hardware/qemu_pipe.h

   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 */