Add ext2fs support to the loader.
This commit is contained in:
jlemon
parent
13995ed718
commit
0340a88f8a
903
lib/libstand/ext2fs.c
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903
lib/libstand/ext2fs.c
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@ -0,0 +1,903 @@
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/*-
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* Copyright (c) 1999,2000 Jonathan Lemon <jlemon@freebsd.org>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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/*-
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* Copyright (c) 1993
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* The Regents of the University of California. All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* The Mach Operating System project at Carnegie-Mellon University.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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*
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* Copyright (c) 1990, 1991 Carnegie Mellon University
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* All Rights Reserved.
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*
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* Author: David Golub
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*
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* Permission to use, copy, modify and distribute this software and its
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* documentation is hereby granted, provided that both the copyright
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* notice and this permission notice appear in all copies of the
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* software, derivative works or modified versions, and any portions
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* thereof, and that both notices appear in supporting documentation.
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*
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* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
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* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
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* ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
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*
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* Carnegie Mellon requests users of this software to return to
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*
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* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
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* School of Computer Science
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* Carnegie Mellon University
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* Pittsburgh PA 15213-3890
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*
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* any improvements or extensions that they make and grant Carnegie the
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* rights to redistribute these changes.
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*/
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#include <sys/param.h>
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#include <sys/time.h>
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#include "stand.h"
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#include "string.h"
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static int ext2fs_open(const char *path, struct open_file *f);
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static int ext2fs_close(struct open_file *f);
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static int ext2fs_read(struct open_file *f, void *buf,
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size_t size, size_t *resid);
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static off_t ext2fs_seek(struct open_file *f, off_t offset, int where);
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static int ext2fs_stat(struct open_file *f, struct stat *sb);
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static int ext2fs_readdir(struct open_file *f, struct dirent *d);
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static int dtmap[] = { DT_UNKNOWN, DT_REG, DT_DIR, DT_CHR,
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DT_BLK, DT_FIFO, DT_SOCK, DT_LNK };
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#define EXTFTODT(x) (x) > sizeof(dtmap) / sizeof(dtmap[0]) ? \
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DT_UNKNOWN : dtmap[x]
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struct fs_ops ext2fs_fsops = {
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"ext2fs",
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ext2fs_open,
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ext2fs_close,
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ext2fs_read,
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null_write,
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ext2fs_seek,
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ext2fs_stat,
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ext2fs_readdir
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};
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#define EXT2_SBSIZE 1024
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#define EXT2_SBLOCK (1024 / DEV_BSIZE) /* block offset of superblock */
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#define EXT2_MAGIC 0xef53
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#define EXT2_ROOTINO 2
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#define EXT2_REV0 0 /* original revision of ext2 */
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#define EXT2_R0_ISIZE 128 /* inode size */
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#define EXT2_R0_FIRSTINO 11 /* first inode */
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#define EXT2_MINBSHIFT 10 /* mininum block shift */
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#define EXT2_MINFSHIFT 10 /* mininum frag shift */
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#define NDADDR 12 /* # of direct blocks */
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#define NIADDR 3 /* # of indirect blocks */
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/*
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* file system block to disk address
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*/
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#define fsb_to_db(fs, blk) ((blk) << (fs)->fs_fsbtodb)
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/*
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* inode to block group offset
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* inode to block group
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* inode to disk address
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* inode to block offset
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*/
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#define ino_to_bgo(fs, ino) (((ino) - 1) % (fs)->fs_ipg)
