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List:       ipsec-tools-devel
Subject:    [Ipsec-tools-devel] Link failure with libfl shared library
From:       Paul Barker <paul () paulbarker ! me ! uk>
Date:       2014-03-11 19:15:04
Message-ID: CANyK_8ewmxGA3vBVJW6s1APXPmxPR+DFWZ61EL8pCt288aKQ6w () mail ! gmail ! com
[Download RAW message or body]

Hi all,

I'm getting link failures against libfl.so (the flex library) which
weren't present when only libfl.a had been built. libfl only provides
two functions, a main function which just calls yylex and a dummy
yywrap function which always returns 1. That causes a link problem as
ld is looking for the symbol 'yylex' after it has read libfl.so and
can't find it.

Of the 4 flex source files in ipsec-tools, 1 overrides yywrap and one
contains "%option noyywrap" to disable calls to yywrap. I think it's
safe to add "%option noyywrap" to the other two flex source files as
they're using the default yywrap function from libfl which does
nothing.

Once these two files have that option, there are no further references
to yywrap and we don't have to link against libfl any more. So
"$(LEXLIB)" is removed from *_LDADD in the various Makefile.am files.
That solves the link failure.

I've attached a patch against version 0.8.1 (also applies cleanly to
0.8.2) to implement these changes. Please could you review it for
merging into ipsec-tools. If the patch needs re-creating against a
more recent version of ipsec-tools please let me know.

Thanks,

-- 
Paul Barker

Email: paul@paulbarker.me.uk
http://www.paulbarker.me.uk

["0002-Don-t-link-against-libfl.patch" (text/x-patch)]

From e48b9097dce7bc2bfbb9e9c542124d3b5cebab39 Mon Sep 17 00:00:00 2001
From: Paul Barker <paul@paulbarker.me.uk>
Date: Wed, 5 Mar 2014 13:39:14 +0000
Subject: [PATCH] Don't link against libfl

We can remove all references to yywrap by adding "%option noyywrap" statements
to each flex source file that doesn't override yywrap. After this, we no longer
need to link against libfl and so no longer get errors about undefined
references to yylex.

Signed-off-by: Paul Barker <paul@paulbarker.me.uk>
Upstream-status: Pending
---
 src/libipsec/Makefile.am | 1 -
 src/racoon/Makefile.am   | 2 +-
 src/racoon/cftoken.l     | 2 ++
 src/setkey/Makefile.am   | 1 -
 src/setkey/token.l       | 2 ++
 5 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/src/libipsec/Makefile.am b/src/libipsec/Makefile.am
index 6a4e3b3..df1e106 100644
--- a/src/libipsec/Makefile.am
+++ b/src/libipsec/Makefile.am
@@ -26,7 +26,6 @@ libipsec_la_SOURCES = \
 # version is current:revision:age.
 # See: http://www.gnu.org/manual/libtool-1.4.2/html_chapter/libtool_6.html#SEC32
 libipsec_la_LDFLAGS = -version-info 0:1:0
-libipsec_la_LIBADD = $(LEXLIB)
 
 noinst_HEADERS = ipsec_strerror.h
 
diff --git a/src/racoon/Makefile.am b/src/racoon/Makefile.am
index dbaded9..0662957 100644
--- a/src/racoon/Makefile.am
+++ b/src/racoon/Makefile.am
@@ -38,7 +38,7 @@ racoon_SOURCES = \
 	cftoken.l cfparse.y prsa_tok.l prsa_par.y 
 EXTRA_racoon_SOURCES = isakmp_xauth.c isakmp_cfg.c isakmp_unity.c throttle.c \
 	isakmp_frag.c nattraversal.c security.c $(MISSING_ALGOS)
-racoon_LDADD = $(CRYPTOBJS) $(HYBRID_OBJS) $(NATT_OBJS) $(FRAG_OBJS) $(LEXLIB) \
+racoon_LDADD = $(CRYPTOBJS) $(HYBRID_OBJS) $(NATT_OBJS) $(FRAG_OBJS) \
 	 $(SECCTX_OBJS) vmbuf.o sockmisc.o misc.o ../libipsec/libipsec.la
 racoon_DEPENDENCIES = \
 	$(CRYPTOBJS) $(HYBRID_OBJS) $(NATT_OBJS) $(FRAG_OBJS) $(SECCTX_OBJS) \
diff --git a/src/racoon/cftoken.l b/src/racoon/cftoken.l
index 490242c..1701922 100644
--- a/src/racoon/cftoken.l
+++ b/src/racoon/cftoken.l
@@ -106,6 +106,8 @@ static int incstackp = 0;
 static int yy_first_time = 1;
 %}
 
+%option noyywrap
+
 /* common seciton */
 nl		\n
 ws		[ \t]+
diff --git a/src/setkey/Makefile.am b/src/setkey/Makefile.am
index 746c1f1..389e6cf 100644
--- a/src/setkey/Makefile.am
+++ b/src/setkey/Makefile.am
@@ -13,7 +13,6 @@ setkey_SOURCES = \
 
 setkey_LDFLAGS = ../libipsec/libipsec.la
 setkey_DEPENDENCIES = ../libipsec/libipsec.la
-setkey_LDADD = $(LEXLIB)
 
 noinst_HEADERS = vchar.h extern.h
 man8_MANS = setkey.8
diff --git a/src/setkey/token.l b/src/setkey/token.l
index ad3d843..eb23b76 100644
--- a/src/setkey/token.l
+++ b/src/setkey/token.l
@@ -88,6 +88,8 @@
 #endif
 %}
 
+%option noyywrap
+
 /* common section */
 nl		\n
 ws		[ \t]+
-- 
1.9.0



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