diff options
| -rw-r--r-- | Documentation/technical/api-simple-ipc.txt | 105 | ||||
| -rw-r--r-- | Makefile | 9 | ||||
| -rw-r--r-- | builtin/credential-cache--daemon.c | 3 | ||||
| -rw-r--r-- | builtin/credential-cache.c | 2 | ||||
| -rw-r--r-- | compat/simple-ipc/ipc-shared.c | 28 | ||||
| -rw-r--r-- | compat/simple-ipc/ipc-unix-socket.c | 999 | ||||
| -rw-r--r-- | compat/simple-ipc/ipc-win32.c | 751 | ||||
| -rw-r--r-- | config.mak.uname | 2 | ||||
| -rw-r--r-- | contrib/buildsystems/CMakeLists.txt | 8 | ||||
| -rw-r--r-- | convert.c | 11 | ||||
| -rw-r--r-- | pkt-line.c | 59 | ||||
| -rw-r--r-- | pkt-line.h | 17 | ||||
| -rw-r--r-- | simple-ipc.h | 239 | ||||
| -rw-r--r-- | t/helper/test-simple-ipc.c | 787 | ||||
| -rw-r--r-- | t/helper/test-tool.c | 1 | ||||
| -rw-r--r-- | t/helper/test-tool.h | 1 | ||||
| -rwxr-xr-x | t/t0052-simple-ipc.sh | 122 | ||||
| -rw-r--r-- | unix-socket.c | 53 | ||||
| -rw-r--r-- | unix-socket.h | 12 | ||||
| -rw-r--r-- | unix-stream-server.c | 125 | ||||
| -rw-r--r-- | unix-stream-server.h | 33 |
21 files changed, 3315 insertions, 52 deletions
diff --git a/Documentation/technical/api-simple-ipc.txt b/Documentation/technical/api-simple-ipc.txt new file mode 100644 index 0000000000..d79ad323e6 --- /dev/null +++ b/Documentation/technical/api-simple-ipc.txt @@ -0,0 +1,105 @@ +Simple-IPC API +============== + +The Simple-IPC API is a collection of `ipc_` prefixed library routines +and a basic communication protocol that allow an IPC-client process to +send an application-specific IPC-request message to an IPC-server +process and receive an application-specific IPC-response message. + +Communication occurs over a named pipe on Windows and a Unix domain +socket on other platforms. IPC-clients and IPC-servers rendezvous at +a previously agreed-to application-specific pathname (which is outside +the scope of this design) that is local to the computer system. + +The IPC-server routines within the server application process create a +thread pool to listen for connections and receive request messages +from multiple concurrent IPC-clients. When received, these messages +are dispatched up to the server application callbacks for handling. +IPC-server routines then incrementally relay responses back to the +IPC-client. + +The IPC-client routines within a client application process connect +to the IPC-server and send a request message and wait for a response. +When received, the response is returned back the caller. + +For example, the `fsmonitor--daemon` feature will be built as a server +application on top of the IPC-server library routines. It will have +threads watching for file system events and a thread pool waiting for +client connections. Clients, such as `git status` will request a list +of file system events since a point in time and the server will +respond with a list of changed files and directories. The formats of +the request and response are application-specific; the IPC-client and +IPC-server routines treat them as opaque byte streams. + + +Comparison with sub-process model +--------------------------------- + +The Simple-IPC mechanism differs from the existing `sub-process.c` +model (Documentation/technical/long-running-process-protocol.txt) and +used by applications like Git-LFS. In the LFS-style sub-process model +the helper is started by the foreground process, communication happens +via a pair of file descriptors bound to the stdin/stdout of the +sub-process, the sub-process only serves the current foreground +process, and the sub-process exits when the foreground process +terminates. + +In the Simple-IPC model the server is a very long-running service. It +can service many clients at the same time and has a private socket or +named pipe connection to each active client. It might be started +(on-demand) by the current client process or it might have been +started by a previous client or by the OS at boot time. The server +process is not associated with a terminal and it persists after +clients terminate. Clients do not have access to the stdin/stdout of +the server process and therefore must communicate over sockets or +named pipes. + + +Server startup and shutdown +--------------------------- + +How an application server based upon IPC-server is started is also +outside the scope of the Simple-IPC design and is a property of the +application using it. For example, the server might be started or +restarted during routine maintenance operations, or it might be +started as a system service during the system boot-up sequence, or it +might be started on-demand by a foreground Git command when needed. + +Similarly, server shutdown is a property of the application using +the simple-ipc routines. For example, the server might decide to +shutdown when idle or only upon explicit request. + + +Simple-IPC protocol +------------------- + +The Simple-IPC protocol consists of a single request message from the +client and an optional response message from the server. Both the +client and server messages are unlimited in length and are terminated +with a flush packet. + +The pkt-line routines (Documentation/technical/protocol-common.txt) +are used to simplify buffer management during message generation, +transmission, and reception. A flush packet is used to mark the end +of the message. This allows the sender to incrementally generate and +transmit the message. It allows the receiver to incrementally receive +the message in chunks and to know when they have received the entire +message. + +The actual byte format of the client request and server response +messages are application specific. The IPC layer transmits and +receives them as opaque byte buffers without any concern for the +content within. It is the job of the calling application layer to +understand the contents of the request and response messages. + + +Summary +------- + +Conceptually, the Simple-IPC protocol is similar to an HTTP REST +request. Clients connect, make an application-specific and +stateless request, receive an application-specific +response, and disconnect. It is a one round trip facility for +querying the server. The Simple-IPC routines hide the socket, +named pipe, and thread pool details and allow the application +layer to focus on the application at hand. @@ -744,6 +744,7 @@ TEST_BUILTINS_OBJS += test-serve-v2.o TEST_BUILTINS_OBJS += test-sha1.o TEST_BUILTINS_OBJS += test-sha256.o TEST_BUILTINS_OBJS += test-sigchain.o +TEST_BUILTINS_OBJS += test-simple-ipc.o TEST_BUILTINS_OBJS += test-strcmp-offset.o TEST_BUILTINS_OBJS += test-string-list.o TEST_BUILTINS_OBJS += test-submodule-config.o @@ -1679,6 +1680,14 @@ ifdef NO_UNIX_SOCKETS BASIC_CFLAGS += -DNO_UNIX_SOCKETS else LIB_OBJS += unix-socket.o + LIB_OBJS += unix-stream-server.o + LIB_OBJS += compat/simple-ipc/ipc-shared.o + LIB_OBJS += compat/simple-ipc/ipc-unix-socket.o +endif + +ifdef USE_WIN32_IPC + LIB_OBJS += compat/simple-ipc/ipc-shared.o + LIB_OBJS += compat/simple-ipc/ipc-win32.o endif ifdef NO_ICONV diff --git a/builtin/credential-cache--daemon.c b/builtin/credential-cache--daemon.c index c61f123a3b..4c6c89ab0d 100644 --- a/builtin/credential-cache--daemon.c +++ b/builtin/credential-cache--daemon.c @@ -203,9 +203,10 @@ static int serve_cache_loop(int fd) static void serve_cache(const char *socket_path, int debug) { + struct unix_stream_listen_opts opts = UNIX_STREAM_LISTEN_OPTS_INIT; int fd; - fd = unix_stream_listen(socket_path); + fd = unix_stream_listen(socket_path, &opts); if (fd < 0) die_errno("unable to bind to '%s'", socket_path); diff --git a/builtin/credential-cache.c b/builtin/credential-cache.c index 9b3f709905..76a6ba3722 100644 --- a/builtin/credential-cache.c +++ b/builtin/credential-cache.c @@ -14,7 +14,7 @@ static int send_request(const char *socket, const struct strbuf *out) { int got_data = 0; - int fd = unix_stream_connect(socket); + int fd = unix_stream_connect(socket, 0); if (fd < 0) return -1; diff --git a/compat/simple-ipc/ipc-shared.c b/compat/simple-ipc/ipc-shared.c new file mode 100644 index 0000000000..1edec81595 --- /dev/null +++ b/compat/simple-ipc/ipc-shared.c @@ -0,0 +1,28 @@ +#include "cache.h" +#include "simple-ipc.h" +#include "strbuf.h" +#include "pkt-line.h" +#include "thread-utils.h" + +#ifdef SUPPORTS_SIMPLE_IPC + +int ipc_server_run(const char *path, const struct ipc_server_opts *opts, + ipc_server_application_cb *application_cb, + void *application_data) +{ + struct ipc_server_data *server_data = NULL; + int ret; + + ret = ipc_server_run_async(&server_data, path, opts, + application_cb, application_data); + if (ret) + return ret; + + ret = ipc_server_await(server_data); + + ipc_server_free(server_data); + + return ret; +} + +#endif /* SUPPORTS_SIMPLE_IPC */ diff --git a/compat/simple-ipc/ipc-unix-socket.c b/compat/simple-ipc/ipc-unix-socket.c new file mode 100644 index 0000000000..38689b278d --- /dev/null +++ b/compat/simple-ipc/ipc-unix-socket.c @@ -0,0 +1,999 @@ +#include "cache.h" +#include "simple-ipc.h" +#include "strbuf.h" +#include "pkt-line.h" +#include "thread-utils.h" +#include "unix-socket.h" +#include "unix-stream-server.h" + +#ifdef NO_UNIX_SOCKETS +#error compat/simple-ipc/ipc-unix-socket.c requires Unix sockets +#endif + +enum ipc_active_state ipc_get_active_state(const char *path) +{ + enum ipc_active_state state = IPC_STATE__OTHER_ERROR; + struct