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/*************************************************************** -*- c++ -*-
* Copyright (c) 2003,2004 by Marcel Wiesweg *
* *
* This program is free software; you can redistribute it and/or modify *
* it under the terms of the GNU General Public License as published by *
* the Free Software Foundation; either version 2 of the License, or *
* (at your option) any later version. *
* *
***************************************************************************/
#include <sys/vfs.h>
#include "legacystorage.h"
LegacyStorage::LegacyStorage(int maxMB)
: fsBlockSize(1), pageBytes(TELETEXT_PAGESIZE)
{
initMaxStorage(maxMB);
}
LegacyStorage::~LegacyStorage() {
}
/*
static inline int FilesForMegabytes(double MB, int blocksize) {
double pageBytes;
if (TELETEXT_PAGESIZE<=blocksize)
pageBytes=blocksize;
else
pageBytes=((TELETEXT_PAGESIZE/blocksize)+1)*blocksize;
//reserve 10% for directories
return (int)( (1024.0 * 1024.0 * (MB-MB*0.1)) / pageBytes );
}*/
int LegacyStorage::actualFileSize(int netFileSize) {
if (netFileSize<=0)
return 0;
if (netFileSize<=fsBlockSize)
return fsBlockSize;
else
return ((netFileSize/fsBlockSize)+1)*fsBlockSize;
}
//max==0 means unlimited, max==-1 means a reasonable default value shall be calculated
void LegacyStorage::initMaxStorage(int maxMB) {
struct statfs fs;
if (statfs(getRootDir(), &fs)!=0) {
esyslog("OSD-Teletext: Error statfs'ing root directory \"%s\": %s, cache size uncontrolled", getRootDir(), strerror(errno));
return;
}
fsBlockSize=fs.f_bsize;
pageBytes=actualFileSize(TELETEXT_PAGESIZE);
if (maxMB>=0) {
if (maxMB<3) {
esyslog("OSD-Teletext: Request to use at most %d MB for caching. This is not enough, using 3 MB", maxMB);
maxMB=3;
}
maxBytes=MEGABYTE(maxMB);
} else if (maxMB==-1) {
//calculate a default value
double blocksPerMeg = 1024.0 * 1024.0 / fs.f_bsize;
double capacityMB=fs.f_blocks / blocksPerMeg;
double freeMB=(fs.f_bavail / blocksPerMeg);
if (capacityMB<=50 || freeMB<50) {
//small (<=50MB) filesystems as root dir are assumed to be dedicated for use as a teletext cache
//for others, the maximum default size is set to 50 MB
maxBytes=MEGABYTE((int)freeMB);
//maxPages= FilesForMegabytes(freeMB, fs.f_bsize);
if (freeMB<3.0) {
esyslog("OSD-Teletext: Less than %.1f MB free on filesystem of root directory \"%s\"!", freeMB, getRootDir());
maxBytes=MEGABYTE(3);
}
} else {
//the maximum default size is set to 50 MB
maxBytes=MEGABYTE(50);
}
//printf("Set maxBytes to %ld, %.2f %.2f\n", maxBytes, capacityMB, freeMB);
}
}
void LegacyStorage::cleanUp() {
byteCount -= Storage::doCleanUp();
}
void LegacyStorage::registerFile(PageID page) {
//pageBytes is already effective size
if ( maxBytes && (byteCount+=pageBytes)>maxBytes )
freeSpace();
}
StorageHandle LegacyStorage::openForReading(PageID page, bool countAsAccess) {
//the countAsAccess argument was intended for use in a LRU cache, currently unused
char filename[PATH_MAX];
getFilename(filename, sizeof(filename), page);
StorageHandle ret=(StorageHandle)open(filename, O_RDONLY);
return ret;
}
StorageHandle LegacyStorage::openForWriting(PageID page) {
static bool wroteError=false;
char filename[PATH_MAX];
getFilename(filename, sizeof(filename), page);
bool existed=exists(filename);
//first try
StorageHandle fd=(StorageHandle)open(filename, O_WRONLY | O_CREAT | O_TRUNC, S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
if (fd) {
if (!existed)
registerFile(page);
return fd;
}
//no space on disk? make some space available
if (errno == ENOSPC)
freeSpace();
//second try
fd=(StorageHandle)open(filename, O_WRONLY | O_CREAT | O_TRUNC, S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
if (!fd && !wroteError) {
//report error to syslog - once!
wroteError=true;
esyslog("OSD-Teletext: Error opening teletext file %s: %s", filename, strerror(errno));
}
//make sure newly created files are counted
if (fd && !existed)
registerFile(page);
return fd;
}
ssize_t LegacyStorage::write(const void *ptr, size_t size, StorageHandle stream) {
ssize_t written;
if (!(written=::write((int)stream, ptr, size)) ) {
switch (errno) {
case ENOSPC:
freeSpace();
return ::write((int)stream, ptr, size);
case EINTR:
esyslog("OSD-Teletext: EINTR while writing. Please contact the author and tell him this happened.");
break;
default:
break;
}
}
return written;
}
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