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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
     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
     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
     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
     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
     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
    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
    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
    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
    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
    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
    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
    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
    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 
    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