minix/lib/libminlib/fslib.c
2012-03-25 21:58:27 +02:00

190 lines
7 KiB
C

/* fslib.c - routines needed by fs and fs utilities */
#include <minix/config.h> /* for unused stuff in <minix/type.h> :-( */
#include <limits.h>
#include <dirent.h>
#include <sys/types.h>
#include <minix/const.h>
#include <minix/type.h> /* for unshort :-( */
#include "mfs/const.h" /* depends of -I flag in Makefile */
#include "mfs/type.h" /* ditto */
#include "mfs/inode.h" /* ditto */
#include "mfs/super.h"
#include <minix/fslib.h>
/* The next routine is copied from fsck.c and mkfs.c... (Re)define some
* things for consistency. Some things should be done better.
*/
/* Convert from bit count to a block count. The usual expression
*
* (nr_bits + (1 << BITMAPSHIFT) - 1) >> BITMAPSHIFT
*
* doesn't work because of overflow.
*
* Other overflow bugs, such as the expression for N_ILIST overflowing when
* s_inodes is just over V*_INODES_PER_BLOCK less than the maximum+1, are not
* fixed yet, because that number of inodes is silly.
*/
/* The above comment doesn't all apply now bit_t is long. Overflow is now
* unlikely, but negative bit counts are now possible (though unlikely)
* and give silly results.
*/
int bitmapsize(nr_bits, block_size)
bit_t nr_bits;
int block_size;
{
int nr_blocks;
nr_blocks = (int) (nr_bits / FS_BITS_PER_BLOCK(block_size));
if (((bit_t) nr_blocks * FS_BITS_PER_BLOCK(block_size)) < nr_bits) ++nr_blocks;
return(nr_blocks);
}
/*===========================================================================*
* conv2 *
*===========================================================================*/
unsigned conv2(norm, w)
int norm; /* TRUE if no swap, FALSE for byte swap */
int w; /* promotion of 16-bit word to be swapped */
{
/* Possibly swap a 16-bit word between 8086 and 68000 byte order. */
if (norm) return( (unsigned) w & 0xFFFF);
return( ((w&BYTE) << 8) | ( (w>>8) & BYTE));
}
/*===========================================================================*
* conv4 *
*===========================================================================*/
long conv4(norm, x)
int norm; /* TRUE if no swap, FALSE for byte swap */
long x; /* 32-bit long to be byte swapped */
{
/* Possibly swap a 32-bit long between 8086 and 68000 byte order. */
unsigned lo, hi;
long l;
if (norm) return(x); /* byte order was already ok */
lo = conv2(FALSE, (int) x & 0xFFFF); /* low-order half, byte swapped */
hi = conv2(FALSE, (int) (x>>16) & 0xFFFF); /* high-order half, swapped */
l = ( (long) lo <<16) | hi;
return(l);
}
/*===========================================================================*
* conv_inode *
*===========================================================================*/
void conv_inode(rip, dip, dip2, rw_flag, magic)
register struct inode *rip; /* pointer to the in-core inode struct */
register d1_inode *dip; /* pointer to the V1 on-disk inode struct */
register d2_inode *dip2; /* pointer to the V2 on-disk inode struct */
int rw_flag; /* READING or WRITING */
int magic; /* magic number of file system */
{
/* Copy the inode from the disk block to the in-core table or vice versa.
* If the fourth parameter below is FALSE, the bytes are swapped.
*/
switch (magic) {
case SUPER_MAGIC: old_icopy(rip, dip, rw_flag, TRUE); break;
case SUPER_REV: old_icopy(rip, dip, rw_flag, FALSE); break;
case SUPER_V3:
case SUPER_V2: new_icopy(rip, dip2, rw_flag, TRUE); break;
case SUPER_V2_REV: new_icopy(rip, dip2, rw_flag, FALSE); break;
}
}
/*===========================================================================*
* old_icopy *
*===========================================================================*/
void old_icopy(rip, dip, direction, norm)
register struct inode *rip; /* pointer to the in-core inode struct */
register d1_inode *dip; /* pointer to the d1_inode inode struct */
int direction; /* READING (from disk) or WRITING (to disk) */
int norm; /* TRUE = do not swap bytes; FALSE = swap */
{
/* 4 different on-disk inode layouts are supported, one for each combination
* of V1.x/V2.x * bytes-swapped/not-swapped. When an inode is read or written
* this routine handles the conversions so that the information in the inode
* table is independent of the disk structure from which the inode came.
