+++ /dev/null
-/*
- * ROMFS file system, Linux implementation
- *
- * Copyright (C) 1997-1999 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
- * Jun 1997 2.1.43+ changes
- * Proper page locking in readpage
- * Changed to work with 2.1.45+ fs
- * Jul 1997 Fixed follow_link
- * 2.1.47
- * lookup shouldn't return -ENOENT
- * from Horst von Brand:
- * fail on wrong checksum
- * double unlock_super was possible
- * correct namelen for statfs
- * spotted by Bill Hawes:
- * readlink shouldn't iput()
- * Jun 1998 2.1.106 from Avery Pennarun: glibc scandir()
- * exposed a problem in readdir
- * 2.1.107 code-freeze spellchecker run
- * Aug 1998 2.1.118+ VFS changes
- * Sep 1998 2.1.122 another VFS change (follow_link)
- * Apr 1999 2.2.7 no more EBADF checking in
- * lookup/readdir, use ERR_PTR
- * Jun 1999 2.3.6 d_alloc_root use changed
- * 2.3.9 clean up usage of ENOENT/negative
- * dentries in lookup
- * clean up page flags setting
- * (error, uptodate, locking) in
- * in readpage
- * use init_special_inode for
- * fifos/sockets (and streamline) in
- * read_inode, fix _ops table order
- * Aug 1999 2.3.16 __initfunc() => __init change
- * Oct 1999 2.3.24 page->owner hack obsoleted
- * Nov 1999 2.3.27 2.3.25+ page->offset => index change
- */
-
-/* todo:
- * - see Documentation/filesystems/romfs.txt
- * - use allocated, not stack memory for file names?
- * - considering write access...
- * - network (tftp) files?
- * - merge back some _op tables
- */
-
-/*
- * 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/slab.h>
-#include <linux/romfs_fs.h>
-#include <linux/fs.h>
-#include <linux/init.h>
-#include <linux/pagemap.h>
-#include <linux/smp_lock.h>
-#include <linux/buffer_head.h>
-#include <linux/vfs.h>
-
-#include <asm/uaccess.h>
-
-struct romfs_inode_info {
- unsigned long i_metasize; /* size of non-data area */
- unsigned long i_dataoffset; /* from the start of fs */
- struct inode vfs_inode;
-};
-
-static struct inode *romfs_iget(struct super_block *, unsigned long);
-
-/* instead of private superblock data */
-static inline unsigned long romfs_maxsize(struct super_block *sb)
-{
- return (unsigned long)sb->s_fs_info;
-}
-
-static inline struct romfs_inode_info *ROMFS_I(struct inode *inode)
-{
- return container_of(inode, struct romfs_inode_info, vfs_inode);
-}
-
-static __u32
-romfs_checksum(void *data, int size)
-{
- __u32 sum;
- __be32 *ptr;
-
- sum = 0; ptr = data;
- size>>=2;
- while (size>0) {
- sum += be32_to_cpu(*ptr++);
- size--;
- }
- return sum;
-}
-
-static const struct super_operations romfs_ops;
-
-static int romfs_fill_super(struct super_block *s, void *data, int silent)
-{
- struct buffer_head *bh;
- struct romfs_super_block *rsb;
- struct inode *root;
- int sz, ret = -EINVAL;
-
- /* I would parse the options here, but there are none.. :) */
-
- sb_set_blocksize(s, ROMBSIZE);
- s->s_maxbytes = 0xFFFFFFFF;
-
- bh = sb_bread(s, 0);
- 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 = be32_to_cpu(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", s->s_id);
- goto out;
- }
- if (romfs_checksum(rsb, min_t(int, sz, 512))) {
- printk ("romfs: bad initial checksum on dev "
- "%s.\n", s->s_id);
- goto out;
- }
-
- s->s_magic = ROMFS_MAGIC;
- s->s_fs_info = (void *)(long)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;
-
- s->s_op = &romfs_ops;
- root = romfs_iget(s, sz);
- if (IS_ERR(root)) {
- ret = PTR_ERR(root);
- goto out;
- }
-
- ret = -ENOMEM;
- s->s_root = d_alloc_root(root);
- if (!s->s_root)
- goto outiput;
-
- brelse(bh);
- return 0;
-
-outiput:
- iput(root);
-out:
- brelse(bh);
-outnobh:
- return ret;
-}
-
-/* That's simple too. */
-
-static int
-romfs_statfs(struct dentry *dentry, struct kstatfs *buf)
-{
- buf->f_type = ROMFS_MAGIC;
- buf->f_bsize = ROMBSIZE;
- buf->f_bfree = buf->f_bavail = buf->f_ffree;
- buf->f_blocks = (romfs_maxsize(dentry->d_sb)+ROMBSIZE-1)>>ROMBSBITS;
- buf->f_namelen = ROMFS_MAXFN;
- return 0;
-}
-
