©2004 by Marc J. Rochkind. All rights reserved. Portions marked "Open Source" may be copied under license.

 

                 

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c8/sktexm.c

Go to the documentation of this file.

/*
    Socket example program (multiple clients)
    AUP2, Sec. 8.01.3

    Copyright 2003 by Marc J. Rochkind. All rights reserved.
    May be copied only for purposes and under conditions described
    on the Web page www.basepath.com/aup/copyright.htm.

    The Example Files are provided "as is," without any warranty;
    without even the implied warranty of merchantability or fitness
    for a particular purpose. The author and his publisher are not
    responsible for any damages, direct or incidental, resulting
    from the use or non-use of these Example Files.

    The Example Files may contain defects, and some contain deliberate
    coding mistakes that were included for educational reasons.
    You are responsible for determining if and how the Example Files
    are to be used.

*/
#include "defs.h"
#include <sys/socket.h>
#include <sys/un.h>
/*[run_server]*/
static bool run_server(struct sockaddr_un *sap)
{
    int fd_skt, fd_client, fd_hwm = 0, fd;
    char buf[100];
    fd_set set, read_set;
    ssize_t nread;

    ec_neg1( fd_skt = socket(AF_UNIX, SOCK_STREAM, 0) )
    ec_neg1( bind(fd_skt, (struct sockaddr *)sap, sizeof(*sap)) )
    ec_neg1( listen(fd_skt, SOMAXCONN) )
    if (fd_skt > fd_hwm)
        fd_hwm = fd_skt;
    FD_ZERO(&set);
    FD_SET(fd_skt, &set);
    while (true) {
        read_set = set;
        ec_neg1( select(fd_hwm + 1, &read_set, NULL, NULL, NULL) )
        for (fd = 0; fd <= fd_hwm; fd++)
            if (FD_ISSET(fd, &read_set)) {
                if (fd == fd_skt) {
                    ec_neg1( fd_client = accept(fd_skt, NULL, 0) )
                    FD_SET(fd_client, &set);
                    if (fd_client > fd_hwm)
                        fd_hwm = fd_client;
                }
                else {
                    ec_neg1( nread = read(fd, buf, sizeof(buf)) )
                    if (nread == 0) {
                        FD_CLR(fd, &set);
                        if (fd == fd_hwm)
                            fd_hwm--;
                        ec_neg1( close(fd) )
                    }
                    else {
                        printf("Server got \"%s\"\n", buf);
                        ec_neg1( write(fd, "Goodbye!", 9 ) )
                    }
                }
            }
    }
    ec_neg1( close(fd_skt) )
    return true;

EC_CLEANUP_BGN
    return false;
EC_CLEANUP_END
}
/*[run_clients]*/
static bool run_client(struct sockaddr_un *sap)
{
    if (fork() == 0) {
        int fd_skt;
        char buf[100];

        ec_neg1( fd_skt = socket(AF_UNIX, SOCK_STREAM, 0) )
        while (connect(fd_skt, (struct sockaddr *)sap, sizeof(*sap)) == -1)
            if (errno == ENOENT) {
                sleep(1);
                continue;
            }
            else
                EC_FAIL
        snprintf(buf, sizeof(buf), "Hello from %ld!",
          (long)getpid());
        ec_neg1( write(fd_skt, buf, strlen(buf) + 1 ) )
        ec_neg1( read(fd_skt, buf, sizeof(buf)) )
        printf("Client got \"%s\"\n", buf);
        ec_neg1( close(fd_skt) )
        exit(EXIT_SUCCESS);
    }
    return true;

EC_CLEANUP_BGN
    /* only child gets here */
    exit(EXIT_FAILURE);
EC_CLEANUP_END
}
/*[main]*/
#define SOCKETNAME "MySocket"

int main(void)
{
    struct sockaddr_un sa;
    int nclient;

    (void)unlink(SOCKETNAME);
    strcpy(sa.sun_path, SOCKETNAME);
    sa.sun_family = AF_UNIX;
    for (nclient = 1; nclient <= 4; nclient++)
        ec_false( run_client(&sa) )
    ec_false( run_server(&sa) )
    exit(EXIT_SUCCESS);

EC_CLEANUP_BGN
        exit(EXIT_FAILURE);
EC_CLEANUP_END
}
/*[]*/

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