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[PATCH] memmem, strstr, strcasestr: fix bug with long periodic needle
|
From: |
Eric Blake |
|
Subject: |
[PATCH] memmem, strstr, strcasestr: fix bug with long periodic needle |
|
Date: |
Tue, 5 Oct 2010 17:09:41 -0600 |
* lib/str-two-way.h (two_way_long_needle): Avoid bug with long
periodic needle having false positive.
* m4/memmem.m4 (gl_FUNC_MEMMEM_SIMPLE): Detect bug in glibc 2.12
and cygwin 1.7.7.
(gl_FUNC_MEMMEM): Be more pessimistic when cross-compiling.
* m4/strcasestr.m4 (gl_FUNC_STRCASESTR_SIMPLE)
(gl_FUNC_STRCASESTR): Likewise.
* m4/strstr.m4 (gl_FUNC_STRSTR_SIMPLE, gl_FUNC_STRSTR): Likewise.
* tests/test-memmem.c (main): Expose the bug.
* tests/test-strcasestr.c (main): Likewise.
* tests/test-strstr.c (main): Likewise.
* tests/test-c-strcasestr.c (main): Likewise.
* doc/glibc-functions/memmem.texi (memmem): Document the bug.
* doc/posix-functions/strstr.texi (strstr): Likewise.
* doc/glibc-functions/strcasestr.texi (strcasestr): Likewise.
Reported via http://sourceware.org/bugzilla/show_bug.cgi?id=12092
Signed-off-by: Eric Blake <address@hidden>
---
Rather a large patch for just a 2-line fix shared among three modules :)
ChangeLog | 20 +++++++++++
doc/glibc-functions/memmem.texi | 4 ++
doc/glibc-functions/strcasestr.texi | 5 +++
doc/posix-functions/strstr.texi | 4 ++
lib/str-two-way.h | 2 +-
m4/memmem.m4 | 61 ++++++++++++++++++++++++++++------
m4/strcasestr.m4 | 49 +++++++++++++++++++++++++---
m4/strstr.m4 | 51 +++++++++++++++++++++++++---
tests/test-c-strcasestr.c | 19 +++++++++++
tests/test-memmem.c | 19 +++++++++++
tests/test-strcasestr.c | 19 +++++++++++
tests/test-strstr.c | 19 +++++++++++
12 files changed, 249 insertions(+), 23 deletions(-)
diff --git a/ChangeLog b/ChangeLog
index 53a861f..19b5be8 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,23 @@
+2010-10-05 Eric Blake <address@hidden>
+
+ memmem, strstr, strcasestr: fix bug with long periodic needle
+ * lib/str-two-way.h (two_way_long_needle): Avoid bug with long
+ periodic needle having false positive.
+ * m4/memmem.m4 (gl_FUNC_MEMMEM_SIMPLE): Detect bug in glibc 2.12
+ and cygwin 1.7.7.
+ (gl_FUNC_MEMMEM): Be more pessimistic when cross-compiling.
+ * m4/strcasestr.m4 (gl_FUNC_STRCASESTR_SIMPLE)
+ (gl_FUNC_STRCASESTR): Likewise.
+ * m4/strstr.m4 (gl_FUNC_STRSTR_SIMPLE, gl_FUNC_STRSTR): Likewise.
+ * tests/test-memmem.c (main): Expose the bug.
+ * tests/test-strcasestr.c (main): Likewise.
+ * tests/test-strstr.c (main): Likewise.
+ * tests/test-c-strcasestr.c (main): Likewise.
+ * doc/glibc-functions/memmem.texi (memmem): Document the bug.
+ * doc/posix-functions/strstr.texi (strstr): Likewise.
+ * doc/glibc-functions/strcasestr.texi (strcasestr): Likewise.
+ Reported via http://sourceware.org/bugzilla/show_bug.cgi?id=12092
+
2010-10-05 Paul Eggert <address@hidden>
parse-datetime: do some more renaming
diff --git a/doc/glibc-functions/memmem.texi b/doc/glibc-functions/memmem.texi
index c7e3d73..0cfcdd9 100644
--- a/doc/glibc-functions/memmem.texi
+++ b/doc/glibc-functions/memmem.texi
@@ -13,6 +13,10 @@ memmem
@item
This function has reversed arguments on some older platforms:
Linux libc 5.0.9
address@hidden
+This function can trigger false positives for long periodic needles on
+some platforms:
+glibc 2.12, Cygwin 1.7.7.
