From 305ae25455b1f19ad2eda92523bd553fd8bc72fd Mon Sep 17 00:00:00 2001
From: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Date: Sun, 20 Aug 2017 23:58:44 +0200
Subject: [PATCH] configure.ac: drop --disable-libv4l, disable plugin support
 instead

In commit 2e604dfbcd09b93f0808cedb2a0b324c5569a599 ("configure.ac: add
--disable-libv4l option"), an option --disable-libv4l was added. As
part of this, libv4l is no longer built at all in static linking
configurations, just because libv4l uses dlopen() for plugin support.

However, plugin support is only a side feature of libv4l, and one may
need to use libv4l in static configurations, just without plugin
support.

Therefore, this commit:

 - Essentially reverts 2e604dfbcd09b93f0808cedb2a0b324c5569a599, so
   that libv4l can be built in static linking configurations again.

 - Adjusts the compilation of libv4l2 so that the plugin support is
   not compiled in when dlopen() in static linking configuration
   (dlopen is not available).

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Submitted-upstream: https://www.mail-archive.com/linux-media@vger.kernel.org/msg117449.html
---
 Makefile.am                       | 11 ++---------
 configure.ac                      | 15 +++------------
 lib/libv4l2/Makefile.am           |  6 +++++-
 lib/libv4l2/libv4l2-priv.h        | 14 ++++++++++++++
 utils/Makefile.am                 |  6 +-----
 utils/v4l2-compliance/Makefile.am |  4 ----
 utils/v4l2-ctl/Makefile.am        |  4 ----
 7 files changed, 25 insertions(+), 35 deletions(-)

diff --git a/Makefile.am b/Makefile.am
index 07c3ef8..e603472 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -1,17 +1,10 @@
 AUTOMAKE_OPTIONS = foreign
 ACLOCAL_AMFLAGS = -I m4
 
-SUBDIRS = v4l-utils-po libdvbv5-po
-
-if WITH_LIBV4L
-SUBDIRS += lib
-endif
+SUBDIRS = v4l-utils-po libdvbv5-po lib
 
 if WITH_V4LUTILS
-SUBDIRS += utils
-if WITH_LIBV4L
-SUBDIRS += contrib
-endif
+SUBDIRS += utils contrib
 endif
 
 EXTRA_DIST = android-config.h bootstrap.sh doxygen_libdvbv5.cfg include COPYING.libv4l \
diff --git a/configure.ac b/configure.ac
index 58fb688..2ecb4a1 100644
--- a/configure.ac
+++ b/configure.ac
@@ -374,14 +374,6 @@ AC_ARG_ENABLE(libdvbv5,
    esac]
 )
 
-AC_ARG_ENABLE(libv4l,
-  AS_HELP_STRING([--disable-libv4l], [disable libv4l compilation]),
-  [case "${enableval}" in
-     yes | no ) ;;
-     *) AC_MSG_ERROR(bad value ${enableval} for --disable-libv4l) ;;
-   esac]
-)
-
 AC_ARG_ENABLE(dyn-libv4l,
   AS_HELP_STRING([--disable-dyn-libv4l], [disable dynamic libv4l support]),
   [case "${enableval}" in
@@ -439,7 +431,6 @@ AM_CONDITIONAL([WITH_LIBDVBV5],     [test x$enable_libdvbv5  != xno -a x$have_li
 AM_CONDITIONAL([WITH_DVBV5_REMOTE], [test x$enable_libdvbv5  != xno -a x$have_libudev = xyes -a x$have_pthread = xyes])
 