ipc_client_connect_options options + = IPC_CLIENT_CONNECT_OPTIONS_INIT; + struct stat st; + struct ipc_client_connection *connection_test = NULL; + + options.wait_if_busy = 0; + options.wait_if_not_found = 0; + + if (lstat(path, &st) == -1) { + switch (errno) { + case ENOENT: + case ENOTDIR: + return IPC_STATE__NOT_LISTENING; + default: + return IPC_STATE__INVALID_PATH; + } + } + + /* also complain if a plain file is in the way */ + if ((st.st_mode & S_IFMT) != S_IFSOCK) + return IPC_STATE__INVALID_PATH; + + /* + * Just because the filesystem has a S_IFSOCK type inode + * at `path`, doesn't mean it that there is a server listening. + * Ping it to be sure. + */ + state = ipc_client_try_connect(path, &options, &connection_test); + ipc_client_close_connection(connection_test); + + return state; +} + +/* + * Retry frequency when trying to connect to a server. + * + * This value should be short enough that we don't seriously delay our + * caller, but not fast enough that our spinning puts pressure on the + * system. + */ +#define WAIT_STEP_MS (50) + +/* + * Try to connect to the server. If the server is just starting up or + * is very busy, we may not get a connection the first time. + */ +static enum ipc_active_state connect_to_server( + const char *path, + int timeout_ms, + const struct ipc_client_connect_options *options, + int *pfd) +{ + int k; + + *pfd = -1; + + for (k = 0; k < timeout_ms; k += WAIT_STEP_MS) { + int fd = unix_stream_connect(path, options->uds_disallow_chdir); + + if (fd != -1) { + *pfd = fd; + return IPC_STATE__LISTENING; + } + + if (errno == ENOENT) { + if (!options->wait_if_not_found) + return IPC_STATE__PATH_NOT_FOUND; + + goto sleep_and_try_again; + } + + if (errno == ETIMEDOUT) { + if (!options->wait_if_busy) + return IPC_STATE__NOT_LISTENING; + + goto sleep_and_try_again; + } + + if (errno == ECONNREFUSED) { + if (!options->wait_if_busy) + return IPC_STATE__NOT_LISTENING; + + goto sleep_and_try_again; + } + + return IPC_STATE__OTHER_ERROR; + + sleep_and_try_again: + sleep_millisec(WAIT_STEP_MS); + } + + return IPC_STATE__NOT_LISTENING; +} + +/* + * The total amount of time that we are willing to wait when trying to + * connect to a server. + * + * When the server is first started, it might take a little while for + * it to become ready to service requests. Likewise, the server may + * be very (temporarily) busy and not respond to our connections. + * + * We should gracefully and silently handle those conditions and try + * again for a reasonable time period. + * + * The value chosen here should be long enough for the server + * to reliably heal from the above conditions. + */ +#define MY_CONNECTION_TIMEOUT_MS (1000) + +enum ipc_active_state ipc_client_try_connect( + const char *path, + const struct ipc_client_connect_options *options, + struct ipc_client_connection **p_connection) +{ + 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); + + state = connect_to_server(path, MY_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; + } + + 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 *answer) +{ + 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, answer); + + ipc_client_close_connection(connection); + + return ret; +} + +static int set_socket_blocking_flag(int fd, int make_nonblocking) +{ + int flags; + + flags = fcntl(fd, F_GETFL, NULL); + + if (flags < 0) + return -1; + + if (make_nonblocking) + flags |= O_NONBLOCK; + else + flags &= ~O_NONBLOCK; + + return fcntl(fd, F_SETFL, flags); +} + +/* + * 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_WORKER_THREAD_DATA, + MAGIC_ACCEPT_THREAD_DATA, + MAGIC_SERVER_DATA, +}; + +struct ipc_server_reply_data { + enum magic magic; + int fd; + struct ipc_worker_thread_data *worker_thread_data; +}; + +struct ipc_worker_thread_data { + enum magic magic; + struct ipc_worker_thread_data *next_thread; + struct ipc_server_data *server_data; + pthread_t pthread_id; +}; + +struct ipc_accept_thread_data { + enum magic magic; + struct ipc_server_data *server_data; + + struct unix_ss_socket *server_socket; + + int fd_send_shutdown; + int fd_wait_shutdown; + pthread_t pthread_id; +}; + +/* + * With unix-sockets, the conceptual "ipc-server" is implemented as a single + * controller "accept-thread" thread and a pool of "worker-thread" threads. + * The former does the usual `accept()` loop and dispatches connections + * to an idle worker thread. The worker threads wait in an idle loop for + * a new connection, communicate with the client and relay data to/from + * the `application_cb` and then wait for another connection from the + * server thread. This avoids the overhead of constantly creating and + * destroying threads. + */ +struct ipc_server_data { + enum magic magic; + ipc_server_application_cb *application_cb; + void *application_data; + struct strbuf buf_path; + + struct ipc_accept_thread_data *accept_thread; + struct ipc_worker_thread_data *worker_thread_list; + + pthread_mutex_t work_available_mutex; + pthread_cond_t work_available_cond; + + /* + * Accepted but not yet processed client connections are kept + * in a circular buffer FIFO. The queue is empty when the + * positions are equal. + */ + int *fifo_fds; + int queue_size; + int back_pos; + int front_pos; + + int shutdown_requested; + int is_stopped; +}; + +/* + * Remove and return the oldest queued connection. + * + * Returns -1 if empty. + */ +static int fifo_dequeue(struct ipc_server_data *server_data) +{ + /* ASSERT holding mutex */ + + int fd; + + if (server_data->back_pos == server_data->front_pos) + return -1; + + fd = server_data->fifo_fds[server_data->front_pos]; + server_data->fifo_fds[server_data->front_pos] = -1; + + server_data->front_pos++; + if (server_data->front_pos == server_data->queue_size) + server_data->front_pos = 0; + + return fd; +} + +/* + * Push a new fd onto the back of the queue. + * + * Drop it and return -1 if queue is already full. + */ +static int fifo_enqueue(struct ipc_server_data *server_data, int fd) +{ + /* ASSERT holding mutex */ + + int next_back_pos; + + next_back_pos = server_data->back_pos + 1; + if (next_back_pos == server_data->queue_size) + next_back_pos = 0; + + if (next_back_pos == server_data->front_pos) { + /* Queue is full. Just drop it. */ + close(fd); + return -1; + } + + server_data->fifo_fds[server_data->back_pos] = fd; + server_data->back_pos = next_back_pos; + + return fd; +} + +/* + * Wait for a connection to be queued to the FIFO and return it. + * + * Returns -1 if someone has already requested a shutdown. + */ +static int worker_thread__wait_for_connection( + struct ipc_worker_thread_data *worker_thread_data) +{ + /* ASSERT NOT holding mutex */ + + struct ipc_server_data *server_data = worker_thread_data->server_data; + int fd = -1; + + pthread_mutex_lock(&server_data->work_available_mutex); + for (;;) { + if (server_data->shutdown_requested) + break; + + fd = fifo_dequeue(server_data); + if (fd >= 0) + break; + + pthread_cond_wait(&server_data->work_available_cond, + &server_data->work_available_mutex); + } + pthread_mutex_unlock(&server_data->work_available_mutex); + + return fd; +} + +/* + * 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); +} + +/* A randomly chosen value. */ +#define MY_WAIT_POLL_TIMEOUT_MS (10) + +/* + * If the client hangs up without sending any data on the wire, just + * quietly close the socket and ignore this client. + * + * This worker thread is committed to reading the IPC request data + * from the client at the other end of this fd. Wait here for the + * client to actually put something on the wire -- because if the + * client just does a ping (connect and hangup without sending any + * data), our use of the pkt-line read routines will spew an error + * message. + * + * Return -1 if the client hung up. + * Return 0 if data (possibly incomplete) is ready. + */ +static int worker_thread__wait_for_io_start( + struct ipc_worker_thread_data *worker_thread_data, + int fd) +{ + struct ipc_server_data *server_data = worker_thread_data->server_data; + struct pollfd pollfd[1]; + int result; + + for (;;) { + pollfd[0].fd = fd; + pollfd[0].events = POLLIN; + + result = poll(pollfd, 1, MY_WAIT_POLL_TIMEOUT_MS); + if (result < 0) { + if (errno == EINTR) + continue; + goto cleanup; + } + + if (result == 0) { + /* a timeout */ + + int in_shutdown; + + pthread_mutex_lock(&server_data->work_available_mutex); + in_shutdown = server_data->shutdown_requested; + pthread_mutex_unlock(&server_data->work_available_mutex); + + /* + * If a shutdown is already in progress and this + * client has not started talking yet, just drop it. + */ + if (in_shutdown) + goto cleanup; + continue; + } + + if (pollfd[0].revents & POLLHUP) + goto cleanup; + + if (pollfd[0].revents & POLLIN) + return 0; + + goto cleanup; + } + +cleanup: + close(fd); + return -1; +} + +/* + * 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. + */ +static int worker_thread__do_io( + struct ipc_worker_thread_data *worker_thread_data, + int fd) +{ + /* ASSERT NOT holding lock */ + + struct strbuf buf = STRBUF_INIT; + struct ipc_server_reply_data reply_data; + int ret = 0; + + reply_data.magic = MAGIC_SERVER_REPLY_DATA; + reply_data.worker_thread_data = worker_thread_data; + + reply_data.fd = fd; + + ret = read_packetized_to_strbuf( + reply_data.fd, &buf, + PACKET_READ_GENTLE_ON_EOF | PACKET_READ_GENTLE_ON_READ_ERROR); + if (ret >= 0) { + ret = worker_thread_data->server_data->application_cb( + worker_thread_data->server_data->application_data, + buf.buf, do_io_reply_callback, &reply_data); + + packet_flush_gently(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; +} + +/* + * Block SIGPIPE on the current thread (so that we get EPIPE from + * write() rather than an actual signal). + * + * Note that using sigchain_push() and _pop() to control SIGPIPE + * around our IO calls is not thread safe: + * [] It uses a global stack of handler frames. + * [] It uses ALLOC_GROW() to resize it. + * [] Finally, according to the `signal(2)` man-page: + * "The effects of `signal()` in a multithreaded process are unspecified." + */ +static void thread_block_sigpipe(sigset_t *old_set) +{ + sigset_t new_set; + + sigemptyset(&new_set); + sigaddset(&new_set, SIGPIPE); + + sigemptyset(old_set); + pthread_sigmask(SIG_BLOCK, &new_set, old_set); +} + +/* + * Thread proc for an IPC worker thread. It handles a series of + * connections from clients. It pulls the next fd from the queue + * processes it, and then waits for the next client. + * + * Block SIGPIPE in this worker thread for the life of the thread. + * This avoids stray (and sometimes delayed) SIGPIPE signals caused + * by client errors and/or when we are under extremely heavy IO load. + * + * This means that the application callback will have SIGPIPE blocked. + * The callback should not change it. + */ +static void *worker_thread_proc(void *_worker_thread_data) +{ + struct ipc_worker_thread_data *worker_thread_data = _worker_thread_data; + struct ipc_server_data *server_data = worker_thread_data->server_data; + sigset_t old_set; + int fd, io; + int ret; + + trace2_thread_start("ipc-worker"); + + thread_block_sigpipe(&old_set); + + for (;;) { + fd = worker_thread__wait_for_connection(worker_thread_data); + if (fd == -1) + break; /* in shutdown */ + + io = worker_thread__wait_for_io_start(worker_thread_data, fd); + if (io == -1) + continue; /* client hung up without sending anything */ + + ret = worker_thread__do_io(worker_thread_data, fd); + + if (ret == SIMPLE_IPC_QUIT) { + trace2_data_string("ipc-worker", NULL, "queue_stop_async", + "application_quit"); + /* + * The application layer is telling the ipc-server + * layer to shutdown. + * + * We DO NOT have a response to send to the client. + * + * Queue an async stop (to stop the other threads) and + * allow this worker thread to exit now (no sense waiting + * for the thread-pool shutdown signal). + * + * Other non-idle worker threads are allowed to finish + * responding to their current clients. + */ + ipc_server_stop_async(server_data); + break; + } + } + + trace2_thread_exit(); + return NULL; +} + +/* A randomly chosen value. */ +#define MY_ACCEPT_POLL_TIMEOUT_MS (60 * 1000) + +/* + * Accept a new client connection on our socket. This uses non-blocking + * IO so that we can also wait for shutdown requests on our socket-pair + * without actually spinning on a fast timeout. + */ +static int accept_thread__wait_for_connection( + struct ipc_accept_thread_data *accept_thread_data) +{ + struct pollfd pollfd[2]; + int result; + + for (;;) { + pollfd[0].fd = accept_thread_data->fd_wait_shutdown; + pollfd[0].events = POLLIN; + + pollfd[1].fd = accept_thread_data->server_socket->fd_socket; + pollfd[1].events = POLLIN; + + result = poll(pollfd, 2, MY_ACCEPT_POLL_TIMEOUT_MS); + if (result < 0) { + if (errno == EINTR) + continue; + return result; + } + + if (result == 0) { + /* a timeout */ + + /* + * If someone deletes or force-creates a new unix + * domain socket at our path, all future clients + * will be routed elsewhere and we silently starve. + * If that happens, just queue a shutdown. + */ + if (unix_ss_was_stolen( + accept_thread_data->server_socket)) { + trace2_data_string("ipc-accept", NULL, + "queue_stop_async", + "socket_stolen"); + ipc_server_stop_async( + accept_thread_data->server_data); + } + continue; + } + + if (pollfd[0].revents & POLLIN) { + /* shutdown message queued to socketpair */ + return -1; + } + + if (pollfd[1].revents & POLLIN) { + /* a connection is available on server_socket */ + + int client_fd = + accept(accept_thread_data->server_socket->fd_socket, + NULL, NULL); + if (client_fd >= 0) + return client_fd; + + /* + * An error here is unlikely -- it probably + * indicates that the connecting process has + * already dropped the connection. + */ + continue; + } + + BUG("unandled poll result errno=%d r[0]=%d r[1]=%d", + errno, pollfd[0].revents, pollfd[1].revents); + } +} + +/* + * Thread proc for the IPC server "accept thread". This waits for + * an incoming socket connection, appends it to the queue of available + * connections, and notifies a worker thread to process it. + * + * Block SIGPIPE in this thread for the life of the thread. This + * avoids any stray SIGPIPE signals when closing pipe fds under + * extremely heavy loads (such as when the fifo queue is full and we + * drop incomming connections). + */ +static void *accept_thread_proc(void *_accept_thread_data) +{ + struct ipc_accept_thread_data *accept_thread_data = _accept_thread_data; + struct ipc_server_data *server_data = accept_thread_data->server_data; + sigset_t old_set; + + trace2_thread_start("ipc-accept"); + + thread_block_sigpipe(&old_set); + + for (;;) { + int client_fd = accept_thread__wait_for_connection( + accept_thread_data); + + pthread_mutex_lock(&server_data->work_available_mutex); + if (server_data->shutdown_requested) { + pthread_mutex_unlock(&server_data->work_available_mutex); + if (client_fd >= 0) + close(client_fd); + break; + } + + if (client_fd < 0) { + /* ignore transient accept() errors */ + } + else { + fifo_enqueue(server_data, client_fd); + pthread_cond_broadcast(&server_data->work_available_cond); + } + pthread_mutex_unlock(&server_data->work_available_mutex); + } + + trace2_thread_exit(); + return NULL; +} + +/* + * We can't predict the connection arrival rate relative to the worker + * processing rate, therefore we allow the "accept-thread" to queue up + * a generous number of connections, since we'd rather have the client + * not unnecessarily timeout if we can avoid it. (The assumption is + * that this will be used for FSMonitor and a few second wait on a + * connection is better than having the client timeout and do the full + * computation itself.) + * + * The FIFO queue size is set to a multiple of the worker pool size. + * This value chosen at random. + */ +#define FIFO_SCALE (100) + +/* + * The backlog value for `listen(2)`. This doesn't need to huge, + * rather just large enough for our "accept-thread" to wake up and + * queue incoming connections onto the FIFO without the kernel + * dropping any. + * + * This value chosen at random. + */ +#define LISTEN_BACKLOG (50) + +static int create_listener_socket( + const char *path, + const struct ipc_server_opts *ipc_opts, + struct unix_ss_socket **new_server_socket) +{ + struct unix_ss_socket *server_socket = NULL; + struct unix_stream_listen_opts uslg_opts = UNIX_STREAM_LISTEN_OPTS_INIT; + int ret; + + uslg_opts.listen_backlog_size = LISTEN_BACKLOG; + uslg_opts.disallow_chdir = ipc_opts->uds_disallow_chdir; + + ret = unix_ss_create(path, &uslg_opts, -1, &server_socket); + if (ret) + return ret; + + if (set_socket_blocking_flag(server_socket->fd_socket, 1)) { + int saved_errno = errno; + unix_ss_free(server_socket); + errno = saved_errno; + return -1; + } + + *new_server_socket = server_socket; + + trace2_data_string("ipc-server", NULL, "listen-with-lock", path); + return 0; +} + +static int setup_listener_socket( + const char *path, + const struct ipc_server_opts *ipc_opts, + struct unix_ss_socket **new_server_socket) +{ + int ret, saved_errno; + + trace2_region_enter("ipc-server", "create-listener_socket", NULL); + + ret = create_listener_socket(path, ipc_opts, new_server_socket); + + saved_errno = errno; + trace2_region_leave("ipc-server", "create-listener_socket", NULL); + errno = saved_errno; + + return ret; +} + +/* + * Start IPC server in a pool of background threads. + */ +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 unix_ss_socket *server_socket = NULL; + struct ipc_server_data *server_data; + int sv[2]; + int k; + int ret; + int nr_threads = opts->nr_threads; + + *returned_server_data = NULL; + + /* + * Create a socketpair and set sv[1] to non-blocking. This + * will used to send a shutdown message to the accept-thread + * and allows the accept-thread to wait on EITHER a client + * connection or a shutdown request without spinning. + */ + if (socketpair(AF_UNIX, SOCK_STREAM, 0, sv) < 0) + return -1; + + if (set_socket_blocking_flag(sv[1], 1)) { + int saved_errno = errno; + close(sv[0]); + close(sv[1]); + errno = saved_errno; + return -1; + } + + ret = setup_listener_socket(path, opts, &server_socket); + if (ret) { + int saved_errno = errno; + close(sv[0]); + close(sv[1]); + errno = saved_errno; + return ret; + } + + 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; + strbuf_init(&server_data->buf_path, 0); + strbuf_addstr(&server_data->buf_path, path); + + if (nr_threads < 1) + nr_threads = 1; + + pthread_mutex_init(&server_data->work_available_mutex, NULL); + pthread_cond_init(&server_data->work_available_cond, NULL); + + server_data->queue_size = nr_threads * FIFO_SCALE; + CALLOC_ARRAY(server_data->fifo_fds, server_data->queue_size); + + server_data->accept_thread = + xcalloc(1, sizeof(*server_data->accept_thread)); + server_data->accept_thread->magic = MAGIC_ACCEPT_THREAD_DATA; + server_data->accept_thread->server_data = server_data; + server_data->accept_thread->server_socket = server_socket; + server_data->accept_thread->fd_send_shutdown = sv[0]; + server_data->accept_thread->fd_wait_shutdown = sv[1]; + + if (pthread_create(&server_data->accept_thread->pthread_id, NULL, + accept_thread_proc, server_data->accept_thread)) + die_errno(_("could not start accept_thread '%s'"), path); + + for (k = 0; k < nr_threads; k++) { + struct ipc_worker_thread_data *wtd; + + wtd = xcalloc(1, sizeof(*wtd)); + wtd->magic = MAGIC_WORKER_THREAD_DATA; + wtd->server_data = server_data; + + if (pthread_create(&wtd->pthread_id, NULL, worker_thread_proc, + wtd)) { + if (k == 0) + die(_("could not start worker[0] for '%s'"), + path); + /* + * Limp along with the thread pool that we have. + */ + break; + } + + wtd->next_thread = server_data->worker_thread_list; + server_data->worker_thread_list = wtd; + } + + *returned_server_data = server_data; + return 0; +} + +/* + * Gently tell the IPC server treads to shutdown. + * Can be run on any thread. + */ +int ipc_server_stop_async(struct ipc_server_data *server_data) +{ + /* ASSERT NOT holding mutex */ + + int fd; + + if (!server_data) + return 0; + + trace2_region_enter("ipc-server", "server-stop-async", NULL); + + pthread_mutex_lock(&server_data->work_available_mutex); + + server_data->shutdown_requested = 1; + + /* + * Write a byte to the shutdown socket pair to wake up the + * accept-thread. + */ + if (write(server_data->accept_thread->fd_send_shutdown, "Q", 1) < 0) + error_errno("could not write to fd_send_shutdown"); + + /* + * Drain the queue of existing connections. + */ + while ((fd = fifo_dequeue(server_data)) != -1) + close(fd); + + /* + * Gently tell worker threads to stop processing new connections + * and exit. (This does not abort in-process conversations.) + */ + pthread_cond_broadcast(&server_data->work_available_cond); + + pthread_mutex_unlock(&server_data->work_available_mutex); + + trace2_region_leave("ipc-server", "server-stop-async", NULL); + + return 0; +} + +/* + * Wait for all IPC server threads to stop. + */ +int ipc_server_await(struct ipc_server_data *server_data) +{ + pthread_join(server_data->accept_thread->pthread_id, NULL); + + if (!server_data->shutdown_requested) + BUG("ipc-server: accept-thread stopped for '%s'", + server_data->buf_path.buf); + + while (server_data->worker_thread_list) { + struct ipc_worker_thread_data *wtd = + server_data->worker_thread_list; + + pthread_join(wtd->pthread_id, NULL); + + server_data->worker_thread_list = wtd->next_thread; + free(wtd); + } + + server_data->is_stopped = 1; + + return 0; +} + +void ipc_server_free(struct ipc_server_data *server_data) +{ + struct ipc_accept_thread_data * accept_thread_data; + + if (!server_data) + return; + + if (!server_data->is_stopped) + BUG("cannot free ipc-server while running for '%s'", + server_data->buf_path.buf); + + accept_thread_data = server_data->accept_thread; + if (accept_thread_data) { + unix_ss_free(accept_thread_data->server_socket); + + if (accept_thread_data->fd_send_shutdown != -1) + close(accept_thread_data->fd_send_shutdown); + if (accept_thread_data->fd_wait_shutdown != -1) + close(accept_thread_data->fd_wait_shutdown); + + free(server_data->accept_thread); + } + + while (server_data->worker_thread_list) { + struct ipc_worker_thread_data *wtd = + server_data->worker_thread_list; + + server_data->worker_thread_list = wtd->next_thread; + free(wtd); + } + + pthread_cond_destroy(&server_data->work_available_cond); + pthread_mutex_destroy(&server_data->work_available_mutex); + + strbuf_release(&server_data->buf_path); + + free(server_data->fifo_fds); + free(server_data); +} diff --git a/compat/simple-ipc/ipc-win32.c b/compat/simple-ipc/ipc-win32.c new file mode 100644 index 0000000000..8f89c02037 --- /dev/null +++ b/compat/simple-ipc/ipc-win32.c @@ -0,0 +1,751 @@ +#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); +} diff --git a/config.mak.uname b/config.mak.uname index d204c20a64..cb443b4e02 100644 --- a/config.mak.uname +++ b/config.mak.uname @@ -424,6 +424,7 @@ ifeq ($(uname_S),Windows) RUNTIME_PREFIX = YesPlease HAVE_WPGMPTR = YesWeDo NO_ST_BLOCKS_IN_STRUCT_STAT = YesPlease + USE_WIN32_IPC = YesPlease USE_WIN32_MMAP = YesPlease MMAP_PREVENTS_DELETE = UnfortunatelyYes # USE_NED_ALLOCATOR = YesPlease @@ -600,6 +601,7 @@ ifneq (,$(findstring MINGW,$(uname_S))) RUNTIME_PREFIX = YesPlease HAVE_WPGMPTR = YesWeDo NO_ST_BLOCKS_IN_STRUCT_STAT = YesPlease + USE_WIN32_IPC = YesPlease USE_WIN32_MMAP = YesPlease MMAP_PREVENTS_DELETE = UnfortunatelyYes USE_NED_ALLOCATOR = YesPlease diff --git a/contrib/buildsystems/CMakeLists.txt b/contrib/buildsystems/CMakeLists.txt index ac3dbc079a..9897fcc8ea 100644 --- a/contrib/buildsystems/CMakeLists.txt +++ b/contrib/buildsystems/CMakeLists.txt @@ -243,7 +243,13 @@ if(CMAKE_SYSTEM_NAME STREQUAL "Windows") elseif(CMAKE_SYSTEM_NAME STREQUAL "Linux") add_compile_definitions(PROCFS_EXECUTABLE_PATH="/proc/self/exe" HAVE_DEV_TTY ) - list(APPEND compat_SOURCES unix-socket.c) + list(APPEND compat_SOURCES unix-socket.c unix-stream-server.c) +endif() + +if(CMAKE_SYSTEM_NAME STREQUAL "Windows") + list(APPEND compat_SOURCES compat/simple-ipc/ipc-shared.c compat/simple-ipc/ipc-win32.c) +else() + list(APPEND compat_SOURCES compat/simple-ipc/ipc-shared.c compat/simple-ipc/ipc-unix-socket.c) endif() set(EXE_EXTENSION ${CMAKE_EXECUTABLE_SUFFIX}) @@ -873,9 +873,13 @@ static int apply_multi_file_filter(const char *path, const char *src, size_t len goto done; if (fd >= 0) - err = write_packetized_from_fd(fd, process->in); + err = write_packetized_from_fd_no_flush(fd, process->in); else - err = write_packetized_from_buf(src, len, process->in); + err = write_packetized_from_buf_no_flush(src, len, process->in); + if (err) + goto done; + + err = packet_flush_gently(process->in); if (err) goto done; @@ -892,7 +896,8 @@ static int apply_multi_file_filter(const char *path, const char *src, size_t len if (err) goto done; - err = read_packetized_to_strbuf(process->out, &nbuf) < 0; + err = read_packetized_to_strbuf(process->out, &nbuf, + PACKET_READ_GENTLE_ON_EOF) < 0; if (err) goto done; diff --git a/pkt-line.c b/pkt-line.c index d633005ef7..0194137528 100644 --- a/pkt-line.c +++ b/pkt-line.c @@ -196,17 +196,26 @@ int packet_write_fmt_gently(int fd, const char *fmt, ...) static int packet_write_gently(const int fd_out, const char *buf, size_t size) { - static char packet_write_buffer[LARGE_PACKET_MAX]; + char header[4]; size_t packet_size; - if (size > sizeof(packet_write_buffer) - 4) + if (size > LARGE_PACKET_DATA_MAX) return error(_("packet write failed - data exceeds max packet size")); packet_trace(buf, size, 1); packet_size = size + 4; - set_packet_header(packet_write_buffer, packet_size); - memcpy(packet_write_buffer + 4, buf, size); - if (write_in_full(fd_out, packet_write_buffer, packet_size) < 0) + + set_packet_header(header, packet_size); + + /* + * Write the header and the buffer in 2 parts so that we do + * not need to allocate a buffer or rely on a static buffer. + * This also avoids putting a large buffer on the stack which + * might have multi-threading issues. + */ + + if (write_in_full(fd_out, header, 4) < 0 || + write_in_full(fd_out, buf, size) < 0) return error(_("packet write failed")); return 0; } @@ -242,26 +251,27 @@ void packet_buf_write_len(struct strbuf *buf, const char *data, size_t len) packet_trace(data, len, 1); } -int write_packetized_from_fd(int fd_in, int fd_out) +int write_packetized_from_fd_no_flush(int fd_in, int fd_out) { - static char buf[LARGE_PACKET_DATA_MAX]; + char *buf = xmalloc(LARGE_PACKET_DATA_MAX); int err = 0; ssize_t bytes_to_write; while (!err) { - bytes_to_write = xread(fd_in, buf, sizeof(buf)); - if (bytes_to_write < 0) + bytes_to_write = xread(fd_in, buf, LARGE_PACKET_DATA_MAX); + if (bytes_to_write < 0) { + free(buf); return COPY_READ_ERROR; + } if (bytes_to_write == 0) break; err = packet_write_gently(fd_out, buf, bytes_to_write); } - if (!err) - err = packet_flush_gently(fd_out); + free(buf); return err; } -int write_packetized_from_buf(const char *src_in, size_t len, int fd_out) +int write_packetized_from_buf_no_flush(const char *src_in, size_t len, int fd_out) { int err = 0; size_t bytes_written = 0; @@ -277,8 +287,6 @@ int write_packetized_from_buf(const char *src_in, size_t len, int fd_out) err = packet_write_gently(fd_out, src_in + bytes_written, bytes_to_write); bytes_written += bytes_to_write; } - if (!err) - err = packet_flush_gently(fd_out); return err; } @@ -298,8 +306,11 @@ static int get_packet_data(int fd, char **src_buf, size_t *src_size, *src_size -= ret; } else { ret = read_in_full(fd, dst, size); - if (ret < 0) + if (ret < 0) { + if (options & PACKET_READ_GENTLE_ON_READ_ERROR) + return error_errno(_("read error")); die_errno(_("read error")); + } } /* And complain if we didn't get enough bytes to satisfy the read. */ @@ -307,6 +318,8 @@ static int get_packet_data(int fd, char **src_buf, size_t *src_size, if (options & PACKET_READ_GENTLE_ON_EOF) return -1; + if (options & PACKET_READ_GENTLE_ON_READ_ERROR) + return error(_("the