@end itemize
Portability problems fixed by Gnulib module @code{memmem}:
diff --git a/doc/glibc-functions/strcasestr.texi
b/doc/glibc-functions/strcasestr.texi
index 7ce39f4..d75aeaa 100644
--- a/doc/glibc-functions/strcasestr.texi
+++ b/doc/glibc-functions/strcasestr.texi
@@ -15,6 +15,11 @@ strcasestr
@item
This function can trigger memchr bugs on some platforms:
glibc 2.10.
+
address@hidden
+This function can trigger false positives for long periodic needles on
+some platforms:
+glibc 2.12, Cygwin 1.7.7.
@end itemize
Portability problems fixed by Gnulib module @code{strcasestr}:
diff --git a/doc/posix-functions/strstr.texi b/doc/posix-functions/strstr.texi
index 61bb35b..40d20b0 100644
--- a/doc/posix-functions/strstr.texi
+++ b/doc/posix-functions/strstr.texi
@@ -12,6 +12,10 @@ strstr
@item
This function can trigger memchr bugs on some platforms:
glibc 2.10.
address@hidden
+This function can trigger false positives for long periodic needles on
+some platforms:
+glibc 2.12, Cygwin 1.7.7.
@end itemize
Portability problems fixed by Gnulib @code{strstr}:
diff --git a/lib/str-two-way.h b/lib/str-two-way.h
index dbc2f88..5f150af 100644
--- a/lib/str-two-way.h
+++ b/lib/str-two-way.h
@@ -370,8 +370,8 @@ two_way_long_needle (const unsigned char *haystack, size_t
haystack_len,
a byte out of place, there can be no match until
after the mismatch. */
shift = needle_len - period;
- memory = 0;
}
+ memory = 0;
j += shift;
continue;
}
diff --git a/m4/memmem.m4 b/m4/memmem.m4
index d02b993..553a81c 100644
--- a/m4/memmem.m4
+++ b/m4/memmem.m4
@@ -1,4 +1,4 @@
-# memmem.m4 serial 15
+# memmem.m4 serial 16
dnl Copyright (C) 2002, 2003, 2004, 2007, 2008, 2009, 2010 Free Software
dnl Foundation, Inc.
dnl This file is free software; the Free Software Foundation
@@ -16,6 +16,45 @@ AC_DEFUN([gl_FUNC_MEMMEM_SIMPLE],
AC_CHECK_DECLS_ONCE([memmem])
if test $ac_cv_have_decl_memmem = no; then
HAVE_DECL_MEMMEM=0
+ else
+ dnl Detect http://sourceware.org/bugzilla/show_bug.cgi?id=12092.
+ AC_CACHE_CHECK([whether memmem works],
+ [gl_cv_func_memmem_works_always],
+ [AC_RUN_IFELSE([AC_LANG_PROGRAM([[
+#include <string.h> /* for memmem */
+#define P "_EF_BF_BD"
+#define HAYSTACK "F_BD_CE_BD" P P P P "_C3_88_20" P P P "_C3_A7_20" P
+#define NEEDLE P P P P P
+]], [[return !!memmem (HAYSTACK, strlen (HAYSTACK), NEEDLE, strlen (NEEDLE));
+ ]])],
+ [gl_cv_func_memmem_works_always=yes],
+ [gl_cv_func_memmem_works_always=no],
+ [dnl glibc 2.12 and cygwin 1.7.7 have a known bug. Assume that it
+ dnl works on all other platforms, even if it is not linear.
+ AC_EGREP_CPP([Lucky user],
+ [
+#ifdef __GNU_LIBRARY__
+ #include <features.h>
+ #if (__GLIBC__ == 2 && __GLIBC_MINOR__ > 12) || (__GLIBC__ > 2)
+ Lucky user
+ #endif
+#elif defined __CYGWIN__
+ #include <cygwin/version.h>
+ #if CYGWIN_VERSION_DLL_MAJOR >= 1007 && CYGWIN_VERSION_DLL_MINOR > 7
+ Lucky user
+ #endif
+#else
+ Lucky user
+#endif
+ ],
+ [gl_cv_func_memmem_works_always=yes],
+ [gl_cv_func_memmem_works_always="guessing no"])
+ ])
+ ])
+ if test "$gl_cv_func_memmem_works_always" != yes; then
+ REPLACE_MEMMEM=1
+ AC_LIBOBJ([memmem])
+ fi
fi
gl_PREREQ_MEMMEM
]) # gl_FUNC_MEMMEM_SIMPLE
@@ -24,9 +63,9 @@ dnl Additionally, check that memmem is efficient and handles
empty needles.
