NetBSD/sys/lib/libsa/lfs.c

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2000-03-30 16:19:46 +04:00
/* $NetBSD: lfs.c,v 1.6 2000/03/30 12:19:48 augustss Exp $ */
/*-
* Copyright (c) 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* The Mach Operating System project at Carnegie-Mellon University.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
*
* Copyright (c) 1990, 1991 Carnegie Mellon University
* All Rights Reserved.
*
* Author: David Golub
*
* Permission to use, copy, modify and distribute this software and its
* documentation is hereby granted, provided that both the copyright
* notice and this permission notice appear in all copies of the
* software, derivative works or modified versions, and any portions
* thereof, and that both notices appear in supporting documentation.
*
* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
* ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
*
* Carnegie Mellon requests users of this software to return to
*
* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
* School of Computer Science
* Carnegie Mellon University
* Pittsburgh PA 15213-3890
*
* any improvements or extensions that they make and grant Carnegie the
* rights to redistribute these changes.
*/
/*
* XXX NOTE: ufs.c (FFS) and lfs.c (LFS) should eventually use much common
* XXX code. until then, the two files should be easily diffable.
*/
/*
* Stand-alone file reading package.
*/
#include <sys/param.h>
#include <sys/time.h>
#include <sys/mount.h> /* XXX for MNAMELEN */
#include <ufs/ufs/dinode.h>
#include <ufs/ufs/dir.h>
#include <ufs/lfs/lfs.h>
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#ifdef _STANDALONE
#include <lib/libkern/libkern.h>
#else
#include <string.h>
inline u_int
max(a, b)
u_int a, b;
{
return (a > b ? a : b);
}
#endif
#include "stand.h"
#include "lfs.h"
#if defined(LIBSA_FS_SINGLECOMPONENT) && !defined(LIBSA_NO_FS_SYMLINK)
#define LIBSA_NO_FS_SYMLINK
#endif
/*
* In-core LFS superblock. This exists only to placate the macros in lfs.h,
* and to diff easily against the UFS code.
*/
struct fs {
struct dlfs lfs_dlfs;
};
#define fs_magic lfs_magic
#define fs_bsize lfs_bsize
#define fs_maxsymlinklen lfs_maxsymlinklen
#define FS_MAGIC LFS_MAGIC
#define SBSIZE LFS_SBPAD
#define SBLOCK (LFS_LABELPAD / DEV_BSIZE)
/*
* In-core open file.
*/
struct file {
off_t f_seekp; /* seek pointer */
struct fs *f_fs; /* pointer to super-block */
struct dinode f_di; /* copy of on-disk inode */
unsigned int f_nindir[NIADDR];
/* number of blocks mapped by
indirect block at level i */
char *f_blk[NIADDR]; /* buffer for indirect block at
level i */
size_t f_blksize[NIADDR];
/* size of buffer */
daddr_t f_blkno[NIADDR];/* disk address of block in buffer */
char *f_buf; /* buffer for data block */
size_t f_buf_size; /* size of data block */
daddr_t f_buf_blkno; /* block number of data block */
};
static int find_inode_sector(ino_t inumber, struct open_file *f,
ufs_daddr_t *ibp);
static int read_inode __P((ino_t, struct open_file *));
static int block_map __P((struct open_file *, daddr_t, daddr_t *));
static int buf_read_file __P((struct open_file *, char **, size_t *));
static int search_directory __P((char *, struct open_file *, ino_t *));
/*
* Find an inode's block. Look it up in the ifile. Whee!