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#define ino_to_bg(fs, ino) (((ino) - 1) / (fs)->fs_ipg)
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#define ino_to_db(fs, bg, ino) \
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fsb_to_db(fs, ((bg)[ino_to_bg(fs, ino)].bg_inotbl + \
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ino_to_bgo(fs, ino) / (fs)->fs_ipb))
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#define ino_to_bo(fs, ino) (ino_to_bgo(fs, ino) % (fs)->fs_ipb)
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#define nindir(fs) \
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((fs)->fs_bsize / sizeof(u_int32_t))
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#define lblkno(fs, loc) /* loc / bsize */ \
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((loc) >> (fs)->fs_bshift)
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#define smalllblktosize(fs, blk) /* blk * bsize */ \
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((blk) << (fs)->fs_bshift)
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#define blkoff(fs, loc) /* loc % bsize */ \
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((loc) & (fs)->fs_bmask)
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#define fragroundup(fs, size) /* roundup(size, fsize) */ \
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(((size) + (fs)->fs_fmask) & ~(fs)->fs_fmask)
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#define dblksize(fs, dip, lbn) \
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(((lbn) >= NDADDR || (dip)->di_size >= smalllblktosize(fs, (lbn) + 1)) \
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? (fs)->fs_bsize \
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: (fragroundup(fs, blkoff(fs, (dip)->di_size))))
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/*
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* superblock describing ext2fs
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*/
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struct ext2fs_disk {
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u_int32_t fd_inodes; /* # of inodes */
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u_int32_t fd_blocks; /* # of blocks */
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u_int32_t fd_resblk; /* # of reserved blocks */
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u_int32_t fd_freeblk; /* # of free blocks */
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u_int32_t fd_freeino; /* # of free inodes */
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u_int32_t fd_firstblk; /* first data block */
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u_int32_t fd_bsize; /* block size */
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u_int32_t fd_fsize; /* frag size */
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u_int32_t fd_bpg; /* blocks per group */
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u_int32_t fd_fpg; /* frags per group */
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u_int32_t fd_ipg; /* inodes per group */
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u_int32_t fd_mtime; /* mount time */
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u_int32_t fd_wtime; /* write time */
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u_int16_t fd_mount; /* # of mounts */
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int16_t fd_maxmount; /* max # of mounts */
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u_int16_t fd_magic; /* magic number */
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u_int16_t fd_state; /* state */
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u_int16_t fd_eflag; /* error flags */
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u_int16_t fd_mnrrev; /* minor revision */
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u_int32_t fd_lastchk; /* last check */
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u_int32_t fd_chkintvl; /* maximum check interval */
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u_int32_t fd_os; /* os */
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u_int32_t fd_revision; /* revision */
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u_int16_t fd_uid; /* uid for reserved blocks */
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u_int16_t fd_gid; /* gid for reserved blocks */
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u_int32_t fd_firstino; /* first non-reserved inode */
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u_int16_t fd_isize; /* inode size */
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u_int16_t fd_nblkgrp; /* block group # of superblock */
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u_int32_t fd_fcompat; /* compatible features */
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u_int32_t fd_fincompat; /* incompatible features */
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u_int32_t fd_frocompat; /* read-only compatabilties */
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u_int8_t fd_uuid[16]; /* volume uuid */
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char fd_volname[16]; /* volume name */
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char fd_fsmnt[64]; /* name last mounted on */
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u_int32_t fd_bitmap; /* compression bitmap */
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u_int8_t fd_nblkpa; /* # of blocks to preallocate */
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u_int8_t fd_ndblkpa; /* # of dir blocks to preallocate */
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};
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struct ext2fs_core {
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int fc_bsize; /* block size */
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int fc_bshift; /* block shift amount */
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int fc_bmask; /* block mask */
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int fc_fsize; /* frag size */
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int fc_fshift; /* frag shift amount */
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int fc_fmask; /* frag mask */
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int fc_isize; /* inode size */
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int fc_imask; /* inode mask */
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int fc_firstino; /* first non-reserved inode */
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int fc_ipb; /* inodes per block */
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int fc_fsbtodb; /* fsb to ds shift */
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};
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struct ext2fs {
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struct ext2fs_disk fs_fd;
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char fs_pad[EXT2_SBSIZE - sizeof(struct ext2fs_disk)];
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struct ext2fs_core fs_fc;
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#define fs_magic fs_fd.fd_magic
