Messages in this thread | | | Subject | Re: Does anyone care about a race free ptsname? | From | "H. Peter Anvin" <> | Date | Tue, 19 Apr 2016 13:55:09 -0700 |
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On 04/19/2016 01:32 PM, Eric W. Biederman wrote: > > The challenge came in operations such as granpt. Where you are passed > in a ptmx file descriptor from who knows where, and you pass it on > to applications such as pt_chown which run with elevatated privileged. > > As the information is available of where devpts is mounted in > relationship to /dev/ptmx I have no more concerns about implementing > ptsname. Path pased is also sufficiently backwards compatible it would > not usually be wrong even on existing kernels. >
pt_chown is evil. It should have been removed ages ago, and from the very beginning have failed if run on a devpts filesystem. Unfortunately the glibc people didn't do so, and that is a major reason we're in the current mess.
That being said, the ioctl(TIOCOPENSLAVE) idea would deal with that.
-hpa
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