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1 /*
2  * libwebsockets - small server side websockets and web server implementation
3  *
4  * Copyright (C) 2010 - 2021 Andy Green <andy@warmcat.com>
5  *
6  * Permission is hereby granted, free of charge, to any person obtaining a copy
7  * of this software and associated documentation files (the "Software"), to
8  * deal in the Software without restriction, including without limitation the
9  * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
10  * sell copies of the Software, and to permit persons to whom the Software is
11  * furnished to do so, subject to the following conditions:
12  *
13  * The above copyright notice and this permission notice shall be included in
14  * all copies or substantial portions of the Software.
15  *
16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
19  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
21  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
22  * IN THE SOFTWARE.
23  */
24 
25 #include "private-lib-core.h"
26 
27 #if defined(_DEBUG)
28 void
lws_service_assert_loop_thread(struct lws_context * cx,int tsi)29 lws_service_assert_loop_thread(struct lws_context *cx, int tsi)
30 {
31 	if (!cx->event_loop_ops->foreign_thread)
32 		/* we can't judge it */
33 		return;
34 
35 	if (!cx->event_loop_ops->foreign_thread(cx, tsi))
36 		/* OK */
37 		return;
38 
39 	/*
40 	 * Lws apis are NOT THREADSAFE with the sole exception of
41 	 * lws_cancel_service().  If you look at the assert backtrace, you
42 	 * should see you're illegally calling an lws api from another thread.
43 	 */
44 	assert(0);
45 }
46 #endif
47 
48 int
lws_callback_as_writeable(struct lws * wsi)49 lws_callback_as_writeable(struct lws *wsi)
50 {
51 	int n, m;
52 
53 	n = wsi->role_ops->writeable_cb[lwsi_role_server(wsi)];
54 	m = user_callback_handle_rxflow(wsi->a.protocol->callback,
55 					wsi, (enum lws_callback_reasons) n,
56 					wsi->user_space, NULL, 0);
57 
58 	return m;
59 }
60 
61 int
lws_handle_POLLOUT_event(struct lws * wsi,struct lws_pollfd * pollfd)62 lws_handle_POLLOUT_event(struct lws *wsi, struct lws_pollfd *pollfd)
63 {
64 	volatile struct lws *vwsi = (volatile struct lws *)wsi;
65 	int n;
66 
67 	if (wsi->socket_is_permanently_unusable)
68 		return 0;
69 
70 	vwsi->leave_pollout_active = 0;
71 	vwsi->handling_pollout = 1;
72 	/*
73 	 * if another thread wants POLLOUT on us, from here on while
74 	 * handling_pollout is set, he will only set leave_pollout_active.
75 	 * If we are going to disable POLLOUT, we will check that first.
76 	 */
77 	wsi->could_have_pending = 0; /* clear back-to-back write detection */
78 
79 	/*
80 	 * user callback is lowest priority to get these notifications
81 	 * actually, since other pending things cannot be disordered
82 	 *
83 	 * Priority 1: pending truncated sends are incomplete ws fragments
84 	 *	       If anything else sent first the protocol would be
85 	 *	       corrupted.
86 	 *
87 	 *	       These are post- any compression transform
88 	 */
89 
90 	if (lws_has_buffered_out(wsi)) {
91 		if (lws_issue_raw(wsi, NULL, 0) < 0) {
92 			lwsl_wsi_info(wsi, "signalling to close");
93 			goto bail_die;
94 		}
95 		/* leave POLLOUT active either way */
96 		goto bail_ok;
97 	} else
98 		if (lwsi_state(wsi) == LRS_FLUSHING_BEFORE_CLOSE) {
99 			wsi->socket_is_permanently_unusable = 1;
100 			goto bail_die; /* retry closing now */
101 		}
102 
103 	/* Priority 2: pre- compression transform */
104 
105 #if defined(LWS_WITH_HTTP_STREAM_COMPRESSION)
106 	if (wsi->http.comp_ctx.buflist_comp ||
107 	    wsi->http.comp_ctx.may_have_more) {
108 		enum lws_write_protocol wp = LWS_WRITE_HTTP;
109 
110 		lwsl_wsi_info(wsi, "compl comp partial (buflist_comp %p, may %d)",
111 				   wsi->http.comp_ctx.buflist_comp,
112 				   wsi->http.comp_ctx.may_have_more);
113 
114 		if (lws_rops_fidx(wsi->role_ops, LWS_ROPS_write_role_protocol) &&
115 		    lws_rops_func_fidx(wsi->role_ops, LWS_ROPS_write_role_protocol).
