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