www.pudn.com > cryptfs030905.rar > main.c
/*
* Copyright (c) 1997-2003 Erez Zadok
* Copyright (c) 2001-2003 Stony Brook University
*
* For specific licensing information, see the COPYING file distributed with
* this package, or get one from ftp://ftp.filesystems.org/pub/fist/COPYING.
*
* This Copyright notice must be kept intact and distributed with all
* fistgen sources INCLUDING sources generated by fistgen.
*/
/*
* $Id: main.c,v 1.36 2003/07/29 18:17:20 ezk Exp $
*/
#ifdef HAVE_CONFIG_H
# include
#endif /* HAVE_CONFIG_H */
#ifdef FISTGEN
# include "fist_cryptfs.h"
#endif /* FISTGEN */
#include "fist.h"
#include "cryptfs.h"
#include
/* This definition must only appear after we include */
#ifndef MODULE_LICENSE
# define MODULE_LICENSE(bison)
#endif /* not MODULE_LICENSE */
/* sb we pass is cryptfs's super_block */
int
cryptfs_interpose(dentry_t *hidden_dentry, dentry_t *dentry, super_block_t *sb, int flag)
{
inode_t *hidden_inode;
int err = 0;
inode_t *inode;
print_entry_location();
hidden_inode = hidden_dentry->d_inode; /* CPW: moved after print_entry_location */
ASSERT(hidden_inode != NULL);
ASSERT(dentry->d_inode == NULL);
/*
* We allocate our new inode below, by calling iget.
* iget will call our read_inode which will initialize some
* of the new inode's fields
*/
/* XXX: fist file systems reserve first 10 inodes */
inode = iget(sb, cryptfs_iunique(sb, 10));
if (!inode) {
err = -EACCES; /* should be impossible??? */
goto out;
}
/*
* interpose the inode if not already interposed
* this is possible if the inode is being reused
* XXX: what happens if we get_empty_inode() but there's another already?
* for now, ASSERT() that this can't happen; fix later.
*/
if (itohi(inode) == NULL)
itohi(inode) = igrab(hidden_inode);
/* Use different set of inode ops for symlinks & directories*/
if (S_ISLNK(hidden_inode->i_mode))
inode->i_op = &cryptfs_symlink_iops;
else if (S_ISDIR(hidden_inode->i_mode))
inode->i_op = &cryptfs_dir_iops;
/* Use different set of file ops for directories */
if (S_ISDIR(hidden_inode->i_mode))
inode->i_fop = &cryptfs_dir_fops;
/* properly initialize special inodes */
if (S_ISBLK(hidden_inode->i_mode) || S_ISCHR(hidden_inode->i_mode) ||
S_ISFIFO(hidden_inode->i_mode) || S_ISSOCK(hidden_inode->i_mode)) {
init_special_inode(inode, hidden_inode->i_mode, hidden_inode->i_rdev);
}
/* only (our) lookup wants to do a d_add */
if (flag)
d_add(dentry, inode);
else
d_instantiate(dentry, inode);
ASSERT(dtopd(dentry) != NULL);
/* all well, copy inode attributes */
fist_copy_attr_all(inode, hidden_inode);
out:
print_exit_status(err);
return err;
}
/* find hidden dentry given this cryptfs dentry */
dentry_t *
__cryptfs_hidden_dentry(char *file, char *func, int line, dentry_t *dentry)
{
dentry_t *hidden_dentry;
ASSERT2(dentry != NULL);
ASSERT2(dentry->d_op != NULL);
ASSERT2(dentry->d_op == &cryptfs_dops
// XXX: we may need a special version of this fxn for attach mode
|| dentry->d_op == &cryptfs_attach_dops
);
ASSERT2(dentry->d_sb->s_op == &cryptfs_sops);
if (dentry->d_inode)
ASSERT2(dentry->d_inode->i_op == &cryptfs_main_iops ||
dentry->d_inode->i_op == &cryptfs_dir_iops ||
// XXX: we may need a special version of this fxn for attach mode
dentry->d_inode->i_op == &cryptfs_dir_attach_iops ||
dentry->d_inode->i_op == &cryptfs_symlink_iops);
hidden_dentry = dtohd(dentry);
ASSERT2(hidden_dentry != NULL);
return hidden_dentry;
}
/*
* Parse mount options: dir=XXX and debug=N
*
* Returns the dentry object of the lower-level (hidden) directory;
* We want to mount our stackable file system on top of that hidden directory.
*
* Sets default debugging level to N, if any.
*/
dentry_t *
cryptfs_parse_options(super_block_t *sb, char *options)
{
dentry_t *hidden_root = ERR_PTR(-EINVAL);
struct nameidata nd;
char *name, *tmp, *end;
int err = 0;
print_entry_location();
/* We don't want to go off the end of our arguments later on. */
for (end = options; *end; end++);
while (options < end) {
tmp = options;
while (*tmp && *tmp != ',')
tmp++;
*tmp = '\0';
if (!strncmp("dir=", options, 4)) {
/* note: the name passed need not be encoded */
name = options + 4;
fist_dprint(4, "cryptfs: using directory: %s\n", name);
if (path_init(name, LOOKUP_FOLLOW, &nd))
err = path_walk(name, &nd);
if (err) {
printk("cryptfs: error accessing hidden directory '%s'\n", name);
hidden_root = ERR_PTR(err);
goto out;
}
hidden_root = nd.dentry;
stopd(sb)->hidden_mnt = nd.mnt;
fist_dprint(6, "parse_options: new s_root, inode: 0x%lx, 0x%lx\n",
(long) hidden_root, (long) hidden_root->d_inode);
} else if (!strncmp("debug=", options, 6)) {
int debug = simple_strtoul(options + 6, NULL, 0);
fist_set_debug_value(debug);
} else {
printk(KERN_WARNING "cryptfs: unrecognized option '%s'\n", options);
}
options = tmp + 1;
}
out:
print_exit_location();
return hidden_root;
}
/* wrapper to iunique to warn if we have a wrap-around */
ino_t
cryptfs_iunique(struct super_block *sb, ino_t maxreserved)
{
static ino_t counter = 0;
ino_t ret;
ret = iunique(sb, maxreserved);
if (ret < counter) {
printk(KERN_WARNING "%s iunique may have wrapped around!\n", __FUNCTION__);
}
counter = ret;
return ret;
}
/*----*/
// this structure *must* be static!!! (or the memory for 'name' gets
// corrupted in 2.3...)
static DECLARE_FSTYPE(cryptfs_fs_type, "cryptfs", cryptfs_read_super, 0);
static int __init init_cryptfs_fs(void)
{
printk("Registering cryptfs version $Id: main.c,v 1.36 2003/07/29 18:17:20 ezk Exp $\n");
return register_filesystem(&cryptfs_fs_type);
}
static void __exit exit_cryptfs_fs(void)
{
printk("Unregistering cryptfs version $Id: main.c,v 1.36 2003/07/29 18:17:20 ezk Exp $\n");
unregister_filesystem(&cryptfs_fs_type);
}
EXPORT_NO_SYMBOLS;
MODULE_AUTHOR("Erez Zadok ");
MODULE_DESCRIPTION("FiST-generated cryptfs filesystem");
MODULE_LICENSE("LGPL");
MODULE_PARM(fist_debug_var, "i");
MODULE_PARM_DESC(fist_debug_var, "Debug level");
module_init(init_cryptfs_fs)
module_exit(exit_cryptfs_fs)
/*
* Local variables:
* c-basic-offset: 4
* End:
*/