82 lines
3.0 KiB
Diff
82 lines
3.0 KiB
Diff
From 9618fb718b75920f37e5be2049ad1d0bb5c4a28c Mon Sep 17 00:00:00 2001
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From: Paul Eggert <eggert@cs.ucla.edu>
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Date: Tue, 26 Jan 2021 09:23:54 -0800
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Subject: [PATCH] expr: fix bug with unmatched \(...\)
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Problem reported by Qiuhao Li.
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* doc/coreutils.texi (String expressions):
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Document the correct behavior, which POSIX requires.
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* src/expr.c (docolon): Treat unmatched \(...\) as empty.
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* tests/misc/expr.pl: New test.
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Upstream-commit: 735083ba24878075235007b4417982ad5700436d
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Signed-off-by: Kamil Dudka <kdudka@redhat.com>
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---
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doc/coreutils.texi | 14 ++++++++------
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src/expr.c | 9 +++++++--
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tests/misc/expr.pl | 3 +++
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3 files changed, 18 insertions(+), 8 deletions(-)
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diff --git a/doc/coreutils.texi b/doc/coreutils.texi
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index 2382a16..5b2bb2c 100644
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--- a/doc/coreutils.texi
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+++ b/doc/coreutils.texi
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@@ -13529,12 +13529,14 @@ second is considered to be a (basic, a la GNU @code{grep}) regular
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expression, with a @code{^} implicitly prepended. The first argument is
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then matched against this regular expression.
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-If the match succeeds and @var{regex} uses @samp{\(} and @samp{\)}, the
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-@code{:} expression returns the part of @var{string} that matched the
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-subexpression; otherwise, it returns the number of characters matched.
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-
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-If the match fails, the @code{:} operator returns the null string if
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-@samp{\(} and @samp{\)} are used in @var{regex}, otherwise 0.
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+If @var{regex} does not use @samp{\(} and @samp{\)}, the @code{:}
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+expression returns the number of characters matched, or 0 if the match
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+fails.
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+
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+If @var{regex} uses @samp{\(} and @samp{\)}, the @code{:} expression
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+returns the part of @var{string} that matched the subexpression, or
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+the null string if the match failed or the subexpression did not
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+contribute to the match.
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@kindex \( @r{regexp operator}
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Only the first @samp{\( @dots{} \)} pair is relevant to the return
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diff --git a/src/expr.c b/src/expr.c
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index e134872..0616a42 100644
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--- a/src/expr.c
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+++ b/src/expr.c
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@@ -721,8 +721,13 @@ docolon (VALUE *sv, VALUE *pv)
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/* Were \(...\) used? */
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if (re_buffer.re_nsub > 0)
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{
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- sv->u.s[re_regs.end[1]] = '\0';
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- v = str_value (sv->u.s + re_regs.start[1]);
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+ if (re_regs.end[1] < 0)
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+ v = str_value ("");
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+ else
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+ {
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+ sv->u.s[re_regs.end[1]] = '\0';
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+ v = str_value (sv->u.s + re_regs.start[1]);
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+ }
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}
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else
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{
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diff --git a/tests/misc/expr.pl b/tests/misc/expr.pl
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index e45f8e7..e57f79d 100755
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--- a/tests/misc/expr.pl
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+++ b/tests/misc/expr.pl
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@@ -84,6 +84,9 @@ my @Tests =
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# In 5.94 and earlier, anchors incorrectly matched newlines.
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['anchor', "'a\nb' : 'a\$'", {OUT => '0'}, {EXIT => 1}],
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+ # In 8.32, \( ... \) that did not match caused memory errors.
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+ ['emptysub', '"a" : "\\(b\\)*"', {OUT => ''}, {EXIT => 1}],
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+
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# These tests are taken from grep/tests/bre.tests.
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['bre1', '"abc" : "a\\(b\\)c"', {OUT => 'b'}],
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['bre2', '"a(" : "a("', {OUT => '2'}],
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--
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2.26.2
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