URL https://opencores.org/ocsvn/or1k/or1k/trunk

Subversion Repositories or1k

[/] [or1k/] [trunk/] [uclinux/] [uClinux-2.0.x/] [fs/] [romfs/] [inode.c] - Blame information for rev 199

Go to most recent revision | Details | Compare with Previous | View Log


/*
 * ROMFS file system, Linux implementation
 *
 * Copyright (C) 1997  Janos Farkas <chexum@shadow.banki.hu>
 *
 * Using parts of the minix filesystem
 * Copyright (C) 1991, 1992  Linus Torvalds
 *
 * and parts of the affs filesystem additionally
 * Copyright (C) 1993  Ray Burr
 * Copyright (C) 1996  Hans-Joachim Widmaier
 *
 * 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.
 *
 * Changes
 *                                      Changed for 2.1.19 modules
 *      Jan 1997                        Initial release
 *      Nov 1997        2.0.32          Merging applicable 2.1 bugfixes
 *
 */
 
/* todo:
 *      - see Documentation/filesystems/romfs.txt
 *      - use malloced memory for file names?
 *      - quicklist routines from fs/namei.c, get_page is possibly not
 *        intended to be used now
 *      - considering write access...
 *      - network (tftp) files?
 *      - in the ancient times something leaked to made umounts
 *        impossible, but I've not seen it in the last months
 */
 
/*
 * Sorry about some optimizations and for some goto's.  I just wanted
 * to squeeze some more bytes out of this code.. :)
 */
 
#include <linux/module.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/malloc.h>
#include <linux/romfs_fs.h>
#include <linux/fs.h>
#include <linux/locks.h>
 
#include <asm/byteorder.h>
 
static int inline min(int a, int b)
{
        return a<b ? a : b;
}
 
static __s32
romfs_checksum(void *data, int size)
{
        __s32 sum, *ptr;
 
        sum = 0; ptr = data;
        size>>=2;
        while (size>0) {
                sum += ntohl(*ptr++);
                size--;
        }
        return sum;
}
 
static struct super_operations romfs_ops;
 
static struct super_block *
romfs_read_super(struct super_block *s, void *data, int silent)
{
        struct buffer_head *bh;
        kdev_t dev = s->s_dev;
        struct romfs_super_block *rsb;
        int sz;
 
        MOD_INC_USE_COUNT;
 
        /* I would parse the options here, but there are none.. :) */
 
        lock_super(s);
        set_blocksize(dev, ROMBSIZE);
        s->s_blocksize = ROMBSIZE;
        s->s_blocksize_bits = ROMBSBITS;
        bh = bread(dev, 0, ROMBSIZE);
        if (!bh) {
                /* XXX merge with other printk? */
                printk ("romfs: unable to read superblock\n");
                goto outnobh;
        }
 
        rsb = (struct romfs_super_block *)bh->b_data;
        sz = ntohl(rsb->size);
        if (rsb->word0 != ROMSB_WORD0 || rsb->word1 != ROMSB_WORD1
           || sz < ROMFH_SIZE) {
                if (!silent)
                        printk ("VFS: Can't find a romfs filesystem on dev "
                                "%s.\n", kdevname(dev));
                goto out;
        }
        if (romfs_checksum(rsb, min(sz,512))) {
                printk ("romfs: bad initial checksum on dev "
                        "%s.\n", kdevname(dev));
                goto out;
        }
 
        s->s_magic = ROMFS_MAGIC;
        s->u.romfs_sb.s_maxsize = sz;
 
        s->s_flags |= MS_RDONLY;
 
        /* Find the start of the fs */
        sz = (ROMFH_SIZE +
              strnlen(rsb->name, ROMFS_MAXFN) + 1 + ROMFH_PAD)
             & ROMFH_MASK;
 
        brelse(bh);
 
        s->s_op = &romfs_ops;
 
        if (!(s->s_mounted = iget(s, sz)))
                goto outnobh;
 
        unlock_super(s);
 
        /* Ehrhm; sorry.. :)  And thanks to Hans-Joachim Widmaier  :) */
        if (0) {
out:
                brelse(bh);
outnobh:
                s->s_dev = 0;
                unlock_super(s);
                MOD_DEC_USE_COUNT;
                s = NULL;
        }
 
        return s;
}
 
/* Nothing to do.. */
 
static void
romfs_put_super(struct super_block *sb)
{
        lock_super(sb);
        sb->s_dev = 0;
        unlock_super(sb);
        MOD_DEC_USE_COUNT;
        return;
}
 
/* That's simple too. */
 
static void
romfs_statfs(struct super_block *sb, struct statfs *buf, int bufsize)
{
        struct statfs tmp;
 
        memset(&tmp, 0, sizeof(tmp));
        tmp.f_type = ROMFS_MAGIC;
        tmp.f_bsize = ROMBSIZE;
        tmp.f_blocks = (sb->u.romfs_sb.s_maxsize+ROMBSIZE-1)>>ROMBSBITS;
        memcpy_tofs(buf, &tmp, bufsize);
}
 
/* some helper routines */
 
static int
romfs_strnlen(struct inode *i, unsigned long offset, unsigned long count)
{
        struct buffer_head *bh;
        unsigned long avail, maxsize, res;
 
        maxsize = i->i_sb->u.romfs_sb.s_maxsize;
        if (offset >= maxsize)
                return -1;
 
