src/Main/util.cxx

   1 // util.cxx - general-purpose utility functions.
   2 // Copyright (C) 2002  Curtis L. Olson  - http://www.flightgear.org/~curt
   3 //
   4 // This program is free software; you can redistribute it and/or
   5 // modify it under the terms of the GNU General Public License as
   6 // published by the Free Software Foundation; either version 2 of the
   7 // License, or (at your option) any later version.
   8 //
   9 // This program is distributed in the hope that it will be useful, but
  10 // WITHOUT ANY WARRANTY; without even the implied warranty of
  11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12 // General Public License for more details.
  13 //
  14 // You should have received a copy of the GNU General Public License
  15 // along with this program; if not, write to the Free Software
  16 // Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  17 //
  18 // $Id$
  19
  20 #ifdef HAVE_CONFIG_H
  21 #  include <config.h>
  22 #endif
  23
  24 #include <simgear/compiler.h>
  25
  26 #include <math.h>
  27
  28 #include <cstdlib>
  29
  30 #include <vector>
  31
  32 #include <simgear/debug/logstream.hxx>
  33 #include <simgear/math/SGLimits.hxx>
  34 #include <simgear/math/SGMisc.hxx>
  35
  36 #include <GUI/MessageBox.hxx>
  37 #include "fg_io.hxx"
  38 #include "fg_props.hxx"
  39 #include "globals.hxx"
  40 #include "util.hxx"
  41
  42 #ifdef OSG_LIBRARY_STATIC
  43 #include "osgDB/Registry"
  44 #endif
  45
  46 using std::vector;
  47
  48 // Originally written by Alex Perry.
  49 double
  50 fgGetLowPass (double current, double target, double timeratio)
  51 {
  52     if ( timeratio < 0.0 ) {
  53         if ( timeratio < -1.0 ) {
  54                                 // time went backwards; kill the filter
  55                 current = target;
  56         } else {
  57                                 // ignore mildly negative time
  58         }
  59     } else if ( timeratio < 0.2 ) {
  60                                 // Normal mode of operation; fast
  61                                 // approximation to exp(-timeratio)
  62         current = current * (1.0 - timeratio) + target * timeratio;
  63     } else if ( timeratio > 5.0 ) {
  64                                 // Huge time step; assume filter has settled
  65         current = target;
  66     } else {
  67                                 // Moderate time step; non linear response
  68         double keep = exp(-timeratio);
  69         current = current * keep + target * (1.0 - keep);
  70     }
  71
  72     return current;
  73 }
  74
  75 static string_list read_allowed_paths;
  76 static string_list write_allowed_paths;
  77
  78 // Allowed paths here are absolute, and may contain _one_ *,
  79 // which matches any string
  80 // FG_SCENERY is deliberately not allowed, as it would make
  81 // /sim/terrasync/scenery-dir a security hole
  82 void fgInitAllowedPaths()
  83 {
  84     read_allowed_paths.clear();
  85     write_allowed_paths.clear();
  86     read_allowed_paths.push_back(globals->get_fg_root() + "/*");
  87     read_allowed_paths.push_back(globals->get_fg_home() + "/*");
  88     string_list const aircraft_paths = globals->get_aircraft_paths();
  89     for( string_list::const_iterator it = aircraft_paths.begin();
  90                                      it != aircraft_paths.end();
  91                                    ++it )
  92     {
  93         read_allowed_paths.push_back(*it + "/*");
  94     }
  95
  96     for( string_list::const_iterator it = read_allowed_paths.begin();
  97                                      it != read_allowed_paths.end();
  98                                    ++it )
  99     { // if we get the initialization order wrong, better to have an
 100       // obvious error than a can-read-everything security hole...
