192a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly/*
292a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly * Copyright 2009, The Android Open Source Project
392a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly *
492a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly * Licensed under the Apache License, Version 2.0 (the "License");
592a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly * you may not use this file except in compliance with the License.
692a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly * You may obtain a copy of the License at
792a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly *
892a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly *     http://www.apache.org/licenses/LICENSE-2.0
992a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly *
1092a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly * Unless required by applicable law or agreed to in writing, software
1192a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly * distributed under the License is distributed on an "AS IS" BASIS,
1292a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
1392a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly * See the License for the specific language governing permissions and
1492a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly * limitations under the License.
1592a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly */
1692a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly
1792a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly/* Helper to perform abortable blocking operations on a socket:
1892a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly *   asocket_connect()
1992a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly *   asocket_accept()
2092a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly *   asocket_read()
2192a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly *   asocket_write()
2292a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly * These calls are similar to the regular syscalls, but can be aborted with:
2392a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly *   asocket_abort()
2492a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly *
2592a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly * Calling close() on a regular POSIX socket does not abort blocked syscalls on
2692a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly * that socket in other threads.
2792a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly *
2892a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly * After calling asocket_abort() the socket cannot be reused.
2992a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly *
3092a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly * Call asocket_destory() *after* all threads have finished with the socket to
3192a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly * finish closing the socket and free the asocket structure.
3292a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly *
3392a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly * The helper is implemented by setting the socket non-blocking to initiate
3492a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly * syscalls connect(), accept(), read(), write(), then using a blocking poll()
3592a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly * on both the primary socket and a local pipe. This makes the poll() abortable
3692a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly * by writing a byte to the local pipe in asocket_abort().
3792a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly *
3892a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly * asocket_create() sets the fd to non-blocking mode. It must not be changed to
3992a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly * blocking mode.
4092a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly *
4192a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly * Using asocket will triple the number of file descriptors required per
4292a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly * socket, due to the local pipe. It may be possible to use a global pipe per
4392a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly * process rather than per socket, but we have not been able to come up with a
4492a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly * race-free implementation yet.
4592a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly *
4692a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly * All functions except asocket_init() and asocket_destroy() are thread safe.
4792a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly */
4892a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly
4992a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly#include <stdlib.h>
5092a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly#include <sys/socket.h>
5192a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly
5292a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly#ifndef __CUTILS_ABORT_SOCKET_H__
5392a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly#define __CUTILS_ABORT_SOCKET_H__
5492a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly#ifdef __cplusplus
5592a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pellyextern "C" {
5692a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly#endif
5792a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly
5892a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pellystruct asocket {
5992a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly    int fd;           /* primary socket fd */
6092a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly    int abort_fd[2];  /* pipe used to abort */
6192a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly};
6292a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly
6392a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly/* Create an asocket from fd.
6492a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly * Sets the socket to non-blocking mode.
6592a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly * Returns NULL on error with errno set.
6692a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly */
6792a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pellystruct asocket *asocket_init(int fd);
6892a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly
6992a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly/* Blocking socket I/O with timeout.
7092a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly * Calling asocket_abort() from another thread will cause each of these
7192a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly * functions to immediately return with value -1 and errno ECANCELED.
7292a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly * timeout is in ms, use -1 to indicate no timeout. On timeout -1 is returned
7392a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly * with errno ETIMEDOUT.
7492a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly * EINTR is handled in-call.
7592a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly * Other semantics are identical to the regular syscalls.
7692a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly */
7792a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pellyint asocket_connect(struct asocket *s, const struct sockaddr *addr,
7892a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly        socklen_t addrlen, int timeout);
7992a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly
8092a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pellyint asocket_accept(struct asocket *s, struct sockaddr *addr,
8192a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly        socklen_t *addrlen, int timeout);
8292a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly
8392a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pellyint asocket_read(struct asocket *s, void *buf, size_t count, int timeout);
8492a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly
8592a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pellyint asocket_write(struct asocket *s, const void *buf, size_t count,
8692a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly        int timeout);
8792a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly
8892a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly/* Abort above calls and shutdown socket.
8992a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly * Further I/O operations on this socket will immediately fail after this call.
9092a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly * asocket_destroy() should be used to release resources once all threads
9192a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly * have returned from blocking calls on the socket.
9292a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly */
9392a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pellyvoid asocket_abort(struct asocket *s);
9492a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly
9592a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly/* Close socket and free asocket structure.
9692a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly * Must not be called until all calls on this structure have completed.
9792a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly */
9892a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pellyvoid asocket_destroy(struct asocket *s);
9992a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly
10092a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly#ifdef __cplusplus
10192a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly}
10292a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly#endif
10392a7541bce0f8ed7649dcbadd83b27d71e4f391fNick Pelly#endif //__CUTILS_ABORT_SOCKET__H__
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