kdecore Library API Documentation

ksavefile.cpp

00001 /*
00002   This file is part of the KDE libraries
00003   Copyright (c) 1999 Waldo Bastian <bastian@kde.org>
00004 
00005   This library is free software; you can redistribute it and/or
00006   modify it under the terms of the GNU Library General Public
00007   License version 2 as published by the Free Software Foundation.
00008 
00009   This library is distributed in the hope that it will be useful,
00010   but WITHOUT ANY WARRANTY; without even the implied warranty of
00011   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00012   Library General Public License for more details.
00013 
00014   You should have received a copy of the GNU Library General Public License
00015   along with this library; see the file COPYING.LIB.  If not, write to
00016   the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
00017   Boston, MA 02111-1307, USA.
00018 */
00019 
00020 #include <config.h>
00021 
00022 #include <sys/types.h>
00023 
00024 #ifdef HAVE_SYS_STAT_H
00025 #include <sys/stat.h>
00026 #endif
00027 
00028 #include <unistd.h>
00029 #include <fcntl.h>
00030 
00031 #ifdef HAVE_TEST
00032 #include <test.h>
00033 #endif
00034 
00035 #include <qdatetime.h>
00036 #include <qdir.h>
00037 
00038 #include "kapplication.h"
00039 #include "ksavefile.h"
00040 
00041 KSaveFile::KSaveFile(const QString &filename, int mode)
00042  : mTempFile(true)
00043 {
00044 
00045    // follow symbolic link, if any
00046    QString real_filename = filename;
00047 
00048    QFileInfo file_info(real_filename);
00049    int c=0;
00050    while(file_info.isSymLink() && ++c<6) {
00051      real_filename = file_info.readLink();
00052       file_info.setFile( real_filename );
00053    }
00054 
00055    // we only check here if the directory can be written to
00056    // the actual filename isn't written to, but replaced later
00057    // with the contents of our tempfile
00058    if (!checkAccess(real_filename, W_OK))
00059    {
00060       mTempFile.setError(EACCES);
00061       return;
00062    }
00063 
00064    if (mTempFile.create(real_filename, QString::fromLatin1(".new"), mode))
00065    {
00066       mFileName = real_filename; // Set filename upon success
00067 
00068       // if we're overwriting an existing file, ensure temp file's
00069       // permissions are the same as existing file so the existing
00070       // file's permissions are preserved
00071       struct stat stat_buf;
00072       if ((stat(QFile::encodeName(real_filename), &stat_buf)==0)
00073           && (stat_buf.st_uid == getuid())
00074           && (stat_buf.st_gid == getgid()))
00075       {
00076          fchmod(mTempFile.handle() , stat_buf.st_mode);
00077       }
00078    }
00079    return;
00080 }
00081 
00082 KSaveFile::~KSaveFile()
00083 {
00084    close();
00085 }
00086 
00087 QString
00088 KSaveFile::name() const
00089 {
00090    return mFileName;
00091 }
00092 
00093 void
00094 KSaveFile::abort()
00095 {
00096    mTempFile.unlink();
00097    mTempFile.close();
00098 }
00099 
00100 bool
00101 KSaveFile::close()
00102 {
00103    if (mTempFile.name().isEmpty())
00104       return false; // Save was aborted already
00105    if (mTempFile.close())
00106    {
00107       QDir dir;
00108       bool result = dir.rename( mTempFile.name(), mFileName);
00109       if ( result )
00110       {
00111          return true; // Success!
00112       }
00113       mTempFile.setError(errno);
00114    }
00115 
00116    // Something went wrong, make sure to delete the interim file.
00117    mTempFile.unlink();
00118    return false;
00119 }
00120 
00121 static int
00122 write_all(int fd, const char *buf, size_t len)
00123 {
00124    while (len > 0)
00125    {
00126       int written = write(fd, buf, len);
00127       if (written < 0)
00128       {
00129           if (errno == EINTR)
00130              continue;
00131           return -1;
00132       }
00133       buf += written;
00134       len -= written;
00135    }
00136    return 0;
00137 }
00138 
00139 bool KSaveFile::backupFile( const QString& qFilename, const QString& backupDir,
00140                             const QString& backupExtension)
00141 {
00142    QCString cFilename = QFile::encodeName(qFilename);
00143    const char *filename = cFilename.data();
00144 
00145    int fd = open( filename, O_RDONLY);
00146    if (fd < 0)
00147       return false;
00148 
00149    struct stat buff;
00150    if ( fstat( fd, &buff) < 0 )
00151    {
00152       ::close( fd );
00153       return false;
00154    }
00155 
00156    QCString cBackup;
00157    if ( backupDir.isEmpty() )
00158        cBackup = cFilename;
00159    else
00160    {
00161        QCString nameOnly;
00162        int slash = cFilename.findRev('/');
00163        if (slash < 0)
00164        nameOnly = cFilename;
00165        else
00166        nameOnly = cFilename.mid(slash + 1);
00167        cBackup = QFile::encodeName(backupDir);
00168        if ( backupDir[backupDir.length()-1] != '/' )
00169            cBackup += '/';
00170        cBackup += nameOnly;
00171    }
00172    cBackup += QFile::encodeName(backupExtension);
00173    const char *backup = cBackup.data();
00174    int permissions = buff.st_mode & 07777;
00175 
00176    if ( stat( backup, &buff) == 0)
00177    {
00178       if ( unlink( backup ) != 0 )
00179       {
00180          ::close(fd);
00181          return false;
00182       }
00183    }
00184 
00185    mode_t old_umask = umask(0);
00186    int fd2 = open( backup, O_WRONLY | O_CREAT | O_EXCL, permissions | S_IWUSR);
00187    umask(old_umask);
00188 
00189    if ( fd2 < 0 )
00190    {
00191       ::close(fd);
00192       return false;
00193    }
00194 
00195     char buffer[ 32*1024 ];
00196 
00197     while( 1 )
00198     {
00199        int n = ::read( fd, buffer, 32*1024 );
00200        if (n == -1)
00201        {
00202           if (errno == EINTR)
00203               continue;
00204           ::close(fd);
00205           ::close(fd2);
00206           return false;
00207        }
00208        if (n == 0)
00209           break; // Finished
00210 
00211        if (write_all( fd2, buffer, n))
00212        {
00213           ::close(fd);
00214           ::close(fd2);
00215           return false;
00216        }
00217     }
00218 
00219     ::close( fd );
00220 
00221     if (::close(fd2))
00222         return false;
00223     return true;
00224 }
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This file is part of the documentation for kdecore Library Version 3.2.1.
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