[PATCH] scripts: Fix fortify checks if compiler does not support _FORTIFY_SOURCE=3

[PATCH] scripts: Fix fortify checks if compiler does not support _FORTIFY_SOURCE=3

[Adhemerval Zanella]

The 30379efad1 added _FORTIFY_SOURCE checks without check if compiler
does support all used fortify levels.  This patch fixes it by first
checking at configure time the maximum support fortify level and using
it instead of a pre-defined one.

Checked on x86_64 with gcc 11, 12, and 13.
---
 Makefile                           |  4 ++--
 Rules                              |  4 ++--
 configure                          | 28 ++++++++++++----------------
 configure.ac                       | 13 +++++++------
 scripts/check-installed-headers.sh | 11 +++++++----
 5 files changed, 30 insertions(+), 30 deletions(-)

diff --git a/Makefile b/Makefile
index f324df7a1f..c6d4817a9e 100644
--- a/Makefile
+++ b/Makefile
@@ -545,7 +545,7 @@ tests-special += $(objpfx)check-installed-headers-c.out
 libof-check-installed-headers-c := testsuite
 $(objpfx)check-installed-headers-c.out: \
     scripts/check-installed-headers.sh $(headers)
-	$(SHELL) $(..)scripts/check-installed-headers.sh c \
+	$(SHELL) $(..)scripts/check-installed-headers.sh c $(supported-fortify) \
 	  "$(CC) $(filter-out -std=%,$(CFLAGS)) -D_ISOMAC $(+includes)" \
 	  $(headers) > $@; \
 	$(evaluate-test)
@@ -555,7 +555,7 @@ tests-special += $(objpfx)check-installed-headers-cxx.out
 libof-check-installed-headers-cxx := testsuite
 $(objpfx)check-installed-headers-cxx.out: \
     scripts/check-installed-headers.sh $(headers)
-	$(SHELL) $(..)scripts/check-installed-headers.sh c++ \
+	$(SHELL) $(..)scripts/check-installed-headers.sh c++ $(supported-fortify) \
 	  "$(CXX) $(filter-out -std=%,$(CXXFLAGS)) -D_ISOMAC $(+includes)" \
 	  $(headers) > $@; \
 	$(evaluate-test)
diff --git a/Rules b/Rules
index 5e945d7347..279ae490ac 100644
--- a/Rules
+++ b/Rules
@@ -85,7 +85,7 @@ tests-special += $(objpfx)check-installed-headers-c.out
 libof-check-installed-headers-c := testsuite
 $(objpfx)check-installed-headers-c.out: \
     $(..)scripts/check-installed-headers.sh $(headers)
-	$(SHELL) $(..)scripts/check-installed-headers.sh c \
+	$(SHELL) $(..)scripts/check-installed-headers.sh c $(supported-fortify) \
 	  "$(CC) $(filter-out -std=%,$(CFLAGS)) -D_ISOMAC $(+includes)" \
 	  $(headers) > $@; \
 	$(evaluate-test)
@@ -97,7 +97,7 @@ tests-special += $(objpfx)check-installed-headers-cxx.out
 libof-check-installed-headers-cxx := testsuite
 $(objpfx)check-installed-headers-cxx.out: \
     $(..)scripts/check-installed-headers.sh $(headers)
-	$(SHELL) $(..)scripts/check-installed-headers.sh c++ \
+	$(SHELL) $(..)scripts/check-installed-headers.sh c++ $(supported-fortify) \
 	  "$(CXX) $(filter-out -std=%,$(CXXFLAGS)) -D_ISOMAC $(+includes)" \
 	  $(headers) > $@; \
 	$(evaluate-test)
diff --git a/configure b/configure
index c02c0b5825..14e2ecce28 100755
--- a/configure
+++ b/configure
@@ -7610,9 +7610,9 @@ fi
 no_fortify_source="-Wp,-U_FORTIFY_SOURCE"
 fortify_source="${no_fortify_source}"
 
