// server_in.c

#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>

main()
{
    int    i;
    int    fd1, fd2;
    struct sockaddr_in    saddr;
    struct sockaddr_in    caddr;
    int    len;
    int    ret;
    char   buf[1024];

    if ((fd1 = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
	perror("socket");
	exit(1);
    }

    bzero((char *)&saddr, sizeof(saddr));

    saddr.sin_family = AF_INET;
    saddr.sin_addr.s_addr = inet_addr("127.0.0.1");
    saddr.sin_port = htons(9999);

    unlink(SOCK_NAME);
    if (bind(fd1, (struct sockaddr *)&saddr, 
	     sizeof(saddr) ) < 0){
	perror("bind");
	exit(1);
    }
    
    if (listen(fd1, 1) < 0) {
	perror("listen");
	exit(1);
    }

    for(;;) {
	len = sizeof(caddr);
	if ((fd2 = accept(fd1, (struct sockaddr *)&caddr, &len)) < 0) {
	    perror("accept");
	    exit(1);
	}
	close(fd1);
	while (ret = read(fd2, buf, 1024)) {
	    for (i=0; i< ret; i++) {
		if (isalpha(buf[i]))
		    buf[i] = toupper(buf[i]);
	    }
	    write(fd2, buf, 1024);
	}
	close(fd2);
    }
}