OpenSolaris_b135/grub/grub-0.97/stage2/fsys_minix.c
/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 1999,2000,2001,2002 Free Software Foundation, Inc.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
/* Restrictions:
This is MINIX V1 only (yet)
Disk creation is like:
mkfs.minix -c DEVICE
*/
#ifdef FSYS_MINIX
#include "shared.h"
#include "filesys.h"
/* #define DEBUG_MINIX */
/* indirect blocks */
static int mapblock1, mapblock2, namelen;
/* sizes are always in bytes, BLOCK values are always in DEV_BSIZE (sectors) */
#define DEV_BSIZE 512
/* include/linux/fs.h */
#define BLOCK_SIZE_BITS 10
#define BLOCK_SIZE (1<<BLOCK_SIZE_BITS)
/* made up, defaults to 1 but can be passed via mount_opts */
#define WHICH_SUPER 1
/* kind of from fs/ext2/super.c (is OK for minix) */
#define SBLOCK (WHICH_SUPER * BLOCK_SIZE / DEV_BSIZE) /* = 2 */
/* include/asm-i386/type.h */
typedef __signed__ char __s8;
typedef unsigned char __u8;
typedef __signed__ short __s16;
typedef unsigned short __u16;
typedef __signed__ int __s32;
typedef unsigned int __u32;
/* include/linux/minix_fs.h */
#define MINIX_ROOT_INO 1
/* Not the same as the bogus LINK_MAX in <linux/limits.h>. Oh well. */
#define MINIX_LINK_MAX 250
#define MINIX2_LINK_MAX 65530
#define MINIX_I_MAP_SLOTS 8
#define MINIX_Z_MAP_SLOTS 64
#define MINIX_SUPER_MAGIC 0x137F /* original minix fs */
#define MINIX_SUPER_MAGIC2 0x138F /* minix fs, 30 char names */
#define MINIX2_SUPER_MAGIC 0x2468 /* minix V2 fs */
#define MINIX2_SUPER_MAGIC2 0x2478 /* minix V2 fs, 30 char names */
#define MINIX_VALID_FS 0x0001 /* Clean fs. */
#define MINIX_ERROR_FS 0x0002 /* fs has errors. */
#define MINIX_INODES_PER_BLOCK ((BLOCK_SIZE)/(sizeof (struct minix_inode)))
#define MINIX2_INODES_PER_BLOCK ((BLOCK_SIZE)/(sizeof (struct minix2_inode)))
#define MINIX_V1 0x0001 /* original minix fs */
#define MINIX_V2 0x0002 /* minix V2 fs */
/* originally this is :
#define INODE_VERSION(inode) inode->i_sb->u.minix_sb.s_version
here we have */
#define INODE_VERSION(inode) (SUPERBLOCK->s_version)
/*
* This is the original minix inode layout on disk.
* Note the 8-bit gid and atime and ctime.
*/
struct minix_inode {
__u16 i_mode;
__u16 i_uid;
__u32 i_size;
__u32 i_time;
__u8 i_gid;
__u8 i_nlinks;
__u16 i_zone[9];
};
/*
* The new minix inode has all the time entries, as well as
* long block numbers and a third indirect block (7+1+1+1
* instead of 7+1+1). Also, some previously 8-bit values are
* now 16-bit. The inode is now 64 bytes instead of 32.
*/
struct minix2_inode {
__u16 i_mode;
__u16 i_nlinks;
__u16 i_uid;
__u16 i_gid;
__u32 i_size;
__u32 i_atime;
__u32 i_mtime;
__u32 i_ctime;
__u32 i_zone[10];
};
/*
* minix super-block data on disk
*/
struct minix_super_block {
__u16 s_ninodes;
__u16 s_nzones;
__u16 s_imap_blocks;
__u16 s_zmap_blocks;
__u16 s_firstdatazone;
__u16 s_log_zone_size;
__u32 s_max_size;
__u16 s_magic;
__u16 s_state;
__u32 s_zones;
};
struct minix_dir_entry {
__u16 inode;
char name[0];
};
/* made up, these are pointers into FSYS_BUF */
/* read once, always stays there: */
#define SUPERBLOCK \
((struct minix_super_block *)(FSYS_BUF))
#define INODE \
((struct minix_inode *)((int) SUPERBLOCK + BLOCK_SIZE))
#define DATABLOCK1 \
((int)((int)INODE + sizeof(struct minix_inode)))
#define DATABLOCK2 \
((int)((int)DATABLOCK1 + BLOCK_SIZE))
/* linux/stat.h */
#define S_IFMT 00170000
#define S_IFLNK 0120000
#define S_IFREG 0100000
#define S_IFDIR 0040000
#define S_ISLNK(m) (((m) & S_IFMT) == S_IFLNK)
#define S_ISREG(m) (((m) & S_IFMT) == S_IFREG)
#define S_ISDIR(m) (((m) & S_IFMT) == S_IFDIR)
#define PATH_MAX 1024 /* include/linux/limits.h */
#define MAX_LINK_COUNT 5 /* number of symbolic links to follow */
/* check filesystem types and read superblock into memory buffer */
int
minix_mount (void)
{
if (((current_drive & 0x80) || current_slice != 0)
&& ! IS_PC_SLICE_TYPE_MINIX (current_slice)
&& ! IS_PC_SLICE_TYPE_BSD_WITH_FS (current_slice, FS_OTHER))
return 0; /* The partition is not of MINIX type */
if (part_length < (SBLOCK +
(sizeof (struct minix_super_block) / DEV_BSIZE)))
return 0; /* The partition is too short */
if (!devread (SBLOCK, 0, sizeof (struct minix_super_block),
(char *) SUPERBLOCK))
return 0; /* Cannot read superblock */
