From 96ed45b9711e5c70afc4f91eab0ed657ccfb9695 Mon Sep 17 00:00:00 2001 From: Kieran Bingham Date: Tue, 1 Nov 2022 18:00:51 +0000 Subject: libcamera: v4l2_device: Workaround faulty control menus Some UVC cameras have been identified that can provide V4L2 menu controls without any menu items. This leads to a segfault where we try to construct a ControlInfo(Span<>,default) with an empty span. Convert the v4l2ControlInfo and v4l2MenuControlInfo helper functions to return std::optional to be able to account in the caller if the control is valid, and only add acceptable controls to the supported control list. Menu controls without a list of menu items are no longer added as a valid control and a warning is logged. This also fixes a potential crash that would have occured in the unlikely event that a ctrl.minimum was set to less than 0. Bug: https://bugs.libcamera.org/show_bug.cgi?id=167 Reported-by: Marian Buschsieweke Reviewed-by: Jacopo Mondi Reviewed-by: Laurent Pinchart Signed-off-by: Kieran Bingham --- include/libcamera/internal/v4l2_device.h | 4 ++-- src/libcamera/v4l2_device.cpp | 28 +++++++++++++++++++++++----- 2 files changed, 25 insertions(+), 7 deletions(-) diff --git a/include/libcamera/internal/v4l2_device.h b/include/libcamera/internal/v4l2_device.h index 75304be1..50d4adbc 100644 --- a/include/libcamera/internal/v4l2_device.h +++ b/include/libcamera/internal/v4l2_device.h @@ -70,8 +70,8 @@ protected: private: static ControlType v4l2CtrlType(uint32_t ctrlType); static std::unique_ptr v4l2ControlId(const v4l2_query_ext_ctrl &ctrl); - ControlInfo v4l2ControlInfo(const v4l2_query_ext_ctrl &ctrl); - ControlInfo v4l2MenuControlInfo(const v4l2_query_ext_ctrl &ctrl); + std::optional v4l2ControlInfo(const v4l2_query_ext_ctrl &ctrl); + std::optional v4l2MenuControlInfo(const v4l2_query_ext_ctrl &ctrl); void listControls(); void updateControls(ControlList *ctrls, diff --git a/src/libcamera/v4l2_device.cpp b/src/libcamera/v4l2_device.cpp index c17b323f..57a88d96 100644 --- a/src/libcamera/v4l2_device.cpp +++ b/src/libcamera/v4l2_device.cpp @@ -529,7 +529,7 @@ std::unique_ptr V4L2Device::v4l2ControlId(const v4l2_query_ext_ctrl & * \param[in] ctrl The v4l2_query_ext_ctrl that represents a V4L2 control * \return A ControlInfo that represents \a ctrl */ -ControlInfo V4L2Device::v4l2ControlInfo(const v4l2_query_ext_ctrl &ctrl) +std::optional V4L2Device::v4l2ControlInfo(const v4l2_query_ext_ctrl &ctrl) { switch (ctrl.type) { case V4L2_CTRL_TYPE_U8: @@ -566,14 +566,14 @@ ControlInfo V4L2Device::v4l2ControlInfo(const v4l2_query_ext_ctrl &ctrl) * * \return A ControlInfo that represents \a ctrl */ -ControlInfo V4L2Device::v4l2MenuControlInfo(const struct v4l2_query_ext_ctrl &ctrl) +std::optional V4L2Device::v4l2MenuControlInfo(const struct v4l2_query_ext_ctrl &ctrl) { std::vector indices; struct v4l2_querymenu menu = {}; menu.id = ctrl.id; if (ctrl.minimum < 0) - return ControlInfo(); + return std::nullopt; for (int32_t index = ctrl.minimum; index <= ctrl.maximum; ++index) { menu.index = index; @@ -583,6 +583,14 @@ ControlInfo V4L2Device::v4l2MenuControlInfo(const struct v4l2_query_ext_ctrl &ct indices.push_back(index); } + /* + * Some faulty UVC devices are known to return an empty menu control. + * Controls without a menu option can not be set, or read, so they are + * not exposed. + */ + if (indices.size() == 0) + return std::nullopt; + return ControlInfo(indices, ControlValue(static_cast(ctrl.default_value))); } @@ -631,7 +639,17 @@ void V4L2Device::listControls() controlIdMap_[ctrl.id] = controlIds_.back().get(); controlInfo_.emplace(ctrl.id, ctrl); - ctrls.emplace(controlIds_.back().get(), v4l2ControlInfo(ctrl)); + std::optional info = v4l2ControlInfo(ctrl); + + if (!info) { + LOG(V4L2, Error) + << "Control " << ctrl.name + << " cannot be registered"; + + continue; + } + + ctrls.emplace(controlIds_.back().get(), *info); } controls_ = ControlInfoMap(std::move(ctrls), controlIdMap_); @@ -670,7 +688,7 @@ void V4L2Device::updateControlInfo() continue; } - info = v4l2ControlInfo(ctrl); + info = *v4l2ControlInfo(ctrl); } } -- cgit v1.2.1