socket.c

关系型数据库 Postgresql 6.5.2

/* Module:          socket.c
 *
 * Description:     This module contains functions for low level socket
 *                  operations (connecting/reading/writing to the backend)
 *
 * Classes:         SocketClass (Functions prefix: "SOCK_")
 *
 * API functions:   none
 *
 * Comments:        See "notice.txt" for copyright and license information.
 *
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include "socket.h"

#ifndef WIN32
#include <stdlib.h>
#include <string.h>	/* for memset */
#endif

extern GLOBAL_VALUES globals;

#ifndef BOOL
#define BOOL	int
#endif
#ifndef TRUE
#define TRUE	(BOOL)1
#endif
#ifndef FALSE
#define FALSE	(BOOL)0
#endif


void
SOCK_clear_error(SocketClass *self)
{
	self->errornumber = 0; 
	self->errormsg = NULL; 
}

SocketClass * 
SOCK_Constructor()
{
SocketClass *rv;

    rv = (SocketClass *) malloc(sizeof(SocketClass));

    if (rv != NULL) {
		rv->socket = (SOCKETFD) -1;
		rv->buffer_filled_in = 0;
		rv->buffer_filled_out = 0;
		rv->buffer_read_in = 0;

		rv->buffer_in = (unsigned char *) malloc(globals.socket_buffersize);
		if ( ! rv->buffer_in)
			return NULL;

		rv->buffer_out = (unsigned char *) malloc(globals.socket_buffersize);
		if ( ! rv->buffer_out)
			return NULL;
		
        rv->errormsg = NULL;
        rv->errornumber = 0;

		rv->reverse = FALSE;
    } 
    return rv;

}

void
SOCK_Destructor(SocketClass *self)
{
	if (self->socket != -1) {
		if ( ! shutdown(self->socket, 2)) /* no sends or receives */
			closesocket(self->socket);
	}

	if (self->buffer_in)
		free(self->buffer_in);

	if (self->buffer_out)
		free(self->buffer_out);

	free(self);

}


char 
SOCK_connect_to(SocketClass *self, unsigned short port, char *hostname)
{
struct hostent *host;
struct sockaddr_in sadr;
unsigned long iaddr;

	if (self->socket != -1) {
		self->errornumber = SOCKET_ALREADY_CONNECTED;
		self->errormsg = "Socket is already connected";
		return 0;
	}

	memset((char *)&sadr, 0, sizeof(sadr));

	/*	If it is a valid IP address, use it.
		Otherwise use hostname lookup. 
	*/
	iaddr = inet_addr(hostname);
	if (iaddr == INADDR_NONE) {
		host = gethostbyname(hostname);
		if (host == NULL) {
			self->errornumber = SOCKET_HOST_NOT_FOUND;
			self->errormsg = "Could not resolve hostname.";
			return 0;
		}
		memcpy(&(sadr.sin_addr), host->h_addr, host->h_length);
	}
	else
		memcpy(&(sadr.sin_addr), (struct in_addr *) &iaddr, sizeof(iaddr));

	sadr.sin_family = AF_INET;
	sadr.sin_port = htons(port);

	self->socket = socket(AF_INET, SOCK_STREAM, 0);
	if (self->socket == -1) {
		self->errornumber = SOCKET_COULD_NOT_CREATE_SOCKET;
		self->errormsg = "Could not create Socket.";
		return 0;
	}

	if ( connect(self->socket, (struct sockaddr *)&(sadr),
			sizeof(sadr))  < 0) {

		self->errornumber = SOCKET_COULD_NOT_CONNECT;
		self->errormsg = "Could not connect to remote socket.";
		closesocket(self->socket);
		self->socket = (SOCKETFD) -1;
		return 0;
	}
	return 1;
}


void 
SOCK_get_n_char(SocketClass *self, char *buffer, int len)
{
int lf;

	if ( ! buffer) {
		self->errornumber = SOCKET_NULLPOINTER_PARAMETER;
		self->errormsg = "get_n_char was called with NULL-Pointer";
		return;
	}

	for(lf=0; lf < len; lf++)
		buffer[lf] = SOCK_get_next_byte(self);
}


void 
SOCK_put_n_char(SocketClass *self, char *buffer, int len)
{
int lf;

	if ( ! buffer) {
		self->errornumber = SOCKET_NULLPOINTER_PARAMETER;
		self->errormsg = "put_n_char was called with NULL-Pointer";
		return;
	}

	for(lf=0; lf < len; lf++)
		SOCK_put_next_byte(self, (unsigned char)buffer[lf]);
}


