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 #include <sys/poll.h>
39
40
41 #include <nativehelper/AsynchronousCloseMonitor.h>
42
43 extern "C" {
44
45 /*
46 * Signal to unblock thread
47 */
48 // Android-changed: Bionic (and AsynchronousCloseMonitor) expects libcore to use
49 // __SIGRTMIN + 2, not __SIGRTMAX - 2
50 static int sigWakeup = (__SIGRTMIN + 2);
51
52 /*
53 * Close or dup2 a file descriptor ensuring that all threads blocked on
54 * the file descriptor are notified via a wakeup signal.
55 *
56 * fd1 < 0 => close(fd2)
57 * fd1 >= 0 => dup2(fd1, fd2)
58 *
59 * Returns -1 with errno set if operation fails.
60 */
closefd(int fd1,int fd2)61 static int closefd(int fd1, int fd2) {
62 int rv, orig_errno;
63
64 AsynchronousCloseMonitor::signalBlockedThreads(fd2);
65
66 /*
67 * And close/dup the file descriptor
68 * (restart if interrupted by signal)
69 */
70 do {
71 if (fd1 < 0) {
72 rv = close(fd2);
73 } else {
74 rv = dup2(fd1, fd2);
75 }
76 } while (rv == -1 && errno == EINTR);
77 return rv;
78 }
79
80 /*
81 * Wrapper for dup2 - same semantics as dup2 system call except
82 * that any threads blocked in an I/O system call on fd2 will be
83 * preempted and return -1/EBADF;
84 */
NET_Dup2(int fd,int fd2)85 int NET_Dup2(int fd, int fd2) {
86 if (fd < 0) {
87 errno = EBADF;
88 return -1;
89 }
90 return closefd(fd, fd2);
91 }
92
93 /*
94 * Wrapper for close - same semantics as close system call
95 * except that any threads blocked in an I/O on fd will be
96 * preempted and the I/O system call will return -1/EBADF.
97 */
NET_SocketClose(int fd)98 int NET_SocketClose(int fd) {
99 return closefd(-1, fd);
100 }
101
102 /************** Basic I/O operations here ***************/
103
104 /*
105 * Macro to perform a blocking IO operation. Restarts
106 * automatically if interrupted by signal (other than
107 * our wakeup signal)
108 */
109 #define BLOCKING_IO_RETURN_INT(FD, FUNC) { \
110 int ret; \
111 int _syscallErrno; \
112 do { \
113 bool _wasSignaled; \
114 { \
115 AsynchronousCloseMonitor _monitor(FD); \
116 ret = FUNC; \
117 _syscallErrno = errno; \
118 _wasSignaled = _monitor.wasSignaled(); \
119 } \
120 errno = _wasSignaled ? EBADF : _syscallErrno; \
121 } while (ret == -1 && errno == EINTR); \
122 return ret; \
123 }
124
125
NET_Read(int s,void * buf,size_t len)126 int NET_Read(int s, void* buf, size_t len) {
127 BLOCKING_IO_RETURN_INT( s, recv(s, buf, len, 0) );
128 }
129
NET_ReadV(int s,const struct iovec * vector,int count)130 int NET_ReadV(int s, const struct iovec * vector, int count) {
131 BLOCKING_IO_RETURN_INT( s, readv(s, vector, count) );
132 }
133
NET_RecvFrom(int s,void * buf,int len,unsigned int flags,struct sockaddr * from,int * fromlen)134 int NET_RecvFrom(int s, void *buf, int len, unsigned int flags,
135 struct sockaddr *from, int *fromlen) {
136 socklen_t socklen = *fromlen;
137 BLOCKING_IO_RETURN_INT( s, recvfrom(s, buf, len, flags, from, &socklen) );
138 *fromlen = socklen;
139 }
140
NET_Send(int s,void * msg,int len,unsigned int flags)141 int NET_Send(int s, void *msg, int len, unsigned int flags) {
142 BLOCKING_IO_RETURN_INT( s, send(s, msg, len, flags) );
143 }
144
