diff --git a/libc/arch-arm/krait/bionic/memcpy.S b/libc/arch-arm/krait/bionic/memcpy.S
index 0cd4d44..4a21709 100644
--- a/libc/arch-arm/krait/bionic/memcpy.S
+++ b/libc/arch-arm/krait/bionic/memcpy.S
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2008 The Android Open Source Project
+ * Copyright (C) 2013 The Android Open Source Project
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -45,9 +45,8 @@
 ENTRY(memcpy)
         .save       {r0, lr}
         /* start preloading as early as possible */
-        pld         [r1, #(CACHE_LINE_SIZE*0)]
+        pld         [r1, #(CACHE_LINE_SIZE*4)]
         stmfd       sp!, {r0, lr}
-        pld         [r1, #(CACHE_LINE_SIZE*2)]
 
         /* do we have at least 16-bytes to copy (needed for alignment below) */
         cmp         r2, #16
@@ -56,7 +55,7 @@
         /* align destination to cache-line for the write-buffer */
         rsb         r3, r0, #0
         ands        r3, r3, #0xF
-        beq         0f
+        beq         2f
 
         /* copy up to 15-bytes (count in r3) */
         sub         r2, r2, r3
@@ -76,47 +75,29 @@
         // copies 8 bytes, destination 64-bits aligned
         vld1.8      {d0}, [r1]!
         vst1.8      {d0}, [r0, :64]!
-2:
 
-0:      /* preload immediately the next cache line, which we may need */
-        pld         [r1, #(CACHE_LINE_SIZE*0)]
-        pld         [r1, #(CACHE_LINE_SIZE*2)]
-
-        /* make sure we have at least 64 bytes to copy */
+2:      /* make sure we have at least 64 bytes to copy */
         subs        r2, r2, #64
         blo         2f
 
-        /* Preload all the cache lines we need.
-         * NOTE: The number of pld below depends on CACHE_LINE_SIZE,
-         * ideally we would increase the distance in the main loop to
-         * avoid the goofy code below. In practice this doesn't seem to make
-         * a big difference.
-         * NOTE: The value CACHE_LINE_SIZE * 8 was chosen through
-         * experimentation.
-         */
-        pld         [r1, #(CACHE_LINE_SIZE*4)]
-        pld         [r1, #(CACHE_LINE_SIZE*6)]
-        pld         [r1, #(CACHE_LINE_SIZE*8)]
-
 1:      /* The main loop copies 64 bytes at a time */
         vld1.8      {d0  - d3},   [r1]!
         vld1.8      {d4  - d7},   [r1]!
-        pld         [r1, #(CACHE_LINE_SIZE*8)]
+        pld         [r1, #(CACHE_LINE_SIZE*2)]
         subs        r2, r2, #64
         vst1.8      {d0  - d3},   [r0, :128]!
         vst1.8      {d4  - d7},   [r0, :128]!
         bhs         1b
 
 2:      /* fix-up the remaining count and make sure we have >= 32 bytes left */
-        add         r2, r2, #64
-        subs        r2, r2, #32
+        adds        r2, r2, #32
         blo         4f
 
-3:      /* 32 bytes at a time. These cache lines were already preloaded */
+        /* Copy 32 bytes. These cache lines were already preloaded */
         vld1.8      {d0 - d3},  [r1]!
-        subs        r2, r2, #32
+        sub         r2, r2, #32
         vst1.8      {d0 - d3},  [r0, :128]!
-        bhs         3b
+
 4:      /* less than 32 left */
         add         r2, r2, #32
         tst         r2, #0x10
diff --git a/libc/bionic/mmap.c b/libc/bionic/mmap.c
index 40a6538..e097086 100644
--- a/libc/bionic/mmap.c
+++ b/libc/bionic/mmap.c
@@ -34,10 +34,17 @@
 #define  MMAP2_SHIFT  12
 void* mmap(void *addr, size_t size, int prot, int flags, int fd, long offset)
 {
+    void *ret;
+
     if (offset & ((1UL << MMAP2_SHIFT)-1)) {
         errno = EINVAL;
         return MAP_FAILED;
     }
 