-{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for __builtin_dynamic_object_size" >&5
-printf %s "checking for __builtin_dynamic_object_size... " >&6; }
-if test ${libc_cv___builtin_dynamic_object_size+y}
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for maximum supported _FORTIFY_SOURCE level" >&5
+printf %s "checking for maximum supported _FORTIFY_SOURCE level... " >&6; }
+if test ${libc_cv_supported_fortify_source+y}
 then :
   printf %s "(cached) " >&6
 else $as_nop
@@ -7630,30 +7630,24 @@ __builtin_dynamic_object_size("", 0)
 _ACEOF
 if ac_fn_c_try_link "$LINENO"
 then :
-  libc_cv___builtin_dynamic_object_size=yes
-         if test "$enable_fortify_source" = yes
-then :
-  enable_fortify_source=3
-fi
+  libc_cv_supported_fortify_source=3
 else $as_nop
-  libc_cv___builtin_dynamic_object_size=no
-         if test "$enable_fortify_source" = yes
-then :
-  enable_fortify_source=2
-fi
+  libc_cv_supported_fortify_source=2
 fi
 rm -f core conftest.err conftest.$ac_objext conftest.beam \
     conftest$ac_exeext conftest.$ac_ext
 
 fi
-{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $libc_cv___builtin_dynamic_object_size" >&5
-printf "%s\n" "$libc_cv___builtin_dynamic_object_size" >&6; }
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $libc_cv_supported_fortify_source" >&5
+printf "%s\n" "$libc_cv_supported_fortify_source" >&6; }
 
 case $enable_fortify_source in #(
+  yes) :
+    libc_cv_fortify_source=yes enable_fortify_source=$libc_cv_supported_fortify_source ;; #(
   1|2) :
     libc_cv_fortify_source=yes ;; #(
   3) :
-    if test "$libc_cv___builtin_dynamic_object_size" = yes
+    if test $libc_cv_supported_fortify_source = 3
 then :
   libc_cv_fortify_source=yes
 else $as_nop
@@ -7673,6 +7667,8 @@ fi
 
 
 
+config_vars="$config_vars
+supported-fortify = $libc_cv_supported_fortify_source"
 
 { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking whether the assembler requires one version per symbol" >&5
 printf %s "checking whether the assembler requires one version per symbol... " >&6; }
diff --git a/configure.ac b/configure.ac
index 09553541fb..ff35bf4d6b 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1578,17 +1578,17 @@ dnl support it
 no_fortify_source="-Wp,-U_FORTIFY_SOURCE"
 fortify_source="${no_fortify_source}"
 
-AC_CACHE_CHECK([for __builtin_dynamic_object_size], [libc_cv___builtin_dynamic_object_size], [
+AC_CACHE_CHECK([for maximum supported _FORTIFY_SOURCE level],
+	       [libc_cv_supported_fortify_source], [
     AC_LINK_IFELSE([AC_LANG_PROGRAM([], [__builtin_dynamic_object_size("", 0)])],
-        [libc_cv___builtin_dynamic_object_size=yes
-         AS_IF([test "$enable_fortify_source" = yes], [enable_fortify_source=3])],
-        [libc_cv___builtin_dynamic_object_size=no
-         AS_IF([test "$enable_fortify_source" = yes], [enable_fortify_source=2])])
+        [libc_cv_supported_fortify_source=3],
+        [libc_cv_supported_fortify_source=2])
 ])
 
 AS_CASE([$enable_fortify_source],
+        [yes], [libc_cv_fortify_source=yes enable_fortify_source=$libc_cv_supported_fortify_source],
         [1|2], [libc_cv_fortify_source=yes],
-        [3], [AS_IF([test "$libc_cv___builtin_dynamic_object_size" = yes],
+        [3], [AS_IF([test $libc_cv_supported_fortify_source = 3],
                     [libc_cv_fortify_source=yes],
                     [AC_MSG_ERROR([Compiler doesn't provide necessary support for _FORTIFY_SOURCE=3])])],
         [libc_cv_fortify_source=no])
@@ -1601,6 +1601,7 @@ AC_SUBST(enable_fortify_source)
 AC_SUBST(libc_cv_fortify_source)
 AC_SUBST(no_fortify_source)
 AC_SUBST(fortify_source)
+LIBC_CONFIG_VAR([supported-fortify], [$libc_cv_supported_fortify_source])
 