-/* 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 = romfs_maxsize(i->i_sb);
- if (offset >= maxsize)
- return -1;
-
- /* strnlen is almost always valid */
- if (count > maxsize || offset+count > maxsize)
- count = maxsize-offset;
-
- bh = sb_bread(i->i_sb, offset>>ROMBSBITS);
- if (!bh)
- return -1; /* error */
-
- avail = ROMBSIZE - (offset & ROMBMASK);
- maxsize = min_t(unsigned long, 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 = sb_bread(i->i_sb, offset>>ROMBSBITS);
- if (!bh)
- return -1;
- maxsize = min_t(unsigned long, 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 = romfs_maxsize(i->i_sb);
- if (offset >= maxsize || count > maxsize || offset+count>maxsize)
- return -1;
-
- bh = sb_bread(i->i_sb, offset>>ROMBSBITS);
- if (!bh)
- return -1; /* error */
-
- avail = ROMBSIZE - (offset & ROMBMASK);
- maxsize = min_t(unsigned long, 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 = sb_bread(i->i_sb, offset>>ROMBSBITS);
- if (!bh)
- return -1;
- maxsize = min_t(unsigned long, count - res, ROMBSIZE);
- memcpy(dest, bh->b_data, maxsize);
- brelse(bh);
- res += maxsize;
- }
- return res;
-}
-
-static unsigned char romfs_dtype_table[] = {
- DT_UNKNOWN, DT_DIR, DT_REG, DT_LNK, DT_BLK, DT_CHR, DT_SOCK, DT_FIFO
-};
-
-static int
-romfs_readdir(struct file *filp, void *dirent, filldir_t filldir)
-{
- struct inode *i = filp->f_path.dentry->d_inode;
- struct romfs_inode ri;
- unsigned long offset, maxoff;
- int j, ino, nextfh;
- int stored = 0;
- char fsname[ROMFS_MAXFN]; /* XXX dynamic? */
-
- lock_kernel();
-
- maxoff = romfs_maxsize(i->i_sb);
-
- offset = filp->f_pos;
- if (!offset) {
- offset = i->i_ino & ROMFH_MASK;
- if (romfs_copyfrom(i, &ri, offset, ROMFH_SIZE) <= 0)
- goto out;
- offset = be32_to_cpu(ri.spec) & ROMFH_MASK;
- }
-
- /* Not really failsafe, but we are read-only... */
- for(;;) {
- if (!offset || offset >= maxoff) {
- offset = maxoff;
- filp->f_pos = offset;
- goto out;
- }
- filp->f_pos = offset;
-
- /* Fetch inode info */
- if (romfs_copyfrom(i, &ri, offset, ROMFH_SIZE) <= 0)
- goto out;
-
- j = romfs_strnlen(i, offset+ROMFH_SIZE, sizeof(fsname)-1);
- if (j < 0)
- goto out;
-
- fsname[j]=0;
- romfs_copyfrom(i, fsname, offset+ROMFH_SIZE, j);
-
- ino = offset;
- nextfh = be32_to_cpu(ri.next);
- if ((nextfh & ROMFH_TYPE) == ROMFH_HRD)
- ino = be32_to_cpu(ri.spec);
- if (filldir(dirent, fsname, j, offset, ino,
- romfs_dtype_table[nextfh & ROMFH_TYPE]) < 0) {
- goto out;
- }
- stored++;
- offset = nextfh & ROMFH_MASK;
- }
-out:
- unlock_kernel();
- return stored;
-}
-
-static struct dentry *
-romfs_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
-{
- unsigned long offset, maxoff;
- long res;
- int fslen;
- struct inode *inode = NULL;
- char fsname[ROMFS_MAXFN]; /* XXX dynamic? */
- struct romfs_inode ri;
- const char *name; /* got from dentry */
- int len;
-
- res = -EACCES; /* placeholder for "no data here" */
- offset = dir->i_ino & ROMFH_MASK;
- lock_kernel();
- if (romfs_copyfrom(dir, &ri, offset, ROMFH_SIZE) <= 0)
- goto error;
-
- maxoff = romfs_maxsize(dir->i_sb);
- offset = be32_to_cpu(ri.spec) & ROMFH_MASK;
-
- /* OK, now find the file whose name is in "dentry" in the
- * directory specified by "dir". */
-
- name = dentry->d_name.name;
- len = dentry->d_name.len;
-
- for(;;) {
- if (!offset || offset >= maxoff)
- goto success; /* negative success */
- if (romfs_copyfrom(dir, &ri, offset, ROMFH_SIZE) <= 0)
- goto error;
-
- /* 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 = be32_to_cpu(ri.next) & ROMFH_MASK;
- }
-
- /* Hard link handling */
- if ((be32_to_cpu(ri.next) & ROMFH_TYPE) == ROMFH_HRD)
- offset = be32_to_cpu(ri.spec) & ROMFH_MASK;
-
- inode = romfs_iget(dir->i_sb, offset);
- if (IS_ERR(inode)) {
- res = PTR_ERR(inode);
- goto error;
- }
-
-success:
- d_add(dentry, inode);
- res = 0;
-error:
- unlock_kernel();
- return ERR_PTR(res);
-}
-
-/*
- * Ok, we do readpage, to be able to execute programs. Unfortunately,
- * we can't use bmap, since we may have looser alignments.
