1# strcasestr.m4 serial 26 2dnl Copyright (C) 2005, 2007-2021 Free Software Foundation, Inc. 3dnl This file is free software; the Free Software Foundation 4dnl gives unlimited permission to copy and/or distribute it, 5dnl with or without modifications, as long as this notice is preserved. 6 7dnl Check that strcasestr is present and works. 8AC_DEFUN([gl_FUNC_STRCASESTR_SIMPLE], 9[ 10 AC_REQUIRE([gl_HEADER_STRING_H_DEFAULTS]) 11 12 dnl Persuade glibc <string.h> to declare strcasestr(). 13 AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS]) 14 15 AC_REQUIRE([gl_FUNC_MEMCHR]) 16 AC_CHECK_FUNCS([strcasestr]) 17 if test $ac_cv_func_strcasestr = no; then 18 HAVE_STRCASESTR=0 19 else 20 if test $REPLACE_MEMCHR = 1; then 21 REPLACE_STRCASESTR=1 22 else 23 dnl Detect https://sourceware.org/bugzilla/show_bug.cgi?id=12092 24 dnl and https://sourceware.org/bugzilla/show_bug.cgi?id=23637. 25 AC_CACHE_CHECK([whether strcasestr works], 26 [gl_cv_func_strcasestr_works_always], 27 [AC_RUN_IFELSE( 28 [AC_LANG_PROGRAM([[ 29#include <string.h> /* for strcasestr */ 30#ifdef __GNU_LIBRARY__ 31 #include <features.h> 32 #if __GLIBC__ == 2 && __GLIBC_MINOR__ == 28 33 Unlucky user 34 #endif 35#endif 36#define P "_EF_BF_BD" 37#define HAYSTACK "F_BD_CE_BD" P P P P "_C3_88_20" P P P "_C3_A7_20" P 38#define NEEDLE P P P P P 39]], 40 [[return !!strcasestr (HAYSTACK, NEEDLE); 41 ]])], 42 [gl_cv_func_strcasestr_works_always=yes], 43 [gl_cv_func_strcasestr_works_always=no], 44 [dnl glibc 2.12 and cygwin 1.7.7 have a known bug. uClibc is not 45 dnl affected, since it uses different source code for strcasestr 46 dnl than glibc. 47 dnl Assume that it works on all other platforms, even if it is not 48 dnl linear. 49 AC_EGREP_CPP([Lucky user], 50 [ 51#ifdef __GNU_LIBRARY__ 52 #include <features.h> 53 #if ((__GLIBC__ == 2 && __GLIBC_MINOR__ > 12) || (__GLIBC__ > 2)) \ 54 || defined __UCLIBC__ 55 Lucky user 56 #endif 57#elif defined __CYGWIN__ 58 #include <cygwin/version.h> 59 #if CYGWIN_VERSION_DLL_COMBINED > CYGWIN_VERSION_DLL_MAKE_COMBINED (1007, 7) 60 Lucky user 61 #endif 62#else 63 Lucky user 64#endif 65 ], 66 [gl_cv_func_strcasestr_works_always="guessing yes"], 67 [gl_cv_func_strcasestr_works_always="$gl_cross_guess_normal"]) 68 ]) 69 ]) 70 case "$gl_cv_func_strcasestr_works_always" in 71 *yes) ;; 72 *) 73 REPLACE_STRCASESTR=1 74 ;; 75 esac 76 fi 77 fi 78]) # gl_FUNC_STRCASESTR_SIMPLE 79 80dnl Additionally, check that strcasestr is efficient. 81AC_DEFUN([gl_FUNC_STRCASESTR], 82[ 83 AC_REQUIRE([gl_FUNC_STRCASESTR_SIMPLE]) 84 if test $HAVE_STRCASESTR = 1 && test $REPLACE_STRCASESTR = 0; then 85 AC_CACHE_CHECK([whether strcasestr works in linear time], 86 [gl_cv_func_strcasestr_linear], 87 [AC_RUN_IFELSE([AC_LANG_PROGRAM([[ 88#include <signal.h> /* for signal */ 89#include <string.h> /* for strcasestr */ 90#include <stdlib.h> /* for malloc */ 91#include <unistd.h> /* for alarm */ 92static void quit (int sig) { _exit (sig + 128); } 93]], [[ 94 int result = 0; 95 size_t m = 1000000; 96 char *haystack = (char *) malloc (2 * m + 2); 97 char *needle = (char *) malloc (m + 2); 98 /* Failure to compile this test due to missing alarm is okay, 99 since all such platforms (mingw) also lack strcasestr. */ 100 signal (SIGALRM, quit); 101 alarm (5); 102 /* Check for quadratic performance. */ 103 if (haystack && needle) 104 { 105 memset (haystack, 'A', 2 * m); 106 haystack[2 * m] = 'B'; 107 haystack[2 * m + 1] = 0; 108 memset (needle, 'A', m); 109 needle[m] = 'B'; 110 needle[m + 1] = 0; 111 if (!strcasestr (haystack, needle)) 112 result |= 1; 113 } 114 /* Free allocated memory, in case some sanitizer is watching. */ 115 free (haystack); 116 free (needle); 117 return result; 118 ]])], 119 [gl_cv_func_strcasestr_linear=yes], [gl_cv_func_strcasestr_linear=no], 120 [dnl Only glibc > 2.12 and cygwin > 1.7.7 are known to have a 121 dnl strcasestr that works in linear time. 122 AC_EGREP_CPP([Lucky user], 123 [ 124#include <features.h> 125#ifdef __GNU_LIBRARY__ 126 #if ((__GLIBC__ == 2 && __GLIBC_MINOR__ > 12) || (__GLIBC__ > 2)) \ 127 && !defined __UCLIBC__ 128 Lucky user 129 #endif 130#endif 131#ifdef __CYGWIN__ 132 #include <cygwin/version.h> 133 #if CYGWIN_VERSION_DLL_COMBINED > CYGWIN_VERSION_DLL_MAKE_COMBINED (1007, 7) 134 Lucky user 135 #endif 136#endif 137 ], 138 [gl_cv_func_strcasestr_linear="guessing yes"], 139 [gl_cv_func_strcasestr_linear="$gl_cross_guess_normal"]) 140 ]) 141 ]) 142 case "$gl_cv_func_strcasestr_linear" in 143 *yes) ;; 144 *) 145 REPLACE_STRCASESTR=1 146 ;; 147 esac 148 fi 149]) # gl_FUNC_STRCASESTR 150 151# Prerequisites of lib/strcasestr.c. 152AC_DEFUN([gl_PREREQ_STRCASESTR], [ 153 : 154]) 155