remote end hung up unexpectedly")); die(_("the remote end hung up unexpectedly")); } @@ -335,6 +348,9 @@ enum packet_read_status packet_read_with_status(int fd, char **src_buffer, len = packet_length(linelen); if (len < 0) { + if (options & PACKET_READ_GENTLE_ON_READ_ERROR) + return error(_("protocol error: bad line length " + "character: %.4s"), linelen); die(_("protocol error: bad line length character: %.4s"), linelen); } else if (!len) { packet_trace("0000", 4, 0); @@ -349,12 +365,19 @@ enum packet_read_status packet_read_with_status(int fd, char **src_buffer, *pktlen = 0; return PACKET_READ_RESPONSE_END; } else if (len < 4) { + if (options & PACKET_READ_GENTLE_ON_READ_ERROR) + return error(_("protocol error: bad line length %d"), + len); die(_("protocol error: bad line length %d"), len); } len -= 4; - if ((unsigned)len >= size) + if ((unsigned)len >= size) { + if (options & PACKET_READ_GENTLE_ON_READ_ERROR) + return error(_("protocol error: bad line length %d"), + len); die(_("protocol error: bad line length %d"), len); + } if (get_packet_data(fd, src_buffer, src_len, buffer, len, options) < 0) { *pktlen = -1; @@ -421,7 +444,7 @@ char *packet_read_line_buf(char **src, size_t *src_len, int *dst_len) return packet_read_line_generic(-1, src, src_len, dst_len); } -ssize_t read_packetized_to_strbuf(int fd_in, struct strbuf *sb_out) +ssize_t read_packetized_to_strbuf(int fd_in, struct strbuf *sb_out, int options) { int packet_len; @@ -437,7 +460,7 @@ ssize_t read_packetized_to_strbuf(int fd_in, struct strbuf *sb_out) * that there is already room for the extra byte. */ sb_out->buf + sb_out->len, LARGE_PACKET_DATA_MAX+1, - PACKET_READ_GENTLE_ON_EOF); + options); if (packet_len <= 0) break; sb_out->len += packet_len; diff --git a/pkt-line.h b/pkt-line.h index 8c90daa59e..5af5f45687 100644 --- a/pkt-line.h +++ b/pkt-line.h @@ -32,8 +32,8 @@ void packet_buf_write(struct strbuf *buf, const char *fmt, ...) __attribute__((f void packet_buf_write_len(struct strbuf *buf, const char *data, size_t len); int packet_flush_gently(int fd); int packet_write_fmt_gently(int fd, const char *fmt, ...) __attribute__((format (printf, 2, 3))); -int write_packetized_from_fd(int fd_in, int fd_out); -int write_packetized_from_buf(const char *src_in, size_t len, int fd_out); +int write_packetized_from_fd_no_flush(int fd_in, int fd_out); +int write_packetized_from_buf_no_flush(const char *src_in, size_t len, int fd_out); /* * Read a packetized line into the buffer, which must be at least size bytes @@ -68,10 +68,15 @@ int write_packetized_from_buf(const char *src_in, size_t len, int fd_out); * * If options contains PACKET_READ_DIE_ON_ERR_PACKET, it dies when it sees an * ERR packet. + * + * If options contains PACKET_READ_GENTLE_ON_READ_ERROR, we will not die + * on read errors, but instead return -1. However, we may still die on an + * ERR packet (if requested). */ -#define PACKET_READ_GENTLE_ON_EOF (1u<<0) -#define PACKET_READ_CHOMP_NEWLINE (1u<<1) -#define PACKET_READ_DIE_ON_ERR_PACKET (1u<<2) +#define PACKET_READ_GENTLE_ON_EOF (1u<<0) +#define PACKET_READ_CHOMP_NEWLINE (1u<<1) +#define PACKET_READ_DIE_ON_ERR_PACKET (1u<<2) +#define PACKET_READ_GENTLE_ON_READ_ERROR (1u<<3) int packet_read(int fd, char **src_buffer, size_t *src_len, char *buffer, unsigned size, int options); @@ -131,7 +136,7 @@ char *packet_read_line_buf(char **src_buf, size_t *src_len, int *size); /* * Reads a stream of variable sized packets until a flush packet is detected. */ -ssize_t read_packetized_to_strbuf(int fd_in, struct strbuf *sb_out); +ssize_t read_packetized_to_strbuf(int fd_in, struct strbuf *sb_out, int options); /* * Receive multiplexed output stream over git native protocol. diff --git a/simple-ipc.h b/simple-ipc.h new file mode 100644 index 0000000000..dc3606e30b --- /dev/null +++ b/simple-ipc.h @@ -0,0 +1,239 @@ +#ifndef GIT_SIMPLE_IPC_H +#define GIT_SIMPLE_IPC_H + +/* + * See Documentation/technical/api-simple-ipc.txt + */ + +#if defined(GIT_WINDOWS_NATIVE) || !defined(NO_UNIX_SOCKETS) +#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; + + /* + * Disallow chdir() when creating a Unix domain socket. + */ + unsigned int uds_disallow_chdir:1; +}; + +#define IPC_CLIENT_CONNECT_OPTIONS_INIT { \ + .wait_if_busy = 0, \ + .wait_if_not_found = 0, \ + .uds_disallow_chdir = 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; + + /* + * Disallow chdir() when creating a Unix domain socket. + */ + unsigned int uds_disallow_chdir:1; +}; + +/* + * 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 */ diff --git a/t/helper/test-simple-ipc.c b/t/helper/test-simple-ipc.c new file mode 100644 index 0000000000..42040ef81b --- /dev/null +++ b/t/helper/test-simple-ipc.c @@ -0,0 +1,787 @@ +/* + * test-simple-ipc.c: verify that the Inter-Process Communication works. + */ + +#include "test-tool.h" +#include "cache.h" +#include "strbuf.h" +#include "simple-ipc.h" +#include "parse-options.h" +#include "thread-utils.h" +#include "strvec.h" + +#ifndef SUPPORTS_SIMPLE_IPC +int cmd__simple_ipc(int argc, const char **argv) +{ + die("simple IPC not available on this platform"); +} +#else + +/* + * The test daemon defines an "application callback" that supports a + * series of commands (see `test_app_cb()`). + * + * Unknown commands are caught here and we send an error message back + * to the client process. + */ +static int app__unhandled_command(const char *command, + ipc_server_reply_cb *reply_cb, + struct ipc_server_reply_data *reply_data) +{ + struct strbuf buf = STRBUF_INIT; + int ret; + + strbuf_addf(&buf, "unhandled command: %s", command); + ret = reply_cb(reply_data, buf.buf, buf.len); + strbuf_release(&buf); + + return ret; +} + +/* + * Reply with a single very large buffer. This is to ensure that + * long response are properly handled -- whether the chunking occurs + * in the kernel or in the (probably pkt-line) layer. + */ +#define BIG_ROWS (10000) +static int app__big_command(ipc_server_reply_cb *reply_cb, + struct ipc_server_reply_data *reply_data) +{ + struct strbuf buf = STRBUF_INIT; + int row; + int ret; + + for (row = 0; row < BIG_ROWS; row++) + strbuf_addf(&buf, "big: %.75d\n", row); + + ret = reply_cb(reply_data, buf.buf, buf.len); + strbuf_release(&buf); + + return ret; +} + +/* + * Reply with a series of lines. This is to ensure that we can incrementally + * compute the response and chunk it to the client. + */ +#define CHUNK_ROWS (10000) +static int app__chunk_command(ipc_server_reply_cb *reply_cb, + struct ipc_server_reply_data *reply_data) +{ + struct strbuf buf = STRBUF_INIT; + int row; + int ret; + + for (row = 0; row < CHUNK_ROWS; row++) { + strbuf_setlen(&buf, 0); + strbuf_addf(&buf, "big: %.75d\n", row); + ret = reply_cb(reply_data, buf.buf, buf.len); + } + + strbuf_release(&buf); + + return ret; +} + +/* + * Slowly reply with a series of lines. This is to model an expensive to + * compute chunked response (which might happen if this callback is running + * in a thread and is fighting for a lock with other threads). + */ +#define SLOW_ROWS (1000) +#define SLOW_DELAY_MS (10) +static int app__slow_command(ipc_server_reply_cb *reply_cb, + struct ipc_server_reply_data *reply_data) +{ + struct strbuf buf = STRBUF_INIT; + int row; + int ret; + + for (row = 0; row < SLOW_ROWS; row++) { + strbuf_setlen(&buf, 0); + strbuf_addf(&buf, "big: %.75d\n", row); + ret = reply_cb(reply_data, buf.buf, buf.len); + sleep_millisec(SLOW_DELAY_MS); + } + + strbuf_release(&buf); + + return ret; +} + +/* + * The client sent a command followed by a (possibly very) large buffer. + */ +static int app__sendbytes_command(const char *received, + ipc_server_reply_cb *reply_cb, + struct ipc_server_reply_data *reply_data) +{ + struct strbuf buf_resp = STRBUF_INIT; + const char *p = "?"; + int len_ballast = 0; + int k; + int errs = 0; + int ret; + + if (skip_prefix(received, "sendbytes ", &p)) + len_ballast = strlen(p); + + /* + * Verify that the ballast is n copies of a single letter. + * And that the multi-threaded IO layer didn't cross the streams. + */ + for (k = 1; k < len_ballast; k++) + if (p[k] != p[0]) + errs++; + + if (errs) + strbuf_addf(&buf_resp, "errs:%d\n", errs); + else + strbuf_addf(&buf_resp, "rcvd:%c%08d\n", p[0], len_ballast); + + ret = reply_cb(reply_data, buf_resp.buf, buf_resp.len); + + strbuf_release(&buf_resp); + + return ret; +} + +/* + * An arbitrary fixed address to verify that the application instance + * data is handled properly. + */ +static int my_app_data = 42; + +static ipc_server_application_cb test_app_cb; + +/* + * This is the "application callback" that sits on top of the + * "ipc-server". It completely defines the set of commands supported + * by this application. + */ +static int test_app_cb(void *application_data, + const char *command, + ipc_server_reply_cb *reply_cb, + struct ipc_server_reply_data *reply_data) +{ + /* + * Verify that we received the application-data that we passed + * when we started the ipc-server. (We have several layers of + * callbacks calling callbacks and it's easy to get things mixed + * up (especially when some are "void*").) + */ + if (application_data != (void*)&my_app_data) + BUG("application_cb: application_data pointer wrong"); + + if (!strcmp(command, "quit")) { + /* + * The client sent a "quit" command. This is an async + * request for the server to shutdown. + * + * We