diff options
| -rw-r--r-- | src/libcamera/include/ipc_unixsocket.h | 2 | ||||
| -rw-r--r-- | src/libcamera/ipc_unixsocket.cpp | 88 |
2 files changed, 63 insertions, 27 deletions
diff --git a/src/libcamera/include/ipc_unixsocket.h b/src/libcamera/include/ipc_unixsocket.h index ef166d74..03e9fe49 100644 --- a/src/libcamera/include/ipc_unixsocket.h +++ b/src/libcamera/include/ipc_unixsocket.h @@ -49,6 +49,8 @@ private: void dataNotifier(EventNotifier *notifier); int fd_; + bool headerReceived_; + struct Header header_; EventNotifier *notifier_; }; diff --git a/src/libcamera/ipc_unixsocket.cpp b/src/libcamera/ipc_unixsocket.cpp index c11f1160..def08eef 100644 --- a/src/libcamera/ipc_unixsocket.cpp +++ b/src/libcamera/ipc_unixsocket.cpp @@ -7,6 +7,7 @@ #include "ipc_unixsocket.h" +#include <poll.h> #include <string.h> #include <sys/socket.h> #include <unistd.h> @@ -49,10 +50,10 @@ LOG_DEFINE_CATEGORY(IPCUnixSocket) * transporting entire payloads with guaranteed ordering. * * The IPC design is asynchronous, a message is queued to a receiver which gets - * notified that a message is ready to be consumed by a signal. The queuer of - * the message gets no notification when a message is delivered nor processed. - * If such interactions are needed a protocol specific to the users use-case - * should be implemented on top of the IPC objects. + * notified that a message is ready to be consumed by the \ref readyRead + * signal. The sender of the message gets no notification when a message is + * delivered nor processed. If such interactions are needed a protocol specific + * to the users use-case should be implemented on top of the IPC objects. * * Establishment of an IPC channel is asymmetrical. The side that initiates * communication first instantiates a local side socket and creates the channel @@ -64,7 +65,7 @@ LOG_DEFINE_CATEGORY(IPCUnixSocket) */ IPCUnixSocket::IPCUnixSocket() - : fd_(-1), notifier_(nullptr) + : fd_(-1), headerReceived_(false), notifier_(nullptr) { } @@ -89,7 +90,7 @@ int IPCUnixSocket::create() int sockets[2]; int ret; - ret = socketpair(AF_UNIX, SOCK_DGRAM, 0, sockets); + ret = socketpair(AF_UNIX, SOCK_DGRAM | SOCK_NONBLOCK, 0, sockets); if (ret) { ret = -errno; LOG(IPCUnixSocket, Error) @@ -142,6 +143,7 @@ void IPCUnixSocket::close() ::close(fd_); fd_ = -1; + headerReceived_ = false; } /** @@ -193,38 +195,38 @@ int IPCUnixSocket::send(const Payload &payload) * \param[out] payload Payload where to write the received message * * This method receives the message payload from the IPC channel and writes it - * to the \a payload. It blocks until one message is received, if an - * asynchronous behavior is desired this method should be called when the - * readyRead signal is emitted. + * to the \a payload. If no message payload is available, it returns + * immediately with -EAGAIN. The \ref readyRead signal shall be used to receive + * notification of message availability. * * \todo Add state machine to make sure we don't block forever and that * a header is always followed by a payload. * * \return 0 on success or a negative error code otherwise + * \retval -EAGAIN No message payload is available + * \retval -ENOTCONN The socket is not connected (neither create() nor bind() + * has been called) */ int IPCUnixSocket::receive(Payload *payload) { - Header hdr; - int ret; - if (!isBound()) return -ENOTCONN; - if (!payload) - return -EINVAL; + if (!headerReceived_) + return -EAGAIN; - ret = ::recv(fd_, &hdr, sizeof(hdr), 0); - if (ret < 0) { - ret = -errno; - LOG(IPCUnixSocket, Error) - << "Failed to recv header: " << strerror(-ret); + payload->data.resize(header_.data); + payload->fds.resize(header_.fds); + + int ret = recvData(payload->data.data(), header_.data, + payload->fds.data(), header_.fds); + if (ret < 0) return ret; - } - payload->data.resize(hdr.data); - payload->fds.resize(hdr.fds); + headerReceived_ = false; + notifier_->setEnabled(true); - return recvData(payload->data.data(), hdr.data, payload->fds.data(), hdr.fds); + return 0; } /** @@ -232,7 +234,8 @@ int IPCUnixSocket::receive(Payload *payload) * \brief A Signal emitted when a message is ready to be read */ -int IPCUnixSocket::sendData(const void *buffer, size_t length, const int32_t *fds, unsigned int num) +int IPCUnixSocket::sendData(const void *buffer, size_t length, + const int32_t *fds, unsigned int num) { struct iovec iov[1]; iov[0].iov_base = const_cast<void *>(buffer); @@ -266,7 +269,8 @@ int IPCUnixSocket::sendData(const void *buffer, size_t length, const int32_t *fd return 0; } -int IPCUnixSocket::recvData(void *buffer, size_t length, int32_t *fds, unsigned int num) +int IPCUnixSocket::recvData(void *buffer, size_t length, + int32_t *fds, unsigned int num) { struct iovec iov[1]; iov[0].iov_base = buffer; @@ -291,8 +295,9 @@ int IPCUnixSocket::recvData(void *buffer, size_t length, int32_t *fds, unsigned if (recvmsg(fd_, &msg, 0) < 0) { int ret = -errno; - LOG(IPCUnixSocket, Error) - << "Failed to recvmsg: " << strerror(-ret); + if (ret != -EAGAIN) + LOG(IPCUnixSocket, Error) + << "Failed to recvmsg: " << strerror(-ret); return ret; } @@ -303,6 +308,35 @@ int IPCUnixSocket::recvData(void *buffer, size_t length, int32_t *fds, unsigned void IPCUnixSocket::dataNotifier(EventNotifier *notifier) { + int ret; + + if (!headerReceived_) { + /* Receive the header. */ + ret = ::recv(fd_, &header_, sizeof(header_), 0); + if (ret < 0) { + ret = -errno; + LOG(IPCUnixSocket, Error) + << "Failed to receive header: " << strerror(-ret); + return; + } + + headerReceived_ = true; + } + + /* + * If the payload has arrived, disable the notifier and emit the + * readyRead signal. The notifier will be reenabled by the receive() + * method. + */ + struct pollfd fds = { fd_, POLLIN, 0 }; + ret = poll(&fds, 1, 0); + if (ret < 0) + return; + + if (!(fds.revents & POLLIN)) + return; + + notifier_->setEnabled(false); readyRead.emit(this); } |