AC_DEFUN([gl_FUNC_MEMMEM],
[
AC_REQUIRE([gl_FUNC_MEMMEM_SIMPLE])
- if test $ac_cv_have_decl_memmem = yes; then
+ if test $HAVE_MEMMEM = 1 && test $REPLACE_MEMMEM = 0; then
AC_CACHE_CHECK([whether memmem works in linear time],
- [gl_cv_func_memmem_works],
+ [gl_cv_func_memmem_works_fast],
[AC_RUN_IFELSE([AC_LANG_PROGRAM([[
#include <signal.h> /* for signal */
#include <string.h> /* for memmem */
@@ -52,29 +91,29 @@ static void quit (int sig) { exit (sig + 128); }
}
/* Check for empty needle behavior. */
return !result || !memmem ("a", 1, 0, 0);]])],
- [gl_cv_func_memmem_works=yes], [gl_cv_func_memmem_works=no],
- [dnl Only glibc >= 2.9 and cygwin >= 1.7.0 are known to have a
- dnl memmem that works in linear time.
+ [gl_cv_func_memmem_works_fast=yes], [gl_cv_func_memmem_works_fast=no],
+ [dnl Only glibc > 2.12 and cygwin > 1.7.7 are known to have a
+ dnl bug-free memmem that works in linear time.
AC_EGREP_CPP([Lucky user],
[
#include <features.h>
#ifdef __GNU_LIBRARY__
- #if (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 9) || (__GLIBC__ > 2)
+ #if (__GLIBC__ == 2 && __GLIBC_MINOR__ > 12) || (__GLIBC__ > 2)
Lucky user
#endif
#endif
#ifdef __CYGWIN__
#include <cygwin/version.h>
- #if CYGWIN_VERSION_DLL_MAJOR >= 1007
+ #if CYGWIN_VERSION_DLL_MAJOR >= 1007 && CYGWIN_VERSION_DLL_MINOR > 7
Lucky user
#endif
#endif
],
- [gl_cv_func_memmem_works=yes],
- [gl_cv_func_memmem_works="guessing no"])
+ [gl_cv_func_memmem_works_fast=yes],
+ [gl_cv_func_memmem_works_fast="guessing no"])
])
])
- if test "$gl_cv_func_memmem_works" != yes; then
+ if test "$gl_cv_func_memmem_works_fast" != yes; then
REPLACE_MEMMEM=1
AC_LIBOBJ([memmem])
fi
diff --git a/m4/strcasestr.m4 b/m4/strcasestr.m4
index 50ac0a7..f0c4a6e 100644
--- a/m4/strcasestr.m4
+++ b/m4/strcasestr.m4
@@ -1,4 +1,4 @@
-# strcasestr.m4 serial 14
+# strcasestr.m4 serial 15
dnl Copyright (C) 2005, 2007, 2008, 2009, 2010 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
@@ -19,6 +19,45 @@ AC_DEFUN([gl_FUNC_STRCASESTR_SIMPLE],
else
if test "$gl_cv_func_memchr_works" != yes; then
REPLACE_STRCASESTR=1
+ else
+ dnl Detect http://sourceware.org/bugzilla/show_bug.cgi?id=12092.
+ AC_CACHE_CHECK([whether strcasestr works],
+ [gl_cv_func_strcasestr_works_always],
+ [AC_RUN_IFELSE([AC_LANG_PROGRAM([[
+#include <string.h> /* for strcasestr */
+#define P "_EF_BF_BD"
+#define HAYSTACK "F_BD_CE_BD" P P P P "_C3_88_20" P P P "_C3_A7_20" P
+#define NEEDLE P P P P P
+]], [[return !!strcasestr (HAYSTACK, NEEDLE);
+ ]])],
+ [gl_cv_func_strcasestr_works_always=yes],
+ [gl_cv_func_strcasestr_works_always=no],
+ [dnl glibc 2.12 and cygwin 1.7.7 have a known bug. Assume that it
+ dnl works on all other platforms, even if it is not linear.
