2 * General mechanism for wrapping up reading/writing of Windows
3 * HANDLEs into a PuTTY Socket abstraction.
10 #define DEFINE_PLUG_METHOD_MACROS
15 typedef struct Socket_handle_tag *Handle_Socket;
17 struct Socket_handle_tag {
18 const struct socket_function_table *fn;
19 /* the above variable absolutely *must* be the first in this structure */
21 HANDLE send_H, recv_H, stderr_H;
22 struct handle *send_h, *recv_h, *stderr_h;
25 * Freezing one of these sockets is a slightly fiddly business,
26 * because the reads from the handle are happening in a separate
27 * thread as blocking system calls and so once one is in progress
28 * it can't sensibly be interrupted. Hence, after the user tries
29 * to freeze one of these sockets, it's unavoidable that we may
30 * receive one more load of data before we manage to get
31 * winhandl.c to stop reading.
34 UNFROZEN, /* reading as normal */
35 FREEZING, /* have been set to frozen but winhandl is still reading */
36 FROZEN, /* really frozen - winhandl has been throttled */
37 THAWING /* we're gradually releasing our remaining data */
39 /* We buffer data here if we receive it from winhandl while frozen. */
42 /* Data received from stderr_H, if we have one. */
45 int defer_close, deferred_close; /* in case of re-entrance */
52 static int handle_gotdata(struct handle *h, void *data, int len)
54 Handle_Socket ps = (Handle_Socket) handle_get_privdata(h);
57 return plug_closing(ps->plug, "Read error from handle",
59 } else if (len == 0) {
60 return plug_closing(ps->plug, NULL, 0, 0);
62 assert(ps->frozen != FROZEN && ps->frozen != THAWING);
63 if (ps->frozen == FREEZING) {
65 * If we've received data while this socket is supposed to
66 * be frozen (because the read winhandl.c started before
67 * sk_set_frozen was called has now returned) then buffer
68 * the data for when we unfreeze.
70 bufchain_add(&ps->inputdata, data, len);
74 * And return a very large backlog, to prevent further
75 * data arriving from winhandl until we unfreeze.
79 return plug_receive(ps->plug, 0, data, len);
84 static int handle_stderr(struct handle *h, void *data, int len)
86 Handle_Socket ps = (Handle_Socket) handle_get_privdata(h);
89 log_proxy_stderr(ps->plug, &ps->stderrdata, data, len);
94 static void handle_sentdata(struct handle *h, int new_backlog)
96 Handle_Socket ps = (Handle_Socket) handle_get_privdata(h);
98 plug_sent(ps->plug, new_backlog);
101 static Plug sk_handle_plug(Socket s, Plug p)
103 Handle_Socket ps = (Handle_Socket) s;
110 static void sk_handle_close(Socket s)
112 Handle_Socket ps = (Handle_Socket) s;
114 if (ps->defer_close) {
115 ps->deferred_close = TRUE;
119 handle_free(ps->send_h);
120 handle_free(ps->recv_h);
121 CloseHandle(ps->send_H);
122 if (ps->recv_H != ps->send_H)
123 CloseHandle(ps->recv_H);
124 bufchain_clear(&ps->inputdata);
125 bufchain_clear(&ps->stderrdata);
130 static int sk_handle_write(Socket s, const char *data, int len)
132 Handle_Socket ps = (Handle_Socket) s;
134 return handle_write(ps->send_h, data, len);
137 static int sk_handle_write_oob(Socket s, const char *data, int len)
140 * oob data is treated as inband; nasty, but nothing really
143 return sk_handle_write(s, data, len);
146 static void sk_handle_write_eof(Socket s)
148 Handle_Socket ps = (Handle_Socket) s;
150 handle_write_eof(ps->send_h);
153 static void sk_handle_flush(Socket s)
155 /* Handle_Socket ps = (Handle_Socket) s; */
159 static void handle_socket_unfreeze(void *psv)
161 Handle_Socket ps = (Handle_Socket) psv;
163 int len, new_backlog;
166 * If we've been put into a state other than THAWING since the
167 * last callback, then we're done.
