Interesting comment. I'm replying with the SE Linux list CC'd so everyone who's involved can comment. Maybe a change to make "\n" equivalent to "" in the SE Linux kernel interfaces in question would be appropriate then? For the SE Linux interfaces in question a '\n' character is not valid in any part of the input and the input must contain three fields separated by colons, so a special case of "\n" being equivalent to "" can not cause any confusion. Also as a side note, in the normal use only libselinux.so has any code which does such zero byte writes. Doing it from bash is only needed for testing, debugging, and educational purposes. On Saturday 26 February 2005 21:39, Miloslav Trmac <mitr@xxxxxxxx> wrote: > On Sat, Feb 26, 2005 at 06:32:13PM +1100, Russell Coker wrote: > > To unset the fscreate or exec context you have to write zero bytes > > to /proc/self/attr/fscreate or /proc/self/attr/exec respectively. > > I personally think this is the problem - no interface should require > writing 0 bytes. > > To quote the POSIX spec: > | Before any action described below is taken, and if nbyte is zero and > | the file is a regular file, the write() function may detect and return > | errors as described below. In the absence of errors, or if error > | detection is not performed, the write() function shall return zero and > | have no other results. If nbyte is zero and the file is not a regular > | file, the results are unspecified. > > Files in /proc _are_ regular files, as far as stat() is concerned, so > I don't think you can require that portable programs give you the > possibility to write 0 bytes to these files. > Mirek -- http://www.coker.com.au/selinux/ My NSA Security Enhanced Linux packages http://www.coker.com.au/bonnie++/ Bonnie++ hard drive benchmark http://www.coker.com.au/postal/ Postal SMTP/POP benchmark http://www.coker.com.au/~russell/ My home page
