initial_commit

1 files changed, 225 insertions, 0 deletions

diff --git a/fs/generic_acl.c b/fs/generic_acl.c
new file mode 100644
index 00000000..8f26d1a5
--- /dev/null
+++ b/fs/generic_acl.c
@@ -0,0 +1,225 @@
+/*
+ * (C) 2005 Andreas Gruenbacher <agruen@suse.de>
+ *
+ * This file is released under the GPL.
+ *
+ * Generic ACL support for in-memory filesystems.
+ */
+
+#include <linux/sched.h>
+#include <linux/gfp.h>
+#include <linux/fs.h>
+#include <linux/generic_acl.h>
+#include <linux/posix_acl.h>
+#include <linux/posix_acl_xattr.h>
+
+
+static size_t
+generic_acl_list(struct dentry *dentry, char *list, size_t list_size,
+		const char *name, size_t name_len, int type)
+{
+	struct posix_acl *acl;
+	const char *xname;
+	size_t size;
+
+	acl = get_cached_acl(dentry->d_inode, type);
+	if (!acl)
+		return 0;
+	posix_acl_release(acl);
+
+	switch (type) {
+	case ACL_TYPE_ACCESS:
+		xname = POSIX_ACL_XATTR_ACCESS;
+		break;
+	case ACL_TYPE_DEFAULT:
+		xname = POSIX_ACL_XATTR_DEFAULT;
+		break;
+	default:
+		return 0;
+	}
+	size = strlen(xname) + 1;
+	if (list && size <= list_size)
+		memcpy(list, xname, size);
+	return size;
+}
+
+static int
+generic_acl_get(struct dentry *dentry, const char *name, void *buffer,
+		     size_t size, int type)
+{
+	struct posix_acl *acl;
+	int error;
+
+	if (strcmp(name, "") != 0)
+		return -EINVAL;
+
+	acl = get_cached_acl(dentry->d_inode, type);
+	if (!acl)
+		return -ENODATA;
+	error = posix_acl_to_xattr(acl, buffer, size);
+	posix_acl_release(acl);
+
+	return error;
+}
+
+static int
+generic_acl_set(struct dentry *dentry, const char *name, const void *value,
+		     size_t size, int flags, int type)
+{
+	struct inode *inode = dentry->d_inode;
+	struct posix_acl *acl = NULL;
+	int error;
+
+	if (strcmp(name, "") != 0)
+		return -EINVAL;
+	if (S_ISLNK(inode->i_mode))
+		return -EOPNOTSUPP;
+	if (!inode_owner_or_capable(inode))
+		return -EPERM;
+	if (value) {
+		acl = posix_acl_from_xattr(value, size);
+		if (IS_ERR(acl))
+			return PTR_ERR(acl);
+	}
+	if (acl) {
+		mode_t mode;
+
+		error = posix_acl_valid(acl);
+		if (error)
+			goto failed;
+		switch (type) {
+		case ACL_TYPE_ACCESS:
+			mode = inode->i_mode;
+			error = posix_acl_equiv_mode(acl, &mode);
+			if (error < 0)
+				goto failed;
+			inode->i_mode = mode;
+			inode->i_ctime = CURRENT_TIME;
+			if (error == 0) {
+				posix_acl_release(acl);
+				acl = NULL;
+			}
+			break;
+		case ACL_TYPE_DEFAULT:
+			if (!S_ISDIR(inode->i_mode)) {
+				error = -EINVAL;
+				goto failed;
+			}
+			break;
+		}
+	}
+	set_cached_acl(inode, type, acl);
+	error = 0;
+failed:
+	posix_acl_release(acl);
+	return error;
+}
+
+/**
+ * generic_acl_init  -  Take care of acl inheritance at @inode create time
+ *
+ * Files created inside a directory with a default ACL inherit the
+ * directory's default ACL.
+ */
+int
+generic_acl_init(struct inode *inode, struct inode *dir)
+{
+	struct posix_acl *acl = NULL;
+	mode_t mode = inode->i_mode;
+	int error;
+
+	inode->i_mode = mode & ~current_umask();
+	if (!S_ISLNK(inode->i_mode))
+		acl = get_cached_acl(dir, ACL_TYPE_DEFAULT);
+	if (acl) {
+		struct posix_acl *clone;
+
+		if (S_ISDIR(inode->i_mode)) {
+			clone = posix_acl_clone(acl, GFP_KERNEL);
+			error = -ENOMEM;
+			if (!clone)
+				goto cleanup;
+			set_cached_acl(inode, ACL_TYPE_DEFAULT, clone);
+			posix_acl_release(clone);
+		}
+		clone = posix_acl_clone(acl, GFP_KERNEL);
+		error = -ENOMEM;
+		if (!clone)
+			goto cleanup;
+		error = posix_acl_create_masq(clone, &mode);
+		if (error >= 0) {
+			inode->i_mode = mode;
+			if (error > 0)
+				set_cached_acl(inode, ACL_TYPE_ACCESS, clone);
+		}
+		posix_acl_release(clone);
+	}
+	error = 0;
+
+cleanup:
+	posix_acl_release(acl);
+	return error;
+}
+
+/**
+ * generic_acl_chmod  -  change the access acl of @inode upon chmod()
+ *
+ * A chmod also changes the permissions of the owner, group/mask, and
+ * other ACL entries.
+ */
+int
+generic_acl_chmod(struct inode *inode)
+{
+	struct posix_acl *acl, *clone;
+	int error = 0;
+
+	if (S_ISLNK(inode->i_mode))
+		return -EOPNOTSUPP;
+	acl = get_cached_acl(inode, ACL_TYPE_ACCESS);
+	if (acl) {
+		clone = posix_acl_clone(acl, GFP_KERNEL);
+		posix_acl_release(acl);
+		if (!clone)
+			return -ENOMEM;
+		error = posix_acl_chmod_masq(clone, inode->i_mode);
+		if (!error)
+			set_cached_acl(inode, ACL_TYPE_ACCESS, clone);
+		posix_acl_release(clone);
+	}
+	return error;
+}
+
+int
+generic_check_acl(struct inode *inode, int mask, unsigned int flags)
+{
+	if (flags & IPERM_FLAG_RCU) {
+		if (!negative_cached_acl(inode, ACL_TYPE_ACCESS))
+			return -ECHILD;
+	} else {
+		struct posix_acl *acl;
+
+		acl = get_cached_acl(inode, ACL_TYPE_ACCESS);
+		if (acl) {
+			int error = posix_acl_permission(inode, acl, mask);
+			posix_acl_release(acl);
+			return error;
+		}
+	}
+	return -EAGAIN;
+}
+
+const struct xattr_handler generic_acl_access_handler = {
+	.prefix = POSIX_ACL_XATTR_ACCESS,
+	.flags	= ACL_TYPE_ACCESS,
+	.list	= generic_acl_list,
+	.get	= generic_acl_get,
+	.set	= generic_acl_set,
+};
+
+const struct xattr_handler generic_acl_default_handler = {
+	.prefix = POSIX_ACL_XATTR_DEFAULT,
+	.flags	= ACL_TYPE_DEFAULT,
+	.list	= generic_acl_list,
+	.get	= generic_acl_get,
+	.set	= generic_acl_set,
+};