116 					write_role_protocol(wsi, NULL, 0, &wp) < 0) {
117 			lwsl_wsi_info(wsi, "signalling to close");
118 			goto bail_die;
119 		}
120 		lws_callback_on_writable(wsi);
121 
122 		goto bail_ok;
123 	}
124 #endif
125 
126 #ifdef LWS_WITH_CGI
127 	/*
128 	 * A cgi connection's wire protocol remains h1 or h2.  He is just
129 	 * getting his data from his child cgis.
130 	 */
131 	if (wsi->http.cgi) {
132 		/* also one shot */
133 		if (pollfd)
134 			if (lws_change_pollfd(wsi, LWS_POLLOUT, 0)) {
135 				lwsl_wsi_info(wsi, "failed at set pollfd");
136 				return 1;
137 			}
138 		goto user_service_go_again;
139 	}
140 #endif
141 
142 	/* if we got here, we should have wire protocol ops set on the wsi */
143 	assert(wsi->role_ops);
144 
145 	if (!lws_rops_fidx(wsi->role_ops, LWS_ROPS_handle_POLLOUT))
146 		goto bail_ok;
147 
148 	n = lws_rops_func_fidx(wsi->role_ops, LWS_ROPS_handle_POLLOUT).
149 							handle_POLLOUT(wsi);
150 	switch (n) {
151 	case LWS_HP_RET_BAIL_OK:
152 		goto bail_ok;
153 	case LWS_HP_RET_BAIL_DIE:
154 		goto bail_die;
155 	case LWS_HP_RET_DROP_POLLOUT:
156 	case LWS_HP_RET_USER_SERVICE:
157 		break;
158 	default:
159 		assert(0);
160 	}
161 
162 	/* one shot */
163 
164 	if (pollfd) {
165 		int eff = vwsi->leave_pollout_active;
166 
167 		if (!eff) {
168 			if (lws_change_pollfd(wsi, LWS_POLLOUT, 0)) {
169 				lwsl_wsi_info(wsi, "failed at set pollfd");
170 				goto bail_die;
171 			}
172 		}
173 
174 		vwsi->handling_pollout = 0;
175 
176 		/* cannot get leave_pollout_active set after the above */
177 		if (!eff && wsi->leave_pollout_active) {
178 			/*
179 			 * got set inbetween sampling eff and clearing
180 			 * handling_pollout, force POLLOUT on
181 			 */
182 			lwsl_wsi_debug(wsi, "leave_pollout_active");
183 			if (lws_change_pollfd(wsi, 0, LWS_POLLOUT)) {
184 				lwsl_wsi_info(wsi, "failed at set pollfd");
185 				goto bail_die;
186 			}
187 		}
188 
189 		vwsi->leave_pollout_active = 0;
190 	}
191 
192 	if (lwsi_role_client(wsi) && !wsi->hdr_parsing_completed &&
193 	     lwsi_state(wsi) != LRS_H2_WAITING_TO_SEND_HEADERS &&
194 	     lwsi_state(wsi) != LRS_ISSUE_HTTP_BODY)
195 		goto bail_ok;
196 
197 	if (n == LWS_HP_RET_DROP_POLLOUT)
198 		goto bail_ok;
199 
200 
201 #ifdef LWS_WITH_CGI
202 user_service_go_again:
203 #endif
204 
205 	if (lws_rops_fidx(wsi->role_ops, LWS_ROPS_perform_user_POLLOUT)) {
206 		if (lws_rops_func_fidx(wsi->role_ops,
207 				       LWS_ROPS_perform_user_POLLOUT).
208 						perform_user_POLLOUT(wsi) == -1)
209 			goto bail_die;
210 		else
211 			goto bail_ok;
212 	}
213 
214 	lwsl_wsi_debug(wsi, "non mux: wsistate 0x%lx, ops %s",
215 			    (unsigned long)wsi->wsistate, wsi->role_ops->name);
216 
217 	vwsi = (volatile struct lws *)wsi;
218 	vwsi->leave_pollout_active = 0;
219 
220 	n = lws_callback_as_writeable(wsi);
221 	vwsi->handling_pollout = 0;
222 
223 	if (vwsi->leave_pollout_active)
224 		if (lws_change_pollfd(wsi, 0, LWS_POLLOUT))
225 			goto bail_die;
226 
227 	return n;
228 
229 	/*
230 	 * since these don't disable the POLLOUT, they are always doing the
231 	 * right thing for leave_pollout_active whether it was set or not.
232 	 */
233 
234 bail_ok:
235 	vwsi->handling_pollout = 0;
236 	vwsi->leave_pollout_active = 0;
237 
238 	return 0;
239 
240 bail_die:
241 	vwsi->handling_pollout = 0;
242 	vwsi->leave_pollout_active = 0;
243 
244 	return -1;
245 }
246 
247 int
lws_rxflow_cache(struct lws * wsi,unsigned char * buf,size_t n,size_t len)248 lws_rxflow_cache(struct lws *wsi, unsigned char *buf, size_t n, size_t len)
249 {
250 	struct lws_context_per_thread *pt = &wsi->a.context->pt[(int)wsi->tsi];
251 	uint8_t *buffered;
252 	size_t blen;
253 	int ret = LWSRXFC_CACHED, m;
254 
255 	/* his RX is flowcontrolled, don't send remaining now */
256 	blen = lws_buflist_next_segment_len(&wsi->buflist, &buffered);
257 	if (blen) {
258 		if (buf >= buffered && buf + len <= buffered + blen &&
259 		    blen != (size_t)len) {
260 			/*
261 			 * rxflow while we were spilling prev rxflow
262 			 *
263 			 * len indicates how much was unused, then... so trim
264 			 * the head buflist to match that situation
265 			 */
266 
267 			lws_buflist_use_segment(&wsi->buflist, blen - len);
268 			lwsl_wsi_debug(wsi, "trim existing rxflow %d -> %d",
269 					    (int)blen, (int)len);
270 
271 			return LWSRXFC_TRIMMED;
272 		}
273 		ret = LWSRXFC_ADDITIONAL;
274 	}
275 
276 	/* a new rxflow, buffer it and warn caller */
277 
278 	lwsl_wsi_debug(wsi, "rxflow append %d", (int)(len - n));
279 	m = lws_buflist_append_segment(&wsi->buflist, buf + n, len - n);
280 
281 	if (m < 0)
282 		return LWSRXFC_ERROR;
283 	if (m) {
284 		lwsl_wsi_debug(wsi, "added to rxflow list");;
285 		if (lws_dll2_is_detached(&wsi->dll_buflist))
286 			lws_dll2_add_head(&wsi->dll_buflist, &pt->dll_buflist_owner);
287 	}
288 
289 	return ret;
290 }
291 
292 /* this is used by the platform service code to stop us waiting for network
293  * activity in poll() when we have something that already needs service
294  */
295 
296 int
lws_service_adjust_timeout(struct lws_context * context,int timeout_ms,int tsi)297 lws_service_adjust_timeout(struct lws_context *context, int timeout_ms, int tsi)
298 {
299 	struct lws_context_per_thread *pt;
300 
301 	if (!context)
302 		return 1;
303 
304         if (!context->protocol_init_done)
305                 if (lws_protocol_init(context))
306                         return 1;
307 
308 #if defined(LWS_WITH_SYS_SMD)
309 	if (!tsi && lws_smd_message_pending(context)) {
310 		lws_smd_msg_distribute(context);
311 		if (lws_smd_message_pending(context))
312 			return 0;
313 	}
314 #endif
315 
316 	pt = &context->pt[tsi];