/*  bufsize must include room for the null terminator 
	will read at most bufsize-1 characters + null. 
*/
void 
SOCK_get_string(SocketClass *self, char *buffer, int bufsize)
{
register int lf = 0;

	for (lf = 0; lf < bufsize; lf++)
		if ( ! (buffer[lf] = SOCK_get_next_byte(self)))
			return;
		
	buffer[bufsize-1] = '\0';
}


void 
SOCK_put_string(SocketClass *self, char *string)
{
register int lf;
int len;

	len = strlen(string)+1;

	for(lf = 0; lf < len; lf++)
		SOCK_put_next_byte(self, (unsigned char)string[lf]);
}


int 
SOCK_get_int(SocketClass *self, short len)
{
char buf[4];

	switch (len) {
	case 2:
		SOCK_get_n_char(self, buf, len);
		if (self->reverse)
			return *((unsigned short *) buf);
		else
			return ntohs( *((unsigned short *) buf) );

	case 4:
		SOCK_get_n_char(self, buf, len);
		if (self->reverse)
			return *((unsigned int *) buf);
		else
			return ntohl( *((unsigned int *) buf) );

	default:
		self->errornumber = SOCKET_GET_INT_WRONG_LENGTH;
		self->errormsg = "Cannot read ints of that length";
		return 0;
	}
}


void 
SOCK_put_int(SocketClass *self, int value, short len)
{
unsigned int rv;

	switch (len) {
	case 2:
		rv = self->reverse ? value : htons( (unsigned short) value);
		SOCK_put_n_char(self, (char *) &rv, 2);
		return;

	case 4:
		rv = self->reverse ? value : htonl( (unsigned int) value);
		SOCK_put_n_char(self, (char *) &rv, 4);
		return;

	default:
		self->errornumber = SOCKET_PUT_INT_WRONG_LENGTH;
		self->errormsg = "Cannot write ints of that length";
		return;
	 }
}


void 
SOCK_flush_output(SocketClass *self)
{
int written;

	written = send(self->socket, (char *)self->buffer_out, self->buffer_filled_out, 0);
	if (written != self->buffer_filled_out) {
		self->errornumber = SOCKET_WRITE_ERROR;
		self->errormsg = "Could not flush socket buffer.";
	}
	self->buffer_filled_out = 0;
}

unsigned char 
SOCK_get_next_byte(SocketClass *self)
{

	if (self->buffer_read_in >= self->buffer_filled_in) {
	// there are no more bytes left in the buffer ->
	// reload the buffer

		self->buffer_read_in = 0;
		self->buffer_filled_in = recv(self->socket, (char *)self->buffer_in, globals.socket_buffersize, 0);

		mylog("read %d, global_socket_buffersize=%d\n", self->buffer_filled_in, globals.socket_buffersize);

		if (self->buffer_filled_in == -1) {
			self->errornumber = SOCKET_READ_ERROR;
			self->errormsg = "Error while reading from the socket.";
			self->buffer_filled_in = 0;
		}
		if (self->buffer_filled_in == 0) {
			self->errornumber = SOCKET_CLOSED;
			self->errormsg = "Socket has been closed.";
			self->buffer_filled_in = 0;
		}

	}
	return self->buffer_in[self->buffer_read_in++];
}

void 
SOCK_put_next_byte(SocketClass *self, unsigned char next_byte)
{
int bytes_sent;

	self->buffer_out[self->buffer_filled_out++] = next_byte;

	if (self->buffer_filled_out == globals.socket_buffersize) {
		// buffer is full, so write it out
		bytes_sent = send(self->socket, (char *)self->buffer_out, globals.socket_buffersize, 0);
		if (bytes_sent != globals.socket_buffersize) {
			self->errornumber = SOCKET_WRITE_ERROR;
			self->errormsg = "Error while writing to the socket.";
		}
		self->buffer_filled_out = 0;
	}
}