[PATCH] Properly check linker option in LIBC_LINKER_FEATURE [BZ #28738]

[PATCH] Properly check linker option in LIBC_LINKER_FEATURE [BZ #28738]

[H.J. Lu]

Update LIBC_LINKER_FEATURE to also check linker warning message since
unknown linker -z option may be ignored by linker:

$ touch x.c
$ gcc -shared -Wl,-z,foobar x.c
/usr/bin/ld: warning: -z foobar ignored
$ echo $?
0
$

This fixes BZ #28738.
---
 aclocal.m4 |  8 +++++++-
 configure  | 32 ++++++++++++++++++++++++++++----
 2 files changed, 35 insertions(+), 5 deletions(-)

diff --git a/aclocal.m4 b/aclocal.m4
index 3a90d4f679..3e0bcdd12b 100644
--- a/aclocal.m4
+++ b/aclocal.m4
@@ -236,7 +236,13 @@ EOF
 		    -fPIC -shared -o conftest.so conftest.c
 		    1>&AS_MESSAGE_LOG_FD])
   then
-    libc_linker_feature=yes
+    if ${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS $no_ssp $2 -nostdlib \
+	-nostartfiles -fPIC -shared -o conftest.so conftest.c 2>&1 \
+	| grep "warning: $1 ignored" > /dev/null 2>&1; then
+      true
+    else
+      libc_linker_feature=yes
+    fi
   fi
   rm -f conftest*
 fi
diff --git a/configure b/configure
index 954bae803e..3f956cf777 100755
--- a/configure
+++ b/configure
@@ -6009,7 +6009,13 @@ EOF
   $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
   test $ac_status = 0; }; }
   then
-    libc_linker_feature=yes
+    if ${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS $no_ssp -Wl,-z,execstack -nostdlib \
+	-nostartfiles -fPIC -shared -o conftest.so conftest.c 2>&1 \
+	| grep "warning: -z execstack ignored" > /dev/null 2>&1; then
+      true
+    else
+      libc_linker_feature=yes
+    fi
   fi
   rm -f conftest*
 fi
@@ -6039,7 +6045,13 @@ EOF
   $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
   test $ac_status = 0; }; }
   then
-    libc_linker_feature=yes
+    if ${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS $no_ssp -Wl,-z,start-stop-gc -nostdlib \
+	-nostartfiles -fPIC -shared -o conftest.so conftest.c 2>&1 \
+	| grep "warning: -z start-stop-gc ignored" > /dev/null 2>&1; then
+      true
+    else
+      libc_linker_feature=yes
+    fi
   fi
   rm -f conftest*
 fi
@@ -6070,7 +6082,13 @@ EOF
   $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
   test $ac_status = 0; }; }
   then
-    libc_linker_feature=yes
+    if ${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS $no_ssp -Wl,--depaudit,x -nostdlib \
+	-nostartfiles -fPIC -shared -o conftest.so conftest.c 2>&1 \
+	| grep "warning: --depaudit ignored" > /dev/null 2>&1; then
+      true
+    else
+      libc_linker_feature=yes
+    fi
   fi
   rm -f conftest*
 fi
@@ -6101,7 +6119,13 @@ EOF
   $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
   test $ac_status = 0; }; }
   then
-    libc_linker_feature=yes
+    if ${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS $no_ssp -Wl,--no-dynamic-linker -nostdlib \
+	-nostartfiles -fPIC -shared -o conftest.so conftest.c 2>&1 \
+	| grep "warning: --no-dynamic-linker ignored" > /dev/null 2>&1; then
+      true
+    else
+      libc_linker_feature=yes
+    fi
   fi
   rm -f conftest*
 fi
-- 
2.33.1

Re: [PATCH] Properly check linker option in LIBC_LINKER_FEATURE [BZ #28738]

[Florian Weimer]

* H. J. Lu via Libc-alpha:

> Update LIBC_LINKER_FEATURE to also check linker warning message since
> unknown linker -z option may be ignored by linker:
>
> $ touch x.c
> $ gcc -shared -Wl,-z,foobar x.c
> /usr/bin/ld: warning: -z foobar ignored
> $ echo $?
> 0
> $
>
> This fixes BZ #28738.

Looks okay to me.

Thanks,
Florian

Re: [PATCH] Properly check linker option in LIBC_LINKER_FEATURE [BZ #28738]

[Joseph Myers]

On Sun, 2 Jan 2022, H.J. Lu via Libc-alpha wrote:

> +    if ${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS $no_ssp $2 -nostdlib \
> +	-nostartfiles -fPIC -shared -o conftest.so conftest.c 2>&1 \
> +	| grep "warning: $1 ignored" > /dev/null 2>&1; then

If you check for specific English language text like that (which may not 
be a good idea, since binutils maintainers may expect to be able to 
rephrase messages without breaking glibc), you need to run the linker (and 
thus the compiler) with LC_ALL=C to avoid getting a translated message.

