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Commit 7e5d0b1f authored by Jeff Sharkey's avatar Jeff Sharkey
Browse files

Define GID range for external data and OBBs. 

To quickly answer the question of "how much data is a UID using?" we
need a GID range to label files on external storage, similar to
the GID ranges already defined for cached and shared data.

Also define a new GID that will be used to label the OBB files shared
between all users under /data/media/obb.

Test: builds, newly added tests pass
Bug: 34263266
Change-Id: I16fb7d166c3dcdeafbf477162d191d3b73ae8ac2
parent 230201dc

include/cutils/multiuser.h

+1 −0
Original line number Diff line number Diff line
@@ -32,6 +32,7 @@ extern appid_t multiuser_get_app_id(uid_t uid); 
extern uid_t multiuser_get_uid(userid_t user_id, appid_t app_id);



extern gid_t multiuser_get_cache_gid(userid_t user_id, appid_t app_id);

extern gid_t multiuser_get_ext_gid(userid_t user_id, appid_t app_id);

extern gid_t multiuser_get_shared_gid(userid_t user_id, appid_t app_id);



/* TODO: switch callers over to multiuser_get_shared_gid() */

include/private/android_filesystem_config.h

+4 −0
Original line number Diff line number Diff line
@@ -127,6 +127,7 @@ 
#define AID_MEDIA_VIDEO   1056 /* GID for video files on internal media storage */

#define AID_MEDIA_IMAGE   1057 /* GID for image files on internal media storage */

#define AID_TOMBSTONED    1058  /* tombstoned user */

#define AID_MEDIA_OBB     1059 /* GID for OBB files on internal media storage */

/* Changes to this file must be made in AOSP, *not* in internal branches. */



#define AID_SHELL         2000  /* adb and debug shell user */
@@ -165,6 +166,9 @@ 
#define AID_CACHE_GID_START  20000 /* start of gids for apps to mark cached data */

#define AID_CACHE_GID_END    29999 /* end of gids for apps to mark cached data */



#define AID_EXT_GID_START    30000 /* start of gids for apps to mark external data */

#define AID_EXT_GID_END      39999 /* end of gids for apps to mark external data */



#define AID_SHARED_GID_START 50000 /* start of gids for apps in each user to share */

#define AID_SHARED_GID_END   59999 /* end of gids for apps in each user to share */

libcutils/multiuser.c

+8 −0
Original line number Diff line number Diff line
@@ -37,6 +37,14 @@ gid_t multiuser_get_cache_gid(userid_t user_id, appid_t app_id) { 
    }

}



gid_t multiuser_get_ext_gid(userid_t user_id, appid_t app_id) {

    if (app_id >= AID_APP_START && app_id <= AID_APP_END) {

        return multiuser_get_uid(user_id, (app_id - AID_APP_START) + AID_EXT_GID_START);

    } else {

        return -1;

    }

}



gid_t multiuser_get_shared_gid(userid_t user_id, appid_t app_id) {

    if (app_id >= AID_APP_START && app_id <= AID_APP_END) {

        return multiuser_get_uid(user_id, (app_id - AID_APP_START) + AID_SHARED_GID_START);

libcutils/tests/multiuser_test.cpp

+8 −0
Original line number Diff line number Diff line
@@ -58,6 +58,14 @@ TEST(MultiuserTest, TestCache) { 
    EXPECT_EQ(1020000, multiuser_get_cache_gid(10, 10000));

}



TEST(MultiuserTest, TestExt) {

    EXPECT_EQ(-1, multiuser_get_ext_gid(0, 0));

    EXPECT_EQ(-1, multiuser_get_ext_gid(0, 1000));

    EXPECT_EQ(30000, multiuser_get_ext_gid(0, 10000));

    EXPECT_EQ(-1, multiuser_get_ext_gid(0, 50000));

    EXPECT_EQ(1030000, multiuser_get_ext_gid(10, 10000));

}



TEST(MultiuserTest, TestShared) {

    EXPECT_EQ(-1, multiuser_get_shared_gid(0, 0));

    EXPECT_EQ(-1, multiuser_get_shared_gid(0, 1000));