34292b1d |
1 | /* |
2 | * winhandl.c: Module to give Windows front ends the general |
3 | * ability to deal with consoles, pipes, serial ports, or any other |
4 | * type of data stream accessed through a Windows API HANDLE rather |
5 | * than a WinSock SOCKET. |
6 | * |
7 | * We do this by spawning a subthread to continuously try to read |
8 | * from the handle. Every time a read successfully returns some |
9 | * data, the subthread sets an event object which is picked up by |
10 | * the main thread, and the main thread then sets an event in |
11 | * return to instruct the subthread to resume reading. |
12 | * |
13 | * Output works precisely the other way round, in a second |
14 | * subthread. The output subthread should not be attempting to |
15 | * write all the time, because it hasn't always got data _to_ |
16 | * write; so the output thread waits for an event object notifying |
17 | * it to _attempt_ a write, and then it sets an event in return |
18 | * when one completes. |
8e32bfe0 |
19 | * |
20 | * (It's terribly annoying having to spawn a subthread for each |
21 | * direction of each handle. Technically it isn't necessary for |
22 | * serial ports, since we could use overlapped I/O within the main |
23 | * thread and wait directly on the event objects in the OVERLAPPED |
24 | * structures. However, we can't use this trick for some types of |
25 | * file handle at all - for some reason Windows restricts use of |
26 | * OVERLAPPED to files which were opened with the overlapped flag - |
27 | * and so we must use threads for those. This being the case, it's |
28 | * simplest just to use threads for everything rather than trying |
29 | * to keep track of multiple completely separate mechanisms.) |
34292b1d |
30 | */ |
31 | |
34292b1d |
32 | #include <assert.h> |
33 | |
34 | #include "putty.h" |
35 | |
36 | /* ---------------------------------------------------------------------- |
37 | * Generic definitions. |
38 | */ |
39 | |
40 | /* |
41 | * Maximum amount of backlog we will allow to build up on an input |
42 | * handle before we stop reading from it. |
43 | */ |
44 | #define MAX_BACKLOG 32768 |
45 | |
46 | struct handle_generic { |
47 | /* |
48 | * Initial fields common to both handle_input and handle_output |
49 | * structures. |
50 | * |
51 | * The three HANDLEs are set up at initialisation time and are |
52 | * thereafter read-only to both main thread and subthread. |
53 | * `moribund' is only used by the main thread; `done' is |
54 | * written by the main thread before signalling to the |
55 | * subthread. `defunct' and `busy' are used only by the main |
56 | * thread. |
57 | */ |
58 | HANDLE h; /* the handle itself */ |
59 | HANDLE ev_to_main; /* event used to signal main thread */ |
60 | HANDLE ev_from_main; /* event used to signal back to us */ |
61 | int moribund; /* are we going to kill this soon? */ |
62 | int done; /* request subthread to terminate */ |
63 | int defunct; /* has the subthread already gone? */ |
64 | int busy; /* operation currently in progress? */ |
0e03ceff |
65 | void *privdata; /* for client to remember who they are */ |
34292b1d |
66 | }; |
67 | |
68 | /* ---------------------------------------------------------------------- |
69 | * Input threads. |
70 | */ |
71 | |
72 | /* |
73 | * Data required by an input thread. |
74 | */ |