 101         if (!(it->compare("/*"))){
 102             flightgear::fatalMessageBox("Nasal initialization error",
 103                                     "Empty string in FG_ROOT, FG_HOME or FG_AIRCRAFT",
 104                                     "or fgInitAllowedPaths() called too early");
 105             exit(-1);
 106         }
 107     }
 108     write_allowed_paths.push_back("/tmp/*.xml");
 109     write_allowed_paths.push_back(globals->get_fg_home() + "/*.sav");
 110     write_allowed_paths.push_back(globals->get_fg_home() + "/*.log");
 111     write_allowed_paths.push_back(globals->get_fg_home() + "/cache/*");
 112     write_allowed_paths.push_back(globals->get_fg_home() + "/Export/*");
 113     write_allowed_paths.push_back(globals->get_fg_home() + "/state/*.xml");
 114     write_allowed_paths.push_back(globals->get_fg_home() + "/aircraft-data/*.xml");
 115     write_allowed_paths.push_back(globals->get_fg_home() + "/Wildfire/*.xml");
 116     write_allowed_paths.push_back(globals->get_fg_home() + "/runtime-jetways/*.xml");
 117     write_allowed_paths.push_back(globals->get_fg_home() + "/Input/Joysticks/*.xml");
 118
 119     // Check that it works
 120     if(!fgValidatePath(globals->get_fg_home() + "/../no.log",true).empty() ||
 121         !fgValidatePath(globals->get_fg_home() + "/no.lot",true).empty() ||
 122         !fgValidatePath(globals->get_fg_home() + "/nolog",true).empty() ||
 123         !fgValidatePath(globals->get_fg_home() + "no.log",true).empty() ||
 124         !fgValidatePath("..\\" + globals->get_fg_home() + "/no.log",false).empty() ||
 125         !fgValidatePath(std::string("/tmp/no.xml"),false).empty() ||
 126         fgValidatePath(globals->get_fg_home() + "/./ff/../Export\\yes..gg",true).empty() ||
 127         fgValidatePath(globals->get_fg_home() + "/aircraft-data/yes..xml",true).empty() ||
 128         fgValidatePath(globals->get_fg_root() + "/./\\yes.bmp",false).empty()) {
 129             flightgear::fatalMessageBox("Nasal initialization error",
 130                                     "fgInitAllowedPaths() does not work",
 131                                     "");
 132             exit(-1);
 133     }
 134 }
 135
 136 // Normalize a path
 137 // Unlike SGPath::realpath, does not require that the file already exists,
 138 // but does require that it be below the starting point
 139 static std::string fgNormalizePath (const std::string& path)
 140 {
 141     string_list path_parts;
 142     char c;
 143     std::string normed_path = "", this_part = "";
 144
 145     for (int pos = 0; ; pos++) {
 146         c = path[pos];
 147         if (c == '\\') { c = '/'; }
 148         if ((c == '/') || (c == 0)) {
 149             if ((this_part == "/..") || (this_part == "..")) {
 150                 if (path_parts.empty()) { return ""; }
 151                 path_parts.pop_back();
 152             } else if ((this_part != "/.") && (this_part != "/")) {
 153                 path_parts.push_back(this_part);
 154             }
 155             this_part = "";
 156         }
 157         if (c == 0) { break; }
 158         this_part = this_part + c;
 159     }
 160     for( string_list::const_iterator it = path_parts.begin();
 161                                      it != path_parts.end();
 162                                    ++it )
 163     {
 164         normed_path.append(*it);
 165     }
 166     return normed_path;
 167  }
 168
 169
 170 // Check whether Nasal is allowed to access a path
 171 std::string fgValidatePath (const std::string& path, bool write)
 172 {
 173     const string_list& allowed_paths(write ? write_allowed_paths : read_allowed_paths);
 174     int star_pos;
 175
 176     // Normalize the path (prevents ../../.. trickery)
 177     std::string normed_path = fgNormalizePath(path);
 178
 179     // Check against each allowed pattern
 180     for( string_list::const_iterator it = allowed_paths.begin();
 181                                      it != allowed_paths.end();
 182                                    ++it )
 183     {
 184         star_pos = it->find('*');
 185         if (star_pos == std::string::npos) {
 186             if (!(it->compare(normed_path))) {
 187                 return normed_path;
 188             }
 189         } else {
 190             if ((it->size()-1 <= normed_path.size()) /* long enough to be a potential match */
 191                 && !(it->substr(0,star_pos)
 192                     .compare(normed_path.substr(0,star_pos))) /* before-star parts match */
 193                 && !(it->substr(star_pos+1,it->size()-star_pos-1)
 194                     .compare(normed_path.substr(star_pos+1+normed_path.size()-it->size(),
 195                       it->size()-star_pos-1))) /* after-star parts match */) {
 196                 return normed_path;
 197             }
 198         }
 199     }
 200     // no match found
 201     return "";
 202 }
 203 std::string fgValidatePath(const SGPath& path, bool write) { return fgValidatePath(path.str(),write); }
 204 // end of util.cxx
 205