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afflib_os.cpp
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afflib_os.cpp
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/*
* afflib_os.cpp:
*
* The OS-specific features of AFFLIB
*
* This file is a work of a US government employee and as such is in the Public domain.
* Simson L. Garfinkel, March 12, 2012
*/
#include "affconfig.h"
#include "afflib.h"
#include "afflib_i.h"
#ifdef HAVE_SYS_PARAM_H
#include <sys/param.h>
#endif
#if defined(__FreeBSD_version) && __FreeBSD_version<500000
#undef HAVE_SYS_DISK_H
#endif
#if defined(HAVE_SYS_DISK_H)
#include <sys/disk.h>
#endif
#ifdef HAVE_LINUX_FS_H
#include <linux/fs.h>
#endif
#ifdef HAVE_SYS_IOCTL_H
#include <sys/ioctl.h> // needed for Linux
#endif
/****************************************************************
*** Extra code for Windows...
****************************************************************/
/* No longer needed with VC2008 */
#if 0
#if defined(WIN32) and !defined(__MINGW_H)
#pragma warning(disable: 4996)
int64 ftello(FILE *stream)
{
fpos_t pos;
if(fgetpos(stream,&pos) != 0){
return -1;
}
return pos;
}
int fseeko(FILE *stream,int64 offset,int whence)
{
switch(whence){
case SEEK_SET:
break; // jump down to fsetpos()
case SEEK_CUR:
offset += ftello(stream);
break;
case SEEK_END:
fseek(stream,0L,SEEK_END); // go to the end; hope this works for big files
offset = ftello(stream) - offset;
break;
default:
return -1;
}
return fsetpos(stream,&offset);
}
#endif
#endif
/****************************************************************/
/* af_figure_media():
*
* This is a function that returns, for the file handle of an open
* device, the sector_size, total_sectors, and maximum number of
* blocks that can be read at a time (or 0 if there is no max). There
* is a generic implementation at the bottom, and operating-specific
* versions above.
*/
int af_figure_media(int fd,struct af_figure_media_buf *afb)
{
memset(afb,0,sizeof(*afb));
afb->version = 1;
#ifdef __APPLE__
#define MEDIA_FIGURED
if(ioctl(fd,DKIOCGETBLOCKSIZE,&afb->sector_size)){
afb->sector_size = 512; // assume 512
}
if(ioctl(fd,DKIOCGETBLOCKCOUNT,&afb->total_sectors)){
afb->total_sectors=0; // seeking not allowed on stdin
}
if(ioctl(fd,DKIOCGETMAXBLOCKCOUNTREAD,&afb->max_read_blocks)){
afb->max_read_blocks = 0; // read all you want
}
#endif
#if defined(__FreeBSD__) && defined(DIOCGSECTORSIZE)
#define MEDIA_FIGURED
if(ioctl(fd,DIOCGSECTORSIZE,&afb->sector_size)){
afb->sector_size = 512; // can't figure it out; go with the default
}
off_t inbytes=0;
if(ioctl(fd,DIOCGMEDIASIZE,&inbytes)){
afb->total_sectors = 0;
}
if(inbytes % afb->sector_size != 0){
fprintf(stderr,"ioctl(DIOCGSECTORSIZE) returns %d bytes\n", afb->sector_size);
fprintf(stderr,"ioctl(DIOCGMEDIASIZE) returns %d bytes\n", inbytes);
fprintf(stderr,"which is not an even number of sectors.\n");
return -1;
}
afb->total_sectors = inbytes / afb->sector_size;
afb->max_read_blocks = 0;
#endif
#ifdef linux
#define MEDIA_FIGURED
/* With Linux, we figure out how many bytes there are and get sector size
* from a #define
*/
afb->sector_size = BLOCK_SIZE;
#ifdef BLKGETSIZE64
uint64_t total_bytes=0;
if(ioctl(fd,BLKGETSIZE64,&total_bytes)){
total_bytes = 0;
}
#else
int total_bytes=0;
if(ioctl(fd,BLKGETSIZE,&total_bytes)){
total_bytes = 0;
}
#endif
afb->total_sectors = total_bytes / afb->sector_size;
afb->max_read_blocks = 0;
#endif
#ifndef MEDIA_FIGURED
/* Unknown OS type. Try our best-effort guess,
*/
#ifdef BLOCK_SIZE
afb->sector_size = BLOCK_SIZE; // it's a good guess
#else
afb->sector_size = 512; // it's a good guess
#endif
/* Try seeking to the end of fd and ask where we are! */
off_t start_pos = lseek(fd,0,SEEK_CUR); // find where we are
off_t end_of_file = lseek(fd,0,SEEK_END);
if(end_of_file==-1){
end_of_file = 0; // can't figure it.
}
lseek(fd,start_pos,SEEK_SET); // go back to the starting position
afb->total_sectors = end_of_file / afb->sector_size;
afb->max_read_blocks = 0;
#endif
return 0;
}

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