Re: [9fans] `test -x` returns wrong results for directories

[ori@eigenstate.org]

> it's open() which is failing. i suppose it should.
> 
> if the open fails, maybe access should stat the file, and if it's a
> directory, try dirread(2). or maybe just opening it for reading will
> work. i don't know, i'm new to this bit of plan 9 & i haven't slept.

This is a bit subtle, though -- if you want
to check if *you* can traverse the directory,
then simply checking for an execute bit isn't
enough -- you need to check that you belong to
a group that has the execute bit.

On a related note, execute permission seems
to behave strangely in general. You can create
a directory and list it:


Even without execute permission it's listable.
Makes sense.

	cpu% mkdir -p d/a/b
	cpu% touch d/x
	cpu% chmod -x d
	cpu% ls -ld d
	d-rw-r--r-- M 81 ori ori 0 Jun  5 07:53 d
	cpu% ls d
	d/a
	d/x

As expected, it can't be traversed:

	cpu% ls d/x
	ls: d/x: 'd/x' does not exist

But, you can cd into it:

	cpu% cd d

And list '.':

	cpu% ls
	a
	x
	cpu% ls .
	a
	x

Can't traverse it to list subdirectories,
though:

	ls a
	ls: a: 'a' access permission denied
	cd a
	Can't cd a: 'a' access permission denied
	cpu% cd ..
	Can't cd ..: '..' access permission denied

So, cd'ing into a directory withut +x leads
to an inescapabler trap.

Perhaps 'cd' should prevent entering that
directory.