1 /*
2 * Copyright (c) 2001, 2011, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 #include <stdio.h>
27 #include <stdlib.h>
28 #include <signal.h>
29 #include <pthread.h>
30 #include <sys/types.h>
31 #include <sys/socket.h>
32 #include <sys/time.h>
33 #include <sys/resource.h>
34 #include <sys/uio.h>
35 #include <unistd.h>
36 #include <errno.h>
37
38 // Android-changed: Fix poll.h include location
39 // #include <sys/poll.h>
40 #include <poll.h>
41
42 #include <AsynchronousCloseMonitor.h>
43
44 extern "C" {
45
46 /*
47 * Signal to unblock thread
48 */
49 // Android-changed: Bionic (and AsynchronousCloseMonitor) expects libcore to use
50 // __SIGRTMIN + 2, not __SIGRTMAX - 2
51 // Also use SIGRTMAX instead of __SIGRTMAX, which is not defined by musl.
52 #if !defined (__BIONIC__)
53 static int sigWakeup = (SIGRTMAX - 2);
54 #else
55 static int sigWakeup = (__SIGRTMIN + 2);
56 #endif
57
58 /*
59 * Close or dup2 a file descriptor ensuring that all threads blocked on
60 * the file descriptor are notified via a wakeup signal.
61 *
62 * fd1 < 0 => close(fd2)
63 * fd1 >= 0 => dup2(fd1, fd2)
64 *
65 * Returns -1 with errno set if operation fails.
66 */
closefd(int fd1,int fd2)67 static int closefd(int fd1, int fd2) {
68 int rv, orig_errno;
69
70 AsynchronousCloseMonitor::signalBlockedThreads(fd2);
71
72 /*
73 * And close/dup the file descriptor
74 * (restart if interrupted by signal)
75 */
76 do {
77 if (fd1 < 0) {
78 rv = close(fd2);
79 } else {
80 rv = dup2(fd1, fd2);
81 }
82 } while (rv == -1 && errno == EINTR);
83 return rv;
84 }
85
86 /*
87 * Wrapper for dup2 - same semantics as dup2 system call except
88 * that any threads blocked in an I/O system call on fd2 will be
89 * preempted and return -1/EBADF;
90 */
NET_Dup2(int fd,int fd2)91 int NET_Dup2(int fd, int fd2) {
92 if (fd < 0) {
93 errno = EBADF;
94 return -1;
95 }
96 return closefd(fd, fd2);
97 }
98
99 /*
100 * Wrapper for close - same semantics as close system call
101 * except that any threads blocked in an I/O on fd will be
102 * preempted and the I/O system call will return -1/EBADF.
103 */
NET_SocketClose(int fd)104 int NET_SocketClose(int fd) {
105 return closefd(-1, fd);
106 }
107
108 /************** Basic I/O operations here ***************/
109
110 /*
111 * Macro to perform a blocking IO operation. Restarts
112 * automatically if interrupted by signal (other than
113 * our wakeup signal)
114 */
115 #define BLOCKING_IO_RETURN_INT(FD, FUNC) { \
116 int ret; \
117 int _syscallErrno; \
118 do { \
119 bool _wasSignaled; \
120 { \
121 AsynchronousCloseMonitor _monitor(FD); \
122 ret = FUNC; \
123 _syscallErrno = errno; \
124 _wasSignaled = _monitor.wasSignaled(); \
125 } \
126 errno = _wasSignaled ? EBADF : _syscallErrno; \
127 } while (ret == -1 && errno == EINTR); \
128 return ret; \
129 }
130
131
NET_Read(int s,void * buf,size_t len)132 int NET_Read(int s, void* buf, size_t len) {
133 BLOCKING_IO_RETURN_INT( s, recv(s, buf, len, 0) );
134 }
135
NET_ReadV(int s,const struct iovec * vector,int count)136 int NET_ReadV(int s, const struct iovec * vector, int count) {
137 BLOCKING_IO_RETURN_INT( s, readv(s, vector, count) );
138 }
139
NET_RecvFrom(int s,void * buf,int len,unsigned int flags,struct sockaddr * from,int * fromlen)140 int NET_RecvFrom(int s, void *buf, int len, unsigned int flags,
141 struct sockaddr *from, int *fromlen) {
142 socklen_t socklen = *fromlen;
143 BLOCKING_IO_RETURN_INT( s, recvfrom(s, buf, len, flags, from, &socklen) );
144 *fromlen = socklen;
