content/browser/geolocation/libgps_wrapper_linux.cc

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "content/browser/geolocation/libgps_wrapper_linux.h"
   6
   7 #include <math.h>
   8 #include <dlfcn.h>
   9 #include <errno.h>
  10
  11 #include "base/logging.h"
  12 #include "base/stringprintf.h"
  13 #include "content/public/common/geoposition.h"
  14 #include "third_party/gpsd/release-3.1/gps.h"
  15
  16 COMPILE_ASSERT(GPSD_API_MAJOR_VERSION == 5, GPSD_API_version_is_not_5);
  17
  18 namespace content {
  19 namespace {
  20 const char kLibGpsName[] = "libgps.so.20";
  21 }  // namespace
  22
  23 LibGps::LibGps(void* dl_handle,
  24                gps_open_fn gps_open,
  25                gps_close_fn gps_close,
  26                gps_read_fn gps_read)
  27     : dl_handle_(dl_handle),
  28       gps_open_(gps_open),
  29       gps_close_(gps_close),
  30       gps_read_(gps_read),
  31       gps_data_(new gps_data_t),
  32       is_open_(false) {
  33   DCHECK(gps_open_);
  34   DCHECK(gps_close_);
  35   DCHECK(gps_read_);
  36 }
  37
  38 LibGps::~LibGps() {
  39   Stop();
  40   if (dl_handle_) {
  41     const int err = dlclose(dl_handle_);
  42     DCHECK_EQ(0, err) << "Error closing dl handle: " << err;
  43   }
  44 }
  45
  46 LibGps* LibGps::New() {
  47   void* dl_handle = dlopen(kLibGpsName, RTLD_LAZY);
  48   if (!dl_handle) {
  49     DLOG(WARNING) << "Could not open " << kLibGpsName << ": " << dlerror();
  50     return NULL;
  51   }
  52
  53   DLOG(INFO) << "Loaded " << kLibGpsName;
  54
  55   #define DECLARE_FN_POINTER(function)                                   \
  56     function##_fn function = reinterpret_cast<function##_fn>(            \
  57         dlsym(dl_handle, #function));                                    \
  58     if (!function) {                                                     \
  59       DLOG(WARNING) << "libgps " << #function << " error: " << dlerror(); \
  60       dlclose(dl_handle);                                                \
  61       return NULL;                                                       \
  62     }
  63   DECLARE_FN_POINTER(gps_open);
  64   DECLARE_FN_POINTER(gps_close);
  65   DECLARE_FN_POINTER(gps_read);
  66   // We don't use gps_shm_read() directly, just to make sure that libgps has
  67   // the shared memory support.
  68   typedef int (*gps_shm_read_fn)(struct gps_data_t*);
  69   DECLARE_FN_POINTER(gps_shm_read);
  70   #undef DECLARE_FN_POINTER
  71
  72   return new LibGps(dl_handle, gps_open, gps_close, gps_read);
  73 }
  74
  75 bool LibGps::Start() {
  76   if (is_open_)
  77     return true;
  78
  79 #if defined(OS_CHROMEOS)
  80   errno = 0;
  81   if (gps_open_(GPSD_SHARED_MEMORY, 0, gps_data_.get()) != 0) {
  82     // See gps.h NL_NOxxx for definition of gps_open() error numbers.
  83     DLOG(WARNING) << "gps_open() failed " << errno;
  84     return false;
  85   } else {
  86     is_open_ = true;
  87     return true;
  88   }
  89 #else  // drop the support for desktop linux for now
  90   DLOG(WARNING) << "LibGps is only supported on ChromeOS";
  91   return false;
  92 #endif
  93 }
  94 void LibGps::Stop() {
  95   if (is_open_)
  96     gps_close_(gps_data_.get());
  97   is_open_ = false;
  98 }
  99
 100 bool LibGps::Read(Geoposition* position) {
 101   DCHECK(position);
 102   position->error_code = Geoposition::ERROR_CODE_POSITION_UNAVAILABLE;
 103   if (!is_open_) {
 104       DLOG(WARNING) << "No gpsd connection";
 105       position->error_message = "No gpsd connection";
 106       return false;
 107   }
 108
 109   if (gps_read_(gps_data_.get()) < 0) {
 110       DLOG(WARNING) << "gps_read() fails";
 111       position->error_message = "gps_read() fails";
 112       return false;
 113   }
 114
 115   if (!GetPositionIfFixed(position)) {
 116       DLOG(WARNING) << "No fixed position";
 117       position->error_message = "No fixed position";
 118       return false;
 119   }
 120
 121   position->error_code = Geoposition::ERROR_CODE_NONE;
 122   position->timestamp = base::Time::Now();
 123   if (!position->Validate()) {
 124     // GetPositionIfFixed returned true, yet we've not got a valid fix.
 125     // This shouldn't happen; something went wrong in the conversion.
 126     NOTREACHED() << "Invalid position from GetPositionIfFixed: lat,long "
 127                  << position->latitude << "," << position->longitude
 128                  << " accuracy " << position->accuracy << " time "
 129                  << position->timestamp.ToDoubleT();
 130     position->error_code = Geoposition::ERROR_CODE_POSITION_UNAVAILABLE;
 131     position->error_message = "Bad fix from gps";
 132     return false;
 133   }
 134   return true;
 135 }
 136
 137 bool LibGps::GetPositionIfFixed(Geoposition* position) {
 138   DCHECK(position);
 139   if (gps_data_->status == STATUS_NO_FIX) {
 140     DVLOG(2) << "Status_NO_FIX";
 141     return false;
 142   }
 143
 144   if (isnan(gps_data_->fix.latitude) || isnan(gps_data_->fix.longitude)) {
 145     DVLOG(2) << "No valid lat/lon value";
 146     return false;
 147   }
 148
 149   position->latitude = gps_data_->fix.latitude;
 150   position->longitude = gps_data_->fix.longitude;
 151
 152   if (!isnan(gps_data_->fix.epx) && !isnan(gps_data_->fix.epy)) {
 153     position->accuracy = std::max(gps_data_->fix.epx, gps_data_->fix.epy);
 154   } else if (isnan(gps_data_->fix.epx) && !isnan(gps_data_->fix.epy)) {
 155     position->accuracy = gps_data_->fix.epy;
 156   } else if (!isnan(gps_data_->fix.epx) && isnan(gps_data_->fix.epy)) {
 157     position->accuracy = gps_data_->fix.epx;
 158   } else {
 159     // TODO(joth): Fixme. This is a workaround for http://crbug.com/99326
 160     DVLOG(2) << "libgps reported accuracy NaN, forcing to zero";
 161     position->accuracy = 0;
 162   }
 163
 164   if (gps_data_->fix.mode == MODE_3D && !isnan(gps_data_->fix.altitude)) {
 165     position->altitude = gps_data_->fix.altitude;
 166     if (!isnan(gps_data_->fix.epv))
 167       position->altitude_accuracy = gps_data_->fix.epv;
 168   }
 169
 170   if (!isnan(gps_data_->fix.track))
 171     position->heading = gps_data_->fix.track;
 172   if (!isnan(gps_data_->fix.speed))
 173     position->speed = gps_data_->fix.speed;
 174   return true;
 175 }
 176
 177 }  // namespace content