DO NOT send the client a response message + * (because we have nothing to say and the other + * server threads have not yet stopped). + * + * Tell the ipc-server layer to start shutting down. + * This includes: stop listening for new connections + * on the socket/pipe and telling all worker threads + * to finish/drain their outgoing responses to other + * clients. + * + * This DOES NOT force an immediate sync shutdown. + */ + return SIMPLE_IPC_QUIT; + } + + if (!strcmp(command, "ping")) { + const char *answer = "pong"; + return reply_cb(reply_data, answer, strlen(answer)); + } + + if (!strcmp(command, "big")) + return app__big_command(reply_cb, reply_data); + + if (!strcmp(command, "chunk")) + return app__chunk_command(reply_cb, reply_data); + + if (!strcmp(command, "slow")) + return app__slow_command(reply_cb, reply_data); + + if (starts_with(command, "sendbytes ")) + return app__sendbytes_command(command, reply_cb, reply_data); + + return app__unhandled_command(command, reply_cb, reply_data); +} + +struct cl_args +{ + const char *subcommand; + const char *path; + const char *token; + + int nr_threads; + int max_wait_sec; + int bytecount; + int batchsize; + + char bytevalue; +}; + +static struct cl_args cl_args = { + .subcommand = NULL, + .path = "ipc-test", + .token = NULL, + + .nr_threads = 5, + .max_wait_sec = 60, + .bytecount = 1024, + .batchsize = 10, + + .bytevalue = 'x', +}; + +/* + * This process will run as a simple-ipc server and listen for IPC commands + * from client processes. + */ +static int daemon__run_server(void) +{ + int ret; + + struct ipc_server_opts opts = { + .nr_threads = cl_args.nr_threads, + }; + + /* + * Synchronously run the ipc-server. We don't need any application + * instance data, so pass an arbitrary pointer (that we'll later + * verify made the round trip). + */ + ret = ipc_server_run(cl_args.path, &opts, test_app_cb, (void*)&my_app_data); + if (ret == -2) + error(_("socket/pipe already in use: '%s'"), cl_args.path); + else if (ret == -1) + error_errno(_("could not start server on: '%s'"), cl_args.path); + + return ret; +} + +#ifndef GIT_WINDOWS_NATIVE +/* + * This is adapted from `daemonize()`. Use `fork()` to directly create and + * run the daemon in a child process. + */ +static int spawn_server(pid_t *pid) +{ + struct ipc_server_opts opts = { + .nr_threads = cl_args.nr_threads, + }; + + *pid = fork(); + + switch (*pid) { + case 0: + if (setsid() == -1) + error_errno(_("setsid failed")); + close(0); + close(1); + close(2); + sanitize_stdfds(); + + return ipc_server_run(cl_args.path, &opts, test_app_cb, + (void*)&my_app_data); + + case -1: + return error_errno(_("could not spawn daemon in the background")); + + default: + return 0; + } +} +#else +/* + * Conceptually like `daemonize()` but different because Windows does not + * have `fork(2)`. Spawn a normal Windows child process but without the + * limitations of `start_command()` and `finish_command()`. + */ +static int spawn_server(pid_t *pid) +{ + char test_tool_exe[MAX_PATH]; + struct strvec args = STRVEC_INIT; + int in, out; + + GetModuleFileNameA(NULL, test_tool_exe, MAX_PATH); + + in = open("/dev/null", O_RDONLY); + out = open("/dev/null", O_WRONLY); + + strvec_push(&args, test_tool_exe); + strvec_push(&args, "simple-ipc"); + strvec_push(&args, "run-daemon"); + strvec_pushf(&args, "--name=%s", cl_args.path); + strvec_pushf(&args, "--threads=%d", cl_args.nr_threads); + + *pid = mingw_spawnvpe(args.v[0], args.v, NULL, NULL, in, out, out); + close(in); + close(out); + + strvec_clear(&args); + + if (*pid < 0) + return error(_("could not spawn daemon in the background")); + + return 0; +} +#endif + +/* + * This is adapted from `wait_or_whine()`. Watch the child process and + * let it get started and begin listening for requests on the socket + * before reporting our success. + */ +static int wait_for_server_startup(pid_t pid_child) +{ + int status; + pid_t pid_seen; + enum ipc_active_state s; + time_t time_limit, now; + + time(&time_limit); + time_limit += cl_args.max_wait_sec; + + for (;;) { + pid_seen = waitpid(pid_child, &status, WNOHANG); + + if (pid_seen == -1) + return error_errno(_("waitpid failed")); + + else if (pid_seen == 0) { + /* + * The child is still running (this should be + * the normal case). Try to connect to it on + * the socket and see if it is ready for + * business. + * + * If there is another daemon already running, + * our child will fail to start (possibly + * after a timeout on the lock), but we don't + * care (who responds) if the socket is live. + */ + s = ipc_get_active_state(cl_args.path); + if (s == IPC_STATE__LISTENING) + return 0; + + time(&now); + if (now > time_limit) + return error(_("daemon not online yet")); + + continue; + } + + else if (pid_seen == pid_child) { + /* + * The new child daemon process shutdown while + * it was starting up, so it is not listening + * on the socket. + * + * Try to ping the socket in the odd chance + * that another daemon started (or was already + * running) while our child was starting. + * + * Again, we don't care who services the socket. + */ + s = ipc_get_active_state(cl_args.path); + if (s == IPC_STATE__LISTENING) + return 0; + + /* + * We don't care about the WEXITSTATUS() nor + * any of the WIF*(status) values because + * `cmd__simple_ipc()` does the `!!result` + * trick on all function return values. + * + * So it is sufficient to just report the + * early shutdown as an error. + */ + return error(_("daemon failed to start")); + } + + else + return error(_("waitpid is confused")); + } +} + +/* + * This process will start a simple-ipc server in a background process and + * wait for it to become ready. This is like `daemonize()` but gives us + * more control and better error reporting (and makes it easier to write + * unit tests). + */ +static int daemon__start_server(void) +{ + pid_t pid_child; + int ret; + + /* + * Run the actual daemon in a background process. + */ + ret = spawn_server(&pid_child); + if (pid_child <= 0) + return ret; + + /* + * Let the parent wait for the child process to get started + * and begin listening for requests on the socket. + */ + ret = wait_for_server_startup(pid_child); + + return ret; +} + +/* + * This process will run a quick probe to see if a simple-ipc server + * is active on this path. + * + * Returns 0 if the server is alive. + */ +static int client__probe_server(void) +{ + enum ipc_active_state s; + + s = ipc_get_active_state(cl_args.path); + switch (s) { + case IPC_STATE__LISTENING: + return 0; + + case IPC_STATE__NOT_LISTENING: + return error("no server listening at '%s'", cl_args.path); + + case IPC_STATE__PATH_NOT_FOUND: + return error("path not found '%s'", cl_args.path); + + case IPC_STATE__INVALID_PATH: + return error("invalid pipe/socket name '%s'", cl_args.path); + + case IPC_STATE__OTHER_ERROR: + default: + return error("other error for '%s'", cl_args.path); + } +} + +/* + * Send an IPC command token to an already-running server daemon and + * print the response. + * + * This is a simple 1 word command/token that `test_app_cb()` (in the + * daemon process) will understand. + */ +static int client__send_ipc(void) +{ + const char *command = "(no-command)"; + struct strbuf buf = STRBUF_INIT; + struct ipc_client_connect_options options + = IPC_CLIENT_CONNECT_OPTIONS_INIT; + + if (cl_args.token && *cl_args.token) + command = cl_args.token; + + options.wait_if_busy = 1; + options.wait_if_not_found = 0; + + if (!ipc_client_send_command(cl_args.path, &options, command, &buf)) { + if (buf.len) { + printf("%s\n", buf.buf); + fflush(stdout); + } + strbuf_release(&buf); + + return 0; + } + + return error("failed to send '%s' to '%s'", command, cl_args.path); +} + +/* + * Send an IPC command to an already-running server and ask it to + * shutdown. "send quit" is an async request and queues a shutdown + * event in the server, so we spin and wait here for it to actually + * shutdown to make the unit tests a little easier to write. + */ +static int client__stop_server(void) +{ + int ret; + time_t time_limit, now; + enum ipc_active_state s; + + time(&time_limit); + time_limit += cl_args.max_wait_sec; + + cl_args.token = "quit"; + + ret = client__send_ipc(); + if (ret) + return ret; + + for (;;) { + sleep_millisec(100); + + s = ipc_get_active_state(cl_args.path); + + if (s != IPC_STATE__LISTENING) { + /* + * The socket/pipe is gone and/or has stopped + * responding. Lets assume that the daemon + * process has exited too. + */ + return 0; + } + + time(&now); + if (now > time_limit) + return error(_("daemon has not shutdown yet")); + } +} + +/* + * Send an IPC command followed by ballast to confirm that a large + * message can be sent and that the kernel or pkt-line layers will + * properly chunk it and that the daemon receives the entire message. + */ +static int do_sendbytes(int bytecount, char byte, const char *path, + const struct ipc_client_connect_options *options) +{ + struct strbuf buf_send = STRBUF_INIT; + struct strbuf buf_resp = STRBUF_INIT; + + strbuf_addstr(&buf_send, "sendbytes "); + strbuf_addchars(&buf_send, byte, bytecount); + + if (!ipc_client_send_command(path, options, buf_send.buf, &buf_resp)) { + strbuf_rtrim(&buf_resp); + printf("sent:%c%08d %s\n", byte, bytecount, buf_resp.buf); + fflush(stdout); + strbuf_release(&buf_send); + strbuf_release(&buf_resp); + + return 