--- /dev/null
+#include "cache.h"
+#include "simple-ipc.h"
+#include "strbuf.h"
+#include "pkt-line.h"
+#include "thread-utils.h"
+
+#ifndef GIT_WINDOWS_NATIVE
+#error This file can only be compiled on Windows
+#endif
+
+static int initialize_pipe_name(const char *path, wchar_t *wpath, size_t alloc)
+{
+ int off = 0;
+ struct strbuf realpath = STRBUF_INIT;
+
+ if (!strbuf_realpath(&realpath, path, 0))
+ return -1;
+
+ off = swprintf(wpath, alloc, L"\\\\.\\pipe\\");
+ if (xutftowcs(wpath + off, realpath.buf, alloc - off) < 0)
+ return -1;
+
+ /* Handle drive prefix */
+ if (wpath[off] && wpath[off + 1] == L':') {
+ wpath[off + 1] = L'_';
+ off += 2;
+ }
+
+ for (; wpath[off]; off++)
+ if (wpath[off] == L'/')
+ wpath[off] = L'\\';
+
+ strbuf_release(&realpath);
+ return 0;
+}
+
+static enum ipc_active_state get_active_state(wchar_t *pipe_path)
+{
+ if (WaitNamedPipeW(pipe_path, NMPWAIT_USE_DEFAULT_WAIT))
+ return IPC_STATE__LISTENING;
+
+ if (GetLastError() == ERROR_SEM_TIMEOUT)
+ return IPC_STATE__NOT_LISTENING;
+
+ if (GetLastError() == ERROR_FILE_NOT_FOUND)
+ return IPC_STATE__PATH_NOT_FOUND;
+
+ return IPC_STATE__OTHER_ERROR;
+}
+
+enum ipc_active_state ipc_get_active_state(const char *path)
+{
+ wchar_t pipe_path[MAX_PATH];
+
+ if (initialize_pipe_name(path, pipe_path, ARRAY_SIZE(pipe_path)) < 0)
+ return IPC_STATE__INVALID_PATH;
+
+ return get_active_state(pipe_path);
+}
+
+#define WAIT_STEP_MS (50)
+
+static enum ipc_active_state connect_to_server(
+ const wchar_t *wpath,
+ DWORD timeout_ms,
+ const struct ipc_client_connect_options *options,
+ int *pfd)
+{
+ DWORD t_start_ms, t_waited_ms;
+ DWORD step_ms;
+ HANDLE hPipe = INVALID_HANDLE_VALUE;
+ DWORD mode = PIPE_READMODE_BYTE;
+ DWORD gle;
+
+ *pfd = -1;
+
+ for (;;) {
+ hPipe = CreateFileW(wpath, GENERIC_READ | GENERIC_WRITE,
+ 0, NULL, OPEN_EXISTING, 0, NULL);
+ if (hPipe != INVALID_HANDLE_VALUE)
+ break;
+
+ gle = GetLastError();
+
+ switch (gle) {
+ case ERROR_FILE_NOT_FOUND:
+ if (!options->wait_if_not_found)
+ return IPC_STATE__PATH_NOT_FOUND;
+ if (!timeout_ms)
+ return IPC_STATE__PATH_NOT_FOUND;
+
+ step_ms = (timeout_ms < WAIT_STEP_MS) ?
+ timeout_ms : WAIT_STEP_MS;
+ sleep_millisec(step_ms);
+
+ timeout_ms -= step_ms;
+ break; /* try again */
+
+ case ERROR_PIPE_BUSY:
+ if (!options->wait_if_busy)
+ return IPC_STATE__NOT_LISTENING;
+ if (!timeout_ms)
+ return IPC_STATE__NOT_LISTENING;
+
+ t_start_ms = (DWORD)(getnanotime() / 1000000);
+
+ if (!WaitNamedPipeW(wpath, timeout_ms)) {
+ if (GetLastError() == ERROR_SEM_TIMEOUT)
+ return IPC_STATE__NOT_LISTENING;
+
+ return IPC_STATE__OTHER_ERROR;
+ }
+
+ /*
+ * A pipe server instance became available.
+ * Race other client processes to connect to
+ * it.
