Add helper functions that allow for easy instantiation of media_device
object basing on whether the media device contains v4l2 subdev with
given file descriptor.
Signed-off-by: Jacek Anaszewski <j.anaszewski@xxxxxxxxxxx>
Acked-by: Kyungmin Park <kyungmin.park@xxxxxxxxxxx>
---
utils/media-ctl/libmediactl.c | 131 +++++++++++++++++++++++++++++++++++++++++-
utils/media-ctl/mediactl.h | 27 +++++++++
2 files changed, 156 insertions(+), 2 deletions(-)
diff --git a/utils/media-ctl/libmediactl.c b/utils/media-ctl/libmediactl.c
index 155b65f..d347a40 100644
--- a/utils/media-ctl/libmediactl.c
+++ b/utils/media-ctl/libmediactl.c
@@ -27,6 +27,7 @@
#include <sys/sysmacros.h>
#include <ctype.h>
+#include <dirent.h>
#include <errno.h>
#include <fcntl.h>
#include <stdbool.h>
@@ -440,8 +441,9 @@ static int media_get_devname_udev(struct udev *udev,
return -EINVAL;
devnum = makedev(entity->info.v4l.major, entity->info.v4l.minor);
- media_dbg(entity->media, "looking up device: %u:%u\n",
- major(devnum), minor(devnum));
+ if (entity->media)
+ media_dbg(entity->media, "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);
@@ -523,6 +525,7 @@ static int media_get_devname_sysfs(struct media_entity *entity)
return 0;
}
+
static int media_enum_entities(struct media_device *media)
{
struct media_entity *entity;
@@ -707,6 +710,92 @@ struct media_device *media_device_new(const char *devnode)
return media;
}
+struct media_device *media_device_new_by_subdev_fd(int fd, struct media_entity **fd_entity)
+{
+ char video_devname[32], device_dir_path[256], media_dev_path[256], media_major_minor[10];
+ struct media_device *media = NULL;
+ struct dirent *entry;
+ struct media_entity tmp_entity;
+ DIR *device_dir;
+ struct udev *udev;
+ char *p;
+ int ret, i;
+
+ if (fd_entity == NULL)
+ return NULL;
+
+ ret = media_get_devname_by_fd(fd, video_devname);
+ if (ret < 0)
+ return NULL;
+
+ p = strrchr(video_devname, '/');
+ if (p == NULL)
+ return NULL;
+
+ ret = media_udev_open(&udev);
+ if (ret < 0)
+ return NULL;
+
+ sprintf(device_dir_path, "/sys/class/video4linux/%s/device/", p + 1);
+
+ device_dir = opendir(device_dir_path);
+ if (device_dir == NULL)
+ return NULL;
+
+ while ((entry = readdir(device_dir))) {
+ if (strncmp(entry->d_name, "media", 4))
+ continue;
+
+ sprintf(media_dev_path, "%s%s/dev", device_dir_path, entry->d_name);
+
+ fd = open(media_dev_path, O_RDONLY);
+ if (fd < 0)
+ continue;
+
+ ret = read(fd, media_major_minor, sizeof(media_major_minor));
+ if (ret < 0)
+ continue;
+
+ sscanf(media_major_minor, "%d:%d", &tmp_entity.info.dev.major, &tmp_entity.info.dev.minor);
+
+ /* Try to get the device name via udev */
+ if (media_get_devname_udev(udev, &tmp_entity)) {
+ /* Fall back to get the device name via sysfs */
+ if (media_get_devname_sysfs(&tmp_entity))
+ continue;
+ }
+
+ media = media_device_new(tmp_entity.devname);
+ if (media == NULL)
+ continue;
+
+ ret = media_device_enumerate(media);
+ if (ret < 0) {
+ media_dbg(media, "Failed to enumerate %s (%d)\n",
+ tmp_entity.devname, ret);
+ media_device_unref(media);
+ media = NULL;
+ continue;
+ }
+
+ /* Get the entity associated with given fd */
+ for (i = 0; i < media->entities_count; i++) {
+ struct media_entity *entity = &media->entities[i];
+
+ if (!strcmp(entity->devname, video_devname)) {
+ *fd_entity = &media->entities[i];
+ break;
+ }
+ }
+
+ break;
+ }
+
+ media_udev_close(udev);
+
+ return media;
+}
+
struct media_device *media_device_new_emulated(struct media_device_info *info)
{
struct media_device *media;
@@ -748,6 +837,44 @@ void media_device_unref(struct media_device *media)
free(media);
}
+int media_get_devname_by_fd(int fd, char *node_name)
+{
+ struct udev *udev;
+ struct media_entity tmp_entity;
+ struct stat stat;
+ int ret, ret_udev;
+
+ if (node_name == NULL)
+ return -EINVAL;
+
+ ret = fstat(fd, &stat);
+ if (ret < 0)
+ return -errno;
+
+ tmp_entity.info.v4l.major = MAJOR(stat.st_rdev);
+ tmp_entity.info.v4l.minor = MINOR(stat.st_rdev);
+
+ ret_udev = media_udev_open(&udev);
+ if (ret_udev < 0)
+ printf("Can't get udev context\n");
+
+ /* Try to get the device name via udev */
+ ret = media_get_devname_udev(udev, &tmp_entity);
+ if (!ret)
+ goto out;
+
+ ret = media_get_devname_sysfs(&tmp_entity);
+ if (ret < 0)
+ goto err_get_devname;
+
+out:
+ strncpy(node_name, tmp_entity.devname, sizeof(tmp_entity.devname));
+err_get_devname:
+ if (!ret_udev)
+ media_udev_close(udev);
+ return ret;
+}
+
int media_device_add_entity(struct media_device *media,
const struct media_entity_desc *desc,
const char *devnode)
diff --git a/utils/media-ctl/mediactl.h b/utils/media-ctl/mediactl.h
index b1f33cd..580a25a 100644
--- a/utils/media-ctl/mediactl.h
+++ b/utils/media-ctl/mediactl.h
@@ -76,6 +76,21 @@ struct media_device *media_device_new(const char *devnode);
struct media_device *media_device_new_emulated(struct media_device_info *info);
/**
+ * @brief Create a new media device contatning entity associated with v4l2 subdev fd.
+ * @param fd - file descriptor of a v4l2 subdev.
+ * @param fd_entity - media entity associated with the v4l2 subdev.
+ *
+ * Create a representation of the media device referenced by the v4l2-subdev.
+ * The media device instance is initialized with enumerated entities and links.
+ *
+ * Media devices are reference-counted, see media_device_ref() and
+ * media_device_unref() for more information.
+ *
+ * @return A pointer to the new media device or NULL if error occurred.
+ */
+struct media_device *media_device_new_by_subdev_fd(int fd, struct media_entity **fd_entity);
+
+/**
* @brief Take a reference to the device.
* @param media - device instance.
*
@@ -231,6 +246,18 @@ const struct media_link *media_entity_get_link(struct media_entity *entity,
const char *media_entity_get_devname(struct media_entity *entity);
/**
+ * @brief Get the device node name by its file descriptor
+ * @param fd - file descriptor of a device.
+ * @param node_name - output device node name string.
+ *
+ * This function returns the full path and name to the device node corresponding
+ * to the given file descriptor.
+ *
+ * @return 0 on success, or a negative error code on failure.
+ */
+int media_get_devname_by_fd(int fd, char *node_name);
+
+/**
* @brief Get the type of an entity.
* @param entity - the entity.
*
--
1.9.1
--
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