0; + } + + return error("client failed to sendbytes(%d, '%c') to '%s'", + bytecount, byte, path); +} + +/* + * Send an IPC command with ballast to an already-running server daemon. + */ +static int client__sendbytes(void) +{ + struct ipc_client_connect_options options + = IPC_CLIENT_CONNECT_OPTIONS_INIT; + + options.wait_if_busy = 1; + options.wait_if_not_found = 0; + options.uds_disallow_chdir = 0; + + return do_sendbytes(cl_args.bytecount, cl_args.bytevalue, cl_args.path, + &options); +} + +struct multiple_thread_data { + pthread_t pthread_id; + struct multiple_thread_data *next; + const char *path; + int bytecount; + int batchsize; + int sum_errors; + int sum_good; + char letter; +}; + +static void *multiple_thread_proc(void *_multiple_thread_data) +{ + struct multiple_thread_data *d = _multiple_thread_data; + int k; + struct ipc_client_connect_options options + = IPC_CLIENT_CONNECT_OPTIONS_INIT; + + options.wait_if_busy = 1; + options.wait_if_not_found = 0; + /* + * A multi-threaded client should not be randomly calling chdir(). + * The test will pass without this restriction because the test is + * not otherwise accessing the filesystem, but it makes us honest. + */ + options.uds_disallow_chdir = 1; + + trace2_thread_start("multiple"); + + for (k = 0; k < d->batchsize; k++) { + if (do_sendbytes(d->bytecount + k, d->letter, d->path, &options)) + d->sum_errors++; + else + d->sum_good++; + } + + trace2_thread_exit(); + return NULL; +} + +/* + * Start a client-side thread pool. Each thread sends a series of + * IPC requests. Each request is on a new connection to the server. + */ +static int client__multiple(void) +{ + struct multiple_thread_data *list = NULL; + int k; + int sum_join_errors = 0; + int sum_thread_errors = 0; + int sum_good = 0; + + for (k = 0; k < cl_args.nr_threads; k++) { + struct multiple_thread_data *d = xcalloc(1, sizeof(*d)); + d->next = list; + d->path = cl_args.path; + d->bytecount = cl_args.bytecount + cl_args.batchsize*(k/26); + d->batchsize = cl_args.batchsize; + d->sum_errors = 0; + d->sum_good = 0; + d->letter = 'A' + (k % 26); + + if (pthread_create(&d->pthread_id, NULL, multiple_thread_proc, d)) { + warning("failed to create thread[%d] skipping remainder", k); + free(d); + break; + } + + list = d; + } + + while (list) { + struct multiple_thread_data *d = list; + + if (pthread_join(d->pthread_id, NULL)) + sum_join_errors++; + + sum_thread_errors += d->sum_errors; + sum_good += d->sum_good; + + list = d->next; + free(d); + } + + printf("client (good %d) (join %d), (errors %d)\n", + sum_good, sum_join_errors, sum_thread_errors); + + return (sum_join_errors + sum_thread_errors) ? 1 : 0; +} + +int cmd__simple_ipc(int argc, const char **argv) +{ + const char * const simple_ipc_usage[] = { + N_("test-helper simple-ipc is-active [<name>] [<options>]"), + N_("test-helper simple-ipc run-daemon [<name>] [<threads>]"), + N_("test-helper simple-ipc start-daemon [<name>] [<threads>] [<max-wait>]"), + N_("test-helper simple-ipc stop-daemon [<name>] [<max-wait>]"), + N_("test-helper simple-ipc send [<name>] [<token>]"), + N_("test-helper simple-ipc sendbytes [<name>] [<bytecount>] [<byte>]"), + N_("test-helper simple-ipc multiple [<name>] [<threads>] [<bytecount>] [<batchsize>]"), + NULL + }; + + const char *bytevalue = NULL; + + struct option options[] = { +#ifndef GIT_WINDOWS_NATIVE + OPT_STRING(0, "name", &cl_args.path, N_("name"), N_("name or pathname of unix domain socket")), +#else + OPT_STRING(0, "name", &cl_args.path, N_("name"), N_("named-pipe name")), +#endif + OPT_INTEGER(0, "threads", &cl_args.nr_threads, N_("number of threads in server thread pool")), + OPT_INTEGER(0, "max-wait", &cl_args.max_wait_sec, N_("seconds to wait for daemon to start or stop")), + + OPT_INTEGER(0, "bytecount", &cl_args.bytecount, N_("number of bytes")), + OPT_INTEGER(0, "batchsize", &cl_args.batchsize, N_("number of requests per thread")), + + OPT_STRING(0, "byte", &bytevalue, N_("byte"), N_("ballast character")), + OPT_STRING(0, "token", &cl_args.token, N_("token"), N_("command token to send to the server")), + + OPT_END() + }; + + if (argc < 2) + usage_with_options(simple_ipc_usage, options); + + if (argc == 2 && !strcmp(argv[1], "-h")) + usage_with_options(simple_ipc_usage, options); + + if (argc == 2 && !strcmp(argv[1], "SUPPORTS_SIMPLE_IPC")) + return 0; + + cl_args.subcommand = argv[1]; + + argc--; + argv++; + + argc = parse_options(argc, argv, NULL, options, simple_ipc_usage, 0); + + if (cl_args.nr_threads < 1) + cl_args.nr_threads = 1; + if (cl_args.max_wait_sec < 0) + cl_args.max_wait_sec = 0; + if (cl_args.bytecount < 1) + cl_args.bytecount = 1; + if (cl_args.batchsize < 1) + cl_args.batchsize = 1; + + if (bytevalue && *bytevalue) + cl_args.bytevalue = bytevalue[0]; + + /* + * Use '!!' on all dispatch functions to map from `error()` style + * (returns -1) style to `test_must_fail` style (expects 1). This + * makes shell error messages less confusing. + */ + + if (!strcmp(cl_args.subcommand, "is-active")) + return !!client__probe_server(); + + if (!strcmp(cl_args.subcommand, "run-daemon")) + return !!daemon__run_server(); + + if (!strcmp(cl_args.subcommand, "start-daemon")) + return !!daemon__start_server(); + + /* + * Client commands follow. Ensure a server is running before + * sending any data. This might be overkill, but then again + * this is a test harness. + */ + + if (!strcmp(cl_args.subcommand, "stop-daemon")) { + if (client__probe_server()) + return 1; + return !!client__stop_server(); + } + + if (!strcmp(cl_args.subcommand, "send")) { + if (client__probe_server()) + return 1; + return !!client__send_ipc(); + } + + if (!strcmp(cl_args.subcommand, "sendbytes")) { + if (client__probe_server()) + return 1; + return !!client__sendbytes(); + } + + if (!strcmp(cl_args.subcommand, "multiple")) { + if (client__probe_server()) + return 1; + return !!client__multiple(); + } + + die("Unhandled subcommand: '%s'", cl_args.subcommand); +} +#endif diff --git a/t/helper/test-tool.c b/t/helper/test-tool.c index f97cd9f48a..287aa60023 100644 --- a/t/helper/test-tool.c +++ b/t/helper/test-tool.c @@ -65,6 +65,7 @@ static struct test_cmd cmds[] = { { "sha1", cmd__sha1 }, { "sha256", cmd__sha256 }, { "sigchain", cmd__sigchain }, + { "simple-ipc", cmd__simple_ipc }, { "strcmp-offset", cmd__strcmp_offset }, { "string-list", cmd__string_list }, { "submodule-config", cmd__submodule_config }, diff --git a/t/helper/test-tool.h b/t/helper/test-tool.h index 28072c0ad5..9ea4b31011 100644 --- a/t/helper/test-tool.h +++ b/t/helper/test-tool.h @@ -55,6 +55,7 @@ int cmd__sha1(int argc, const char **argv); int cmd__oid_array(int argc, const char **argv); int cmd__sha256(int argc, const char **argv); int cmd__sigchain(int argc, const char **argv); +int cmd__simple_ipc(int argc, const char **argv); int cmd__strcmp_offset(int argc, const char **argv); int cmd__string_list(int argc, const char **argv); int cmd__submodule_config(int argc, const char **argv); diff --git a/t/t0052-simple-ipc.sh b/t/t0052-simple-ipc.sh new file mode 100755 index 0000000000..ff98be31a5 --- /dev/null +++ b/t/t0052-simple-ipc.sh @@ -0,0 +1,122 @@ +#!/bin/sh + +test_description='simple command server' + +. ./test-lib.sh + +test-tool simple-ipc SUPPORTS_SIMPLE_IPC || { + skip_all='simple IPC not supported on this platform' + test_done +} + +stop_simple_IPC_server () { + test-tool simple-ipc stop-daemon +} + +test_expect_success 'start simple command server' ' + test_atexit stop_simple_IPC_server && + test-tool simple-ipc start-daemon --threads=8 && + test-tool simple-ipc is-active +' + +test_expect_success 'simple command server' ' + test-tool simple-ipc send --token=ping >actual && + echo pong >expect && + test_cmp expect actual +' + +test_expect_success 'servers cannot share the same path' ' + test_must_fail test-tool simple-ipc run-daemon && + test-tool simple-ipc is-active +' + +test_expect_success 'big response' ' + test-tool simple-ipc send --token=big >actual && + test_line_count -ge 10000 actual && + grep -q "big: [0]*9999\$" actual +' + +test_expect_success 'chunk response' ' + test-tool simple-ipc send --token=chunk >actual && + test_line_count -ge 10000 actual && + grep -q "big: [0]*9999\$" actual +' + +test_expect_success 'slow response' ' + test-tool simple-ipc send --token=slow >actual && + test_line_count -ge 100 actual && + grep -q "big: [0]*99\$" actual +' + +# Send an IPC with n=100,000 bytes of ballast. This should be large enough +# to force both the kernel and the pkt-line layer to chunk the message to the +# daemon and for the daemon to receive it in chunks. +# +test_expect_success 'sendbytes' ' + test-tool simple-ipc sendbytes --bytecount=100000 --byte=A >actual && + grep "sent:A00100000 rcvd:A00100000" actual +' + +# Start a series of <threads> client threads that each make <batchsize> +# IPC requests to the server. Each (<threads> * <batchsize>) request +# will open a new connection to the server and randomly bind to a server +# thread. Each client thread exits after completing its batch. So the +# total number of live client threads will be smaller than the total. +# Each request will send a message containing at least <bytecount> bytes +# of ballast. (Responses are small.) +# +# The purpose here is to test threading in the server and responding to +# many concurrent client requests (regardless of whether they come from +# 1 client process or many). And to test that the server side of the +# named pipe/socket is stable. (On Windows this means that the server +# pipe is properly recycled.) +# +# On Windows it also lets us adjust the connection timeout in the +# `ipc_client_send_command()`. +# +# Note it is easy to drive the system into failure by requesting an +# insane number of threads on client or server and/or increasing the +# per-thread batchsize or the per-request bytecount (ballast). +# On Windows these failures look like "pipe is busy" errors. +# So I've chosen fairly conservative values for now. +# +# We expect output of the form "sent:<letter><length> ..." +# With terms (7, 19, 13) we expect: +# <letter> in [A-G] +# <length> in [19+0 .. 