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#define fs_revision fs_fd.fd_revision
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#define fs_blocks fs_fd.fd_blocks
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#define fs_firstblk fs_fd.fd_firstblk
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#define fs_bpg fs_fd.fd_bpg
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#define fs_ipg fs_fd.fd_ipg
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#define fs_bsize fs_fc.fc_bsize
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#define fs_bshift fs_fc.fc_bshift
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#define fs_bmask fs_fc.fc_bmask
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#define fs_fsize fs_fc.fc_fsize
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#define fs_fshift fs_fc.fc_fshift
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#define fs_fmask fs_fc.fc_fmask
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#define fs_isize fs_fc.fc_isize
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#define fs_imask fs_fc.fc_imask
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#define fs_firstino fs_fc.fc_firstino
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#define fs_ipb fs_fc.fc_ipb
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#define fs_fsbtodb fs_fc.fc_fsbtodb
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};
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struct ext2blkgrp {
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u_int32_t bg_blkmap; /* block bitmap */
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u_int32_t bg_inomap; /* inode bitmap */
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u_int32_t bg_inotbl; /* inode table */
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u_int16_t bg_nfblk; /* # of free blocks */
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u_int16_t bg_nfino; /* # of free inodes */
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u_int16_t bg_ndirs; /* # of dirs */
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char bg_pad[14];
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};
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struct ext2dinode {
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u_int16_t di_mode; /* mode */
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u_int16_t di_uid; /* uid */
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u_int32_t di_size; /* byte size */
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u_int32_t di_atime; /* access time */
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u_int32_t di_ctime; /* creation time */
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u_int32_t di_mtime; /* modification time */
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u_int32_t di_dtime; /* deletion time */
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u_int16_t di_gid; /* gid */
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u_int16_t di_nlink; /* link count */
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u_int32_t di_nblk; /* block count */
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u_int32_t di_flags; /* file flags */
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u_int32_t di_osdep1; /* os dependent stuff */
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u_int32_t di_db[NDADDR]; /* direct blocks */
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u_int32_t di_ib[NIADDR]; /* indirect blocks */
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u_int32_t di_version; /* version */
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u_int32_t di_facl; /* file acl */
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u_int32_t di_dacl; /* dir acl */
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u_int32_t di_faddr; /* fragment addr */
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u_int8_t di_frag; /* fragment number */
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u_int8_t di_fsize; /* fragment size */
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char di_pad[10];
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#define di_shortlink di_db
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};
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#define EXT2_MAXNAMLEN 255
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struct ext2dirent {
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u_int32_t d_ino; /* inode */
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u_int16_t d_reclen; /* directory entry length */
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u_int8_t d_namlen; /* name length */
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u_int8_t d_type; /* file type */
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char d_name[EXT2_MAXNAMLEN];
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};
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struct file {
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off_t f_seekp; /* seek pointer */
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struct ext2fs *f_fs; /* pointer to super-block */
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struct ext2blkgrp *f_bg; /* pointer to blkgrp map */
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struct ext2dinode f_di; /* copy of on-disk inode */
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int f_nindir[NIADDR]; /* number of blocks mapped by
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indirect block at level i */
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char *f_blk[NIADDR]; /* buffer for indirect block
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at level i */
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size_t f_blksize[NIADDR]; /* size of buffer */
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daddr_t f_blkno[NIADDR]; /* disk address of block in
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buffer */
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char *f_buf; /* buffer for data block */
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size_t f_buf_size; /* size of data block */
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daddr_t f_buf_blkno; /* block number of data block */
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};
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/* forward decls */
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static int read_inode(ino_t inumber, struct open_file *f);
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static int block_map(struct open_file *f, daddr_t file_block,
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daddr_t *disk_block_p);
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static int buf_read_file(struct open_file *f, char **buf_p,
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size_t *size_p);
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static int search_directory(char *name, struct open_file *f,
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ino_t *inumber_p);
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/*
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* Open a file.