+ *
+ * But first decrement our overall timeout so
+ * that we don't starve if we keep losing the
+ * race. But also guard against special
+ * NPMWAIT_ values (0 and -1).
+ */
+ t_waited_ms = (DWORD)(getnanotime() / 1000000) - t_start_ms;
+ if (t_waited_ms < timeout_ms)
+ timeout_ms -= t_waited_ms;
+ else
+ timeout_ms = 1;
+ break; /* try again */
+
+ default:
+ return IPC_STATE__OTHER_ERROR;
+ }
+ }
+
+ if (!SetNamedPipeHandleState(hPipe, &mode, NULL, NULL)) {
+ CloseHandle(hPipe);
+ return IPC_STATE__OTHER_ERROR;
+ }
+
+ *pfd = _open_osfhandle((intptr_t)hPipe, O_RDWR|O_BINARY);
+ if (*pfd < 0) {
+ CloseHandle(hPipe);
+ return IPC_STATE__OTHER_ERROR;
+ }
+
+ /* fd now owns hPipe */
+
+ return IPC_STATE__LISTENING;
+}
+
+/*
+ * The default connection timeout for Windows clients.
+ *
+ * This is not currently part of the ipc_ API (nor the config settings)
+ * because of differences between Windows and other platforms.
+ *
+ * This value was chosen at random.
+ */
+#define WINDOWS_CONNECTION_TIMEOUT_MS (30000)
+
+enum ipc_active_state ipc_client_try_connect(
+ const char *path,
+ const struct ipc_client_connect_options *options,
+ struct ipc_client_connection **p_connection)
+{
+ wchar_t wpath[MAX_PATH];
+ enum ipc_active_state state = IPC_STATE__OTHER_ERROR;
+ int fd = -1;
+
+ *p_connection = NULL;
+
+ trace2_region_enter("ipc-client", "try-connect", NULL);
+ trace2_data_string("ipc-client", NULL, "try-connect/path", path);
+
+ if (initialize_pipe_name(path, wpath, ARRAY_SIZE(wpath)) < 0)
+ state = IPC_STATE__INVALID_PATH;
+ else
+ state = connect_to_server(wpath, WINDOWS_CONNECTION_TIMEOUT_MS,
+ options, &fd);
+
+ trace2_data_intmax("ipc-client", NULL, "try-connect/state",
+ (intmax_t)state);
+ trace2_region_leave("ipc-client", "try-connect", NULL);
+
+ if (state == IPC_STATE__LISTENING) {
+ (*p_connection) = xcalloc(1, sizeof(struct ipc_client_connection));
+ (*p_connection)->fd = fd;
+ }
+
+ return state;
+}
+
+void ipc_client_close_connection(struct ipc_client_connection *connection)
+{
+ if (!connection)
+ return;
+
+ if (connection->fd != -1)
+ close(connection->fd);
+
+ free(connection);
+}
+
+int ipc_client_send_command_to_connection(
+ struct ipc_client_connection *connection,
+ const char *message, struct strbuf *answer)
+{
+ int ret = 0;
+
+ strbuf_setlen(answer, 0);
+
+ trace2_region_enter("ipc-client", "send-command", NULL);
+
+ if (write_packetized_from_buf_no_flush(message, strlen(message),
+ connection->fd) < 0 ||
+ packet_flush_gently(connection->fd) < 0) {
+ ret = error(_("could not send IPC command"));
+ goto done;
+ }
+
+ FlushFileBuffers((HANDLE)_get_osfhandle(connection->fd));
+
+ if (read_packetized_to_strbuf(
+ connection->fd, answer,
+ PACKET_READ_GENTLE_ON_EOF | PACKET_READ_GENTLE_ON_READ_ERROR) < 0) {
+ ret = error(_("could not read IPC response"));
+ goto done;
+ }
+
+done:
+ trace2_region_leave("ipc-client", "send-command", NULL);
+ return ret;
+}
+
+int ipc_client_send_command(const char *path,
+ const struct ipc_client_connect_options *options,
+ const char *message, struct strbuf *response)
+{
+ int ret = -1;
+ enum ipc_active_state state;
+ struct ipc_client_connection *connection = NULL;
+
+ state = ipc_client_try_connect(path, options, &connection);
+
+ if (state != IPC_STATE__LISTENING)
+ return ret;
+
+ ret = ipc_client_send_command_to_connection(connection, message, response);
+
+ ipc_client_close_connection(connection);
+
+ return ret;
+}
+
+/*
+ * Duplicate the given pipe handle and wrap it in a file descriptor so
+ * that we can use pkt-line on it.