+ AC_EGREP_CPP([Lucky user],
+ [
+#ifdef __GNU_LIBRARY__
+ #include <features.h>
+ #if (__GLIBC__ == 2 && __GLIBC_MINOR__ > 12) || (__GLIBC__ > 2)
+ Lucky user
+ #endif
+#elif defined __CYGWIN__
+ #include <cygwin/version.h>
+ #if CYGWIN_VERSION_DLL_MAJOR >= 1007 && CYGWIN_VERSION_DLL_MINOR > 7
+ Lucky user
+ #endif
+#else
+ Lucky user
+#endif
+ ],
+ [gl_cv_func_strcasestr_works_always=yes],
+ [gl_cv_func_strcasestr_works_always="guessing no"])
+ ])
+ ])
+ if test "$gl_cv_func_strcasestr_works_always" != yes; then
+ REPLACE_STRCASESTR=1
+ AC_LIBOBJ([strcasestr])
+ fi
fi
fi
if test $HAVE_STRCASESTR = 0 || test $REPLACE_STRCASESTR = 1; then
@@ -36,7 +75,7 @@ AC_DEFUN([gl_FUNC_STRCASESTR],
[gl_cv_func_strcasestr_linear],
[AC_RUN_IFELSE([AC_LANG_PROGRAM([[
#include <signal.h> /* for signal */
-#include <string.h> /* for memmem */
+#include <string.h> /* for strcasestr */
#include <stdlib.h> /* for malloc */
#include <unistd.h> /* for alarm */
static void quit (int sig) { exit (sig + 128); }
@@ -61,19 +100,19 @@ static void quit (int sig) { exit (sig + 128); }
}
return !result;]])],
[gl_cv_func_strcasestr_linear=yes], [gl_cv_func_strcasestr_linear=no],
- [dnl Only glibc >= 2.9 and cygwin >= 1.7.0 are known to have a
+ [dnl Only glibc > 2.12 and cygwin > 1.7.7 are known to have a
dnl strcasestr that works in linear time.
AC_EGREP_CPP([Lucky user],
[
#include <features.h>
#ifdef __GNU_LIBRARY__
- #if (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 9) || (__GLIBC__ > 2)
+ #if (__GLIBC__ == 2 && __GLIBC_MINOR__ > 12) || (__GLIBC__ > 2)
Lucky user
#endif
#endif
#ifdef __CYGWIN__
#include <cygwin/version.h>
- #if CYGWIN_VERSION_DLL_MAJOR >= 1007
+ #if CYGWIN_VERSION_DLL_MAJOR >= 1007 && CYGWIN_VERSION_DLL_MINOR > 7
Lucky user
#endif
#endif
diff --git a/m4/strstr.m4 b/m4/strstr.m4
index 3e45a7a..1880150 100644
--- a/m4/strstr.m4
+++ b/m4/strstr.m4
@@ -1,4 +1,4 @@
-# strstr.m4 serial 8
+# strstr.m4 serial 9
dnl Copyright (C) 2008, 2009, 2010 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
@@ -12,6 +12,45 @@ AC_DEFUN([gl_FUNC_STRSTR_SIMPLE],
if test "$gl_cv_func_memchr_works" != yes; then
REPLACE_STRSTR=1
AC_LIBOBJ([strstr])
+ else
+ dnl Detect http://sourceware.org/bugzilla/show_bug.cgi?id=12092.
+ AC_CACHE_CHECK([whether strstr works],
+ [gl_cv_func_strstr_works_always],
+ [AC_RUN_IFELSE([AC_LANG_PROGRAM([[
+#include <string.h> /* for strstr */
+#define P "_EF_BF_BD"
+#define HAYSTACK "F_BD_CE_BD" P P P P "_C3_88_20" P P P "_C3_A7_20" P
+#define NEEDLE P P P P P
+]], [[return !!strstr (HAYSTACK, NEEDLE);
+ ]])],
+ [gl_cv_func_strstr_works_always=yes],
+ [gl_cv_func_strstr_works_always=no],
+ [dnl glibc 2.12 and cygwin 1.7.7 have a known bug. Assume that it
+ dnl works on all other platforms, even if it is not linear.
