (unsigned int)(val & 0x00ff0000) >> 16;
        *cp++ = (unsigned int)(val & 0xff000000) >> 24;
}


bufToInt(cp)
        u_char  *cp;
{
        int val;

        val = 0;
        val = *cp++;
        val += ((int) *cp++) << 8 ;
        val += ((int) *cp++) << 16;
        val += ((int) *cp++) << 24;
        return(val);
}


initNet()
{
    packet = (u_char *)packetBuf + 4;
}



void writePkt(fd)
    int    fd;
{
    u_char    *cp;
    int    len,
        offset,
        remain,
        numBytes;

    len = strlen(packet);
    intToBuf(packetBuf,len);
    offset = 0;
    remain = len+4;
    while(remain > 0)
    {
        numBytes = write(fd,packetBuf + offset, remain);
        if (numBytes == -1)
        {
            return;
        }
        offset += numBytes;
        remain -= numBytes;
    }
}


RETSIGTYPE alarmHandler(sig)
    int    sig;
{
    readTimeout = 1;
}


int readPkt(fd)
    int    fd;
{
    u_char    *c,
        buf[4];
    int    len,
        remain,
        offset,
        numBytes;
    static    int init = 1;

#ifdef MSQL_SERVER
    if (init)
    {
        signal(SIGALRM,alarmHandler);
        init = 0;
    }
    alarm(10);
#endif
    readTimeout = 0;
    remain = 4;
    offset = 0;
    while(remain > 0)
    {
        numBytes = read(fd,buf + offset,remain);
        if(numBytes <= 0)
        {
            alarm(0);
                 return(-1);
        }
        remain -= numBytes;
        offset += numBytes;

    }
#ifdef MSQL_SERVER
    if (readTimeout)
    {
        alarm(0);
        return(-1);
    }
#endif
    len = bufToInt(buf);
    if (len > PKT_LEN)
    {
        fprintf(stderr,"Packet too large (%d)\n", len);
        alarm(0);
        return(-1);
    }
    remain = len;
    offset = 0;
    while(remain > 0)
    {
        numBytes = read(fd,packet+offset,remain);
        if (readTimeout)
        {
            alarm(0);
            return(-1);
        }
        if (numBytes <= 0)
        {
            alarm(0);
                 return(-1);
        }
        remain -= numBytes;
        offset += numBytes;
    }
    *(packet+offset) = 0;
#ifdef MSQL_SERVER
    alarm(0);
#endif
        return(len);
}



/***********************************************************************
 *
 * This section of code contains machine-specific code for handling integers.
 * Msql supports 32 bit 2's complement integers.  To hide the details of
 * converting integers for specific machines, the routines packInt32() and
 * unpackInt32() were written.  If you have a machine that has native ints
 * other than 32 bit 2's complement, you must either write your own versions
 * of packInt32() and unpackInt32(), or modify the supplied ones.  For any
 * machine using 2's complement ints, simple changes to the
 * BYTES_PER_INT, HIGH_BITS, HIGH_BITS_MASK, and SIGN_BIT_MASK macros should
 * make your code work.  If you have something else, you're on your own ...
 *
 ************************************************************************/

#if _CRAY
#define BYTES_PER_INT    8
#endif

#ifndef BYTES_PER_INT
#define BYTES_PER_INT    4        /* default.  most boxes fit here */
#endif

#if BYTES_PER_INT == 8
#define BIG_INTS    1
#define HIGH_BITS    32            /* bits-per-int minus 32 */
#define HIGH_BITS_MASK    0xffffffff00000000    /* mask of the high bits */
#define SIGN_BIT_MASK    0x0000000080000000      /* mask of your sign bit */
#endif

#if BYTES_PER_INT == 4
#define BIG_INTS          0
#endif

/*
 * Pack a native integer into a character buffer.  The buffer is assumed
 * to be at least 4 bytes long.
 */

int
packInt32(num, buf)
int    num;
char    *buf;
{
#if BIG_INTS
    num <<= HIGH_BITS;
#endif

    bcopy((char *)&num, buf, 4);
    return 0;
}

/*
 * Extract a native integer from a character buffer.  The buffer is assumed
 * to have been formatted using the packInt32() routine.
 */

int
unpackInt32(buf)
char    *buf;
{
    int    num;

    bcopy(buf, (char *)&num, 4);

#if BIG_INTS
    num >>= HIGH_BITS;

    if (num & SIGN_BIT_MASK) {
        num |= HIGH_BITS_MASK;
    }
#endif

    return num;
}