317 
318 	if (pt->evlib_pt) {
319 		lws_usec_t u;
320 
321 		lws_pt_lock(pt, __func__); /* -------------- pt { */
322 
323 		u = __lws_sul_service_ripe(pt->pt_sul_owner,
324 				      LWS_COUNT_PT_SUL_OWNERS, lws_now_usecs());
325 		/*
326 		 * We will come back with 0 if nothing to do at the moment, or
327 		 * the number of us until something to do
328 		 */
329 		if (u && u < (lws_usec_t)timeout_ms * (lws_usec_t)1000)
330 			timeout_ms = (int)(u / 1000);
331 
332 		lws_pt_unlock(pt);
333 	}
334 
335 	/*
336 	 * Figure out if we really want to wait in poll()... we only need to
337 	 * wait if really nothing already to do and we have to wait for
338 	 * something from network
339 	 */
340 #if defined(LWS_ROLE_WS) && !defined(LWS_WITHOUT_EXTENSIONS)
341 	/* 1) if we know we are draining rx ext, do not wait in poll */
342 	if (pt->ws.rx_draining_ext_list)
343 		return 0;
344 #endif
345 
346 #if defined(LWS_WITH_TLS)
347 	/* 2) if we know we have non-network pending data,
348 	 *    do not wait in poll */
349 
350 	if (pt->context->tls_ops &&
351 	    pt->context->tls_ops->fake_POLLIN_for_buffered &&
352 	    pt->context->tls_ops->fake_POLLIN_for_buffered(pt))
353 			return 0;
354 #endif
355 
356 	/*
357 	 * 4) If there is any wsi with rxflow buffered and in a state to process
358 	 *    it, we should not wait in poll
359 	 */
360 
361 	lws_start_foreach_dll(struct lws_dll2 *, d, pt->dll_buflist_owner.head) {
362 		struct lws *wsi = lws_container_of(d, struct lws, dll_buflist);
363 
364 		if (!lws_is_flowcontrolled(wsi) &&
365 		     lwsi_state(wsi) != LRS_DEFERRING_ACTION)
366 			return 0;
367 
368 	/*
369 	 * 5) If any guys with http compression to spill, we shouldn't wait in
370 	 *    poll but hurry along and service them
371 	 */
372 
373 	} lws_end_foreach_dll(d);
374 
375 	return timeout_ms;
376 }
377 
378 /*
379  * POLLIN said there is something... we must read it, and either use it; or
380  * if other material already in the buflist append it and return the buflist
381  * head material.
382  */
383 int
lws_buflist_aware_read(struct lws_context_per_thread * pt,struct lws * wsi,struct lws_tokens * ebuf,char fr,const char * hint)384 lws_buflist_aware_read(struct lws_context_per_thread *pt, struct lws *wsi,
385 		       struct lws_tokens *ebuf, char fr, const char *hint)
386 {
387 	int n, e, bns;
388 	uint8_t *ep, *b;
389 
390 	// lwsl_debug("%s: %s: %s: prior %d\n", __func__, lws_wsi_tag(wsi), hint, prior);
391 	// lws_buflist_describe(&wsi->buflist, wsi, __func__);
392 
393 	(void)hint;
394 	if (!ebuf->token)
395 		ebuf->token = pt->serv_buf + LWS_PRE;
396 	if (!ebuf->len ||
397 	    (unsigned int)ebuf->len > wsi->a.context->pt_serv_buf_size - LWS_PRE)
398 		ebuf->len = (int)(wsi->a.context->pt_serv_buf_size - LWS_PRE);
399 
400 	e = ebuf->len;
401 	ep = ebuf->token;
402 
403 	/* h2 or muxed stream... must force the read due to HOL blocking */
404 
405 	if (wsi->mux_substream)
406 		fr = 1;
407 
408 	/* there's something on the buflist? */
409 
410 	bns = (int)lws_buflist_next_segment_len(&wsi->buflist, &ebuf->token);
411 	b = ebuf->token;
412 
413 	if (!fr && bns)
414 		goto buflist_material;
415 
416 	/* we're going to read something */
417 
418 	ebuf->token = ep;
419 	ebuf->len = n = lws_ssl_capable_read(wsi, ep, (size_t)e);
420 
421 	lwsl_wsi_debug(wsi, "%s: ssl_capable_read %d", hint, ebuf->len);
422 
