diff options
Diffstat (limited to 'library/dir_lock.cpp')
| -rw-r--r-- | library/dir_lock.cpp | 126 |
1 files changed, 64 insertions, 62 deletions
diff --git a/library/dir_lock.cpp b/library/dir_lock.cpp index f653fa7c..7feb51ff 100644 --- a/library/dir_lock.cpp +++ b/library/dir_lock.cpp @@ -17,6 +17,7 @@ #include "../shared/serialize.h" #include "../shared/build_info.h" #include "../shared/int64.h" +#include "../shared/file_handling.h" #ifdef FFS_WIN #include <tlhelp32.h> @@ -24,7 +25,6 @@ #include "../shared/long_path_prefix.h" #elif defined FFS_LINUX -#include "../shared/file_handling.h" #include <sys/stat.h> #include <cerrno> #include <unistd.h> @@ -78,17 +78,15 @@ public: //although CreateFile/FILE_APPEND_DATA without SetFilePointerEx works locally, it MAY NOT work on some network shares creating a 4 gig file!!! const HANDLE fileHandle = ::CreateFile(applyLongPathPrefix(lockfilename_.c_str()).c_str(), - FILE_GENERIC_WRITE, + GENERIC_READ | GENERIC_WRITE, //use both when writing over network, see comment in file_io.cpp FILE_SHARE_READ, - NULL, + 0, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL); if (fileHandle == INVALID_HANDLE_VALUE) return; - - Loki::ScopeGuard dummy = Loki::MakeGuard(::CloseHandle, fileHandle); - (void)dummy; //silence warning "unused variable" + LOKI_ON_BLOCK_EXIT2(::CloseHandle(fileHandle)); const LARGE_INTEGER moveDist = {}; if (!::SetFilePointerEx(fileHandle, //__in HANDLE hFile, @@ -108,9 +106,7 @@ public: const int fileHandle = ::open(lockfilename_.c_str(), O_WRONLY | O_APPEND); //O_EXCL contains a race condition on NFS file systems: http://linux.die.net/man/2/open if (fileHandle == -1) return; - - Loki::ScopeGuard dummy = Loki::MakeGuard(::close, fileHandle); - (void)dummy; //silence warning "unused variable" + LOKI_ON_BLOCK_EXIT2(::close(fileHandle)); const ssize_t bytesWritten = ::write(fileHandle, buffer, 1); (void)bytesWritten; @@ -124,20 +120,7 @@ private: namespace { -void deleteLockFile(const Zstring& filename) //throw (FileError) -{ -#ifdef FFS_WIN - if (!::DeleteFile(applyLongPathPrefix(filename).c_str())) -#elif defined FFS_LINUX - if (::unlink(filename.c_str()) != 0) -#endif - { - throw FileError(_("Error deleting file:") + "\n\"" + filename + "\"" + "\n\n" + getLastErrorFormatted()); - } -} - - -zen::UInt64 getLockFileSize(const Zstring& filename) //throw (FileError, ErrorNotExisting) +UInt64 getLockFileSize(const Zstring& filename) //throw FileError, ErrorNotExisting { #ifdef FFS_WIN WIN32_FIND_DATA fileInfo = {}; @@ -192,13 +175,13 @@ namespace { //read string from file stream inline -std::string readString(wxInputStream& stream) //throw (std::exception) +std::string readString(wxInputStream& stream) //throw std::exception { - const boost::uint32_t strLength = readPOD<boost::uint32_t>(stream); + const auto strLength = readPOD<boost::uint32_t>(stream); std::string output; if (strLength > 0) { - output.resize(strLength); //may throw for corrupted data + output.resize(strLength); //throw std::bad_alloc stream.Read(&output[0], strLength); } return output; @@ -208,9 +191,8 @@ std::string readString(wxInputStream& stream) //throw (std::exception) inline void writeString(wxOutputStream& stream, const std::string& str) //write string to filestream { - const boost::uint32_t strLength = static_cast<boost::uint32_t>(str.length()); - writePOD<boost::uint32_t>(stream, strLength); - stream.Write(str.c_str(), strLength); + writePOD(stream, static_cast<boost::uint32_t>(str.length())); + stream.Write(str.c_str(), str.length()); } @@ -242,7 +224,7 @@ struct LockInformation LockInformation(wxInputStream& stream) //read { char formatDescr[sizeof(LOCK_FORMAT_DESCR)] = {}; - stream.Read(formatDescr, sizeof(LOCK_FORMAT_DESCR)); //file format header + stream.Read(formatDescr, sizeof(LOCK_FORMAT_DESCR)); //file format header const int lockFileVersion = readPOD<boost::int32_t>(stream); // (void)lockFileVersion; @@ -286,6 +268,7 @@ enum ProcessStatus { PROC_STATUS_NOT_RUNNING, PROC_STATUS_RUNNING, + PROC_STATUS_ITS_US, PROC_STATUS_NO_IDEA }; ProcessStatus getProcessStatus(const LockInformation::ProcessDescription& procDescr) @@ -295,15 +278,16 @@ ProcessStatus getProcessStatus(const LockInformation::ProcessDescription& procDe return PROC_STATUS_NO_IDEA; //lock owned by different computer #ifdef FFS_WIN + if (procDescr.processId == ::GetCurrentProcessId()) //may seem obscure, but it's possible: a lock file is "stolen" and put back while the program is running + return PROC_STATUS_ITS_US; + //note: ::OpenProcess() is no option as it may successfully return for crashed processes! HANDLE snapshot = ::CreateToolhelp32Snapshot( TH32CS_SNAPPROCESS, //__in DWORD dwFlags, 0); //__in DWORD th32ProcessID if (snapshot == INVALID_HANDLE_VALUE) return PROC_STATUS_NO_IDEA; - - Loki::ScopeGuard dummy = Loki::MakeGuard(::CloseHandle, snapshot); - (void)dummy; //silence warning "unused variable" + LOKI_ON_BLOCK_EXIT2(::CloseHandle(snapshot)); PROCESSENTRY32 processEntry = {}; processEntry.dwSize = sizeof(processEntry); @@ -316,11 +300,14 @@ ProcessStatus getProcessStatus(const LockInformation::ProcessDescription& procDe if (processEntry.th32ProcessID == procDescr.processId) return PROC_STATUS_RUNNING; //process still running } - while(::Process32Next(snapshot, &processEntry)); + while (::Process32Next(snapshot, &processEntry)); return PROC_STATUS_NOT_RUNNING; #elif defined FFS_LINUX + if (procDescr.processId == ::getpid()) //may seem obscure, but it's possible: a lock file is "stolen" and put back while the program is running + return PROC_STATUS_ITS_US; + if (procDescr.processId <= 0 || procDescr.processId >= 65536) return PROC_STATUS_NO_IDEA; //invalid process id @@ -329,30 +316,30 @@ ProcessStatus getProcessStatus(const LockInformation::ProcessDescription& procDe } -void writeLockInfo(const Zstring& lockfilename) //throw (FileError) +void writeLockInfo(const Zstring& lockfilename) //throw FileError { //write GUID at the beginning of the file: this ID is a universal identifier for this lock (no matter what the path is, considering symlinks, distributed network, etc.) - FileOutputStream lockFile(lockfilename); //throw (FileError) + FileOutputStream lockFile(lockfilename); //throw FileError LockInformation().toStream(lockFile); } -LockInformation retrieveLockInfo(const Zstring& lockfilename) //throw (FileError, ErrorNotExisting) +LockInformation retrieveLockInfo(const Zstring& lockfilename) //throw FileError, ErrorNotExisting { //read GUID from beginning of file - FileInputStream lockFile(lockfilename); //throw (FileError, ErrorNotExisting) + FileInputStream lockFile(lockfilename); //throw FileError, ErrorNotExisting return LockInformation(lockFile); } -std::string retrieveLockId(const Zstring& lockfilename) //throw (FileError, ErrorNotExisting) +std::string retrieveLockId(const Zstring& lockfilename) //throw FileError, ErrorNotExisting { return