ipc_server.h

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// Copyright 2020-2023, Collabora, Ltd.
// SPDX-License-Identifier: BSL-1.0
/*!
 * @file
 * @brief  Common server side code.
 * @author Pete Black <pblack@collabora.com>
 * @author Jakob Bornecrantz <jakob@collabora.com>
 * @author Rylie Pavlik <rylie.pavlik@collabora.com>
 * @ingroup ipc_server
 */
 
#pragma once
 
#include "xrt/xrt_compiler.h"
#include "xrt/xrt_system.h"
#include "xrt/xrt_space.h"
 
#include "os/os_threading.h"
 
#include "util/u_logging.h"
 
#include "shared/ipc_protocol.h"
#include "shared/ipc_message_channel.h"
 
#include <stdio.h>
 
 
#ifdef __cplusplus
extern "C" {
#endif
 
/*
 *
 * Logging
 *
 */
 
#define IPC_TRACE(d, ...) U_LOG_IFL_T(d->log_level, __VA_ARGS__)
#define IPC_DEBUG(d, ...) U_LOG_IFL_D(d->log_level, __VA_ARGS__)
#define IPC_INFO(d, ...) U_LOG_IFL_I(d->log_level, __VA_ARGS__)
#define IPC_WARN(d, ...) U_LOG_IFL_W(d->log_level, __VA_ARGS__)
#define IPC_ERROR(d, ...) U_LOG_IFL_E(d->log_level, __VA_ARGS__)
 
 
/*
 *
 * Structs
 *
 */
 
#define IPC_MAX_CLIENT_SEMAPHORES 8
#define IPC_MAX_CLIENT_SWAPCHAINS 32
#define IPC_MAX_CLIENT_SPACES 128
 
struct xrt_instance;
struct xrt_compositor;
struct xrt_compositor_native;
 
 
/*!
 * Information about a single swapchain.
 *
 * @ingroup ipc_server
 */
struct ipc_swapchain_data
{
        uint32_t width;
        uint32_t height;
        uint64_t format;
        uint32_t image_count;
 
        bool active;
};
 
/*!
 * Holds the state for a single client.
 *
 * @ingroup ipc_server
 */
struct ipc_client_state
{
        //! Link back to the main server.
        struct ipc_server *server;
 
        //! Session for this client.
        struct xrt_session *xs;
 
        //! Compositor for this client.
        struct xrt_compositor *xc;
 
        //! Is the inputs and outputs active.
        bool io_active;
 
        //! Number of swapchains in use by client
        uint32_t swapchain_count;
 
        //! Ptrs to the swapchains
        struct xrt_swapchain *xscs[IPC_MAX_CLIENT_SWAPCHAINS];
 
        //! Data for the swapchains.
        struct ipc_swapchain_data swapchain_data[IPC_MAX_CLIENT_SWAPCHAINS];
 
        //! Number of compositor semaphores in use by client
        uint32_t compositor_semaphore_count;
 
        //! Ptrs to the semaphores.
        struct xrt_compositor_semaphore *xcsems[IPC_MAX_CLIENT_SEMAPHORES];
 
        struct
        {
                uint32_t root;
                uint32_t local;
                uint32_t stage;
                uint32_t unbounded;
        } semantic_spaces;
 
        //! Number of spaces.
        uint32_t space_count;
 
        //! Ptrs to the spaces.
        struct xrt_space *xspcs[IPC_MAX_CLIENT_SPACES];
 
        //! Which of the references spaces is the client using.
        bool ref_space_used[XRT_SPACE_REFERENCE_TYPE_COUNT];
 
        //! Socket fd used for client comms
        struct ipc_message_channel imc;
 
        struct ipc_app_state client_state;
 
        int server_thread_index;
};
 
enum ipc_thread_state
{
        IPC_THREAD_READY,
        IPC_THREAD_STARTING,
        IPC_THREAD_RUNNING,
        IPC_THREAD_STOPPING,
};
 
struct ipc_thread
{
        struct os_thread thread;
        volatile enum ipc_thread_state state;
        volatile struct ipc_client_state ics;
};
 
 
/*!
 *
 */
struct ipc_device
{
        //! The actual device.
        struct xrt_device *xdev;
 
        //! Is the IO suppressed for this device.
        bool io_active;
};
 
