[PATCH v2] lib: fix multiple strlcpy definition

Some C libraries, like uClibc and musl, provide BSD compatible
strlcpy(). Add check_strlcpy() to configure, and avoid defining strlcpy
and strlcat when the C library provides them.

This fixes the following static link error with uClibc-ng:

.../sysroot/usr/lib/libc.a(strlcpy.os): In function `strlcpy':
strlcpy.c:(.text+0x0): multiple definition of `strlcpy'
../lib/libutil.a(utils.o):utils.c:(.text+0x1ddc): first defined here
collect2: error: ld returned 1 exit status

Acked-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
---
v2: Fix the order of strlcpy parameters
---
 configure    | 24 ++++++++++++++++++++++++
 lib/Makefile |  4 ++++
 lib/utils.c  |  2 ++
 3 files changed, 30 insertions(+)

diff --git a/configure b/configure
index 7be8fb113cc9..e0982f34a992 100755
--- a/configure
+++ b/configure

@@ -326,6 +326,27 @@ EOF
     rm -f $TMPDIR/dbtest.c $TMPDIR/dbtest
 }
 
+check_strlcpy()
+{
+    cat >$TMPDIR/strtest.c <<EOF
+#include <string.h>
+int main(int argc, char **argv) {
+	char dst[10];
+	strlcpy(dst, "test", sizeof(dst));
+	return 0;
+}
+EOF
+    $CC -I$INCLUDE -o $TMPDIR/strtest $TMPDIR/strtest.c >/dev/null 2>&1
+    if [ $? -eq 0 ]
+    then
+	echo "no"
+    else
+	echo "NEED_STRLCPY:=y" >>$CONFIG
+	echo "yes"
+    fi
+    rm -f $TMPDIR/strtest.c $TMPDIR/strtest
+}
+
 quiet_config()
 {
 	cat <<EOF

@@ -397,6 +418,9 @@ check_mnl
 echo -n "Berkeley DB: "
 check_berkeley_db
 
+echo -n "need for strlcpy: "
+check_strlcpy
+
 echo
 echo -n "docs:"
 check_docs

diff --git a/lib/Makefile b/lib/Makefile
index 0fbdf4c31f50..132ad00c3335 100644
--- a/lib/Makefile
+++ b/lib/Makefile

@@ -1,5 +1,9 @@
 include ../config.mk
 
+ifeq ($(NEED_STRLCPY),y)
+	CFLAGS += -DNEED_STRLCPY
+endif
+
 CFLAGS += -fPIC
 
 UTILOBJ = utils.o rt_names.o ll_types.o ll_proto.o ll_addr.o \

diff --git a/lib/utils.c b/lib/utils.c
index bbd3cbc46a0e..240e7426a810 100644
--- a/lib/utils.c
+++ b/lib/utils.c

@@ -1231,6 +1231,7 @@ int get_real_family(int rtm_type, int rtm_family)
 	return rtm_family;
 }
 
+#ifdef NEED_STRLCPY
 size_t strlcpy(char *dst, const char *src, size_t size)
 {
 	size_t srclen = strlen(src);

@@ -1253,3 +1254,4 @@ size_t strlcat(char *dst, const char *src, size_t size)
 
 	return dlen + strlcpy(dst + dlen, src, size - dlen);
 }
+#endif

-- 
2.14.2

On Thu, 28 Sep 2017 21:02:11 +0300
Baruch Siach [off-list ref] wrote:

Some C libraries, like uClibc and musl, provide BSD compatible
strlcpy(). Add check_strlcpy() to configure, and avoid defining strlcpy
and strlcat when the C library provides them.

This fixes the following static link error with uClibc-ng:

.../sysroot/usr/lib/libc.a(strlcpy.os): In function `strlcpy':
strlcpy.c:(.text+0x0): multiple definition of `strlcpy'
../lib/libutil.a(utils.o):utils.c:(.text+0x1ddc): first defined here
collect2: error: ld returned 1 exit status

Acked-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Baruch Siach <baruch@tkos.co.il>

This is OK because it doesn't impact normal glibc too much.

I just removed all the conditional CFLAGS out of subdirectory Makefiles
and moved them into the generated config.mk. Please do that for this
as well and resubmit.

Hi Stephen,

On Fri, Sep 29, 2017 at 11:58:58AM -0700, Stephen Hemminger wrote:

On Thu, 28 Sep 2017 21:02:11 +0300
Baruch Siach [off-list ref] wrote:

quoted

Some C libraries, like uClibc and musl, provide BSD compatible
strlcpy(). Add check_strlcpy() to configure, and avoid defining strlcpy
and strlcat when the C library provides them.

This fixes the following static link error with uClibc-ng:

.../sysroot/usr/lib/libc.a(strlcpy.os): In function `strlcpy':
strlcpy.c:(.text+0x0): multiple definition of `strlcpy'
../lib/libutil.a(utils.o):utils.c:(.text+0x1ddc): first defined here
collect2: error: ld returned 1 exit status

Acked-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Baruch Siach <baruch@tkos.co.il>

This is OK because it doesn't impact normal glibc too much.

quoted

diff --git a/lib/Makefile b/lib/Makefile
index 0fbdf4c31f50..132ad00c3335 100644
--- a/lib/Makefile
+++ b/lib/Makefile

@@ -1,5 +1,9 @@
 include ../config.mk
 
+ifeq ($(NEED_STRLCPY),y)
+	CFLAGS += -DNEED_STRLCPY
+endif
+

I just removed all the conditional CFLAGS out of subdirectory Makefiles
and moved them into the generated config.mk. Please do that for this
as well and resubmit.

What code do you refer to? I don't see that as of current master 
(e4139268ba96).

baruch

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