Re: RFC: android logger feedback request

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]


On Wed, 21 Dec 2011 16:36:21 -0800 Tim Bird <tim.bird@xxxxxxxxxxx> 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_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.


Attachment: signature.asc
Description: PGP signature

[Index of Archives]     [Gstreamer Embedded]     [Linux MMC Devel]     [U-Boot V2]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux ARM Kernel]     [Linux OMAP]     [Linux SCSI]

  Powered by Linux