hfsplus: implement POSIX ACLs support

Implement POSIX ACLs support in hfsplus driver.

Signed-off-by: Vyacheslav Dubeyko <slava@dubeyko.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Hin-Tak Leung <htl10@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/fs/hfsplus/posix_acl.c b/fs/hfsplus/posix_acl.c
new file mode 100644 (file)
index 0000000..b609cc1
--- /dev/null
+++ b/fs/hfsplus/posix_acl.c
@@ -0,0 +1,274 @@
+/*
+ * linux/fs/hfsplus/posix_acl.c
+ *
+ * Vyacheslav Dubeyko <slava@dubeyko.com>
+ *
+ * Handler for Posix Access Control Lists (ACLs) support.
+ */
+
+#include "hfsplus_fs.h"
+#include "xattr.h"
+#include "acl.h"
+
+struct posix_acl *hfsplus_get_posix_acl(struct inode *inode, int type)
+{
+       struct posix_acl *acl;
+       char *xattr_name;
+       char *value = NULL;
+       ssize_t size;
+
+       acl = get_cached_acl(inode, type);
+       if (acl != ACL_NOT_CACHED)
+               return acl;
+
+       switch (type) {
+       case ACL_TYPE_ACCESS:
+               xattr_name = POSIX_ACL_XATTR_ACCESS;
+               break;
+       case ACL_TYPE_DEFAULT:
+               xattr_name = POSIX_ACL_XATTR_DEFAULT;
+               break;
+       default:
+               return ERR_PTR(-EINVAL);
+       }
+
+       size = __hfsplus_getxattr(inode, xattr_name, NULL, 0);
+
+       if (size > 0) {
+               value = (char *)hfsplus_alloc_attr_entry();
+               if (unlikely(!value))
+                       return ERR_PTR(-ENOMEM);
+               size = __hfsplus_getxattr(inode, xattr_name, value, size);
+       }
+
+       if (size > 0)
+               acl = posix_acl_from_xattr(&init_user_ns, value, size);
+       else if (size == -ENODATA)
+               acl = NULL;
+       else
+               acl = ERR_PTR(size);
+
+       hfsplus_destroy_attr_entry((hfsplus_attr_entry *)value);
+
+       if (!IS_ERR(acl))
+               set_cached_acl(inode, type, acl);
+
+       return acl;
+}
+
+static int hfsplus_set_posix_acl(struct inode *inode,
+                                       int type,
+                                       struct posix_acl *acl)
+{
+       int err;
+       char *xattr_name;
+       size_t size = 0;
+       char *value = NULL;
+
+       if (S_ISLNK(inode->i_mode))
+               return -EOPNOTSUPP;
+
+       switch (type) {
+       case ACL_TYPE_ACCESS:
+               xattr_name = POSIX_ACL_XATTR_ACCESS;
+               if (acl) {
+                       err = posix_acl_equiv_mode(acl, &inode->i_mode);
+                       if (err < 0)
+                               return err;
+               }
+               err = 0;
+               break;
+
+       case ACL_TYPE_DEFAULT:
+               xattr_name = POSIX_ACL_XATTR_DEFAULT;
+               if (!S_ISDIR(inode->i_mode))
+                       return acl ? -EACCES : 0;
+               break;
+
+       default:
+               return -EINVAL;
+       }
+
+       if (acl) {
+               size = posix_acl_xattr_size(acl->a_count);
+               if (unlikely(size > HFSPLUS_MAX_INLINE_DATA_SIZE))
+                       return -ENOMEM;
+               value = (char *)hfsplus_alloc_attr_entry();
+               if (unlikely(!value))
+                       return -ENOMEM;
+               err = posix_acl_to_xattr(&init_user_ns, acl, value, size);
+               if (unlikely(err < 0))
+                       goto end_set_acl;
+       }
+
+       err = __hfsplus_setxattr(inode, xattr_name, value, size, 0);
+
+end_set_acl:
+       hfsplus_destroy_attr_entry((hfsplus_attr_entry *)value);
+
+       if (!err)
+               set_cached_acl(inode, type, acl);
+
+       return err;
+}
+
+int hfsplus_init_posix_acl(struct inode *inode, struct inode *dir)
+{
+       int err = 0;
+       struct posix_acl *acl = NULL;
+
+       hfs_dbg(ACL_MOD,
+               "[%s]: ino %lu, dir->ino %lu\n",
+               __func__, inode->i_ino, dir->i_ino);
+
+       if (S_ISLNK(inode->i_mode))
+               return 0;
+
+       acl = hfsplus_get_posix_acl(dir, ACL_TYPE_DEFAULT);
+       if (IS_ERR(acl))
+               return PTR_ERR(acl);
+
+       if (acl) {
+               if (S_ISDIR(inode->i_mode)) {
+                       err = hfsplus_set_posix_acl(inode,
+                                                       ACL_TYPE_DEFAULT,
+                                                       acl);
+                       if (unlikely(err))
+                               goto init_acl_cleanup;