-    return __mmap2(addr, size, prot, flags, fd, (size_t)offset >> MMAP2_SHIFT);
+    ret = __mmap2(addr, size, prot, flags, fd, (size_t)offset >> MMAP2_SHIFT);
+
+    if (ret && (flags & (MAP_PRIVATE | MAP_ANONYMOUS)))
+	    madvise(ret, size, MADV_MERGEABLE);
+
+    return ret;
 }
diff --git a/libc/bionic/system_properties.c b/libc/bionic/system_properties.c
index 5197ef3..800c8b8 100644
--- a/libc/bionic/system_properties.c
+++ b/libc/bionic/system_properties.c
@@ -55,7 +55,6 @@
     unsigned volatile serial;
     unsigned magic;
     unsigned version;
-    unsigned reserved[4];
     unsigned toc[1];
 };
 
@@ -70,10 +69,9 @@
 typedef struct prop_info prop_info;
 
 static const char property_service_socket[] = "/dev/socket/" PROP_SERVICE_NAME;
+static char property_filename[PATH_MAX] = PROP_FILENAME;
 
-static unsigned dummy_props = 0;
-
-prop_area *__system_property_area__ = (void*) &dummy_props;
+prop_area *__system_property_regions__[PA_REGION_COUNT] = { NULL, };
 
 static int get_fd_from_env(void)
 {
@@ -86,27 +84,79 @@
     return atoi(env);
 }
 
-void __system_property_area_init(void *data)
+static int map_prop_region_rw(size_t region)
 {
-    prop_area *pa = data;
+    prop_area *pa;
+    int fd;
+    size_t offset = region * PA_SIZE;
+
+    if (__system_property_regions__[region]) {
+        return 0;
+    }
+
+    /* dev is a tmpfs that we can use to carve a shared workspace
+     * out of, so let's do that...
+     */
+    fd = open(property_filename, O_RDWR | O_CREAT | O_NOFOLLOW, 0644);
+    if (fd < 0) {
+        if (errno == EACCES) {
+            /* for consistency with the case where the process has already
+             * mapped the page in and segfaults when trying to write to it
+             */
+            abort();
+        }
+        return -1;
+    }
+
+    if (ftruncate(fd, offset + PA_SIZE) < 0)
+        goto out;
+
+    pa = mmap(NULL, PA_SIZE, PROT_READ | PROT_WRITE, MAP_SHARED, fd, offset);
+    if(pa == MAP_FAILED)
+        goto out;
+
     memset(pa, 0, PA_SIZE);
     pa->magic = PROP_AREA_MAGIC;
     pa->version = PROP_AREA_VERSION;
 
     /* plug into the lib property services */
-    __system_property_area__ = pa;
+    __system_property_regions__[region] = pa;
+
+    close(fd);
+    return 0;
+
+out:
+    close(fd);
+    return -1;
 }
 
-int __system_properties_init(void)
+int __system_property_set_filename(const char *filename)
+{
+    size_t len = strlen(filename);
+    if (len >= sizeof(property_filename))
+        return -1;
+
+    strcpy(property_filename, filename);
+    return 0;
+}
+
+int __system_property_area_init()
+{
+    return map_prop_region_rw(0);
+}
+
+static int map_prop_region(size_t region)
 {
     bool fromFile = true;
+    bool swapped;
+    size_t offset = region * PA_SIZE;
     int result = -1;
 
-    if(__system_property_area__ != ((void*) &dummy_props)) {
+    if(__system_property_regions__[region]) {
         return 0;
     }
 