/*!
 * Platform-specific mainloop object for the IPC server.
 *
 * Contents are essentially implementation details, but are listed in full here so they may be included by value in the
 * main ipc_server struct.
 *
 * @see ipc_design
 *
 * @ingroup ipc_server
 */
struct ipc_server_mainloop
{
 
#if defined(XRT_OS_ANDROID) || defined(XRT_OS_LINUX) || defined(XRT_DOXYGEN)
        //! For waiting on various events in the main thread.
        int epoll_fd;
#endif
 
#if defined(XRT_OS_ANDROID) || defined(XRT_DOXYGEN)
        /*!
         * @name Android Mainloop Members
         * @{
         */
 
        //! File descriptor for the read end of our pipe for submitting new clients
        int pipe_read;
 
        /*!
         * File descriptor for the write end of our pipe for submitting new clients
         *
         * Must hold client_push_mutex while writing.
         */
        int pipe_write;
 
        /*!
         * Mutex for being able to register oneself as a new client.
         *
         * Locked only by threads in `ipc_server_mainloop_add_fd()`.
         *
         * This must be locked first, and kept locked the entire time a client is attempting to register and wait for
         * confirmation. It ensures no acknowledgements of acceptance are lost and moves the overhead of ensuring this
         * to the client thread.
         */
        pthread_mutex_t client_push_mutex;
 
 
        /*!
         * The last client fd we accepted, to acknowledge client acceptance.
         *
         * Also used as a sentinel during shutdown.
         *
         * Must hold accept_mutex while writing.
         */
        int last_accepted_fd;
 
        /*!
         * Condition variable for accepting clients.
         *
         * Signalled when @ref last_accepted_fd is updated.
         *
         * Associated with @ref accept_mutex
         */
        pthread_cond_t accept_cond;
 
        /*!
         * Mutex for accepting clients.
         *
         * Locked by both clients and server: that is, by threads in `ipc_server_mainloop_add_fd()` and in the
         * server/compositor thread in an implementation function called from `ipc_server_mainloop_poll()`.
         *
         * Exists to operate in conjunction with @ref accept_cond - it exists to make sure that the client can be woken
         * when the server accepts it.
         */
        pthread_mutex_t accept_mutex;
 
 
        /*! @} */
#define XRT_IPC_GOT_IMPL
#endif
 
#if (defined(XRT_OS_LINUX) && !defined(XRT_OS_ANDROID)) || defined(XRT_DOXYGEN)
        /*!
         * @name Desktop Linux Mainloop Members
         * @{
         */
 
        //! Socket that we accept connections on.
        int listen_socket;
 
        //! Were we launched by socket activation, instead of explicitly?
        bool launched_by_socket;
 
        //! The socket filename we bound to, if any.
        char *socket_filename;
 
        /*! @} */
 
#define XRT_IPC_GOT_IMPL
#endif
 
#if defined(XRT_OS_WINDOWS) || defined(XRT_DOXYGEN)
        /*!
         * @name Desktop Windows Mainloop Members
         * @{
         */
 
        //! Named Pipe that we accept connections on.
        HANDLE pipe_handle;
 
        //! Name of the Pipe that we accept connections on.
        char *pipe_name;
 
        /*! @} */
 
#define XRT_IPC_GOT_IMPL
#endif
 
#ifndef XRT_IPC_GOT_IMPL
#error "Need port"
#endif
};
 
/*!
 * De-initialize the mainloop object.
 * @public @memberof ipc_server_mainloop
 */
void
ipc_server_mainloop_deinit(struct ipc_server_mainloop *ml);
 
/*!
 * Initialize the mainloop object.
 *
 * @return <0 on error.
 * @public @memberof ipc_server_mainloop
 */
int
ipc_server_mainloop_init(struct ipc_server_mainloop *ml);
 
/*!
 * @brief Poll the mainloop.
 *
 * Any errors are signalled by calling ipc_server_handle_failure()
 * @public @memberof ipc_server_mainloop
 */
void
ipc_server_mainloop_poll(struct ipc_server *vs, struct ipc_server_mainloop *ml);
 
/*!
 * Main IPC object for the server.
 *
 * @ingroup ipc_server
 */
struct ipc_server
{
        struct xrt_instance *xinst;
 
        //! Handle for the current process, e.g. pidfile on linux
        struct u_process *process;
 
        struct u_debug_gui *debug_gui;
 
        //! The @ref xrt_iface level system.
        struct xrt_system *xsys;
 