75 | struct handle_input { |
76 | /* |
77 | * Copy of the handle_generic structure. |
78 | */ |
79 | HANDLE h; /* the handle itself */ |
80 | HANDLE ev_to_main; /* event used to signal main thread */ |
81 | HANDLE ev_from_main; /* event used to signal back to us */ |
82 | int moribund; /* are we going to kill this soon? */ |
83 | int done; /* request subthread to terminate */ |
84 | int defunct; /* has the subthread already gone? */ |
85 | int busy; /* operation currently in progress? */ |
0e03ceff |
86 | void *privdata; /* for client to remember who they are */ |
34292b1d |
87 | |
88 | /* |
bdebd7e9 |
89 | * Data set at initialisation and then read-only. |
90 | */ |
91 | int flags; |
92 | |
93 | /* |
34292b1d |
94 | * Data set by the input thread before signalling ev_to_main, |
95 | * and read by the main thread after receiving that signal. |
96 | */ |
97 | char buffer[4096]; /* the data read from the handle */ |
98 | DWORD len; /* how much data that was */ |
21ae394f |
99 | int readerr; /* lets us know about read errors */ |
34292b1d |
100 | |
101 | /* |
102 | * Callback function called by this module when data arrives on |
103 | * an input handle. |
104 | */ |
105 | handle_inputfn_t gotdata; |
106 | }; |
107 | |
108 | /* |
109 | * The actual thread procedure for an input thread. |
110 | */ |
111 | static DWORD WINAPI handle_input_threadfunc(void *param) |
112 | { |
113 | struct handle_input *ctx = (struct handle_input *) param; |
bdebd7e9 |
114 | OVERLAPPED ovl, *povl; |
758a1377 |
115 | HANDLE oev; |
21ae394f |
116 | int readret, readlen; |
bdebd7e9 |
117 | |
758a1377 |
118 | if (ctx->flags & HANDLE_FLAG_OVERLAPPED) { |
bdebd7e9 |
119 | povl = &ovl; |
758a1377 |
120 | oev = CreateEvent(NULL, TRUE, FALSE, NULL); |
121 | } else { |
bdebd7e9 |
122 | povl = NULL; |
758a1377 |
123 | } |
34292b1d |
124 | |
c606abbc |
125 | if (ctx->flags & HANDLE_FLAG_UNITBUFFER) |
126 | readlen = 1; |
127 | else |
128 | readlen = sizeof(ctx->buffer); |
129 | |
34292b1d |
130 | while (1) { |
758a1377 |
131 | if (povl) { |
bdebd7e9 |
132 | memset(povl, 0, sizeof(OVERLAPPED)); |
758a1377 |
133 | povl->hEvent = oev; |
134 | } |
21ae394f |
135 | readret = ReadFile(ctx->h, ctx->buffer,readlen, &ctx->len, povl); |
136 | if (!readret) |
137 | ctx->readerr = GetLastError(); |
138 | else |
139 | ctx->readerr = 0; |
140 | if (povl && !readret && ctx->readerr == ERROR_IO_PENDING) { |
758a1377 |
141 | WaitForSingleObject(povl->hEvent, INFINITE); |
21ae394f |
142 | readret = GetOverlappedResult(ctx->h, povl, &ctx->len, FALSE); |
143 | if (!readret) |
144 | ctx->readerr = GetLastError(); |
145 | else |
146 | ctx->readerr = 0; |
758a1377 |
147 | } |
bdebd7e9 |
148 | |
21ae394f |
149 | if (!readret) { |
425f5af2 |
150 | /* |
151 | * Windows apparently sends ERROR_BROKEN_PIPE when a |
152 | * pipe we're reading from is closed normally from the |
153 | * writing end. This is ludicrous; if that situation |
154 | * isn't a natural EOF, _nothing_ is. So if we get that |
155 | * particular error, we pretend it's EOF. |
156 | */ |
21ae394f |
157 | if (ctx->readerr == ERROR_BROKEN_PIPE) |
158 | ctx->readerr = 0; |
34292b1d |
159 | ctx->len = 0; |
425f5af2 |
160 | } |
34292b1d |
161 | |
21ae394f |
162 | if (readret && ctx->len == 0 && |
bdebd7e9 |
163 | (ctx->flags & HANDLE_FLAG_IGNOREEOF)) |
164 | continue; |
165 | |
34292b1d |
