vampyre...@gmail.com wrote:
grep 2.21 incorrectly handles a -P regular expression that 2.20 handled
correctly.
Thanks for reporting that. I installed the attached patches. The first fixes
the bug; the second is a minor cleanup.
>From bffb51cfda75eeb1d99c34973d5a45fc1b784d89 Mon Sep 17 00:00:00 2001
From: Paul Eggert <egg...@cs.ucla.edu>
Date: Fri, 3 Jul 2015 08:10:54 -0700
Subject: [PATCH 1/2] grep: don't mishandle left context in -P
http://bugs.gnu.org/20957
* src/pcresearch.c (jit_exec): New arg SEARCH_OFFSET.
Caller changed.
(Pexecute): Pass the left context to pcre_exec, so that PCRE
regular-expression matching can see it.
* tests/pcre-context: New file, to test for this bug.
* tests/Makefile.am (TESTS): Add it.
---
src/pcresearch.c | 55 +++++++++++++++++++++++++++++++++---------------------
tests/Makefile.am | 1 +
tests/pcre-context | 38 +++++++++++++++++++++++++++++++++++++
3 files changed, 73 insertions(+), 21 deletions(-)
create mode 100755 tests/pcre-context
diff --git a/src/pcresearch.c b/src/pcresearch.c
index aa05e20..b1f8310 100644
--- a/src/pcresearch.c
+++ b/src/pcresearch.c
@@ -43,16 +43,18 @@ static pcre_extra *extra;
static int jit_stack_size;
# endif
-/* Match the already-compiled PCRE pattern against the data in P, of
- size SEARCH_BYTES, with options OPTIONS, and storing resulting
- matches into SUB. Return the (nonnegative) match location or a
- (negative) error number. */
+/* Match the already-compiled PCRE pattern against the data in SUBJECT,
+ of size SEARCH_BYTES and starting with offset SEARCH_OFFSET, with
+ options OPTIONS, and storing resulting matches into SUB. Return
+ the (nonnegative) match location or a (negative) error number. */
static int
-jit_exec (char const *p, int search_bytes, int options, int *sub)
+jit_exec (char const *subject, int search_bytes, int search_offset,
+ int options, int *sub)
{
while (true)
{
- int e = pcre_exec (cre, extra, p, search_bytes, 0, options, sub, NSUB);
+ int e = pcre_exec (cre, extra, subject, search_bytes, search_offset,
+ options, sub, NSUB);
# if PCRE_STUDY_JIT_COMPILE
if (e == PCRE_ERROR_JIT_STACKLIMIT
@@ -187,6 +189,11 @@ Pexecute (char const *buf, size_t size, size_t *match_size,
int e = PCRE_ERROR_NOMATCH;
char const *line_end;
+ /* The search address to pass to pcre_exec. This is the start of
+ the buffer, or just past the most-recently discovered encoding
+ error. */
+ char const *subject = buf;
+
/* If the input type is unknown, the caller is still testing the
input, which means the current buffer cannot contain encoding
errors and a multiline search is typically more efficient.
@@ -226,12 +233,13 @@ Pexecute (char const *buf, size_t size, size_t *match_size,
bol = false;
}
+ int search_offset = p - subject;
+
/* Check for an empty match; this is faster than letting
pcre_exec do it. */
- int search_bytes = line_end - p;
- if (search_bytes == 0)
+ if (p == line_end)
{
- sub[0] = sub[1] = 0;
+ sub[0] = sub[1] = search_offset;
e = empty_match[bol];
break;
}
@@ -242,17 +250,18 @@ Pexecute (char const *buf, size_t size, size_t *match_size,
if (multiline)
options |= PCRE_NO_UTF8_CHECK;
- e = jit_exec (p, search_bytes, options, sub);
+ e = jit_exec (subject, line_end - subject, search_offset,
+ options, sub);
if (e != PCRE_ERROR_BADUTF8)
{
if (0 < e && multiline && sub[1] - sub[0] != 0)
{
- char const *nl = memchr (p + sub[0], eolbyte,
+ char const *nl = memchr (subject + sub[0], eolbyte,
sub[1] - sub[0]);
if (nl)
{
/* This match crosses a line boundary; reject it. */
- p += sub[0];
+ p = subject + sub[0];
line_end = nl;
continue;
}
@@ -261,22 +270,26 @@ Pexecute (char const *buf, size_t size, size_t *match_size,
}
int valid_bytes = sub[0];
- /* Try to match the string before the encoding error.