+ */
+static int dup_fd_from_pipe(const HANDLE pipe)
+{
+ HANDLE process = GetCurrentProcess();
+ HANDLE handle;
+ int fd;
+
+ if (!DuplicateHandle(process, pipe, process, &handle, 0, FALSE,
+ DUPLICATE_SAME_ACCESS)) {
+ errno = err_win_to_posix(GetLastError());
+ return -1;
+ }
+
+ fd = _open_osfhandle((intptr_t)handle, O_RDWR|O_BINARY);
+ if (fd < 0) {
+ errno = err_win_to_posix(GetLastError());
+ CloseHandle(handle);
+ return -1;
+ }
+
+ /*
+ * `handle` is now owned by `fd` and will be automatically closed
+ * when the descriptor is closed.
+ */
+
+ return fd;
+}
+
+/*
+ * Magic numbers used to annotate callback instance data.
+ * These are used to help guard against accidentally passing the
+ * wrong instance data across multiple levels of callbacks (which
+ * is easy to do if there are `void*` arguments).
+ */
+enum magic {
+ MAGIC_SERVER_REPLY_DATA,
+ MAGIC_SERVER_THREAD_DATA,
+ MAGIC_SERVER_DATA,
+};
+
+struct ipc_server_reply_data {
+ enum magic magic;
+ int fd;
+ struct ipc_server_thread_data *server_thread_data;
+};
+
+struct ipc_server_thread_data {
+ enum magic magic;
+ struct ipc_server_thread_data *next_thread;
+ struct ipc_server_data *server_data;
+ pthread_t pthread_id;
+ HANDLE hPipe;
+};
+
+/*
+ * On Windows, the conceptual "ipc-server" is implemented as a pool of
+ * n idential/peer "server-thread" threads. That is, there is no
+ * hierarchy of threads; and therefore no controller thread managing
+ * the pool. Each thread has an independent handle to the named pipe,
+ * receives incoming connections, processes the client, and re-uses
+ * the pipe for the next client connection.
+ *
+ * Therefore, the "ipc-server" only needs to maintain a list of the
+ * spawned threads for eventual "join" purposes.
+ *
+ * A single "stop-event" is visible to all of the server threads to
+ * tell them to shutdown (when idle).
+ */
+struct ipc_server_data {
+ enum magic magic;
+ ipc_server_application_cb *application_cb;
+ void *application_data;
+ struct strbuf buf_path;
+ wchar_t wpath[MAX_PATH];
+
+ HANDLE hEventStopRequested;
+ struct ipc_server_thread_data *thread_list;
+ int is_stopped;
+};
+
+enum connect_result {
+ CR_CONNECTED = 0,
+ CR_CONNECT_PENDING,
+ CR_CONNECT_ERROR,
+ CR_WAIT_ERROR,
+ CR_SHUTDOWN,
+};
+
+static enum connect_result queue_overlapped_connect(
+ struct ipc_server_thread_data *server_thread_data,
+ OVERLAPPED *lpo)
+{
+ if (ConnectNamedPipe(server_thread_data->hPipe, lpo))
+ goto failed;
+
+ switch (GetLastError()) {
+ case ERROR_IO_PENDING:
+ return CR_CONNECT_PENDING;
+
+ case ERROR_PIPE_CONNECTED:
+ SetEvent(lpo->hEvent);
+ return CR_CONNECTED;
+
+ default:
+ break;
+ }
+
+failed:
+ error(_("ConnectNamedPipe failed for '%s' (%lu)"),
+ server_thread_data->server_data->buf_path.buf,
+ GetLastError());
+ return CR_CONNECT_ERROR;
+}
+
+/*
+ * Use Windows Overlapped IO to wait for a connection or for our event
+ * to be signalled.
