qemu_pipe.h revision 39e2630dd95ee8b9dc980fedee88966227811b1b 
1/*
2 * Copyright (C) 2011 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16#ifndef ANDROID_INCLUDE_HARDWARE_QEMU_PIPE_H
17#define ANDROID_INCLUDE_HARDWARE_QEMU_PIPE_H
18
19#include <sys/cdefs.h>
20#include <unistd.h>
21#include <fcntl.h>
22#include <sys/mman.h>
23#include <pthread.h>  /* for pthread_once() */
24#include <stdlib.h>
25#include <stdio.h>
26
27#ifndef D
28#  define  D(...)   do{}while(0)
29#endif
30
31/* Try to open a new Qemu fast-pipe. This function returns a file descriptor
32 * that can be used to communicate with a named service managed by the
33 * emulator.
34 *
35 * This file descriptor can be used as a standard pipe/socket descriptor.
36 *
37 * 'pipeName' is the name of the emulator service you want to connect to.
38 * E.g. 'opengles' or 'camera'.
39 *
40 * On success, return a valid file descriptor
41 * Returns -1 on error, and errno gives the error code, e.g.:
42 *
43 *    EINVAL  -> unknown/unsupported pipeName
44 *    ENOSYS  -> fast pipes not available in this system.
45 *
46 * ENOSYS should never happen, except if you're trying to run within a
47 * misconfigured emulator.
48 *
49 * You should be able to open several pipes to the same pipe service,
50 * except for a few special cases (e.g. GSM modem), where EBUSY will be
51 * returned if more than one client tries to connect to it.
52 */
53static __inline__ int
54qemu_pipe_open(const char*  pipeName)
55{
56    char  buff[256];
57    int   buffLen;
58    int   fd, ret;
59
60    if (pipeName == NULL || pipeName[0] == '\0') {
61        errno = EINVAL;
62        return -1;
63    }
64
65    snprintf(buff, sizeof buff, "pipe:%s", pipeName);
66
67    fd = open("/dev/qemu_pipe", O_RDWR);
68    if (fd < 0) {
69        D("%s: Could not open /dev/qemu_pipe: %s", __FUNCTION__, strerror(errno));
70        errno = ENOSYS;
71        return -1;
72    }
73
74    buffLen = strlen(buff);
75
76    ret = TEMP_FAILURE_RETRY(write(fd, buff, buffLen+1));
77    if (ret != buffLen+1) {
78        D("%s: Could not connect to %s pipe service: %s", __FUNCTION__, pipeName, strerror(errno));
79        if (ret == 0) {
80            errno = ECONNRESET;
81        } else if (ret > 0) {
82            errno = EINVAL;
83        }
84        return -1;
85    }
86
87    return fd;
88}
89
90#endif /* ANDROID_INCLUDE_HARDWARE_QEMUD_PIPE_H */
91