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1 : /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
2 : /* This Source Code Form is subject to the terms of the Mozilla Public
3 : * License, v. 2.0. If a copy of the MPL was not distributed with this
4 : * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
5 :
6 : /*
7 : *********************************************************************
8 : *
9 : * Pollable events
10 : *
11 : * Pollable events are implemented using layered I/O. The only
12 : * I/O methods that are implemented for pollable events are poll
13 : * and close. No other methods can be invoked on a pollable
14 : * event.
15 : *
16 : * A pipe or socket pair is created and the pollable event layer
17 : * is pushed onto the read end. A pointer to the write end is
18 : * saved in the PRFilePrivate structure of the pollable event.
19 : *
20 : *********************************************************************
21 : */
22 :
23 : #include "prinit.h"
24 : #include "prio.h"
25 : #include "prmem.h"
26 : #include "prerror.h"
27 : #include "prlog.h"
28 :
29 : /*
30 : * These internal functions are declared in primpl.h,
31 : * but we can't include primpl.h because the definition
32 : * of struct PRFilePrivate in this file (for the pollable
33 : * event layer) will conflict with the definition of
34 : * struct PRFilePrivate in primpl.h (for the NSPR layer).
35 : */
36 : extern PRIntn _PR_InvalidInt(void);
37 : extern PRInt64 _PR_InvalidInt64(void);
38 : extern PRStatus _PR_InvalidStatus(void);
39 : extern PRFileDesc *_PR_InvalidDesc(void);
40 :
41 : /*
42 : * PRFilePrivate structure for the NSPR pollable events layer
43 : */
44 : struct PRFilePrivate {
45 : PRFileDesc *writeEnd; /* the write end of the pipe/socketpair */
46 : };
47 :
48 : static PRStatus PR_CALLBACK _pr_PolEvtClose(PRFileDesc *fd);
49 :
50 : static PRInt16 PR_CALLBACK _pr_PolEvtPoll(
51 : PRFileDesc *fd, PRInt16 in_flags, PRInt16 *out_flags);
52 :
53 : static PRIOMethods _pr_polevt_methods = {
54 : PR_DESC_LAYERED,
55 : _pr_PolEvtClose,
56 : (PRReadFN)_PR_InvalidInt,
57 : (PRWriteFN)_PR_InvalidInt,
58 : (PRAvailableFN)_PR_InvalidInt,
59 : (PRAvailable64FN)_PR_InvalidInt64,
60 : (PRFsyncFN)_PR_InvalidStatus,
61 : (PRSeekFN)_PR_InvalidInt,
62 : (PRSeek64FN)_PR_InvalidInt64,
63 : (PRFileInfoFN)_PR_InvalidStatus,
64 : (PRFileInfo64FN)_PR_InvalidStatus,
65 : (PRWritevFN)_PR_InvalidInt,
66 : (PRConnectFN)_PR_InvalidStatus,
67 : (PRAcceptFN)_PR_InvalidDesc,
68 : (PRBindFN)_PR_InvalidStatus,
69 : (PRListenFN)_PR_InvalidStatus,
70 : (PRShutdownFN)_PR_InvalidStatus,
71 : (PRRecvFN)_PR_InvalidInt,
72 : (PRSendFN)_PR_InvalidInt,
73 : (PRRecvfromFN)_PR_InvalidInt,
74 : (PRSendtoFN)_PR_InvalidInt,
75 : _pr_PolEvtPoll,
76 : (PRAcceptreadFN)_PR_InvalidInt,
77 : (PRTransmitfileFN)_PR_InvalidInt,
78 : (PRGetsocknameFN)_PR_InvalidStatus,
79 : (PRGetpeernameFN)_PR_InvalidStatus,
80 : (PRReservedFN)_PR_InvalidInt,
81 : (PRReservedFN)_PR_InvalidInt,
82 : (PRGetsocketoptionFN)_PR_InvalidStatus,
83 : (PRSetsocketoptionFN)_PR_InvalidStatus,
84 : (PRSendfileFN)_PR_InvalidInt,
85 : (PRConnectcontinueFN)_PR_InvalidStatus,
86 : (PRReservedFN)_PR_InvalidInt,
87 : (PRReservedFN)_PR_InvalidInt,
88 : (PRReservedFN)_PR_InvalidInt,
89 : (PRReservedFN)_PR_InvalidInt
90 : };
91 :
92 : static PRDescIdentity _pr_polevt_id;
93 : static PRCallOnceType _pr_polevt_once_control;
94 : static PRStatus PR_CALLBACK _pr_PolEvtInit(void);
95 :
96 0 : static PRInt16 PR_CALLBACK _pr_PolEvtPoll(
97 : PRFileDesc *fd, PRInt16 in_flags, PRInt16 *out_flags)
