Android Hardware Abstraction Layer
qemu_pipe.h
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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 #include <errno.h>
27 
28 #ifndef D
29 # define D(...) do{}while(0)
30 #endif
31 
32 /* Try to open a new Qemu fast-pipe. This function returns a file descriptor
33  * that can be used to communicate with a named service managed by the
34  * emulator.
35  *
36  * This file descriptor can be used as a standard pipe/socket descriptor.
37  *
38  * 'pipeName' is the name of the emulator service you want to connect to.
39  * E.g. 'opengles' or 'camera'.
40  *
41  * On success, return a valid file descriptor
42  * Returns -1 on error, and errno gives the error code, e.g.:
43  *
44  * EINVAL -> unknown/unsupported pipeName
45  * ENOSYS -> fast pipes not available in this system.
46  *
47  * ENOSYS should never happen, except if you're trying to run within a
48  * misconfigured emulator.
49  *
50  * You should be able to open several pipes to the same pipe service,
51  * except for a few special cases (e.g. GSM modem), where EBUSY will be
52  * returned if more than one client tries to connect to it.
53  */
54 static __inline__ int
55 qemu_pipe_open(const char* pipeName)
56 {
57  char buff[256];
58  int buffLen;
59  int fd, ret;
60 
61  if (pipeName == NULL || pipeName[0] == '\0') {
62  errno = EINVAL;
63  return -1;
64  }
65 
66  snprintf(buff, sizeof buff, "pipe:%s", pipeName);
67 
68  fd = open("/dev/qemu_pipe", O_RDWR);
69  if (fd < 0) {
70  D("%s: Could not open /dev/qemu_pipe: %s", __FUNCTION__, strerror(errno));
71  //errno = ENOSYS;
72  return -1;
73  }
74 
75  buffLen = strlen(buff);
76 
77  ret = TEMP_FAILURE_RETRY(write(fd, buff, buffLen+1));
78  if (ret != buffLen+1) {
79  D("%s: Could not connect to %s pipe service: %s", __FUNCTION__, pipeName, strerror(errno));
80  if (ret == 0) {
81  errno = ECONNRESET;
82  } else if (ret > 0) {
83  errno = EINVAL;
84  }
85  return -1;
86  }
87 
88  return fd;
89 }
90 
91 #endif /* ANDROID_INCLUDE_HARDWARE_QEMUD_PIPE_H */