 dnl Starting with binutils 2.35, GAS can attach multiple symbol versions
 dnl to one symbol (PR 23840).
diff --git a/scripts/check-installed-headers.sh b/scripts/check-installed-headers.sh
index 23506a2514..ee9f534ab0 100644
--- a/scripts/check-installed-headers.sh
+++ b/scripts/check-installed-headers.sh
@@ -29,11 +29,12 @@ cxx_modes="-std=c++98 -std=gnu++98 -std=c++11 -std=gnu++11"
 # These are probably the most commonly used three.
 lib_modes="-D_DEFAULT_SOURCE=1 -D_GNU_SOURCE=1 -D_XOPEN_SOURCE=700"
 
-# Also check for fortify modes, since it might be enabled as default.
-fortify_modes="1 2 3"
+# Also check for fortify modes, since it might be enabled as default.  The
+# maximum value to be checked is define by maximum_fortify argument.
+fortify_modes=""
 
 if [ $# -lt 3 ]; then
-    echo "usage: $0 c|c++ \"compile command\" header header header..." >&2
+    echo "usage: $0 c|c++ maximum_fortify \"compile command\" header header header..." >&2
     exit 2
 fi
 case "$1" in
@@ -50,6 +51,8 @@ case "$1" in
         exit 2;;
 esac
 shift
+fortify_modes=$(seq -s' ' 1 $1)
+shift
 cc_cmd="$1"
 shift
 trap "rm -f '$cih_test_c'" 0
@@ -104,7 +107,6 @@ EOF
     for lang_mode in "" $lang_modes; do
         for lib_mode in "" $lib_modes; do
             for fortify_mode in "" $fortify_modes; do
-                echo :::: $lang_mode $lib_mode $fortify_mode
                 if [ -z "$lib_mode" ]; then
                     expanded_lib_mode='/* default library mode */'
                 else
@@ -114,6 +116,7 @@ EOF
                 if [ ! -z $fortify_mode ]; then
                     fortify_mode="#define _FORTIFY_SOURCE $fortify_mode"
                 fi
+                echo :::: $lang_mode $lib_mode $fortify_mode
                 cat >"$cih_test_c" <<EOF
 /* These macros may have been defined on the command line.  They are
    inappropriate for this test.  */
-- 
2.34.1

Re: [PATCH] scripts: Fix fortify checks if compiler does not support _FORTIFY_SOURCE=3

[Siddhesh Poyarekar]

On 2023-07-20 10:40, Adhemerval Zanella via Libc-alpha wrote:
> The 30379efad1 added _FORTIFY_SOURCE checks without check if compiler
> does support all used fortify levels.  This patch fixes it by first
> checking at configure time the maximum support fortify level and using
> it instead of a pre-defined one.
> 
> Checked on x86_64 with gcc 11, 12, and 13.
> ---

LGTM, pending approval from RM.  At the moment there's no real reason to 
verify headers for different fortification levels (just 1 or 2 would do) 
but I reckon it's a future-proof change, in case we ever end up 
diverging further on those levels.

Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>

Thanks,
Sid


>   Makefile                           |  4 ++--
>   Rules                              |  4 ++--
>   configure                          | 28 ++++++++++++----------------
>   configure.ac                       | 13 +++++++------
>   scripts/check-installed-headers.sh | 11 +++++++----
>   5 files changed, 30 insertions(+), 30 deletions(-)
> 
> diff --git a/Makefile b/Makefile
> index f324df7a1f..c6d4817a9e 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -545,7 +545,7 @@ tests-special += $(objpfx)check-installed-headers-c.out
>   libof-check-installed-headers-c := testsuite
>   $(objpfx)check-installed-headers-c.out: \
>       scripts/check-installed-headers.sh $(headers)
> -	$(SHELL) $(..)scripts/check-installed-headers.sh c \
> +	$(SHELL) $(..)scripts/check-installed-headers.sh c $(supported-fortify) \
>   	  "$(CC) $(filter-out -std=%,$(CFLAGS)) -D_ISOMAC $(+includes)" \
>   	  $(headers) > $@; \
>   	$(evaluate-test)
> @@ -555,7 +555,7 @@ tests-special += $(objpfx)check-installed-headers-cxx.out
>   libof-check-installed-headers-cxx := testsuite
>   $(objpfx)check-installed-headers-cxx.out: \
>       scripts/check-installed-headers.sh $(headers)
> -	$(SHELL) $(..)scripts/check-installed-headers.sh c++ \
> +	$(SHELL) $(..)scripts/check-installed-headers.sh c++ $(supported-fortify) \
>   	  "$(CXX) $(filter-out -std=%,$(CXXFLAGS)) -D_ISOMAC $(+includes)" \
>   	  $(headers) > $@; \
>   	$(evaluate-test)
> diff --git a/Rules b/Rules
> index 5e945d7347..279ae490ac 100644
> --- a/Rules
> +++ b/Rules
> @@ -85,7 +85,7 @@ tests-special += $(objpfx)check-installed-headers-c.out
>   libof-check-installed-headers-c := testsuite
>   $(objpfx)check-installed-headers-c.out: \
>       $(..)scripts/check-installed-headers.sh $(headers)
> -	$(SHELL) $(..)scripts/check-installed-headers.sh c \
> +	$(SHELL) $(..)scripts/check-installed-headers.sh c $(supported-fortify) \
>   	  "$(CC) $(filter-out -std=%,$(CFLAGS)) -D_ISOMAC $(+includes)" \
>   	  $(headers) > $@; \
>   	$(evaluate-test)
> @@ -97,7 +97,7 @@ tests-special += $(objpfx)check-installed-headers-cxx.out
>   libof-check-installed-headers-cxx := testsuite
>   $(objpfx)check-installed-headers-cxx.out: \
>       $(..)scripts/check-installed-headers.sh $(headers)
> -	$(SHELL) $(..)scripts/check-installed-headers.sh c++ \
> +	$(SHELL) $(..)scripts/check-installed-headers.sh c++ $(supported-fortify) \
>   	  "$(CXX) $(filter-out -std=%,$(CXXFLAGS)) -D_ISOMAC $(+includes)" \
>   	  $(headers) > $@; \
>   	$(evaluate-test)
> diff --git a/configure b/configure
> index c02c0b5825..14e2ecce28 100755
> --- a/configure
> +++ b/configure
> @@ -7610,9 +7610,9 @@ fi
>   no_fortify_source="-Wp,-U_FORTIFY_SOURCE"
>   fortify_source="${no_fortify_source}"
>   
> -{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for __builtin_dynamic_object_size" >&5
> -printf %s "checking for __builtin_dynamic_object_size... " >&6; }
> -if test ${libc_cv___builtin_dynamic_object_size+y}
> +{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for maximum supported _FORTIFY_SOURCE level" >&5
> +printf %s "checking for maximum supported _FORTIFY_SOURCE level... " >&6; }
> +if test ${libc_cv_supported_fortify_source+y}
>   then :
>     printf %s "(cached) " >&6
>   else $as_nop
> @@ -7630,30 +7630,24 @@ __builtin_dynamic_object_size("", 0)
>   _ACEOF
>   if ac_fn_c_try_link "$LINENO"
>   then :
> -  libc_cv___builtin_dynamic_object_size=yes
> -         if test "$enable_fortify_source" = yes
> -then :
> -  enable_fortify_source=3
> -fi
> +  libc_cv_supported_fortify_source=3
>   else $as_nop
> -  libc_cv___builtin_dynamic_object_size=no
> -         if test "$enable_fortify_source" = yes
> -then :
> -  enable_fortify_source=2
> -fi
> +  libc_cv_supported_fortify_source=2
>   fi
>   rm -f core conftest.err conftest.$ac_objext conftest.beam \
>       conftest$ac_exeext conftest.$ac_ext
>   
>   fi
> -{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $libc_cv___builtin_dynamic_object_size" >&5
> -printf "%s\n" "$libc_cv___builtin_dynamic_object_size" >&6; }
> +{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $libc_cv_supported_fortify_source" >&5
> +printf "%s\n" "$libc_cv_supported_fortify_source" >&6; }
>   
>   case $enable_fortify_source in #(
> +  yes) :
