libcamera: Add IPCPipe implementation based on unix socket

Add an implementation of IPCPipe using unix socket.

[Original patch]
Signed-off-by: Paul Elder <paul.elder@ideasonboard.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
[Error fix from Niklas]
Signed-off-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
Reviewed-by: Paul Elder <paul.elder@ideasonboard.com>

src/libcamera/ipc_pipe_unixsocket.cpp

@@ -0,0 +1,144 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2020, Google Inc.
+ *
+ * ipc_pipe_unixsocket.cpp - Image Processing Algorithm IPC module using unix socket
+ */
+
+#include "libcamera/internal/ipc_pipe_unixsocket.h"
+
+#include <vector>
+
+#include "libcamera/internal/event_dispatcher.h"
+#include "libcamera/internal/ipc_pipe.h"
+#include "libcamera/internal/ipc_unixsocket.h"
+#include "libcamera/internal/log.h"
+#include "libcamera/internal/process.h"
+#include "libcamera/internal/thread.h"
+#include "libcamera/internal/timer.h"
+
+namespace libcamera {
+
+LOG_DECLARE_CATEGORY(IPCPipe)
+
+IPCPipeUnixSocket::IPCPipeUnixSocket(const char *ipaModulePath,
+				     const char *ipaProxyWorkerPath)
+	: IPCPipe()
+{
+	std::vector<int> fds;
+	std::vector<std::string> args;
+	args.push_back(ipaModulePath);
+
+	socket_ = std::make_unique<IPCUnixSocket>();
+	int fd = socket_->create();
+	if (fd < 0) {
+		LOG(IPCPipe, Error) << "Failed to create socket";
+		return;
+	}
+	socket_->readyRead.connect(this, &IPCPipeUnixSocket::readyRead);
+	args.push_back(std::to_string(fd));
+	fds.push_back(fd);
+
+	proc_ = std::make_unique<Process>();
+	int ret = proc_->start(ipaProxyWorkerPath, args, fds);
+	if (ret) {
+		LOG(IPCPipe, Error)
+			<< "Failed to start proxy worker process";
+		return;
+	}
+
+	connected_ = true;
+}
+
+IPCPipeUnixSocket::~IPCPipeUnixSocket()
+{
+}
+
+int IPCPipeUnixSocket::sendSync(const IPCMessage &in, IPCMessage *out)
+{
+	IPCUnixSocket::Payload response;
+
+	int ret = call(in.payload(), &response, in.header().cookie);
+	if (ret) {
+		LOG(IPCPipe, Error) << "Failed to call sync";
+		return ret;
+	}
+
+	if (out)
+		*out = IPCMessage(response);
+
+	return 0;
+}
+
+int IPCPipeUnixSocket::sendAsync(const IPCMessage &data)
+{
+	int ret = socket_->send(data.payload());
+	if (ret) {
+		LOG(IPCPipe, Error) << "Failed to call async";
+		return ret;
+	}
+
+	return 0;
+}
+
+void IPCPipeUnixSocket::readyRead(IPCUnixSocket *socket)
+{
+	IPCUnixSocket::Payload payload;
+	int ret = socket->receive(&payload);
+	if (ret) {
+		LOG(IPCPipe, Error) << "Receive message failed" << ret;
+		return;
+	}
+
+	/* \todo Use span to avoid the double copy when callData is found. */
+	if (payload.data.size() < sizeof(IPCMessage::Header)) {
+		LOG(IPCPipe, Error) << "Not enough data received";
+		return;
+	}
+
+	IPCMessage ipcMessage(payload);
+
+	auto callData = callData_.find(ipcMessage.header().cookie);
+	if (callData != callData_.end()) {
+		*callData->second.response = std::move(payload);
+		callData->second.done = true;
+		return;
+	}
+
+	/* Received unexpected data, this means it's a call from the IPA. */
+	recv.emit(ipcMessage);
+}
+
+int IPCPipeUnixSocket::call(const IPCUnixSocket::Payload &message,
+			    IPCUnixSocket::Payload *response, uint32_t cookie)
+{
+	Timer timeout;
+	int ret;
+
+	const auto result = callData_.insert({ cookie, { response, false } });
+	const auto &iter = result.first;
+
+	ret = socket_->send(message);
+	if (ret) {
+		callData_.erase(iter);
+		return ret;
+	}
+
+	/* \todo Make this less dangerous, see IPCPipe::sendSync() */
+	timeout.start(2000);
+	while (!iter->second.done) {
+		if (!timeout.isRunning()) {
+			LOG(IPCPipe, Error) << "Call timeout!";
+			callData_.erase(iter);
+			return -ETIMEDOUT;
+		}
+
+		Thread::current()->eventDispatcher()->processEvents();
+	}
+
+	callData_.erase(iter);
+
+	return 0;
+}
+
+} /* namespace libcamera */

src/libcamera/meson.build

@@ -32,6 +32,7 @@ libcamera_sources = files([
     'ipa_module.cpp',
     'ipa_proxy.cpp',
     'ipc_pipe.cpp',
+    'ipc_pipe_unixsocket.cpp',
     'ipc_unixsocket.cpp',
     'log.cpp',
     'media_device.cpp',