+ */
+static enum connect_result wait_for_connection(
+ struct ipc_server_thread_data *server_thread_data,
+ OVERLAPPED *lpo)
+{
+ enum connect_result r;
+ HANDLE waitHandles[2];
+ DWORD dwWaitResult;
+
+ r = queue_overlapped_connect(server_thread_data, lpo);
+ if (r != CR_CONNECT_PENDING)
+ return r;
+
+ waitHandles[0] = server_thread_data->server_data->hEventStopRequested;
+ waitHandles[1] = lpo->hEvent;
+
+ dwWaitResult = WaitForMultipleObjects(2, waitHandles, FALSE, INFINITE);
+ switch (dwWaitResult) {
+ case WAIT_OBJECT_0 + 0:
+ return CR_SHUTDOWN;
+
+ case WAIT_OBJECT_0 + 1:
+ ResetEvent(lpo->hEvent);
+ return CR_CONNECTED;
+
+ default:
+ return CR_WAIT_ERROR;
+ }
+}
+
+/*
+ * Forward declare our reply callback function so that any compiler
+ * errors are reported when we actually define the function (in addition
+ * to any errors reported when we try to pass this callback function as
+ * a parameter in a function call). The former are easier to understand.
+ */
+static ipc_server_reply_cb do_io_reply_callback;
+
+/*
+ * Relay application's response message to the client process.
+ * (We do not flush at this point because we allow the caller
+ * to chunk data to the client thru us.)
+ */
+static int do_io_reply_callback(struct ipc_server_reply_data *reply_data,
+ const char *response, size_t response_len)
+{
+ if (reply_data->magic != MAGIC_SERVER_REPLY_DATA)
+ BUG("reply_cb called with wrong instance data");
+
+ return write_packetized_from_buf_no_flush(response, response_len,
+ reply_data->fd);
+}
+
+/*
+ * Receive the request/command from the client and pass it to the
+ * registered request-callback. The request-callback will compose
+ * a response and call our reply-callback to send it to the client.
+ *
+ * Simple-IPC only contains one round trip, so we flush and close
+ * here after the response.
+ */
+static int do_io(struct ipc_server_thread_data *server_thread_data)
+{
+ struct strbuf buf = STRBUF_INIT;
+ struct ipc_server_reply_data reply_data;
+ int ret = 0;
+
+ reply_data.magic = MAGIC_SERVER_REPLY_DATA;
+ reply_data.server_thread_data = server_thread_data;
+
+ reply_data.fd = dup_fd_from_pipe(server_thread_data->hPipe);
+ if (reply_data.fd < 0)
+ return error(_("could not create fd from pipe for '%s'"),
+ server_thread_data->server_data->buf_path.buf);
+
+ ret = read_packetized_to_strbuf(
+ reply_data.fd, &buf,
+ PACKET_READ_GENTLE_ON_EOF | PACKET_READ_GENTLE_ON_READ_ERROR);
+ if (ret >= 0) {
+ ret = server_thread_data->server_data->application_cb(
+ server_thread_data->server_data->application_data,
+ buf.buf, do_io_reply_callback, &reply_data);
+
+ packet_flush_gently(reply_data.fd);
+
+ FlushFileBuffers((HANDLE)_get_osfhandle((reply_data.fd)));
+ }
+ else {
+ /*
+ * The client probably disconnected/shutdown before it
+ * could send a well-formed message. Ignore it.
+ */
+ }
+
+ strbuf_release(&buf);
+ close(reply_data.fd);
+
+ return ret;
+}
+
+/*
+ * Handle IPC request and response with this connected client. And reset
+ * the pipe to prepare for the next client.
+ */
+static int use_connection(struct ipc_server_thread_data *server_thread_data)
+{
+ int ret;
+
+ ret = do_io(server_thread_data);
+
+ FlushFileBuffers(server_thread_data->hPipe);
+ DisconnectNamedPipe(server_thread_data->hPipe);
+
+ return ret;
+}
+
+/*
+ * Thread proc for an IPC server worker thread. It handles a series of
+ * connections from clients. It cleans and reuses the hPipe between each
+ * client.
