export.c

来自「Linux Kernel 2.6.9 for OMAP1710」· C语言 代码 · 共 1,206 行 · 第 1/2 页

#define MSNFS	/* HACK HACK */
/*
 * linux/fs/nfsd/export.c
 *
 * NFS exporting and validation.
 *
 * We maintain a list of clients, each of which has a list of
 * exports. To export an fs to a given client, you first have
 * to create the client entry with NFSCTL_ADDCLIENT, which
 * creates a client control block and adds it to the hash
 * table. Then, you call NFSCTL_EXPORT for each fs.
 *
 *
 * Copyright (C) 1995, 1996 Olaf Kirch, <[e-mail]>
 */

#include <linux/unistd.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/stat.h>
#include <linux/in.h>
#include <linux/seq_file.h>
#include <linux/syscalls.h>
#include <linux/rwsem.h>
#include <linux/dcache.h>
#include <linux/namei.h>
#include <linux/mount.h>
#include <linux/hash.h>

#include <linux/sunrpc/svc.h>
#include <linux/nfsd/nfsd.h>
#include <linux/nfsd/nfsfh.h>
#include <linux/nfsd/syscall.h>
#include <linux/lockd/bind.h>

#define NFSDDBG_FACILITY	NFSDDBG_EXPORT
#define NFSD_PARANOIA 1

typedef struct auth_domain	svc_client;
typedef struct svc_export	svc_export;

static void		exp_do_unexport(svc_export *unexp);
static int		exp_verify_string(char *cp, int max);

/*
 * We have two caches.
 * One maps client+vfsmnt+dentry to export options - the export map
 * The other maps client+filehandle-fragment to export options. - the expkey map
 *
 * The export options are actually stored in the first map, and the
 * second map contains a reference to the entry in the first map.
 */

#define	EXPKEY_HASHBITS		8
#define	EXPKEY_HASHMAX		(1 << EXPKEY_HASHBITS)
#define	EXPKEY_HASHMASK		(EXPKEY_HASHMAX -1)
static struct cache_head *expkey_table[EXPKEY_HASHMAX];

static inline int svc_expkey_hash(struct svc_expkey *item)
{
	int hash = item->ek_fsidtype;
	char * cp = (char*)item->ek_fsid;
	int len = key_len(item->ek_fsidtype);

	hash ^= hash_mem(cp, len, EXPKEY_HASHBITS);
	hash ^= hash_ptr(item->ek_client, EXPKEY_HASHBITS);
	return hash & EXPKEY_HASHMASK;
}

void expkey_put(struct cache_head *item, struct cache_detail *cd)
{
	if (cache_put(item, cd)) {
		struct svc_expkey *key = container_of(item, struct svc_expkey, h);
		if (test_bit(CACHE_VALID, &item->flags) &&
		    !test_bit(CACHE_NEGATIVE, &item->flags))
			exp_put(key->ek_export);
		auth_domain_put(key->ek_client);
		kfree(key);
	}
}

void expkey_request(struct cache_detail *cd,
		    struct cache_head *h,
		    char **bpp, int *blen)
{
	/* client fsidtype \xfsid */
	struct svc_expkey *ek = container_of(h, struct svc_expkey, h);
	char type[5];

	qword_add(bpp, blen, ek->ek_client->name);
	snprintf(type, 5, "%d", ek->ek_fsidtype);
	qword_add(bpp, blen, type);
	qword_addhex(bpp, blen, (char*)ek->ek_fsid, key_len(ek->ek_fsidtype));
	(*bpp)[-1] = '\n';
}

static struct svc_expkey *svc_expkey_lookup(struct svc_expkey *, int);
int expkey_parse(struct cache_detail *cd, char *mesg, int mlen)
{
	/* client fsidtype fsid [path] */
	char *buf;
	int len;
	struct auth_domain *dom = NULL;
	int err;
	int fsidtype;
	char *ep;
	struct svc_expkey key;