        //! System devices.
        struct xrt_system_devices *xsysd;
 
        //! Space overseer.
        struct xrt_space_overseer *xso;
 
        //! System compositor.
        struct xrt_system_compositor *xsysc;
 
        struct ipc_device idevs[XRT_SYSTEM_MAX_DEVICES];
        struct xrt_tracking_origin *xtracks[XRT_SYSTEM_MAX_DEVICES];
 
        struct ipc_shared_memory *ism;
        xrt_shmem_handle_t ism_handle;
 
        struct ipc_server_mainloop ml;
 
        // Is the mainloop supposed to run.
        volatile bool running;
 
        // Should we exit when a client disconnects.
        bool exit_on_disconnect;
 
        enum u_logging_level log_level;
 
        struct ipc_thread threads[IPC_MAX_CLIENTS];
 
        volatile uint32_t current_slot_index;
 
        //! Generator for IDs.
        uint32_t id_generator;
 
        struct
        {
                int active_client_index;
                int last_active_client_index;
 
                struct os_mutex lock;
        } global_state;
};
 
 
/*!
 * Get the current state of a client.
 *
 * @ingroup ipc_server
 */
xrt_result_t
ipc_server_get_client_app_state(struct ipc_server *s, uint32_t client_id, struct ipc_app_state *out_ias);
 
/*!
 * Set the new active client.
 *
 * @ingroup ipc_server
 */
xrt_result_t
ipc_server_set_active_client(struct ipc_server *s, uint32_t client_id);
 
/*!
 * Toggle the io for this client.
 *
 * @ingroup ipc_server
 */
xrt_result_t
ipc_server_toggle_io_client(struct ipc_server *s, uint32_t client_id);
 
/*!
 * Called by client threads to set a session to active.
 *
 * @ingroup ipc_server
 */
void
ipc_server_activate_session(volatile struct ipc_client_state *ics);
 
/*!
 * Called by client threads to set a session to deactivate.
 *
 * @ingroup ipc_server
 */
void
ipc_server_deactivate_session(volatile struct ipc_client_state *ics);
 
/*!
 * Called by client threads to recalculate active client.
 *
 * @ingroup ipc_server
 */
void
ipc_server_update_state(struct ipc_server *s);
 
/*!
 * Thread function for the client side dispatching.
 *
 * @ingroup ipc_server
 */
void *
ipc_server_client_thread(void *_ics);
 
/*!
 * This destroys the native compositor for this client and any extra objects
 * created from it, like all of the swapchains.
 */
void
ipc_server_client_destroy_session_and_compositor(volatile struct ipc_client_state *ics);
 
/*!
 * @defgroup ipc_server_internals Server Internals
 * @brief These are only called by the platform-specific mainloop polling code.
 * @ingroup ipc_server
 * @{
 */
/*!
 * Called when a client has connected, it takes the client's ipc handle.
 * Handles all things needed to be done for a client connecting, like starting
 * it's thread.
 *
 * @param vs         The IPC server.
 * @param ipc_handle Handle to communicate over.
 * @memberof ipc_server
 */
void
ipc_server_handle_client_connected(struct ipc_server *vs, xrt_ipc_handle_t ipc_handle);
 
/*!
 * Perform whatever needs to be done when the mainloop polling encounters a failure.
 * @memberof ipc_server
 */
void
ipc_server_handle_failure(struct ipc_server *vs);
 
/*!
 * Perform whatever needs to be done when the mainloop polling identifies that the server should be shut down.
 *
 * Does something like setting a flag or otherwise signalling for shutdown: does not itself explicitly exit.
 * @memberof ipc_server
 */
void
ipc_server_handle_shutdown_signal(struct ipc_server *vs);
 
xrt_result_t
ipc_server_get_system_properties(struct ipc_server *vs, struct xrt_system_properties *out_properties);
//! @}
 
/*
 *
 * Helpers
 *
 */
 
/*!
 * Get a xdev with the given device_id.
 */
static inline struct xrt_device *
get_xdev(volatile struct ipc_client_state *ics, uint32_t device_id)
{
        return ics->server->idevs[device_id].xdev;
}
 
/*!
 * Get a idev with the given device_id.
 */
static inline struct ipc_device *
get_idev(volatile struct ipc_client_state *ics, uint32_t device_id)
{
        return &ics->server->idevs[device_id];
}
 
 
#ifdef __cplusplus
}
#endif