Add fs/jfs/acl.c

This file was somehow skipped (along with jfs_acl.h> when I checked in
the ACL support.

fs/jfs/acl.c

+/*
+ *   Copyright (c) International Business Machines  Corp., 2002
+ *   Copyright (c) Andreas Gruenbacher, 2001
+ *   Copyright (c) Linus Torvalds, 1991, 1992
+ *
+ *   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.
+ * 
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY;  without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
+ *   the GNU General Public License for more details.
+ *
+ *   You should have received a copy of the GNU General Public License
+ *   along with this program;  if not, write to the Free Software 
+ *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#include <linux/sched.h>
+#include <linux/fs.h>
+#include "jfs_incore.h"
+#include "jfs_xattr.h"
+#include "jfs_acl.h"
+
+struct posix_acl *jfs_get_acl(struct inode *inode, int type)
+{
+	struct posix_acl *acl;
+	char *ea_name;
+	struct jfs_inode_info *ji = JFS_IP(inode);
+	struct posix_acl **p_acl;
+	int size;
+	char *value = NULL;
+
+	switch(type) {
+		case ACL_TYPE_ACCESS:
+			ea_name = XATTR_NAME_ACL_ACCESS;
+			p_acl = &ji->i_acl;
+			break;
+		case ACL_TYPE_DEFAULT:
+			ea_name = XATTR_NAME_ACL_DEFAULT;
+			p_acl = &ji->i_default_acl;
+			break;
+		default:
+			return ERR_PTR(-EINVAL);
+	}
+
+	if (*p_acl != JFS_ACL_NOT_CACHED)
+		return posix_acl_dup(*p_acl);
+
+	size = __jfs_getxattr(inode, ea_name, NULL, 0);
+
+	if (size > 0) {
+		value = kmalloc(size, GFP_KERNEL);
+		if (!value)
+			return ERR_PTR(-ENOMEM);
+		size = __jfs_getxattr(inode, ea_name, value, size);
+	}
+
+	if (size < 0) {
+		if (size == -ENODATA) {
+			*p_acl = NULL;
+			acl = NULL;
+		} else
+			acl = ERR_PTR(size);
+	} else {
+		acl = posix_acl_from_xattr(value, size);
+		if (!IS_ERR(acl))
+			*p_acl = posix_acl_dup(acl);
+	}
+	if (value)
+		kfree(value);
+	return acl;
+}
+
+int jfs_set_acl(struct inode *inode, int type, struct posix_acl *acl)
+{
+	char *ea_name;
+	struct jfs_inode_info *ji = JFS_IP(inode);
+	struct posix_acl **p_acl;
+	int rc;
+	int size = 0;
+	char *value = NULL;
+
+	if (S_ISLNK(inode->i_mode))
+		return -EOPNOTSUPP;
+
+	switch(type) {
+		case ACL_TYPE_ACCESS:
+			ea_name = XATTR_NAME_ACL_ACCESS;
+			p_acl = &ji->i_acl;
+			break;
+		case ACL_TYPE_DEFAULT:
+			ea_name = XATTR_NAME_ACL_DEFAULT;
+			p_acl = &ji->i_default_acl;
+			if (!S_ISDIR(inode->i_mode))
+				return acl ? -EACCES : 0;
+			break;
+		default:
+			return -EINVAL;
+	}
+	if (acl) {
+		size = xattr_acl_size(acl->a_count);
+		value = kmalloc(size, GFP_KERNEL);
+		if (!value)
+			return -ENOMEM;
+		rc = posix_acl_to_xattr(acl, value, size);
+		if (rc < 0)
+			goto out;
+	}
+	rc = __jfs_setxattr(inode, ea_name, value, size, 0);
+out:
+	if (value)
+		kfree(value);
+
+	if (!rc) {
+		if (*p_acl && (*p_acl != JFS_ACL_NOT_CACHED))
+			posix_acl_release(*p_acl);
+		*p_acl = posix_acl_dup(acl);
+	}
+	return rc;
+}
+
+/*
+ *	__jfs_permission()
+ *
+ * modified vfs_permission to check posix acl
+ */
+static int __jfs_permission(struct inode * inode, int mask, int have_sem)
+{
+	umode_t mode = inode->i_mode;
+	struct jfs_inode_info *ji = JFS_IP(inode);
+
+	if (mask & MAY_WRITE) {
+		/*
+		 * Nobody gets write access to a read-only fs.
+		 */
+		if (IS_RDONLY(inode) &&
+		    (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode)))
