server2.c

接着上传带出错处理机制的linux环境下的网络编程-TCPserver端的流程程序

/* server.c */
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <ctype.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <stdlib.h>
#include <errno.h>
#define MAXLINE 80
int             port = 8000;

int
main( void )
{
    struct sockaddr_in sin;
    struct sockaddr_in pin;
    int             listen_fd;
    int             conn_fd;
    int             address_size;
    char            buf[MAXLINE];
    char            str[INET_ADDRSTRLEN];
    int             i;
    int             n;
    int             len;

    bzero( &sin, sizeof( sin ) );
    sin.sin_family = AF_INET;
    sin.sin_addr.s_addr = INADDR_ANY;
    sin.sin_port = htons( port );

    listen_fd = socket( AF_INET, SOCK_STREAM, 0 );
    if ( listen_fd == -1 )
    {
        perror( "call to socket" );
        exit( 1 );
    }
    n = bind( listen_fd, ( struct sockaddr * ) &sin, sizeof( sin ) );
    if ( n == -1 )
    {
        perror( "call to bind" );
        exit( 1 );
    }
    n = listen( listen_fd, 20 );
    if ( n == -1 )
    {
        perror( "call to listen" ), exit( 1 );
    }
    printf( "Accepting connections ...\n" );

    while ( 1 )
    {
        conn_fd =
            accept( listen_fd, ( struct sockaddr * ) &pin, &address_size );
        if ( conn_fd == -1 )
        {
            perror( "call to accept" );
            exit( 1 );
        }
      readagain:
        n = read( conn_fd, buf, MAXLINE );
        if ( n == -1 )
        {
            if ( errno == EINTR )
            {
                goto readagain;
            }
            else
            {
                perror( "call to read" );
                exit( 1 );
            }
        }
        else if ( n == 0 )
        {
            printf( "the other side has been closed.\n" );
            close( conn_fd );
            continue;
        }
        printf( "received from client %s at port %d: %s\n",
                inet_ntop( AF_INET, &pin.sin_addr, str, sizeof( str ) ),
                ntohs( pin.sin_port ), buf );

        // just convert the characters to upper case
        len = strlen( buf );
        for ( i = 0; i < len; i++ )
        {
            buf[i] = toupper( buf[i] );
        }
      writeagain:
        n = write( conn_fd, buf, len + 1 );
        if ( n == -1 )
        {
            if ( errno == EINTR )
            {
                goto writeagain;
            }
            else
            {
                printf( "call to write" );
                exit( 1 );
            }
        }
        n = close( conn_fd );
        if ( n == -1 )
        {
            perror( "call to close" );
            exit( 1 );
        }
    }
}