        /* strnlen is almost always valid */
        if (count > maxsize || offset+count > maxsize)
                count = maxsize-offset;
 
        bh = bread(i->i_dev, offset>>ROMBSBITS, ROMBSIZE);
        if (!bh)
                return -1;              /* error */
 
        avail = ROMBSIZE - (offset & ROMBMASK);
        maxsize = min(count, avail);
        res = strnlen(((char *)bh->b_data)+(offset&ROMBMASK), maxsize);
        brelse(bh);
 
        if (res < maxsize)
                return res;             /* found all of it */
 
        while (res < count) {
                offset += maxsize;
 
                bh = bread(i->i_dev, offset>>ROMBSBITS, ROMBSIZE);
                if (!bh)
                        return -1;
                maxsize = min(count-res, ROMBSIZE);
                avail = strnlen(bh->b_data, maxsize);
                res += avail;
                brelse(bh);
                if (avail < maxsize)
                        return res;
        }
        return res;
}
 
static int
romfs_copyfrom(struct inode *i, void *dest, unsigned long offset, unsigned long count)
{
        struct buffer_head *bh;
        unsigned long avail, maxsize, res;
 
        maxsize = i->i_sb->u.romfs_sb.s_maxsize;
        if (offset >= maxsize || count > maxsize || offset+count>maxsize)
                return -1;
 
        bh = bread(i->i_dev, offset>>ROMBSBITS, ROMBSIZE);
        if (!bh)
                return -1;              /* error */
 
        avail = ROMBSIZE - (offset & ROMBMASK);
        maxsize = min(count, avail);
        memcpy(dest, ((char *)bh->b_data) + (offset & ROMBMASK), maxsize);
        brelse(bh);
 
        res = maxsize;                  /* all of it */
 
        while (res < count) {
                offset += maxsize;
                dest += maxsize;
 
                bh = bread(i->i_dev, offset>>ROMBSBITS, ROMBSIZE);
                if (!bh)
                        return -1;
                maxsize = min(count-res, ROMBSIZE);
                memcpy(dest, bh->b_data, maxsize);
                brelse(bh);
                res += maxsize;
        }
        return res;
}
 
/* Directory operations */
 
static int
romfs_readdir(struct inode *i, struct file *filp, void *dirent, filldir_t filldir)
{
        struct romfs_inode ri;
        unsigned long offset, maxoff;
        int j, ino, nextfh;
        int stored = 0;
        char fsname[ROMFS_MAXFN];       /* XXX dynamic? */
 
        if (!i || !S_ISDIR(i->i_mode))
                return -EBADF;
 
        maxoff = i->i_sb->u.romfs_sb.s_maxsize;
 
        offset = filp->f_pos;
        if (!offset) {
                offset = i->i_ino & ROMFH_MASK;
                if (romfs_copyfrom(i, &ri, offset, ROMFH_SIZE) <= 0)
                        return stored;
                offset = ntohl(ri.spec) & ROMFH_MASK;
        }
 
        /* Not really failsafe, but we are read-only... */
        for(;;) {
                if (!offset || offset >= maxoff) {
                        offset = 0xffffffff;
                        filp->f_pos = offset;
                        return stored;
                }
                filp->f_pos = offset;
 
                /* Fetch inode info */
                if (romfs_copyfrom(i, &ri, offset, ROMFH_SIZE) <= 0)
                        return stored;
 
                j = romfs_strnlen(i, offset+ROMFH_SIZE, sizeof(fsname)-1);
                if (j < 0)
                        return stored;
 
                fsname[j]=0;
                romfs_copyfrom(i, fsname, offset+ROMFH_SIZE, j);
 
                ino = offset;
                nextfh = ntohl(ri.next);
                if ((nextfh & ROMFH_TYPE) == ROMFH_HRD)
                        ino = ntohl(ri.spec);
                if (filldir(dirent, fsname, j, offset, ino) < 0) {
                        return stored;
                }
                stored++;
                offset = nextfh & ROMFH_MASK;
        }
}
 
static int
romfs_lookup(struct inode *dir, const char *name, int len, struct inode **result)
{
        unsigned long offset, maxoff;
        int fslen, res;
        char fsname[ROMFS_MAXFN];       /* XXX dynamic? */
        struct romfs_inode ri;
 
        *result = NULL;
        if (!dir || !S_ISDIR(dir->i_mode)) {
                res = -EBADF;
                goto out;
        }
 
        offset = dir->i_ino & ROMFH_MASK;
        if (romfs_copyfrom(dir, &ri, offset, ROMFH_SIZE) <= 0) {
                res = -ENOENT;
                goto out;
        }
 
        maxoff = dir->i_sb->u.romfs_sb.s_maxsize;
        offset = ntohl(ri.spec) & ROMFH_MASK;
 
        for(;;) {
                if (!offset || offset >= maxoff
                    || romfs_copyfrom(dir, &ri, offset, ROMFH_SIZE) <= 0) {
                        res = -ENOENT;
                        goto out;
                }
 
                /* try to match the first 16 bytes of name */
                fslen = romfs_strnlen(dir, offset+ROMFH_SIZE, ROMFH_SIZE);
                if (len < ROMFH_SIZE) {
                        if (len == fslen) {
                                /* both are shorter, and same size */
                                romfs_copyfrom(dir, fsname, offset+ROMFH_SIZE, len+1);
                                if (strncmp (name, fsname, len) == 0)
                                        break;
                        }
                } else if (fslen >= ROMFH_SIZE) {
                        /* both are longer; XXX optimize max size */
                        fslen = romfs_strnlen(dir, offset+ROMFH_SIZE, sizeof(fsname)-1);
                        if (len == fslen) {
                                romfs_copyfrom(dir, fsname, offset+ROMFH_SIZE, len+1);
                                if (strncmp(name, fsname, len) == 0)
                                        break;
                        }
                }
                /* next entry */
                offset = ntohl(ri.next) & ROMFH_MASK;
        }
 