*/
static int
find_inode_sector(ino_t inumber, struct open_file *f, ufs_daddr_t *isp)
{
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struct file *fp = (struct file *)f->f_fsdata;
struct fs *fs = fp->f_fs;
ufs_daddr_t ifileent_blkno;
char *ent_in_buf;
size_t buf_after_ent;
int rc;
rc = read_inode(fs->lfs_ifile, f);
if (rc)
return (rc);
ifileent_blkno =
(inumber / fs->lfs_ifpb) + fs->lfs_cleansz + fs->lfs_segtabsz;
fp->f_seekp = (off_t)ifileent_blkno * fs->fs_bsize +
(inumber % fs->lfs_ifpb) * sizeof (IFILE);
rc = buf_read_file(f, &ent_in_buf, &buf_after_ent);
if (rc)
return (rc);
/* make sure something's not badly wrong, but don't panic. */
if (buf_after_ent < sizeof (IFILE))
return (EINVAL);
#if 0 /* LFS daddr_t's are in sectors, fsbtodb() shouldn't be used on them */
*isp = fsbtodb(fs, ((IFILE *)ent_in_buf)->if_daddr);
#else
*isp = ((IFILE *)ent_in_buf)->if_daddr;
#endif
if (*isp == LFS_UNUSED_DADDR) /* again, something badly wrong */
return (EINVAL);
return (0);
}
/*
* Read a new inode into a file structure.
*/
static int
read_inode(inumber, f)
ino_t inumber;
struct open_file *f;
{
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struct file *fp = (struct file *)f->f_fsdata;
struct fs *fs = fp->f_fs;
struct dinode *dip;
ufs_daddr_t inode_sector;
size_t rsize;
char *buf;
int rc, cnt;
if (inumber == fs->lfs_ifile)
inode_sector = fs->lfs_idaddr;
else if ((rc = find_inode_sector(inumber, f, &inode_sector)) != 0)
return (rc);
/*
* Read inode and save it.
*/
buf = alloc(fs->fs_bsize);
#if !defined(LIBSA_NO_TWIDDLE)
twiddle();
#endif
rc = DEV_STRATEGY(f->f_dev)(f->f_devdata, F_READ,
inode_sector, fs->fs_bsize,
buf, &rsize);
if (rc)
goto out;
if (rsize != fs->fs_bsize) {
rc = EIO;
goto out;
}
rc = EINVAL;
cnt = INOPB(fs);
for (dip = (struct dinode *)buf + (cnt - 1); cnt--; --dip) {
if (dip->di_inumber == inumber) {
rc = 0;
break;
}
}
/* kernel code panics, but boot blocks which panic are Bad. */
if (rc)
goto out;
fp->f_di = *dip;
/*
* Clear out the old buffers
*/
{
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int level;
for (level = 0; level < NIADDR; level++)
fp->f_blkno[level] = -1;
fp->f_buf_blkno = -1;
}
out:
free(buf, fs->fs_bsize);
return (rc);
}
/*
* Given an offset in a file, find the disk block number that
* contains that block.
*/
static int
block_map(f, file_block, disk_block_p)
struct open_file *f;
daddr_t file_block;
daddr_t *disk_block_p; /* out */
{
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struct file *fp = (struct file *)f->f_fsdata;
struct fs *fs = fp->f_fs;
int level;
int idx;
daddr_t ind_block_num;
daddr_t *ind_p;
int rc;
/*
* 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] =
alloc(fs->fs_bsize);
#if !defined(LIBSA_NO_TWIDDLE)
twiddle();
#endif
rc = DEV_STRATEGY(f->f_dev)(f->f_devdata, F_READ,
#if 0 /* LFS daddr_t's are in sectors, fsbtodb() shouldn't be used on them */
fsbtodb(fp->f_fs, ind_block_num),
#else
ind_block_num,
#endif
fs->fs_bsize,
fp->f_blk[level],
&fp->f_blksize[level]);
if (rc)
return (rc);
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(f, buf_p, size_p)
struct open_file *f;
char **buf_p; /* out */
size_t *size_p; /* out */
{
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struct file *fp = (struct file *)f->f_fsdata;
struct fs *fs = fp->f_fs;
long off;
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daddr_t file_block;
daddr_t disk_block;
size_t block_size;
int rc;
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) {
rc = block_map(f, file_block, &disk_block);
if (rc)
return (rc);
if (fp->f_buf == (char *)0)
fp->f_buf = alloc(fs->fs_bsize);
if (disk_block == 0) {
bzero(fp->f_buf, block_size);
fp->f_buf_size = block_size;
} else {
#if !defined(LIBSA_NO_TWIDDLE)
twiddle();
#endif
rc = DEV_STRATEGY(f->f_dev)(f->f_devdata, F_READ,
#if 0 /* LFS daddr_t's are in sectors, fsbtodb() shouldn't be used on them */
fsbtodb(fs, disk_block),
#else
disk_block,
#endif
block_size, fp->f_buf, &fp->f_buf_size);
if (rc)
return (rc);
}
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;
return (0);
}
/*
* Search a directory for a name and return its
* i_number.