423 	if (!bns && /* only acknowledge error when we handled buflist content */
424 	    n == LWS_SSL_CAPABLE_ERROR) {
425 		lwsl_debug("%s: SSL_CAPABLE_ERROR\n", __func__);
426 		return -1;
427 	}
428 
429 	if (n <= 0 && bns)
430 		/*
431 		 * There wasn't anything to read yet, but there's something
432 		 * on the buflist to give him
433 		 */
434 		goto buflist_material;
435 
436 	/* we read something */
437 
438 	if (fr && bns) {
439 		/*
440 		 * Stash what we read, since there's earlier buflist material
441 		 */
442 
443 		n = lws_buflist_append_segment(&wsi->buflist, ebuf->token, (size_t)ebuf->len);
444 		if (n < 0)
445 			return -1;
446 		if (n && lws_dll2_is_detached(&wsi->dll_buflist))
447 			lws_dll2_add_head(&wsi->dll_buflist,
448 					  &pt->dll_buflist_owner);
449 
450 		goto buflist_material;
451 	}
452 
453 	/*
454 	 * directly return what we read
455 	 */
456 
457 	return 0;
458 
459 buflist_material:
460 
461 	ebuf->token = b;
462 	if (e < bns)
463 		/* restrict to e, if more than e available */
464 		ebuf->len = e;
465 	else
466 		ebuf->len = bns;
467 
468 	return 1; /* from buflist */
469 }
470 
471 int
lws_buflist_aware_finished_consuming(struct lws * wsi,struct lws_tokens * ebuf,int used,int buffered,const char * hint)472 lws_buflist_aware_finished_consuming(struct lws *wsi, struct lws_tokens *ebuf,
473 				     int used, int buffered, const char *hint)
474 {
475 	struct lws_context_per_thread *pt = &wsi->a.context->pt[(int)wsi->tsi];
476 	int m;
477 
478 	/* it's in the buflist; we didn't use any */
479 
480 	if (!used && buffered)
481 		return 0;
482 
483 	if (used && buffered) {
484 		if (wsi->buflist) {
485 			m = (int)lws_buflist_use_segment(&wsi->buflist,
486 							 (size_t)used);
487 			if (m)
488 				return 0;
489 		}
490 
491 		lwsl_wsi_info(wsi, "removed from dll_buflist");
492 		lws_dll2_remove(&wsi->dll_buflist);
493 
494 		return 0;
495 	}
496 
497 	/* any remainder goes on the buflist */
498 
499 	if (used < ebuf->len && ebuf->len >= 0 && used >= 0) {
500 		m = lws_buflist_append_segment(&wsi->buflist,
501 					       ebuf->token + used,
502 					       (unsigned int)(ebuf->len - used));
503 		if (m < 0)
504 			return 1; /* OOM */
505 		if (m) {
506 			lwsl_wsi_debug(wsi, "added to rxflow list");
507 			if (lws_dll2_is_detached(&wsi->dll_buflist))
508 				lws_dll2_add_head(&wsi->dll_buflist,
509 					 &pt->dll_buflist_owner);
510 		}
511 	}
512 
513 	return 0;
514 }
515 
516 void
lws_service_do_ripe_rxflow(struct lws_context_per_thread * pt)517 lws_service_do_ripe_rxflow(struct lws_context_per_thread *pt)
518 {
519 	struct lws_pollfd pfd;
520 
521 	if (!pt->dll_buflist_owner.head)
522 		return;
523 
524 	/*
525 	 * service all guys with pending rxflow that reached a state they can
526 	 * accept the pending data
527 	 */
528 
529 	lws_pt_lock(pt, __func__);
530 
531 	lws_start_foreach_dll_safe(struct lws_dll2 *, d, d1,
532 				   pt->dll_buflist_owner.head) {
533 		struct lws *wsi = lws_container_of(d, struct lws, dll_buflist);
534 
535 		pfd.events = LWS_POLLIN;
536 		pfd.revents = LWS_POLLIN;
537 		pfd.fd = -1;
538 
539 		lwsl_wsi_debug(wsi, "rxflow processing: fc=%d, 0x%lx",
540 				    lws_is_flowcontrolled(wsi),
541 				    (unsigned long)wsi->wsistate);
542 
543 		if (!lws_is_flowcontrolled(wsi) &&
544 		    lwsi_state(wsi) != LRS_DEFERRING_ACTION) {
545 			pt->inside_lws_service = 1;
