C-exp-collection/server-exp4/common.c

/* $begin common.c */
#include "common.h"

/*********************************************************************
 * The Rio package - robust I/O functions
 **********************************************************************/

ssize_t rio_readn(int fd, void *usrbuf, size_t n)
{
    size_t nleft = n;
    ssize_t nread;
    char *bufp = usrbuf;

    while (nleft > 0) {
        if ((nread = read(fd, bufp, nleft)) < 0) {
            if (errno == EINTR)
                nread = 0;
            else
                return -1;
        }
        else if (nread == 0)
            break;
        nleft -= nread;
        bufp += nread;
    }
    return (n - nleft);
}

ssize_t rio_writen(int fd, void *usrbuf, size_t n)
{
    size_t nleft = n;
    ssize_t nwritten;
    char *bufp = usrbuf;

    while (nleft > 0) {
        if ((nwritten = write(fd, bufp, nleft)) <= 0) {
            if (errno == EINTR)
                nwritten = 0;
            else
                return -1;
        }
        nleft -= nwritten;
        bufp += nwritten;
    }
    return n;
}

static ssize_t rio_read(rio_t *rp, char *usrbuf, size_t n)
{
    int cnt;
    while (rp->rio_cnt <= 0) {
        rp->rio_cnt = read(rp->rio_fd, rp->rio_buf,
                   sizeof(rp->rio_buf));
        if (rp->rio_cnt < 0) {
            if (errno != EINTR)
                return -1;
        }
        else if (rp->rio_cnt == 0)
            return 0;
        else
            rp->rio_bufptr = rp->rio_buf;
    }
    cnt = n;
    if (rp->rio_cnt < n)
        cnt = rp->rio_cnt;
    memcpy(usrbuf, rp->rio_bufptr, cnt);
    rp->rio_bufptr += cnt;
    rp->rio_cnt -= cnt;
    return cnt;
}

void rio_readinitb(rio_t *rp, int fd)
{
    rp->rio_fd = fd;
    rp->rio_cnt = 0;
    rp->rio_bufptr = rp->rio_buf;
}

ssize_t rio_readnb(rio_t *rp, void *usrbuf, size_t n)
{
    size_t nleft = n;
    ssize_t nread;
    char *bufp = usrbuf;

    while (nleft > 0) {
        if ((nread = rio_read(rp, bufp, nleft)) < 0) {
            if (errno == EINTR)
                nread = 0;
            else
                return -1;
        }
        else if (nread == 0)
            break;
        nleft -= nread;
        bufp += nread;
    }
    return (n - nleft);
}

ssize_t rio_readlineb(rio_t *rp, void *usrbuf, size_t maxlen)
{
    int n, rc;
    char c, *bufp = usrbuf;

    for (n = 1; n < maxlen; n++) {
        if ((rc = rio_read(rp, &c, 1)) == 1) {
            *bufp++ = c;
            if (c == '\n')
                break;
        } else if (rc == 0) {
            if (n == 1)
                return 0;
            else
                break;
        } else
            return -1;
    }
    *bufp = 0;
    return n;
}

/********************************
 * Client/server helper functions
 ********************************/

int open_client_sock(char *hostname, int port)
{
    int client_sock;
    struct hostent *hp;
    struct sockaddr_in serveraddr;

    if ((client_sock = socket(AF_INET, SOCK_STREAM, 0)) < 0)
        return -1;

    if ((hp = gethostbyname(hostname)) == NULL)
        return -2;
    bzero((char *) &serveraddr, sizeof(serveraddr));
    serveraddr.sin_family = AF_INET;
    bcopy((char *)hp->h_addr_list[0],
          (char *)&serveraddr.sin_addr.s_addr, hp->h_length);
    serveraddr.sin_port = htons(port);

    if (connect(client_sock, (SA *) &serveraddr, sizeof(serveraddr)) < 0)
        return -1;
    return client_sock;
}

int open_listen_sock(int port)
{
    int listen_sock, optval=1;
    struct sockaddr_in serveraddr;

    if ((listen_sock = socket(AF_INET, SOCK_STREAM, 0)) < 0)
        return -1;

    if (setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR,
               (const void *)&optval , sizeof(int)) < 0)
        return -1;

    bzero((char *) &serveraddr, sizeof(serveraddr));
    serveraddr.sin_family = AF_INET;
    serveraddr.sin_addr.s_addr = htonl(INADDR_ANY);
    serveraddr.sin_port = htons((unsigned short)port);
    if (bind(listen_sock, (SA *)&serveraddr, sizeof(serveraddr)) < 0)
        return -1;

    if (listen(listen_sock, LISTENQ) < 0)
        return -1;
    return listen_sock;
}