19+(13-1)] +# and (7 * 13) successful responses. +# +test_expect_success 'stress test threads' ' + test-tool simple-ipc multiple \ + --threads=7 \ + --bytecount=19 \ + --batchsize=13 \ + >actual && + test_line_count = 92 actual && + grep "good 91" actual && + grep "sent:A" <actual >actual_a && + cat >expect_a <<-EOF && + sent:A00000019 rcvd:A00000019 + sent:A00000020 rcvd:A00000020 + sent:A00000021 rcvd:A00000021 + sent:A00000022 rcvd:A00000022 + sent:A00000023 rcvd:A00000023 + sent:A00000024 rcvd:A00000024 + sent:A00000025 rcvd:A00000025 + sent:A00000026 rcvd:A00000026 + sent:A00000027 rcvd:A00000027 + sent:A00000028 rcvd:A00000028 + sent:A00000029 rcvd:A00000029 + sent:A00000030 rcvd:A00000030 + sent:A00000031 rcvd:A00000031 + EOF + test_cmp expect_a actual_a +' + +test_expect_success 'stop-daemon works' ' + test-tool simple-ipc stop-daemon && + test_must_fail test-tool simple-ipc is-active && + test_must_fail test-tool simple-ipc send --token=ping +' + +test_done diff --git a/unix-socket.c b/unix-socket.c index 19ed48be99..e0be1badb5 100644 --- a/unix-socket.c +++ b/unix-socket.c @@ -1,13 +1,7 @@ #include "cache.h" #include "unix-socket.h" -static int unix_stream_socket(void) -{ - int fd = socket(AF_UNIX, SOCK_STREAM, 0); - if (fd < 0) - die_errno("unable to create socket"); - return fd; -} +#define DEFAULT_UNIX_STREAM_LISTEN_BACKLOG (5) static int chdir_len(const char *orig, int len) { @@ -36,16 +30,23 @@ static void unix_sockaddr_cleanup(struct unix_sockaddr_context *ctx) } static int unix_sockaddr_init(struct sockaddr_un *sa, const char *path, - struct unix_sockaddr_context *ctx) + struct unix_sockaddr_context *ctx, + int disallow_chdir) { int size = strlen(path) + 1; ctx->orig_dir = NULL; if (size > sizeof(sa->sun_path)) { - const char *slash = find_last_dir_sep(path); + const char *slash; const char *dir; struct strbuf cwd = STRBUF_INIT; + if (disallow_chdir) { + errno = ENAMETOOLONG; + return -1; + } + + slash = find_last_dir_sep(path); if (!slash) { errno = ENAMETOOLONG; return -1; @@ -71,15 +72,18 @@ static int unix_sockaddr_init(struct sockaddr_un *sa, const char *path, return 0; } -int unix_stream_connect(const char *path) +int unix_stream_connect(const char *path, int disallow_chdir) { - int fd, saved_errno; + int fd = -1, saved_errno; struct sockaddr_un sa; struct unix_sockaddr_context ctx; - if (unix_sockaddr_init(&sa, path, &ctx) < 0) + if (unix_sockaddr_init(&sa, path, &ctx, disallow_chdir) < 0) return -1; - fd = unix_stream_socket(); + fd = socket(AF_UNIX, SOCK_STREAM, 0); + if (fd < 0) + goto fail; + if (connect(fd, (struct sockaddr *)&sa, sizeof(sa)) < 0) goto fail; unix_sockaddr_cleanup(&ctx); @@ -87,28 +91,36 @@ int unix_stream_connect(const char *path) fail: saved_errno = errno; + if (fd != -1) + close(fd); unix_sockaddr_cleanup(&ctx); - close(fd); errno = saved_errno; return -1; } -int unix_stream_listen(const char *path) +int unix_stream_listen(const char *path, + const struct unix_stream_listen_opts *opts) { - int fd, saved_errno; + int fd = -1, saved_errno; + int backlog; struct sockaddr_un sa; struct unix_sockaddr_context ctx; unlink(path); - if (unix_sockaddr_init(&sa, path, &ctx) < 0) + if (unix_sockaddr_init(&sa, path, &ctx, opts->disallow_chdir) < 0) return -1; - fd = unix_stream_socket(); + fd = socket(AF_UNIX, SOCK_STREAM, 0); + if (fd < 0) + goto fail; if (bind(fd, (struct sockaddr *)&sa, sizeof(sa)) < 0) goto fail; - if (listen(fd, 5) < 0) + backlog = opts->listen_backlog_size; + if (backlog <= 0) + backlog = DEFAULT_UNIX_STREAM_LISTEN_BACKLOG; + if (listen(fd, backlog) < 0) goto fail; unix_sockaddr_cleanup(&ctx); @@ -116,8 +128,9 @@ int unix_stream_listen(const char *path) fail: saved_errno = errno; + if (fd != -1) + close(fd); unix_sockaddr_cleanup(&ctx); - close(fd); errno = saved_errno; return -1; } diff --git a/unix-socket.h b/unix-socket.h index e271aeec5a..8542cdd799 100644 --- a/unix-socket.h +++ b/unix-socket.h @@ -1,7 +1,15 @@ #ifndef UNIX_SOCKET_H #define UNIX_SOCKET_H -int unix_stream_connect(const char *path); -int unix_stream_listen(const char *path); +struct unix_stream_listen_opts { + int listen_backlog_size; + unsigned int disallow_chdir:1; +}; + +#define UNIX_STREAM_LISTEN_OPTS_INIT { 0 } + +int unix_stream_connect(const char *path, int disallow_chdir); +int unix_stream_listen(const char *path, + const struct unix_stream_listen_opts *opts); #endif /* UNIX_SOCKET_H */ diff --git a/unix-stream-server.c b/unix-stream-server.c new file mode 100644 index 0000000000..efa2a207ab --- /dev/null +++ b/unix-stream-server.c @@ -0,0 +1,125 @@ +#include "cache.h" +#include "lockfile.h" +#include "unix-socket.h" +#include "unix-stream-server.h" + +#define DEFAULT_LOCK_TIMEOUT (100) + +/* + * Try to connect to a unix domain socket at `path` (if it exists) and + * see if there is a server listening. + * + * We don't know if the socket exists, whether a server died and + * failed to cleanup, or whether we have a live server listening, so + * we "poke" it. + * + * We immediately hangup without sending/receiving any data because we + * don't know anything about the protocol spoken and don't want to + * block while writing/reading data. It is sufficient to just know + * that someone is listening. + */ +static int is_another_server_alive(const char *path, + const struct unix_stream_listen_opts *opts) +{ + int fd = unix_stream_connect(path, opts->disallow_chdir); + if (fd >= 0) { + close(fd); + return 1; + } + + return 0; +} + +int unix_ss_create(const char *path, + const struct unix_stream_listen_opts *opts, + long timeout_ms, + struct unix_ss_socket **new_server_socket) +{ + struct lock_file lock = LOCK_INIT; + int fd_socket; + struct unix_ss_socket *server_socket; + + *new_server_socket = NULL; + + if (timeout_ms < 0) + timeout_ms = DEFAULT_LOCK_TIMEOUT; + + /* + * Create a lock at "<path>.lock" if we can. + */ + if (hold_lock_file_for_update_timeout(&lock, path, 0, timeout_ms) < 0) + return -1; + + /* + * If another server is listening on "<path>" give up. We do not + * want to create a socket and steal future connections from them. + */ + if (is_another_server_alive(path, opts)) { + rollback_lock_file(&lock); + errno = EADDRINUSE; + return -2; + } + + /* + * Create and bind to a Unix domain socket at "<path>". + */ + fd_socket = unix_stream_listen(path, opts); + if (fd_socket < 0) { + int saved_errno = errno; + rollback_lock_file(&lock); + errno = saved_errno; + return -1; + } + + server_socket = xcalloc(1, sizeof(*server_socket)); + server_socket->path_socket = strdup(path); + server_socket->fd_socket = fd_socket; + lstat(path, &server_socket->st_socket); + + *new_server_socket = server_socket; + + /* + * Always rollback (just delete) "<path>.lock" because we already created + * "<path>" as a socket and do not want to commit_lock to do the atomic + * rename trick. + */ + rollback_lock_file(&lock); + + return 0; +} + +void unix_ss_free(struct unix_ss_socket *server_socket) +{ + if (!server_socket) + return; + + if (server_socket->fd_socket >= 0) { + if (!unix_ss_was_stolen(server_socket)) + unlink(server_socket->path_socket); + close(server_socket->fd_socket); + } + + free(server_socket->path_socket); + free(server_socket); +} + +int unix_ss_was_stolen(struct unix_ss_socket *server_socket) +{ + struct stat st_now; + + if (!server_socket) + return 0; + + if (lstat(server_socket->path_socket, &st_now) == -1) + return 1; + + if (st_now.st_ino != server_socket->st_socket.st_ino) + return 1; + if (st_now.st_dev != server_socket->st_socket.st_dev) + return 1; + + if (!S_ISSOCK(st_now.st_mode)) + return 1; + + return 0; +} diff --git a/unix-stream-server.h b/unix-stream-server.h new file mode 100644 index 0000000000..ae2712ba39 --- /dev/null +++ b/unix-stream-server.h @@ -0,0 +1,33 @@ +#ifndef UNIX_STREAM_SERVER_H +#define UNIX_STREAM_SERVER_H + +#include "unix-socket.h" + +struct unix_ss_socket { + char *path_socket; + struct stat st_socket; + int fd_socket; +}; + +/* + * Create a Unix Domain Socket at the given path under the protection + * of a '.lock' lockfile. + * + * Returns 0 on success, -1 on error, -2 if socket is in use. + */ +int unix_ss_create(const char *path, + const struct unix_stream_listen_opts *opts, + long timeout_ms, + struct unix_ss_socket **server_socket); + +/* + * Close and delete the socket. + */ +void unix_ss_free(struct unix_ss_socket *server_socket); + +/* + * Return 1 if the inode of the pathname to our socket changes. + */ +int unix_ss_was_stolen(struct unix_ss_socket *server_socket); + +#endif /* UNIX_STREAM_SERVER_H */ |