546 
547 			if (lws_rops_func_fidx(wsi->role_ops,
548 					       LWS_ROPS_handle_POLLIN).
549 						handle_POLLIN(pt, wsi, &pfd) ==
550 						   LWS_HPI_RET_PLEASE_CLOSE_ME)
551 				lws_close_free_wsi(wsi, LWS_CLOSE_STATUS_NOSTATUS,
552 						"close_and_handled");
553 			pt->inside_lws_service = 0;
554 		}
555 
556 	} lws_end_foreach_dll_safe(d, d1);
557 
558 	lws_pt_unlock(pt);
559 }
560 
561 /*
562  * guys that need POLLIN service again without waiting for network action
563  * can force POLLIN here if not flowcontrolled, so they will get service.
564  *
565  * Return nonzero if anybody got their POLLIN faked
566  */
567 int
lws_service_flag_pending(struct lws_context * context,int tsi)568 lws_service_flag_pending(struct lws_context *context, int tsi)
569 {
570 	struct lws_context_per_thread *pt;
571 	int forced = 0;
572 
573 	if (!context)
574 		return 1;
575 
576 	pt = &context->pt[tsi];
577 
578 	lws_pt_lock(pt, __func__);
579 
580 	/*
581 	 * 1) If there is any wsi with a buflist and in a state to process
582 	 *    it, we should not wait in poll
583 	 */
584 
585 	lws_start_foreach_dll(struct lws_dll2 *, d, pt->dll_buflist_owner.head) {
586 		struct lws *wsi = lws_container_of(d, struct lws, dll_buflist);
587 
588 		if (!lws_is_flowcontrolled(wsi) &&
589 		     lwsi_state(wsi) != LRS_DEFERRING_ACTION) {
590 			forced = 1;
591 			break;
592 		}
593 	} lws_end_foreach_dll(d);
594 
595 #if defined(LWS_ROLE_WS)
596 	forced |= lws_rops_func_fidx(&role_ops_ws,
597 				     LWS_ROPS_service_flag_pending).
598 					service_flag_pending(context, tsi);
599 #endif
600 
601 #if defined(LWS_WITH_TLS)
602 	/*
603 	 * 2) For all guys with buffered SSL read data already saved up, if they
604 	 * are not flowcontrolled, fake their POLLIN status so they'll get
605 	 * service to use up the buffered incoming data, even though their
606 	 * network socket may have nothing
607 	 */
608 	lws_start_foreach_dll_safe(struct lws_dll2 *, p, p1,
609 			lws_dll2_get_head(&pt->tls.dll_pending_tls_owner)) {
610 		struct lws *wsi = lws_container_of(p, struct lws,
611 						   tls.dll_pending_tls);
612 
613 		if (wsi->position_in_fds_table >= 0) {
614 
615 			pt->fds[wsi->position_in_fds_table].revents = (short)(
616 					pt->fds[wsi->position_in_fds_table].revents |
617 				(pt->fds[wsi->position_in_fds_table].events &
618 								LWS_POLLIN));
619 			if (pt->fds[wsi->position_in_fds_table].revents &
620 								LWS_POLLIN)
621 				/*
622 				 * We're not going to remove the wsi from the
623 				 * pending tls list.  The processing will have
624 				 * to do it if he exhausts the pending tls.
625 				 */
626 				forced = 1;
627 		}
628 
629 	} lws_end_foreach_dll_safe(p, p1);
630 #endif
631 
632 	lws_pt_unlock(pt);
633 
634 	return forced;
635 }
636 
637 int
lws_service_fd_tsi(struct lws_context * context,struct lws_pollfd * pollfd,int tsi)638 lws_service_fd_tsi(struct lws_context *context, struct lws_pollfd *pollfd,
639 		   int tsi)
640 {
641 	struct lws_context_per_thread *pt;
642 	struct lws *wsi;
643 	char cow = 0;
644 
645 	if (!context || context->service_no_longer_possible)
646 		return -1;
647 
648 	pt = &context->pt[tsi];
649 
650 	if (pt->event_loop_pt_unused)
651 		return -1;
652 
653 	if (!pollfd) {
654 		/*
655 		 * calling with NULL pollfd for periodic background processing
656 		 * is no longer needed and is now illegal.