        /* Hard link handling */
        if ((ntohl(ri.next) & ROMFH_TYPE) == ROMFH_HRD)
                offset = ntohl(ri.spec) & ROMFH_MASK;
 
        res = 0;
        if (!(*result = iget(dir->i_sb, offset)))
                res = -EACCES;
 
out:
        iput(dir);
        return res;
}
 
/*
 * Ok, we do readpage, to be able to execute programs.  Unfortunately,
 * we can't use bmap, since we have looser alignments.
 */
 
static int
romfs_readpage(struct inode * inode, struct page * page)
{
        unsigned long buf;
        unsigned long offset, avail, readlen;
        int result = -EIO;
 
        page->count++;
        set_bit(PG_locked, &page->flags);
 
        buf = page_address(page);
        clear_bit(PG_uptodate, &page->flags);
        clear_bit(PG_error, &page->flags);
        offset = page->offset;
        if (offset < inode->i_size) {
                avail = inode->i_size-offset;
                readlen = min(avail, PAGE_SIZE);
                if (romfs_copyfrom(inode, (void *)buf, inode->u.romfs_i.i_dataoffset+offset, readlen) == readlen) {
                        if (readlen < PAGE_SIZE) {
                                memset((void *)(buf+readlen),0,PAGE_SIZE-readlen);
                        }
                        set_bit(PG_uptodate, &page->flags);
                        result = 0;
                }
        }
        if (result) {
                set_bit(PG_error, &page->flags);
                memset((void *)buf, 0, PAGE_SIZE);
        }
 
        clear_bit(PG_locked, &page->flags);
        wake_up(&page->wait);
        free_page(buf);
 
        return result;
}
 
#ifdef MAGIC_ROM_PTR
static int
romfs_romptr(struct inode * inode, struct file * filp, struct vm_area_struct * vma)
{
        vma->vm_offset += inode->u.romfs_i.i_dataoffset;
 
        if ((vma->vm_flags & VM_WRITE) || bromptr(inode->i_dev, vma))
                return -ENOSYS;
 
        return 0;
}
#endif
 
static int
romfs_readlink(struct inode *inode, char *buffer, int len)
{
        int mylen;
        char buf[ROMFS_MAXFN];          /* XXX dynamic */
 
        if (!inode || !S_ISLNK(inode->i_mode)) {
                mylen = -EBADF;
                goto out;
        }
 
        mylen = min(sizeof(buf), inode->i_size);
 
        if (romfs_copyfrom(inode, buf, inode->u.romfs_i.i_dataoffset, mylen) <= 0) {
                mylen = -EIO;
                goto out;
        }
        memcpy_tofs(buffer, buf, mylen);
 
out:
        iput(inode);
        return mylen;
}
 
static int
romfs_follow_link(struct inode *dir, struct inode *inode,
        int flag, int mode, struct inode **res_inode)
{
        int error, len;
        char *buf;
 
        *res_inode = NULL;
        if (!dir) {
                dir = current->fs->root;
                dir->i_count++;
        }
 
        if (!inode) {
                iput(dir);
                return -ENOENT;
        }
        if (!S_ISLNK(inode->i_mode)) {
                *res_inode = inode;
                iput(dir);
                return 0;
        }
        if (current->link_count > 5) {
                iput(inode);
                iput(dir);
                return -ELOOP;
        }
 
        /* Eek. Short enough. */
        len = inode->i_size;
        if (!(buf = kmalloc(len+1, GFP_KERNEL))) {
                iput(inode);
                iput(dir);
                /* correct?  spin? */
                return -EAGAIN;
        }
        error = romfs_copyfrom(inode, buf, inode->u.romfs_i.i_dataoffset, len);
        if (error != len) {
                iput(inode);
                iput(dir);
                error = -EIO;
        } else {
                iput(inode);
                buf[len] = 0;
                current->link_count++;
                error = open_namei(buf, flag, mode, res_inode, dir);
                current->link_count--;
        }
 
        kfree(buf);
        return error;
}
 
/* Mapping from our types to the kernel */
 
static struct file_operations romfs_file_operations = {
        NULL,                   /* lseek - default */
        generic_file_read,      /* read */
        NULL,                   /* write - bad */
        NULL,                   /* readdir */
        NULL,                   /* select - default */
        NULL,                   /* ioctl */
        generic_file_mmap,      /* mmap */
        NULL,                   /* open */
        NULL,                   /* release */
        NULL,                   /* fsync */
        NULL,                   /* fasync */
        NULL,                   /* check_media_change */
        NULL,                   /* revalidate */
#ifdef MAGIC_ROM_PTR
        romfs_romptr,           /* romptr */
#endif
};
 
static struct inode_operations romfs_file_inode_operations = {
        &romfs_file_operations,
        NULL,                   /* create */
        NULL,                   /* lookup */
        NULL,                   /* link */
        NULL,                   /* unlink */
        NULL,                   /* symlink */
        NULL,                   /* mkdir */
        NULL,                   /* rmdir */
        NULL,                   /* mknod */
        NULL,                   /* rename */
        NULL,                   /* readlink */
        NULL,                   /* follow_link */
        romfs_readpage,         /* readpage */
        NULL,                   /* writepage */
        NULL,                   /* bmap -- not really */
        NULL,                   /* truncate */
        NULL,                   /* permission */
        NULL,                   /* smap */
};
 
static struct file_operations romfs_dir_operations = {
        NULL,                   /* lseek - default */
        NULL,                   /* read */
        NULL,                   /* write - bad */
        romfs_readdir,          /* readdir */
        NULL,                   /* select - default */
        NULL,                   /* ioctl */
        NULL,                   /* mmap */
        NULL,                   /* open */
        NULL,                   /* release */
        NULL,                   /* fsync */
        NULL,                   /* fasync */
        NULL,                   /* check_media_change */
        NULL                    /* revalidate */
};
 
/* Merged dir/symlink op table.  readdir/lookup/readlink/follow_link
 * will protect from type mismatch.
 */
 
static struct inode_operations romfs_dirlink_inode_operations = {
        &romfs_dir_operations,
        NULL,                   /* create */
        romfs_lookup,           /* lookup */
        NULL,                   /* link */
        NULL,                   /* unlink */
        NULL,                   /* symlink */
        NULL,                   /* mkdir */
        NULL,                   /* rmdir */
        NULL,                   /* mknod */
        NULL,                   /* rename */
        romfs_readlink,         /* readlink */
        romfs_follow_link,      /* follow_link */
        NULL,                   /* readpage */
        NULL,                   /* writepage */
        NULL,                   /* bmap */
        NULL,                   /* truncate */
        NULL,                   /* permission */
        NULL,                   /* smap */
};
 
static mode_t romfs_modemap[] =
{
        0, S_IFDIR, S_IFREG, S_IFLNK+0777,
        S_IFBLK, S_IFCHR, S_IFSOCK, S_IFIFO
};
 
static struct inode_operations *romfs_inoops[] =
{
        NULL,                           /* hardlink, handled elsewhere */
        &romfs_dirlink_inode_operations,
        &romfs_file_inode_operations,
        &romfs_dirlink_inode_operations,
        &blkdev_inode_operations,       /* standard handlers */
        &chrdev_inode_operations,
        NULL,                           /* socket */
        NULL,                           /* fifo */
};
 
static void
romfs_read_inode(struct inode *i)
{
        int nextfh, ino;
        struct romfs_inode ri;
 
        ino = i->i_ino & ROMFH_MASK;
 
        i->i_op = NULL;
        i->i_mode = 0;
 