166 | SetEvent(ctx->ev_to_main); |
167 | |
168 | if (!ctx->len) |
169 | break; |
170 | |
171 | WaitForSingleObject(ctx->ev_from_main, INFINITE); |
172 | if (ctx->done) |
173 | break; /* main thread told us to shut down */ |
174 | } |
175 | |
758a1377 |
176 | if (povl) |
177 | CloseHandle(oev); |
178 | |
34292b1d |
179 | return 0; |
180 | } |
181 | |
182 | /* |
183 | * This is called after a succcessful read, or from the |
184 | * `unthrottle' function. It decides whether or not to begin a new |
185 | * read operation. |
186 | */ |
187 | static void handle_throttle(struct handle_input *ctx, int backlog) |
188 | { |
50ab783a |
189 | if (ctx->defunct) |
190 | return; |
34292b1d |
191 | |
192 | /* |
193 | * If there's a read operation already in progress, do nothing: |
194 | * when that completes, we'll come back here and be in a |
195 | * position to make a better decision. |
196 | */ |
197 | if (ctx->busy) |
198 | return; |
199 | |
200 | /* |
201 | * Otherwise, we must decide whether to start a new read based |
202 | * on the size of the backlog. |
203 | */ |
204 | if (backlog < MAX_BACKLOG) { |
205 | SetEvent(ctx->ev_from_main); |
206 | ctx->busy = TRUE; |
207 | } |
208 | } |
209 | |
210 | /* ---------------------------------------------------------------------- |
211 | * Output threads. |
212 | */ |
213 | |
214 | /* |
215 | * Data required by an output thread. |
216 | */ |
217 | struct handle_output { |
218 | /* |
219 | * Copy of the handle_generic structure. |
220 | */ |
221 | HANDLE h; /* the handle itself */ |
222 | HANDLE ev_to_main; /* event used to signal main thread */ |
223 | HANDLE ev_from_main; /* event used to signal back to us */ |
224 | int moribund; /* are we going to kill this soon? */ |
225 | int done; /* request subthread to terminate */ |
226 | int defunct; /* has the subthread already gone? */ |
227 | int busy; /* operation currently in progress? */ |
0e03ceff |
228 | void *privdata; /* for client to remember who they are */ |
34292b1d |
229 | |
230 | /* |
bdebd7e9 |
231 | * Data set at initialisation and then read-only. |
232 | */ |
233 | int flags; |
234 | |
235 | /* |
34292b1d |
236 | * Data set by the main thread before signalling ev_from_main, |
237 | * and read by the input thread after receiving that signal. |
238 | */ |
239 | char *buffer; /* the data to write */ |
240 | DWORD len; /* how much data there is */ |
241 | |
242 | /* |
243 | * Data set by the input thread before signalling ev_to_main, |
244 | * and read by the main thread after receiving that signal. |
245 | */ |
246 | DWORD lenwritten; /* how much data we actually wrote */ |
21ae394f |
247 | int writeerr; /* return value from WriteFile */ |
34292b1d |
248 | |
249 | /* |
250 | * Data only ever read or written by the main thread. |
251 | */ |
252 | bufchain queued_data; /* data still waiting to be written */ |
253 | |
254 | /* |
255 | * Callback function called when the backlog in the bufchain |
256 | * drops. |
257 | */ |
258 | handle_outputfn_t sentdata; |
259 | }; |
260 | |
261 | static DWORD WINAPI handle_output_threadfunc(void *param) |
262 | { |
263 | struct handle_output *ctx = (struct handle_output *) param; |
bdebd7e9 |
264 | OVERLAPPED ovl, *povl; |
21ae394f |
265 | int writeret; |
bdebd7e9 |
266 | |
267 | if (ctx->flags & HANDLE_FLAG_OVERLAPPED) |
268 | povl = &ovl; |