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*/
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static int
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ext2fs_open(const char *upath, struct open_file *f)
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{
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struct file *fp;
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struct ext2fs *fs;
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size_t buf_size;
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ino_t inumber, parent_inumber;
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int i, len, groups, bg_per_blk, blkgrps, mult;
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int nlinks = 0;
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int error = 0;
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char *cp, *ncp, *path = NULL, *buf = NULL;
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char namebuf[MAXPATHLEN+1];
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char c;
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/* allocate file system specific data structure */
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fp = malloc(sizeof(struct file));
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if (fp == NULL)
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return (ENOMEM);
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bzero(fp, sizeof(struct file));
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f->f_fsdata = (void *)fp;
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/* allocate space and read super block */
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fs = (struct ext2fs *)malloc(sizeof(*fs));
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fp->f_fs = fs;
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twiddle();
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error = (f->f_dev->dv_strategy)(f->f_devdata, F_READ,
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EXT2_SBLOCK, EXT2_SBSIZE, (char *)fs, &buf_size);
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if (error)
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goto out;
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if (buf_size != EXT2_SBSIZE || fs->fs_magic != EXT2_MAGIC) {
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error = EINVAL;
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goto out;
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}
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/*
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* compute in-core values for the superblock
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*/
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fs->fs_bshift = EXT2_MINBSHIFT + fs->fs_fd.fd_bsize;
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fs->fs_bsize = 1 << fs->fs_bshift;
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fs->fs_bmask = fs->fs_bsize - 1;
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fs->fs_fshift = EXT2_MINFSHIFT + fs->fs_fd.fd_fsize;
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fs->fs_fsize = 1 << fs->fs_fshift;
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fs->fs_fmask = fs->fs_fsize - 1;
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if (fs->fs_revision == EXT2_REV0) {
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fs->fs_isize = EXT2_R0_ISIZE;
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fs->fs_firstino = EXT2_R0_FIRSTINO;
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} else {
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fs->fs_isize = fs->fs_fd.fd_isize;
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fs->fs_firstino = fs->fs_fd.fd_firstino;
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}
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fs->fs_imask = fs->fs_isize - 1;
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fs->fs_ipb = fs->fs_bsize / fs->fs_isize;
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fs->fs_fsbtodb = (fs->fs_bsize / DEV_BSIZE) - 1;
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/*
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* we have to load in the "group descriptors" here
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*/
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groups = howmany(fs->fs_blocks - fs->fs_firstblk, fs->fs_bpg);
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bg_per_blk = fs->fs_bsize / sizeof(struct ext2blkgrp);
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blkgrps = howmany(groups, bg_per_blk);
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len = blkgrps * fs->fs_bsize;
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fp->f_bg = malloc(len);
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twiddle();
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error = (f->f_dev->dv_strategy)(f->f_devdata, F_READ,
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EXT2_SBLOCK + EXT2_SBSIZE / DEV_BSIZE, len,
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(char *)fp->f_bg, &buf_size);
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if (error)
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goto out;
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/*
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* XXX
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* validation of values? (blocksize, descriptors, etc?)
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*/
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/*
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* Calculate indirect block levels.
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*/
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mult = 1;
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for (i = 0; i < NIADDR; i++) {
|
||||
mult *= nindir(fs);
|
||||
fp->f_nindir[i] = mult;
|
||||
}
|
||||
|
||||
inumber = EXT2_ROOTINO;
|
||||
if ((error = read_inode(inumber, f)) != 0)
|
||||
goto out;
|
||||
|
||||
path = strdup(upath);
|
||||
if (path == NULL) {
|
||||
error = ENOMEM;
|
||||
goto out;
|
||||
}
|
||||
cp = path;
|
||||
while (*cp) {
|
||||
/*
|
||||
* Remove extra separators
|
||||
*/
|
||||
while (*cp == '/')
|
||||
cp++;
|
||||
if (*cp == '\0')
|
||||
break;
|
||||
|
||||
/*
|
||||
* Check that current node is a directory.
|
||||
*/
|
||||
if (! S_ISDIR(fp->f_di.di_mode)) {
|
||||
error = ENOTDIR;
|
||||
goto out;
|
||||
}
|
||||
|
||||
/*
|
||||
* Get next component of path name.
|
||||
*/
|
||||
len = 0;
|
||||
|
||||
ncp = cp;
|
||||
while ((c = *cp) != '\0' && c != '/') {
|
||||
if (++len > EXT2_MAXNAMLEN) {
|
||||
error = ENOENT;
|
||||
goto out;
|
||||
}
|
||||
cp++;
|
||||
}
|
||||
*cp = '\0';
|
||||
|
||||
/*
|
||||
* Look up component in current directory.
|
||||
* Save directory inumber in case we find a
|
||||
* symbolic link.