* The old_icopy routine copies to and from V1 disks.
*/
int i;
if (direction == READING) {
/* Copy V1.x inode to the in-core table, swapping bytes if need be. */
rip->i_mode = conv2(norm, dip->d1_mode);
rip->i_uid = conv2(norm,dip->d1_uid );
rip->i_size = conv4(norm,dip->d1_size);
rip->i_mtime = conv4(norm,dip->d1_mtime);
rip->i_atime = 0;
rip->i_ctime = 0;
rip->i_nlinks = (nlink_t) dip->d1_nlinks; /* 1 char */
rip->i_gid = (gid_t) dip->d1_gid; /* 1 char */
rip->i_ndzones = V1_NR_DZONES;
rip->i_nindirs = V1_INDIRECTS;
for (i = 0; i < V1_NR_TZONES; i++)
rip->i_zone[i] = conv2(norm, (int) dip->d1_zone[i]);
} else {
/* Copying V1.x inode to disk from the in-core table. */
dip->d1_mode = conv2(norm,rip->i_mode);
dip->d1_uid = conv2(norm,rip->i_uid );
dip->d1_size = conv4(norm,rip->i_size);
dip->d1_mtime = conv4(norm,rip->i_mtime);
dip->d1_nlinks = (nlink_t) rip->i_nlinks; /* 1 char */
dip->d1_gid = (gid_t) rip->i_gid; /* 1 char */
for (i = 0; i < V1_NR_TZONES; i++)
dip->d1_zone[i] = conv2(norm, (int) rip->i_zone[i]);
}
}
/*===========================================================================*
* new_icopy *
*===========================================================================*/
void new_icopy(rip, dip, direction, norm)
register struct inode *rip; /* pointer to the in-core inode struct */
register d2_inode *dip; /* pointer to the d2_inode struct */
int direction; /* READING (from disk) or WRITING (to disk) */
int norm; /* TRUE = do not swap bytes; FALSE = swap */
{
/* Same as old_icopy, but to/from V2 disk layout. */
int i;
if (direction == READING) {
/* Copy V2.x inode to the in-core table, swapping bytes if need be. */
rip->i_mode = conv2(norm,dip->d2_mode);
rip->i_uid = conv4(norm,dip->d2_uid );
rip->i_nlinks = conv2(norm,(int) dip->d2_nlinks);
rip->i_gid = conv4(norm,(int) dip->d2_gid );
rip->i_size = conv4(norm,dip->d2_size);
rip->i_atime = conv4(norm,dip->d2_atime);
rip->i_ctime = conv4(norm,dip->d2_ctime);
rip->i_mtime = conv4(norm,dip->d2_mtime);
rip->i_ndzones = V2_NR_DZONES;
rip->i_nindirs = V2_INDIRECTS(rip->i_sp->s_block_size);
for (i = 0; i < V2_NR_TZONES; i++)
rip->i_zone[i] = conv4(norm, (long) dip->d2_zone[i]);
} else {
/* Copying V2.x inode to disk from the in-core table. */
dip->d2_mode = conv2(norm,rip->i_mode);
dip->d2_uid = conv4(norm,rip->i_uid );
dip->d2_nlinks = conv2(norm,rip->i_nlinks);
dip->d2_gid = conv4(norm,rip->i_gid );
dip->d2_size = conv4(norm,rip->i_size);
dip->d2_atime = conv4(norm,rip->i_atime);
dip->d2_ctime = conv4(norm,rip->i_ctime);
dip->d2_mtime = conv4(norm,rip->i_mtime);
for (i = 0; i < V2_NR_TZONES; i++)
dip->d2_zone[i] = conv4(norm, (long) rip->i_zone[i]);
}
}