269 | else |
270 | povl = NULL; |
34292b1d |
271 | |
272 | while (1) { |
273 | WaitForSingleObject(ctx->ev_from_main, INFINITE); |
274 | if (ctx->done) { |
275 | SetEvent(ctx->ev_to_main); |
276 | break; |
277 | } |
bdebd7e9 |
278 | if (povl) |
279 | memset(povl, 0, sizeof(OVERLAPPED)); |
21ae394f |
280 | writeret = WriteFile(ctx->h, ctx->buffer, ctx->len, |
281 | &ctx->lenwritten, povl); |
282 | if (!writeret) |
283 | ctx->writeerr = GetLastError(); |
284 | else |
285 | ctx->writeerr = 0; |
286 | if (povl && !writeret && GetLastError() == ERROR_IO_PENDING) { |
287 | writeret = GetOverlappedResult(ctx->h, povl, |
288 | &ctx->lenwritten, TRUE); |
289 | if (!writeret) |
290 | ctx->writeerr = GetLastError(); |
291 | else |
292 | ctx->writeerr = 0; |
293 | } |
bdebd7e9 |
294 | |
34292b1d |
295 | SetEvent(ctx->ev_to_main); |
21ae394f |
296 | if (!writeret) |
34292b1d |
297 | break; |
298 | } |
299 | |
300 | return 0; |
301 | } |
302 | |
303 | static void handle_try_output(struct handle_output *ctx) |
304 | { |
305 | void *senddata; |
306 | int sendlen; |
307 | |
308 | if (!ctx->busy && bufchain_size(&ctx->queued_data)) { |
309 | bufchain_prefix(&ctx->queued_data, &senddata, &sendlen); |
310 | ctx->buffer = senddata; |
311 | ctx->len = sendlen; |
312 | SetEvent(ctx->ev_from_main); |
313 | ctx->busy = TRUE; |
314 | } |
315 | } |
316 | |
317 | /* ---------------------------------------------------------------------- |
318 | * Unified code handling both input and output threads. |
319 | */ |
320 | |
321 | struct handle { |
322 | int output; |
323 | union { |
324 | struct handle_generic g; |
325 | struct handle_input i; |
326 | struct handle_output o; |
327 | } u; |
328 | }; |
329 | |
330 | static tree234 *handles_by_evtomain; |
331 | |
332 | static int handle_cmp_evtomain(void *av, void *bv) |
333 | { |
334 | struct handle *a = (struct handle *)av; |
335 | struct handle *b = (struct handle *)bv; |
336 | |
337 | if ((unsigned)a->u.g.ev_to_main < (unsigned)b->u.g.ev_to_main) |
338 | return -1; |
339 | else if ((unsigned)a->u.g.ev_to_main > (unsigned)b->u.g.ev_to_main) |
340 | return +1; |
341 | else |
342 | return 0; |
343 | } |
344 | |
345 | static int handle_find_evtomain(void *av, void *bv) |
346 | { |
347 | HANDLE *a = (HANDLE *)av; |
348 | struct handle *b = (struct handle *)bv; |
349 | |
350 | if ((unsigned)*a < (unsigned)b->u.g.ev_to_main) |
351 | return -1; |
352 | else if ((unsigned)*a > (unsigned)b->u.g.ev_to_main) |
353 | return +1; |
354 | else |
355 | return 0; |
356 | } |
357 | |
0e03ceff |
358 | struct handle *handle_input_new(HANDLE handle, handle_inputfn_t gotdata, |
bdebd7e9 |
359 | void *privdata, int flags) |
34292b1d |
360 | { |
361 | struct handle *h = snew(struct handle); |
600f6499 |
362 | DWORD in_threadid; /* required for Win9x */ |
34292b1d |
363 | |
364 | h->output = FALSE; |
365 | h->u.i.h = handle; |
366 | h->u.i.ev_to_main = CreateEvent(NULL, FALSE, FALSE, NULL); |
367 | h->u.i.ev_from_main = CreateEvent(NULL, FALSE, FALSE, NULL); |
368 | h->u.i.gotdata = gotdata; |
34292b1d |
369 | h->u.i.defunct = FALSE; |
370 | h->u.i.moribund = FALSE; |
371 | h->u.i.done = FALSE; |
0e03ceff |
372 | h->u.i.privdata = privdata; |
bdebd7e9 |
373 | h->u.i.flags = flags; |
34292b1d |
374 | |
375 | if (!handles_by_evtomain) |
376 | handles_by_evtomain = newtree234(handle_cmp_evtomain); |