+               }
+
+               err = posix_acl_create(&acl, GFP_NOFS, &inode->i_mode);
+               if (unlikely(err < 0))
+                       return err;
+
+               if (err > 0)
+                       err = hfsplus_set_posix_acl(inode,
+                                                       ACL_TYPE_ACCESS,
+                                                       acl);
+       } else
+               inode->i_mode &= ~current_umask();
+
+init_acl_cleanup:
+       posix_acl_release(acl);
+       return err;
+}
+
+int hfsplus_posix_acl_chmod(struct inode *inode)
+{
+       int err;
+       struct posix_acl *acl;
+
+       hfs_dbg(ACL_MOD, "[%s]: ino %lu\n", __func__, inode->i_ino);
+
+       if (S_ISLNK(inode->i_mode))
+               return -EOPNOTSUPP;
+
+       acl = hfsplus_get_posix_acl(inode, ACL_TYPE_ACCESS);
+       if (IS_ERR(acl) || !acl)
+               return PTR_ERR(acl);
+
+       err = posix_acl_chmod(&acl, GFP_KERNEL, inode->i_mode);
+       if (unlikely(err))
+               return err;
+
+       err = hfsplus_set_posix_acl(inode, ACL_TYPE_ACCESS, acl);
+       posix_acl_release(acl);
+       return err;
+}
+
+static int hfsplus_xattr_get_posix_acl(struct dentry *dentry,
+                                       const char *name,
+                                       void *buffer,
+                                       size_t size,
+                                       int type)
+{
+       int err = 0;
+       struct posix_acl *acl;
+
+       hfs_dbg(ACL_MOD,
+               "[%s]: ino %lu, buffer %p, size %zu, type %#x\n",
+               __func__, dentry->d_inode->i_ino, buffer, size, type);
+
+       if (strcmp(name, "") != 0)
+               return -EINVAL;
+
+       acl = hfsplus_get_posix_acl(dentry->d_inode, type);
+       if (IS_ERR(acl))
+               return PTR_ERR(acl);
+       if (acl == NULL)
+               return -ENODATA;
+
+       err = posix_acl_to_xattr(&init_user_ns, acl, buffer, size);
+       posix_acl_release(acl);
+
+       return err;
+}
+
+static int hfsplus_xattr_set_posix_acl(struct dentry *dentry,
+                                       const char *name,
+                                       const void *value,
+                                       size_t size,
+                                       int flags,
+                                       int type)
+{
+       int err = 0;
+       struct inode *inode = dentry->d_inode;
+       struct posix_acl *acl = NULL;
+
+       hfs_dbg(ACL_MOD,
+               "[%s]: ino %lu, value %p, size %zu, flags %#x, type %#x\n",
+               __func__, inode->i_ino, value, size, flags, type);
+
+       if (strcmp(name, "") != 0)
+               return -EINVAL;
+
+       if (!inode_owner_or_capable(inode))
+               return -EPERM;
+
+       if (value) {
+               acl = posix_acl_from_xattr(&init_user_ns, value, size);
+               if (IS_ERR(acl))
+                       return PTR_ERR(acl);
+               else if (acl) {
+                       err = posix_acl_valid(acl);
+                       if (err)
+                               goto end_xattr_set_acl;
+               }
+       }
+
+       err = hfsplus_set_posix_acl(inode, type, acl);
+
+end_xattr_set_acl:
+       posix_acl_release(acl);
+       return err;
+}
+
+static size_t hfsplus_xattr_list_posix_acl(struct dentry *dentry,
+                                               char *list,
+                                               size_t list_size,
+                                               const char *name,
+                                               size_t name_len,
+                                               int type)
+{
+       /*
+        * This method is not used.
+        * It is used hfsplus_listxattr() instead of generic_listxattr().
+        */
+       return -EOPNOTSUPP;
+}
+
+const struct xattr_handler hfsplus_xattr_acl_access_handler = {
+       .prefix = POSIX_ACL_XATTR_ACCESS,
+       .flags  = ACL_TYPE_ACCESS,
+       .list   = hfsplus_xattr_list_posix_acl,
+       .get    = hfsplus_xattr_get_posix_acl,
+       .set    = hfsplus_xattr_set_posix_acl,
+};
+
+const struct xattr_handler hfsplus_xattr_acl_default_handler = {
+       .prefix = POSIX_ACL_XATTR_DEFAULT,
+       .flags  = ACL_TYPE_DEFAULT,
+       .list   = hfsplus_xattr_list_posix_acl,
+       .get    = hfsplus_xattr_get_posix_acl,
+       .set    = hfsplus_xattr_set_posix_acl,
+};