- */
-
-static int
-romfs_readpage(struct file *file, struct page * page)
-{
- struct inode *inode = page->mapping->host;
- loff_t offset, size;
- unsigned long filled;
- void *buf;
- int result = -EIO;
-
- page_cache_get(page);
- lock_kernel();
- buf = kmap(page);
- if (!buf)
- goto err_out;
-
- /* 32 bit warning -- but not for us :) */
- offset = page_offset(page);
- size = i_size_read(inode);
- filled = 0;
- result = 0;
- if (offset < size) {
- unsigned long readlen;
-
- size -= offset;
- readlen = size > PAGE_SIZE ? PAGE_SIZE : size;
-
- filled = romfs_copyfrom(inode, buf, ROMFS_I(inode)->i_dataoffset+offset, readlen);
-
- if (filled != readlen) {
- SetPageError(page);
- filled = 0;
- result = -EIO;
- }
- }
-
- if (filled < PAGE_SIZE)
- memset(buf + filled, 0, PAGE_SIZE-filled);
-
- if (!result)
- SetPageUptodate(page);
- flush_dcache_page(page);
-
- unlock_page(page);
-
- kunmap(page);
-err_out:
- page_cache_release(page);
- unlock_kernel();
-
- return result;
-}
-
-/* Mapping from our types to the kernel */
-
-static const struct address_space_operations romfs_aops = {
- .readpage = romfs_readpage
-};
-
-static const struct file_operations romfs_dir_operations = {
- .read = generic_read_dir,
- .readdir = romfs_readdir,
-};
-
-static const struct inode_operations romfs_dir_inode_operations = {
- .lookup = romfs_lookup,
-};
-
-static mode_t romfs_modemap[] =
-{
- 0, S_IFDIR+0644, S_IFREG+0644, S_IFLNK+0777,
- S_IFBLK+0600, S_IFCHR+0600, S_IFSOCK+0644, S_IFIFO+0644
-};
-
-static struct inode *
-romfs_iget(struct super_block *sb, unsigned long ino)
-{
- int nextfh, ret;
- struct romfs_inode ri;
- struct inode *i;
-
- ino &= ROMFH_MASK;
- i = iget_locked(sb, ino);
- if (!i)
- return ERR_PTR(-ENOMEM);
- if (!(i->i_state & I_NEW))
- return i;
-
- i->i_mode = 0;
-
- /* Loop for finding the real hard link */
- for(;;) {
- if (romfs_copyfrom(i, &ri, ino, ROMFH_SIZE) <= 0) {
- printk(KERN_ERR "romfs: read error for inode 0x%lx\n",
- ino);
- iget_failed(i);
- return ERR_PTR(-EIO);
- }
- /* XXX: do romfs_checksum here too (with name) */
-
- nextfh = be32_to_cpu(ri.next);
- if ((nextfh & ROMFH_TYPE) != ROMFH_HRD)
- break;
-
- ino = be32_to_cpu(ri.spec) & ROMFH_MASK;
- }
-
- i->i_nlink = 1; /* Hard to decide.. */
- i->i_size = be32_to_cpu(ri.size);
- i->i_mtime.tv_sec = i->i_atime.tv_sec = i->i_ctime.tv_sec = 0;
- i->i_mtime.tv_nsec = i->i_atime.tv_nsec = i->i_ctime.tv_nsec = 0;
-
- /* Precalculate the data offset */
- ret = romfs_strnlen(i, ino + ROMFH_SIZE, ROMFS_MAXFN);
- if (ret >= 0)
- ino = (ROMFH_SIZE + ret + 1 + ROMFH_PAD) & ROMFH_MASK;
- else
- ino = 0;
-
- ROMFS_I(i)->i_metasize = ino;
- ROMFS_I(i)->i_dataoffset = ino+(i->i_ino&ROMFH_MASK);
-
- /* Compute permissions */
- ino = romfs_modemap[nextfh & ROMFH_TYPE];
- /* only "normal" files have ops */
