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      1 /*
      2  * Copyright (C) 2008 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 
     17 #ifndef ANDROID_INCLUDE_HARDWARE_QEMUD_H
     18 #define ANDROID_INCLUDE_HARDWARE_QEMUD_H
     19 
     20 #include <cutils/sockets.h>
     21 #include "qemu_pipe.h"
     22 
     23 /* the following is helper code that is used by the QEMU-specific
     24  * hardware HAL modules to communicate with the emulator program
     25  * through the 'qemud' multiplexing daemon, or through the qemud
     26  * pipe.
     27  *
     28  * see the documentation comments for details in
     29  * development/emulator/qemud/qemud.c
     30  *
     31  * all definitions here are built into the HAL module to avoid
     32  * having to write a tiny shared library for this.
     33  */
     34 
     35 /* we expect the D macro to be defined to a function macro
     36  * that sends its formatted string argument(s) to the log.
     37  * If not, ignore the traces.
     38  */
     39 #ifndef D
     40 #  define  D(...)  ((void)0)
     41 #endif
     42 
     43 static __inline__ int
     44 qemud_fd_write(int  fd, const void*  buff, int  len)
     45 {
     46     int  len2;
     47     do {
     48         len2 = write(fd, buff, len);
     49     } while (len2 < 0 && errno == EINTR);
     50     return len2;
     51 }
     52 
     53 static __inline__ int
     54 qemud_fd_read(int  fd, void*  buff, int  len)
     55 {
     56     int  len2;
     57     do {
     58         len2 = read(fd, buff, len);
     59     } while (len2 < 0 && errno == EINTR);
     60     return len2;
     61 }
     62 
     63 static __inline__ int
     64 qemud_channel_open(const char*  name)
     65 {
     66     int  fd;
     67     int  namelen = strlen(name);
     68     char answer[2];
     69     char pipe_name[256];
     70 
     71     /* First, try to connect to the pipe. */
     72     snprintf(pipe_name, sizeof(pipe_name), "qemud:%s", name);
     73     fd = qemu_pipe_open(pipe_name);
     74     if (fd < 0) {
     75         D("QEMUD pipe is not available for %s: %s", name, strerror(errno));
     76         /* If pipe is not available, connect to qemud control socket */
     77         fd = socket_local_client( "qemud",
     78                                   ANDROID_SOCKET_NAMESPACE_RESERVED,
     79                                   SOCK_STREAM );
     80         if (fd < 0) {
     81             D("no qemud control socket: %s", strerror(errno));
     82             return -1;
     83         }
     84 
     85         /* send service name to connect */
     86         if (qemud_fd_write(fd, name, namelen) != namelen) {
     87             D("can't send service name to qemud: %s",
     88                strerror(errno));
     89             close(fd);
     90             return -1;
     91         }
     92 
     93         /* read answer from daemon */
     94         if (qemud_fd_read(fd, answer, 2) != 2 ||
     95             answer[0] != 'O' || answer[1] != 'K') {
     96             D("cant' connect to %s service through qemud", name);
     97             close(fd);
     98             return -1;
     99         }
    100     }
    101     return fd;
    102 }
    103 
    104 static __inline__ int
    105 qemud_channel_send(int  fd, const void*  msg, int  msglen)
    106 {
    107     char  header[5];
    108 
    109     if (msglen < 0)
    110         msglen = strlen((const char*)msg);
    111 
    112     if (msglen == 0)
    113         return 0;
    114 
    115     snprintf(header, sizeof header, "%04x", msglen);
    116     if (qemud_fd_write(fd, header, 4) != 4) {
    117         D("can't write qemud frame header: %s", strerror(errno));
    118         return -1;
    119     }
    120 
    121     if (qemud_fd_write(fd, msg, msglen) != msglen) {
    122         D("can4t write qemud frame payload: %s", strerror(errno));
    123         return -1;
    124     }
    125     return 0;
    126 }
    127 
    128 static __inline__ int
    129 qemud_channel_recv(int  fd, void*  msg, int  msgsize)
    130 {
    131     char  header[5];
    132     int   size, avail;
    133 
    134     if (qemud_fd_read(fd, header, 4) != 4) {
    135         D("can't read qemud frame header: %s", strerror(errno));
    136         return -1;
    137     }
    138     header[4] = 0;
    139     if (sscanf(header, "%04x", &size) != 1) {
    140         D("malformed qemud frame header: '%.*s'", 4, header);
    141         return -1;
    142     }
    143     if (size > msgsize)
    144         return -1;
    145 
    146     if (qemud_fd_read(fd, msg, size) != size) {
    147         D("can't read qemud frame payload: %s", strerror(errno));
    148         return -1;
    149     }
    150     return size;
    151 }
    152 
    153 #endif /* ANDROID_INCLUDE_HARDWARE_QEMUD_H */
    154