p12-22.c

SUN Solaris8平台下进程间通信

#include <unistd.h>
#include <sys/socket.h>
#include <stdio.h>
#include "err_exit.h"
struct buffer{
    char *buffer;              /* 存放数据的缓冲区 */
    int size;                  /* 数据大小 */
    struct buffer *next;       /* 下一块数据缓冲区指针 */
};
struct buffer* read_oob (int socket) 
{
    struct buffer *tail = NULL;
    struct buffer *list = NULL;
     
    while (1) {
        char *buff = (char *) xmalloc(1024); 
        struct buffer *link;
        int success;
        int result;
        /* 尝试读带外数据 */
        success = recv(socket, buff, sizeof(buff), MSG_OOB);
        if (success >= 0) {
            /* 已成功读到，将它返回 */
            struct buffer *link
                 = (struct buffer *) xmalloc (sizeof (struct buffer));
            link->buffer = buff;
            link->size = success;
            link->next = list;
            return link;
        }
        if (errno != EAGAIN) 
            err_exit("recv error"); 
        /* 若失败且为EAGAIN错误，查看是否位于带外数据标志处 */
        success = sockatmark(socket);
        if (success < 0)
            printf ("sockatmark error\n");
        if (success) {  /* 位于标志处，无需再读普通数据，等待一会儿 */
            sleep (1);
            continue;
        }
        /* 否则，读普通数据并保存它。如果普通数据在该标志之前，这保证不会读过标志*/
        success = read (socket, buff, sizeof(buff));
        if (success < 0)
             perror ("read");
        /* 保存这块数据至缓冲区链表 */
        {
           struct buffer *link
                = (struct buffer *)xmalloc(sizeof(struct buffer));
            link->buffer = buff;
            link->size = success;
            /* 加至链尾 */
            if (tail)
               tail->next = link;
            else
               list = link;
            tail = link;
        }
    }
}