freebsd-src/lib/libstand/ufs.c
Jonathan Lemon efb8ff8532 Add a readdir function to the loader fsops vector, and implement the
functionality for some of the filesystesms.
2000-04-29 20:47:10 +00:00

754 lines
17 KiB
C

/* $FreeBSD$ */
/* $NetBSD: ufs.c,v 1.20 1998/03/01 07:15:39 ross 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.
*/
/*
* Stand-alone file reading package.
*/
#include <sys/param.h>
#include <sys/time.h>
#include <ufs/ufs/dinode.h>
#include <ufs/ufs/dir.h>
#include <ufs/ffs/fs.h>
#include "stand.h"
#include "string.h"
#ifdef __alpha__
#define COMPAT_UFS /* DUX has old format file systems */
#endif
static int ufs_open(const char *path, struct open_file *f);
static int ufs_close(struct open_file *f);
static int ufs_read(struct open_file *f, void *buf, size_t size, size_t *resid);
static off_t ufs_seek(struct open_file *f, off_t offset, int where);
static int ufs_stat(struct open_file *f, struct stat *sb);
static int ufs_readdir(struct open_file *f, struct dirent *d);
struct fs_ops ufs_fsops = {
"ufs",
ufs_open,
ufs_close,
ufs_read,
null_write,
ufs_seek,
ufs_stat,
ufs_readdir
};
/*
* 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 */
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 read_inode(ino_t, struct open_file *);
static int block_map(struct open_file *, daddr_t, daddr_t *);
static int buf_read_file(struct open_file *, char **, size_t *);
static int search_directory(char *, struct open_file *, ino_t *);
#ifdef COMPAT_UFS
static void ffs_oldfscompat(struct fs *);
#endif
/*
* Read a new inode into a file structure.
*/
static int
read_inode(inumber, f)
ino_t inumber;
struct open_file *f;
{
register struct file *fp = (struct file *)f->f_fsdata;
register struct fs *fs = fp->f_fs;
char *buf;
size_t rsize;
int rc;
if (fs == NULL)
panic("fs == NULL");
/*
* Read inode and save it.
*/
buf = malloc(fs->fs_bsize);
twiddle();
rc = (f->f_dev->dv_strategy)(f->f_devdata, F_READ,
fsbtodb(fs, ino_to_fsba(fs, inumber)), fs->fs_bsize,
buf, &rsize);
if (rc)
goto out;
if (rsize != fs->fs_bsize) {
rc = EIO;
goto out;
}
{
register struct dinode *dp;
dp = (struct dinode *)buf;
fp->f_di = dp[ino_to_fsbo(fs, inumber)];
}
/*
* Clear out the old buffers
*/
{
register int level;
for (level = 0; level < NIADDR; level++)
fp->f_blkno[level] = -1;
fp->f_buf_blkno = -1;
}
out:
free(buf);
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 */
{
register struct file *fp = (struct file *)f->f_fsdata;
register 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] =
malloc(fs->fs_bsize);
twiddle();
rc = (f->f_dev->dv_strategy)(f->f_devdata, F_READ,
fsbtodb(fp->f_fs, ind_block_num),
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 */
{
register struct file *fp = (struct file *)f->f_fsdata;
register struct fs *fs = fp->f_fs;
long off;
register 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 = malloc(fs->fs_bsize);
if (disk_block == 0) {
bzero(fp->f_buf, block_size);
fp->f_buf_size = block_size;
} else {
twiddle();
rc = (f->f_dev->dv_strategy)(f->f_devdata, F_READ,
fsbtodb(fs, disk_block),
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 */
{
register struct file *fp = (struct file *)f->f_fsdata;
register 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.
