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Diffstat (limited to 'fs/sdcardfs/multiuser.h')
| -rw-r--r-- | fs/sdcardfs/multiuser.h | 37 |
1 files changed, 37 insertions, 0 deletions
diff --git a/fs/sdcardfs/multiuser.h b/fs/sdcardfs/multiuser.h new file mode 100644 index 000000000000..923ba101dfa9 --- /dev/null +++ b/fs/sdcardfs/multiuser.h @@ -0,0 +1,37 @@ +/* + * fs/sdcardfs/multiuser.h + * + * Copyright (c) 2013 Samsung Electronics Co. Ltd + * Authors: Daeho Jeong, Woojoong Lee, Seunghwan Hyun, + * Sunghwan Yun, Sungjong Seo + * + * This program has been developed as a stackable file system based on + * the WrapFS which written by + * + * Copyright (c) 1998-2011 Erez Zadok + * Copyright (c) 2009 Shrikar Archak + * Copyright (c) 2003-2011 Stony Brook University + * Copyright (c) 2003-2011 The Research Foundation of SUNY + * + * This file is dual licensed. It may be redistributed and/or modified + * under the terms of the Apache 2.0 License OR version 2 of the GNU + * General Public License. + */ + +#define MULTIUSER_APP_PER_USER_RANGE 100000 + +typedef uid_t userid_t; +typedef uid_t appid_t; + +static inline userid_t multiuser_get_user_id(uid_t uid) { + return uid / MULTIUSER_APP_PER_USER_RANGE; +} + +static inline appid_t multiuser_get_app_id(uid_t uid) { + return uid % MULTIUSER_APP_PER_USER_RANGE; +} + +static inline uid_t multiuser_get_uid(userid_t userId, appid_t appId) { + return userId * MULTIUSER_APP_PER_USER_RANGE + (appId % MULTIUSER_APP_PER_USER_RANGE); +} + |