diff options
Diffstat (limited to 'gnulib-m4/memchr.m4')
| -rw-r--r-- | gnulib-m4/memchr.m4 | 79 |
1 files changed, 43 insertions, 36 deletions
diff --git a/gnulib-m4/memchr.m4 b/gnulib-m4/memchr.m4 index 83c65c11..c7489d87 100644 --- a/gnulib-m4/memchr.m4 +++ b/gnulib-m4/memchr.m4 @@ -1,5 +1,5 @@ -# memchr.m4 serial 13 -dnl Copyright (C) 2002-2004, 2009-2018 Free Software Foundation, Inc. +# memchr.m4 serial 18 +dnl Copyright (C) 2002-2004, 2009-2022 Free Software Foundation, Inc. dnl This file is free software; the Free Software Foundation dnl gives unlimited permission to copy and/or distribute it, dnl with or without modifications, as long as this notice is preserved. @@ -13,25 +13,18 @@ AC_DEFUN_ONCE([gl_FUNC_MEMCHR], AC_CHECK_HEADERS_ONCE([sys/mman.h]) AC_CHECK_FUNCS_ONCE([mprotect]) - AC_REQUIRE([gl_HEADER_STRING_H_DEFAULTS]) - m4_ifdef([gl_FUNC_MEMCHR_OBSOLETE], [ - dnl These days, we assume memchr is present. But if support for old - dnl platforms is desired: - AC_CHECK_FUNCS_ONCE([memchr]) - if test $ac_cv_func_memchr = no; then - HAVE_MEMCHR=0 - fi - ]) - if test $HAVE_MEMCHR = 1; then - # Detect platform-specific bugs in some versions of glibc: - # memchr should not dereference anything with length 0 - # https://bugzilla.redhat.com/show_bug.cgi?id=499689 - # memchr should not dereference overestimated length after a match - # https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=521737 - # https://sourceware.org/bugzilla/show_bug.cgi?id=10162 - # Assume that memchr works on platforms that lack mprotect. - AC_CACHE_CHECK([whether memchr works], [gl_cv_func_memchr_works], - [AC_RUN_IFELSE([AC_LANG_PROGRAM([[ + AC_REQUIRE([gl_STRING_H_DEFAULTS]) + # Detect platform-specific bugs in some versions of glibc: + # memchr should not dereference anything with length 0 + # https://bugzilla.redhat.com/show_bug.cgi?id=499689 + # memchr should not dereference overestimated length after a match + # https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=521737 + # https://sourceware.org/bugzilla/show_bug.cgi?id=10162 + # memchr should cast the second argument to 'unsigned char'. + # This bug exists in Android 4.3. + # Assume that memchr works on platforms that lack mprotect. + AC_CACHE_CHECK([whether memchr works], [gl_cv_func_memchr_works], + [AC_RUN_IFELSE([AC_LANG_PROGRAM([[ #include <string.h> #if HAVE_SYS_MMAN_H # include <fcntl.h> @@ -66,6 +59,7 @@ AC_DEFUN_ONCE([gl_FUNC_MEMCHR], #endif if (fence) { + /* Test against bugs on glibc systems. */ if (memchr (fence, 0, 0)) result |= 1; strcpy (fence - 9, "12345678"); @@ -73,24 +67,37 @@ AC_DEFUN_ONCE([gl_FUNC_MEMCHR], result |= 2; if (memchr (fence - 1, 0, 3) != fence - 1) result |= 4; + /* Test against bug on AIX 7.2. */ + if (memchr (fence - 4, '6', 16) != fence - 4) + result |= 8; } + /* Test against bug on Android 4.3. */ + { + char input[3]; + input[0] = 'a'; + input[1] = 'b'; + input[2] = 'c'; + if (memchr (input, 0x789abc00 | 'b', 3) != input + 1) + result |= 16; + } return result; ]])], - [gl_cv_func_memchr_works=yes], - [gl_cv_func_memchr_works=no], - [case "$host_os" in - # Guess yes on native Windows. - mingw*) gl_cv_func_memchr_works="guessing yes" ;; - # Be pessimistic for now. - *) gl_cv_func_memchr_works="guessing no" ;; - esac - ]) - ]) - case "$gl_cv_func_memchr_works" in - *yes) ;; - *) REPLACE_MEMCHR=1 ;; - esac - fi + [gl_cv_func_memchr_works=yes], + [gl_cv_func_memchr_works=no], + [case "$host_os" in + # Guess no on Android. + linux*-android*) gl_cv_func_memchr_works="guessing no" ;; + # Guess yes on native Windows. + mingw*) gl_cv_func_memchr_works="guessing yes" ;; + # If we don't know, obey --enable-cross-guesses. + *) gl_cv_func_memchr_works="$gl_cross_guess_normal" ;; + esac + ]) + ]) + case "$gl_cv_func_memchr_works" in + *yes) ;; + *) REPLACE_MEMCHR=1 ;; + esac ]) # Prerequisites of lib/memchr.c. |