        /* Loop for finding the real hard link */
        for(;;) {
                if (romfs_copyfrom(i, &ri, ino, ROMFH_SIZE) <= 0) {
                        printk("romfs: read error for inode 0x%x\n", ino);
                        return;
                }
                /* XXX: do romfs_checksum here too (with name) */
 
                nextfh = ntohl(ri.next);
                if ((nextfh & ROMFH_TYPE) != ROMFH_HRD)
                        break;
 
                ino = ntohl(ri.spec) & ROMFH_MASK;
        }
 
        i->i_nlink = 1;         /* Hard to decide.. */
        i->i_size = ntohl(ri.size);
        i->i_mtime = i->i_atime = i->i_ctime = 0;
        i->i_uid = i->i_gid = 0;
 
        i->i_op = romfs_inoops[nextfh & ROMFH_TYPE];
 
        /* Precalculate the data offset */
        ino = romfs_strnlen(i, ino+ROMFH_SIZE, ROMFS_MAXFN);
        if (ino >= 0)
                ino = ((ROMFH_SIZE+ino+1+ROMFH_PAD)&ROMFH_MASK);
        else
                ino = 0;
 
        i->u.romfs_i.i_metasize = ino;
        i->u.romfs_i.i_dataoffset = ino+(i->i_ino&ROMFH_MASK);
 
        /* Compute permissions */
        ino = S_IRUGO|S_IWUSR;
        ino |= romfs_modemap[nextfh & ROMFH_TYPE];
        if (nextfh & ROMFH_EXEC) {
                ino |= S_IXUGO;
        }
        i->i_mode = ino;
 
        if (S_ISFIFO(ino))
                init_fifo(i);
        else if (S_ISDIR(ino))
                i->i_size = i->u.romfs_i.i_metasize;
        else if (S_ISBLK(ino) || S_ISCHR(ino)) {
                i->i_mode &= ~(S_IRWXG|S_IRWXO);
                ino = ntohl(ri.spec);
                i->i_rdev = MKDEV(ino>>16,ino&0xffff);
        }
}
 
static struct super_operations romfs_ops = {
        romfs_read_inode,       /* read inode */
        NULL,                   /* notify change */
        NULL,                   /* write inode */
        NULL,                   /* put inode */
        romfs_put_super,        /* put super */
        NULL,                   /* write super */
        romfs_statfs,           /* statfs */
        NULL                    /* remount */
};
 
static struct file_system_type romfs_fs_type = {
        romfs_read_super, "romfs", 1, NULL
};
 
int
init_romfs_fs(void)
{
        return register_filesystem(&romfs_fs_type);
}
 
#ifdef MODULE
 
/* Yes, works even as a module... :) */
 
int
init_module(void)
{
        int status;
 
        if ((status = init_romfs_fs()) == 0)
                register_symtab(0);
        return status;
}
 
void
cleanup_module(void)
{
        unregister_filesystem(&romfs_fs_type);
}
#endif

Browse

Tools

Subversion Repositories or1k

[/] [or1k/] [trunk/] [uclinux/] [uClinux-2.0.x/] [fs/] [romfs/] [inode.c] - Blame information for rev 199