+ AC_EGREP_CPP([Lucky user],
+ [
+#ifdef __GNU_LIBRARY__
+ #include <features.h>
+ #if (__GLIBC__ == 2 && __GLIBC_MINOR__ > 12) || (__GLIBC__ > 2)
+ Lucky user
+ #endif
+#elif defined __CYGWIN__
+ #include <cygwin/version.h>
+ #if CYGWIN_VERSION_DLL_MAJOR >= 1007 && CYGWIN_VERSION_DLL_MINOR > 7
+ Lucky user
+ #endif
+#else
+ Lucky user
+#endif
+ ],
+ [gl_cv_func_strstr_works_always=yes],
+ [gl_cv_func_strstr_works_always="guessing no"])
+ ])
+ ])
+ if test "$gl_cv_func_strstr_works_always" != yes; then
+ REPLACE_STRSTR=1
+ AC_LIBOBJ([strstr])
+ fi
fi
]) # gl_FUNC_STRSTR_SIMPLE
@@ -24,7 +63,7 @@ AC_DEFUN([gl_FUNC_STRSTR],
[gl_cv_func_strstr_linear],
[AC_RUN_IFELSE([AC_LANG_PROGRAM([[
#include <signal.h> /* for signal */
-#include <string.h> /* for memmem */
+#include <string.h> /* for strstr */
#include <stdlib.h> /* for malloc */
#include <unistd.h> /* for alarm */
static void quit (int sig) { exit (sig + 128); }
@@ -49,19 +88,19 @@ static void quit (int sig) { exit (sig + 128); }
}
return !result;]])],
[gl_cv_func_strstr_linear=yes], [gl_cv_func_strstr_linear=no],
- [dnl Only glibc >= 2.9 and cygwin >= 1.7.0 are known to have a
- dnl strstr that works in linear time.
+ [dnl Only glibc > 2.12 and cygwin > 1.7.7 are known to have a
+ dnl bug-free strstr that works in linear time.
AC_EGREP_CPP([Lucky user],
[
#include <features.h>
#ifdef __GNU_LIBRARY__
- #if (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 9) || (__GLIBC__ > 2)
+ #if (__GLIBC__ == 2 && __GLIBC_MINOR__ > 12) || (__GLIBC__ > 2)
Lucky user
#endif
#endif
#ifdef __CYGWIN__
#include <cygwin/version.h>
- #if CYGWIN_VERSION_DLL_MAJOR >= 1007
+ #if CYGWIN_VERSION_DLL_MAJOR >= 1007 && CYGWIN_VERSION_DLL_MINOR > 7
Lucky user
#endif
#endif
diff --git a/tests/test-c-strcasestr.c b/tests/test-c-strcasestr.c
index 73723c7..52d55e8 100644
--- a/tests/test-c-strcasestr.c
+++ b/tests/test-c-strcasestr.c
@@ -58,6 +58,25 @@ main ()
ASSERT (result == input + 11);
}
+ /* Check that a long periodic needle does not cause false positives. */
+ {
+ const char input[] = ("F_BD_CE_BD_EF_BF_BD_EF_BF_BD_EF_BF_BD_EF_BF_BD"
+ "_C3_88_20_EF_BF_BD_EF_BF_BD_EF_BF_BD"
+ "_C3_A7_20_EF_BF_BD");
+ const char need[] = "_EF_BF_BD_EF_BF_BD_EF_BF_BD_EF_BF_BD_EF_BF_BD";
+ const char *result = c_strcasestr (input, need);
+ ASSERT (result == NULL);
+ }
+ {
+ const char input[] = ("F_BD_CE_BD_EF_BF_BD_EF_BF_BD_EF_BF_BD_EF_BF_BD"
+ "_C3_88_20_EF_BF_BD_EF_BF_BD_EF_BF_BD"
+ "_C3_A7_20_EF_BF_BD_DA_B5_C2_A6_20"
+ "_EF_BF_BD_EF_BF_BD_EF_BF_BD_EF_BF_BD_EF_BF_BD");
+ const char need[] = "_EF_BF_BD_EF_BF_BD_EF_BF_BD_EF_BF_BD_EF_BF_BD";
+ const char *result = c_strcasestr (input, need);
+ ASSERT (result == input + 115);
+ }
+
/* Check that a very long haystack is handled quickly if the needle is
short and occurs near the beginning. */
{
diff --git a/tests/test-memmem.c b/tests/test-memmem.c
index 3a21213..da0d1be 100644
--- a/tests/test-memmem.c
+++ b/tests/test-memmem.c
@@ -89,6 +89,25 @@ main (int argc, char *argv[])
ASSERT (result == input);
}