377 | add234(handles_by_evtomain, h); |
378 | |
379 | CreateThread(NULL, 0, handle_input_threadfunc, |
600f6499 |
380 | &h->u.i, 0, &in_threadid); |
2ceabd36 |
381 | h->u.i.busy = TRUE; |
34292b1d |
382 | |
383 | return h; |
384 | } |
385 | |
0e03ceff |
386 | struct handle *handle_output_new(HANDLE handle, handle_outputfn_t sentdata, |
bdebd7e9 |
387 | void *privdata, int flags) |
34292b1d |
388 | { |
389 | struct handle *h = snew(struct handle); |
600f6499 |
390 | DWORD out_threadid; /* required for Win9x */ |
34292b1d |
391 | |
392 | h->output = TRUE; |
393 | h->u.o.h = handle; |
394 | h->u.o.ev_to_main = CreateEvent(NULL, FALSE, FALSE, NULL); |
395 | h->u.o.ev_from_main = CreateEvent(NULL, FALSE, FALSE, NULL); |
396 | h->u.o.busy = FALSE; |
397 | h->u.o.defunct = FALSE; |
398 | h->u.o.moribund = FALSE; |
399 | h->u.o.done = FALSE; |
0e03ceff |
400 | h->u.o.privdata = privdata; |
34292b1d |
401 | bufchain_init(&h->u.o.queued_data); |
402 | h->u.o.sentdata = sentdata; |
bdebd7e9 |
403 | h->u.o.flags = flags; |
34292b1d |
404 | |
405 | if (!handles_by_evtomain) |
406 | handles_by_evtomain = newtree234(handle_cmp_evtomain); |
407 | add234(handles_by_evtomain, h); |
408 | |
409 | CreateThread(NULL, 0, handle_output_threadfunc, |
600f6499 |
410 | &h->u.i, 0, &out_threadid); |
34292b1d |
411 | |
412 | return h; |
413 | } |
414 | |
415 | int handle_write(struct handle *h, const void *data, int len) |
416 | { |
417 | assert(h->output); |
418 | bufchain_add(&h->u.o.queued_data, data, len); |
419 | handle_try_output(&h->u.o); |
420 | return bufchain_size(&h->u.o.queued_data); |
421 | } |
422 | |
423 | HANDLE *handle_get_events(int *nevents) |
424 | { |
425 | HANDLE *ret; |
426 | struct handle *h; |
427 | int i, n, size; |
428 | |
429 | /* |
430 | * Go through our tree counting the handle objects currently |
431 | * engaged in useful activity. |
432 | */ |
433 | ret = NULL; |
434 | n = size = 0; |
435 | if (handles_by_evtomain) { |
436 | for (i = 0; (h = index234(handles_by_evtomain, i)) != NULL; i++) { |
437 | if (h->u.g.busy) { |
438 | if (n >= size) { |
439 | size += 32; |
440 | ret = sresize(ret, size, HANDLE); |
441 | } |
442 | ret[n++] = h->u.g.ev_to_main; |
443 | } |
444 | } |
445 | } |
446 | |
447 | *nevents = n; |
448 | return ret; |
449 | } |
450 | |
451 | static void handle_destroy(struct handle *h) |
452 | { |
453 | if (h->output) |
454 | bufchain_clear(&h->u.o.queued_data); |
455 | CloseHandle(h->u.g.ev_from_main); |
456 | CloseHandle(h->u.g.ev_to_main); |
457 | del234(handles_by_evtomain, h); |
458 | sfree(h); |
459 | } |
460 | |
461 | void handle_free(struct handle *h) |
462 | { |
463 | /* |
464 | * If the handle is currently busy, we cannot immediately free |
465 | * it. Instead we must wait until it's finished its current |
466 | * operation, because otherwise the subthread will write to |
467 | * invalid memory after we free its context from under it. |
468 | */ |
469 | assert(h && !h->u.g.moribund); |
470 | if (h->u.g.busy) { |
471 | /* |
472 | * Just set the moribund flag, which will be noticed next |
473 | * time an operation completes. |
474 | */ |
475 | h->u.g.moribund = TRUE; |
476 | } else if (h->u.g.defunct) { |
477 | /* |
478 | * There isn't even a subthread; we can go straight to |
479 | * handle_destroy. |
480 | */ |
481 | handle_destroy(h); |
