From 59c7b88198af8af29deffb2eee7b7b2329e9197e Mon Sep 17 00:00:00 2001 From: Jeff Hostetler Date: Mon, 15 Mar 2021 21:08:23 +0000 Subject: simple-ipc: add win32 implementation Create Windows implementation of "simple-ipc" using named pipes. Signed-off-by: Jeff Hostetler Signed-off-by: Junio C Hamano --- simple-ipc.h | 228 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 228 insertions(+) create mode 100644 simple-ipc.h (limited to 'simple-ipc.h') diff --git a/simple-ipc.h b/simple-ipc.h new file mode 100644 index 0000000000..ab5619e3d7 --- /dev/null +++ b/simple-ipc.h @@ -0,0 +1,228 @@ +#ifndef GIT_SIMPLE_IPC_H +#define GIT_SIMPLE_IPC_H + +/* + * See Documentation/technical/api-simple-ipc.txt + */ + +#if defined(GIT_WINDOWS_NATIVE) +#define SUPPORTS_SIMPLE_IPC +#endif + +#ifdef SUPPORTS_SIMPLE_IPC +#include "pkt-line.h" + +/* + * Simple IPC Client Side API. + */ + +enum ipc_active_state { + /* + * The pipe/socket exists and the daemon is waiting for connections. + */ + IPC_STATE__LISTENING = 0, + + /* + * The pipe/socket exists, but the daemon is not listening. + * Perhaps it is very busy. + * Perhaps the daemon died without deleting the path. + * Perhaps it is shutting down and draining existing clients. + * Perhaps it is dead, but other clients are lingering and + * still holding a reference to the pathname. + */ + IPC_STATE__NOT_LISTENING, + + /* + * The requested pathname is bogus and no amount of retries + * will fix that. + */ + IPC_STATE__INVALID_PATH, + + /* + * The requested pathname is not found. This usually means + * that there is no daemon present. + */ + IPC_STATE__PATH_NOT_FOUND, + + IPC_STATE__OTHER_ERROR, +}; + +struct ipc_client_connect_options { + /* + * Spin under timeout if the server is running but can't + * accept our connection yet. This should always be set + * unless you just want to poke the server and see if it + * is alive. + */ + unsigned int wait_if_busy:1; + + /* + * Spin under timeout if the pipe/socket is not yet present + * on the file system. This is useful if we just started + * the service and need to wait for it to become ready. + */ + unsigned int wait_if_not_found:1; +}; + +#define IPC_CLIENT_CONNECT_OPTIONS_INIT { \ + .wait_if_busy = 0, \ + .wait_if_not_found = 0, \ +} + +/* + * Determine if a server is listening on this named pipe or socket using + * platform-specific logic. This might just probe the filesystem or it + * might make a trivial connection to the server using this pathname. + */ +enum ipc_active_state ipc_get_active_state(const char *path); + +struct ipc_client_connection { + int fd; +}; + +/* + * Try to connect to the daemon on the named pipe or socket. + * + * Returns IPC_STATE__LISTENING and a connection handle. + * + * Otherwise, returns info to help decide whether to retry or to + * spawn/respawn the server. + */ +enum ipc_active_state ipc_client_try_connect( + const char *path, + const struct ipc_client_connect_options *options, + struct ipc_client_connection **p_connection); + +void ipc_client_close_connection(struct ipc_client_connection *connection); + +/* + * Used by the client to synchronously send and receive a message with + * the server on the provided client connection. + * + * Returns 0 when successful. + * + * Calls error() and returns non-zero otherwise. + */ +int ipc_client_send_command_to_connection( + struct ipc_client_connection *connection, + const char *message, struct strbuf *answer); + +/* + * Used by the client to synchronously connect and send and receive a + * message to the server listening at the given path. + * + * Returns 0 when successful. + * + * Calls error() and returns non-zero otherwise. + */ +int ipc_client_send_command(const char *path, + const struct ipc_client_connect_options *options, + const char *message, struct strbuf *answer); + +/* + * Simple IPC Server Side API. + */ + +struct ipc_server_reply_data; + +typedef int (ipc_server_reply_cb)(struct ipc_server_reply_data *, + const char *response, + size_t response_len); + +/* + * Prototype for an application-supplied callback to process incoming + * client IPC messages and compose a reply. The `application_cb` should + * use the provided `reply_cb` and `reply_data` to send an IPC response + * back to the client. The `reply_cb` callback can be called multiple + * times for chunking purposes. A reply message is optional and may be + * omitted if not necessary for the application. + * + * The return value from the application callback is ignored. + * The value `SIMPLE_IPC_QUIT` can be used to shutdown the server. + */ +typedef int (ipc_server_application_cb)(void *application_data, + const char *request, + ipc_server_reply_cb *reply_cb, + struct ipc_server_reply_data *reply_data); + +#define SIMPLE_IPC_QUIT -2 + +/* + * Opaque instance data to represent an IPC server instance. + */ +struct ipc_server_data; + +/* + * Control parameters for the IPC server instance. + * Use this to hide platform-specific settings. + */ +struct ipc_server_opts +{ + int nr_threads; +}; + +/* + * Start an IPC server instance in one or more background threads + * and return a handle to the pool. + * + * Returns 0 if the asynchronous server pool was started successfully. + * Returns -1 if not. + * Returns -2 if we could not startup because another server is using + * the socket or named pipe. + * + * When a client IPC message is received, the `application_cb` will be + * called (possibly on a random thread) to handle the message and + * optionally compose a reply message. + */ +int ipc_server_run_async(struct ipc_server_data **returned_server_data, + const char *path, const struct ipc_server_opts *opts, + ipc_server_application_cb *application_cb, + void *application_data); + +/* + * Gently signal the IPC server pool to shutdown. No new client + * connections will be accepted, but existing connections will be + * allowed to complete. + */ +int ipc_server_stop_async(struct ipc_server_data *server_data); + +/* + * Block the calling thread until all threads in the IPC server pool + * have completed and been joined. + */ +int ipc_server_await(struct ipc_server_data *server_data); + +/* + * Close and free all resource handles associated with the IPC server + * pool. + */ +void ipc_server_free(struct ipc_server_data *server_data); + +/* + * Run an IPC server instance and block the calling thread of the + * current process. It does not return until the IPC server has + * either shutdown or had an unrecoverable error. + * + * The IPC server handles incoming IPC messages from client processes + * and may use one or more background threads as necessary. + * + * Returns 0 after the server has completed successfully. + * Returns -1 if the server cannot be started. + * Returns -2 if we could not startup because another server is using + * the socket or named pipe. + * + * When a client IPC message is received, the `application_cb` will be + * called (possibly on a random thread) to handle the message and + * optionally compose a reply message. + * + * Note that `ipc_server_run()` is a synchronous wrapper around the + * above asynchronous routines. It effectively hides all of the + * server state and thread details from the caller and presents a + * simple synchronous interface. + */ +int ipc_server_run(const char *path, const struct ipc_server_opts *opts, + ipc_server_application_cb *application_cb, + void *application_data); + +#endif /* SUPPORTS_SIMPLE_IPC */ +#endif /* GIT_SIMPLE_IPC_H */ -- cgit v1.2.3