switch (SUPERBLOCK->s_magic)
{
case MINIX_SUPER_MAGIC:
namelen = 14;
break;
case MINIX_SUPER_MAGIC2:
namelen = 30;
break;
default:
return 0; /* Unsupported type */
}
return 1;
}
/* Takes a file system block number and reads it into BUFFER. */
static int
minix_rdfsb (int fsblock, int buffer)
{
return devread (fsblock * (BLOCK_SIZE / DEV_BSIZE), 0,
BLOCK_SIZE, (char *) buffer);
}
/* Maps LOGICAL_BLOCK (the file offset divided by the blocksize) into
a physical block (the location in the file system) via an inode. */
static int
minix_block_map (int logical_block)
{
int i;
if (logical_block < 7)
return INODE->i_zone[logical_block];
logical_block -= 7;
if (logical_block < 512)
{
i = INODE->i_zone[7];
if (!i || ((mapblock1 != 1)
&& !minix_rdfsb (i, DATABLOCK1)))
{
errnum = ERR_FSYS_CORRUPT;
return -1;
}
mapblock1 = 1;
return ((__u16 *) DATABLOCK1) [logical_block];
}
logical_block -= 512;
i = INODE->i_zone[8];
if (!i || ((mapblock1 != 2)
&& !minix_rdfsb (i, DATABLOCK1)))
{
errnum = ERR_FSYS_CORRUPT;
return -1;
}
mapblock1 = 2;
i = ((__u16 *) DATABLOCK1)[logical_block >> 9];
if (!i || ((mapblock2 != i)
&& !minix_rdfsb (i, DATABLOCK2)))
{
errnum = ERR_FSYS_CORRUPT;
return -1;
}
mapblock2 = i;
return ((__u16 *) DATABLOCK2)[logical_block & 511];
}
/* read from INODE into BUF */
int
minix_read (char *buf, int len)
{
int logical_block;
int offset;
int map;
int ret = 0;
int size = 0;
while (len > 0)
{
/* find the (logical) block component of our location */
logical_block = filepos >> BLOCK_SIZE_BITS;
offset = filepos & (BLOCK_SIZE - 1);
map = minix_block_map (logical_block);
#ifdef DEBUG_MINIX
printf ("map=%d\n", map);
#endif
if (map < 0)
break;
size = BLOCK_SIZE;
size -= offset;
if (size > len)
size = len;
disk_read_func = disk_read_hook;
devread (map * (BLOCK_SIZE / DEV_BSIZE),
offset, size, buf);
disk_read_func = NULL;
buf += size;
len -= size;
filepos += size;
ret += size;
}
if (errnum)
ret = 0;
return ret;
}
/* preconditions: minix_mount already executed, therefore supblk in buffer
known as SUPERBLOCK
returns: 0 if error, nonzero iff we were able to find the file successfully
postconditions: on a nonzero return, buffer known as INODE contains the
inode of the file we were trying to look up
side effects: none yet */
int
minix_dir (char *dirname)
{
int current_ino = MINIX_ROOT_INO; /* start at the root */
int updir_ino = current_ino; /* the parent of the current directory */
int ino_blk; /* fs pointer of the inode's info */
int str_chk = 0; /* used ot hold the results of a string
compare */
struct minix_inode * raw_inode; /* inode info for current_ino */
char linkbuf[PATH_MAX]; /* buffer for following sym-links */
int link_count = 0;
char * rest;
char ch;
int off; /* offset within block of directory
entry */
int loc; /* location within a directory */
int blk; /* which data blk within dir entry */
long map; /* fs pointer of a particular block from
dir entry */
struct minix_dir_entry * dp; /* pointer to directory entry */
/* loop invariants:
current_ino = inode to lookup
dirname = pointer to filename component we are cur looking up within
the directory known pointed to by current_ino (if any) */
#ifdef DEBUG_MINIX
printf ("\n");
#endif
while (1)
{
#ifdef DEBUG_MINIX
printf ("inode %d, dirname %s\n", current_ino, dirname);
#endif
ino_blk = (2 + SUPERBLOCK->s_imap_blocks + SUPERBLOCK->s_zmap_blocks
+ (current_ino - 1) / MINIX_INODES_PER_BLOCK);
if (! minix_rdfsb (ino_blk, (int) INODE))
return 0;
/* reset indirect blocks! */
mapblock2 = mapblock1 = -1;
raw_inode = INODE + ((current_ino - 1) % MINIX_INODES_PER_BLOCK);
/* copy inode to fixed location */
memmove ((void *) INODE, (void *) raw_inode,
sizeof (struct minix_inode));
/* If we've got a symbolic link, then chase it. */
if (S_ISLNK (INODE->i_mode))
{
int len;
if (++link_count > MAX_LINK_COUNT)
{
errnum = ERR_SYMLINK_LOOP;
return 0;
}
#ifdef DEBUG_MINIX
printf ("S_ISLNK (%s)\n", dirname);
#endif
/* Find out how long our remaining name is. */
len = 0;
while (dirname[len] && !isspace (dirname[len]))
len++;
/* Get the symlink size. */
filemax = (INODE->i_size);
if (filemax + len > sizeof (linkbuf) - 2)
{
errnum = ERR_FILELENGTH;
return 0;
}
if (len)
{
/* Copy the remaining name to the end of the symlink data.
