Re: [Libguestfs] [libnbd PATCH v3 10/29] lib/utils: add unit tests for async-signal-safe execvpe()
On 2/16/23 00:33, Eric Blake wrote:
On Wed, Feb 15, 2023 at 05:03:48PM -0600, Eric Blake wrote:
>> +
>> +# Create subdirectories for triggering non-fatal internal error conditions of
>> +# execvpe(). (Almost) every subdirectory will contain one entry, called
"f".
>> +#
>> +# Create a directory that's empty.
>> +mkdir empty
>> +
>> +# Create a directory with a named pipe (FIFO) in it.
>> +mkdir fifo
>> +mkfifo fifo/f
>> +
>> +# Create a directory with a non-executable file in it.
>> +mkdir nxregf
>> +touch nxregf/f
>> +
>> +# Create a symlink loop.
>> +ln -s symlink symlink
Another interesting thing you might want to add to the test:
mkdir -p subdir/f
then show that PATH=...:subdir:... does not get tripped up by
subdir/f/ having the execute bit set (aka search bit since it's a
directory) but not being an executable.
Hmm. There could be two spots to test this (because what we're
triggering here is EACCES). One, *between* the following two tests:
run "" fifo/f; execve_fail fifo/f EACCES
run "" nxregf/f; execve_fail nxregf/f EACCES
because "fifo/f" is effectively the same test as "subdir/f" -- not a
regular file in the first place.
Two, inside:
run empty:fifo:nxregf:symlink f
execve_fail empty/f,fifo/f,nxregf/f,symlink/f ELOOP
(again inserted between the fifo and the nxregf cases).
Now, while developing the test cases, I did (somewhat unwittingly) end
up testing what you propose, but then I decided that trying to execute a
directory was not much different from trying to execute a fifo -- the x
file mode bit shouldn't matter because the file type wouldn't be right
in the first place (the x bit should only matter on regular files).
So... Do you think "subdir/f" improves code coverage? If so, do you
agree that I should extend one (or both!) of the above two tests -- or
else, should I add something entirely new?
Thanks!
Laszlo