From 977cfbd526f2da1cfce5c5c2b187c83af3d3efdc Mon Sep 17 00:00:00 2001 From: Paul Elder Date: Thu, 2 May 2019 16:50:49 -0400 Subject: libcamera: device_enumerator: add DeviceEnumeratorSysfs class A udev-based device enumerator is not sufficient, since libudev is an optional dependency, or udev might fail. In these cases, we should fall back to using sysfs to enumerate devices. Add a DeviceEnumeratorSysfs class which is a specialization of DeviceEnumerator that uses sysfs to enumerate media devices on the system. Signed-off-by: Paul Elder Reviewed-by: Laurent Pinchart --- src/libcamera/device_enumerator.cpp | 6 +- src/libcamera/device_enumerator_sysfs.cpp | 105 ++++++++++++++++++++++++ src/libcamera/include/device_enumerator_sysfs.h | 28 +++++++ src/libcamera/meson.build | 2 + 4 files changed, 139 insertions(+), 2 deletions(-) create mode 100644 src/libcamera/device_enumerator_sysfs.cpp create mode 100644 src/libcamera/include/device_enumerator_sysfs.h (limited to 'src') diff --git a/src/libcamera/device_enumerator.cpp b/src/libcamera/device_enumerator.cpp index f6878b3d..259eec41 100644 --- a/src/libcamera/device_enumerator.cpp +++ b/src/libcamera/device_enumerator.cpp @@ -6,6 +6,7 @@ */ #include "device_enumerator.h" +#include "device_enumerator_sysfs.h" #include "device_enumerator_udev.h" #include @@ -153,8 +154,9 @@ std::unique_ptr DeviceEnumerator::create() * Either udev is not available or udev initialization failed. Fall back * on the sysfs enumerator. */ - - /** \todo Add a sysfs-based enumerator. */ + enumerator = utils::make_unique(); + if (!enumerator->init()) + return enumerator; return nullptr; } diff --git a/src/libcamera/device_enumerator_sysfs.cpp b/src/libcamera/device_enumerator_sysfs.cpp new file mode 100644 index 00000000..f3054d5e --- /dev/null +++ b/src/libcamera/device_enumerator_sysfs.cpp @@ -0,0 +1,105 @@ +/* SPDX-License-Identifier: LGPL-2.1-or-later */ +/* + * Copyright (C) 2019, Google Inc. + * + * device_enumerator_sysfs.cpp - sysfs-based device enumerator + */ + +#include "device_enumerator_sysfs.h" + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include "log.h" + +namespace libcamera { + +LOG_DECLARE_CATEGORY(DeviceEnumerator) + +int DeviceEnumeratorSysfs::init() +{ + return 0; +} + +int DeviceEnumeratorSysfs::enumerate() +{ + struct dirent *ent; + DIR *dir; + + static const char * const sysfs_dirs[] = { + "/sys/subsystem/media/devices", + "/sys/bus/media/devices", + "/sys/class/media/devices", + }; + + for (const char *dirname : sysfs_dirs) { + dir = opendir(dirname); + if (dir) + break; + } + + if (!dir) { + LOG(DeviceEnumerator, Error) + << "No valid sysfs media device directory"; + return -ENODEV; + } + + while ((ent = readdir(dir)) != nullptr) { + if (strncmp(ent->d_name, "media", 5)) + continue; + + char *end; + unsigned int idx = strtoul(ent->d_name + 5, &end, 10); + if (*end != '\0') + continue; + + std::string devnode = "/dev/media" + std::to_string(idx); + + /* Verify that the device node exists. */ + struct stat devstat; + if (stat(devnode.c_str(), &devstat) < 0) { + LOG(DeviceEnumerator, Warning) + << "Device node /dev/media" << idx + << " should exist but doesn't"; + continue; + } + + addDevice(devnode); + } + + closedir(dir); + + return 0; +} + +std::string DeviceEnumeratorSysfs::lookupDeviceNode(int major, int minor) +{ + std::string deviceNode; + std::string line; + std::ifstream ueventFile; + + ueventFile.open("/sys/dev/char/" + std::to_string(major) + ":" + + std::to_string(minor) + "/uevent"); + if (!ueventFile) + return std::string(); + + while (ueventFile >> line) { + if (line.find("DEVNAME=") == 0) { + deviceNode = "/dev/" + line.substr(strlen("DEVNAME=")); + break; + } + } + + ueventFile.close(); + + return deviceNode; +} + +} /* namespace libcamera */ diff --git a/src/libcamera/include/device_enumerator_sysfs.h b/src/libcamera/include/device_enumerator_sysfs.h new file mode 100644 index 00000000..8d3adc91 --- /dev/null +++ b/src/libcamera/include/device_enumerator_sysfs.h @@ -0,0 +1,28 @@ +/* SPDX-License-Identifier: LGPL-2.1-or-later */ +/* + * Copyright (C) 2019, Google Inc. + * + * device_enumerator_sysfs.h - sysfs-based device enumerator + */ +#ifndef __LIBCAMERA_DEVICE_ENUMERATOR_SYSFS_H__ +#define __LIBCAMERA_DEVICE_ENUMERATOR_SYSFS_H__ + +#include + +#include "device_enumerator.h" + +namespace libcamera { + +class DeviceEnumeratorSysfs final : public DeviceEnumerator +{ +public: + int init(); + int enumerate(); + +private: + std::string lookupDeviceNode(int major, int minor); +}; + +} /* namespace libcamera */ + +#endif /* __LIBCAMERA_DEVICE_ENUMERATOR_SYSFS_H__ */ diff --git a/src/libcamera/meson.build b/src/libcamera/meson.build index 2b678237..8796f49b 100644 --- a/src/libcamera/meson.build +++ b/src/libcamera/meson.build @@ -4,6 +4,7 @@ libcamera_sources = files([ 'camera_manager.cpp', 'camera_sensor.cpp', 'device_enumerator.cpp', + 'device_enumerator_sysfs.cpp', 'event_dispatcher.cpp', 'event_dispatcher_poll.cpp', 'event_notifier.cpp', @@ -26,6 +27,7 @@ libcamera_sources = files([ libcamera_headers = files([ 'include/camera_sensor.h', 'include/device_enumerator.h', + 'include/device_enumerator_sysfs.h', 'include/device_enumerator_udev.h', 'include/event_dispatcher_poll.h', 'include/formats.h', -- cgit v1.2.1