patch-2.4.20 linux-2.4.20/fs/xattr.c

• Lines: 356
• Date: Thu Nov 28 15:53:15 2002
• Orig file: linux-2.4.19/fs/xattr.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -urN linux-2.4.19/fs/xattr.c linux-2.4.20/fs/xattr.c
@@ -0,0 +1,355 @@
+/*
+  File: fs/xattr.c
+
+  Extended attribute handling.
+
+  Copyright (C) 2001 by Andreas Gruenbacher <a.gruenbacher@computer.org>
+  Copyright (C) 2001 SGI - Silicon Graphics, Inc <linux-xfs@oss.sgi.com>
+ */
+#include <linux/fs.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+#include <linux/smp_lock.h>
+#include <linux/file.h>
+#include <linux/xattr.h>
+#include <asm/uaccess.h>
+
+/*
+ * Extended attribute memory allocation wrappers, originally
+ * based on the Intermezzo PRESTO_ALLOC/PRESTO_FREE macros.
+ * The vmalloc use here is very uncommon - extended attributes
+ * are supposed to be small chunks of metadata, and it is quite
+ * unusual to have very many extended attributes, so lists tend
+ * to be quite short as well.  The 64K upper limit is derived
+ * from the extended attribute size limit used by XFS.
+ * Intentionally allow zero @size for value/list size requests.
+ */
+static void *
+xattr_alloc(size_t size, size_t limit)
+{
+	void *ptr;
+
+	if (size > limit)
+		return ERR_PTR(-E2BIG);
+
+	if (!size)	/* size request, no buffer is needed */
+		return NULL;
+	else if (size <= PAGE_SIZE)
+		ptr = kmalloc((unsigned long) size, GFP_KERNEL);
+	else
+		ptr = vmalloc((unsigned long) size);
+	if (!ptr)
+		return ERR_PTR(-ENOMEM);
+	return ptr;
+}
+
+static void
+xattr_free(void *ptr, size_t size)
+{
+	if (!size)	/* size request, no buffer was needed */
+		return;
+	else if (size <= PAGE_SIZE)
+		kfree(ptr);
+	else
+		vfree(ptr);
+}
+
+/*
+ * Extended attribute SET operations
+ */
+static long
+setxattr(struct dentry *d, char *name, void *value, size_t size, int flags)
+{
+	int error;
+	void *kvalue;
+	char kname[XATTR_NAME_MAX + 1];
+
+	if (flags & ~(XATTR_CREATE|XATTR_REPLACE))
+		return -EINVAL;
+
+	error = strncpy_from_user(kname, name, sizeof(kname));
+	if (error == 0 || error == sizeof(kname))
+		error = -ERANGE;
+	if (error < 0)
+		return error;
+
+	kvalue = xattr_alloc(size, XATTR_SIZE_MAX);
+	if (IS_ERR(kvalue))
+		return PTR_ERR(kvalue);
+
+	if (size > 0 && copy_from_user(kvalue, value, size)) {
+		xattr_free(kvalue, size);
+		return -EFAULT;
+	}
+
+	error = -EOPNOTSUPP;
+	if (d->d_inode->i_op && d->d_inode->i_op->setxattr) {
+		down(&d->d_inode->i_sem);
+		lock_kernel();
+		error = d->d_inode->i_op->setxattr(d, kname, kvalue, size, flags);
+		unlock_kernel();
+		up(&d->d_inode->i_sem);
+	}
+
+	xattr_free(kvalue, size);
+	return error;
+}
+
+asmlinkage long
+sys_setxattr(char *path, char *name, void *value, size_t size, int flags)
+{
+	struct nameidata nd;
+	int error;
+
+	error = user_path_walk(path, &nd);
+	if (error)
+		return error;
+	error = setxattr(nd.dentry, name, value, size, flags);
+	path_release(&nd);
+	return error;
+}
+
+asmlinkage long
+sys_lsetxattr(char *path, char *name, void *value, size_t size, int flags)
+{
+	struct nameidata nd;
+	int error;
+
+	error = user_path_walk_link(path, &nd);
+	if (error)
+		return error;
+	error = setxattr(nd.dentry, name, value, size, flags);
+	path_release(&nd);
+	return error;
+}
+
+asmlinkage long
+sys_fsetxattr(int fd, char *name, void *value, size_t size, int flags)
+{
+	struct file *f;
+	int error = -EBADF;
+
+	f = fget(fd);
+	if (!f)
+		return error;
+	error = setxattr(f->f_dentry, name, value, size, flags);
+	fput(f);
+	return error;
+}
+
+/*
+ * Extended attribute GET operations
+ */
+static ssize_t
+getxattr(struct dentry *d, char *name, void *value, size_t size)
+{
+	ssize_t error;
+	void *kvalue;
+	char kname[XATTR_NAME_MAX + 1];
+
+	error = strncpy_from_user(kname, name, sizeof(kname));
+	if (error == 0 || error == sizeof(kname))
+		error = -ERANGE;
+	if (error < 0)
+		return error;
+
+	kvalue = xattr_alloc(size, XATTR_SIZE_MAX);
+	if (IS_ERR(kvalue))
