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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 /* this file contains various functions used by all libhardware modules
18  * that support QEMU emulation
19  */
20 #include "qemu.h"
21 #define  LOG_TAG  "hardware-qemu"
22 #include <cutils/log.h>
23 #include <cutils/properties.h>
24 #include <cutils/sockets.h>
25 #include <errno.h>
26 #include <fcntl.h>
27 #include <termios.h>
28 #include <stdio.h>
29 #include <stdarg.h>
30 
31 #define  QEMU_DEBUG  0
32 
33 #if QEMU_DEBUG
34 #  define  D(...)   ALOGD(__VA_ARGS__)
35 #else
36 #  define  D(...)   ((void)0)
37 #endif
38 
39 #include "hardware/qemu_pipe.h"
40 
41 int
qemu_check(void)42 qemu_check(void)
43 {
44     static int  in_qemu = -1;
45 
46     if (__builtin_expect(in_qemu < 0,0)) {
47         char  propBuf[PROPERTY_VALUE_MAX];
48         property_get("ro.kernel.qemu", propBuf, "");
49         in_qemu = (propBuf[0] == '1');
50     }
51     return in_qemu;
52 }
53 
54 static int
qemu_fd_write(int fd,const char * cmd,int len)55 qemu_fd_write( int  fd, const char*  cmd, int  len )
56 {
57     int  len2;
58     do {
59         len2 = write(fd, cmd, len);
60     } while (len2 < 0 && errno == EINTR);
61     return len2;
62 }
63 
64 static int
qemu_fd_read(int fd,char * buff,int len)65 qemu_fd_read( int  fd, char*  buff, int  len )
66 {
67     int  len2;
68     do {
69         len2 = read(fd, buff, len);
70     } while (len2 < 0 && errno == EINTR);
71     return len2;
72 }
73 
74 static int
qemu_channel_open_qemud_pipe(QemuChannel * channel,const char * name)75 qemu_channel_open_qemud_pipe( QemuChannel*  channel,
76                               const char*   name )
77 {
78     int   fd;
79     char  pipe_name[512];
80 
81     snprintf(pipe_name, sizeof(pipe_name), "qemud:%s", name);
82     fd = qemu_pipe_open(pipe_name);
83     if (fd < 0) {
84         D("no qemud pipe: %s", strerror(errno));
85         return -1;
86     }
87 
88     channel->is_qemud = 1;
89     channel->fd       = fd;
90     return 0;
91 }
92 
93 static int
qemu_channel_open_qemud(QemuChannel * channel,const char * name)94 qemu_channel_open_qemud( QemuChannel*  channel,
95                          const char*   name )
96 {
97     int   fd, ret, namelen = strlen(name);
98     char  answer[2];
99 
100     fd = socket_local_client( "qemud",
101                               ANDROID_SOCKET_NAMESPACE_RESERVED,
102                               SOCK_STREAM );
103     if (fd < 0) {
104         D("no qemud control socket: %s", strerror(errno));
105         return -1;
106     }
107 
108     /* send service name to connect */
109     if (qemu_fd_write(fd, name, namelen) != namelen) {
110         D("can't send service name to qemud: %s",
111            strerror(errno));
112         close(fd);
113         return -1;
114     }
115 
116     /* read answer from daemon */
117     if (qemu_fd_read(fd, answer, 2) != 2 ||
118         answer[0] != 'O' || answer[1] != 'K') {
119         D("cant' connect to %s service through qemud", name);
120         close(fd);
121         return -1;
122     }
123 
124     channel->is_qemud = 1;
125     channel->fd       = fd;
126     return 0;
127 }
128 
129 
130 static int
qemu_channel_open_qemud_old(QemuChannel * channel,const char * name)131 qemu_channel_open_qemud_old( QemuChannel*  channel,
132                              const char*   name )
133 {
134     int  fd;
135 
136     snprintf(channel->device, sizeof channel->device,
137                 "qemud_%s", name);
138 
139     fd = socket_local_client( channel->device,
140                               ANDROID_SOCKET_NAMESPACE_RESERVED,
141                               SOCK_STREAM );
142     if (fd < 0) {
143         D("no '%s' control socket available: %s",
