1/*
2 * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
3 * Copyright (c) 1996-1999 by Internet Software Consortium
4 *
5 * Permission to use, copy, modify, and distribute this software for any
6 * purpose with or without fee is hereby granted, provided that the above
7 * copyright notice and this permission notice appear in all copies.
8 *
9 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11 * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR
12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
15 * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16 */
17
18/* ev_waits.c - implement deferred function calls for the eventlib
19 * vix 05dec95 [initial]
20 */
21
22#include "port_before.h"
23#include "fd_setsize.h"
24
25#include <errno.h>
26
27#include <isc/eventlib.h>
28#include <isc/assertions.h>
29#include "eventlib_p.h"
30
31#include "port_after.h"
32
33/* Forward. */
34
35static void		print_waits(evContext_p *ctx);
36static evWaitList *	evNewWaitList(evContext_p *);
37static void		evFreeWaitList(evContext_p *, evWaitList *);
38static evWaitList *	evGetWaitList(evContext_p *, const void *, int);
39
40
41/* Public. */
42
43/*%
44 * Enter a new wait function on the queue.
45 */
46int
47evWaitFor(evContext opaqueCtx, const void *tag,
48	  evWaitFunc func, void *uap, evWaitID *id)
49{
50	evContext_p *ctx = opaqueCtx.opaque;
51	evWait *new;
52	evWaitList *wl = evGetWaitList(ctx, tag, 1);
53
54	OKNEW(new);
55	new->func = func;
56	new->uap = uap;
57	new->tag = tag;
58	new->next = NULL;
59	if (wl->last != NULL)
60		wl->last->next = new;
61	else
62		wl->first = new;
63	wl->last = new;
64	if (id != NULL)
65		id->opaque = new;
66	if (ctx->debug >= 9)
67		print_waits(ctx);
68	return (0);
69}
70
71/*%
72 * Mark runnable all waiting functions having a certain tag.
73 */
74int
75evDo(evContext opaqueCtx, const void *tag) {
76	evContext_p *ctx = opaqueCtx.opaque;
77	evWaitList *wl = evGetWaitList(ctx, tag, 0);
78	evWait *first;
79
80	if (!wl) {
81		errno = ENOENT;
82		return (-1);
83	}
84
85	first = wl->first;
86	INSIST(first != NULL);
87
88	if (ctx->waitDone.last != NULL)
89		ctx->waitDone.last->next = first;
90	else
91		ctx->waitDone.first = first;
92	ctx->waitDone.last = wl->last;
93	evFreeWaitList(ctx, wl);
94
95	return (0);
96}
97
98/*%
99 * Remove a waiting (or ready to run) function from the queue.
100 */
101int
102evUnwait(evContext opaqueCtx, evWaitID id) {
103	evContext_p *ctx = opaqueCtx.opaque;
104	evWait *this, *prev;
105	evWaitList *wl;
106	int found = 0;
107
108	this = id.opaque;
109	INSIST(this != NULL);
110	wl = evGetWaitList(ctx, this->tag, 0);
111	if (wl != NULL) {
112		for (prev = NULL, this = wl->first;
113		     this != NULL;
114		     prev = this, this = this->next)
115			if (this == (evWait *)id.opaque) {
116				found = 1;
117				if (prev != NULL)
118					prev->next = this->next;
119				else
120					wl->first = this->next;
121				if (wl->last == this)
122					wl->last = prev;
123				if (wl->first == NULL)
124					evFreeWaitList(ctx, wl);
125				break;
126			}
127	}
128
129	if (!found) {
130		/* Maybe it's done */
131		for (prev = NULL, this = ctx->waitDone.first;
132		     this != NULL;
133		     prev = this, this = this->next)
134			if (this == (evWait *)id.opaque) {
135				found = 1;
136				if (prev != NULL)
137					prev->next = this->next;
138				else
139					ctx->waitDone.first = this->next;
140				if (ctx->waitDone.last == this)
141					ctx->waitDone.last = prev;
142				break;
143			}
144	}
145
146	if (!found) {
147		errno = ENOENT;
148		return (-1);
149	}
150
151	FREE(this);
152
153	if (ctx->debug >= 9)
154		print_waits(ctx);
155
156	return (0);
157}
158
159int
160evDefer(evContext opaqueCtx, evWaitFunc func, void *uap) {
161	evContext_p *ctx = opaqueCtx.opaque;
162	evWait *new;
163
164	OKNEW(new);
165	new->func = func;
166	new->uap = uap;
167	new->tag = NULL;
168	new->next = NULL;
169	if (ctx->waitDone.last != NULL)
170		ctx->waitDone.last->next = new;
171	else
172		ctx->waitDone.first = new;
173	ctx->waitDone.last = new;
174	if (ctx->debug >= 9)
175		print_waits(ctx);
176	return (0);
177}
178
179/* Private. */
180
181static void
182print_waits(evContext_p *ctx) {
183	evWaitList *wl;
184	evWait *this;
185
186	evPrintf(ctx, 9, "wait waiting:\n");
187	for (wl = ctx->waitLists; wl != NULL; wl = wl->next) {
188		INSIST(wl->first != NULL);
189		evPrintf(ctx, 9, "  tag %p:", wl->first->tag);
190		for (this = wl->first; this != NULL; this = this->next)
191			evPrintf(ctx, 9, " %p", this);
192		evPrintf(ctx, 9, "\n");
193	}
194	evPrintf(ctx, 9, "wait done:");
195	for (this = ctx->waitDone.first; this != NULL; this = this->next)
196		evPrintf(ctx, 9, " %p", this);
197	evPrintf(ctx, 9, "\n");
198}
199
200static evWaitList *
201evNewWaitList(evContext_p *ctx) {
202	evWaitList *new;
203
204	NEW(new);
205	if (new == NULL)
206		return (NULL);
207	new->first = new->last = NULL;
208	new->prev = NULL;
209	new->next = ctx->waitLists;
210	if (new->next != NULL)
211		new->next->prev = new;
212	ctx->waitLists = new;
213	return (new);
214}
215
216static void
217evFreeWaitList(evContext_p *ctx, evWaitList *this) {
218
219	INSIST(this != NULL);
220
221	if (this->prev != NULL)
222		this->prev->next = this->next;
223	else
224		ctx->waitLists = this->next;
225	if (this->next != NULL)
226		this->next->prev = this->prev;
227	FREE(this);
228}
229
230static evWaitList *
231evGetWaitList(evContext_p *ctx, const void *tag, int should_create) {
232	evWaitList *this;
233
234	for (this = ctx->waitLists; this != NULL; this = this->next) {
235		if (this->first != NULL && this->first->tag == tag)
236			break;
237	}
238	if (this == NULL && should_create)
239		this = evNewWaitList(ctx);
240	return (this);
241}
242
243/*! \file */
244