-    int fd = open(PROP_FILENAME, O_RDONLY | O_NOFOLLOW);
+    int fd = open(property_filename, O_RDONLY | O_NOFOLLOW);
 
     if ((fd < 0) && (errno == ENOENT)) {
         /*
@@ -133,23 +183,33 @@
 
     if ((fd_stat.st_uid != 0)
             || (fd_stat.st_gid != 0)
-            || ((fd_stat.st_mode & (S_IWGRP | S_IWOTH)) != 0)) {
+            || ((fd_stat.st_mode & (S_IWGRP | S_IWOTH)) != 0)
+            || (fd_stat.st_size < offset + PA_SIZE) ) {
         goto cleanup;
     }
 
-    prop_area *pa = mmap(NULL, fd_stat.st_size, PROT_READ, MAP_SHARED, fd, 0);
+    prop_area *pa = mmap(NULL, PA_SIZE, PROT_READ, MAP_SHARED, fd, offset);
 
     if (pa == MAP_FAILED) {
         goto cleanup;
     }
 
     if((pa->magic != PROP_AREA_MAGIC) || (pa->version != PROP_AREA_VERSION)) {
-        munmap(pa, fd_stat.st_size);
+        munmap(pa, PA_SIZE);
         goto cleanup;
     }
 
-    __system_property_area__ = pa;
     result = 0;
+    swapped = __sync_bool_compare_and_swap(&__system_property_regions__[region],
+            NULL, pa);
+    if (!swapped) {
+        /**
+         * In the event of a race either mapping is equally good, so
+         * the thread that lost can just throw its mapping away and proceed as
+         * normal.
+         */
+        munmap(pa, PA_SIZE);
+    }
 
 cleanup:
     if (fromFile) {
@@ -159,17 +219,31 @@
     return result;
 }
 
+int __system_properties_init()
+{
+    return map_prop_region(0);
+}
+
 int __system_property_foreach(
         void (*propfn)(const prop_info *pi, void *cookie),
         void *cookie)
 {
-    prop_area *pa = __system_property_area__;
-    unsigned i;
+    size_t region;
 
-    for (i = 0; i < pa->count; i++) {
-        unsigned entry = pa->toc[i];
-        prop_info *pi = TOC_TO_INFO(pa, entry);
-        propfn(pi, cookie);
+    for (region = 0; region < PA_REGION_COUNT; region++) {
+        prop_area *pa;
+        unsigned i;
+
+        int err = map_prop_region(region);
+        if (err < 0)
+            break;
+        pa = __system_property_regions__[region];
+
+        for (i = 0; i < pa->count; i++) {
+            unsigned entry = pa->toc[i];
+            prop_info *pi = TOC_TO_INFO(pa, entry);
+            propfn(pi, cookie);
+        }
     }
 
     return 0;
@@ -177,9 +251,15 @@
 
 const prop_info *__system_property_find_nth(unsigned n)
 {
-    prop_area *pa = __system_property_area__;
+    size_t region = n / PA_COUNT_MAX;
+    prop_area *pa;
 
-    if(n >= pa->count) {
+    int err = map_prop_region(region);
+    if (err < 0)
+        return NULL;
+    pa = __system_property_regions__[region];
+
+    if((n % PA_COUNT_MAX) >= pa->count) {
         return 0;
     } else {
         return TOC_TO_INFO(pa, pa->toc[n]);
@@ -188,25 +268,36 @@
 
 const prop_info *__system_property_find(const char *name)
 {
-    prop_area *pa = __system_property_area__;
-    unsigned count = pa->count;
-    unsigned *toc = pa->toc;
     unsigned len = strlen(name);
-    prop_info *pi;
+    size_t region;
 
     if (len >= PROP_NAME_MAX)
         return 0;
     if (len < 1)
         return 0;
 
-    while(count--) {
-        unsigned entry = *toc++;
-        if(TOC_NAME_LEN(entry) != len) continue;
+    for (region = 0; region < PA_REGION_COUNT; region++) {
+        prop_area *pa;
+        unsigned count;
+        unsigned *toc;
+        prop_info *pi;
 
