Attachment 4863 Details for Bug 6823 – The test, that shows the problem

The test, that shows the problem

lock_test.c (text/x-csrc), 6.87 KB, created by Pavel Shilovsky on 2009-10-18 00:59:55 UTC

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Creator: Pavel Shilovsky

Created: 2009-10-18 00:59:55 UTC

Size: 6.87 KB

patch

obsolete

>#include <stdio.h>
>
>#include <sys/types.h>
>#include <sys/stat.h>
>#include <fcntl.h>
>#include <errno.h>
>#include <string.h>
>#include <sys/socket.h>
>
>#include <unistd.h>
>
>int main ()
>{
>    char buf[13030];
>    int len, fd, rc, ipc[2], rc2;
>
>    pid_t ppid = getpid();
>
>    printf("start %d\n", getpid());
>
>    if (socketpair(PF_UNIX, SOCK_DGRAM, 0, ipc) < 0) {
>        fprintf(stderr, "socketpair failed\n");
>        return 1;
>    }
>
>    rc = fork();
>    if (rc < 0) {
>        fprintf(stderr, "fork failed\n");
>        return 1;
>    }
>
>    if (rc == 0) {
>        int fdsrv, fdsrv2;
>        struct flock flk;
>
>        char control[sizeof(struct cmsghdr)+10];
>        struct msghdr msg;
>        struct cmsghdr *cmsg;
>        struct iovec iov;
>        int *fdmsg;
>
>        setsid();
>        printf("server start %d\n", getpid());
>
>        fdsrv = open("PDOXUSRS.NET", O_RDWR);
>        if (fd < 0) {
>            fprintf(stderr, "open failed\n");
>            return 1;
>        }
>        printf("server open for %d\n", fdsrv);
>
>        fdsrv2 = open("PDOXUSRS.NET", O_RDWR);
>        if (fd < 0) {
>            fprintf(stderr, "second open failed\n");
>            return 1;
>        }
>        printf("server second open for %d\n", fdsrv2);
>
>        flk.l_type = F_WRLCK;
>        flk.l_whence = SEEK_SET;
>        flk.l_start = 0;
>        flk.l_len = 1;
>        //flk.l_pid = ppid;
>
>        if (fcntl(fdsrv, F_SETLK, &flk) < 0)
>            fprintf(stderr, "fcntl set lock on %d failed (%s)\n", fdsrv, strerror(errno));
>
>        memset(&flk, 0, sizeof(flk));
>        flk.l_type = F_WRLCK;
>        flk.l_whence = SEEK_SET;
>        flk.l_start = 1;
>        flk.l_len = 2;
>        //flk.l_pid = ppid;
>
>        if (fcntl(fdsrv2, F_SETLK, &flk) < 0)
>            fprintf(stderr, "fcntl set lock on %d failed (%s)\n", fdsrv2, strerror(errno));
>
>        if (close(fdsrv2) < 0)
>            fprintf(stderr, "close failed %d (%s)\n", fdsrv2, strerror(errno));
>        else
>            printf("server close %d\n", fdsrv2);
>
>        /* Response data */
>        iov.iov_base = "OK";
>        iov.iov_len  = 2;
>
>        /* compose the message */
>        memset(&msg, 0, sizeof(msg));
>        msg.msg_iov = &iov;
>        msg.msg_iovlen = 1;
>        msg.msg_control = control;
>        msg.msg_controllen = sizeof(control);
>
>        /* attach open fdsrv */
>        cmsg = CMSG_FIRSTHDR(&msg);
>        cmsg->cmsg_level = SOL_SOCKET;
>        cmsg->cmsg_type = SCM_RIGHTS;
>        cmsg->cmsg_len = CMSG_LEN(sizeof(fdsrv));
>        fdmsg = (int *)CMSG_DATA(cmsg);
>        fdmsg[0] = fdsrv;
>
>        msg.msg_controllen = cmsg->cmsg_len;
>
>        if (sendmsg(ipc[1], &msg, 0) < 0)
>                fprintf(stderr,"sendmsg failed\n");
>
>        printf("server send %d\n", fdsrv);
>
>        memset(&flk, 0, sizeof(flk));
>        flk.l_type = F_WRLCK;
>        flk.l_whence = SEEK_SET;
>        flk.l_start = 0;
>        flk.l_len = 1;
>
>        if (fcntl(fd, F_GETLK, &flk) < 0)
>            fprintf(stderr, "server fcntl get lock failed (%s)\n", strerror(errno));
>
>
>        if (flk.l_type != F_UNLCK)
>            printf("server file locked by %d\n",flk.l_pid);
>        else
>            printf("server file not locked\n");
>
>        sleep(5);
>
>        printf("server end\n");
>
>        close(fd);
>
>        return 0;
>    }
>
>    rc2 = fork();
>    if (rc2 < 0) {
>        fprintf(stderr, "second fork failed\n");
>        return 1;
>    }
>