> +    libc_cv_fortify_source=yes enable_fortify_source=$libc_cv_supported_fortify_source ;; #(
>     1|2) :
>       libc_cv_fortify_source=yes ;; #(
>     3) :
> -    if test "$libc_cv___builtin_dynamic_object_size" = yes
> +    if test $libc_cv_supported_fortify_source = 3
>   then :
>     libc_cv_fortify_source=yes
>   else $as_nop
> @@ -7673,6 +7667,8 @@ fi
>   
>   
>   
> +config_vars="$config_vars
> +supported-fortify = $libc_cv_supported_fortify_source"
>   
>   { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking whether the assembler requires one version per symbol" >&5
>   printf %s "checking whether the assembler requires one version per symbol... " >&6; }
> diff --git a/configure.ac b/configure.ac
> index 09553541fb..ff35bf4d6b 100644
> --- a/configure.ac
> +++ b/configure.ac
> @@ -1578,17 +1578,17 @@ dnl support it
>   no_fortify_source="-Wp,-U_FORTIFY_SOURCE"
>   fortify_source="${no_fortify_source}"
>   
> -AC_CACHE_CHECK([for __builtin_dynamic_object_size], [libc_cv___builtin_dynamic_object_size], [
> +AC_CACHE_CHECK([for maximum supported _FORTIFY_SOURCE level],
> +	       [libc_cv_supported_fortify_source], [
>       AC_LINK_IFELSE([AC_LANG_PROGRAM([], [__builtin_dynamic_object_size("", 0)])],
> -        [libc_cv___builtin_dynamic_object_size=yes
> -         AS_IF([test "$enable_fortify_source" = yes], [enable_fortify_source=3])],
> -        [libc_cv___builtin_dynamic_object_size=no
> -         AS_IF([test "$enable_fortify_source" = yes], [enable_fortify_source=2])])
> +        [libc_cv_supported_fortify_source=3],
> +        [libc_cv_supported_fortify_source=2])
>   ])
>   
>   AS_CASE([$enable_fortify_source],
> +        [yes], [libc_cv_fortify_source=yes enable_fortify_source=$libc_cv_supported_fortify_source],
>           [1|2], [libc_cv_fortify_source=yes],
> -        [3], [AS_IF([test "$libc_cv___builtin_dynamic_object_size" = yes],
> +        [3], [AS_IF([test $libc_cv_supported_fortify_source = 3],
>                       [libc_cv_fortify_source=yes],
>                       [AC_MSG_ERROR([Compiler doesn't provide necessary support for _FORTIFY_SOURCE=3])])],
>           [libc_cv_fortify_source=no])
> @@ -1601,6 +1601,7 @@ AC_SUBST(enable_fortify_source)
>   AC_SUBST(libc_cv_fortify_source)
>   AC_SUBST(no_fortify_source)
>   AC_SUBST(fortify_source)
> +LIBC_CONFIG_VAR([supported-fortify], [$libc_cv_supported_fortify_source])
>   
>   dnl Starting with binutils 2.35, GAS can attach multiple symbol versions
>   dnl to one symbol (PR 23840).
> diff --git a/scripts/check-installed-headers.sh b/scripts/check-installed-headers.sh
> index 23506a2514..ee9f534ab0 100644
> --- a/scripts/check-installed-headers.sh
> +++ b/scripts/check-installed-headers.sh
> @@ -29,11 +29,12 @@ cxx_modes="-std=c++98 -std=gnu++98 -std=c++11 -std=gnu++11"
>   # These are probably the most commonly used three.
>   lib_modes="-D_DEFAULT_SOURCE=1 -D_GNU_SOURCE=1 -D_XOPEN_SOURCE=700"
>   
> -# Also check for fortify modes, since it might be enabled as default.
> -fortify_modes="1 2 3"
> +# Also check for fortify modes, since it might be enabled as default.  The
> +# maximum value to be checked is define by maximum_fortify argument.
> +fortify_modes=""
>   
>   if [ $# -lt 3 ]; then
> -    echo "usage: $0 c|c++ \"compile command\" header header header..." >&2
> +    echo "usage: $0 c|c++ maximum_fortify \"compile command\" header header header..." >&2
>       exit 2
>   fi
>   case "$1" in
> @@ -50,6 +51,8 @@ case "$1" in
>           exit 2;;
>   esac
>   shift
> +fortify_modes=$(seq -s' ' 1 $1)
> +shift
>   cc_cmd="$1"
>   shift
>   trap "rm -f '$cih_test_c'" 0
> @@ -104,7 +107,6 @@ EOF
>       for lang_mode in "" $lang_modes; do
>           for lib_mode in "" $lib_modes; do
>               for fortify_mode in "" $fortify_modes; do
> -                echo :::: $lang_mode $lib_mode $fortify_mode
>                   if [ -z "$lib_mode" ]; then
>                       expanded_lib_mode='/* default library mode */'
>                   else
> @@ -114,6 +116,7 @@ EOF
>                   if [ ! -z $fortify_mode ]; then
>                       fortify_mode="#define _FORTIFY_SOURCE $fortify_mode"
>                   fi
> +                echo :::: $lang_mode $lib_mode $fortify_mode
>                   cat >"$cih_test_c" <<EOF
>   /* These macros may have been defined on the command line.  They are
>      inappropriate for this test.  */