-        pi = TOC_TO_INFO(pa, entry);
-        if(memcmp(name, pi->name, len)) continue;
+        int err = map_prop_region(region);
+        if (err < 0)
+            return 0;
+        pa = __system_property_regions__[region];
+        count = pa->count;
+        toc = pa->toc;
 
-        return pi;
+        while(count--) {
+            unsigned entry = *toc++;
+            if(TOC_NAME_LEN(entry) != len) continue;
+
+            pi = TOC_TO_INFO(pa, entry);
+            if(memcmp(name, pi->name, len)) continue;
+
+            return pi;
+        }
     }
 
     return 0;
@@ -333,7 +424,7 @@
 {
     unsigned n;
     if(pi == 0) {
-        prop_area *pa = __system_property_area__;
+        prop_area *pa = __system_property_regions__[0];
         n = pa->serial;
         do {
             __futex_wait(&pa->serial, n, 0);
@@ -349,7 +440,7 @@
 
 int __system_property_update(prop_info *pi, const char *value, unsigned int len)
 {
-    prop_area *pa = __system_property_area__;
+    prop_area *pa = __system_property_regions__[0];
 
     if (len >= PROP_VALUE_MAX)
         return -1;
@@ -368,12 +459,11 @@
 int __system_property_add(const char *name, unsigned int namelen,
             const char *value, unsigned int valuelen)
 {
-    prop_area *pa = __system_property_area__;
-    prop_info *pa_info_array = (void*) (((char*) pa) + PA_INFO_START);
+    prop_area *pa;
+    prop_info *pa_info_array;
     prop_info *pi;
+    size_t region;
 
-    if (pa->count == PA_COUNT_MAX)
-        return -1;
     if (namelen >= PROP_NAME_MAX)
         return -1;
     if (valuelen >= PROP_VALUE_MAX)
@@ -381,13 +471,28 @@
     if (namelen < 1)
         return -1;
 
+    for (region = 0; region < PA_REGION_COUNT; region++)
+    {
+        int err = map_prop_region_rw(region);
+        if (err < 0)
+            return -1;
+
+        pa = __system_property_regions__[region];
+
+        if (pa->count < PA_COUNT_MAX)
+            break;
+    }
+
+    if (region == PA_REGION_COUNT)
+        return -1;
+
+    pa_info_array = (void*) (((char*) pa) + PA_INFO_START);
     pi = pa_info_array + pa->count;
     pi->serial = (valuelen << 24);
     memcpy(pi->name, name, namelen + 1);
     memcpy(pi->value, value, valuelen + 1);
 
-    pa->toc[pa->count] =
-        (namelen << 24) | (((unsigned) pi) - ((unsigned) pa));
+    pa->toc[pa->count] = (namelen << 24) | (((unsigned) pi) - ((unsigned) pa));
 
     pa->count++;
     pa->serial++;
@@ -403,7 +508,7 @@
 
 unsigned int __system_property_wait_any(unsigned int serial)
 {
-    prop_area *pa = __system_property_area__;
+    prop_area *pa = __system_property_regions__[0];
 
     do {
         __futex_wait(&pa->serial, serial, 0);
diff --git a/libc/include/sys/_system_properties.h b/libc/include/sys/_system_properties.h
index c5bc223..4971a4c 100644
--- a/libc/include/sys/_system_properties.h
+++ b/libc/include/sys/_system_properties.h
@@ -42,12 +42,13 @@
 #define PROP_SERVICE_NAME "property_service"
 #define PROP_FILENAME "/dev/__properties__"
 
-/* (8 header words + 247 toc words) = 1020 bytes */
-/* 1024 bytes header and toc + 247 prop_infos @ 128 bytes = 32640 bytes */
+/* (4 header words + 28 toc words) = 128 bytes */
+/* 128 bytes header and toc + 28 prop_infos @ 128 bytes = 3712 bytes */
 