- Again, handle the empty-match case specially, for speed. */
- if (valid_bytes == 0)
+ /* Try to match the string before the encoding error. */
+ if (valid_bytes < search_offset)
+ e = PCRE_ERROR_NOMATCH;
+ else if (valid_bytes == 0)
{
+ /* Handle the empty-match case specially, for speed.
+ This optimization is valid if VALID_BYTES is zero,
+ which means SEARCH_OFFSET is also zero. */
sub[1] = 0;
e = empty_match[bol];
}
else
- e = pcre_exec (cre, extra, p, valid_bytes, 0,
- options | PCRE_NO_UTF8_CHECK | PCRE_NOTEOL,
- sub, NSUB);
+ e = jit_exec (subject, valid_bytes, search_offset,
+ options | PCRE_NO_UTF8_CHECK | PCRE_NOTEOL, sub);
+
if (e != PCRE_ERROR_NOMATCH)
break;
/* Treat the encoding error as data that cannot match. */
- p += valid_bytes + 1;
+ p = subject += valid_bytes + 1;
bol = false;
}
@@ -315,8 +328,8 @@ Pexecute (char const *buf, size_t size, size_t *match_size,
}
else
{
- char const *matchbeg = p + sub[0];
- char const *matchend = p + sub[1];
+ char const *matchbeg = subject + sub[0];
+ char const *matchend = subject + sub[1];
char const *beg;
char const *end;
if (start_ptr)
diff --git a/tests/Makefile.am b/tests/Makefile.am
index 2d7ebf6..7bceac7 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -92,6 +92,7 @@ TESTS = \
options \
pcre \
pcre-abort \
+ pcre-context \
pcre-infloop \
pcre-invalid-utf8-input \
pcre-jitstack \
diff --git a/tests/pcre-context b/tests/pcre-context
new file mode 100755
index 0000000..f0c96e0
--- /dev/null
+++ b/tests/pcre-context
@@ -0,0 +1,38 @@
+#!/bin/sh
+# Test Perl regex with context
+. "${srcdir=.}/init.sh"; path_prepend_ ../src
+require_pcre_
+
+cat >in <<'EOF'
+Preceded by 0 empty lines.
+
+Preceded by 1 empty line.
+
+
+Preceded by 2 empty lines.
+
+
+
+Preceded by 3 empty lines.
+
+
+
+
+Preceded by 4 empty lines.
+
+EOF
+test $? -eq 0 || framework_failure_
+
+cat >exp <<'EOF'
+Preceded by 2 empty lines.
+Preceded by 3 empty lines.
+Preceded by 4 empty lines.
+EOF
+test $? -eq 0 || framework_failure_
+
+fail=0
+
+grep -Pzo '(?<=\n\n\n).*' in >out || fail_ 'grep -Pzo failed'
+compare exp out || fail=1
+
+Exit $fail
--
2.1.0
>From 36f8a291f87368072fd382cdcd9255b4163d6e1b Mon Sep 17 00:00:00 2001
From: Paul Eggert <egg...@cs.ucla.edu>
Date: Fri, 3 Jul 2015 08:11:53 -0700
Subject: [PATCH 2/2] grep: simplify print_line_middle slightly
* src/grep.c (print_line_middle): Simplify.
---
src/grep.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/src/grep.c b/src/grep.c
index d1581e3..778dbcb 100644
--- a/src/grep.c
+++ b/src/grep.c
@@ -1022,8 +1022,8 @@ print_line_middle (const char *beg, const char *lim,
const char *mid = NULL;
while (cur < lim
- && ((match_offset = execute (beg, lim - beg, &match_size,
- beg + (cur - beg))) != (size_t) -1))
+ && ((match_offset = execute (beg, lim - beg, &match_size, cur))
+ != (size_t) -1))
{
char const *b = beg + match_offset;
--
2.1.0
