Attachment 144963 Details for Bug 192109 – sample program to reproduce problem

sample program to reproduce problem

example.c (text/plain), 2.43 KB, created by Abhijit on 2014-07-25 10:54:09 UTC

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Creator: Abhijit

Created: 2014-07-25 10:54:09 UTC

Size: 2.43 KB

patch

obsolete

>#include <sys/types.h>
>#include <sys/socket.h>
>#include <sys/uio.h>
>#include <stdio.h>
>
>main()
>{
>    int pair[2];
>    struct msghdr mh;
>    struct cmsghdr cmh[2];
>    struct iovec iov;
>    char tbuf[100];
>    int fd;
>    int rlen;
>    pid_t pid;
>    char buffer[1024];
>
>    if ( socketpair(AF_UNIX, SOCK_STREAM, 0, pair) < 0 ) {
>        perror("socketpair");
>        exit(1);
>    }
>
>    fflush(stdout);
>    fflush(stderr);
>
>    switch ( pid = fork() ) {
>
>    case 0:             /* Child sends the file descriptor */
>        fd = open("/etc/motd",0);
>        if ( fd < 0 ) {
>            perror("open");
>            exit(0);
>        }
>        memset(&mh,0,sizeof(mh));
>        mh.msg_name = 0;
>        mh.msg_namelen = 0;
>        mh.msg_iov = &iov;
>        mh.msg_iovlen = 1;
>        mh.msg_control = (caddr_t)&cmh[0];
>        mh.msg_controllen = sizeof(cmh[0]) + sizeof(int);
>        mh.msg_flags = 0;
>        iov.iov_base = "hello";
>        iov.iov_len = strlen(iov.iov_base) + 1;
>        cmh[0].cmsg_level = SOL_SOCKET;
>        cmh[0].cmsg_type = SCM_RIGHTS;
>        cmh[0].cmsg_len = sizeof(cmh[0]) + sizeof(int);
>        *(int *)&cmh[1] = fd;
>        if ( sendmsg(pair[1],&mh,0) < 0 ) {
>            perror("sendmsg");
>            exit(1);
>        }
>        close(fd);
>        printf("child done\n");
>        fflush(stdout);
>        exit(0);
>
>    case -1:            /* Oops! */
>        perror("fork");
>        exit(1);
>
>    default:            /* Parent receives the file descriptor */
>        mh.msg_name = 0;
>        mh.msg_namelen = 0;
>        mh.msg_iov = &iov;
>        mh.msg_iovlen = 1;
>        mh.msg_control = (caddr_t)&cmh[0];
>        mh.msg_controllen = sizeof(cmh[0]) * 2;
>        iov.iov_base = tbuf;
>        iov.iov_len = sizeof(tbuf);
>        cmh[0].cmsg_len = sizeof(cmh[0]) + sizeof(int);
>        if ( (rlen = recvmsg(pair[0],&mh,0)) < 0 ) {
>            perror("recvmsg");
>            exit(1);
>        }
>        fd = *(int *)&cmh[1];
>        printf("rlen = %d msg_controllen = %d, cmsg_len = %d\n",
>            rlen,mh.msg_controllen,cmh[0].cmsg_len);
>        printf("cmsg_level = %d, cmsg_type = %d, fd = %d\n",
>            cmh[0].cmsg_level,cmh[0].cmsg_type,fd);
>        while ( (rlen = read(fd,buffer,sizeof(buffer))) > 0 ) {
>            write(1,buffer,rlen);
>        }
>        if ( rlen < 0 ) {
>            perror("read");
>            exit(1);
>        }
>        exit(0);
>    }
>}

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