+ /* Check that a long periodic needle does not cause false positives. */
+ {
+ const char input[] = ("F_BD_CE_BD_EF_BF_BD_EF_BF_BD_EF_BF_BD_EF_BF_BD"
+ "_C3_88_20_EF_BF_BD_EF_BF_BD_EF_BF_BD"
+ "_C3_A7_20_EF_BF_BD");
+ const char need[] = "_EF_BF_BD_EF_BF_BD_EF_BF_BD_EF_BF_BD_EF_BF_BD";
+ const char *result = memmem (input, strlen (input), need, strlen (need));
+ ASSERT (result == NULL);
+ }
+ {
+ const char input[] = ("F_BD_CE_BD_EF_BF_BD_EF_BF_BD_EF_BF_BD_EF_BF_BD"
+ "_C3_88_20_EF_BF_BD_EF_BF_BD_EF_BF_BD"
+ "_C3_A7_20_EF_BF_BD_DA_B5_C2_A6_20"
+ "_EF_BF_BD_EF_BF_BD_EF_BF_BD_EF_BF_BD_EF_BF_BD");
+ const char need[] = "_EF_BF_BD_EF_BF_BD_EF_BF_BD_EF_BF_BD_EF_BF_BD";
+ const char *result = memmem (input, strlen (input), need, strlen (need));
+ ASSERT (result == input + 115);
+ }
+
/* Check that a very long haystack is handled quickly if the needle is
short and occurs near the beginning. */
{
diff --git a/tests/test-strcasestr.c b/tests/test-strcasestr.c
index 1f38fad..c56fbae 100644
--- a/tests/test-strcasestr.c
+++ b/tests/test-strcasestr.c
@@ -71,6 +71,25 @@ main ()
ASSERT (result == input + 11);
}
+ /* Check that a long periodic needle does not cause false positives. */
+ {
+ const char input[] = ("F_BD_CE_BD_EF_BF_BD_EF_BF_BD_EF_BF_BD_EF_BF_BD"
+ "_C3_88_20_EF_BF_BD_EF_BF_BD_EF_BF_BD"
+ "_C3_A7_20_EF_BF_BD");
+ const char need[] = "_EF_BF_BD_EF_BF_BD_EF_BF_BD_EF_BF_BD_EF_BF_BD";
+ const char *result = strcasestr (input, need);
+ ASSERT (result == NULL);
+ }
+ {
+ const char input[] = ("F_BD_CE_BD_EF_BF_BD_EF_BF_BD_EF_BF_BD_EF_BF_BD"
+ "_C3_88_20_EF_BF_BD_EF_BF_BD_EF_BF_BD"
+ "_C3_A7_20_EF_BF_BD_DA_B5_C2_A6_20"
+ "_EF_BF_BD_EF_BF_BD_EF_BF_BD_EF_BF_BD_EF_BF_BD");
+ const char need[] = "_EF_BF_BD_EF_BF_BD_EF_BF_BD_EF_BF_BD_EF_BF_BD";
+ const char *result = strcasestr (input, need);
+ ASSERT (result == input + 115);
+ }
+
/* Check that a very long haystack is handled quickly if the needle is
short and occurs near the beginning. */
{
diff --git a/tests/test-strstr.c b/tests/test-strstr.c
index 1482e7d..1ddd015 100644
--- a/tests/test-strstr.c
+++ b/tests/test-strstr.c
@@ -91,6 +91,25 @@ main (int argc, char *argv[])
ASSERT (result == input + 11);
}
+ /* Check that a long periodic needle does not cause false positives. */
+ {
+ const char input[] = ("F_BD_CE_BD_EF_BF_BD_EF_BF_BD_EF_BF_BD_EF_BF_BD"
+ "_C3_88_20_EF_BF_BD_EF_BF_BD_EF_BF_BD"
+ "_C3_A7_20_EF_BF_BD");
+ const char need[] = "_EF_BF_BD_EF_BF_BD_EF_BF_BD_EF_BF_BD_EF_BF_BD";
+ const char *result = strstr (input, need);
+ ASSERT (result == NULL);
+ }
+ {
+ const char input[] = ("F_BD_CE_BD_EF_BF_BD_EF_BF_BD_EF_BF_BD_EF_BF_BD"
+ "_C3_88_20_EF_BF_BD_EF_BF_BD_EF_BF_BD"
+ "_C3_A7_20_EF_BF_BD_DA_B5_C2_A6_20"
+ "_EF_BF_BD_EF_BF_BD_EF_BF_BD_EF_BF_BD_EF_BF_BD");
+ const char need[] = "_EF_BF_BD_EF_BF_BD_EF_BF_BD_EF_BF_BD_EF_BF_BD";
+ const char *result = strstr (input, need);
+ ASSERT (result == input + 115);
+ }
+
/* Check that a very long haystack is handled quickly if the needle is
short and occurs near the beginning. */
{
--
1.7.2.3