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