169 if (ps->frozen != THAWING)
173 * Get some of the data we've buffered.
175 bufchain_prefix(&ps->inputdata, &data, &len);
179 * Hand it off to the plug. Be careful of re-entrance - that might
180 * have the effect of trying to close this socket.
182 ps->defer_close = TRUE;
183 new_backlog = plug_receive(ps->plug, 0, data, len);
184 bufchain_consume(&ps->inputdata, len);
185 ps->defer_close = FALSE;
186 if (ps->deferred_close) {
191 if (bufchain_size(&ps->inputdata) > 0) {
193 * If there's still data in our buffer, stay in THAWING state,
194 * and reschedule ourself.
196 queue_toplevel_callback(handle_socket_unfreeze, ps);
199 * Otherwise, we've successfully thawed!
201 ps->frozen = UNFROZEN;
202 handle_unthrottle(ps->recv_h, new_backlog);
206 static void sk_handle_set_frozen(Socket s, int is_frozen)
208 Handle_Socket ps = (Handle_Socket) s;
211 switch (ps->frozen) {
214 return; /* nothing to do */
218 * We were in the middle of emptying our bufchain, and got
219 * frozen again. In that case, winhandl.c is already
220 * throttled, so just return to FROZEN state. The toplevel
221 * callback will notice and disable itself.
228 * The normal case. Go to FREEZING, and expect one more
229 * load of data from winhandl if we're unlucky.
231 ps->frozen = FREEZING;
235 switch (ps->frozen) {
238 return; /* nothing to do */
242 * If winhandl didn't send us any data throughout the time
243 * we were frozen, then we'll still be in this state and
244 * can just unfreeze in the trivial way.
246 assert(bufchain_size(&ps->inputdata) == 0);
247 ps->frozen = UNFROZEN;
252 * If we have buffered data, go to THAWING and start
253 * releasing it in top-level callbacks.
255 ps->frozen = THAWING;
256 queue_toplevel_callback(handle_socket_unfreeze, ps);
261 static const char *sk_handle_socket_error(Socket s)
263 Handle_Socket ps = (Handle_Socket) s;
267 static char *sk_handle_peer_info(Socket s)
269 Handle_Socket ps = (Handle_Socket) s;
271 static HMODULE kernel32_module;
272 DECL_WINDOWS_FUNCTION(static, BOOL, GetNamedPipeClientProcessId,
275 if (!kernel32_module) {
276 kernel32_module = load_system32_dll("kernel32.dll");
277 GET_WINDOWS_FUNCTION(kernel32_module, GetNamedPipeClientProcessId);
281 * Of course, not all handles managed by this module will be
282 * server ends of named pipes, but if they are, then it's useful
283 * to log what we can find out about the client end.
285 if (p_GetNamedPipeClientProcessId &&
286 p_GetNamedPipeClientProcessId(ps->send_H, &pid))
287 return dupprintf("process id %lu", (unsigned long)pid);
292 Socket make_handle_socket(HANDLE send_H, HANDLE recv_H, HANDLE stderr_H,
293 Plug plug, int overlapped)
295 static const struct socket_function_table socket_fn_table = {
302 sk_handle_set_frozen,
303 sk_handle_socket_error,
308 int flags = (overlapped ? HANDLE_FLAG_OVERLAPPED : 0);
310 ret = snew(struct Socket_handle_tag);
311 ret->fn = &socket_fn_table;
314 ret->frozen = UNFROZEN;
315 bufchain_init(&ret->inputdata);
316 bufchain_init(&ret->stderrdata);
318 ret->recv_H = recv_H;
319 ret->recv_h = handle_input_new(ret->recv_H, handle_gotdata, ret, flags);
320 ret->send_H = send_H;
321 ret->send_h = handle_output_new(ret->send_H, handle_sentdata, ret, flags);
322 ret->stderr_H = stderr_H;
324 ret->stderr_h = handle_input_new(ret->stderr_H, handle_stderr,
327 ret->defer_close = ret->deferred_close = FALSE;