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

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