+		return PTR_ERR(kvalue);
+
+	error = -EOPNOTSUPP;
+	if (d->d_inode->i_op && d->d_inode->i_op->getxattr) {
+		down(&d->d_inode->i_sem);
+		lock_kernel();
+		error = d->d_inode->i_op->getxattr(d, kname, kvalue, size);
+		unlock_kernel();
+		up(&d->d_inode->i_sem);
+	}
+
+	if (kvalue && error > 0)
+		if (copy_to_user(value, kvalue, error))
+			error = -EFAULT;
+	xattr_free(kvalue, size);
+	return error;
+}
+
+asmlinkage ssize_t
+sys_getxattr(char *path, char *name, void *value, size_t size)
+{
+	struct nameidata nd;
+	ssize_t error;
+
+	error = user_path_walk(path, &nd);
+	if (error)
+		return error;
+	error = getxattr(nd.dentry, name, value, size);
+	path_release(&nd);
+	return error;
+}
+
+asmlinkage ssize_t
+sys_lgetxattr(char *path, char *name, void *value, size_t size)
+{
+	struct nameidata nd;
+	ssize_t error;
+
+	error = user_path_walk_link(path, &nd);
+	if (error)
+		return error;
+	error = getxattr(nd.dentry, name, value, size);
+	path_release(&nd);
+	return error;
+}
+
+asmlinkage ssize_t
+sys_fgetxattr(int fd, char *name, void *value, size_t size)
+{
+	struct file *f;
+	ssize_t error = -EBADF;
+
+	f = fget(fd);
+	if (!f)
+		return error;
+	error = getxattr(f->f_dentry, name, value, size);
+	fput(f);
+	return error;
+}
+
+/*
+ * Extended attribute LIST operations
+ */
+static ssize_t
+listxattr(struct dentry *d, char *list, size_t size)
+{
+	ssize_t error;
+	char *klist;
+
+	klist = (char *)xattr_alloc(size, XATTR_LIST_MAX);
+	if (IS_ERR(klist))
+		return PTR_ERR(klist);
+
+	error = -EOPNOTSUPP;
+	if (d->d_inode->i_op && d->d_inode->i_op->listxattr) {
+		down(&d->d_inode->i_sem);
+		lock_kernel();
+		error = d->d_inode->i_op->listxattr(d, klist, size);
+		unlock_kernel();
+		up(&d->d_inode->i_sem);
+	}
+
+	if (klist && error > 0)
+		if (copy_to_user(list, klist, error))
+			error = -EFAULT;
+	xattr_free(klist, size);
+	return error;
+}
+
+asmlinkage ssize_t
+sys_listxattr(char *path, char *list, size_t size)
+{
+	struct nameidata nd;
+	ssize_t error;
+
+	error = user_path_walk(path, &nd);
+	if (error)
+		return error;
+	error = listxattr(nd.dentry, list, size);
+	path_release(&nd);
+	return error;
+}
+
+asmlinkage ssize_t
+sys_llistxattr(char *path, char *list, size_t size)
+{
+	struct nameidata nd;
+	ssize_t error;
+
+	error = user_path_walk_link(path, &nd);
+	if (error)
+		return error;
+	error = listxattr(nd.dentry, list, size);
+	path_release(&nd);
+	return error;
+}
+
+asmlinkage ssize_t
+sys_flistxattr(int fd, char *list, size_t size)
+{
+	struct file *f;
+	ssize_t error = -EBADF;
+
+	f = fget(fd);
+	if (!f)
+		return error;
+	error = listxattr(f->f_dentry, list, size);
+	fput(f);
+	return error;
+}
+
+/*
+ * Extended attribute REMOVE operations
+ */
+static long
+removexattr(struct dentry *d, char *name)
+{
+	int error;
+	char kname[XATTR_NAME_MAX + 1];
+
+	error = strncpy_from_user(kname, name, sizeof(kname));
+	if (error == 0 || error == sizeof(kname))
+		error = -ERANGE;
+	if (error < 0)
+		return error;
+
+	error = -EOPNOTSUPP;
+	if (d->d_inode->i_op && d->d_inode->i_op->removexattr) {
+		down(&d->d_inode->i_sem);
+		lock_kernel();
+		error = d->d_inode->i_op->removexattr(d, kname);
+		unlock_kernel();
+		up(&d->d_inode->i_sem);
+	}
+	return error;
+}
+
+asmlinkage long
+sys_removexattr(char *path, char *name)
+{
+	struct nameidata nd;
+	int error;
+
+	error = user_path_walk(path, &nd);
+	if (error)
+		return error;
+	error = removexattr(nd.dentry, name);
+	path_release(&nd);
+	return error;
+}
+
+asmlinkage long
+sys_lremovexattr(char *path, char *name)
+{
+	struct nameidata nd;
+	int error;
+
+	error = user_path_walk_link(path, &nd);
+	if (error)
+		return error;
+	error = removexattr(nd.dentry, name);
+	path_release(&nd);
+	return error;
+}
+
+asmlinkage long
+sys_fremovexattr(int fd, char *name)
+{
+	struct file *f;
+	int error = -EBADF;
+
+	f = fget(fd);
+	if (!f)
+		return error;
+	error = removexattr(f->f_dentry, name);
+	fput(f);
+	return error;
+}