retrieveLockInfo(lockfilename).lockId; } } -void waitOnDirLock(const Zstring& lockfilename, DirLockCallback* callback) //throw (FileError) +void waitOnDirLock(const Zstring& lockfilename, DirLockCallback* callback) //throw FileError { std::wstring infoMsg = _("Waiting while directory is locked (%x)..."); replace(infoMsg, L"%x", std::wstring(L"\"") + lockfilename + "\""); @@ -361,15 +348,26 @@ void waitOnDirLock(const Zstring& lockfilename, DirLockCallback* callback) //thr //--------------------------------------------------------------- try { - const LockInformation lockInfo = retrieveLockInfo(lockfilename); //throw (FileError, ErrorNotExisting) - const bool lockOwnderDead = getProcessStatus(lockInfo.procDescr) == PROC_STATUS_NOT_RUNNING; //convenience optimization: if we know the owning process crashed, we needn't wait DETECT_EXITUS_INTERVAL sec + const LockInformation lockInfo = retrieveLockInfo(lockfilename); //throw FileError, ErrorNotExisting + + bool lockOwnderDead = false; //convenience optimization: if we know the owning process crashed, we needn't wait DETECT_EXITUS_INTERVAL sec + switch (getProcessStatus(lockInfo.procDescr)) + { + case PROC_STATUS_ITS_US: //since we've already passed LockAdmin, the lock file seems abandoned ("stolen"?) although it's from this process + case PROC_STATUS_NOT_RUNNING: + lockOwnderDead = true; + break; + case PROC_STATUS_RUNNING: + case PROC_STATUS_NO_IDEA: + break; + } zen::UInt64 fileSizeOld; wxLongLong lockSilentStart = wxGetLocalTimeMillis(); while (true) { - const zen::UInt64 fileSizeNew = ::getLockFileSize(lockfilename); //throw (FileError, ErrorNotExisting) + const zen::UInt64 fileSizeNew = ::getLockFileSize(lockfilename); //throw FileError, ErrorNotExisting wxLongLong currentTime = wxGetLocalTimeMillis(); if (fileSizeNew != fileSizeOld) @@ -382,17 +380,17 @@ void waitOnDirLock(const Zstring& lockfilename, DirLockCallback* callback) //thr if (lockOwnderDead || //no need to wait any longer... currentTime - lockSilentStart > DETECT_EXITUS_INTERVAL) { - DirLock dummy(deleteAbandonedLockName(lockfilename), callback); //throw (FileError) + DirLock dummy(deleteAbandonedLockName(lockfilename), callback); //throw FileError //now that the lock is in place check existence again: meanwhile another process may have deleted and created a new lock! - if (retrieveLockId(lockfilename) != lockInfo.lockId) //throw (FileError, ErrorNotExisting) + if (retrieveLockId(lockfilename) != lockInfo.lockId) //throw FileError, ErrorNotExisting return; //another process has placed a new lock, leave scope: the wait for the old lock is technically over... - if (getLockFileSize(lockfilename) != fileSizeOld) //throw (FileError, ErrorNotExisting) + if (getLockFileSize(lockfilename) != fileSizeOld) //throw FileError, ErrorNotExisting continue; //belated lifesign - ::deleteLockFile(lockfilename); //throw (FileError) + removeFile(lockfilename); //throw FileError return; } @@ -432,24 +430,28 @@ void releaseLock(const Zstring& lockfilename) //throw () { try { - ::deleteLockFile(lockfilename); + removeFile(lockfilename); } - catch(...) {} + catch (...) {} } -bool tryLock(const Zstring& lockfilename) //throw (FileError) +bool tryLock(const Zstring& lockfilename) //throw FileError { #ifdef FFS_WIN const HANDLE fileHandle = ::CreateFile(applyLongPathPrefix(lockfilename).c_str(), - GENERIC_WRITE, + GENERIC_READ | GENERIC_WRITE, //use both when writing over network, see comment in file_io.cpp