98 : {
99 0 : return (fd->lower->methods->poll)(fd->lower, in_flags, out_flags);
100 : }
101 :
102 0 : static PRStatus PR_CALLBACK _pr_PolEvtInit(void)
103 : {
104 0 : _pr_polevt_id = PR_GetUniqueIdentity("NSPR pollable events");
105 0 : if (PR_INVALID_IO_LAYER == _pr_polevt_id) {
106 0 : return PR_FAILURE;
107 : }
108 0 : return PR_SUCCESS;
109 : }
110 :
111 : #if !defined(XP_UNIX)
112 : #define USE_TCP_SOCKETPAIR
113 : #endif
114 :
115 : PR_IMPLEMENT(PRFileDesc *) PR_NewPollableEvent(void)
116 : {
117 : PRFileDesc *event;
118 : PRFileDesc *fd[2]; /* fd[0] is the read end; fd[1] is the write end */
119 : #ifdef USE_TCP_SOCKETPAIR
120 : PRSocketOptionData socket_opt;
121 : PRStatus rv;
122 : #endif
123 :
124 0 : fd[0] = fd[1] = NULL;
125 :
126 0 : if (PR_CallOnce(&_pr_polevt_once_control, _pr_PolEvtInit) == PR_FAILURE) {
127 0 : return NULL;
128 : }
129 :
130 0 : event = PR_CreateIOLayerStub(_pr_polevt_id, &_pr_polevt_methods);
131 0 : if (NULL == event) {
132 0 : goto errorExit;
133 : }
134 0 : event->secret = PR_NEW(PRFilePrivate);
135 0 : if (event->secret == NULL) {
136 0 : PR_SetError(PR_OUT_OF_MEMORY_ERROR, 0);
137 0 : goto errorExit;
138 : }
139 :
140 : #ifndef USE_TCP_SOCKETPAIR
141 0 : if (PR_CreatePipe(&fd[0], &fd[1]) == PR_FAILURE) {
142 0 : fd[0] = fd[1] = NULL;
143 0 : goto errorExit;
144 : }
145 : #else
146 : if (PR_NewTCPSocketPair(fd) == PR_FAILURE) {
147 : fd[0] = fd[1] = NULL;
148 : goto errorExit;
149 : }
150 : /*
151 : * set the TCP_NODELAY option to reduce notification latency
152 : */
153 : socket_opt.option = PR_SockOpt_NoDelay;
154 : socket_opt.value.no_delay = PR_TRUE;
155 : rv = PR_SetSocketOption(fd[1], &socket_opt);
156 : PR_ASSERT(PR_SUCCESS == rv);
157 : #endif
158 :
159 0 : event->secret->writeEnd = fd[1];
160 0 : if (PR_PushIOLayer(fd[0], PR_TOP_IO_LAYER, event) == PR_FAILURE) {
161 0 : goto errorExit;
162 : }
163 :
164 0 : return fd[0];
165 :
166 : errorExit:
167 0 : if (fd[0]) {
168 0 : PR_Close(fd[0]);
169 0 : PR_Close(fd[1]);
170 : }
171 0 : if (event) {
172 0 : PR_DELETE(event->secret);
173 0 : event->dtor(event);
174 : }
175 0 : return NULL;
176 : }
177 :
178 0 : static PRStatus PR_CALLBACK _pr_PolEvtClose(PRFileDesc *fd)
179 : {
180 : PRFileDesc *event;
181 :
182 0 : event = PR_PopIOLayer(fd, PR_TOP_IO_LAYER);
183 0 : PR_ASSERT(NULL == event->higher && NULL == event->lower);
184 0 : PR_Close(fd);
185 0 : PR_Close(event->secret->writeEnd);
186 0 : PR_DELETE(event->secret);
187 0 : event->dtor(event);
188 0 : return PR_SUCCESS;
189 : }
190 :
191 : PR_IMPLEMENT(PRStatus) PR_DestroyPollableEvent(PRFileDesc *event)
192 : {
193 0 : return PR_Close(event);
194 : }
195 :
196 : static const char magicChar = '\x38';
197 :
198 : PR_IMPLEMENT(PRStatus) PR_SetPollableEvent(PRFileDesc *event)
199 : {
200 0 : if (PR_Write(event->secret->writeEnd, &magicChar, 1) != 1) {
201 0 : return PR_FAILURE;
202 : }
203 0 : return PR_SUCCESS;
204 : }
205 :
206 : PR_IMPLEMENT(PRStatus) PR_WaitForPollableEvent(PRFileDesc *event)
207 : {
208 : char buf[1024];
209 : PRInt32 nBytes;
210 : #ifdef DEBUG
211 : PRIntn i;
212 : #endif
213 :
214 0 : nBytes = PR_Read(event->lower, buf, sizeof(buf));
215 0 : if (nBytes == -1) {
216 0 : return PR_FAILURE;
217 : }
218 :
219 : #ifdef DEBUG
220 : /*
221 : * Make sure people do not write to the pollable event fd
222 : * directly.
223 : */
224 0 : for (i = 0; i < nBytes; i++) {
225 0 : PR_ASSERT(buf[i] == magicChar);
226 : }
227 : #endif
228 :
229 0 : return PR_SUCCESS;
230 : }
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