Creation of Cybook 2416 (actually Gen4) repository

fs/romfs/Makefile

@@ -0,0 +1,7 @@
+#
+# Makefile for the linux romfs filesystem routines.
+#
+
+obj-$(CONFIG_ROMFS_FS) += romfs.o
+
+romfs-objs := inode.o

fs/romfs/inode.c

@@ -0,0 +1,649 @@
+/*
+ * 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;
+};
+
+/* 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 list_entry(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;
+
+	/* 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 = iget(s, sz);
+	if (!root)
+		goto out;
+
+	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 -EINVAL;
+}
+
+/* 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;
+	int fslen, res;
+	struct inode *inode;
+	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 out;
+
+	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 out0;
+		if (romfs_copyfrom(dir, &ri, offset, ROMFH_SIZE) <= 0)
+			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 = 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;
+
+	if ((inode = iget(dir->i_sb, offset)))
+		goto outi;
+
+	/*
+	 * it's a bit funky, _lookup needs to return an error code
+	 * (negative) or a NULL, both as a dentry.  ENOENT should not
+	 * be returned, instead we need to create a negative dentry by
+	 * d_add(dentry, NULL); and return 0 as no error.
+	 * (Although as I see, it only matters on writable file
+	 * systems).
+	 */
+
+out0:	inode = NULL;
+outi:	res = 0;
+	d_add (dentry, inode);
+
+out:	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, avail, readlen;
+	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);
+	if (offset < i_size_read(inode)) {
+		avail = inode->i_size-offset;
+		readlen = min_t(unsigned long, avail, PAGE_SIZE);
+		if (romfs_copyfrom(inode, buf, ROMFS_I(inode)->i_dataoffset+offset, readlen) == readlen) {
+			if (readlen < PAGE_SIZE) {
+				memset(buf + readlen,0,PAGE_SIZE-readlen);
+			}
+			SetPageUptodate(page);
+			result = 0;
+		}
+	}
+	if (result) {
+		memset(buf, 0, PAGE_SIZE);
+		SetPageError(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 void
+romfs_read_inode(struct inode *i)
+{
+	int nextfh, ino;
+	struct romfs_inode ri;
+
+	ino = i->i_ino & ROMFH_MASK;
+	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 = 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;
+	i->i_uid = i->i_gid = 0;
+
+        /* 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;
+
+        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));
+	}
+}
+
+static struct kmem_cache * romfs_inode_cachep;
+
+static struct inode *romfs_alloc_inode(struct super_block *sb)
+{
+	struct romfs_inode_info *ei;
+	ei = (struct romfs_inode_info *)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 kmem_cache * cachep, unsigned long flags)
+{
+	struct romfs_inode_info *ei = (struct romfs_inode_info *) foo;
+
+	if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
+	    SLAB_CTOR_CONSTRUCTOR)
+		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, NULL);
+	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,
+	.read_inode	= romfs_read_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");