|
||||
*/
|
||||
parent_inumber = inumber;
|
||||
error = search_directory(ncp, f, &inumber);
|
||||
*cp = c;
|
||||
if (error)
|
||||
goto out;
|
||||
|
||||
/*
|
||||
* Open next component.
|
||||
*/
|
||||
if ((error = read_inode(inumber, f)) != 0)
|
||||
goto out;
|
||||
|
||||
/*
|
||||
* Check for symbolic link.
|
||||
*/
|
||||
if (S_ISLNK(fp->f_di.di_mode)) {
|
||||
int link_len = fp->f_di.di_size;
|
||||
int len;
|
||||
|
||||
len = strlen(cp);
|
||||
if (link_len + len > MAXPATHLEN ||
|
||||
++nlinks > MAXSYMLINKS) {
|
||||
error = ENOENT;
|
||||
goto out;
|
||||
}
|
||||
|
||||
bcopy(cp, &namebuf[link_len], len + 1);
|
||||
if (fp->f_di.di_nblk == 0) {
|
||||
bcopy(fp->f_di.di_shortlink,
|
||||
namebuf, link_len);
|
||||
} else {
|
||||
/*
|
||||
* Read file for symbolic link
|
||||
*/
|
||||
struct ext2fs *fs = fp->f_fs;
|
||||
daddr_t disk_block;
|
||||
size_t buf_size;
|
||||
|
||||
if (! buf)
|
||||
buf = malloc(fs->fs_bsize);
|
||||
error = block_map(f, (daddr_t)0, &disk_block);
|
||||
if (error)
|
||||
goto out;
|
||||
|
||||
twiddle();
|
||||
error = (f->f_dev->dv_strategy)(f->f_devdata,
|
||||
F_READ, fsb_to_db(fs, disk_block),
|
||||
fs->fs_bsize, buf, &buf_size);
|
||||
if (error)
|
||||
goto out;
|
||||
|
||||
bcopy((char *)buf, namebuf, link_len);
|
||||
}
|
||||
|
||||
/*
|
||||
* If relative pathname, restart at parent directory.
|
||||
* If absolute pathname, restart at root.
|
||||
*/
|
||||
cp = namebuf;
|
||||
if (*cp != '/')
|
||||
inumber = parent_inumber;
|
||||
else
|
||||
inumber = (ino_t)EXT2_ROOTINO;
|
||||
|
||||
if ((error = read_inode(inumber, f)) != 0)
|
||||
goto out;
|
||||
}
|
||||
}
|
||||
|
||||
/*
|
||||
* Found terminal component.
|
||||
*/
|
||||
error = 0;
|
||||
out:
|
||||
if (buf)
|
||||
free(buf);
|
||||
if (path)
|
||||
free(path);
|
||||
if (error) {
|
||||
if (fp->f_buf)
|
||||
free(fp->f_buf);
|
||||
free(fp->f_fs);
|
||||
free(fp);
|
||||
}
|
||||
return (error);
|
||||
}
|
||||
|
||||
/*
|
||||
* Read a new inode into a file structure.
|
||||
*/
|
||||
static int
|
||||
read_inode(ino_t inumber, struct open_file *f)
|
||||
{
|
||||
struct file *fp = (struct file *)f->f_fsdata;
|
||||
struct ext2fs *fs = fp->f_fs;
|
||||
struct ext2dinode *dp;
|
||||
char *buf;
|
||||
size_t rsize;
|
||||
int level, error = 0;
|
||||
|
||||
/*
|
||||
* Read inode and save it.
|
||||
*/
|
||||
buf = malloc(fs->fs_bsize);
|
||||
twiddle();
|
||||
error = (f->f_dev->dv_strategy)(f->f_devdata, F_READ,
|
||||
ino_to_db(fs, fp->f_bg, inumber), fs->fs_bsize, buf, &rsize);
|
||||
if (error)
|
||||
goto out;
|
||||
if (rsize != fs->fs_bsize) {
|
||||
error = EIO;
|
||||
goto out;
|
||||
}
|
||||
|
||||
dp = (struct ext2dinode *)buf;
|
||||
fp->f_di = dp[ino_to_bo(fs, inumber)];
|
||||
|
||||
/* clear out old buffers */
|
||||
for (level = 0; level < NIADDR; level++)
|
||||
fp->f_blkno[level] = -1;
|
||||
fp->f_buf_blkno = -1;
|
||||
|
||||
out:
|
||||
free(buf);
|
||||
return (error);
|
||||
}
|
||||
|
||||
/*
|
||||
* Given an offset in a file, find the disk block number that
|
||||
* contains that block.