657 		 */
658 		assert(pollfd);
659 		return -1;
660 	}
661 	assert(lws_socket_is_valid(pollfd->fd));
662 
663 	/* no, here to service a socket descriptor */
664 	wsi = wsi_from_fd(context, pollfd->fd);
665 	if (!wsi)
666 		/* not lws connection ... leave revents alone and return */
667 		return 0;
668 
669 #if LWS_MAX_SMP > 1
670 	if (wsi->undergoing_init_from_other_pt)
671 		/*
672 		 * Temporary situation that other service thread is initializing
673 		 * this wsi right now for use on our service thread.
674 		 */
675 		return 0;
676 #endif
677 
678 	/*
679 	 * so that caller can tell we handled, past here we need to
680 	 * zero down pollfd->revents after handling
681 	 */
682 
683 	/*
684 	 * Whatever the situation with buffered rx packets, or explicitly read-
685 	 * and-buffered rx going to be handled before we want to acknowledge the
686 	 * socket is gone, any sign of HUP always immediately means no more tx
687 	 * is possible.
688 	 */
689 
690 	if ((pollfd->revents & LWS_POLLHUP) == LWS_POLLHUP) {
691 		wsi->socket_is_permanently_unusable = 1;
692 
693 		if (!(pollfd->revents & pollfd->events & LWS_POLLIN)) {
694 
695 			/* ... there are no pending rx packets waiting... */
696 
697 			if (!lws_buflist_total_len(&wsi->buflist)) {
698 
699 				/*
700 				 * ... nothing stashed in the buflist either,
701 				 * so acknowledge the wsi is done
702 				 */
703 
704 				lwsl_wsi_debug(wsi, "Session Socket %d dead",
705 						    pollfd->fd);
706 
707 				goto close_and_handled;
708 			}
709 
710 			/*
711 			 * ... in fact we have some unread rx buffered in the
712 			 * input buflist.  Hold off the closing a bit...
713 			 */
714 
715 			lws_set_timeout(wsi, PENDING_TIMEOUT_CLOSE_ACK, 3);
716 		}
717 	}
718 
719 #ifdef _WIN32
720 	if (pollfd->revents & LWS_POLLOUT)
721 		wsi->sock_send_blocking = FALSE;
722 #endif
723 
724 #if defined(LWS_WITH_TLS)
725 	if (lwsi_state(wsi) == LRS_SHUTDOWN &&
726 	    lws_is_ssl(wsi) && wsi->tls.ssl) {
727 		switch (__lws_tls_shutdown(wsi)) {
728 		case LWS_SSL_CAPABLE_DONE:
729 		case LWS_SSL_CAPABLE_ERROR:
730 			goto close_and_handled;
731 
732 		case LWS_SSL_CAPABLE_MORE_SERVICE_READ:
733 		case LWS_SSL_CAPABLE_MORE_SERVICE_WRITE:
734 		case LWS_SSL_CAPABLE_MORE_SERVICE:
735 			goto handled;
736 		}
737 	}
738 #endif
739 
740 	if ((pollfd->revents & LWS_POLLOUT) == LWS_POLLOUT &&
741 	    wsi->tls_read_wanted_write) {
742 		/*
743 		 * If this wsi has a pending WANT_WRITE from SSL_read(), it has
744 		 * asked for a callback on writeable so it can retry the read.
745 		 *
746 		 *  Let's consume the POLLOUT by turning it into a POLLIIN, and
747 		 *  setting a flag to request a new writeable
748 		 */
749 		wsi->tls_read_wanted_write = 0;
750 		pollfd->revents &= ~(LWS_POLLOUT);
751 		pollfd->revents |= LWS_POLLIN;
752 		cow = 1;
753 	}
754 
755 	wsi->could_have_pending = 0; /* clear back-to-back write detection */
756 	pt->inside_lws_service = 1;
757 
758 	/* okay, what we came here to do... */
759 
760 	/* if we got here, we should have wire protocol ops set on the wsi */
761 	assert(wsi->role_ops);
762 
763 	// lwsl_notice("%s: %s: wsistate 0x%x\n", __func__, wsi->role_ops->name,
764 	//	    wsi->wsistate);
765 
766 	switch (lws_rops_func_fidx(wsi->role_ops, LWS_ROPS_handle_POLLIN).