Line No.	Rev	Author	Line
1	199	simons	`/*`
2			`* ROMFS file system, Linux implementation`
3			`*`
4			`* Copyright (C) 1997 Janos Farkas <chexum@shadow.banki.hu>`
5			`*`
6			`* Using parts of the minix filesystem`
7			`* Copyright (C) 1991, 1992 Linus Torvalds`
8			`*`
9			`* and parts of the affs filesystem additionally`
10			`* Copyright (C) 1993 Ray Burr`
11			`* Copyright (C) 1996 Hans-Joachim Widmaier`
12			`*`
13			`* This program is free software; you can redistribute it and/or`
14			`* modify it under the terms of the GNU General Public License`
15			`* as published by the Free Software Foundation; either version`
16			`* 2 of the License, or (at your option) any later version.`
17			`*`
18			`* Changes`
19			`* Changed for 2.1.19 modules`
20			`* Jan 1997 Initial release`
21			`* Nov 1997 2.0.32 Merging applicable 2.1 bugfixes`
22			`*`
23			`*/`
24
25			`/* todo:`
26			`* - see Documentation/filesystems/romfs.txt`
27			`* - use malloced memory for file names?`
28			`* - quicklist routines from fs/namei.c, get_page is possibly not`
29			`* intended to be used now`
30			`* - considering write access...`
31			`* - network (tftp) files?`
32			`* - in the ancient times something leaked to made umounts`
33			`* impossible, but I've not seen it in the last months`
34			`*/`
35
36			`/*`
37			`* Sorry about some optimizations and for some goto's. I just wanted`
38			`* to squeeze some more bytes out of this code.. :)`
39			`*/`
40
41			`#include <linux/module.h>`
42			`#include <linux/types.h>`
43			`#include <linux/errno.h>`
44			`#include <linux/malloc.h>`
45			`#include <linux/romfs_fs.h>`
46			`#include <linux/fs.h>`
47			`#include <linux/locks.h>`
48
49			`#include <asm/byteorder.h>`
50
51			`static int inline min(int a, int b)`
52			`{`
53			`return a<b ? a : b;`
54			`}`
55
56			`static __s32`
57			`romfs_checksum(void *data, int size)`
58			`{`
59			`__s32 sum, *ptr;`
60
61			`sum = 0; ptr = data;`
62			`size>>=2;`
63			`while (size>0) {`
64			`sum += ntohl(*ptr++);`
65			`size--;`
66			`}`
67			`return sum;`
68			`}`
69
70			`static struct super_operations romfs_ops;`
71
72			`static struct super_block *`
73			`romfs_read_super(struct super_block s, void data, int silent)`
74			`{`
75			`struct buffer_head *bh;`
76			`kdev_t dev = s->s_dev;`
77			`struct romfs_super_block *rsb;`
78			`int sz;`
79
80			`MOD_INC_USE_COUNT;`
81
82			`/* I would parse the options here, but there are none.. :) */`
83
84			`lock_super(s);`
85			`set_blocksize(dev, ROMBSIZE);`
86			`s->s_blocksize = ROMBSIZE;`
87			`s->s_blocksize_bits = ROMBSBITS;`
88			`bh = bread(dev, 0, ROMBSIZE);`
89			`if (!bh) {`
90			`/* XXX merge with other printk? */`
91			`printk ("romfs: unable to read superblock\n");`
92			`goto outnobh;`
93			`}`
94
95			`rsb = (struct romfs_super_block *)bh->b_data;`
96			`sz = ntohl(rsb->size);`
97			`if (rsb->word0 != ROMSB_WORD0 \|\| rsb->word1 != ROMSB_WORD1`
98			`\|\| sz < ROMFH_SIZE) {`
99			`if (!silent)`
100			`printk ("VFS: Can't find a romfs filesystem on dev "`
101			`"%s.\n", kdevname(dev));`
102			`goto out;`
103			`}`
104			`if (romfs_checksum(rsb, min(sz,512))) {`
105			`printk ("romfs: bad initial checksum on dev "`
106			`"%s.\n", kdevname(dev));`
107			`goto out;`
108			`}`
109
110			`s->s_magic = ROMFS_MAGIC;`
111			`s->u.romfs_sb.s_maxsize = sz;`
112
113			`s->s_flags \|= MS_RDONLY;`
114
115			`/* Find the start of the fs */`
116			`sz = (ROMFH_SIZE +`
117			`strnlen(rsb->name, ROMFS_MAXFN) + 1 + ROMFH_PAD)`
118			`& ROMFH_MASK;`
119
120			`brelse(bh);`
121
122			`s->s_op = &romfs_ops;`
123
124			`if (!(s->s_mounted = iget(s, sz)))`
125			`goto outnobh;`
126
127			`unlock_super(s);`
128
129			`/* Ehrhm; sorry.. :) And thanks to Hans-Joachim Widmaier :) */`
130			`if (0) {`
131			`out:`
132			`brelse(bh);`
133			`outnobh:`
134			`s->s_dev = 0;`
135			`unlock_super(s);`
136			`MOD_DEC_USE_COUNT;`
137			`s = NULL;`
138			`}`
139
140			`return s;`
141			`}`
142
143			`/* Nothing to do.. */`
144
145			`static void`
146			`romfs_put_super(struct super_block *sb)`
147			`{`
148			`lock_super(sb);`
149			`sb->s_dev = 0;`
150			`unlock_super(sb);`
151			`MOD_DEC_USE_COUNT;`
152			`return;`
153			`}`
154
155			`/* That's simple too. */`
156
157			`static void`
158			`romfs_statfs(struct super_block sb, struct statfs buf, int bufsize)`
159			`{`
160			`struct statfs tmp;`
161
162			`memset(&tmp, 0, sizeof(tmp));`
163			`tmp.f_type = ROMFS_MAGIC;`
164			`tmp.f_bsize = ROMBSIZE;`
165			`tmp.f_blocks = (sb->u.romfs_sb.s_maxsize+ROMBSIZE-1)>>ROMBSBITS;`
166			`memcpy_tofs(buf, &tmp, bufsize);`
167			`}`
168
169			`/* some helper routines */`
170
171			`static int`
172			`romfs_strnlen(struct inode *i, unsigned long offset, unsigned long count)`
173			`{`
174			`struct buffer_head *bh;`
175			`unsigned long avail, maxsize, res;`
176
177			`maxsize = i->i_sb->u.romfs_sb.s_maxsize;`