+ */
+static void *server_thread_proc(void *_server_thread_data)
+{
+ struct ipc_server_thread_data *server_thread_data = _server_thread_data;
+ HANDLE hEventConnected = INVALID_HANDLE_VALUE;
+ OVERLAPPED oConnect;
+ enum connect_result cr;
+ int ret;
+
+ assert(server_thread_data->hPipe != INVALID_HANDLE_VALUE);
+
+ trace2_thread_start("ipc-server");
+ trace2_data_string("ipc-server", NULL, "pipe",
+ server_thread_data->server_data->buf_path.buf);
+
+ hEventConnected = CreateEventW(NULL, TRUE, FALSE, NULL);
+
+ memset(&oConnect, 0, sizeof(oConnect));
+ oConnect.hEvent = hEventConnected;
+
+ for (;;) {
+ cr = wait_for_connection(server_thread_data, &oConnect);
+
+ switch (cr) {
+ case CR_SHUTDOWN:
+ goto finished;
+
+ case CR_CONNECTED:
+ ret = use_connection(server_thread_data);
+ if (ret == SIMPLE_IPC_QUIT) {
+ ipc_server_stop_async(
+ server_thread_data->server_data);
+ goto finished;
+ }
+ if (ret > 0) {
+ /*
+ * Ignore (transient) IO errors with this
+ * client and reset for the next client.
+ */
+ }
+ break;
+
+ case CR_CONNECT_PENDING:
+ /* By construction, this should not happen. */
+ BUG("ipc-server[%s]: unexpeced CR_CONNECT_PENDING",
+ server_thread_data->server_data->buf_path.buf);
+
+ case CR_CONNECT_ERROR:
+ case CR_WAIT_ERROR:
+ /*
+ * Ignore these theoretical errors.
+ */
+ DisconnectNamedPipe(server_thread_data->hPipe);
+ break;
+
+ default:
+ BUG("unandled case after wait_for_connection");
+ }
+ }
+
+finished:
+ CloseHandle(server_thread_data->hPipe);
+ CloseHandle(hEventConnected);
+
+ trace2_thread_exit();
+ return NULL;
+}
+
+static HANDLE create_new_pipe(wchar_t *wpath, int is_first)
+{
+ HANDLE hPipe;
+ DWORD dwOpenMode, dwPipeMode;
+ LPSECURITY_ATTRIBUTES lpsa = NULL;
+
+ dwOpenMode = PIPE_ACCESS_INBOUND | PIPE_ACCESS_OUTBOUND |
+ FILE_FLAG_OVERLAPPED;
+
+ dwPipeMode = PIPE_TYPE_MESSAGE | PIPE_READMODE_BYTE | PIPE_WAIT |
+ PIPE_REJECT_REMOTE_CLIENTS;
+
+ if (is_first) {
+ dwOpenMode |= FILE_FLAG_FIRST_PIPE_INSTANCE;
+
+ /*
+ * On Windows, the first server pipe instance gets to
+ * set the ACL / Security Attributes on the named
+ * pipe; subsequent instances inherit and cannot
+ * change them.
+ *
+ * TODO Should we allow the application layer to
+ * specify security attributes, such as `LocalService`
+ * or `LocalSystem`, when we create the named pipe?
+ * This question is probably not important when the
+ * daemon is started by a foreground user process and
+ * only needs to talk to the current user, but may be
+ * if the daemon is run via the Control Panel as a
+ * System Service.
