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

   1 /* $Id$ */
   2
   3 /***
   4   This file is part of PulseAudio.
   5
   6   Copyright 2007 Lennart Poettering
   7
   8   PulseAudio is free software; you can redistribute it and/or modify
   9   it under the terms of the GNU Lesser General Public License as published
  10   by the Free Software Foundation; either version 2 of the License,
  11   or (at your option) any later version.
  12
  13   PulseAudio is distributed in the hope that it will be useful, but
  14   WITHOUT ANY WARRANTY; without even the implied warranty of
  15   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16   General Public License for more details.
  17
  18   You should have received a copy of the GNU Lesser General Public License
  19   along with PulseAudio; if not, write to the Free Software
  20   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
  21   USA.
  22 ***/
  23
  24 /*
  25  * Small SUID helper that allows us to ping a BT device. Borrows
  26  * heavily from bluez-utils' l2ping, which is licensed as GPL2+, too
  27  * and comes with a copyright like this:
  28  *
  29  *  Copyright (C) 2000-2001  Qualcomm Incorporated
  30  *  Copyright (C) 2002-2003  Maxim Krasnyansky <maxk@qualcomm.com>
  31  *  Copyright (C) 2002-2007  Marcel Holtmann <marcel@holtmann.org>
  32  *
  33  */
  34
  35 #ifdef HAVE_CONFIG_H
  36 #include <config.h>
  37 #endif
  38
  39 #undef NDEBUG
  40
  41 #include <assert.h>
  42 #include <stdio.h>
  43 #include <errno.h>
  44 #include <unistd.h>
  45 #include <stdlib.h>
  46 #include <sys/time.h>
  47 #include <sys/select.h>
  48
  49 #include <bluetooth/bluetooth.h>
  50 #include <bluetooth/hci.h>
  51 #include <bluetooth/hci_lib.h>
  52 #include <bluetooth/l2cap.h>
  53
  54 #define PING_STRING "PulseAudio"
  55 #define IDENT 200
  56 #define TIMEOUT 4
  57 #define INTERVAL 2
  58
  59 static void update_status(int found) {
  60     static int status = -1;
  61
  62     if (!found && status != 0)
  63         printf("-");
  64     if (found && status <= 0)
  65         printf("+");
  66
  67     fflush(stdout);
  68     status = !!found;
  69 }
  70
  71 int main(int argc, char *argv[]) {
  72     struct sockaddr_l2 addr;
  73     union {
  74         l2cap_cmd_hdr hdr;
  75         uint8_t buf[L2CAP_CMD_HDR_SIZE + sizeof(PING_STRING)];
  76     }  packet;
  77     int fd = -1;
  78     uint8_t id = IDENT;
  79     int connected = 0;
  80
  81     assert(argc == 2);
  82
  83     for (;;) {
  84         fd_set fds;
  85         struct timeval end;
  86         ssize_t r;
  87
  88         if (!connected) {
  89
  90             if (fd >= 0)
  91                 close(fd);
  92
  93             if ((fd = socket(PF_BLUETOOTH, SOCK_RAW, BTPROTO_L2CAP)) < 0) {
  94                 fprintf(stderr, "socket(PF_BLUETOOTH, SOCK_RAW, BTPROTO_L2CAP) failed: %s", strerror(errno));
  95                 goto finish;
  96             }
  97
  98             memset(&addr, 0, sizeof(addr));
  99             addr.l2_family = AF_BLUETOOTH;
 100             bacpy(&addr.l2_bdaddr, BDADDR_ANY);
 101
 102             if (bind(fd, (struct sockaddr *) &addr, sizeof(addr)) < 0) {
 103                 fprintf(stderr, "bind() failed: %s", strerror(errno));
 104                 goto finish;
 105             }
 106
 107             memset(&addr, 0, sizeof(addr));
 108             addr.l2_family = AF_BLUETOOTH;
 109             str2ba(argv[1], &addr.l2_bdaddr);
 110
 111             if (connect(fd, (struct sockaddr *) &addr, sizeof(addr)) < 0) {
 112
 113                 if (errno == EHOSTDOWN || errno == ECONNRESET || errno == ETIMEDOUT) {
 114                     update_status(0);
 115                     sleep(INTERVAL);
 116                     continue;
 117                 }
 118
 119                 fprintf(stderr, "connect() failed: %s", strerror(errno));
 120                 goto finish;
 121             }
 122
 123             connected = 1;
 124         }
 125
 126         assert(connected);
 127
 128         memset(&packet, 0, sizeof(packet));
 129         strcpy((char*) packet.buf + L2CAP_CMD_HDR_SIZE, PING_STRING);
 130         packet.hdr.ident = id;
 131         packet.hdr.len = htobs(sizeof(PING_STRING));
 132         packet.hdr.code = L2CAP_ECHO_REQ;
 133
 134         if ((r = send(fd, &packet, sizeof(packet), 0)) < 0) {
 135
 136             if (errno == EHOSTDOWN || errno == ECONNRESET || errno == ETIMEDOUT) {
 137                 update_status(0);
 138                 connected = 0;
 139                 sleep(INTERVAL);
 140                 continue;
 141             }
 142
 143             fprintf(stderr, "send() failed: %s", strerror(errno));
 144             goto finish;
 145         }
 146
 147         assert(r == sizeof(packet));
 148
 149         gettimeofday(&end, NULL);
 150         end.tv_sec += TIMEOUT;
 151
 152         for (;;) {
 153             struct timeval now, delta;
 154
 155             gettimeofday(&now, NULL);
 156
 157             if (timercmp(&end, &now, <=)) {
 158                 update_status(0);
 159                 connected = 0;
 160                 sleep(INTERVAL);
 161                 break;
 162             }
 163
 164             timersub(&end, &now, &delta);
 165
 166             FD_ZERO(&fds);
 167             FD_SET(fd, &fds);
 168
 169             if (select(fd+1, &fds, NULL, NULL, &delta) < 0) {
 170                 fprintf(stderr, "select() failed: %s", strerror(errno));
 171                 goto finish;
 172             }
 173
 174             if ((r = recv(fd, &packet, sizeof(packet), 0)) <= 0) {
 175
 176                 if (errno == EHOSTDOWN || errno == ECONNRESET || errno == ETIMEDOUT) {
 177                     update_status(0);
 178                     connected = 0;
 179                     sleep(INTERVAL);
 180                     break;
 181                 }
 182
 183                 fprintf(stderr, "send() failed: %s", r == 0 ? "EOF" : strerror(errno));
 184                 goto finish;
 185             }
 186
 187             assert(r >= L2CAP_CMD_HDR_SIZE);
 188
 189             if (packet.hdr.ident != id)
 190                 continue;
 191
 192             if (packet.hdr.code == L2CAP_ECHO_RSP || packet.hdr.code == L2CAP_COMMAND_REJ) {
 193
 194                 if (++id >= 0xFF)
 195                     id = IDENT;
 196
 197                 update_status(1);
 198                 sleep(INTERVAL);
 199                 break;
 200             }
 201         }
 202     }
 203
 204 finish:
 205
 206     if (fd >= 0)
 207         close(fd);
 208
 209     return 1;
 210 }