| 1 | dnl @synopsis AC_PROG_CC_NO_WRITEABLE_STRINGS(substvar [,hard]) |
| 2 | dnl |
| 3 | dnl Try to find a compiler option that warns when a stringliteral is |
| 4 | dnl used in a place that could potentially modify the address. This |
| 5 | dnl should warn on giving an stringliteral to a function that asks of |
| 6 | dnl a non-const-modified char-pointer. |
| 7 | dnl |
| 8 | dnl The sanity check is done by looking at string.h which has a set |
| 9 | dnl of strcpy definitions that should be defined with const-modifiers |
| 10 | dnl to not emit a warning in all so many places. |
| 11 | dnl |
| 12 | dnl Currently this macro knows about GCC. |
| 13 | dnl hopefully will evolve to use: Solaris C compiler, |
| 14 | dnl Digital Unix C compiler, C for AIX Compiler, HP-UX C compiler, |
| 15 | dnl and IRIX C compiler. |
| 16 | dnl |
| 17 | dnl @version $Id: ac_prog_cc_no_writeable_strings.m4,v 1.1 2002/02/20 16:18:18 steve Exp $ |
| 18 | dnl @author Guido Draheim <guidod@gmx.de> |
| 19 | |
| 20 | dnl [This appears to be a previous version of |
| 21 | dnl ax_cflags_no_writable_strings.m4 which is nowadays to be found in |
| 22 | dnl the Autoconf Archive. It was imported there on 2007-02-14 |
| 23 | dnl in commit 16aee45643e593e2833e4dff19df7b5f14267a79 where the file |
| 24 | dnl has a GPLv2 permission notice. Therefore I feel justified in |
| 25 | dnl adding the copyright permission notice below: -iwj] |
| 26 | dnl |
| 27 | dnl This file is Free Software. It has been copied into secnet. |
| 28 | dnl |
| 29 | dnl Copyright 2002 Guido Draheim |
| 30 | dnl |
| 31 | dnl You may redistribute secnet as a whole and/or modify it under the |
| 32 | dnl terms of the GNU General Public License as published by the Free |
| 33 | dnl Software Foundation; either version 3, or (at your option) any |
| 34 | dnl later version. |
| 35 | dnl |
| 36 | dnl You may redistribute this file and/or modify it under the terms of |
| 37 | dnl the GNU General Public License as published by the Free Software |
| 38 | dnl Foundation; either version 2, or (at your option) any later |
| 39 | dnl version. |
| 40 | dnl |
| 41 | dnl This software is distributed in the hope that it will be useful, |
| 42 | dnl but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 43 | dnl MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 44 | dnl GNU General Public License for more details. |
| 45 | dnl |
| 46 | dnl You should have received a copy of the GNU General Public License |
| 47 | dnl along with this software; if not, see |
| 48 | dnl https://www.gnu.org/licenses/gpl.html. |
| 49 | |
| 50 | AC_DEFUN([AC_PROG_CC_NO_WRITEABLE_STRINGS], [ |
| 51 | pushdef([CV],ac_cv_prog_cc_no_writeable_strings)dnl |
| 52 | hard=$2 |
| 53 | if test -z "$hard"; then |
| 54 | msg="C to warn about writing to stringliterals" |
| 55 | else |
| 56 | msg="C to prohibit any write to stringliterals" |
| 57 | fi |
| 58 | AC_CACHE_CHECK($msg, CV, [ |
| 59 | cat > conftest.c <<EOF |
| 60 | #include <string.h> |
| 61 | int main (void) |
| 62 | { |
| 63 | char test[[16]]; |
| 64 | if (strcpy (test, "test")) return 0; |
| 65 | return 1; |
| 66 | } |
| 67 | EOF |
| 68 | dnl GCC |
| 69 | if test "$GCC" = "yes"; |
| 70 | then |
| 71 | if test -z "$hard"; then |
| 72 | CV="-Wwrite-strings" |
| 73 | else |
| 74 | CV="-fno-writable-strings -Wwrite-strings" |
| 75 | fi |
| 76 | |
| 77 | if test -n "`${CC-cc} -c $CV conftest.c 2>&1`" ; then |
| 78 | CV="suppressed: string.h" |
| 79 | fi |
| 80 | |
| 81 | dnl Solaris C compiler |
| 82 | elif $CC -flags 2>&1 | grep "Xc.*strict ANSI C" > /dev/null 2>&1 && |
| 83 | $CC -c -xstrconst conftest.c > /dev/null 2>&1 && |
| 84 | test -f conftest.o |
| 85 | then |
| 86 | # strings go into readonly segment |
| 87 | CV="-xstrconst" |
| 88 | |
| 89 | rm conftest.o |
| 90 | if test -n "`${CC-cc} -c $CV conftest.c 2>&1`" ; then |
| 91 | CV="suppressed: string.h" |
| 92 | fi |
| 93 | |
| 94 | dnl HP-UX C compiler |
| 95 | elif $CC > /dev/null 2>&1 && |
| 96 | $CC -c +ESlit conftest.c > /dev/null 2>&1 && |
| 97 | test -f conftest.o |
| 98 | then |
| 99 | # strings go into readonly segment |
| 100 | CV="+ESlit" |
| 101 | |
| 102 | rm conftest.o |
| 103 | if test -n "`${CC-cc} -c $CV conftest.c 2>&1`" ; then |
| 104 | CV="suppressed: string.h" |
| 105 | fi |
| 106 | |
| 107 | dnl Digital Unix C compiler |
| 108 | elif ! $CC > /dev/null 2>&1 && |
| 109 | $CC -c -readonly_strings conftest.c > /dev/null 2>&1 && |
| 110 | test -f conftest.o |
| 111 | then |
| 112 | # strings go into readonly segment |
| 113 | CV="-readonly_strings" |
| 114 | |
| 115 | rm conftest.o |
| 116 | if test -n "`${CC-cc} -c $CV conftest.c 2>&1`" ; then |
| 117 | CV="suppressed: string.h" |
| 118 | fi |
| 119 | |
| 120 | dnl C for AIX Compiler |
| 121 | |
| 122 | dnl IRIX C compiler |
| 123 | # -use_readonly_const is the default for IRIX C, |
| 124 | # puts them into .rodata, but they are copied later. |
| 125 | # need to be "-G0 -rdatashared" for strictmode but |
| 126 | # I am not sure what effect that has really. |
| 127 | |
| 128 | fi |
| 129 | rm -f conftest.* |
| 130 | ]) |
| 131 | if test -z "[$]$1" ; then |
| 132 | if test -n "$CV" ; then |
| 133 | case "$CV" in |
| 134 | suppressed*) $1="" ;; # known but suppressed |
| 135 | *) $1="$CV" ;; |
| 136 | esac |
| 137 | fi |
| 138 | fi |
| 139 | AC_SUBST($1) |
| 140 | popdef([CV])dnl |
| 141 | ]) |
| 142 | |
| 143 | |