/* SPDX-License-Identifier: LGPL-2.1-or-later */ /* * Copyright (C) 2020, Collabora Ltd. * Author: Nicolas Dufresne * * gstlibcameraprovider.c - GStreamer Device Provider */ #include "gstlibcameraprovider.h" #include #include #include "gstlibcamerasrc.h" #include "gstlibcamera-utils.h" using namespace libcamera; GST_DEBUG_CATEGORY_STATIC(provider_debug); #define GST_CAT_DEFAULT provider_debug /** * \struct _GstLibcameraDevice * \brief libcamera GstDevice implementation * * This object is used by GstLibcameraProvider to abstract a libcamera * device. It also provides helpers to create and configure the * libcamerasrc GstElement to be used with this device. The implementation is * private to the plugin. */ enum { PROP_DEVICE_NAME = 1, }; #define GST_TYPE_LIBCAMERA_DEVICE gst_libcamera_device_get_type() G_DECLARE_FINAL_TYPE(GstLibcameraDevice, gst_libcamera_device, GST_LIBCAMERA, DEVICE, GstDevice) struct _GstLibcameraDevice { GstDevice parent; gchar *name; }; G_DEFINE_TYPE(GstLibcameraDevice, gst_libcamera_device, GST_TYPE_DEVICE) static GstElement * gst_libcamera_device_create_element(GstDevice *device, const gchar *name) { GstElement *source = gst_element_factory_make("libcamerasrc", name); /* * Provider and source lives in the same plugin, so making the source * should never fail. */ g_assert(source); g_object_set(source, "camera-name", GST_LIBCAMERA_DEVICE(device)->name, nullptr); return source; } static gboolean gst_libcamera_device_reconfigure_element(GstDevice *device, GstElement *element) { if (!GST_LIBCAMERA_IS_SRC(element)) return FALSE; g_object_set(element, "camera-name", GST_LIBCAMERA_DEVICE(device)->name, nullptr); return TRUE; } static void gst_libcamera_device_set_property(GObject *object, guint prop_id, const GValue *value, GParamSpec *pspec) { GstLibcameraDevice *device = GST_LIBCAMERA_DEVICE(object); switch (prop_id) { case PROP_DEVICE_NAME: device->name = g_value_dup_string(value); break; default: G_OBJECT_WARN_INVALID_PROPERTY_ID(object, prop_id, pspec); break; } } static void gst_libcamera_device_init([[maybe_unused]] GstLibcameraDevice *self) { } static void gst_libcamera_device_finalize(GObject *object) { GstLibcameraDevice *self = GST_LIBCAMERA_DEVICE(object); gpointer klass = gst_libcamera_device_parent_class; g_free(self->name); G_OBJECT_CLASS(klass)->finalize(object); } static void gst_libcamera_device_class_init(GstLibcameraDeviceClass *klass) { GstDeviceClass *device_class = GST_DEVICE_CLASS(klass); GObjectClass *object_class = G_OBJECT_CLASS(klass); device_class->create_element = gst_libcamera_device_create_element; device_class->reconfigure_element = gst_libcamera_device_reconfigure_element; object_class->set_property = gst_libcamera_device_set_property; object_class->finalize = gst_libcamera_device_finalize; GParamSpec *pspec = g_param_spec_string("name", "Name", "The name of the camera device", "", (GParamFlags)(G_PARAM_STATIC_STRINGS | G_PARAM_WRITABLE | G_PARAM_CONSTRUCT_ONLY)); g_object_class_install_property(object_class, PROP_DEVICE_NAME, pspec); } static GstDevice * gst_libcamera_device_new(const