+ */
+ }
+
+ hPipe = CreateNamedPipeW(wpath, dwOpenMode, dwPipeMode,
+ PIPE_UNLIMITED_INSTANCES, 1024, 1024, 0, lpsa);
+
+ return hPipe;
+}
+
+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)
+{
+ struct ipc_server_data *server_data;
+ wchar_t wpath[MAX_PATH];
+ HANDLE hPipeFirst = INVALID_HANDLE_VALUE;
+ int k;
+ int ret = 0;
+ int nr_threads = opts->nr_threads;
+
+ *returned_server_data = NULL;
+
+ ret = initialize_pipe_name(path, wpath, ARRAY_SIZE(wpath));
+ if (ret < 0) {
+ errno = EINVAL;
+ return -1;
+ }
+
+ hPipeFirst = create_new_pipe(wpath, 1);
+ if (hPipeFirst == INVALID_HANDLE_VALUE) {
+ errno = EADDRINUSE;
+ return -2;
+ }
+
+ server_data = xcalloc(1, sizeof(*server_data));
+ server_data->magic = MAGIC_SERVER_DATA;
+ server_data->application_cb = application_cb;
+ server_data->application_data = application_data;
+ server_data->hEventStopRequested = CreateEvent(NULL, TRUE, FALSE, NULL);
+ strbuf_init(&server_data->buf_path, 0);
+ strbuf_addstr(&server_data->buf_path, path);
+ wcscpy(server_data->wpath, wpath);
+
+ if (nr_threads < 1)
+ nr_threads = 1;
+
+ for (k = 0; k < nr_threads; k++) {
+ struct ipc_server_thread_data *std;
+
+ std = xcalloc(1, sizeof(*std));
+ std->magic = MAGIC_SERVER_THREAD_DATA;
+ std->server_data = server_data;
+ std->hPipe = INVALID_HANDLE_VALUE;
+
+ std->hPipe = (k == 0)
+ ? hPipeFirst
+ : create_new_pipe(server_data->wpath, 0);
+
+ if (std->hPipe == INVALID_HANDLE_VALUE) {
+ /*
+ * If we've reached a pipe instance limit for
+ * this path, just use fewer threads.
+ */
+ free(std);
+ break;
+ }
+
+ if (pthread_create(&std->pthread_id, NULL,
+ server_thread_proc, std)) {
+ /*
+ * Likewise, if we're out of threads, just use
+ * fewer threads than requested.
+ *
+ * However, we just give up if we can't even get
+ * one thread. This should not happen.
+ */
+ if (k == 0)
+ die(_("could not start thread[0] for '%s'"),
+ path);
+
+ CloseHandle(std->hPipe);
+ free(std);
+ break;
+ }
+
+ std->next_thread = server_data->thread_list;
+ server_data->thread_list = std;
+ }
+
+ *returned_server_data = server_data;
+ return 0;
+}
+
+int ipc_server_stop_async(struct ipc_server_data *server_data)
+{
+ if (!server_data)
+ return 0;
+
+ /*
+ * Gently tell all of the ipc_server threads to shutdown.
+ * This will be seen the next time they are idle (and waiting
+ * for a connection).
+ *
+ * We DO NOT attempt to force them to drop an active connection.
+ */
+ SetEvent(server_data->hEventStopRequested);
+ return 0;
+}
+
+int ipc_server_await(struct ipc_server_data *server_data)
+{
+ DWORD dwWaitResult;
+
+ if (!server_data)
+ return 0;
+
+ dwWaitResult = WaitForSingleObject(server_data->hEventStopRequested, INFINITE);
+ if (dwWaitResult != WAIT_OBJECT_0)
+ return error(_("wait for hEvent failed for '%s'"),
+ server_data->buf_path.buf);
+
+ while (server_data->thread_list) {
+ struct ipc_server_thread_data *std = server_data->thread_list;
+
+ pthread_join(std->pthread_id, NULL);
+
+ server_data->thread_list = std->next_thread;
+ free(std);
+ }
+
+ server_data->is_stopped = 1;
+
+ return 0;
+}
+
+void ipc_server_free(struct ipc_server_data *server_data)
+{
+ if (!server_data)
+ return;
+
+ if (!server_data->is_stopped)
+ BUG("cannot free ipc-server while running for '%s'",
+ server_data->buf_path.buf);
+
+ strbuf_release(&server_data->buf_path);
+
+ if (server_data->hEventStopRequested != INVALID_HANDLE_VALUE)
+ CloseHandle(server_data->hEventStopRequested);
+
+ while (server_data->thread_list) {
+ struct ipc_server_thread_data *std = server_data->thread_list;
+
+ server_data->thread_list = std->next_thread;
+ free(std);
+ }
+
+ free(server_data);
+}
--- /dev/null
+#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 */
projects / thirdparty / git.git / commitdiff