-#define PA_COUNT_MAX  247
-#define PA_INFO_START 1024
-#define PA_SIZE       32768
+#define PA_COUNT_MAX    28
+#define PA_REGION_COUNT 128
+#define PA_INFO_START   128
+#define PA_SIZE         4096
 
 #define TOC_NAME_LEN(toc)       ((toc) >> 24)
 #define TOC_TO_INFO(area, toc)  ((prop_info*) (((char*) area) + ((toc) & 0xFFFFFF)))
@@ -97,11 +98,17 @@
 #define PROP_PATH_FACTORY          "/factory/factory.prop"
 
 /*
+** Map the property area from the specified filename.  This
+** method is for testing only.
+*/
+int __system_property_set_filename(const char *filename);
+
+/*
 ** Initialize the area to be used to store properties.  Can
 ** only be done by a single process that has write access to
 ** the property area.
 */
-void __system_property_area_init(void *data);
+int __system_property_area_init();
 
 /* Add a new system property.  Can only be done by a single
 ** process that has write access to the property area, and
diff --git a/libc/netbsd/resolv/res_cache.c b/libc/netbsd/resolv/res_cache.c
index 829bf10..8e1bd14 100644
--- a/libc/netbsd/resolv/res_cache.c
+++ b/libc/netbsd/resolv/res_cache.c
@@ -1258,6 +1258,12 @@
     char                            ifname[IF_NAMESIZE + 1];
     struct resolv_pidiface_info*    next;
 } PidIfaceInfo;
+typedef struct resolv_uidiface_info {
+    int                             uid_start;
+    int                             uid_end;
+    char                            ifname[IF_NAMESIZE + 1];
+    struct resolv_uidiface_info*    next;
+} UidIfaceInfo;
 
 #define  HTABLE_VALID(x)  ((x) != NULL && (x) != HTABLE_DELETED)
 
@@ -1796,6 +1802,9 @@
 // List of pid iface pairs
 static struct resolv_pidiface_info _res_pidiface_list;
 
+// List of uid iface pairs
+static struct resolv_uidiface_info _res_uidiface_list;
+
 // name of the current default inteface
 static char            _res_default_ifname[IF_NAMESIZE + 1];
 
@@ -1805,6 +1814,9 @@
 // lock protecting the _res_pid_iface_list
 static pthread_mutex_t _res_pidiface_list_lock;
 
+// lock protecting the _res_uidiface_list
+static pthread_mutex_t _res_uidiface_list_lock;
+
 /* lookup the default interface name */
 static char *_get_default_iface_locked();
 /* find the first cache that has an associated interface and return the name of the interface */
@@ -1833,12 +1845,19 @@
 /* return 1 if the provided list of name servers differs from the list of name servers
  * currently attached to the provided cache_info */
 static int _resolv_is_nameservers_equal_locked(struct resolv_cache_info* cache_info,
-        char** servers, int numservers);
+        const char** servers, int numservers);
 /* remove a resolv_pidiface_info structure from _res_pidiface_list */
 static void _remove_pidiface_info_locked(int pid);
 /* get a resolv_pidiface_info structure from _res_pidiface_list with a certain pid */
 static struct resolv_pidiface_info* _get_pid_iface_info_locked(int pid);
 
