lkml.org 
[lkml]   [2005]   [Mar]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: lseek on /proc/kmsg
    On Wed, 23 Mar 2005, Jan Engelhardt wrote:

    >
    > 1> Sure, read() needs to be modified to respect the file-position
    > 1> set by kmsg_seek(). I don't think you can get away with the
    > 1> call back into do_syslog.
    >
    > 2>I'm not sure that seek makes any sense on that, since it is more like a
    > 2>pipe than a normal file..
    >
    > Well, seek(fd, 0, SEEK_END) could be used to flush a pipe's buffers.
    >

    Yep. That's what I tried to do. Just returns 0 and continues to
    contain all the cached data.


    > 0>> +static loff_t kmsg_seek(struct file *filp, loff_t offset, int origin) {
    > 0>> + if(origin != 2 /* SEEK_END */ || offset < 0) { return -ESPIPE; }
    > 3> "Allow" seeking past the end of the buffer?
    >
    > Well, what does lseek(fd, >0, SEEK_END) do on normal files?
    >

    Goes to the end plus offset. A subsequent read returns EOF
    or 0 depending upon your read mechanism. This is what I wanted
    to do but with no offset.

    Currently, I do this crap:

    for(;;)
    {
    pfd.fd = ifd;
    pfd.events = POLLIN;
    pfd.revents = 0;
    if(poll(&pfd, 1, 0) <= 0)
    break;
    (void)read(ifd, ibuf, BUF_LEN);
    }

    I should be able to just lseek(ifd, 0 SEEK_END);

    > --
    >

    Cheers,
    Dick Johnson
    Penguin : Linux version 2.6.11 on an i686 machine (5537.79 BogoMips).
    Notice : All mail here is now cached for review by Dictator Bush.
    98.36% of all statistics are fiction.
    -
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/

    \
     
     \ /
      Last update: 2005-04-06 13:30    [W:0.020 / U:60.444 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site