 AM_CONDITIONAL([WITH_DYN_LIBV4L],   [test x$enable_dyn_libv4l != xno])
-AM_CONDITIONAL([WITH_LIBV4L],       [test x$enable_libv4l    != xno -a x$enable_shared != xno])
 AM_CONDITIONAL([WITH_V4LUTILS],	    [test x$enable_v4l_utils != xno -a x$linux_os = xyes])
 AM_CONDITIONAL([WITH_QV4L2],	    [test x${qt_pkgconfig} = xtrue -a x$enable_qv4l2 != xno])
 AM_CONDITIONAL([WITH_V4L_PLUGINS],  [test x$enable_dyn_libv4l != xno -a x$enable_shared != xno])
@@ -467,11 +458,12 @@ AM_COND_IF([WITH_LIBDVBV5], [USE_LIBDVBV5="yes"], [USE_LIBDVBV5="no"])
 AM_COND_IF([WITH_DVBV5_REMOTE], [USE_DVBV5_REMOTE="yes"
 				 AC_DEFINE([HAVE_DVBV5_REMOTE], [1], [Usage of DVBv5 remote enabled])],
 			        [USE_DVBV5_REMOTE="no"])
-AM_COND_IF([WITH_LIBV4L], [USE_LIBV4L="yes"], [USE_LIBV4L="no"])
 AM_COND_IF([WITH_DYN_LIBV4L], [USE_DYN_LIBV4L="yes"], [USE_DYN_LIBV4L="no"])
 AM_COND_IF([WITH_V4LUTILS], [USE_V4LUTILS="yes"], [USE_V4LUTILS="no"])
 AM_COND_IF([WITH_QV4L2], [USE_QV4L2="yes"], [USE_QV4L2="no"])
-AM_COND_IF([WITH_V4L_PLUGINS], [USE_V4L_PLUGINS="yes"], [USE_V4L_PLUGINS="no"])
+AM_COND_IF([WITH_V4L_PLUGINS], [USE_V4L_PLUGINS="yes"
+				AC_DEFINE([HAVE_V4L_PLUGINS], [1], [V4L plugin support enabled])],
+				[USE_V4L_PLUGINS="no"])
 AM_COND_IF([WITH_V4L_WRAPPERS], [USE_V4L_WRAPPERS="yes"], [USE_V4L_WRAPPERS="no"])
 AM_COND_IF([WITH_GCONV], [USE_GCONV="yes"], [USE_GCONV="no"])
 AM_COND_IF([WITH_V4L2_CTL_LIBV4L], [USE_V4L2_CTL_LIBV4L="yes"], [USE_V4L2_CTL_LIBV4L="no"])
@@ -503,7 +495,6 @@ compile time options summary
 
     gconv                      : $USE_GCONV
 
-    libv4l                     : $USE_LIBV4L
     dynamic libv4l             : $USE_DYN_LIBV4L
     v4l_plugins                : $USE_V4L_PLUGINS
     v4l_wrappers               : $USE_V4L_WRAPPERS
diff --git a/lib/libv4l2/Makefile.am b/lib/libv4l2/Makefile.am
index 811c45c..3a1bb90 100644
--- a/lib/libv4l2/Makefile.am
+++ b/lib/libv4l2/Makefile.am
@@ -15,7 +15,11 @@ else
 noinst_LTLIBRARIES = libv4l2.la
 endif
 
-libv4l2_la_SOURCES = libv4l2.c v4l2-plugin.c log.c libv4l2-priv.h
+libv4l2_la_SOURCES = libv4l2.c log.c libv4l2-priv.h
+if WITH_V4L_PLUGINS
+libv4l2_la_SOURCES += v4l2-plugin.c
+endif
+
 libv4l2_la_CPPFLAGS = $(CFLAG_VISIBILITY) $(ENFORCE_LIBV4L_STATIC)
 libv4l2_la_LDFLAGS = $(LIBV4L2_VERSION) -lpthread $(DLOPEN_LIBS) $(ENFORCE_LIBV4L_STATIC)
 libv4l2_la_LIBADD = ../libv4lconvert/libv4lconvert.la
diff --git a/lib/libv4l2/libv4l2-priv.h b/lib/libv4l2/libv4l2-priv.h
index 343db5e..1924c91 100644
--- a/lib/libv4l2/libv4l2-priv.h
+++ b/lib/libv4l2/libv4l2-priv.h
@@ -107,10 +107,24 @@ struct v4l2_dev_info {
 };
 
