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Commit 885342a0 authored by Jeff Sharkey's avatar Jeff Sharkey
Browse files

Multi-user external storage support. 

Remount rootfs as recursively shared, so that mount changes are
propagated into child namespaces.  Mount external storage for access
from adb.

Clean multi-user dependencies for use in Dalvik.  Also define
external storage paths.

Bug: 6925012
Change-Id: I375de581a63f4f36667894c56a34a9dd45361e8f
parent e50ac5f7

adb/adb.c

+23 −1
Original line number Diff line number Diff line
@@ -35,6 +35,7 @@ 
#include <private/android_filesystem_config.h>

#include <linux/capability.h>

#include <linux/prctl.h>

#include <sys/mount.h>

#else

#include "usb_vendors.h"

#endif
@@ -989,6 +990,26 @@ static int should_drop_privileges() { 
}

#endif /* !ADB_HOST */



#if !ADB_HOST

/* Give ourselves access to external storage, which is otherwise protected. */

static void mount_external_storage(void) {

    // Create private mount namespace for our process

    if (unshare(CLONE_NEWNS) == -1) {

        fatal_errno("Failed to unshare()");

    }



    // Mark rootfs as being a slave in our process so that changes

    // from parent namespace flow into our process.

    if (mount("rootfs", "/", NULL, (MS_SLAVE | MS_REC), NULL) == -1) {

        fatal_errno("Failed to mount() rootfs as MS_SLAVE");

    }



    if (mount(EXTERNAL_STORAGE_SYSTEM, EXTERNAL_STORAGE_APP, "none", MS_BIND, NULL) == -1) {

        fatal_errno("Failed to mount() from %s", EXTERNAL_STORAGE_SYSTEM);

    }

}

#endif /* !ADB_HOST */



int adb_main(int is_daemon, int server_port)

{

#if !ADB_HOST
@@ -1008,7 +1029,6 @@ int adb_main(int is_daemon, int server_port) 


    init_transport_registration();





#if ADB_HOST

    HOST = 1;

    usb_vendors_init();
@@ -1022,6 +1042,8 @@ int adb_main(int is_daemon, int server_port) 
    }

#else



    mount_external_storage();



    /* don't listen on a port (default 5037) if running in secure mode */

    /* don't run as root if we are running in secure mode */

    if (should_drop_privileges()) {

include/cutils/multiuser.h

+3 −3
Original line number Diff line number Diff line
@@ -30,9 +30,9 @@ extern "C" { 
typedef uid_t userid_t;

typedef uid_t appid_t;



extern userid_t getUserId(uid_t uid);

extern appid_t getAppId(uid_t uid);

extern uid_t getUid(userid_t userId, appid_t appId);

extern userid_t multiuser_getUserId(uid_t uid);

extern appid_t multiuser_getAppId(uid_t uid);

extern uid_t multiuser_getUid(userid_t userId, appid_t appId);



#ifdef __cplusplus

}

include/private/android_filesystem_config.h

+3 −0
Original line number Diff line number Diff line
@@ -229,6 +229,9 @@ static struct fs_path_config android_files[] = { 
    { 00644, AID_ROOT,      AID_ROOT,       0 },

};



#define EXTERNAL_STORAGE_SYSTEM "/mnt/secure/sdcard0"

#define EXTERNAL_STORAGE_APP "/storage/sdcard0"



static inline void fs_config(const char *path, int dir,

                             unsigned *uid, unsigned *gid, unsigned *mode)

{

libcutils/Android.mk

+3 −3
Original line number Diff line number Diff line
@@ -50,7 +50,8 @@ commonSources := \ 
	threads.c \

	sched_policy.c \

	iosched_policy.c \

	str_parms.c

	str_parms.c \

	multiuser.c



commonHostSources := \

        ashmem-host.c
@@ -124,8 +125,7 @@ LOCAL_SRC_FILES := $(commonSources) \ 
        mq.c \

        partition_utils.c \

        qtaguid.c \

        uevent.c \

        multiuser.c

        uevent.c



ifeq ($(TARGET_ARCH),arm)

LOCAL_SRC_FILES += arch-arm/memset32.S

libcutils/multiuser.c

+3 −6
Original line number Diff line number Diff line
@@ -14,19 +14,16 @@ 
 * limitations under the License.

 */



#include <stdlib.h>

#include <unistd.h>

#include <fcntl.h>

#include <cutils/multiuser.h>



userid_t getUserId(uid_t uid) {

userid_t multiuser_getUserId(uid_t uid) {

    return uid / MULTIUSER_APP_PER_USER_RANGE;

}



appid_t getAppId(uid_t uid) {

appid_t multiuser_getAppId(uid_t uid) {

    return uid % MULTIUSER_APP_PER_USER_RANGE;

}



uid_t getUid(userid_t userId, appid_t appId) {

uid_t multiuser_getUid(userid_t userId, appid_t appId) {

    return userId * MULTIUSER_APP_PER_USER_RANGE + (appId % MULTIUSER_APP_PER_USER_RANGE);

}