*/
static int
ufs_open(upath, f)
const char *upath;
struct open_file *f;
{
register char *cp, *ncp;
register int c;
ino_t inumber, parent_inumber;
struct file *fp;
struct fs *fs;
int rc;
size_t buf_size;
int nlinks = 0;
char namebuf[MAXPATHLEN+1];
char *buf = NULL;
char *path = NULL;
/* allocate file system specific data structure */
fp = malloc(sizeof(struct file));
bzero(fp, sizeof(struct file));
f->f_fsdata = (void *)fp;
/* allocate space and read super block */
fs = malloc(SBSIZE);
fp->f_fs = fs;
twiddle();
rc = (f->f_dev->dv_strategy)(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;
}
#ifdef COMPAT_UFS
ffs_oldfscompat(fs);
#endif
/*
* Calculate indirect block levels.
*/
{
register int mult;
register 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;
cp = path = strdup(upath);
if (path == NULL) {
rc = ENOMEM;
goto out;
}
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.
*/
{
register 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.
*/
parent_inumber = inumber;
rc = search_directory(ncp, f, &inumber);
*cp = c;
if (rc)
goto out;
/*
* Open next component.
*/
if ((rc = read_inode(inumber, f)) != 0)
goto out;
/*
* 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;
register struct fs *fs = fp->f_fs;
if (!buf)
buf = malloc(fs->fs_bsize);
rc = block_map(f, (daddr_t)0, &disk_block);
if (rc)
goto out;
twiddle();
rc = (f->f_dev->dv_strategy)(f->f_devdata,
F_READ, fsbtodb(fs, disk_block),
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;
}
}
/*
* Found terminal component.
*/
rc = 0;
out:
if (buf)
free(buf);
if (path)
free(path);
if (rc) {
if (fp->f_buf)
free(fp->f_buf);
free(fp->f_fs);
free(fp);
}
return (rc);
}
static int
ufs_close(f)
struct open_file *f;
{
register 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);
free(fp->f_fs);
free(fp);
return (0);
}
/*
* Copy a portion of a file into kernel memory.
* Cross block boundaries when necessary.
*/
static int
ufs_read(f, start, size, resid)
struct open_file *f;
void *start;
size_t size;
size_t *resid; /* out */
{
register struct file *fp = (struct file *)f->f_fsdata;
register size_t csize;
char *buf;
size_t buf_size;
int rc = 0;
register 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);
}
static off_t
ufs_seek(f, offset, where)
struct open_file *f;
off_t offset;
int where;
{
register 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
ufs_stat(f, sb)
struct open_file *f;
struct stat *sb;
{
register 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
ufs_readdir(struct open_file *f, struct dirent *d)
{
struct file *fp = (struct file *)f->f_fsdata;
struct direct *dp;
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);
dp = (struct direct *)buf;
fp->f_seekp += dp->d_reclen;
if (dp->d_ino == (ino_t)0)
goto again;
d->d_type = dp->d_type;
strcpy(d->d_name, dp->d_name);
return (0);
}
#ifdef COMPAT_UFS
/*
* Sanity checks for old file systems.
*
* XXX - goes away some day.
*/
static void
ffs_oldfscompat(fs)
struct fs *fs;
{
int i;
fs->fs_npsect = max(fs->fs_npsect, fs->fs_nsect); /* XXX */
fs->fs_interleave = max(fs->fs_interleave, 1); /* XXX */
if (fs->fs_postblformat == FS_42POSTBLFMT) /* XXX */
fs->fs_nrpos = 8; /* XXX */
if (fs->fs_inodefmt < FS_44INODEFMT) { /* XXX */
quad_t sizepb = fs->fs_bsize; /* XXX */
/* XXX */
fs->fs_maxfilesize = fs->fs_bsize * NDADDR - 1; /* XXX */
for (i = 0; i < NIADDR; i++) { /* XXX */
sizepb *= NINDIR(fs); /* XXX */
fs->fs_maxfilesize += sizepb; /* XXX */
} /* XXX */
fs->fs_qbmask = ~fs->fs_bmask; /* XXX */
fs->fs_qfmask = ~fs->fs_fmask; /* XXX */
} /* XXX */
}
#endif