libv4l: intercept get capabilites and report read capability

From: Hans de Goede <j.w.r.degoede@hhs.nl>

libv4l: intercept get capabilites and report read capability

Signed-off-by: Hans de Goede <j.w.r.degoede@hhs.nl>

2 files changed, 16 insertions, 1 deletions

diff --git a/v4l2-apps/lib/libv4l/ChangeLog b/v4l2-apps/lib/libv4l/ChangeLog
index 3fec060c3..b54ab92f4 100644
--- a/v4l2-apps/lib/libv4l/ChangeLog
+++ b/v4l2-apps/lib/libv4l/ChangeLog
@@ -4,6 +4,7 @@ libv4l-0.3.8
 * add pkg-config (.pc) files for easier detection if libv4l is available
 * check capabilities for streaming, if the driver cannot do streaming don't
   insert ourselves between the application and the driver
+* intercept get capabilites and report read capability (which we always offer)
 
 
 libv4l-0.3.7
diff --git a/v4l2-apps/lib/libv4l/libv4l2/libv4l2.c b/v4l2-apps/lib/libv4l/libv4l2/libv4l2.c
index 95c581079..930ef5f1e 100644
--- a/v4l2-apps/lib/libv4l/libv4l2/libv4l2.c
+++ b/v4l2-apps/lib/libv4l/libv4l2/libv4l2.c
@@ -550,6 +550,9 @@ int v4l2_ioctl (int fd, unsigned long int request, ...)
 
   /* Is this a capture request and do we need to take the stream lock? */
   switch (request) {
+    case VIDIOC_QUERYCAP:
+      is_capture_request = 1;
+      break;
     case VIDIOC_ENUM_FMT:
       if (((struct v4l2_fmtdesc *)arg)->type == V4L2_BUF_TYPE_VIDEO_CAPTURE)
 	is_capture_request = 1;
@@ -605,6 +608,17 @@ int v4l2_ioctl (int fd, unsigned long int request, ...)
 
 
   switch (request) {
+    case VIDIOC_QUERYCAP:
+      {
+	struct v4l2_capability *cap = arg;
+
+	result = syscall(SYS_ioctl, devices[index].fd, VIDIOC_QUERYCAP, cap);
+	if (result == 0)
+	  /* We always support read() as we fake it using mmap mode */
+	  cap->capabilities |= V4L2_CAP_READWRITE;
+      }
+      break;
+
     case VIDIOC_ENUM_FMT:
       result = v4lconvert_enum_fmt(devices[index].convert, arg);
       break;
@@ -727,7 +741,7 @@ int v4l2_ioctl (int fd, unsigned long int request, ...)
 	result = syscall(SYS_ioctl, devices[index].fd, VIDIOC_REQBUFS, req);
 	if (result < 0)
 	  break;
-	result = 0; // some drivers return the number of buffers on success
+	result = 0; /* some drivers return the number of buffers on success */
 
 	/* If we got more frames then we can handle lie to the app */
 	if (req->count > V4L2_MAX_NO_FRAMES)