ufs.c revision 7c478bd95313f5f23a4c958a745db2134aa03244
/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License, Version 1.0 only
* (the "License"). You may not use this file except in compliance
* with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright 1991-1994, 2002 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
#pragma ident "%Z%%M% %I% %E% SMI"
/* from "@(#)boot/ufssys.c 1.1 90/03/28 SMI" */
/*
* Basic file system reading code for standalone I/O system.
*/
#include <sys/param.h>
#include <sys/vnode.h>
#include <sys/fs/ufs_fsdir.h>
#include <sys/fs/ufs_fs.h>
#include <sys/fs/ufs_inode.h>
#include "iob.h"
#include "cbootblk.h"
/*
* private definitions of ufs macros from sys/fs/ufs_fs.h
* due to boot block size problems, these macros are coded
* to use the older narrow file offset type (31 bit). This
* saves a lot of code space. Since we will never encounter
* a large file here, it is safe to cast offset_t to off_t.
*/
#define bb_fragroundup(fs, size) /* roundup(size, fs->fs_fsize) */ \
((off_t)((size) + (fs)->fs_fsize - 1) & (off_t)(fs)->fs_fmask)
#define bb_blksize(fs, ip, lbn) \
(((lbn) >= NDADDR || \
(off_t)(ip)->i_size >= (off_t)((lbn) + 1) << (fs)->fs_bshift) \
? (fs)->fs_bsize \
: (bb_fragroundup(fs, blkoff(fs, (off_t)(ip)->i_size))))
#define NULL 0
static struct direct *readdir(struct iob *, int *);
static ino_t dlook(char *, struct iob *);
static int getblock(struct iob *io);
char fscompname[] = "ufsboot";
static struct iob iob[1]; /* only one open file! */
static int
openi(ino_t n, struct iob *io)
{
struct dinode *dp;
struct fs *fs = &io->iob_fs;
io->i_saio.si_offset = 0;
if (devbread(io->i_si, io->i_buf,
fsbtodb(fs, itod(fs, n)), fs->fs_bsize) != fs->fs_bsize)
return (0);
dp = (struct dinode *)io->i_buf;
io->i_ino.i_ic = dp[itoo(fs, n)].di_ic;
return (1);
}
static ino_t
find(char *nm, struct iob *file)
{
char *q;
char c;
ino_t n;
char pathbuf[MAXPATHLEN], *path;
char *link;
size_t linklen;
int fmt = IFDIR;
if (nm == NULL || *nm == '\0')
return (0);
bcopy(nm, pathbuf, strlen(nm) + 1);
root:
path = pathbuf;
if (openi((ino_t)UFSROOTINO, file) == 0)
return (0);
while (*path) {
while (*path == '/')
path++;
q = path;
while (*q != '/' && *q != '\0')
q++;
c = *q;
*q = '\0';
if ((n = dlook(path, file)) != 0) {
*q = c;
if (openi(n, file) == 0)
return (0);
switch (fmt = (file->i_ino.i_smode & IFMT)) {
case IFREG:
case IFDIR:
break;
case IFLNK:
if (getblock(file) != 0)
return (0);
link = (char *)file->i_saio.si_ma;
linklen = strlen(link);
if (*link == '/')
path = pathbuf;
/*
* Copy unprocessed pathname up & prepend link
* (Yes, this bcopy handles overlapping args)
*/
bcopy(q, path + linklen, strlen(q) + 1);
bcopy(link, path, linklen);
path = pathbuf;
goto root;
/*NOTREACHED*/
default:
return (0);
}
if (c == '\0')
break;
path = q;
continue;
} else
return (0);
}
return (fmt == IFREG ? n : 0);
}
static daddr_t
sbmap(struct iob *io, daddr_t bn)
{
struct bnode *ip;
int i, j, sh;
daddr_t nb, *bap;
/* These are the pools of buffers, iob's, etc. */
static union {
char b[NIADDR+1][MAXBSIZE];
daddr_t *dummy; /* force alignment */
} b;
static daddr_t blknos[NIADDR+1];
ip = &io->i_ino;
/*
* blocks 0..NDADDR are direct blocks
*/
if (bn < NDADDR)
return (ip->i_db[bn]);
/*
* addresses NIADDR have single and double indirect blocks.
* the first step is to determine how many levels of indirection.