FILE_SHARE_READ, - NULL, + 0, CREATE_NEW, FILE_ATTRIBUTE_NORMAL, NULL); if (fileHandle == INVALID_HANDLE_VALUE) { +#ifndef _MSC_VER +#warning fix this problem! + //read-only FTP may return: ERROR_FILE_EXISTS (NetDrive @ GNU) +#endif if (::GetLastError() == ERROR_FILE_EXISTS) return false; else @@ -471,10 +473,10 @@ bool tryLock(const Zstring& lockfilename) //throw (FileError) ::close(fileHandle); #endif - Loki::ScopeGuard guardLockFile = Loki::MakeGuard(::releaseLock, lockfilename); + Loki::ScopeGuard guardLockFile = Loki::MakeGuard(zen::removeFile, lockfilename); //write UUID at the beginning of the file: this ID is a universal identifier for this lock (no matter what the path is, considering symlinks, etc.) - writeLockInfo(lockfilename); //throw (FileError) + writeLockInfo(lockfilename); //throw FileError guardLockFile.Dismiss(); //lockfile created successfully return true; @@ -485,10 +487,10 @@ bool tryLock(const Zstring& lockfilename) //throw (FileError) class DirLock::SharedDirLock { public: - SharedDirLock(const Zstring& lockfilename, DirLockCallback* callback = NULL) : //throw (FileError) + SharedDirLock(const Zstring& lockfilename, DirLockCallback* callback = NULL) : //throw FileError lockfilename_(lockfilename) { - while (!::tryLock(lockfilename)) //throw (FileError) + while (!::tryLock(lockfilename)) //throw FileError ::waitOnDirLock(lockfilename, callback); // threadObj = boost::thread(LifeSigns(lockfilename)); @@ -522,7 +524,7 @@ public: } //create or retrieve a SharedDirLock - std::shared_ptr<SharedDirLock> retrieve(const Zstring& lockfilename, DirLockCallback* callback) //throw (FileError) + std::shared_ptr<SharedDirLock> retrieve(const Zstring& lockfilename, DirLockCallback* callback) //throw FileError { //optimization: check if there is an active(!) lock for "lockfilename" FileToUuidMap::const_iterator iterUuid = fileToUuid.find(lockfilename); @@ -535,7 +537,7 @@ public: try //actual check based on lock UUID, deadlock prevention: "lockfilename" may be an alternative name for an already active lock { - const std::string lockId = retrieveLockId(lockfilename); //throw (FileError, ErrorNotExisting) + const std::string lockId = retrieveLockId(lockfilename); //throw FileError, ErrorNotExisting const std::shared_ptr<SharedDirLock>& activeLock = findActive(lockId); //returns null-lock if not found if (activeLock) @@ -544,11 +546,11 @@ public: return activeLock; } } - catch (const ErrorNotExisting&) {} //let other FileError(s) propagate! + catch (...) {} //catch everything, let SharedDirLock constructor deal with errors, e.g. 0-sized/corrupted lock file //not yet in buffer, so create a new directory lock - std::shared_ptr<SharedDirLock> newLock(new SharedDirLock(lockfilename, callback)); //throw (FileError) - const std::string newLockId = retrieveLockId(lockfilename); //throw (FileError, ErrorNotExisting) + std::shared_ptr<SharedDirLock> newLock(new SharedDirLock(lockfilename, callback)); //throw FileError + const std::string newLockId = retrieveLockId(lockfilename); //throw FileError, ErrorNotExisting //update registry fileToUuid[lockfilename] = newLockId; //throw() @@ -579,7 +581,7 @@ private: }; -DirLock::DirLock(const Zstring& lockfilename, DirLockCallback* callback) //throw (FileError) +DirLock::DirLock(const Zstring& lockfilename, DirLockCallback* callback) //throw FileError { #ifdef FFS_WIN std::vector<wchar_t> volName(std::max(lockfilename.size(), static_cast<size_t>(10000))); |