blob: 8f89c02037e36c9edba263a83882d147e463bbff [file] [log] [blame]
#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);
}