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