>    if (rc2 == 0) {
>        int fdx, lenx;
>        struct flock flkx;
>
>        setsid();
>        printf("second server start %d\n", getpid());
>        sleep(1);
>
>        fdx = open("PDOXUSRS.NET", O_RDWR);
>        if (fdx < 0) {
>            fprintf(stderr, "second open failed\n");
>            return 1;
>        }
>        printf("second server open for %d\n", fdx);
>
>        flkx.l_type = F_WRLCK;
>        flkx.l_whence = SEEK_SET;
>        flkx.l_start = 10;
>        flkx.l_len = 2;
>        //flk.l_pid = ppid;
>
>        if (fcntl(fdx, F_SETLK, &flkx) < 0)
>            fprintf(stderr, "second server fcntl set lock on %d failed (%s)\n", fdx, strerror(errno));
>        else
>            printf("second server lock for %d\n", fdx);
>
>        sleep(1);
>
>        if ((rc = lseek(fdx, 10, SEEK_SET)) < 0)
>            fprintf(stderr, "second server lseek failed on %d (%s)\n", fdx, strerror(errno));
>        else
>            printf("second server lseek done on %d with %d\n", fdx, rc);
>
>        if ((lenx = read(fdx, buf, 2)) < 0)
>            fprintf(stderr, "second server read failed on %d (%s)\n", fdx, strerror(errno));
>        else
>            printf("second server read done on %d with %d\n", fdx, lenx);
>
>
>        printf("wait second server for end\n");
>
>        sleep(9);
>
>        printf("second server end\n");
>
>        close(fdx);
>
>        return 0;
>    }
>
>    char  control[1024];
>    struct msghdr msg;
>    struct cmsghdr *cmsg;
>    struct iovec iov;
>    int result;
>
>    struct flock flk;
>
>    memset(&msg, 0, sizeof(msg));
>    iov.iov_base = buf;
>    iov.iov_len = 1024;
>    msg.msg_iov = &iov;
>    msg.msg_iovlen = 1;
>    msg.msg_control = control;
>    msg.msg_controllen = sizeof(control);
>
>    if (recvmsg(ipc[0], &msg, 0) < 0) {
>        fprintf(stderr, "recvmsg failed (%s)\n", strerror(errno));
>        return -1;
>    }
>
>    fd = -1;
>    cmsg = CMSG_FIRSTHDR(&msg);
>    while (cmsg != NULL) {
>            if (cmsg->cmsg_level == SOL_SOCKET
>             && cmsg->cmsg_type  == SCM_RIGHTS) {
>                    fd = *(int *) CMSG_DATA(cmsg);
>                    printf ("fd received=%d (len=%d)\n", fd,
>                            (cmsg->cmsg_len - CMSG_LEN(0))/sizeof(int));
>            }
>            cmsg = CMSG_NXTHDR(&msg, cmsg);
>    }
>
>    sleep(2);
>
>    flk.l_type = F_WRLCK;
>    flk.l_whence = SEEK_SET;
>    flk.l_start = 1;
>    flk.l_len = 2;
>
>    if (fcntl(fd, F_GETLK, &flk) < 0)
>        fprintf(stderr, "fcntl get lock on %d failed (%s)\n", fd, strerror(errno));
>
>    if (flk.l_type != F_UNLCK)
>        printf("file %d locked by %d\n", fd, flk.l_pid);
>    else
>        printf("file %d not locked\n", fd);
>
>    if ((len = read(fd, buf, 1)) < 0)
>        fprintf(stderr, "first read failed on %d (%s)\n", fd, strerror(errno));
>    else
>        printf("first read done on %d with %d\n", fd, len);
>
>    if ((rc = lseek(fd, 1, SEEK_SET)) < 0)
>        fprintf(stderr, "second lseek failed on %d (%s)\n", fd, strerror(errno));
>    else
>        printf("second lseek done on %d with %d\n", fd, rc);
>
>    if ((len = read(fd, buf, 2)) < 0)
>        fprintf(stderr, "second read failed on %d (%s)\n", fd, strerror(errno));
>    else
>        printf("second read done on %d with %d\n", fd, len);
>
>    if ((rc = lseek(fd, 10, SEEK_SET)) < 0)
>        fprintf(stderr, "third lseek failed on %d (%s)\n", fd, strerror(errno));
>    else
>        printf("third lseek done on %d with %d\n", fd, rc);
>
>    if ((len = read(fd, buf, 2)) < 0)
>        fprintf(stderr, "third read failed on %d (%s)\n", fd, strerror(errno));
>    else {
>        buf[len] = '\0';
>        printf("third read done on %d with %d\ndata:%s\n", fd, len, buf);
>    }
>
>    printf("done\n");
>}

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Attachments on bug 6823: 4863