*/
static int
search_directory(name, f, inumber_p)
char *name;
struct open_file *f;
ino_t *inumber_p; /* out */
{
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struct file *fp = (struct file *)f->f_fsdata;
struct direct *dp;
struct direct *edp;
char *buf;
size_t buf_size;
int namlen, length;
int rc;
length = strlen(name);
fp->f_seekp = 0;
while (fp->f_seekp < fp->f_di.di_size) {
rc = buf_read_file(f, &buf, &buf_size);
if (rc)
return (rc);
dp = (struct direct *)buf;
edp = (struct direct *)(buf + buf_size);
while (dp < edp) {
if (dp->d_ino == (ino_t)0)
goto next;
#if BYTE_ORDER == LITTLE_ENDIAN
if (fp->f_fs->fs_maxsymlinklen <= 0)
namlen = dp->d_type;
else
#endif
namlen = dp->d_namlen;
if (namlen == length &&
!strcmp(name, dp->d_name)) {
/* found entry */
*inumber_p = dp->d_ino;
return (0);
}
next:
dp = (struct direct *)((char *)dp + dp->d_reclen);
}
fp->f_seekp += buf_size;
}
return (ENOENT);
}
/*
* Open a file.
*/
int
lfs_open(path, f)
char *path;
struct open_file *f;
{
#ifndef LIBSA_FS_SINGLECOMPONENT
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char *cp, *ncp;
int c;
#endif
ino_t inumber;
struct file *fp;
struct fs *fs;
int rc;
size_t buf_size;
#ifndef LIBSA_NO_FS_SYMLINK
ino_t parent_inumber;
int nlinks = 0;
char namebuf[MAXPATHLEN+1];
char *buf = NULL;
#endif
/* allocate file system specific data structure */
fp = alloc(sizeof(struct file));
bzero(fp, sizeof(struct file));
f->f_fsdata = (void *)fp;
/* allocate space and read super block */
fs = alloc(SBSIZE);
fp->f_fs = fs;
#if !defined(LIBSA_NO_TWIDDLE)
twiddle();
#endif
rc = DEV_STRATEGY(f->f_dev)(f->f_devdata, F_READ,
SBLOCK, SBSIZE, (char *)fs, &buf_size);
if (rc)
goto out;
if (buf_size != SBSIZE || fs->fs_magic != FS_MAGIC ||
fs->fs_bsize > MAXBSIZE || fs->fs_bsize < sizeof(struct fs)) {
rc = EINVAL;
goto out;
}
/*
* Calculate indirect block levels.
*/
{
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int mult;
int level;
mult = 1;
for (level = 0; level < NIADDR; level++) {
mult *= NINDIR(fs);
fp->f_nindir[level] = mult;
}
}
inumber = ROOTINO;
if ((rc = read_inode(inumber, f)) != 0)
goto out;
#ifndef LIBSA_FS_SINGLECOMPONENT
cp = path;
while (*cp) {
/*
* Remove extra separators
*/
while (*cp == '/')
cp++;
if (*cp == '\0')
break;
/*
* Check that current node is a directory.
*/
if ((fp->f_di.di_mode & IFMT) != IFDIR) {
rc = ENOTDIR;
goto out;
}
/*
* Get next component of path name.
*/
{
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int len = 0;
ncp = cp;
while ((c = *cp) != '\0' && c != '/') {
if (++len > MAXNAMLEN) {
rc = ENOENT;
goto out;
}
cp++;
}
*cp = '\0';
}
/*
* Look up component in current directory.
* Save directory inumber in case we find a
* symbolic link.
*/
#ifndef LIBSA_NO_FS_SYMLINK
parent_inumber = inumber;
#endif
rc = search_directory(ncp, f, &inumber);
*cp = c;
if (rc)
goto out;
/*
* Open next component.