178			`if (offset >= maxsize)`
179			`return -1;`
180
181			`/* strnlen is almost always valid */`
182			`if (count > maxsize \|\| offset+count > maxsize)`
183			`count = maxsize-offset;`
184
185			`bh = bread(i->i_dev, offset>>ROMBSBITS, ROMBSIZE);`
186			`if (!bh)`
187			`return -1; /* error */`
188
189			`avail = ROMBSIZE - (offset & ROMBMASK);`
190			`maxsize = min(count, avail);`
191			`res = strnlen(((char *)bh->b_data)+(offset&ROMBMASK), maxsize);`
192			`brelse(bh);`
193
194			`if (res < maxsize)`
195			`return res; /* found all of it */`
196
197			`while (res < count) {`
198			`offset += maxsize;`
199
200			`bh = bread(i->i_dev, offset>>ROMBSBITS, ROMBSIZE);`
201			`if (!bh)`
202			`return -1;`
203			`maxsize = min(count-res, ROMBSIZE);`
204			`avail = strnlen(bh->b_data, maxsize);`
205			`res += avail;`
206			`brelse(bh);`
207			`if (avail < maxsize)`
208			`return res;`
209			`}`
210			`return res;`
211			`}`
212
213			`static int`
214			`romfs_copyfrom(struct inode i, void dest, unsigned long offset, unsigned long count)`
215			`{`
216			`struct buffer_head *bh;`
217			`unsigned long avail, maxsize, res;`
218
219			`maxsize = i->i_sb->u.romfs_sb.s_maxsize;`
220			`if (offset >= maxsize \|\| count > maxsize \|\| offset+count>maxsize)`
221			`return -1;`
222
223			`bh = bread(i->i_dev, offset>>ROMBSBITS, ROMBSIZE);`
224			`if (!bh)`
225			`return -1; /* error */`
226
227			`avail = ROMBSIZE - (offset & ROMBMASK);`
228			`maxsize = min(count, avail);`
229			`memcpy(dest, ((char *)bh->b_data) + (offset & ROMBMASK), maxsize);`
230			`brelse(bh);`
231
232			`res = maxsize; /* all of it */`
233
234			`while (res < count) {`
235			`offset += maxsize;`
236			`dest += maxsize;`
237
238			`bh = bread(i->i_dev, offset>>ROMBSBITS, ROMBSIZE);`
239			`if (!bh)`
240			`return -1;`
241			`maxsize = min(count-res, ROMBSIZE);`
242			`memcpy(dest, bh->b_data, maxsize);`
243			`brelse(bh);`
244			`res += maxsize;`
245			`}`
246			`return res;`
247			`}`
248
249			`/* Directory operations */`
250
251			`static int`
252			`romfs_readdir(struct inode i, struct file filp, void *dirent, filldir_t filldir)`
253			`{`
254			`struct romfs_inode ri;`
255			`unsigned long offset, maxoff;`
256			`int j, ino, nextfh;`
257			`int stored = 0;`
258			`char fsname[ROMFS_MAXFN]; /* XXX dynamic? */`
259
260			`if (!i \|\| !S_ISDIR(i->i_mode))`
261			`return -EBADF;`
262
263			`maxoff = i->i_sb->u.romfs_sb.s_maxsize;`
264
265			`offset = filp->f_pos;`
266			`if (!offset) {`
267			`offset = i->i_ino & ROMFH_MASK;`
268			`if (romfs_copyfrom(i, &ri, offset, ROMFH_SIZE) <= 0)`
269			`return stored;`
270			`offset = ntohl(ri.spec) & ROMFH_MASK;`
271			`}`
272
273			`/* Not really failsafe, but we are read-only... */`
274			`for(;;) {`
275			`if (!offset \|\| offset >= maxoff) {`
276			`offset = 0xffffffff;`
277			`filp->f_pos = offset;`
278			`return stored;`
279			`}`
280			`filp->f_pos = offset;`
281
282			`/* Fetch inode info */`
283			`if (romfs_copyfrom(i, &ri, offset, ROMFH_SIZE) <= 0)`
284			`return stored;`
285
286			`j = romfs_strnlen(i, offset+ROMFH_SIZE, sizeof(fsname)-1);`
287			`if (j < 0)`
288			`return stored;`
289
290			`fsname[j]=0;`
291			`romfs_copyfrom(i, fsname, offset+ROMFH_SIZE, j);`
292
293			`ino = offset;`
294			`nextfh = ntohl(ri.next);`
295			`if ((nextfh & ROMFH_TYPE) == ROMFH_HRD)`
296			`ino = ntohl(ri.spec);`
297			`if (filldir(dirent, fsname, j, offset, ino) < 0) {`
298			`return stored;`
299			`}`
300			`stored++;`
301			`offset = nextfh & ROMFH_MASK;`
302			`}`
303			`}`
304
305			`static int`
306			`romfs_lookup(struct inode dir, const char name, int len, struct inode **result)`
307			`{`
308			`unsigned long offset, maxoff;`
309			`int fslen, res;`
310			`char fsname[ROMFS_MAXFN]; /* XXX dynamic? */`
311			`struct romfs_inode ri;`
312
313			`*result = NULL;`
314			`if (!dir \|\| !S_ISDIR(dir->i_mode)) {`
315			`res = -EBADF;`
316			`goto out;`
317			`}`
318
319			`offset = dir->i_ino & ROMFH_MASK;`
320			`if (romfs_copyfrom(dir, &ri, offset, ROMFH_SIZE) <= 0) {`
321			`res = -ENOENT;`
322			`goto out;`
323			`}`
324
325			`maxoff = dir->i_sb->u.romfs_sb.s_maxsize;`
326			`offset = ntohl(ri.spec) & ROMFH_MASK;`
327
328			`for(;;) {`
329			`if (!offset \|\| offset >= maxoff`
330			`\|\| romfs_copyfrom(dir, &ri, offset, ROMFH_SIZE) <= 0) {`
331			`res = -ENOENT;`
332			`goto out;`
333			`}`
334
335			`/* try to match the first 16 bytes of name */`
336			`fslen = romfs_strnlen(dir, offset+ROMFH_SIZE, ROMFH_SIZE);`
337			`if (len < ROMFH_SIZE) {`
338			`if (len == fslen) {`
339			`/* both are shorter, and same size */`
340			`romfs_copyfrom(dir, fsname, offset+ROMFH_SIZE, len+1);`
341			`if (strncmp (name, fsname, len) == 0)`
342			`break;`
343			`}`
344			`} else if (fslen >= ROMFH_SIZE) {`
345			`/* both are longer; XXX optimize max size */`