|
||||
*/
|
||||
static int
|
||||
block_map(struct open_file *f, daddr_t file_block, daddr_t *disk_block_p)
|
||||
{
|
||||
struct file *fp = (struct file *)f->f_fsdata;
|
||||
struct ext2fs *fs = fp->f_fs;
|
||||
daddr_t ind_block_num;
|
||||
daddr_t *ind_p;
|
||||
int idx, level;
|
||||
int error;
|
||||
|
||||
/*
|
||||
* Index structure of an inode:
|
||||
*
|
||||
* di_db[0..NDADDR-1] hold block numbers for blocks
|
||||
* 0..NDADDR-1
|
||||
*
|
||||
* di_ib[0] index block 0 is the single indirect block
|
||||
* holds block numbers for blocks
|
||||
* NDADDR .. NDADDR + NINDIR(fs)-1
|
||||
*
|
||||
* di_ib[1] index block 1 is the double indirect block
|
||||
* holds block numbers for INDEX blocks for blocks
|
||||
* NDADDR + NINDIR(fs) ..
|
||||
* NDADDR + NINDIR(fs) + NINDIR(fs)**2 - 1
|
||||
*
|
||||
* di_ib[2] index block 2 is the triple indirect block
|
||||
* holds block numbers for double-indirect
|
||||
* blocks for blocks
|
||||
* NDADDR + NINDIR(fs) + NINDIR(fs)**2 ..
|
||||
* NDADDR + NINDIR(fs) + NINDIR(fs)**2
|
||||
* + NINDIR(fs)**3 - 1
|
||||
*/
|
||||
|
||||
if (file_block < NDADDR) {
|
||||
/* Direct block. */
|
||||
*disk_block_p = fp->f_di.di_db[file_block];
|
||||
return (0);
|
||||
}
|
||||
|
||||
file_block -= NDADDR;
|
||||
|
||||
/*
|
||||
* nindir[0] = NINDIR
|
||||
* nindir[1] = NINDIR**2
|
||||
* nindir[2] = NINDIR**3
|
||||
* etc
|
||||
*/
|
||||
for (level = 0; level < NIADDR; level++) {
|
||||
if (file_block < fp->f_nindir[level])
|
||||
break;
|
||||
file_block -= fp->f_nindir[level];
|
||||
}
|
||||
if (level == NIADDR) {
|
||||
/* Block number too high */
|
||||
return (EFBIG);
|
||||
}
|
||||
|
||||
ind_block_num = fp->f_di.di_ib[level];
|
||||
|
||||
for (; level >= 0; level--) {
|
||||
if (ind_block_num == 0) {
|
||||
*disk_block_p = 0; /* missing */
|
||||
return (0);
|
||||
}
|
||||
|
||||
if (fp->f_blkno[level] != ind_block_num) {
|
||||
if (fp->f_blk[level] == (char *)0)
|
||||
fp->f_blk[level] =
|
||||
malloc(fs->fs_bsize);
|
||||
twiddle();
|
||||
error = (f->f_dev->dv_strategy)(f->f_devdata, F_READ,
|
||||
fsb_to_db(fp->f_fs, ind_block_num), fs->fs_bsize,
|
||||
fp->f_blk[level], &fp->f_blksize[level]);
|
||||
if (error)
|
||||
return (error);
|
||||
if (fp->f_blksize[level] != fs->fs_bsize)
|
||||
return (EIO);
|
||||
fp->f_blkno[level] = ind_block_num;
|
||||
}
|
||||
|
||||
ind_p = (daddr_t *)fp->f_blk[level];
|
||||
|
||||
if (level > 0) {
|
||||
idx = file_block / fp->f_nindir[level - 1];
|
||||
file_block %= fp->f_nindir[level - 1];
|
||||
} else {
|
||||
idx = file_block;
|
||||
}
|
||||
ind_block_num = ind_p[idx];
|
||||
}
|
||||
|
||||
*disk_block_p = ind_block_num;
|
||||
|
||||
return (0);
|
||||
}
|
||||
|
||||
/*
|
||||
* Read a portion of a file into an internal buffer. Return
|
||||
* the location in the buffer and the amount in the buffer.
