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4.4BSD snapshot (revision 8.1); add 1993 to copyright
[unix-history] / usr / src / sys / stand / ufs.c
/*-
* 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.
*
* %sccs.include.redist.c%
*
* @(#)ufs.c 8.1 (Berkeley) %G%
*
*
* 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/ffs/fs.h>
#include <ufs/ufs/dinode.h>
#include <ufs/ufs/dir.h>
#include <stand/stand.h>
/*
* 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 */
u_long f_blksize[NIADDR];
/* size of buffer */
daddr_t f_blkno[NIADDR];/* disk address of block in buffer */
char *f_buf; /* buffer for data block */
u_int f_buf_size; /* size of data block */
daddr_t f_buf_blkno; /* block number of data block */
};
/*
* 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;
u_int rsize;
int rc;
/*
* Read inode and save it.
*/
buf = alloc(fs->fs_bsize);
rc = (f->f_dev->dv_strategy)(f->f_devdata, F_READ,
fsbtodb(fs, itod(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[itoo(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, fs->fs_bsize);
return (0);
}
/*
* 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] =
alloc(fs->fs_bsize);
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 */
u_int *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;
long 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 {
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;
u_int 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
ufs_open(path, f)
char *path;
struct open_file *f;
{
register char *cp, *ncp;
register int c;
ino_t inumber, parent_inumber;
int nlinks = 0;
struct file *fp;
struct fs *fs;
int rc;
u_int buf_size;
#if 0
char namebuf[MAXPATHLEN+1];
#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;
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;
}
/*
* 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;
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;
#if 0
/*
* Check for symbolic link.
*/
if ((fp->i_mode & IFMT) == IFLNK) {
int link_len = fp->f_di.di_size;
int len;
len = strlen(cp) + 1;
if (fp->f_di.di_size >= MAXPATHLEN - 1 ||
++nlinks > MAXSYMLINKS) {
rc = ENOENT;
goto out;
}
strcpy(&namebuf[link_len], cp);
if ((fp->i_flags & IC_FASTLINK) != 0) {
bcopy(fp->i_symlink, namebuf, (unsigned) link_len);
} else {
/*
* Read file for symbolic link
*/
char *buf;
u_int buf_size;
daddr_t disk_block;
register struct fs *fs = fp->f_fs;
(void) block_map(f, (daddr_t)0, &disk_block);
rc = device_read(&fp->f_dev,
fsbtodb(fs, disk_block),
blksize(fs, fp, 0),
&buf, &buf_size);
if (rc)
goto out;
bcopy((char *)buf, namebuf, (unsigned)link_len);
free(buf, buf_size);
}
/*
* 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, fp)) != 0)
goto out;
}
#endif
}
/*
* Found terminal component.
*/
rc = 0;
out:
if (rc)
free(fp, sizeof(struct file));
return (rc);
}
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], 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);
}
/*
* Copy a portion of a file into kernel memory.
* Cross block boundaries when necessary.
*/
int
ufs_read(f, start, size, resid)
struct open_file *f;
char *start;
u_int size;
u_int *resid; /* out */
{
register struct file *fp = (struct file *)f->f_fsdata;
register u_int csize;
char *buf;
u_int buf_size;
int rc = 0;
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, start, csize);
fp->f_seekp += csize;
start += csize;
size -= csize;
}
if (resid)
*resid = size;
return (rc);
}
/*
* Not implemented.
*/
int
ufs_write(f, start, size, resid)
struct open_file *f;
char *start;
u_int size;
u_int *resid; /* out */
{
return (EROFS);
}
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);
}
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);
}
Continuous source code history from original PDP-7 UNIX to FreeBSD 2, the first fully unencumbered FreeBSD release.