[syslog-ng] linking changes

[Corinna Vinschen]

On Feb 23 16:09, Balazs Scheidler wrote:
> Before making a fool from myself, can you please check if this patch is
> OK, before commit & push? (against the current HEAD).
> 
> My intention was:
>   * create a static lib for linking with programs (unit tests & pdbtool)
>   * recompile each source files as a part of the shared library
> separately
> 
> This way:
>   * no linking of static lib into shared lib happens
> 
> Also, a heads up: this will be a problem again in syslog-ng OSE 3.3,
> where I started to embed dependent libraries into the syslog-ng tree
> (ivykis, libmongo-client) because those are not yet in widespread use.
> That's implemented using static libraries and -fPIC, and I don't see an
> easy solution for that problem, unless of course one obtains and
> installs those libraries separately.

ivykis and libmongo-client are not available for Cygwin.  Is there
no way around using these libs by using conditional compilation?

If that's not feasible for some reason, could you please at least allow
to disable affected modules from building so that not the entire build
fails just because some modules won't work on some systems?

> $ git diff
> diff --git a/modules/dbparser/Makefile.am b/modules/dbparser/Makefile.am
> index b2ab700..7e4c366 100644
> --- a/modules/dbparser/Makefile.am
> +++ b/modules/dbparser/Makefile.am
> @@ -11,26 +11,30 @@ AM_CPPFLAGS = -I$(top_srcdir)/lib -I../../lib
>  AM_CFLAGS = @CFLAGS_NOWARN_POINTER_SIGN@
>  export top_srcdir
>  
> -lib_LIBRARIES = libsyslog-ng-patterndb.a
> +noinst_LIBRARIES = libsyslog-ng-patterndb.a
>  libsyslog_ng_patterndb_a_SOURCES = radix.c radix.h \
>         patterndb.c patterndb.h patterndb-int.h \
>         timerwheel.c timerwheel.h \
>         patternize.c patternize.h
> -libsyslog_ng_patterndb_a_CFLAGS = $(AM_CFLAGS) -fPIC
>  
> +# we're not linking against the .a file as this is not supported on Cygwin,
> +# even if we compile it using -fPIC.  Therefore the .a file is only used to
> +# link programs, and the dbparser.so gets those files as source files,
> +# thereby recompiling them twice.
>  module_LTLIBRARIES = libdbparser.la
>  libdbparser_la_SOURCES = \
>         dbparser.c dbparser.h \
> -       dbparser-grammar.y dbparser-parser.c dbparser-parser.h dbparser-plugin.c
> +       dbparser-grammar.y dbparser-parser.c dbparser-parser.h dbparser-plugin.c \
> +       $(libsyslog_ng_patterndb_a_SOURCES)
>  
>  libdbparser_la_CPPFLAGS = $(AM_CPPFLAGS)
> -libdbparser_la_LIBADD = ../../lib/libsyslog-ng.la libsyslog-ng-patterndb.a
> +libdbparser_la_LIBADD = ../../lib/libsyslog-ng.la

This fails to build on Cygwin because libdbparser_la_LIBADD is missing a
@OPENSSL_LIBS@ (needed by patternize.c).

Amazing but true: Another restriction of the Windows platform is the
inability to create shared libs with undefined symbols.  All symbols must
be resolvable at link time.

>  libdbparser_la_LDFLAGS = -avoid-version -module -no-undefined
>  
>  bin_PROGRAMS = pdbtool
>  pdbtool_SOURCES = pdbtool.c
>  pdbtool_CPPFLAGS = $(AM_CPPFLAGS) @OPENSSL_CFLAGS@
> -pdbtool_LDADD = ../../lib/libsyslog-ng.la libsyslog-ng-patterndb.a @TOOL_DEPS_LIBS@ @OPENSSL_LIBS@
> +pdbtool_LDADD =  libsyslog-ng-patterndb.a ../../lib/libsyslog-ng.la @TOOL_DEPS_LIBS@ @OPENSSL_LIBS@
>  
>  BUILT_SOURCES = dbparser-grammar.y dbparser-grammar.c dbparser-grammar.h
>  EXTRA_DIST = $(BUILT_SOURCES) radix-find.c dbparser-grammar.ym
> diff --git a/modules/dbparser/tests/Makefile.am b/modules/dbparser/tests/Makefile.am
> index 8d3a970..6726121 100644
> --- a/modules/dbparser/tests/Makefile.am
> +++ b/modules/dbparser/tests/Makefile.am
> @@ -1,6 +1,6 @@
>  AM_CFLAGS = -I$(top_srcdir)/lib -I../../../lib -I$(top_srcdir)/modules/dbparser -I.. @CFLAGS_NOWARN_POINTER_SIGN@
>  AM_LDFLAGS = -dlpreopen ../../syslogformat/libsyslogformat.la
> -LDADD = $(top_builddir)/lib/libsyslog-ng.la ../libsyslog-ng-patterndb.a  ../patternize.lo @TOOL_DEPS_LIBS@ @OPENSSL_LIBS@
> +LDADD = $(top_builddir)/lib/libsyslog-ng.la ../libsyslog-ng-patterndb.a @TOOL_DEPS_LIBS@ @OPENSSL_LIBS@

I didn't test that, but shouldn't this LDADD be reordered as well, just
as in the pdbtool_LDADD case?

  LDADD = ../libsyslog-ng-patterndb.a $(top_builddir)/lib/libsyslog-ng.la @TOOL_DEPS_LIBS@ @OPENSSL_LIBS@

Btw., I'm seeing a lot of

  foo.y: warning: X nonterminals useless in grammar
  foo.y: warning: Y rules useless in grammar

messages.  Aren't the grep calls in build/lex-rules.am wrong?

  grep -E -v "warning: (nonterminals|rules) useless in grammar

instead of 

  grep -E -v "warning: (nonterminal|rule) useless in grammar

?  Or does the message depend on the version of yacc/bison used, perhaps?


Thanks,
Corinna

-- 
Corinna Vinschen
Cygwin Project Co-Leader
Red Hat