code.delx.au - pulseaudio/blob - src/modules/bt-proximity-helper.c

   1 /* $Id$ */
   2
   3 /*
   4  * Small SUID helper that allows us to ping a BT device. Borrows
   5  * heavily from bluez-utils' l2ping, which is licensed as GPL2+
   6  * and comes with a copyright like this:
   7  *
   8  *  Copyright (C) 2000-2001  Qualcomm Incorporated
   9  *  Copyright (C) 2002-2003  Maxim Krasnyansky <maxk@qualcomm.com>
  10  *  Copyright (C) 2002-2007  Marcel Holtmann <marcel@holtmann.org>
  11  *
  12  *
  13  *  This program is free software; you can redistribute it and/or modify
  14  *  it under the terms of the GNU General Public License as published by
  15  *  the Free Software Foundation; either version 2 of the License, or
  16  *  (at your option) any later version.
  17  *
  18  *  This program is distributed in the hope that it will be useful,
  19  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  20  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  21  *  GNU General Public License for more details.
  22  *
  23  *  You should have received a copy of the GNU General Public License
  24  *  along with this program; if not, write to the Free Software
  25  *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  26  *
  27  */
  28
  29 #ifdef HAVE_CONFIG_H
  30 #include <config.h>
  31 #endif
  32
  33 #undef NDEBUG
  34
  35 #include <assert.h>
  36 #include <stdio.h>
  37 #include <errno.h>
  38 #include <unistd.h>
  39 #include <stdlib.h>
  40 #include <sys/time.h>
  41 #include <sys/select.h>
  42
  43 #include <bluetooth/bluetooth.h>
  44 #include <bluetooth/hci.h>
  45 #include <bluetooth/hci_lib.h>
  46 #include <bluetooth/l2cap.h>
  47
  48 #define PING_STRING "PulseAudio"
  49 #define IDENT 200
  50 #define TIMEOUT 4
  51 #define INTERVAL 2
  52
  53 static void update_status(int found) {
  54     static int status = -1;
  55
  56     if (!found && status != 0)
  57         printf("-");
  58     if (found && status <= 0)
  59         printf("+");
  60
  61     fflush(stdout);
  62     status = !!found;
  63 }
  64
  65 int main(int argc, char *argv[]) {
  66     struct sockaddr_l2 addr;
  67     union {
  68         l2cap_cmd_hdr hdr;
  69         uint8_t buf[L2CAP_CMD_HDR_SIZE + sizeof(PING_STRING)];
  70     }  packet;
  71     int fd = -1;
  72     uint8_t id = IDENT;
  73     int connected = 0;
  74
  75     assert(argc == 2);
  76
  77     for (;;) {
  78         fd_set fds;
  79         struct timeval end;
  80         ssize_t r;
  81
  82         if (!connected) {
  83
  84             if (fd >= 0)
  85                 close(fd);
  86
  87             if ((fd = socket(PF_BLUETOOTH, SOCK_RAW, BTPROTO_L2CAP)) < 0) {
  88                 fprintf(stderr, "socket(PF_BLUETOOTH, SOCK_RAW, BTPROTO_L2CAP) failed: %s", strerror(errno));
  89                 goto finish;
  90             }
  91
  92             memset(&addr, 0, sizeof(addr));
  93             addr.l2_family = AF_BLUETOOTH;
  94             bacpy(&addr.l2_bdaddr, BDADDR_ANY);
  95
  96             if (bind(fd, (struct sockaddr *) &addr, sizeof(addr)) < 0) {
  97                 fprintf(stderr, "bind() failed: %s", strerror(errno));
  98                 goto finish;
  99             }
 100
 101             memset(&addr, 0, sizeof(addr));
 102             addr.l2_family = AF_BLUETOOTH;
 103             str2ba(argv[1], &addr.l2_bdaddr);
 104
 105             if (connect(fd, (struct sockaddr *) &addr, sizeof(addr)) < 0) {
 106
 107                 if (errno == EHOSTDOWN || errno == ECONNRESET || errno == ETIMEDOUT) {
 108                     update_status(0);
 109                     sleep(INTERVAL);
 110                     continue;
 111                 }
 112
 113                 fprintf(stderr, "connect() failed: %s", strerror(errno));
 114                 goto finish;
 115             }
 116
 117             connected = 1;
 118         }
 119
 120         assert(connected);
 121
 122         memset(&packet, 0, sizeof(packet));
 123         strcpy((char*) packet.buf + L2CAP_CMD_HDR_SIZE, PING_STRING);
 124         packet.hdr.ident = id;
 125         packet.hdr.len = htobs(sizeof(PING_STRING));
 126         packet.hdr.code = L2CAP_ECHO_REQ;
 127
 128         if ((r = send(fd, &packet, sizeof(packet), 0)) < 0) {
 129
 130             if (errno == EHOSTDOWN || errno == ECONNRESET || errno == ETIMEDOUT) {
 131                 update_status(0);
 132                 connected = 0;
 133                 sleep(INTERVAL);
 134                 continue;
 135             }
 136
 137             fprintf(stderr, "send() failed: %s", strerror(errno));
 138             goto finish;
 139         }
 140
 141         assert(r == sizeof(packet));
 142
 143         gettimeofday(&end, NULL);
 144         end.tv_sec += TIMEOUT;
 145
 146         for (;;) {
 147             struct timeval now, delta;
 148
 149             gettimeofday(&now, NULL);
 150
 151             if (timercmp(&end, &now, <=)) {
 152                 update_status(0);
 153                 connected = 0;
 154                 sleep(INTERVAL);
 155                 break;
 156             }
 157
 158             timersub(&end, &now, &delta);
 159
 160             FD_ZERO(&fds);
 161             FD_SET(fd, &fds);
 162
 163             if (select(fd+1, &fds, NULL, NULL, &delta) < 0) {
 164                 fprintf(stderr, "select() failed: %s", strerror(errno));
 165                 goto finish;
 166             }
 167
 168             if ((r = recv(fd, &packet, sizeof(packet), 0)) <= 0) {
 169
 170                 if (errno == EHOSTDOWN || errno == ECONNRESET || errno == ETIMEDOUT) {
 171                     update_status(0);
 172                     connected = 0;
 173                     sleep(INTERVAL);
 174                     break;
 175                 }
 176
 177                 fprintf(stderr, "send() failed: %s", r == 0 ? "EOF" : strerror(errno));
 178                 goto finish;
 179             }
 180
 181             assert(r >= L2CAP_CMD_HDR_SIZE);
 182
 183             if (packet.hdr.ident != id)
 184                 continue;
 185
 186             if (packet.hdr.code == L2CAP_ECHO_RSP || packet.hdr.code == L2CAP_COMMAND_REJ) {
 187
 188                 if (++id >= 0xFF)
 189                     id = IDENT;
 190
 191                 update_status(1);
 192                 sleep(INTERVAL);
 193                 break;
 194             }
 195         }
 196     }
 197
 198 finish:
 199
 200     if (fd >= 0)
 201         close(fd);
 202
 203     return 1;
 204 }