Re: [media-ctl][PATCHv2 3/4] libmediactl: use udev conditionally to get a devname

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 configure.in    |   22 ++++++++++++++++++++++
 src/Makefile.am |    2 ++
 src/media.c     |   50 ++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 74 insertions(+), 0 deletions(-)

diff --git a/configure.in b/configure.in
index fd4c70c..45e0663 100644
--- a/configure.in
+++ b/configure.in

@@ -13,6 +13,28 @@ AC_PROG_LIBTOOL

 # Checks for libraries.

+AC_ARG_WITH([libudev],
+    AS_HELP_STRING([--without-libudev],
+        [Ignore presence of libudev and disable it]))
+
+AS_IF([test "x$with_libudev" != "xno"],
+    [PKG_CHECK_MODULES(libudev, libudev, have_libudev=yes,

have_libudev=no)], +    [have_libudev=no])
+
+AS_IF([test "x$have_libudev" = "xyes"],
+    [
+        AC_DEFINE([HAVE_LIBUDEV], [], [Use libudev])
+        LIBUDEV_CFLAGS="$lbudev_CFLAGS"
+        LIBUDEV_LIBS="$libudev_LIBS"
+        AC_SUBST(LIBUDEV_CFLAGS)
+        AC_SUBST(LIBUDEV_LIBS)
+    ],
+    [AS_IF([test "x$with_libudev" = "xyes"],
+        [AC_MSG_ERROR([libudev requested but not found])
+    ])
+])
+
+
 # Kernel headers path.
 AC_ARG_WITH(kernel-headers,
     [AC_HELP_STRING([--with-kernel-headers=DIR],

diff --git a/src/Makefile.am b/src/Makefile.am
index 267ea83..52628d2 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am

@@ -5,6 +5,8 @@ mediactl_includedir=$(includedir)/mediactl
 mediactl_include_HEADERS = media.h subdev.h

 bin_PROGRAMS = media-ctl
+media_ctl_CFLAGS = $(LIBUDEV_CFLAGS)
+media_ctl_LDFLAGS = $(LIBUDEV_LIBS)
 media_ctl_SOURCES = main.c options.c options.h tools.h
 media_ctl_LDADD = libmediactl.la libv4l2subdev.la

diff --git a/src/media.c b/src/media.c
index fc05a86..e159526 100644
--- a/src/media.c
+++ b/src/media.c

@@ -17,6 +17,8 @@
  * with this program; if not, write to the Free Software Foundation, Inc.,
  */

+#include "config.h"
+
 #include <sys/ioctl.h>
 #include <sys/stat.h>
 #include <sys/types.h>

@@ -31,6 +33,10 @@
 #include <linux/videodev2.h>
 #include <linux/media.h>

+#ifdef HAVE_LIBUDEV
+#include <libudev.h>
+#endif	/* HAVE_LIBUDEV */
+
 #include "media.h"
 #include "tools.h"

@@ -245,6 +251,37 @@ static int media_enum_links(struct media_device

*media) return ret;
 }

+#ifdef HAVE_LIBUDEV
+
+static struct udev *udev;

+
+static int media_get_devname(struct media_entity *entity)
+{
+	dev_t devnum;
+	struct udev_device *device;
+	const char *p;
+	int ret = -ENODEV;
+
+	if (media_entity_type(entity) != MEDIA_ENT_T_DEVNODE &&
+	    media_entity_type(entity) != MEDIA_ENT_T_V4L2_SUBDEV)
+		return 0;
+
+	devnum = makedev(entity->info.v4l.major, entity->info.v4l.minor);
+	printf("looking up device: %u:%u\n", major(devnum), minor(devnum));
+	device = udev_device_new_from_devnum(udev, 'c', devnum);
+	if (device) {
+		p = udev_device_get_devnode(device);
+		if (p)
+			snprintf(entity->devname, sizeof(entity->devname), "%s", p);
+		ret = 0;
+	}
+
+	udev_device_unref(device);
+	return ret;
+}
+
+#else	/* HAVE_LIBUDEV */
+
 static int media_get_devname(struct media_entity *entity)
 {
 	struct stat devstat;

@@ -284,6 +321,7 @@ static int media_get_devname(struct media_entity

*entity)

 	return 0;
 }
+#endif	/* HAVE_LIBUDEV */

 static int media_enum_entities(struct media_device *media)
 {

@@ -292,6 +330,14 @@ static int media_enum_entities(struct media_device

*media) __u32 id;
 	int ret = 0;

+#ifdef HAVE_LIBUDEV
+	udev = udev_new();
+	if (udev == NULL) {
+		printf("unable to allocate memory for context\n");
+		return -ENOMEM;
+	}
+#endif	/* HAVE_LIBUDEV */
+

 	for (id = 0; ; id = entity->info.id) {
 		size = (media->entities_count + 1) * sizeof(*media->entities);
 		media->entities = realloc(media->entities, size);

@@ -327,6 +373,10 @@ static int media_enum_entities(struct media_device

*media) media_get_devname(entity);
 	}

+#ifdef HAVE_LIBUDEV
+	udev_unref(udev);
+	udev = NULL;
+#endif
 	return ret;
 }