 /* From v4l2-plugin.c */
+#if defined(HAVE_V4L_PLUGINS)
 void v4l2_plugin_init(int fd, void **plugin_lib_ret, void **plugin_priv_ret,
 		      const struct libv4l_dev_ops **dev_ops_ret);
 void v4l2_plugin_cleanup(void *plugin_lib, void *plugin_priv,
 			 const struct libv4l_dev_ops *dev_ops);
+#else
+static inline void v4l2_plugin_init(int fd, void **plugin_lib_ret, void **plugin_priv_ret,
+				    const struct libv4l_dev_ops **dev_ops_ret)
+{
+	*dev_ops_ret = v4lconvert_get_default_dev_ops();
+	*plugin_lib_ret = NULL;
+	*plugin_priv_ret = NULL;
+}
+static inline void v4l2_plugin_cleanup(void *plugin_lib, void *plugin_priv,
+				       const struct libv4l_dev_ops *dev_ops)
+{
+}
+#endif /* WITH_V4L_PLUGINS */
 
 /* From log.c */
 extern const char *v4l2_ioctls[];
diff --git a/utils/Makefile.am b/utils/Makefile.am
index ce710c2..d7708cc 100644
--- a/utils/Makefile.am
+++ b/utils/Makefile.am
@@ -13,12 +13,8 @@ SUBDIRS = \
 	v4l2-sysfs-path \
 	cec-ctl \
 	cec-compliance \
-	cec-follower
-
-if WITH_LIBV4L
-SUBDIRS += \
+	cec-follower \
 	rds-ctl
-endif
 
 if WITH_LIBDVBV5
 SUBDIRS += \
diff --git a/utils/v4l2-compliance/Makefile.am b/utils/v4l2-compliance/Makefile.am
index 0240a50..c2b5919 100644
--- a/utils/v4l2-compliance/Makefile.am
+++ b/utils/v4l2-compliance/Makefile.am
@@ -7,16 +7,12 @@ v4l2_compliance_SOURCES = v4l2-compliance.cpp v4l2-test-debug.cpp v4l2-test-inpu
 	v4l2-test-codecs.cpp v4l2-test-colors.cpp v4l2-compliance.h
 v4l2_compliance_CPPFLAGS = -I../common
 
-if WITH_LIBV4L
 if WITH_V4L2_COMPLIANCE_LIBV4L
 v4l2_compliance_LDADD = ../../lib/libv4l2/libv4l2.la ../../lib/libv4lconvert/libv4lconvert.la -lrt -lpthread
 else
 v4l2_compliance_LDADD = -lrt -lpthread
 DEFS += -DNO_LIBV4L2
 endif
-else
-DEFS += -DNO_LIBV4L2
-endif
 
 EXTRA_DIST = Android.mk fixme.txt v4l2-compliance.1
 
diff --git a/utils/v4l2-ctl/Makefile.am b/utils/v4l2-ctl/Makefile.am
index 4475aed..955647d 100644
--- a/utils/v4l2-ctl/Makefile.am
+++ b/utils/v4l2-ctl/Makefile.am
@@ -9,14 +9,10 @@ v4l2_ctl_SOURCES = v4l2-ctl.cpp v4l2-ctl.h v4l2-ctl-common.cpp v4l2-ctl-tuner.cp
 	v4l2-tpg-colors.c v4l2-tpg-core.c v4l-stream.c
 v4l2_ctl_CPPFLAGS = -I../common
 
-if WITH_LIBV4L
 if WITH_V4L2_CTL_LIBV4L
 v4l2_ctl_LDADD = ../../lib/libv4l2/libv4l2.la ../../lib/libv4lconvert/libv4lconvert.la -lrt -lpthread
 else
 DEFS += -DNO_LIBV4L2
 endif
-else
-DEFS += -DNO_LIBV4L2
-endif
 
 EXTRA_DIST = Android.mk v4l2-ctl.1
-- 
2.9.4