|
||||
*/
|
||||
static int
|
||||
buf_read_file(struct open_file *f, char **buf_p, size_t *size_p)
|
||||
{
|
||||
struct file *fp = (struct file *)f->f_fsdata;
|
||||
struct ext2fs *fs = fp->f_fs;
|
||||
long off;
|
||||
daddr_t file_block;
|
||||
daddr_t disk_block;
|
||||
size_t block_size;
|
||||
int error = 0;
|
||||
|
||||
off = blkoff(fs, fp->f_seekp);
|
||||
file_block = lblkno(fs, fp->f_seekp);
|
||||
block_size = dblksize(fs, &fp->f_di, file_block);
|
||||
|
||||
if (file_block != fp->f_buf_blkno) {
|
||||
error = block_map(f, file_block, &disk_block);
|
||||
if (error)
|
||||
goto done;
|
||||
|
||||
if (fp->f_buf == (char *)0)
|
||||
fp->f_buf = malloc(fs->fs_bsize);
|
||||
|
||||
if (disk_block == 0) {
|
||||
bzero(fp->f_buf, block_size);
|
||||
fp->f_buf_size = block_size;
|
||||
} else {
|
||||
twiddle();
|
||||
error = (f->f_dev->dv_strategy)(f->f_devdata, F_READ,
|
||||
fsb_to_db(fs, disk_block), block_size,
|
||||
fp->f_buf, &fp->f_buf_size);
|
||||
if (error)
|
||||
goto done;
|
||||
}
|
||||
fp->f_buf_blkno = file_block;
|
||||
}
|
||||
|
||||
/*
|
||||
* Return address of byte in buffer corresponding to
|
||||
* offset, and size of remainder of buffer after that
|
||||
* byte.
|
||||
*/
|
||||
*buf_p = fp->f_buf + off;
|
||||
*size_p = block_size - off;
|
||||
|
||||
/*
|
||||
* But truncate buffer at end of file.
|
||||
*/
|
||||
if (*size_p > fp->f_di.di_size - fp->f_seekp)
|
||||
*size_p = fp->f_di.di_size - fp->f_seekp;
|
||||
done:
|
||||
return (error);
|
||||
}
|
||||
|
||||
/*
|
||||
* Search a directory for a name and return its
|
||||
* i_number.
|
||||
*/
|
||||
static int
|
||||
search_directory(char *name, struct open_file *f, ino_t *inumber_p)
|
||||
{
|
||||
struct file *fp = (struct file *)f->f_fsdata;
|
||||
struct ext2dirent *dp, *edp;
|
||||
char *buf;
|
||||
size_t buf_size;
|
||||
int namlen, length;
|
||||
int error;
|
||||
|
||||
length = strlen(name);
|
||||
fp->f_seekp = 0;
|
||||
while (fp->f_seekp < fp->f_di.di_size) {
|
||||
error = buf_read_file(f, &buf, &buf_size);
|
||||
if (error)
|
||||
return (error);
|
||||
dp = (struct ext2dirent *)buf;
|
||||
edp = (struct ext2dirent *)(buf + buf_size);
|
||||
while (dp < edp) {
|
||||
if (dp->d_ino == (ino_t)0)
|
||||
goto next;
|
||||
namlen = dp->d_namlen;
|
||||
if (namlen == length &&
|
||||
strncmp(name, dp->d_name, length) == 0) {
|
||||
/* found entry */
|
||||
*inumber_p = dp->d_ino;
|
||||
return (0);
|
||||
}
|
||||
next:
|
||||
dp = (struct ext2dirent *)((char *)dp + dp->d_reclen);
|
||||
}
|
||||
fp->f_seekp += buf_size;
|
||||
}
|
||||
return (ENOENT);
|
||||
}
|
||||
|
||||
static int
|
||||
ext2fs_close(struct open_file *f)
|
||||
{
|
||||
struct file *fp = (struct file *)f->f_fsdata;
|
||||
int level;
|
||||