	if (mesg[mlen-1] != '\n')
		return -EINVAL;
	mesg[mlen-1] = 0;

	buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
	err = -ENOMEM;
	if (!buf) goto out;

	err = -EINVAL;
	if ((len=qword_get(&mesg, buf, PAGE_SIZE)) <= 0)
		goto out;

	err = -ENOENT;
	dom = auth_domain_find(buf);
	if (!dom)
		goto out;
	dprintk("found domain %s\n", buf);

	err = -EINVAL;
	if ((len=qword_get(&mesg, buf, PAGE_SIZE)) <= 0)
		goto out;
	fsidtype = simple_strtoul(buf, &ep, 10);
	if (*ep)
		goto out;
	dprintk("found fsidtype %d\n", fsidtype);
	if (fsidtype > 2)
		goto out;
	if ((len=qword_get(&mesg, buf, PAGE_SIZE)) <= 0)
		goto out;
	dprintk("found fsid length %d\n", len);
	if (len != key_len(fsidtype))
		goto out;

	/* OK, we seem to have a valid key */
	key.h.flags = 0;
	key.h.expiry_time = get_expiry(&mesg);
	if (key.h.expiry_time == 0)
		goto out;

	key.ek_client = dom;	
	key.ek_fsidtype = fsidtype;
	memcpy(key.ek_fsid, buf, len);

	/* now we want a pathname, or empty meaning NEGATIVE  */
	if ((len=qword_get(&mesg, buf, PAGE_SIZE)) < 0)
		goto out;
	dprintk("Path seems to be <%s>\n", buf);
	err = 0;
	if (len == 0) {
		struct svc_expkey *ek;
		set_bit(CACHE_NEGATIVE, &key.h.flags);
		ek = svc_expkey_lookup(&key, 1);
		if (ek)
			expkey_put(&ek->h, &svc_expkey_cache);
	} else {
		struct nameidata nd;
		struct svc_expkey *ek;
		struct svc_export *exp;
		err = path_lookup(buf, 0, &nd);
		if (err)
			goto out;

		dprintk("Found the path %s\n", buf);
		exp = exp_get_by_name(dom, nd.mnt, nd.dentry, NULL);

		err = -ENOENT;
		if (!exp)
			goto out_nd;
		key.ek_export = exp;
		dprintk("And found export\n");
		
		ek = svc_expkey_lookup(&key, 1);
		if (ek)
			expkey_put(&ek->h, &svc_expkey_cache);
		exp_put(exp);
		err = 0;
	out_nd:
		path_release(&nd);
	}
	cache_flush();
 out:
	if (dom)
		auth_domain_put(dom);
	if (buf)
		kfree(buf);
	return err;
}

static int expkey_show(struct seq_file *m,
		       struct cache_detail *cd,
		       struct cache_head *h)
{
	struct svc_expkey *ek ;

	if (h ==NULL) {
		seq_puts(m, "#domain fsidtype fsid [path]\n");
		return 0;
	}
	ek = container_of(h, struct svc_expkey, h);
	seq_printf(m, "%s %d 0x%08x", ek->ek_client->name,
		   ek->ek_fsidtype, ek->ek_fsid[0]);
	if (ek->ek_fsidtype != 1)
		seq_printf(m, "%08x", ek->ek_fsid[1]);
	if (ek->ek_fsidtype == 2)
		seq_printf(m, "%08x", ek->ek_fsid[2]);
	if (test_bit(CACHE_VALID, &h->flags) && 
	    !test_bit(CACHE_NEGATIVE, &h->flags)) {
		seq_printf(m, " ");
		seq_path(m, ek->ek_export->ex_mnt, ek->ek_export->ex_dentry, "\\ \t\n");
	}
	seq_printf(m, "\n");
	return 0;
}
	
struct cache_detail svc_expkey_cache = {
	.hash_size	= EXPKEY_HASHMAX,
	.hash_table	= expkey_table,
	.name		= "nfsd.fh",
	.cache_put	= expkey_put,
	.cache_request	= expkey_request,
	.cache_parse	= expkey_parse,
	.cache_show	= expkey_show,
};