std::shared_ptr &camera) { g_autoptr(GstCaps) caps = gst_caps_new_empty(); const gchar *name = camera->id().c_str(); StreamRoles roles; roles.push_back(StreamRole::VideoRecording); std::unique_ptr config = camera->generateConfiguration(roles); for (const StreamConfiguration &stream_cfg : *config) { GstCaps *sub_caps = gst_libcamera_stream_formats_to_caps(stream_cfg.formats()); if (sub_caps) gst_caps_append(caps, sub_caps); } return GST_DEVICE(g_object_new(GST_TYPE_LIBCAMERA_DEVICE, /* \todo Use a unique identifier instead of camera name. */ "name", name, "display-name", name, "caps", caps, "device-class", "Source/Video", nullptr)); } /** * \struct _GstLibcameraProvider * \brief libcamera GstDeviceProvider implementation * * This GstFeature is used by GstDeviceMonitor to probe the available * libcamera devices. The implementation is private to the plugin. */ struct _GstLibcameraProvider { GstDeviceProvider parent; CameraManager *cm; }; G_DEFINE_TYPE_WITH_CODE(GstLibcameraProvider, gst_libcamera_provider, GST_TYPE_DEVICE_PROVIDER, GST_DEBUG_CATEGORY_INIT(provider_debug, "libcamera-provider", 0, "libcamera Device Provider")) static GList * gst_libcamera_provider_probe(GstDeviceProvider *provider) { GstLibcameraProvider *self = GST_LIBCAMERA_PROVIDER(provider); CameraManager *cm = self->cm; GList *devices = nullptr; gint ret; GST_INFO_OBJECT(self, "Probing cameras using libcamera"); /* \todo Move the CameraMananger start()/stop() calls into * GstDeviceProvider start()/stop() virtual function when CameraMananger * gains monitoring support. Meanwhile we need to cycle start()/stop() * to ensure every probe() calls return the latest list. */ ret = cm->start(); if (ret) { GST_ERROR_OBJECT(self, "Failed to retrieve device list: %s", g_strerror(-ret)); return nullptr; } for (const std::shared_ptr &camera : cm->cameras()) { GST_INFO_OBJECT(self, "Found camera '%s'", camera->id().c_str()); devices = g_list_append(devices, g_object_ref_sink(gst_libcamera_device_new(camera))); } cm->stop(); return devices; } static void gst_libcamera_provider_init(GstLibcameraProvider *self) { GstDeviceProvider *provider = GST_DEVICE_PROVIDER(self); self->cm = new CameraManager(); /* Avoid devices being duplicated. */ gst_device_provider_hide_provider(provider, "v4l2deviceprovider"); } static void gst_libcamera_provider_finalize(GObject *object) { GstLibcameraProvider *self = GST_LIBCAMERA_PROVIDER(object); gpointer klass = gst_libcamera_provider_parent_class; delete self->cm; return G_OBJECT_CLASS(klass)->finalize(object); } static void gst_libcamera_provider_class_init(GstLibcameraProviderClass *klass) { GstDeviceProviderClass *provider_class = GST_DEVICE_PROVIDER_CLASS(klass); GObjectClass *object_class = G_OBJECT_CLASS(klass); provider_class->probe = gst_libcamera_provider_probe; object_class->finalize = gst_libcamera_provider_finalize; gst_device_provider_class_set_metadata(provider_class, "libcamera Device Provider", "Source/Video", "List camera device using libcamera", "Nicolas Dufresne "); } 7'>117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375

