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Differential D45217

libdiff: Detect and recover from file truncation.
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Authored by des on May 16 2024, 12:26 PM.
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markj

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thj
kevans
markj
Group Reviewers
Klara
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rG974ea6b297f8: libdiff: Detect and recover from file truncation.
Summary

If a memory-mapped file is truncated before we get to the end, the
atomizer may catch SIGBUS. Detect that, reduce the input length to
what we were actually able to read, and set a flag so the caller can
take further action (e.g. warn the user and / or start over).

Sponsored by: Klara, Inc.

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rG FreeBSD src repository
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Tests Not Applicable

Event Timeline

des created this revision.May 16 2024, 12:26 PM
Herald added a subscriber: imp. · View Herald TranscriptMay 16 2024, 12:26 PM
des requested review of this revision.May 16 2024, 12:26 PM
Harbormaster completed remote builds in B57726: Diff 138610.May 16 2024, 12:26 PM
des added a child revision: D45218: libdiff: Add a test for the truncation issue..May 16 2024, 12:26 PM
allanjude added a reviewer: kevans.May 16 2024, 1:38 PM
markj added a subscriber: markj.Fri, May 17, 2:08 PM
markj added inline comments.
contrib/libdiff/lib/diff_atomize_text.c
190–191

Why exactly is this change needed? I can't see the problem with continuing to use pos.

des marked an inline comment as done.Fri, May 17, 5:27 PM
des added inline comments.
contrib/libdiff/lib/diff_atomize_text.c
190–191

pos is volatile, line_start can be cached / optimized.

markj added inline comments.Fri, May 17, 5:28 PM
contrib/libdiff/lib/diff_atomize_text.c
190–191

But then why do we still have .at = pos?

des marked an inline comment as done.Fri, May 17, 8:45 PM
des added inline comments.
contrib/libdiff/lib/diff_atomize_text.c
190–191

Because I didn't spot it...

des updated this revision to Diff 138700.Fri, May 17, 8:59 PM

line_start

Harbormaster completed remote builds in B57743: Diff 138700.Fri, May 17, 8:59 PM
des marked an inline comment as done.Fri, May 17, 9:00 PM
markj accepted this revision as: markj.Mon, May 20, 1:20 PM
This revision is now accepted and ready to land.Mon, May 20, 1:20 PM
Closed by commit rG974ea6b297f8: libdiff: Detect and recover from file truncation. (authored by des). · Explain WhyMon, May 20, 1:33 PM
This revision was automatically updated to reflect the committed changes.
des added a commit: rG974ea6b297f8: libdiff: Detect and recover from file truncation..

Revision Contents
Changeset List

PathSize
contrib/
libdiff/
include/
1 line
lib/
35 lines

Diff 138777

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contrib/libdiff/include/diff_main.h

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contrib/libdiff/lib/diff_atomize_text.c

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