*/
if ((rc = read_inode(inumber, f)) != 0)
goto out;
#ifndef LIBSA_NO_FS_SYMLINK
/*
* Check for symbolic link.
*/
if ((fp->f_di.di_mode & IFMT) == IFLNK) {
int link_len = fp->f_di.di_size;
int len;
len = strlen(cp);
if (link_len + len > MAXPATHLEN ||
++nlinks > MAXSYMLINKS) {
rc = ENOENT;
goto out;
}
bcopy(cp, &namebuf[link_len], len + 1);
if (link_len < fs->fs_maxsymlinklen) {
bcopy(fp->f_di.di_shortlink, namebuf,
(unsigned) link_len);
} else {
/*
* Read file for symbolic link
*/
size_t buf_size;
daddr_t disk_block;
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struct fs *fs = fp->f_fs;
if (!buf)
buf = alloc(fs->fs_bsize);
rc = block_map(f, (daddr_t)0, &disk_block);
if (rc)
goto out;
#if !defined(LIBSA_NO_TWIDDLE)
twiddle();
#endif
rc = DEV_STRATEGY(f->f_dev)(f->f_devdata,
#if 0 /* LFS daddr_t's are in sectors, fsbtodb() shouldn't be used on them */
F_READ, fsbtodb(fs, disk_block),
#else
F_READ, disk_block,
#endif
fs->fs_bsize, buf, &buf_size);
if (rc)
goto out;
bcopy((char *)buf, namebuf, (unsigned)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)ROOTINO;
if ((rc = read_inode(inumber, f)) != 0)
goto out;
}
#endif /* !LIBSA_NO_FS_SYMLINK */
}
/*
* Found terminal component.
*/
rc = 0;
#else /* !LIBSA_FS_SINGLECOMPONENT */
/* look up component in the current (root) directory */
rc = search_directory(path, f, &inumber);
if (rc)
goto out;
/* open it */
rc = read_inode(inumber, f);
#endif /* !LIBSA_FS_SINGLECOMPONENT */
fp->f_seekp = 0; /* reset seek pointer */
out:
#ifndef LIBSA_NO_FS_SYMLINK
if (buf)
free(buf, fs->fs_bsize);
#endif
if (rc) {
if (fp->f_buf)
free(fp->f_buf, fp->f_fs->fs_bsize);
free(fp->f_fs, SBSIZE);
free(fp, sizeof(struct file));
}
return (rc);
}
#ifndef LIBSA_NO_FS_CLOSE
int
lfs_close(f)
struct open_file *f;
{
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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], fp->f_fs->fs_bsize);
}
if (fp->f_buf)
free(fp->f_buf, fp->f_fs->fs_bsize);
free(fp->f_fs, SBSIZE);
free(fp, sizeof(struct file));
return (0);
}
#endif /* !LIBSA_NO_FS_CLOSE */
/*
* Copy a portion of a file into kernel memory.
* Cross block boundaries when necessary.
*/
int
lfs_read(f, start, size, resid)
struct open_file *f;
void *start;
size_t size;
size_t *resid; /* out */
{
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struct file *fp = (struct file *)f->f_fsdata;
size_t csize;
char *buf;
size_t buf_size;
int rc = 0;
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char *addr = start;
while (size != 0) {
if (fp->f_seekp >= fp->f_di.di_size)
break;
rc = buf_read_file(f, &buf, &buf_size);
if (rc)
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 (rc);
}
/*
* Not implemented.
*/
#ifndef LIBSA_NO_FS_WRITE
int
lfs_write(f, start, size, resid)
struct open_file *f;
void *start;
size_t size;
size_t *resid; /* out */
{
return (EROFS);
}
#endif /* !LIBSA_NO_FS_WRITE */
#ifndef LIBSA_NO_FS_SEEK
off_t
lfs_seek(f, offset, where)
struct open_file *f;
off_t offset;
int where;
{
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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);
}
#endif /* !LIBSA_NO_FS_SEEK */
int
lfs_stat(f, sb)
struct open_file *f;
struct stat *sb;
{
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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);
}