+			return -EROFS;
+
+		/*
+		 * Nobody gets write access to an immutable file.
+		 */
+		if (IS_IMMUTABLE(inode))
+			return -EACCES;
+	}
+
+	if (current->fsuid == inode->i_uid) {
+		mode >>= 6;
+		goto check_mode;
+	}
+	/*
+	 * ACL can't contain additional permissions if the ACL_MASK entry
+	 * is zero.
+	 */
+	if (!(mode & S_IRWXG))
+		goto check_groups;
+
+	if (ji->i_acl == JFS_ACL_NOT_CACHED) {
+		struct posix_acl *acl;
+
+		if (!have_sem)
+			down(&inode->i_sem);
+		acl = jfs_get_acl(inode, ACL_TYPE_ACCESS);
+		if (!have_sem)
+			up(&inode->i_sem);
+
+		if (IS_ERR(acl))
+			return PTR_ERR(acl);
+		posix_acl_release(acl);
+	}
+
+	if (ji->i_acl) {
+		int rc = posix_acl_permission(inode, ji->i_acl, mask);
+		if (rc == -EACCES)
+			goto check_capabilities;
+		return rc;
+	}
+
+check_groups:
+	if (in_group_p(inode->i_gid))
+		mode >>= 3;
+
+check_mode:
+	/*
+	 * If the DACs are ok we don't need any capability check.
+	 */
+	if (((mode & mask & (MAY_READ|MAY_WRITE|MAY_EXEC)) == mask))
+		return 0;
+
+check_capabilities:
+	/*
+	 * Read/write DACs are always overridable.
+	 * Executable DACs are overridable if at least one exec bit is set.
+	 */
+	if ((mask & (MAY_READ|MAY_WRITE)) || (inode->i_mode & S_IXUGO))
+		if (capable(CAP_DAC_OVERRIDE))
+			return 0;
+
+	/*
+	 * Searching includes executable on directories, else just read.
+	 */
+	if (mask == MAY_READ || (S_ISDIR(inode->i_mode) && !(mask & MAY_WRITE)))
+		if (capable(CAP_DAC_READ_SEARCH))
+			return 0;
+
+	return -EACCES;
+}
+int jfs_permission(struct inode * inode, int mask)
+{
+	return __jfs_permission(inode, mask, 0);
+}
+int jfs_permission_have_sem(struct inode * inode, int mask)
+{
+	return __jfs_permission(inode, mask, 1);
+}
+
+int jfs_init_acl(struct inode *inode, struct inode *dir)
+{
+	struct posix_acl *acl = NULL;
+	struct posix_acl *clone;
+	mode_t mode;
+	int rc = 0;
+
+	if (S_ISLNK(inode->i_mode))
+		return 0;
+
+	acl = jfs_get_acl(dir, ACL_TYPE_DEFAULT);
+	if (IS_ERR(acl))
+		return PTR_ERR(acl);
+
+	if (acl) {
+		if (S_ISDIR(inode->i_mode)) {
+			rc = jfs_set_acl(inode, ACL_TYPE_DEFAULT, acl);
+			if (rc)
+				goto cleanup;
+		}
+		clone = posix_acl_clone(acl, GFP_KERNEL);
+		if (!clone) {
+			rc = -ENOMEM;
+			goto cleanup;
+		}
+		mode = inode->i_mode;
+		rc = posix_acl_create_masq(clone, &mode);
+		if (rc >= 0) {
+			inode->i_mode = mode;
+			if (rc > 0)
+				rc = jfs_set_acl(inode, ACL_TYPE_ACCESS, clone);
+		}
+		posix_acl_release(clone);
+cleanup:
+		posix_acl_release(acl);
+	} else
+		inode->i_mode &= ~current->fs->umask;
+
+	return rc;
+}
+
+int jfs_acl_chmod(struct inode *inode)
+{
+	struct posix_acl *acl, *clone;
+	int rc;
+
+	if (S_ISLNK(inode->i_mode))
+		return -EOPNOTSUPP;
+
+	acl = jfs_get_acl(inode, ACL_TYPE_ACCESS);
+	if (IS_ERR(acl) || !acl)
+		return PTR_ERR(acl);
+
+	clone = posix_acl_clone(acl, GFP_KERNEL);
+	posix_acl_release(acl);
+	if (!clone)
+		return -ENOMEM;
+
+	rc = posix_acl_chmod_masq(clone, inode->i_mode);
+	if (!rc)
+		rc = jfs_set_acl(inode, ACL_TYPE_ACCESS, clone);
+
+	posix_acl_release(clone);
+	return rc;
+}
+
+int jfs_setattr(struct dentry *dentry, struct iattr *iattr)
+{
+	struct inode *inode = dentry->d_inode;
+	int rc;
+
+	rc = inode_change_ok(inode, iattr);
+	if (rc)
+		return rc;
+
+	inode_setattr(inode, iattr);
+
+	if (iattr->ia_valid & ATTR_MODE)
+		rc = jfs_acl_chmod(inode);
+
+	return rc;
+}