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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 <string.h>
     27 #include <errno.h>
     28 
     29 #ifndef D
     30 #  define  D(...)   do{}while(0)
     31 #endif
     32 
     33 static bool WriteFully(int fd, const void* data, size_t byte_count) {
     34   const uint8_t* p = (const uint8_t*)(data);
     35   size_t remaining = byte_count;
     36   while (remaining > 0) {
     37     ssize_t n = TEMP_FAILURE_RETRY(write(fd, p, remaining));
     38     if (n == -1) return false;
     39     p += n;
     40     remaining -= n;
     41   }
     42   return true;
     43 }
     44 
     45 /* Try to open a new Qemu fast-pipe. This function returns a file descriptor
     46  * that can be used to communicate with a named service managed by the
     47  * emulator.
     48  *
     49  * This file descriptor can be used as a standard pipe/socket descriptor.
     50  *
     51  * 'pipeName' is the name of the emulator service you want to connect to.
     52  * E.g. 'opengles' or 'camera'.
     53  *
     54  * On success, return a valid file descriptor
     55  * Returns -1 on error, and errno gives the error code, e.g.:
     56  *
     57  *    EINVAL  -> unknown/unsupported pipeName
     58  *    ENOSYS  -> fast pipes not available in this system.
     59  *
     60  * ENOSYS should never happen, except if you're trying to run within a
     61  * misconfigured emulator.
     62  *
     63  * You should be able to open several pipes to the same pipe service,
     64  * except for a few special cases (e.g. GSM modem), where EBUSY will be
     65  * returned if more than one client tries to connect to it.
     66  */
     67 static __inline__ int
     68 qemu_pipe_open(const char*  pipeName)
     69 {
     70     char  buff[256];
     71     int   buffLen;
     72     int   fd, ret;
     73 
     74     if (pipeName == NULL || pipeName[0] == '\0') {
     75         errno = EINVAL;
     76         return -1;
     77     }
     78 
     79     snprintf(buff, sizeof buff, "pipe:%s", pipeName);
     80 
     81     fd = TEMP_FAILURE_RETRY(open("/dev/qemu_pipe", O_RDWR));
     82     if (fd < 0 && errno == ENOENT)
     83         fd = TEMP_FAILURE_RETRY(open("/dev/goldfish_pipe", O_RDWR));
     84     if (fd < 0) {
     85         D("%s: Could not open /dev/qemu_pipe: %s", __FUNCTION__, strerror(errno));
     86         //errno = ENOSYS;
     87         return -1;
     88     }
     89 
     90     buffLen = strlen(buff);
     91 
     92     if (!WriteFully(fd, buff, buffLen + 1)) {
     93         D("%s: Could not connect to %s pipe service: %s", __FUNCTION__, pipeName, strerror(errno));
     94         return -1;
     95     }
     96 
     97     return fd;
     98 }
     99 
    100 #endif /* ANDROID_INCLUDE_HARDWARE_QEMU_PIPE_H */
    101