static inline int svc_expkey_match (struct svc_expkey *a, struct svc_expkey *b)
{
	if (a->ek_fsidtype != b->ek_fsidtype ||
	    a->ek_client != b->ek_client ||
	    memcmp(a->ek_fsid, b->ek_fsid, key_len(a->ek_fsidtype)) != 0)
		return 0;
	return 1;
}

static inline void svc_expkey_init(struct svc_expkey *new, struct svc_expkey *item)
{
	cache_get(&item->ek_client->h);
	new->ek_client = item->ek_client;
	new->ek_fsidtype = item->ek_fsidtype;
	new->ek_fsid[0] = item->ek_fsid[0];
	new->ek_fsid[1] = item->ek_fsid[1];
	new->ek_fsid[2] = item->ek_fsid[2];
}

static inline void svc_expkey_update(struct svc_expkey *new, struct svc_expkey *item)
{
	cache_get(&item->ek_export->h);
	new->ek_export = item->ek_export;
}

static DefineSimpleCacheLookup(svc_expkey,0) /* no inplace updates */

#define	EXPORT_HASHBITS		8
#define	EXPORT_HASHMAX		(1<< EXPORT_HASHBITS)
#define	EXPORT_HASHMASK		(EXPORT_HASHMAX -1)

static struct cache_head *export_table[EXPORT_HASHMAX];

static inline int svc_export_hash(struct svc_export *item)
{
	int rv;

	rv = hash_ptr(item->ex_client, EXPORT_HASHBITS);
	rv ^= hash_ptr(item->ex_dentry, EXPORT_HASHBITS);
	rv ^= hash_ptr(item->ex_mnt, EXPORT_HASHBITS);
	return rv;
}

void svc_export_put(struct cache_head *item, struct cache_detail *cd)
{
	if (cache_put(item, cd)) {
		struct svc_export *exp = container_of(item, struct svc_export, h);
		dput(exp->ex_dentry);
		mntput(exp->ex_mnt);
		auth_domain_put(exp->ex_client);
		kfree(exp);
	}
}

void svc_export_request(struct cache_detail *cd,
			struct cache_head *h,
			char **bpp, int *blen)
{
	/*  client path */
	struct svc_export *exp = container_of(h, struct svc_export, h);
	char *pth;

	qword_add(bpp, blen, exp->ex_client->name);
	pth = d_path(exp->ex_dentry, exp->ex_mnt, *bpp, *blen);
	if (IS_ERR(pth)) {
		/* is this correct? */
		(*bpp)[0] = '\n';
		return;
	}
	qword_add(bpp, blen, pth);
	(*bpp)[-1] = '\n';
}

static struct svc_export *svc_export_lookup(struct svc_export *, int);

extern struct dentry *
find_exported_dentry(struct super_block *sb, void *obj, void *parent,
		     int (*acceptable)(void *context, struct dentry *de),
		     void *context);

static int check_export(struct inode *inode, int flags)
{

	/* We currently export only dirs and regular files.
	 * This is what umountd does.
	 */
	if (!S_ISDIR(inode->i_mode) &&
	    !S_ISREG(inode->i_mode))
		return -ENOTDIR;

	/* There are two requirements on a filesystem to be exportable.
	 * 1:  We must be able to identify the filesystem from a number.
	 *       either a device number (so FS_REQUIRES_DEV needed)
	 *       or an FSID number (so NFSEXP_FSID needed).
	 * 2:  We must be able to find an inode from a filehandle.
	 *       This means that s_export_op must be set.
	 */
	if (!(inode->i_sb->s_type->fs_flags & FS_REQUIRES_DEV) &&
	    !(flags & NFSEXP_FSID)) {
		dprintk("exp_export: export of non-dev fs without fsid");
		return -EINVAL;
	}
	if (!inode->i_sb->s_export_op) {
		dprintk("exp_export: export of invalid fs type.\n");
		return -EINVAL;
	}

