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    SubjectRe: RFC: android logger feedback request
    On Wed, 21 Dec 2011 16:36:21 -0800 Tim Bird <> wrote:

    > On 12/21/2011 03:19 PM, Greg KH wrote:
    > > That all describes the current code, but you haven't described what's
    > > wrong with the existing syslog interface that requires this new driver
    > > to be written. And why can't the existing interface be fixed to address
    > > these (potential) shortcomings?
    > >> One specific question I have is where is the most appropriate
    > >> place for this code to live, in the kernel source tree?
    > >> Other embedded systems might want to use this system (it
    > >> is simpler than syslog, and superior in some ways), so I don't
    > >> think it should remain in an android-specific directory.
    > >
    > > What way is it superior?
    > Here are some ways that this code is superior to syslog:

    It is certainly nice and simple. It really looks more like a filesystem than
    a char device though... though they aren't really files so much as lossy
    pipes. I don't think that's a problem though, lots of things in filesystems
    don't behave exactly like files.

    If you created a 'logbuf' filesystem that used libfs to provide a single
    directory in which privileged processes could create files then you wouldn't
    need the kernel to "know" the allowed logs: radio, events, main, system.
    The size could be set by ftruncate() (by privileged used again) rather than
    being hardcoded.

    You would defined 'read' and 'write' much like you currently do to create a list of
    datagrams in a circular buffer and replace the ioctls by more standard

    LOGGER_GET_LOG_BUG_SIZE would use 'stat' and the st_blocks field
    LOGGER_GET_LOG_LEN would use 'stat' and the st_size field
    LOGGER_GET_NEXT_ENTRY_LEN could use the FIONREAD ioctl
    LOGGER_FLUSH_LOG could use ftruncate

    The result would be much the same amount of code, but an interface which has
    fewer details hard-coded and is generally more versatile and accessible.


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