144             channel->device, strerror(errno));
145         return -1;
146     }
147 
148     close(fd);
149     channel->is_qemud_old = 1;
150     return 0;
151 }
152 
153 
154 static int
qemu_channel_open_tty(QemuChannel * channel,const char * name,int mode)155 qemu_channel_open_tty( QemuChannel*  channel,
156                        const char*   name,
157                        int           mode )
158 {
159     char   key[PROPERTY_KEY_MAX];
160     char   prop[PROPERTY_VALUE_MAX];
161     int    ret;
162 
163     ret = snprintf(key, sizeof key, "ro.kernel.android.%s", name);
164     if (ret >= (int)sizeof key)
165         return -1;
166 
167     if (property_get(key, prop, "") == 0) {
168         D("no kernel-provided %s device name", name);
169         return -1;
170     }
171 
172     ret = snprintf(channel->device, sizeof channel->device,
173                     "/dev/%s", prop);
174     if (ret >= (int)sizeof channel->device) {
175         D("%s device name too long: '%s'", name, prop);
176         return -1;
177     }
178 
179     channel->is_tty = !memcmp("/dev/tty", channel->device, 8);
180     return 0;
181 }
182 
183 int
qemu_channel_open(QemuChannel * channel,const char * name,int mode)184 qemu_channel_open( QemuChannel*  channel,
185                    const char*   name,
186                    int           mode )
187 {
188     int  fd = -1;
189 
190     /* initialize the channel is needed */
191     if (!channel->is_inited)
192     {
193         channel->is_inited = 1;
194 
195         do {
196             if (qemu_channel_open_qemud_pipe(channel, name) == 0)
197                 break;
198 
199             if (qemu_channel_open_qemud(channel, name) == 0)
200                 break;
201 
202             if (qemu_channel_open_qemud_old(channel, name) == 0)
203                 break;
204 
205             if (qemu_channel_open_tty(channel, name, mode) == 0)
206                 break;
207 
208             channel->is_available = 0;
209             return -1;
210         } while (0);
211 
212         channel->is_available = 1;
213     }
214 
215     /* try to open the file */
216     if (!channel->is_available) {
217         errno = ENOENT;
218         return -1;
219     }
220 
221     if (channel->is_qemud) {
222         return dup(channel->fd);
223     }
224 
225     if (channel->is_qemud_old) {
226         do {
227             fd = socket_local_client( channel->device,
228                                       ANDROID_SOCKET_NAMESPACE_RESERVED,
229                                       SOCK_STREAM );
230         } while (fd < 0 && errno == EINTR);
231     }
232     else /* /dev/ttySn ? */
233     {
234         do {
235             fd = open(channel->device, mode);
236         } while (fd < 0 && errno == EINTR);
237 
238         /* disable ECHO on serial lines */
239         if (fd >= 0 && channel->is_tty) {
240             struct termios  ios;
241             tcgetattr( fd, &ios );
242             ios.c_lflag = 0;  /* disable ECHO, ICANON, etc... */
243             tcsetattr( fd, TCSANOW, &ios );
244         }
245     }
246     return fd;
247 }
248 
249 
250 static int
qemu_command_vformat(char * buffer,int buffer_size,const char * format,va_list args)251 qemu_command_vformat( char*        buffer,
252                       int          buffer_size,
253                       const char*  format,
254                       va_list      args )
255 {
256     char     header[5];
257     int      len;
258 
259     if (buffer_size < 6)
260         return -1;
261 
262     len = vsnprintf(buffer+4, buffer_size-4, format, args);
263     if (len >= buffer_size-4)
264         return -1;
265 
266     snprintf(header, sizeof header, "%04x", len);
267     memcpy(buffer, header, 4);