/* SPDX-License-Identifier: LGPL-2.1-or-later */
/*
 * Copyright (C) 2019, Google Inc.
 *
 * Process object
 */

#include "libcamera/internal/process.h"

#include <algorithm>
#include <dirent.h>
#include <fcntl.h>
#include <list>
#include <signal.h>
#include <string.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
#include <vector>

#include <libcamera/base/event_notifier.h>
#include <libcamera/base/log.h>
#include <libcamera/base/utils.h>

/**
 * \file process.h
 * \brief Process object
 */

namespace libcamera {

LOG_DEFINE_CATEGORY(Process)

/**
 * \class ProcessManager
 * \brief Manager of processes
 *
 * The ProcessManager singleton keeps track of all created Process instances,
 * and manages the signal handling involved in terminating processes.
 */

namespace {

void sigact(int signal, siginfo_t *info, void *ucontext)
{
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wunused-result"
	/*
	 * We're in a signal handler so we can't log any message, and we need
	 * to continue anyway.
	 */
	char data = 0;
	write(ProcessManager::instance()->writePipe(), &data, sizeof(data));
#pragma GCC diagnostic pop

	const struct sigaction &oldsa = ProcessManager::instance()->oldsa();
	if (oldsa.sa_flags & SA_SIGINFO) {
		oldsa.sa_sigaction(signal, info, ucontext);
	} else {
		if (oldsa.sa_handler != SIG_IGN && oldsa.sa_handler != SIG_DFL)
			oldsa.sa_handler(signal);
	}
}

} /* namespace */

void ProcessManager::sighandler()
{
	char data;
	ssize_t ret = read(pipe_[0].get(), &data, sizeof(data));
	if (ret < 0) {
		LOG(Process, Error)
			<< "Failed to read byte from signal handler pipe";
		return;
	}

	for (auto it = processes_.begin(); it != processes_.end(); ) {
		Process *process = *it;

		int wstatus;
		pid_t pid = waitpid(process->pid_, &wstatus, WNOHANG);
		if (process->pid_ != pid) {
			++it;
			continue;
		}

		it = processes_.erase(it);
		process->died(wstatus);
	}
}

/**
 * \brief Register process with process manager
 * \param[in] proc Process to register
 *
 * This function registers the \a proc with the process manager. It
 * shall be called by the parent process after successfully forking, in
 * order to let the parent signal process termination.
 */
void ProcessManager::registerProcess(Process *proc)
{
	processes_.push_back(proc);
}

ProcessManager *ProcessManager::self_ = nullptr;

/**
 * \brief Construct a ProcessManager instance
 *
 * The ProcessManager class is meant to only be instantiated once, by the
 * CameraManager.
 */
ProcessManager::ProcessManager()
{
	if (self_)
		LOG(Process, Fatal)
			<< "Multiple ProcessManager objects are not allowed";

	sigaction(SIGCHLD, NULL, &oldsa_);

	struct sigaction sa;
	memset(&sa, 0, sizeof(sa));
	sa.sa_sigaction = &sigact;
	memcpy(&sa.sa_mask, &oldsa_.sa_mask, sizeof(sa.sa_mask));
	sigaddset(&sa.sa_mask, SIGCHLD);
	sa.sa_flags = oldsa_.sa_flags | SA_SIGINFO;

	sigaction(SIGCHLD, &sa, NULL);

	int pipe[2];
	if (pipe2(pipe, O_CLOEXEC | O_DIRECT | O_NONBLOCK))
		LOG(Process, Fatal)
			<< "Failed to initialize pipe for signal handling";

	pipe_[0] = UniqueFD(pipe[0]);
	pipe_[1] = UniqueFD(pipe[1]);

	sigEvent_ = new EventNotifier(pipe_[0].get(), EventNotifier::Read);
	sigEvent_->activated.connect(this, &ProcessManager::sighandler);

	self_ = this;
}

ProcessManager::~ProcessManager()
{
	sigaction(SIGCHLD, &oldsa_, NULL);

	delete sigEvent_;

	self_ = nullptr;
}

/**
 * \brief Retrieve the Process manager instance
 *
 * The ProcessManager is constructed by the CameraManager. This function shall
 * be used to retrieve the single instance of the manager.
 *
 * \return The Process manager instance
 */
ProcessManager *ProcessManager::instance()
{
	return self_;
}

/**
 * \brief Retrieve the Process manager's write pipe
 *
 * This function is meant only to be used by the static signal handler.
 *
 * \return Pipe for writing
 */
int ProcessManager::writePipe() const
{
	return pipe_[1].get();
}

/**
 * \brief Retrive the old signal action data
 *
 * This function is meant only to be used by the static signal handler.
 *
 * \return The old signal action data
 */
const struct sigaction &ProcessManager::oldsa() const
{
	return oldsa_;
}