482 | } else { |
483 | /* |
484 | * The subthread is alive but not busy, so we now signal it |
485 | * to die. Set the moribund flag to indicate that it will |
486 | * want destroying after that. |
487 | */ |
488 | h->u.g.moribund = TRUE; |
489 | h->u.g.done = TRUE; |
c969e831 |
490 | h->u.g.busy = TRUE; |
34292b1d |
491 | SetEvent(h->u.g.ev_from_main); |
492 | } |
493 | } |
494 | |
495 | void handle_got_event(HANDLE event) |
496 | { |
497 | struct handle *h; |
498 | |
499 | assert(handles_by_evtomain); |
500 | h = find234(handles_by_evtomain, &event, handle_find_evtomain); |
501 | if (!h) { |
502 | /* |
503 | * This isn't an error condition. If two or more event |
504 | * objects were signalled during the same select operation, |
505 | * and processing of the first caused the second handle to |
506 | * be closed, then it will sometimes happen that we receive |
507 | * an event notification here for a handle which is already |
508 | * deceased. In that situation we simply do nothing. |
509 | */ |
510 | return; |
511 | } |
512 | |
513 | if (h->u.g.moribund) { |
514 | /* |
515 | * A moribund handle is already treated as dead from the |
516 | * external user's point of view, so do nothing with the |
517 | * actual event. Just signal the thread to die if |
518 | * necessary, or destroy the handle if not. |
519 | */ |
520 | if (h->u.g.done) { |
521 | handle_destroy(h); |
522 | } else { |
523 | h->u.g.done = TRUE; |
c969e831 |
524 | h->u.g.busy = TRUE; |
34292b1d |
525 | SetEvent(h->u.g.ev_from_main); |
526 | } |
527 | return; |
528 | } |
529 | |
530 | if (!h->output) { |
531 | int backlog; |
532 | |
533 | h->u.i.busy = FALSE; |
534 | |
535 | /* |
536 | * A signal on an input handle means data has arrived. |
537 | */ |
538 | if (h->u.i.len == 0) { |
539 | /* |
540 | * EOF, or (nearly equivalently) read error. |
541 | */ |
21ae394f |
542 | h->u.i.gotdata(h, NULL, -h->u.i.readerr); |
34292b1d |
543 | h->u.i.defunct = TRUE; |
544 | } else { |
545 | backlog = h->u.i.gotdata(h, h->u.i.buffer, h->u.i.len); |
546 | handle_throttle(&h->u.i, backlog); |
547 | } |
548 | } else { |
549 | h->u.o.busy = FALSE; |
550 | |
551 | /* |
552 | * A signal on an output handle means we have completed a |
553 | * write. Call the callback to indicate that the output |
554 | * buffer size has decreased, or to indicate an error. |
555 | */ |
21ae394f |
556 | if (h->u.o.writeerr) { |
34292b1d |
557 | /* |
558 | * Write error. Send a negative value to the callback, |
559 | * and mark the thread as defunct (because the output |
560 | * thread is terminating by now). |
561 | */ |
21ae394f |
562 | h->u.o.sentdata(h, -h->u.o.writeerr); |
34292b1d |
563 | h->u.o.defunct = TRUE; |
564 | } else { |
565 | bufchain_consume(&h->u.o.queued_data, h->u.o.lenwritten); |
566 | h->u.o.sentdata(h, bufchain_size(&h->u.o.queued_data)); |
567 | handle_try_output(&h->u.o); |
568 | } |
569 | } |
570 | } |
571 | |
572 | void handle_unthrottle(struct handle *h, int backlog) |
573 | { |
574 | assert(!h->output); |
575 | handle_throttle(&h->u.i, backlog); |
576 | } |
577 | |
578 | int handle_backlog(struct handle *h) |
579 | { |
580 | assert(h->output); |
581 | return bufchain_size(&h->u.o.queued_data); |
582 | } |
0e03ceff |
583 | |
584 | void *handle_get_privdata(struct handle *h) |
585 | { |
586 | return h->u.g.privdata; |
587 | } |