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Commit fa164739 authored by Jeff Sharkey's avatar Jeff Sharkey
Browse files

Allocate a GID range for external cache files. 

We can't reuse the GID range for internal cache files, otherwise
we don't have a way to tease apart the difference when deciding if
it's safe to move apps.

Test: builds, boots
Bug: 37193650
Change-Id: I22c4e575cd557636e74c5c73035adb1d4dcbb7f7
parent 66f44d82

libcutils/include/cutils/multiuser.h

+1 −0
Original line number Diff line number Diff line
@@ -33,6 +33,7 @@ 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_ext_cache_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() */

libcutils/include/private/android_filesystem_config.h

+3 −0
Original line number Diff line number Diff line
@@ -171,6 +171,9 @@ 
#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_EXT_CACHE_GID_START 40000 /* start of gids for apps to mark external cached data */

#define AID_EXT_CACHE_GID_END 49999   /* end of gids for apps to mark external cached 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
@@ -45,6 +45,14 @@ gid_t multiuser_get_ext_gid(userid_t user_id, appid_t app_id) { 
    }

}



gid_t multiuser_get_ext_cache_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_CACHE_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
@@ -68,6 +68,14 @@ TEST(MultiuserTest, TestExt) { 
    EXPECT_EQ(1030000U, multiuser_get_ext_gid(10, 10000));

}



TEST(MultiuserTest, TestExtCache) {

    EXPECT_EQ(ERR_GID, multiuser_get_ext_cache_gid(0, 0));

    EXPECT_EQ(ERR_GID, multiuser_get_ext_cache_gid(0, 1000));

    EXPECT_EQ(40000U, multiuser_get_ext_cache_gid(0, 10000));

    EXPECT_EQ(ERR_GID, multiuser_get_ext_cache_gid(0, 50000));

    EXPECT_EQ(1040000U, multiuser_get_ext_cache_gid(10, 10000));

}



TEST(MultiuserTest, TestShared) {

    EXPECT_EQ(ERR_GID, multiuser_get_shared_gid(0, 0));

    EXPECT_EQ(ERR_GID, multiuser_get_shared_gid(0, 1000));