145 }
146
NET_Send(int s,void * msg,int len,unsigned int flags)147 int NET_Send(int s, void *msg, int len, unsigned int flags) {
148 BLOCKING_IO_RETURN_INT( s, send(s, msg, len, flags) );
149 }
150
NET_WriteV(int s,const struct iovec * vector,int count)151 int NET_WriteV(int s, const struct iovec * vector, int count) {
152 BLOCKING_IO_RETURN_INT( s, writev(s, vector, count) );
153 }
154
NET_SendTo(int s,const void * msg,int len,unsigned int flags,const struct sockaddr * to,int tolen)155 int NET_SendTo(int s, const void *msg, int len, unsigned int
156 flags, const struct sockaddr *to, int tolen) {
157 BLOCKING_IO_RETURN_INT( s, sendto(s, msg, len, flags, to, tolen) );
158 }
159
NET_Accept(int s,struct sockaddr * addr,int * addrlen)160 int NET_Accept(int s, struct sockaddr *addr, int *addrlen) {
161 socklen_t socklen = *addrlen;
162 BLOCKING_IO_RETURN_INT( s, accept(s, addr, &socklen) );
163 *addrlen = socklen;
164 }
165
NET_Connect(int s,struct sockaddr * addr,int addrlen)166 int NET_Connect(int s, struct sockaddr *addr, int addrlen) {
167 BLOCKING_IO_RETURN_INT( s, connect(s, addr, addrlen) );
168 }
169
170 #ifndef USE_SELECT
NET_Poll(struct pollfd * ufds,unsigned int nfds,int timeout)171 int NET_Poll(struct pollfd *ufds, unsigned int nfds, int timeout) {
172 BLOCKING_IO_RETURN_INT( ufds[0].fd, poll(ufds, nfds, timeout) );
173 }
174 #else
NET_Select(int s,fd_set * readfds,fd_set * writefds,fd_set * exceptfds,struct timeval * timeout)175 int NET_Select(int s, fd_set *readfds, fd_set *writefds,
176 fd_set *exceptfds, struct timeval *timeout) {
177 BLOCKING_IO_RETURN_INT( s-1,
178 select(s, readfds, writefds, exceptfds, timeout) );
179 }
180 #endif
181
182 /*
183 * Wrapper for poll(s, timeout).
184 * Auto restarts with adjusted timeout if interrupted by
185 * signal other than our wakeup signal.
186 *
187 * If s < 0, exits early rather than delegating to poll().
188 * TODO: Investigate whether it'd be better to handle this
189 * case at the caller so that this function is never called
190 * for s < 0.
191 */
NET_Timeout(int s,long timeout)192 int NET_Timeout(int s, long timeout) {
193 long prevtime = 0, newtime;
194 struct timeval t;
195
196 /*
197 * b/27763633
198 * Avoid blocking calls to poll() for invalid sockets, e.g. when
199 * called from PlainSocketImpl_socketAccept with fd == -1.
200 */
201 if (s < 0) {
202 errno = EBADF;
203 return -1;
204 }
205
206 /*
207 * Pick up current time as may need to adjust timeout
208 */
209 if (timeout > 0) {
210 gettimeofday(&t, NULL);
211 prevtime = t.tv_sec * 1000 + t.tv_usec / 1000;
212 }
213
214 for(;;) {
215 struct pollfd pfd;
216 int rv;
217
218 /*
219 * Poll the fd. If interrupted by our wakeup signal
220 * errno will be set to EBADF.
221 */
222 pfd.fd = s;
223 pfd.events = POLLIN | POLLERR;
224
225 bool wasSignaled;
226 int syscallErrno;
227 {
228 AsynchronousCloseMonitor monitor(s);
229 rv = poll(&pfd, 1, timeout);
230 syscallErrno = errno;
231 wasSignaled = monitor.wasSignaled();
232 }
233 errno = wasSignaled ? EBADF : syscallErrno;
234
235 /*
236 * If interrupted then adjust timeout. If timeout
237 * has expired return 0 (indicating timeout expired).
238 */
239 if (rv < 0 && errno == EINTR) {
240 if (timeout > 0) {
241 gettimeofday(&t, NULL);
242 newtime = t.tv_sec * 1000 + t.tv_usec / 1000;
243 timeout -= newtime - prevtime;
244 if (timeout <= 0) {
245 return 0;
246 }
247 prevtime = newtime;
248 }
249 } else {
250 return rv;
251 }
252
253 }
254 }
255
256 }
257