346			`fslen = romfs_strnlen(dir, offset+ROMFH_SIZE, sizeof(fsname)-1);`
347			`if (len == fslen) {`
348			`romfs_copyfrom(dir, fsname, offset+ROMFH_SIZE, len+1);`
349			`if (strncmp(name, fsname, len) == 0)`
350			`break;`
351			`}`
352			`}`
353			`/* next entry */`
354			`offset = ntohl(ri.next) & ROMFH_MASK;`
355			`}`
356
357			`/* Hard link handling */`
358			`if ((ntohl(ri.next) & ROMFH_TYPE) == ROMFH_HRD)`
359			`offset = ntohl(ri.spec) & ROMFH_MASK;`
360
361			`res = 0;`
362			`if (!(*result = iget(dir->i_sb, offset)))`
363			`res = -EACCES;`
364
365			`out:`
366			`iput(dir);`
367			`return res;`
368			`}`
369
370			`/*`
371			`* Ok, we do readpage, to be able to execute programs. Unfortunately,`
372			`* we can't use bmap, since we have looser alignments.`
373			`*/`
374
375			`static int`
376			`romfs_readpage(struct inode * inode, struct page * page)`
377			`{`
378			`unsigned long buf;`
379			`unsigned long offset, avail, readlen;`
380			`int result = -EIO;`
381
382			`page->count++;`
383			`set_bit(PG_locked, &page->flags);`
384
385			`buf = page_address(page);`
386			`clear_bit(PG_uptodate, &page->flags);`
387			`clear_bit(PG_error, &page->flags);`
388			`offset = page->offset;`
389			`if (offset < inode->i_size) {`
390			`avail = inode->i_size-offset;`
391			`readlen = min(avail, PAGE_SIZE);`
392			`if (romfs_copyfrom(inode, (void *)buf, inode->u.romfs_i.i_dataoffset+offset, readlen) == readlen) {`
393			`if (readlen < PAGE_SIZE) {`
394			`memset((void *)(buf+readlen),0,PAGE_SIZE-readlen);`
395			`}`
396			`set_bit(PG_uptodate, &page->flags);`
397			`result = 0;`
398			`}`
399			`}`
400			`if (result) {`
401			`set_bit(PG_error, &page->flags);`
402			`memset((void *)buf, 0, PAGE_SIZE);`
403			`}`
404
405			`clear_bit(PG_locked, &page->flags);`
406			`wake_up(&page->wait);`
407			`free_page(buf);`
408
409			`return result;`
410			`}`
411
412			`#ifdef MAGIC_ROM_PTR`
413			`static int`
414			`romfs_romptr(struct inode * inode, struct file * filp, struct vm_area_struct * vma)`
415			`{`
416			`vma->vm_offset += inode->u.romfs_i.i_dataoffset;`
417
418			`if ((vma->vm_flags & VM_WRITE) \|\| bromptr(inode->i_dev, vma))`
419			`return -ENOSYS;`
420
421			`return 0;`
422			`}`
423			`#endif`
424
425			`static int`
426			`romfs_readlink(struct inode inode, char buffer, int len)`
427			`{`
428			`int mylen;`
429			`char buf[ROMFS_MAXFN]; /* XXX dynamic */`
430
431			`if (!inode \|\| !S_ISLNK(inode->i_mode)) {`
432			`mylen = -EBADF;`
433			`goto out;`
434			`}`
435
436			`mylen = min(sizeof(buf), inode->i_size);`
437
438			`if (romfs_copyfrom(inode, buf, inode->u.romfs_i.i_dataoffset, mylen) <= 0) {`
439			`mylen = -EIO;`
440			`goto out;`
441			`}`
442			`memcpy_tofs(buffer, buf, mylen);`
443
444			`out:`
445			`iput(inode);`
446			`return mylen;`
447			`}`
448
449			`static int`
450			`romfs_follow_link(struct inode dir, struct inode inode,`
451			`int flag, int mode, struct inode **res_inode)`
452			`{`
453			`int error, len;`
454			`char *buf;`
455
456			`*res_inode = NULL;`
457			`if (!dir) {`
458			`dir = current->fs->root;`
459			`dir->i_count++;`
460			`}`
461
462			`if (!inode) {`
463			`iput(dir);`
464			`return -ENOENT;`
465			`}`
466			`if (!S_ISLNK(inode->i_mode)) {`
467			`*res_inode = inode;`
468			`iput(dir);`
469			`return 0;`
470			`}`
471			`if (current->link_count > 5) {`
472			`iput(inode);`
473			`iput(dir);`
474			`return -ELOOP;`
475			`}`
476
477			`/* Eek. Short enough. */`
478			`len = inode->i_size;`
479			`if (!(buf = kmalloc(len+1, GFP_KERNEL))) {`
480			`iput(inode);`
481			`iput(dir);`
482			`/* correct? spin? */`
483			`return -EAGAIN;`
484			`}`
485			`error = romfs_copyfrom(inode, buf, inode->u.romfs_i.i_dataoffset, len);`
486			`if (error != len) {`
487			`iput(inode);`
488			`iput(dir);`
489			`error = -EIO;`
490			`} else {`
491			`iput(inode);`
492			`buf[len] = 0;`
493			`current->link_count++;`
494			`error = open_namei(buf, flag, mode, res_inode, dir);`
495			`current->link_count--;`
496			`}`
497
498			`kfree(buf);`
499			`return error;`
500			`}`
501
502			`/* Mapping from our types to the kernel */`
503
504			`static struct file_operations romfs_file_operations = {`
505			`NULL, /* lseek - default */`
506			`generic_file_read, /* read */`
507			`NULL, /* write - bad */`
508			`NULL, /* readdir */`
509			`NULL, /* select - default */`
510			`NULL, /* ioctl */`
511			`generic_file_mmap, /* mmap */`
512			`NULL, /* open */`
513			`NULL, /* release */`
514			`NULL, /* fsync */`
515			`NULL, /* fasync */`
516			`NULL, /* check_media_change */`
517			`NULL, /* revalidate */`
518			`#ifdef MAGIC_ROM_PTR`
519			`romfs_romptr, /* romptr */`
520			`#endif`
521			`};`
522
523			`static struct inode_operations romfs_file_inode_operations = {`
524			`&romfs_file_operations,`
525			`NULL, /* create */`
526			`NULL, /* lookup */`
527			`NULL, /* link */`
528			`NULL, /* unlink */`