- switch (nextfh & ROMFH_TYPE) {
- case 1:
- i->i_size = ROMFS_I(i)->i_metasize;
- i->i_op = &romfs_dir_inode_operations;
- i->i_fop = &romfs_dir_operations;
- if (nextfh & ROMFH_EXEC)
- ino |= S_IXUGO;
- i->i_mode = ino;
- break;
- case 2:
- i->i_fop = &generic_ro_fops;
- i->i_data.a_ops = &romfs_aops;
- if (nextfh & ROMFH_EXEC)
- ino |= S_IXUGO;
- i->i_mode = ino;
- break;
- case 3:
- i->i_op = &page_symlink_inode_operations;
- i->i_data.a_ops = &romfs_aops;
- i->i_mode = ino | S_IRWXUGO;
- break;
- default:
- /* depending on MBZ for sock/fifos */
- nextfh = be32_to_cpu(ri.spec);
- init_special_inode(i, ino,
- MKDEV(nextfh>>16,nextfh&0xffff));
- }
- unlock_new_inode(i);
- return i;
-}
-
-static struct kmem_cache * romfs_inode_cachep;
-
-static struct inode *romfs_alloc_inode(struct super_block *sb)
-{
- struct romfs_inode_info *ei;
- ei = kmem_cache_alloc(romfs_inode_cachep, GFP_KERNEL);
- if (!ei)
- return NULL;
- return &ei->vfs_inode;
-}
-
-static void romfs_destroy_inode(struct inode *inode)
-{
- kmem_cache_free(romfs_inode_cachep, ROMFS_I(inode));
-}
-
-static void init_once(void *foo)
-{
- struct romfs_inode_info *ei = foo;
-
- inode_init_once(&ei->vfs_inode);
-}
-
-static int init_inodecache(void)
-{
- romfs_inode_cachep = kmem_cache_create("romfs_inode_cache",
- sizeof(struct romfs_inode_info),
- 0, (SLAB_RECLAIM_ACCOUNT|
- SLAB_MEM_SPREAD),
- init_once);
- if (romfs_inode_cachep == NULL)
- return -ENOMEM;
- return 0;
-}
-
-static void destroy_inodecache(void)
-{
- kmem_cache_destroy(romfs_inode_cachep);
-}
-
-static int romfs_remount(struct super_block *sb, int *flags, char *data)
-{
- *flags |= MS_RDONLY;
- return 0;
-}
-
-static const struct super_operations romfs_ops = {
- .alloc_inode = romfs_alloc_inode,
- .destroy_inode = romfs_destroy_inode,
- .statfs = romfs_statfs,
- .remount_fs = romfs_remount,
-};
-
-static int romfs_get_sb(struct file_system_type *fs_type,
- int flags, const char *dev_name, void *data, struct vfsmount *mnt)
-{
- return get_sb_bdev(fs_type, flags, dev_name, data, romfs_fill_super,
- mnt);
-}
-
-static struct file_system_type romfs_fs_type = {
- .owner = THIS_MODULE,
- .name = "romfs",
- .get_sb = romfs_get_sb,
- .kill_sb = kill_block_super,
- .fs_flags = FS_REQUIRES_DEV,
-};
-
-static int __init init_romfs_fs(void)
-{
- int err = init_inodecache();
- if (err)
- goto out1;
- err = register_filesystem(&romfs_fs_type);
- if (err)
- goto out;
- return 0;
-out:
- destroy_inodecache();
-out1:
- return err;
-}
-
-static void __exit exit_romfs_fs(void)
-{
- unregister_filesystem(&romfs_fs_type);
- destroy_inodecache();
-}
-
-/* Yes, works even as a module... :) */
-
-module_init(init_romfs_fs)
-module_exit(exit_romfs_fs)
-MODULE_LICENSE("GPL");
git.samba.org / sfrench / cifs-2.6.git / blobdiff