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Previously, since we acquired the libcamera camera upon open(), it was
impossible to support multiple open, as any subsequent opens would
return error because the camera would already be acquired.
To fix this, we first initialize the camera in the first call to
V4L2CameraProxy::open(), just to heat up the stream format cache. We
then add ownership by a V4L2CameraFile of a V4L2Camera via the
V4L2CameraProxy. All vidioc ioctls prior to reqbufs > 0 (except for
s_fmt) are able to access the camera without ownership. A call to
reqbufs > 0 (and s_fmt) will take ownership, and the ownership will be
released at reqbufs = 0. While ownership is assigned, the eventfd that
should be signaled (and cleared) by V4L2Camera and V4L2CameraProxy is
set to the V4L2CameraFile that has ownership, and is cleared when the
ownership is released. In case close() is called without a
reqbufs = 0 first, the ownership is also released on close().
We also use the V4L2CameraFile to contain all the information specific
to an open instance of the file. This removes the need to keep track of
such information within V4L2CameraProxy via multiple maps from int fd to
info.
Since V4L2 does not expect reqbufs 0 to ever return error, make
V4L2CameraProxy::freeBuffers() return void.
Signed-off-by: Paul Elder <paul.elder@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
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Prepare for using the V4L2CameraFile as a container for file-specific
information in the V4L2 compatibility layer by making it a required
argument for all V4L2CameraProxy calls that are directed from
V4L2CompatManager, which are intercepted via LD_PRELOAD. Change
V4L2CameraFile accordingly.
Also change V4L2CompatManager accordingly. Instead of keeping a map of
file descriptors to V4L2CameraProxy instances, we keep a map of
V4L2CameraFile instances to V4L2CameraProxy instances. When the
proxy methods are called, feed the file as a parameter.
The dup function is also modified, in that it is removed from
V4L2CameraProxy, and is handled completely in V4L2CompatManager, as a
map from file descriptors to V4L2CameraFile instances.
Signed-off-by: Paul Elder <paul.elder@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
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Some applications (eg. Firefox, Google Chrome, Skype) use open64,
openat64, and mmap64 instead of their non-64 versions that we currently
intercept. Intercept these calls as well. _LARGEFILE64_SOURCE needs to
be set so that the 64-bit symbols are available and not synonymous to
the non-64-bit versions on 64-bit systems.
Also, since we set _FILE_OFFSET_BITS to 32 to force the various open and
mmap symbols that we export to not be the 64-bit versions, our dlsym to
get the original open and mmap calls will not automatically be converted
to their 64-bit versions. Since we intercept both 32-bit and 64-bit
versions of open and mmap, we should be using the 64-bit version to
service both. Fetch the 64-bit versions of openat and mmap directly.
musl defines the 64-bit symbols as macros that are equivalent to the
non-64-bit symbols, so we put compile guards that check if the 64-bit
symbols are defined.
Signed-off-by: Paul Elder <paul.elder@ideasonboard.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
Tested-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> # Compile with musl
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
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To support polling, we need to be able to signal when data is
available to be read (POLLIN), as well as events (POLLPRI). Add the
necessary calls to eventfd to allow signaling POLLIN. We signal POLLIN
by writing writing to the eventfd, and clear it by reading from the
eventfd, upon VIDIOC_DQBUF.
Note that eventfd does not support signaling POLLPRI, so we don't yet
support V4L2 events.
Signed-off-by: Paul Elder <paul.elder@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
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The V4L2 compatibility layer is licensed under the GPL. It is compiled
as a binary separate from libcamera.so, and is loaded into the address
space of processes through LD_PRELOAD to intercept calls to the C
library.
It is our understanding and intent that the GPL license doesn't
propagate to the binaries whose calls are intercepted, considering those
binaries are not derivative work of the V4L2 compatibility layer and are
not designed to be linked to the V4L2 compatibility layer. There is
however a possibly grey area if binaries are packaged with a shell
script wrapper that loads the V4L2 compatibility layer. This could lead
to license-related issues if such packaging is performed by Linux
distributions or system integrators.
To clarify the intent and lift the doubts, relicense the V4L2
compatibility layer under the LGPL. The V4L2 compatibility layer code
itself still benefits from the license protection, while its usage with
third-party binaries is clearly allowed as intended.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Jacopo Mondi <jacopo@jmondi.org>
Acked-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Acked-by: Paul Elder <paul.elder@ideasonboard.com>
Acked-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
Acked-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
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const reference
PixelFormat was previously an alias for unsigned int but is now a
class. Make all functions taking PixelFormat do so as a const reference.
Signed-off-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
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In the upcoming FrameBuffer API the memory mapping of buffers will be
left to the user of the FrameBuffer objects. Prepare the V4L2
compatibility layer to this upcoming change to ease conversion to the
new API.
Signed-off-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
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Calling vidioc_s_fmt() calls vidioc_try_fmt() duplicating prinouts.
Breakout try format procedure and call it from both functions.
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>
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To clarify code, adopt the following rules for format helpers:
- All variables representing V4L2 pixel formats shall use uint32_t
- All variables representing DRM pixel formats shall use PixelFormat
- Functions returning positive values only shall not have a signed
return type
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
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Add libcamera V4L2 compatibility layer.
This initial implementation supports the minimal set of V4L2 operations,
which allows getting, setting, and enumerating formats, and streaming
frames from a video device. Some data about the wrapped V4L2 video
device are hardcoded.
Add a build option named 'v4l2' and adjust the build system to
selectively compile the V4L2 compatibility layer.
For now we match the V4L2 device node to a libcamera camera based on a
devnum that a pipeline handler may optionally map to a libcamera
camera.
Signed-off-by: Paul Elder <paul.elder@ideasonboard.com>
Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
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