*/
sh = 1;
bn -= NDADDR;
for (j = NIADDR; j > 0; j--) {
sh *= NINDIR(&io->iob_fs);
if (bn < sh)
break;
bn -= sh;
}
if (j == 0)
return ((daddr_t)0);
/*
* fetch the first indirect block address from the inode
*/
nb = ip->i_ib[NIADDR - j];
if (nb == 0)
return ((daddr_t)0);
/*
* fetch through the indirect blocks
*/
for (; j <= NIADDR; j++) {
if (blknos[j] != nb) {
if (devbread(io->i_si, b.b[j],
fsbtodb(&io->iob_fs, nb),
io->iob_fs.fs_bsize) != io->iob_fs.fs_bsize)
return ((daddr_t)0);
blknos[j] = nb;
}
bap = (daddr_t *)b.b[j];
sh /= NINDIR(&io->iob_fs);
i = (bn / sh) % NINDIR(&io->iob_fs);
nb = bap[i];
if (nb == 0)
return ((daddr_t)0);
}
return (nb);
}
static ino_t
dlook(char *s, struct iob *io)
{
struct direct *dp;
struct bnode *ip;
int len, loc = 0;
ip = &io->i_ino;
if (s == NULL || *s == '\0')
return (0);
if ((ip->i_smode & IFMT) != IFDIR || ip->i_size == 0)
return (0);
len = strlen(s);
for (dp = readdir(io, &loc); dp != NULL; dp = readdir(io, &loc)) {
if (dp->d_ino == 0)
continue;
if (dp->d_namlen == len && strcmp(s, dp->d_name) == 0)
return (dp->d_ino);
}
return (0);
}
/*
* get next entry in a directory.
*/
static struct direct *
readdir(struct iob *io, int *loc_p)
{
struct direct *dp;
daddr_t lbn, d;
int off;
int loc = *loc_p;
int bsize;
for (;;) {
if (loc >= io->i_ino.i_size)
return (NULL);
off = blkoff(&io->iob_fs, loc);
if (off == 0) {
lbn = lblkno(&io->iob_fs, loc);
if ((d = sbmap(io, lbn)) == 0)
return (NULL);
bsize = bb_blksize(&io->iob_fs, &io->i_ino, lbn);
if (devbread(io->i_si, io->i_buf,
fsbtodb(&io->iob_fs, d), bsize) != bsize)
return (NULL);
}
dp = (struct direct *)(io->i_buf + off);
*loc_p = (loc += dp->d_reclen);
if (dp->d_ino == 0)
continue;
return (dp);
}
}
static int
getblock(struct iob *io)
{
struct fs *fs;
int off, size, diff;
daddr_t lbn;
diff = io->i_ino.i_size - io->i_saio.si_offset;
if (diff <= 0)
return (-1);
fs = &io->iob_fs;
lbn = lblkno(fs, io->i_saio.si_offset);
off = blkoff(fs, io->i_saio.si_offset);
size = bb_blksize(fs, &io->i_ino, lbn);
io->i_saio.si_cc = size;
if (devbread(io->i_si, io->i_buf,
fsbtodb(fs, sbmap(io, lbn)), size) != size)
return (-1);
if (io->i_saio.si_offset - off + size >= io->i_ino.i_size)
io->i_saio.si_cc = diff + off;
io->i_saio.si_cc -= off;
io->i_saio.si_ma = &io->i_buf[off];
return (0);
}
int
readfile(int fd, char *buf, int count)
{
struct iob *io = &iob[fd];
int i, j;
if (io->i_saio.si_offset + count > io->i_ino.i_size)
count = io->i_ino.i_size - io->i_saio.si_offset;
if ((i = count) <= 0)
return (0);
while (i > 0) {
if (io->i_saio.si_cc <= 0) {
if (getblock(io) == -1)
return (0);
}
j = (i < io->i_saio.si_cc) ? i : io->i_saio.si_cc;
bcopy(io->i_saio.si_ma, buf, (size_t)j);
buf += j;
io->i_saio.si_ma += j;
io->i_saio.si_offset += j;
io->i_saio.si_cc -= j;
i -= j;
}
return (count);
}
/*
* Open a file.
*/
int
openfile(char *device, char *pathname)
{
struct iob *io = &iob[0]; /* only one open file! */
io->i_ino.i_dev = 0;
if ((io->i_si = devopen(device)) == NULL)
return (-1); /* if devopen fails, open fails */
/* Pseudo-mount a file system; read the superblock. */
if (devbread(io->i_si, &io->iob_fs, SBLOCK, SBSIZE) != SBSIZE)
goto failed;
if (io->iob_fs.fs_magic != FS_MAGIC) {
puts("bootblk: not a UFS file system.\n");
goto failed;
}
if (find(pathname, io) == 0)
goto failed;
io->i_saio.si_offset = io->i_saio.si_cc = 0;
return (0); /* only one open file! */
failed:
(void) devclose(io->i_si);
return (-1);
}
int
closefile(int fd)
{
struct iob *io = &iob[fd];
return (devclose(io->i_si));
}
/*
* This version of seek() only performs absolute seeks (whence == 0).
*/
void
seekfile(int fd, off_t addr)
{
struct iob *io = &iob[fd];
io->i_saio.si_offset = addr;
io->i_saio.si_cc = 0;
}