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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 #ifndef _libs_hardware_qemu_h
     17 #define _libs_hardware_qemu_h
     18 
     19 #ifdef __cplusplus
     20 extern "C" {
     21 #endif
     22 
     23 /* returns 1 iff we're running in the emulator */
     24 extern int  qemu_check(void);
     25 
     26 /* a structure used to hold enough state to connect to a given
     27  * QEMU communication channel, either through a qemud socket or
     28  * a serial port.
     29  *
     30  * initialize the structure by zero-ing it out
     31  */
     32 typedef struct {
     33     char   is_inited;
     34     char   is_available;
     35     char   is_qemud;
     36     char   is_qemud_old;
     37     char   is_tty;
     38     int    fd;
     39     char   device[32];
     40 } QemuChannel;
     41 
     42 /* try to open a qemu communication channel.
     43  * returns a file descriptor on success, or -1 in case of
     44  * error.
     45  *
     46  * 'channel' must be a QemuChannel structure that is empty
     47  * on the first call. You can call this function several
     48  * time to re-open the channel using the same 'channel'
     49  * object to speed things a bit.
     50  */
     51 extern int  qemu_channel_open( QemuChannel*  channel,
     52                                const char*   name,
     53                                int           mode );
     54 
     55 /* create a command made of a 4-hexchar prefix followed
     56  * by the content. the prefix contains the content's length
     57  * in hexadecimal coding.
     58  *
     59  * 'buffer' must be at last 6 bytes
     60  * returns -1 in case of overflow, or the command's total length
     61  * otherwise (i.e. content length + 4)
     62  */
     63 extern int  qemu_command_format( char*        buffer,
     64                                  int          buffer_size,
     65                                  const char*  format,
     66                                  ... );
     67 
     68 /* directly sends a command through the 'hw-control' channel.
     69  * this will open the channel, send the formatted command, then
     70  * close the channel automatically.
     71  * returns 0 on success, or -1 on error.
     72  */
     73 extern int  qemu_control_command( const char*  fmt, ... );
     74 
     75 /* sends a question to the hw-control channel, then receive an answer in
     76  * a user-allocated buffer. returns the length of the answer, or -1
     77  * in case of error.
     78  *
     79  * 'question' *must* have been formatted through qemu_command_format
     80  */
     81 extern int  qemu_control_query( const char*  question, int  questionlen,
     82                                 char*        answer,   int  answersize );
     83 
     84 /* use QEMU_FALLBACK(call) to call a QEMU-specific callback  */
     85 /* use QEMU_FALLBACK_VOID(call) if the function returns void */
     86 #  define  QEMU_FALLBACK(x)  \
     87     do { \
     88         if (qemu_check()) \
     89             return qemu_ ## x ; \
     90     } while (0)
     91 #  define  QEMU_FALLBACK_VOID(x)  \
     92     do { \
     93         if (qemu_check()) { \
     94             qemu_ ## x ; \
     95             return; \
     96         } \
     97     } while (0)
     98 
     99 #ifdef __cplusplus
    100 }
    101 #endif
    102 
    103 #endif /* _libs_hardware_qemu_h */
    104