src/FileArea.cpp

   1 //
   2 // This file is part of the aMule Project.
   3 //
   4 // Copyright (c) 2003-2008 aMule Team ( admin@amule.org / http://www.amule.org )
   5 // Copyright (c) 1998 Vadim Zeitlin ( zeitlin@dptmaths.ens-cachan.fr )
   6 //
   7 // Any parts of this program derived from the xMule, lMule or eMule project,
   8 // or contributed by third-party developers are copyrighted by their
   9 // respective authors.
  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 #ifdef HAVE_ERRNO_H
  32 #include <errno.h>
  33 #endif
  34
  35 #ifdef HAVE_SIGNAL_H
  36 #include <signal.h>
  37 #endif
  38
  39 #include "FileArea.h"           // Interface declarations.
  40 #include "Logger.h"             // Needed for AddDebugLogLineM
  41
  42 #ifdef HAVE_SYS_MMAN_H
  43 #include <sys/mman.h>
  44 #endif
  45
  46 #if !defined(HAVE_SIGACTION) || !defined(SA_SIGINFO)
  47
  48 class CFileAreaSigHandler
  49 {
  50 public:
  51         static void Init() {};
  52         static void Add(CFileArea& area) {};
  53         static void Remove(CFileArea& area) {};
  54 };
  55
  56 #else
  57
  58 class CFileAreaSigHandler
  59 {
  60 public:
  61         static void Init();
  62         static void Add(CFileArea& area);
  63         static void Remove(CFileArea& area);
  64 private:
  65         static wxMutex mutex;
  66         static CFileArea *first;
  67         static bool initialized;
  68         static struct sigaction old_segv, old_bus;
  69         static void Handler(int sig, siginfo_t *info, void *ctx);
  70 };
  71
  72 wxMutex          CFileAreaSigHandler::mutex;
  73 CFileArea *      CFileAreaSigHandler::first;
  74 bool             CFileAreaSigHandler::initialized = false;
  75 struct sigaction CFileAreaSigHandler::old_segv;
  76 struct sigaction CFileAreaSigHandler::old_bus;
  77
  78 #define PAGE_SIZE 8192u
  79
  80 /* define MAP_ANONYMOUS for Mac OS X */
  81 #if defined(MAP_ANON) && !defined(MAP_ANONYMOUS)
  82 #define MAP_ANONYMOUS MAP_ANON
  83 #endif
  84
  85 void CFileAreaSigHandler::Handler(int sig, siginfo_t *info, void *ctx)
  86 {
  87         wxMutexLocker lock(mutex);
  88         CFileArea* cur = first;
  89         while (cur) {
  90                 if (cur->m_mmap_buffer && info->si_addr >= cur->m_mmap_buffer && info->si_addr < cur->m_mmap_buffer + cur->m_length) {
  91                         cur->m_error = true;
  92                         char *start_addr = ((char *) info->si_addr) - (((unsigned long) info->si_addr) % PAGE_SIZE);
  93                         if (mmap(start_addr, PAGE_SIZE, PROT_READ, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) == MAP_FAILED) {
  94                                 struct sigaction* sa = (sig == SIGSEGV) ? &old_segv : &old_bus;
  95                                 if (sa->sa_flags & SA_SIGINFO)
  96                                         sa->sa_sigaction(sig, info, ctx);
  97                                 else if (sa->sa_handler == SIG_DFL || sa->sa_handler == SIG_IGN)
  98                                         abort();
  99                                 else
 100                                         sa->sa_handler(sig);
 101                         }
 102                         break;
 103                 }
 104                 cur = cur->m_next;
 105         }
 106 }
 107
 108 void CFileAreaSigHandler::Init()
 109 {
 110         // init error handler if needed
 111         wxMutexLocker lock(mutex);
 112         if (initialized)
 113                 return;
 114
 115         struct sigaction sa;
 116         memset(&sa, 0, sizeof(sa));
 117         sigemptyset(&sa.sa_mask);
 118         sa.sa_sigaction = Handler;
 119         sa.sa_flags = SA_NODEFER|SA_SIGINFO;
 120         if (sigaction(SIGSEGV, &sa, &old_segv))
 121                 return;
 122         if (sigaction(SIGBUS, &sa, &old_bus)) {
 123                 sigaction(SIGSEGV, &old_segv, NULL);
 124                 return;
 125         }
 126         initialized = true;
 127 }
 128
 129 void CFileAreaSigHandler::Add(CFileArea& area)
 130 {
 131         wxMutexLocker lock(mutex);
 132         area.m_next = first;
 133         first = &area;
 134 }
 135
 136 void CFileAreaSigHandler::Remove(CFileArea& area)
 137 {
 138         wxMutexLocker lock(mutex);
 139         CFileArea **cur = &first;
 140         while (*cur) {
 141                 if (*cur == &area) {
 142                         *cur = area.m_next;
 143                         area.m_next = NULL;
 144                         break;
 145                 }
 146                 cur = &(*cur)->m_next;
 147         }
 148 }
 149 #endif
 150
 151 CFileArea::CFileArea()
 152         : m_buffer(NULL), m_mmap_buffer(NULL), m_length(0), m_next(NULL), m_error(false)
 153 {
 154         CFileAreaSigHandler::Init();
 155 }
 156
 157
 158 CFileArea::~CFileArea()
 159 {
 160         Close();
 161         CheckError();
 162 }
 163
 164 bool CFileArea::Close()
 165 {
 166         if (m_buffer != NULL && m_mmap_buffer == NULL)
 167         {
 168                 delete[] m_buffer;
 169                 m_buffer = NULL;
 170         }
 171 #ifdef HAVE_MMAP
 172         #warning using experimental MMAP file reading
 173         if (m_mmap_buffer)
 174         {
 175                 munmap(m_mmap_buffer, m_length);
 176                 // remove from list
 177                 CFileAreaSigHandler::Remove(*this);
 178                 m_mmap_buffer = NULL;
 179         }
 180 #endif
 181         return true;
 182 }
 183
 184
 185 void CFileArea::Read(const CFile& file, size_t count)
 186 {
 187         Close();
 188
 189 #ifdef HAVE_MMAP
 190         const uint64 pageSize = 8192u;
 191         uint64 offset = file.GetPosition();
 192         uint64 offStart = offset & (~(pageSize-1));
 193         uint64 offEnd = offset + count;
 194         m_length = offEnd - offStart;
 195         void *p = mmap(NULL, m_length, PROT_READ, MAP_SHARED, file.fd(), offStart);
 196         if (p != MAP_FAILED)
 197         {
 198                 m_mmap_buffer = (byte*) p;
 199                 m_buffer = m_mmap_buffer + (offset - offStart);
 200                 file.Seek(offset + count);
 201
 202                 // add to list to catch errors correctly
 203                 CFileAreaSigHandler::Add(*this);
 204                 return;
 205         }
 206 #endif
 207         m_buffer = new byte[count];
 208         file.Read(m_buffer, count);
 209 }
 210
 211 bool CFileArea::Flush()
 212 {
 213         /* currently we don't support write */
 214         return true;
 215 }
 216
 217 void CFileArea::CheckError()
 218 {
 219         bool err = m_error;
 220         m_error = false;
 221         if (err)
 222                 throw CIOFailureException(wxT("Read error, failed to read from file."));
 223 }
 224