529			`NULL, /* symlink */`
530			`NULL, /* mkdir */`
531			`NULL, /* rmdir */`
532			`NULL, /* mknod */`
533			`NULL, /* rename */`
534			`NULL, /* readlink */`
535			`NULL, /* follow_link */`
536			`romfs_readpage, /* readpage */`
537			`NULL, /* writepage */`
538			`NULL, /* bmap -- not really */`
539			`NULL, /* truncate */`
540			`NULL, /* permission */`
541			`NULL, /* smap */`
542			`};`
543
544			`static struct file_operations romfs_dir_operations = {`
545			`NULL, /* lseek - default */`
546			`NULL, /* read */`
547			`NULL, /* write - bad */`
548			`romfs_readdir, /* readdir */`
549			`NULL, /* select - default */`
550			`NULL, /* ioctl */`
551			`NULL, /* mmap */`
552			`NULL, /* open */`
553			`NULL, /* release */`
554			`NULL, /* fsync */`
555			`NULL, /* fasync */`
556			`NULL, /* check_media_change */`
557			`NULL /* revalidate */`
558			`};`
559
560			`/* Merged dir/symlink op table. readdir/lookup/readlink/follow_link`
561			`* will protect from type mismatch.`
562			`*/`
563
564			`static struct inode_operations romfs_dirlink_inode_operations = {`
565			`&romfs_dir_operations,`
566			`NULL, /* create */`
567			`romfs_lookup, /* lookup */`
568			`NULL, /* link */`
569			`NULL, /* unlink */`
570			`NULL, /* symlink */`
571			`NULL, /* mkdir */`
572			`NULL, /* rmdir */`
573			`NULL, /* mknod */`
574			`NULL, /* rename */`
575			`romfs_readlink, /* readlink */`
576			`romfs_follow_link, /* follow_link */`
577			`NULL, /* readpage */`
578			`NULL, /* writepage */`
579			`NULL, /* bmap */`
580			`NULL, /* truncate */`
581			`NULL, /* permission */`
582			`NULL, /* smap */`
583			`};`
584
585			`static mode_t romfs_modemap[] =`
586			`{`
587			`0, S_IFDIR, S_IFREG, S_IFLNK+0777,`
588			`S_IFBLK, S_IFCHR, S_IFSOCK, S_IFIFO`
589			`};`
590
591			`static struct inode_operations *romfs_inoops[] =`
592			`{`
593			`NULL, /* hardlink, handled elsewhere */`
594			`&romfs_dirlink_inode_operations,`
595			`&romfs_file_inode_operations,`
596			`&romfs_dirlink_inode_operations,`
597			`&blkdev_inode_operations, /* standard handlers */`
598			`&chrdev_inode_operations,`
599			`NULL, /* socket */`
600			`NULL, /* fifo */`
601			`};`
602
603			`static void`
604			`romfs_read_inode(struct inode *i)`
605			`{`
606			`int nextfh, ino;`
607			`struct romfs_inode ri;`
608
609			`ino = i->i_ino & ROMFH_MASK;`
610
611			`i->i_op = NULL;`
612			`i->i_mode = 0;`
613
614			`/* Loop for finding the real hard link */`
615			`for(;;) {`
616			`if (romfs_copyfrom(i, &ri, ino, ROMFH_SIZE) <= 0) {`
617			`printk("romfs: read error for inode 0x%x\n", ino);`
618			`return;`
619			`}`
620			`/* XXX: do romfs_checksum here too (with name) */`
621
622			`nextfh = ntohl(ri.next);`
623			`if ((nextfh & ROMFH_TYPE) != ROMFH_HRD)`
624			`break;`
625
626			`ino = ntohl(ri.spec) & ROMFH_MASK;`
627			`}`
628
629			`i->i_nlink = 1; /* Hard to decide.. */`
630			`i->i_size = ntohl(ri.size);`
631			`i->i_mtime = i->i_atime = i->i_ctime = 0;`
632			`i->i_uid = i->i_gid = 0;`
633
634			`i->i_op = romfs_inoops[nextfh & ROMFH_TYPE];`
635
636			`/* Precalculate the data offset */`
637			`ino = romfs_strnlen(i, ino+ROMFH_SIZE, ROMFS_MAXFN);`
638			`if (ino >= 0)`
639			`ino = ((ROMFH_SIZE+ino+1+ROMFH_PAD)&ROMFH_MASK);`
640			`else`
641			`ino = 0;`
642
643			`i->u.romfs_i.i_metasize = ino;`
644			`i->u.romfs_i.i_dataoffset = ino+(i->i_ino&ROMFH_MASK);`
645
646			`/* Compute permissions */`
647			`ino = S_IRUGO\|S_IWUSR;`
648			`ino \|= romfs_modemap[nextfh & ROMFH_TYPE];`
649			`if (nextfh & ROMFH_EXEC) {`
650			`ino \|= S_IXUGO;`
651			`}`
652			`i->i_mode = ino;`
653
654			`if (S_ISFIFO(ino))`
655			`init_fifo(i);`
656			`else if (S_ISDIR(ino))`
657			`i->i_size = i->u.romfs_i.i_metasize;`
658			`else if (S_ISBLK(ino) \|\| S_ISCHR(ino)) {`
659			`i->i_mode &= ~(S_IRWXG\|S_IRWXO);`
660			`ino = ntohl(ri.spec);`
661			`i->i_rdev = MKDEV(ino>>16,ino&0xffff);`
662			`}`
663			`}`
664
665			`static struct super_operations romfs_ops = {`
666			`romfs_read_inode, /* read inode */`
667			`NULL, /* notify change */`
668			`NULL, /* write inode */`
669			`NULL, /* put inode */`
670			`romfs_put_super, /* put super */`
671			`NULL, /* write super */`
672			`romfs_statfs, /* statfs */`
673			`NULL /* remount */`
674			`};`
675
676			`static struct file_system_type romfs_fs_type = {`
677			`romfs_read_super, "romfs", 1, NULL`
678			`};`
679
680			`int`
681			`init_romfs_fs(void)`
682			`{`
683			`return register_filesystem(&romfs_fs_type);`
684			`}`
685
686			`#ifdef MODULE`
687
688			`/* Yes, works even as a module... :) */`
689
690			`int`
691			`init_module(void)`
692			`{`
693			`int status;`
694
695			`if ((status = init_romfs_fs()) == 0)`
696			`register_symtab(0);`
697			`return status;`
698			`}`
699
700			`void`
701			`cleanup_module(void)`
702			`{`
703			`unregister_filesystem(&romfs_fs_type);`
704			`}`
705			`#endif`