-- 
Joseph S. Myers
joseph@codesourcery.com

[PATCH] Set LC_ALL=C for LIBC_LINKER_FEATURE [BZ #28738]

[H.J. Lu]

[-- Attachment #1: Type: text/plain, Size: 843 bytes --]

On Tue, Jan 4, 2022 at 10:37 AM Joseph Myers <joseph@codesourcery.com> wrote:
>
> On Sun, 2 Jan 2022, H.J. Lu via Libc-alpha wrote:
>
> > +    if ${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS $no_ssp $2 -nostdlib \
> > +     -nostartfiles -fPIC -shared -o conftest.so conftest.c 2>&1 \
> > +     | grep "warning: $1 ignored" > /dev/null 2>&1; then
>
> If you check for specific English language text like that (which may not
> be a good idea, since binutils maintainers may expect to be able to

True.  Different linkers can have different behavior on unknown
options.   We need to update the linker feature check for it.

> rephrase messages without breaking glibc), you need to run the linker (and
> thus the compiler) with LC_ALL=C to avoid getting a translated message.
>

Here is a patch to set LC_ALL=C for LIBC_LINKER_FEATURE.

Thanks.

-- 
H.J.

[-- Attachment #2: 0001-Set-LC_ALL-C-for-LIBC_LINKER_FEATURE-BZ-28738.patch --]
[-- Type: text/x-patch, Size: 2828 bytes --]

From 8f3266ac512e2182c49a42f065bbe97451044ebc Mon Sep 17 00:00:00 2001
From: "H.J. Lu" <hjl.tools@gmail.com>
Date: Tue, 4 Jan 2022 10:40:56 -0800
Subject: [PATCH] Set LC_ALL=C for LIBC_LINKER_FEATURE [BZ #28738]

Set LC_ALL=C when compiling the LIBC_LINKER_FEATURE to avoid linker
warning message translation.

This updates the fix for BZ #28738.
---
 aclocal.m4 | 2 +-
 configure  | 8 ++++----
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/aclocal.m4 b/aclocal.m4
index 3e0bcdd12b..7ee9c53ee8 100644
--- a/aclocal.m4
+++ b/aclocal.m4
@@ -236,7 +236,7 @@ EOF
 		    -fPIC -shared -o conftest.so conftest.c
 		    1>&AS_MESSAGE_LOG_FD])
   then
-    if ${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS $no_ssp $2 -nostdlib \
+    if LC_ALL=C ${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS $no_ssp $2 -nostdlib \
 	-nostartfiles -fPIC -shared -o conftest.so conftest.c 2>&1 \
 	| grep "warning: $1 ignored" > /dev/null 2>&1; then
       true
diff --git a/configure b/configure
index 3f956cf777..a71360abd9 100755
--- a/configure
+++ b/configure
@@ -6009,7 +6009,7 @@ EOF
   $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
   test $ac_status = 0; }; }
   then
-    if ${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS $no_ssp -Wl,-z,execstack -nostdlib \
+    if LC_ALL=C ${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS $no_ssp -Wl,-z,execstack -nostdlib \
 	-nostartfiles -fPIC -shared -o conftest.so conftest.c 2>&1 \
 	| grep "warning: -z execstack ignored" > /dev/null 2>&1; then
       true
@@ -6045,7 +6045,7 @@ EOF
   $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
   test $ac_status = 0; }; }
   then
-    if ${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS $no_ssp -Wl,-z,start-stop-gc -nostdlib \
+    if LC_ALL=C ${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS $no_ssp -Wl,-z,start-stop-gc -nostdlib \
 	-nostartfiles -fPIC -shared -o conftest.so conftest.c 2>&1 \
 	| grep "warning: -z start-stop-gc ignored" > /dev/null 2>&1; then
       true
@@ -6082,7 +6082,7 @@ EOF
   $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
   test $ac_status = 0; }; }
   then
-    if ${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS $no_ssp -Wl,--depaudit,x -nostdlib \
+    if LC_ALL=C ${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS $no_ssp -Wl,--depaudit,x -nostdlib \
 	-nostartfiles -fPIC -shared -o conftest.so conftest.c 2>&1 \
 	| grep "warning: --depaudit ignored" > /dev/null 2>&1; then
       true
@@ -6119,7 +6119,7 @@ EOF
   $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
   test $ac_status = 0; }; }
   then
-    if ${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS $no_ssp -Wl,--no-dynamic-linker -nostdlib \
+    if LC_ALL=C ${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS $no_ssp -Wl,--no-dynamic-linker -nostdlib \
 	-nostartfiles -fPIC -shared -o conftest.so conftest.c 2>&1 \
 	| grep "warning: --no-dynamic-linker ignored" > /dev/null 2>&1; then
       true
-- 
2.33.1

Re: [PATCH] Properly check linker option in LIBC_LINKER_FEATURE [BZ #28738]

[Florian Weimer]

* Joseph Myers:

> On Sun, 2 Jan 2022, H.J. Lu via Libc-alpha wrote:
>
>> +    if ${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS $no_ssp $2 -nostdlib \
>> +	-nostartfiles -fPIC -shared -o conftest.so conftest.c 2>&1 \
>> +	| grep "warning: $1 ignored" > /dev/null 2>&1; then
>
> If you check for specific English language text like that (which may not 
> be a good idea, since binutils maintainers may expect to be able to 
> rephrase messages without breaking glibc), you need to run the linker (and 
> thus the compiler) with LC_ALL=C to avoid getting a translated message.

That was my thought as well, but I think the generated configure script
already takes care of that:

# NLS nuisances.
LC_ALL=C
export LC_ALL
LANGUAGE=C
export LANGUAGE

That's fairly early in the script.

Thanks,
Florian