Fix memory leaks during "tail -r" of a non-regular file
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Authored by asomers on Jan 6 2017, 6:00 PM.

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ngie

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Summary

Fix memory leaks during "tail -r" of a non-regular file

Rewrite r_buf to use standard tail queues instead of a hand-rolled circular linked list. Free dynamic allocations when done.
Remove an optimization for the case where the file is a multiple of 128KB in size and there is a scarcity of memory.
Add ATF tests for "tail -r" and its variants.

Test Plan

Added ATF tests

Repository

rS FreeBSD src repository - subversion

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Tests Not Applicable

asomers retitled this revision from to Fix memory leaks during "tail -r" of a non-regular file.

asomers updated this object.

asomers edited the test plan for this revision. (Show Details)

asomers added a reviewer: ngie.

usr.bin/tail/reverse.c
193 ↗	(On Diff #23660)	Might be a good idea to initialize this to NULL to ensure someone doesn't add a goto that will free a bogus memory allocation.
193 ↗	(On Diff #23660)	this -> `first`.
201 ↗	(On Diff #23660)	Whitespace is off here.
207–213 ↗	(On Diff #23660)	This whitespace looks off.
219 ↗	(On Diff #23660)	Whitespace looks off here.
246 ↗	(On Diff #23660)	`while (tl != NULL) {`
248 ↗	(On Diff #23660)	Should this be readded (well.. an adapted version), just in case?
260 ↗	(On Diff #23660)	`if (tr != NULL) {`?
usr.bin/tail/tests/tail_test.sh
118 ↗	(On Diff #23660)	`tail -r < infile > outpipe` instead?
134 ↗	(On Diff #23660)	Should check the result of this command to make sure this succeeds.
143–144 ↗	(On Diff #23660)	Probably should check diskspace beforehand to make sure there's enough, right?
163 ↗	(On Diff #23660)	`tail -r < infile > outpipe` instead?
179 ↗	(On Diff #23660)	Same here with using `cat`...
195 ↗	(On Diff #23660)	Why `/bin/echo` ?

usr.bin/tail/reverse.c
248 ↗	(On Diff #23660)	I'm not sure how. fread can't return EOF. You must use feof(3) instead, which is what I do.
usr.bin/tail/tests/tail_test.sh
134 ↗	(On Diff #23660)	good catch
195 ↗	(On Diff #23660)	Reflexes. Earlier versions of bash didn't implement "-n" in the echo builtin. But it looks like our sh has no such problem.