Call close(2) after errno is used.

[kjopek_gmail.com]

Summary

close(2) should be called after errno is examined as close may change errno variable.

Test Plan

No functional changes intended.

[kib]

In principle close() might obliterate errno, so rtld_strerror() call in dbg() inside the check becomes corrupted.

[kjopek_gmail.com]

Oh, that means the current (in repo) code is wrong anyway. close(2) should be then called just before return.

[kjopek_gmail.com]

Update patch accordingly to comments.

[kib]

Well, then free() can obliterate errno as well.
I suggest to return to your initial patch, with some modifications.

Note that errno is not set by read(2) unless return value is -1, while code checks both for errors, EOFs, and short reads.
Save the value of errno somewhere if read returned -1, and then use the saved value in dbg().

[kjopek_gmail.com]

Fix similar problems in different locations. Save original errno value from function it originally generated it.

[kjopek_gmail.com]

Actually, we don't need to use errno_copy in first occurence of described problem.

[kib]

Please use diff -U99999999 when generating patch, to add context to the review.

libexec/rtld-elf/libmap.c

106

We call such variable saved_errno in other places.

142

I suggest to issue different dbg() statements for case retval == -1 and retval >= 0. In the first case, use saved_errno, in second report something like 'short read' and print expected and returned lengths.

[kjopek_gmail.com]

Provide different dbg messages for different types of errors.

[kib]

Can you provide 'Submitted by:' line for the commit ?

[kjopek_gmail.com]

Submitted by: Konrad Sewiłło-Jopek