Re: [PATCH] Fix libnl/libnl-3 logic in configure script

On Mon, Jan 06, 2014 at 11:08:37AM -0600, Ryan O'Hara wrote:
> This patch causes the configure script to prefer libnl-3 over
> libnl(1). The configure script will first check for libnl-3 and
> libnl-genl-3. If both are found, use them. If not, check for
> libnl(1). This is useful when building on systems that have both
> libnl-3 and libnl(1) installed. It also fixes some redundant libraries
> in LIBS.

By the way, there is probably a better way to do this. I know that
AC_CHECK_LIB will add -l<lib> to LIBS automatically and set a
variable, but this is a quick fix.

Also note that it might be possible to simply check for libnl-genl-3
since it requires libnl-3. For now, check for both.

I will submit a pull request over on github with an udpated configure
script.

Ryan

> ---
>  configure.in | 32 ++++++++++++++++----------------
>  1 file changed, 16 insertions(+), 16 deletions(-)
> 
> diff --git a/configure.in b/configure.in
> index 3daf3ee..7f3eef1 100644
> --- a/configure.in
> +++ b/configure.in
> @@ -55,30 +55,30 @@ dnl ----[ Checks for libraries ]----
>  AC_CHECK_LIB(crypt, crypt,,AC_MSG_ERROR([crypt() function is required]))
>  AC_CHECK_LIB(crypto, MD5_Init,,AC_MSG_ERROR([OpenSSL libraries are required]))
>  AC_CHECK_LIB(ssl, SSL_CTX_new,,AC_MSG_ERROR([OpenSSL libraries are required]))
> -AC_CHECK_LIB(nl, nl_socket_modify_cb,
> +
> +AC_CHECK_LIB(nl-3, nl_socket_alloc,
>    [
> -    USE_NL="LIBIPVS_USE_NL"
> -    CFLAGS="$CFLAGS -DFALLBACK_LIBNL1"
> -    LIBS="$LIBS -lnl"
> +    AC_CHECK_LIB(nl-genl-3, genl_connect,
> +      [
> +        USE_NL="LIBIPVS_USE_NL"
> +        CFLAGS="$CFLAGS $(pkg-config libnl-genl-3.0)"
> +	LIBS="$LIBS $(pkg-config --libs libnl-genl-3.0)"
> +      ],
> +      [
> +        AC_MSG_ERROR([libnl-3 is installed but not libnl-gen-3. Please, install libnl-gen-3.])
> +      ]),
>    ],
> -  [AC_CHECK_LIB(nl-3, nl_socket_alloc,
> +  AC_CHECK_LIB(nl, nl_socket_modify_cb,
>      [
>        USE_NL="LIBIPVS_USE_NL"
> -      CFLAGS="$CFLAGS $(pkg-config --libs --cflags libnl-3.0)"
> -      LIBS="$LIBS -lnl-3"
> -      AC_CHECK_LIB(nl-genl-3, genl_connect,
> -       [
> -         LIBS="$LIBS -lnl-3 -lnl-genl-3"
> -       ],
> -       [
> -         AC_MSG_ERROR([libnl-3 is installed but not libnl-gen-3. Please, install libnl-gen-3.])
> -       ])
> +      CFLAGS="$CFLAGS -DFALLBACK_LIBNL1"
> +      LIBS="$LIBS $(pkg-config --libs libnl-1)"
>      ],
> -    [
> +    [                                                                                           
>        USE_NL="LIBIPVS_DONTUSE_NL"
>        AC_MSG_WARN([keepalived will be built without libnl support.])
>      ])
> -  ])
> +])
>  
>  dnl ----[ Kernel version check ]----
>  CPPFLAGS="$CPPFLAGS -I$kernelinc"
> -- 
> 1.8.1.4
> 

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