	/* Ok, we can export it */;
	if (!inode->i_sb->s_export_op->find_exported_dentry)
		inode->i_sb->s_export_op->find_exported_dentry =
			find_exported_dentry;
	return 0;

}

int svc_export_parse(struct cache_detail *cd, char *mesg, int mlen)
{
	/* client path expiry [flags anonuid anongid fsid] */
	char *buf;
	int len;
	int err;
	struct auth_domain *dom = NULL;
	struct nameidata nd;
	struct svc_export exp, *expp;
	int an_int;

	nd.dentry = NULL;

	if (mesg[mlen-1] != '\n')
		return -EINVAL;
	mesg[mlen-1] = 0;

	buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
	err = -ENOMEM;
	if (!buf) goto out;

	/* client */
	len = qword_get(&mesg, buf, PAGE_SIZE);
	err = -EINVAL;
	if (len <= 0) goto out;

	err = -ENOENT;
	dom = auth_domain_find(buf);
	if (!dom)
		goto out;

	/* path */
	err = -EINVAL;
	if ((len=qword_get(&mesg, buf, PAGE_SIZE)) <= 0)
		goto out;
	err = path_lookup(buf, 0, &nd);
	if (err) goto out;

	exp.h.flags = 0;
	exp.ex_client = dom;
	exp.ex_mnt = nd.mnt;
	exp.ex_dentry = nd.dentry;

	/* expiry */
	err = -EINVAL;
	exp.h.expiry_time = get_expiry(&mesg);
	if (exp.h.expiry_time == 0)
		goto out;

	/* flags */
	err = get_int(&mesg, &an_int);
	if (err == -ENOENT)
		set_bit(CACHE_NEGATIVE, &exp.h.flags);
	else {
		if (err || an_int < 0) goto out;	
		exp.ex_flags= an_int;
	
		/* anon uid */
		err = get_int(&mesg, &an_int);
		if (err) goto out;
		exp.ex_anon_uid= an_int;

		/* anon gid */
		err = get_int(&mesg, &an_int);
		if (err) goto out;
		exp.ex_anon_gid= an_int;

		/* fsid */
		err = get_int(&mesg, &an_int);
		if (err) goto out;
		exp.ex_fsid = an_int;

		err = check_export(nd.dentry->d_inode, exp.ex_flags);
		if (err) goto out;
	}

	expp = svc_export_lookup(&exp, 1);
	if (expp)
		exp_put(expp);
	err = 0;
	cache_flush();
 out:
	if (nd.dentry)
		path_release(&nd);
	if (dom)
		auth_domain_put(dom);
	if (buf)
		kfree(buf);
	return err;
}

static void exp_flags(struct seq_file *m, int flag, int fsid, uid_t anonu, uid_t anong);

static int svc_export_show(struct seq_file *m,
			   struct cache_detail *cd,
			   struct cache_head *h)
{
	struct svc_export *exp ;

	if (h ==NULL) {
		seq_puts(m, "#path domain(flags)\n");
		return 0;
	}
	exp = container_of(h, struct svc_export, h);
	seq_path(m, exp->ex_mnt, exp->ex_dentry, " \t\n\\");
	seq_putc(m, '\t');
	seq_escape(m, exp->ex_client->name, " \t\n\\");
	seq_putc(m, '(');
	if (test_bit(CACHE_VALID, &h->flags) && 
	    !test_bit(CACHE_NEGATIVE, &h->flags))
		exp_flags(m, exp->ex_flags, exp->ex_fsid, 
			  exp->ex_anon_uid, exp->ex_anon_gid);
	seq_puts(m, ")\n");
	return 0;
}
struct cache_detail svc_export_cache = {
	.hash_size	= EXPORT_HASHMAX,
	.hash_table	= export_table,
	.name		= "nfsd.export",
	.cache_put	= svc_export_put,
	.cache_request	= svc_export_request,
	.cache_parse	= svc_export_parse,
	.cache_show	= svc_export_show,
};

