161 lines
3.5 KiB
C
161 lines
3.5 KiB
C
/* $NetBSD: readufs_ffs.c,v 1.6 2004/03/21 12:46:57 dsl Exp $ */
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/* from Id: readufs_ffs.c,v 1.6 2003/04/08 09:19:32 itohy Exp */
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/*
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* FS specific support for 4.2BSD Fast Filesystem
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*
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* Written in 1999, 2002, 2003 by ITOH Yasufumi (itohy@NetBSD.org).
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* Public domain.
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*
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* Intended to be used for boot programs (first stage).
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* DON'T ADD ANY FANCY FEATURE. THIS SHALL BE COMPACT.
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*/
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#include "readufs.h"
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#include <ufs/ffs/fs.h>
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static int get_ffs_inode __P((ino_t ino, union ufs_dinode *dibuf));
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#define fsi (*ufsinfo)
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#define fsi_ffs fsi.fs_u.u_ffs
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/*
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* Read and check superblock.
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* If it is an FFS, save information from the superblock.
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*/
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int
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try_ffs()
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{
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union {
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struct fs sblk;
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unsigned char pad[SBLOCKSIZE];
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} buf;
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struct ufs_info *ufsinfo = &ufs_info;
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static const int sblocs[] = SBLOCKSEARCH;
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const int *sbl;
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int magic;
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#ifdef DEBUG_WITH_STDIO
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printf("trying FFS\n");
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#endif
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/* read FFS superblock */
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for (sbl = sblocs; ; sbl++) {
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if (*sbl == -1)
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return 1;
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RAW_READ(&buf, (daddr_t) btodb(*sbl), SBLOCKSIZE);
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magic = buf.sblk.fs_magic;
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#ifdef DEBUG_WITH_STDIO
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printf("FFS: sblk: pos %d magic 0x%x\n", btodb(*sbl), magic);
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#endif
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if (buf.sblk.fs_old_flags & FS_FLAGS_UPDATED) {
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if (*sbl != buf.sblk.fs_sblockloc)
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/* must be an alternate suberblock */
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continue;
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} else {
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if (*sbl == SBLOCK_UFS2)
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/* might be an alternate suberblock */
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continue;
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}
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#ifdef USE_UFS1
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if (magic == FS_UFS1_MAGIC)
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break;
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#endif
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#ifdef USE_UFS2
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if (magic == FS_UFS2_MAGIC) {
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#ifdef USE_UFS1
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fsi.ufstype = UFSTYPE_UFS2;
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#endif
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break;
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}
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#endif
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}
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/*
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* XXX <ufs/ffs/fs.h> always uses fs_magic
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* (UFS1 only or UFS2 only is impossible)
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*/
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fsi_ffs.magic = magic;
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#ifdef DEBUG_WITH_STDIO
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printf("FFS: detected UFS%d format\n", (magic == FS_UFS2_MAGIC) + 1);
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#endif
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/* This partition looks like an FFS. */
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fsi.fstype = UFSTYPE_FFS;
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fsi.get_inode = get_ffs_inode;
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/* Get information from the superblock. */
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fsi.bsize = buf.sblk.fs_bsize;
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fsi.fsbtodb = buf.sblk.fs_fsbtodb;
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fsi.nindir = buf.sblk.fs_nindir;
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fsi_ffs.iblkno = buf.sblk.fs_iblkno;
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fsi_ffs.old_cgoffset = buf.sblk.fs_old_cgoffset;
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fsi_ffs.old_cgmask = buf.sblk.fs_old_cgmask;
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fsi_ffs.fragshift = buf.sblk.fs_fragshift;
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fsi_ffs.inopb = buf.sblk.fs_inopb;
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fsi_ffs.ipg = buf.sblk.fs_ipg;
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fsi_ffs.fpg = buf.sblk.fs_fpg;
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return 0;
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}
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/* for inode macros */
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#define fs_ipg fs_u.u_ffs.ipg
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#define fs_iblkno fs_u.u_ffs.iblkno
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#define fs_old_cgoffset fs_u.u_ffs.old_cgoffset
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#define fs_old_cgmask fs_u.u_ffs.old_cgmask
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#define fs_fpg fs_u.u_ffs.fpg
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#define fs_magic fs_u.u_ffs.magic
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#define fs_inopb fs_u.u_ffs.inopb
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#define fs_fragshift fs_u.u_ffs.fragshift
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#define fs_fsbtodb fsbtodb
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/*
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* Get inode from disk.
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*/
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static int
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get_ffs_inode(ino, dibuf)
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ino_t ino;
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union ufs_dinode *dibuf;
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{
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struct ufs_info *ufsinfo = &ufs_info;
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union ufs_dinode *buf = alloca((size_t) fsi.bsize);
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union ufs_dinode *di;
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unsigned ioff;
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RAW_READ(buf, fsbtodb(&fsi, ino_to_fsba(&fsi, ino)),
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(size_t) fsi.bsize);
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ioff = ino_to_fsbo(&fsi, ino);
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#if defined(USE_UFS1) && defined(USE_UFS2)
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if (ufsinfo->ufstype == UFSTYPE_UFS1)
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di = (void *) &(&buf->di1)[ioff];
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else {
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di = (void *) &(&buf->di2)[ioff];
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/* XXX for DI_SIZE() macro */
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di->di1.di_size = di->di2.di_size;
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}
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#else
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di = &buf[ioff];
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#endif
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#ifdef DEBUG_WITH_STDIO
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printf("FFS: dinode(%d): mode 0%o, nlink %d, size %u\n",
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ino, di->di_common.di_mode, di->di_common.di_nlink,
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(unsigned) DI_SIZE(di));
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#endif
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if (di->di_common.di_mode == 0)
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return 1; /* unused inode (file is not found) */
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*dibuf = *di;
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return 0;
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}
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