767 					       handle_POLLIN(pt, wsi, pollfd)) {
768 	case LWS_HPI_RET_WSI_ALREADY_DIED:
769 		pt->inside_lws_service = 0;
770 		return 1;
771 	case LWS_HPI_RET_HANDLED:
772 		break;
773 	case LWS_HPI_RET_PLEASE_CLOSE_ME:
774 		//lwsl_notice("%s: %s pollin says please close me\n", __func__,
775 		//		wsi->role_ops->name);
776 close_and_handled:
777 		lwsl_wsi_debug(wsi, "Close and handled");
778 		lws_close_free_wsi(wsi, LWS_CLOSE_STATUS_NOSTATUS,
779 				   "close_and_handled");
780 #if defined(_DEBUG) && defined(LWS_WITH_LIBUV)
781 		/*
782 		 * confirm close has no problem being called again while
783 		 * it waits for libuv service to complete the first async
784 		 * close
785 		 */
786 		if (!strcmp(context->event_loop_ops->name, "libuv"))
787 			lws_close_free_wsi(wsi, LWS_CLOSE_STATUS_NOSTATUS,
788 					   "close_and_handled uv repeat test");
789 #endif
790 		/*
791 		 * pollfd may point to something else after the close
792 		 * due to pollfd swapping scheme on delete on some platforms
793 		 * we can't clear revents now because it'd be the wrong guy's
794 		 * revents
795 		 */
796 		pt->inside_lws_service = 0;
797 		return 1;
798 	default:
799 		assert(0);
800 	}
801 #if defined(LWS_WITH_TLS)
802 handled:
803 #endif
804 	pollfd->revents = 0;
805 	if (cow)
806 		lws_callback_on_writable(wsi);
807 	pt->inside_lws_service = 0;
808 
809 	return 0;
810 }
811 
812 int
lws_service_fd(struct lws_context * context,struct lws_pollfd * pollfd)813 lws_service_fd(struct lws_context *context, struct lws_pollfd *pollfd)
814 {
815 	return lws_service_fd_tsi(context, pollfd, 0);
816 }
817 
818 int
lws_service(struct lws_context * context,int timeout_ms)819 lws_service(struct lws_context *context, int timeout_ms)
820 {
821 	struct lws_context_per_thread *pt;
822 	int n;
823 
824 	if (!context)
825 		return 1;
826 
827 	pt = &context->pt[0];
828 	pt->inside_service = 1;
829 
830 	if (context->event_loop_ops->run_pt) {
831 		/* we are configured for an event loop */
832 		context->event_loop_ops->run_pt(context, 0);
833 
834 		pt->inside_service = 0;
835 
836 		return 1;
837 	}
838 	n = lws_plat_service(context, timeout_ms);
839 
840 	if (n != -1)
841 		pt->inside_service = 0;
842 
843 	return n;
844 }
845 
846 int
lws_service_tsi(struct lws_context * context,int timeout_ms,int tsi)847 lws_service_tsi(struct lws_context *context, int timeout_ms, int tsi)
848 {
849 	struct lws_context_per_thread *pt;
850 	int n;
851 
852 	if (!context)
853 		return 1;
854 
855 	pt = &context->pt[tsi];
856 	pt->inside_service = 1;
857 #if LWS_MAX_SMP > 1
858 	pt->self = pthread_self();
859 #endif
860 
861 	if (context->event_loop_ops->run_pt) {
862 		/* we are configured for an event loop */
863 		context->event_loop_ops->run_pt(context, tsi);
864 
865 		pt->inside_service = 0;
866 
867 		return 1;
868 	}
869 
870 	n = _lws_plat_service_tsi(context, timeout_ms, tsi);
871 
872 	pt->inside_service = 0;
873 
874 	return n;
875 }
876