/**
 * \class Process
 * \brief Process object
 *
 * The Process class models a process, and simplifies spawning new processes
 * and monitoring the exiting of a process.
 */

/**
 * \enum Process::ExitStatus
 * \brief Exit status of process
 * \var Process::NotExited
 * The process hasn't exited yet
 * \var Process::NormalExit
 * The process exited normally, either via exit() or returning from main
 * \var Process::SignalExit
 * The process was terminated by a signal (this includes crashing)
 */

Process::Process()
	: pid_(-1), running_(false), exitStatus_(NotExited), exitCode_(0)
{
}

Process::~Process()
{
	kill();
	/* \todo wait for child process to exit */
}

/**
 * \brief Fork and exec a process, and close fds
 * \param[in] path Path to executable
 * \param[in] args Arguments to pass to executable (optional)
 * \param[in] fds Vector of file descriptors to keep open (optional)
 *
 * Fork a process, and exec the executable specified by path. Prior to
 * exec'ing, but after forking, all file descriptors except for those
 * specified in fds will be closed.
 *
 * All indexes of args will be incremented by 1 before being fed to exec(),
 * so args[0] should not need to be equal to path.
 *
 * \return Zero on successful fork, exec, and closing the file descriptors,
 * or a negative error code otherwise
 */
int Process::start(const std::string &path,
		   const std::vector<std::string> &args,
		   const std::vector<int> &fds)
{
	int ret;

	if (running_)
		return 0;

	int childPid = fork();
	if (childPid == -1) {
		ret = -errno;
		LOG(Process, Error) << "Failed to fork: " << strerror(-ret);
		return ret;
	} else if (childPid) {
		pid_ = childPid;
		ProcessManager::instance()->registerProcess(this);

		running_ = true;

		return 0;
	} else {
		if (isolate())
			_exit(EXIT_FAILURE);

		closeAllFdsExcept(fds);

		const char *file = utils::secure_getenv("LIBCAMERA_LOG_FILE");
		if (file && strcmp(file, "syslog"))
			unsetenv("LIBCAMERA_LOG_FILE");

		const char **argv = new const char *[args.size() + 2];
		unsigned int len = args.size();
		argv[0] = path.c_str();
		for (unsigned int i = 0; i < len; i++)
			argv[i + 1] = args[i].c_str();
		argv[len + 1] = nullptr;

		execv(path.c_str(), (char **)argv);

		exit(EXIT_FAILURE);
	}
}

void Process::closeAllFdsExcept(const std::vector<int> &fds)
{
	std::vector<int> v(fds);
	sort(v.begin(), v.end());

	DIR *dir = opendir("/proc/self/fd");
	if (!dir)
		return;

	int dfd = dirfd(dir);

	struct dirent *ent;
	while ((ent = readdir(dir)) != nullptr) {
		char *endp;
		int fd = strtoul(ent->d_name, &endp, 10);
		if (*endp)
			continue;

		if (fd >= 0 && fd != dfd &&
		    !std::binary_search(v.begin(), v.end(), fd))
			close(fd);
	}

	closedir(dir);
}

int Process::isolate()
{
	int ret = unshare(CLONE_NEWUSER | CLONE_NEWNET);
	if (ret) {
		ret = -errno;
		LOG(Process, Error) << "Failed to unshare execution context: "
				    << strerror(-ret);
		return ret;
	}

	return 0;
}

/**
 * \brief SIGCHLD handler
 * \param[in] wstatus The status as output by waitpid()
 *
 * This function is called when the process associated with Process terminates.
 * It emits the Process::finished signal.
 */
void Process::died(int wstatus)
{
	running_ = false;
	exitStatus_ = WIFEXITED(wstatus) ? NormalExit : SignalExit;
	exitCode_ = exitStatus_ == NormalExit ? WEXITSTATUS(wstatus) : -1;

	finished.emit(exitStatus_, exitCode_);
}

/**
 * \fn Process::exitStatus()
 * \brief Retrieve the exit status of the process
 *
 * Return the exit status of the process, that is, whether the process