268     return len + 4;
269 }
270 
271 extern int
qemu_command_format(char * buffer,int buffer_size,const char * format,...)272 qemu_command_format( char*        buffer,
273                      int          buffer_size,
274                      const char*  format,
275                      ... )
276 {
277     va_list  args;
278     int      ret;
279 
280     va_start(args, format);
281     ret = qemu_command_format(buffer, buffer_size, format, args);
282     va_end(args);
283     return ret;
284 }
285 
286 
287 static int
qemu_control_fd(void)288 qemu_control_fd(void)
289 {
290     static QemuChannel  channel[1];
291     int                 fd;
292 
293     fd = qemu_channel_open( channel, "hw-control", O_RDWR );
294     if (fd < 0) {
295         D("%s: could not open control channel: %s", __FUNCTION__,
296           strerror(errno));
297     }
298     return fd;
299 }
300 
301 static int
qemu_control_send(const char * cmd,int len)302 qemu_control_send(const char*  cmd, int  len)
303 {
304     int  fd, len2;
305 
306     if (len < 0) {
307         errno = EINVAL;
308         return -1;
309     }
310 
311     fd = qemu_control_fd();
312     if (fd < 0)
313         return -1;
314 
315     len2 = qemu_fd_write(fd, cmd, len);
316     close(fd);
317     if (len2 != len) {
318         D("%s: could not send everything %d < %d",
319           __FUNCTION__, len2, len);
320         return -1;
321     }
322     return 0;
323 }
324 
325 
326 int
qemu_control_command(const char * fmt,...)327 qemu_control_command( const char*  fmt, ... )
328 {
329     va_list  args;
330     char     command[256];
331     int      len, fd;
332 
333     va_start(args, fmt);
334     len = qemu_command_vformat( command, sizeof command, fmt, args );
335     va_end(args);
336 
337     if (len < 0 || len >= (int)sizeof command) {
338         if (len < 0) {
339             D("%s: could not send: %s", __FUNCTION__, strerror(errno));
340         } else {
341             D("%s: too large %d > %d", __FUNCTION__, len, (int)(sizeof command));
342         }
343         errno = EINVAL;
344         return -1;
345     }
346 
347     return qemu_control_send( command, len );
348 }
349 
qemu_control_query(const char * question,int questionlen,char * answer,int answersize)350 extern int  qemu_control_query( const char*  question, int  questionlen,
351                                 char*        answer,   int  answersize )
352 {
353     int   ret, fd, len, result = -1;
354     char  header[5], *end;
355 
356     if (questionlen <= 0) {
357         errno = EINVAL;
358         return -1;
359     }
360 
361     fd = qemu_control_fd();
362     if (fd < 0)
363         return -1;
364 
365     ret = qemu_fd_write( fd, question, questionlen );
366     if (ret != questionlen) {
367         D("%s: could not write all: %d < %d", __FUNCTION__,
368           ret, questionlen);
369         goto Exit;
370     }
371 
372     /* read a 4-byte header giving the length of the following content */
373     ret = qemu_fd_read( fd, header, 4 );
374     if (ret != 4) {
375         D("%s: could not read header (%d != 4)",
376           __FUNCTION__, ret);
377         goto Exit;
378     }
379 
380     header[4] = 0;
381     len = strtol( header, &end,  16 );
382     if ( len < 0 || end == NULL || end != header+4 || len > answersize ) {
383         D("%s: could not parse header: '%s'",
384           __FUNCTION__, header);
385         goto Exit;
386     }
387 
388     /* read the answer */
389     ret = qemu_fd_read( fd, answer, len );
390     if (ret != len) {
391         D("%s: could not read all of answer %d < %d",
392           __FUNCTION__, ret, len);
393         goto Exit;
394     }
395 
396     result = len;
397 
398 Exit:
399     close(fd);
400     return result;
401 }
402