Mercurial > gnulib
changeset 38215:1bb896d10746
dfa: avoid new infinite loop
This would infloop: echo cx | LC_ALL=C grep -E 'c\b[x ]'
* lib/dfa.c (dfastate): When constructing a new state table, we could
initially declare that we had found a match, and later find that
constraints eliminate that possibility, yet continue to use the
now stale "matched" indicator. That would lead to an infinite loop.
The solution is to update "matched" when necessary.
Introduced by commit v0.1-983-g403adf1.
| author | Jim Meyering <meyering@fb.com> |
|---|---|
| date | Tue, 29 Nov 2016 10:45:46 -0800 |
| parents | 98c3a76378d6 |
| children | 06066d898505 |
| files | ChangeLog lib/dfa.c |
| diffstat | 2 files changed, 17 insertions(+), 0 deletions(-) [+] |
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--- a/ChangeLog Mon Nov 28 22:26:07 2016 +0900 +++ b/ChangeLog Tue Nov 29 10:45:46 2016 -0800 @@ -1,3 +1,14 @@ +2016-11-29 Jim Meyering <meyering@fb.com> + + dfa: avoid new infinite loop + This would infloop: echo cx | LC_ALL=C grep -E 'c\b[x ]' + * lib/dfa.c (dfastate): When constructing a new state table, we could + initially declare that we had found a match, and later find that + constraints eliminate that possibility, yet continue to use the + now stale "matched" indicator. That would lead to an infinite loop. + The solution is to update "matched" when necessary. + Introduced by commit v0.1-983-g403adf1. + 2016-11-27 Norihiro Tanaka <noritnk@kcn.ne.jp> dfa: avoid match middle in multibyte character
--- a/lib/dfa.c Mon Nov 28 22:26:07 2016 +0900 +++ b/lib/dfa.c Tue Nov 29 10:45:46 2016 -0800 @@ -2609,6 +2609,12 @@ continue; if (j == CHARCLASS_WORDS) continue; + + /* If we have reset the bit that made us declare "matched", reset + that indicator, too. This is required to avoid an infinite loop + with this command: echo cx | LC_ALL=C grep -E 'c\b[x ]' */ + if (!tstbit (uc, matches)) + matched = false; } #ifdef DEBUG