|
||||
f->f_fsdata = (void *)0;
|
||||
if (fp == (struct file *)0)
|
||||
return (0);
|
||||
|
||||
for (level = 0; level < NIADDR; level++) {
|
||||
if (fp->f_blk[level])
|
||||
free(fp->f_blk[level]);
|
||||
}
|
||||
if (fp->f_buf)
|
||||
free(fp->f_buf);
|
||||
if (fp->f_bg)
|
||||
free(fp->f_bg);
|
||||
free(fp->f_fs);
|
||||
free(fp);
|
||||
return (0);
|
||||
}
|
||||
|
||||
static int
|
||||
ext2fs_read(struct open_file *f, void *addr, size_t size, size_t *resid)
|
||||
{
|
||||
struct file *fp = (struct file *)f->f_fsdata;
|
||||
size_t csize, buf_size;
|
||||
char *buf;
|
||||
int error = 0;
|
||||
|
||||
while (size != 0) {
|
||||
if (fp->f_seekp >= fp->f_di.di_size)
|
||||
break;
|
||||
|
||||
error = buf_read_file(f, &buf, &buf_size);
|
||||
if (error)
|
||||
break;
|
||||
|
||||
csize = size;
|
||||
if (csize > buf_size)
|
||||
csize = buf_size;
|
||||
|
||||
bcopy(buf, addr, csize);
|
||||
|
||||
fp->f_seekp += csize;
|
||||
addr += csize;
|
||||
size -= csize;
|
||||
}
|
||||
if (resid)
|
||||
*resid = size;
|
||||
return (error);
|
||||
}
|
||||
|
||||
static off_t
|
||||
ext2fs_seek(struct open_file *f, off_t offset, int where)
|
||||
{
|
||||
struct file *fp = (struct file *)f->f_fsdata;
|
||||
|
||||
switch (where) {
|
||||
case SEEK_SET:
|
||||
fp->f_seekp = offset;
|
||||
break;
|
||||
case SEEK_CUR:
|
||||
fp->f_seekp += offset;
|
||||
break;
|
||||
case SEEK_END:
|
||||
fp->f_seekp = fp->f_di.di_size - offset;
|
||||
break;
|
||||
default:
|
||||
return (-1);
|
||||
}
|
||||
return (fp->f_seekp);
|
||||
}
|
||||
|
||||
static int
|
||||
ext2fs_stat(struct open_file *f, struct stat *sb)
|
||||
{
|
||||
struct file *fp = (struct file *)f->f_fsdata;
|
||||
|
||||
/* only important stuff */
|
||||
sb->st_mode = fp->f_di.di_mode;
|
||||
sb->st_uid = fp->f_di.di_uid;
|
||||
sb->st_gid = fp->f_di.di_gid;
|
||||
sb->st_size = fp->f_di.di_size;
|
||||
return (0);
|
||||
}
|
||||
|
||||
static int
|
||||
ext2fs_readdir(struct open_file *f, struct dirent *d)
|
||||
{
|
||||
struct file *fp = (struct file *)f->f_fsdata;
|
||||
struct ext2dirent *ed;
|
||||
char *buf;
|
||||
size_t buf_size;
|
||||
int error;
|
||||
|
||||
/*
|
||||
* assume that a directory entry will not be split across blocks
|
||||
*/
|
||||
again:
|
||||
if (fp->f_seekp >= fp->f_di.di_size)
|
||||
return (ENOENT);
|
||||
error = buf_read_file(f, &buf, &buf_size);
|
||||
if (error)
|
||||
return (error);
|
||||
ed = (struct ext2dirent *)buf;
|
||||
fp->f_seekp += ed->d_reclen;
|
||||
if (ed->d_ino == (ino_t)0)
|
||||
goto again;
|
||||
d->d_type = EXTFTODT(ed->d_type);
|
||||
strncpy(d->d_name, ed->d_name, ed->d_namlen);
|
||||
d->d_name[ed->d_namlen] = '\0';
|
||||
return (0);
|
||||
}
|
||||
Loading…
Reference in New Issue
Block a user