Note that DIRNAME and LINKBUF may overlap! */
memmove (linkbuf + filemax, dirname, len);
}
linkbuf[filemax + len] = '\0';
/* Read the necessary blocks, and reset the file pointer. */
len = grub_read (linkbuf, filemax);
filepos = 0;
if (!len)
return 0;
#ifdef DEBUG_MINIX
printf ("symlink=%s\n", linkbuf);
#endif
dirname = linkbuf;
if (*dirname == '/')
{
/* It's an absolute link, so look it up in root. */
current_ino = MINIX_ROOT_INO;
updir_ino = current_ino;
}
else
{
/* Relative, so look it up in our parent directory. */
current_ino = updir_ino;
}
/* Try again using the new name. */
continue;
}
/* If end of filename, INODE points to the file's inode */
if (!*dirname || isspace (*dirname))
{
if (!S_ISREG (INODE->i_mode))
{
errnum = ERR_BAD_FILETYPE;
return 0;
}
filemax = (INODE->i_size);
return 1;
}
/* else we have to traverse a directory */
updir_ino = current_ino;
/* skip over slashes */
while (*dirname == '/')
dirname++;
/* if this isn't a directory of sufficient size to hold our file,
abort */
if (!(INODE->i_size) || !S_ISDIR (INODE->i_mode))
{
errnum = ERR_BAD_FILETYPE;
return 0;
}
/* skip to next slash or end of filename (space) */
for (rest = dirname; (ch = *rest) && !isspace (ch) && ch != '/';
rest++);
/* look through this directory and find the next filename component */
/* invariant: rest points to slash after the next filename component */
*rest = 0;
loc = 0;
do
{
#ifdef DEBUG_MINIX
printf ("dirname=`%s', rest=`%s', loc=%d\n", dirname, rest, loc);
#endif
/* if our location/byte offset into the directory exceeds the size,
give up */
if (loc >= INODE->i_size)
{
if (print_possibilities < 0)
{
#if 0
putchar ('\n');
#endif
}
else
{
errnum = ERR_FILE_NOT_FOUND;
*rest = ch;
}
return (print_possibilities < 0);
}
/* else, find the (logical) block component of our location */
blk = loc >> BLOCK_SIZE_BITS;
/* we know which logical block of the directory entry we are looking
for, now we have to translate that to the physical (fs) block on
the disk */
map = minix_block_map (blk);
#ifdef DEBUG_MINIX
printf ("fs block=%d\n", map);
#endif
mapblock2 = -1;
if ((map < 0) || !minix_rdfsb (map, DATABLOCK2))
{
errnum = ERR_FSYS_CORRUPT;
*rest = ch;
return 0;
}
off = loc & (BLOCK_SIZE - 1);
dp = (struct minix_dir_entry *) (DATABLOCK2 + off);
/* advance loc prematurely to next on-disk directory entry */
loc += sizeof (dp->inode) + namelen;
/* NOTE: minix filenames are NULL terminated if < NAMELEN
else exact */
#ifdef DEBUG_MINIX
printf ("directory entry ino=%d\n", dp->inode);
if (dp->inode)
printf ("entry=%s\n", dp->name);
#endif
if (dp->inode)
{
int saved_c = dp->name[namelen];
dp->name[namelen] = 0;
str_chk = substring (dirname, dp->name);
# ifndef STAGE1_5
if (print_possibilities && ch != '/'
&& (!*dirname || str_chk <= 0))
{
if (print_possibilities > 0)
print_possibilities = -print_possibilities;
print_a_completion (dp->name);
}
# endif
dp->name[namelen] = saved_c;
}
}
while (!dp->inode || (str_chk || (print_possibilities && ch != '/')));
current_ino = dp->inode;
*(dirname = rest) = ch;
}
/* never get here */
}
#endif /* FSYS_MINIX */