NET_WriteV(int s,const struct iovec * vector,int count)145 int NET_WriteV(int s, const struct iovec * vector, int count) {
146 BLOCKING_IO_RETURN_INT( s, writev(s, vector, count) );
147 }
148
NET_SendTo(int s,const void * msg,int len,unsigned int flags,const struct sockaddr * to,int tolen)149 int NET_SendTo(int s, const void *msg, int len, unsigned int
150 flags, const struct sockaddr *to, int tolen) {
151 BLOCKING_IO_RETURN_INT( s, sendto(s, msg, len, flags, to, tolen) );
152 }
153
NET_Accept(int s,struct sockaddr * addr,int * addrlen)154 int NET_Accept(int s, struct sockaddr *addr, int *addrlen) {
155 socklen_t socklen = *addrlen;
156 BLOCKING_IO_RETURN_INT( s, accept(s, addr, &socklen) );
157 *addrlen = socklen;
158 }
159
NET_Connect(int s,struct sockaddr * addr,int addrlen)160 int NET_Connect(int s, struct sockaddr *addr, int addrlen) {
161 BLOCKING_IO_RETURN_INT( s, connect(s, addr, addrlen) );
162 }
163
164 #ifndef USE_SELECT
NET_Poll(struct pollfd * ufds,unsigned int nfds,int timeout)165 int NET_Poll(struct pollfd *ufds, unsigned int nfds, int timeout) {
166 BLOCKING_IO_RETURN_INT( ufds[0].fd, poll(ufds, nfds, timeout) );
167 }
168 #else
NET_Select(int s,fd_set * readfds,fd_set * writefds,fd_set * exceptfds,struct timeval * timeout)169 int NET_Select(int s, fd_set *readfds, fd_set *writefds,
170 fd_set *exceptfds, struct timeval *timeout) {
171 BLOCKING_IO_RETURN_INT( s-1,
172 select(s, readfds, writefds, exceptfds, timeout) );
173 }
174 #endif
175
176 /*
177 * Wrapper for poll(s, timeout).
178 * Auto restarts with adjusted timeout if interrupted by
179 * signal other than our wakeup signal.
180 *
181 * If s < 0, exits early rather than delegating to poll().
182 * TODO: Investigate whether it'd be better to handle this
183 * case at the caller so that this function is never called
184 * for s < 0.
185 */
NET_Timeout(int s,long timeout)186 int NET_Timeout(int s, long timeout) {
187 long prevtime = 0, newtime;
188 struct timeval t;
189
190 /*
191 * b/27763633
192 * Avoid blocking calls to poll() for invalid sockets, e.g. when
193 * called from PlainSocketImpl_socketAccept with fd == -1.
194 */
195 if (s < 0) {
196 errno = EBADF;
197 return -1;
198 }
199
200 /*
201 * Pick up current time as may need to adjust timeout
202 */
203 if (timeout > 0) {
204 gettimeofday(&t, NULL);
205 prevtime = t.tv_sec * 1000 + t.tv_usec / 1000;
206 }
207
208 for(;;) {
209 struct pollfd pfd;
210 int rv;
211
212 /*
213 * Poll the fd. If interrupted by our wakeup signal
214 * errno will be set to EBADF.
215 */
216 pfd.fd = s;
217 pfd.events = POLLIN | POLLERR;
218
219 bool wasSignaled;
220 int syscallErrno;
221 {
222 AsynchronousCloseMonitor monitor(s);
223 rv = poll(&pfd, 1, timeout);
224 syscallErrno = errno;
225 wasSignaled = monitor.wasSignaled();
226 }
227 errno = wasSignaled ? EBADF : syscallErrno;
228
229 /*
230 * If interrupted then adjust timeout. If timeout
231 * has expired return 0 (indicating timeout expired).
232 */
233 if (rv < 0 && errno == EINTR) {
234 if (timeout > 0) {
235 gettimeofday(&t, NULL);
236 newtime = t.tv_sec * 1000 + t.tv_usec / 1000;
237 timeout -= newtime - prevtime;
238 if (timeout <= 0) {
239 return 0;
240 }
241 prevtime = newtime;
242 }
243 } else {
244 return rv;
245 }
246
247 }
248 }
249
250 }
251