static inline int svc_export_match(struct svc_export *a, struct svc_export *b)
{
	return a->ex_client == b->ex_client &&
		a->ex_dentry == b->ex_dentry &&
		a->ex_mnt == b->ex_mnt;
}
static inline void svc_export_init(struct svc_export *new, struct svc_export *item)
{
	cache_get(&item->ex_client->h);
	new->ex_client = item->ex_client;
	new->ex_dentry = dget(item->ex_dentry);
	new->ex_mnt = mntget(item->ex_mnt);
}

static inline void svc_export_update(struct svc_export *new, struct svc_export *item)
{
	new->ex_flags = item->ex_flags;
	new->ex_anon_uid = item->ex_anon_uid;
	new->ex_anon_gid = item->ex_anon_gid;
	new->ex_fsid = item->ex_fsid;
}

static DefineSimpleCacheLookup(svc_export,1) /* allow inplace updates */


struct svc_expkey *
exp_find_key(svc_client *clp, int fsid_type, u32 *fsidv, struct cache_req *reqp)
{
	struct svc_expkey key, *ek;
	int err;
	
	if (!clp)
		return NULL;

	key.ek_client = clp;
	key.ek_fsidtype = fsid_type;
	memcpy(key.ek_fsid, fsidv, key_len(fsid_type));

	ek = svc_expkey_lookup(&key, 0);
	if (ek != NULL)
		if ((err = cache_check(&svc_expkey_cache, &ek->h, reqp)))
			ek = ERR_PTR(err);
	return ek;
}

int exp_set_key(svc_client *clp, int fsid_type, u32 *fsidv, 
		struct svc_export *exp)
{
	struct svc_expkey key, *ek;

	key.ek_client = clp;
	key.ek_fsidtype = fsid_type;
	memcpy(key.ek_fsid, fsidv, key_len(fsid_type));
	key.ek_export = exp;
	key.h.expiry_time = NEVER;
	key.h.flags = 0;

	ek = svc_expkey_lookup(&key, 1);
	if (ek) {
		expkey_put(&ek->h, &svc_expkey_cache);
		return 0;
	}
	return -ENOMEM;
}

/*
 * Find the client's export entry matching xdev/xino.
 */
static inline struct svc_expkey *
exp_get_key(svc_client *clp, dev_t dev, ino_t ino)
{
	u32 fsidv[3];
	
	if (old_valid_dev(dev)) {
		mk_fsid_v0(fsidv, dev, ino);
		return exp_find_key(clp, 0, fsidv, NULL);
	}
	mk_fsid_v3(fsidv, dev, ino);
	return exp_find_key(clp, 3, fsidv, NULL);
}

/*
 * Find the client's export entry matching fsid
 */
static inline struct svc_expkey *
exp_get_fsid_key(svc_client *clp, int fsid)
{
	u32 fsidv[2];

	mk_fsid_v1(fsidv, fsid);

	return exp_find_key(clp, 1, fsidv, NULL);
}

svc_export *
exp_get_by_name(svc_client *clp, struct vfsmount *mnt, struct dentry *dentry,
		struct cache_req *reqp)
{
	struct svc_export *exp, key;
	
	if (!clp)
		return NULL;

	key.ex_client = clp;
	key.ex_mnt = mnt;
	key.ex_dentry = dentry;

	exp = svc_export_lookup(&key, 0);
	if (exp != NULL) 
		switch (cache_check(&svc_export_cache, &exp->h, reqp)) {
		case 0: break;
		case -EAGAIN:
			exp = ERR_PTR(-EAGAIN);
			break;
		default:
			exp = NULL;
		}

	return exp;
}

/*
 * Find the export entry for a given dentry.
 */
struct svc_export *
exp_parent(svc_client *clp, struct vfsmount *mnt, struct dentry *dentry,
	   struct cache_req *reqp)
{
	svc_export *exp;

	dget(dentry);