Re: [PATCH] scripts: Fix fortify checks if compiler does not support _FORTIFY_SOURCE=3

[Florian Weimer]

* Siddhesh Poyarekar:

> On 2023-07-20 10:40, Adhemerval Zanella via Libc-alpha wrote:
>> The 30379efad1 added _FORTIFY_SOURCE checks without check if compiler
>> does support all used fortify levels.  This patch fixes it by first
>> checking at configure time the maximum support fortify level and using
>> it instead of a pre-defined one.
>> Checked on x86_64 with gcc 11, 12, and 13.
>> ---
>
> LGTM, pending approval from RM.  At the moment there's no real reason
> to verify headers for different fortification levels (just 1 or 2
> would do) but I reckon it's a future-proof change, in case we ever end
> up diverging further on those levels.
>
> Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>

Agreed, and (with GCC 11):

Tested-by: Florian Weimer <fweimer@redhat.com>

Thanks,
Florian

Re: [PATCH] scripts: Fix fortify checks if compiler does not support _FORTIFY_SOURCE=3

[Andreas K. Huettel]

[-- Attachment #1: Type: text/plain, Size: 1209 bytes --]

Am Donnerstag, 20. Juli 2023, 18:26:53 CEST schrieb Florian Weimer:
> * Siddhesh Poyarekar:
> 
> > On 2023-07-20 10:40, Adhemerval Zanella via Libc-alpha wrote:
> >> The 30379efad1 added _FORTIFY_SOURCE checks without check if compiler
> >> does support all used fortify levels.  This patch fixes it by first
> >> checking at configure time the maximum support fortify level and using
> >> it instead of a pre-defined one.
> >> Checked on x86_64 with gcc 11, 12, and 13.
> >> ---
> >
> > LGTM, pending approval from RM.  At the moment there's no real reason
> > to verify headers for different fortification levels (just 1 or 2
> > would do) but I reckon it's a future-proof change, in case we ever end
> > up diverging further on those levels.
> >
> > Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
> 
> Agreed, and (with GCC 11):
> 
> Tested-by: Florian Weimer <fweimer@redhat.com>
> 

OK let's go with it. Thanks! -a

-- 
PD Dr. Andreas K. Huettel
Institute for Experimental and Applied Physics
University of Regensburg
93040 Regensburg
Germany

tel. +49 151 241 67748 (mobile)
tel. +49 941 943 1618 (office)
e-mail andreas.huettel@ur.de
https://www.akhuettel.de/
https://www.akhuettel.de/group/

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