+/* remove a resolv_pidiface_info structure from _res_uidiface_list */
+static int _remove_uidiface_info_locked(int uid_start, int uid_end);
+/* check if a range [low,high] overlaps with any already existing ranges in the uid=>iface map*/
+static int  _resolv_check_uid_range_overlap_locked(int uid_start, int uid_end);
+/* get a resolv_uidiface_info structure from _res_uidiface_list with a certain uid */
+static struct resolv_uidiface_info* _get_uid_iface_info_locked(int uid);
+
 static void
 _res_cache_init(void)
 {
@@ -1852,8 +1871,10 @@
     memset(&_res_default_ifname, 0, sizeof(_res_default_ifname));
     memset(&_res_cache_list, 0, sizeof(_res_cache_list));
     memset(&_res_pidiface_list, 0, sizeof(_res_pidiface_list));
+    memset(&_res_uidiface_list, 0, sizeof(_res_uidiface_list));
     pthread_mutex_init(&_res_cache_list_lock, NULL);
     pthread_mutex_init(&_res_pidiface_list_lock, NULL);
+    pthread_mutex_init(&_res_uidiface_list_lock, NULL);
 }
 
 struct resolv_cache*
@@ -2076,7 +2097,7 @@
 }
 
 void
-_resolv_set_nameservers_for_iface(const char* ifname, char** servers, int numservers,
+_resolv_set_nameservers_for_iface(const char* ifname, const char** servers, int numservers,
         const char *domains)
 {
     int i, rt, index;
@@ -2149,7 +2170,7 @@
 
 static int
 _resolv_is_nameservers_equal_locked(struct resolv_cache_info* cache_info,
-        char** servers, int numservers)
+        const char** servers, int numservers)
 {
     int i;
     char** ns;
@@ -2271,8 +2292,8 @@
         memcpy(&cache_info->ifaddr, addr, sizeof(*addr));
 
         if (DEBUG) {
-            char* addr_s = inet_ntoa(cache_info->ifaddr);
-            XLOG("address of interface %s is %s\n", ifname, addr_s);
+            XLOG("address of interface %s is %s\n",
+                    ifname, inet_ntoa(cache_info->ifaddr));
         }
     }
     pthread_mutex_unlock(&_res_cache_list_lock);
@@ -2411,26 +2432,183 @@
     return len;
 }
 
-int
-_resolv_get_default_iface(char* buff, int buffLen)
+static int
+_remove_uidiface_info_locked(int uid_start, int uid_end) {
+    struct resolv_uidiface_info* result = _res_uidiface_list.next;
+    struct resolv_uidiface_info* prev = &_res_uidiface_list;
+
+    while (result != NULL && result->uid_start != uid_start && result->uid_end != uid_end) {
+        prev = result;
+        result = result->next;
+    }
+    if (prev != NULL && result != NULL) {
+        prev->next = result->next;
+        free(result);
+        return 0;
+    }
+    errno = EINVAL;
+    return -1;
+}
+
+static struct resolv_uidiface_info*
+_get_uid_iface_info_locked(int uid)
 {
-    char* ifname;
+    struct resolv_uidiface_info* result = _res_uidiface_list.next;
+    while (result != NULL && !(result->uid_start <= uid && result->uid_end >= uid)) {
+        result = result->next;
+    }
+
+    return result;
+}
+
+static int
+_resolv_check_uid_range_overlap_locked(int uid_start, int uid_end)
+{
+    struct resolv_uidiface_info* cur = _res_uidiface_list.next;
+    while (cur != NULL) {
+        if (cur->uid_start <= uid_end && cur->uid_end >= uid_start) {
+            return -1;
+        }
+        cur = cur->next;
+    }
+    return 0;
+}
+
+void
+_resolv_clear_iface_uid_range_mapping()
+{
+    pthread_once(&_res_cache_once, _res_cache_init);
+    pthread_mutex_lock(&_res_uidiface_list_lock);
+    struct resolv_uidiface_info *current = _res_uidiface_list.next;
+    struct resolv_uidiface_info *next;
+    while (current != NULL) {
+        next = current->next;
+        free(current);
+        current = next;
+    }
+    _res_uidiface_list.next = NULL;
+    pthread_mutex_unlock(&_res_uidiface_list_lock);
+}
+
+void
+_resolv_clear_iface_pid_mapping()
+{
+    pthread_once(&_res_cache_once, _res_cache_init);
+    pthread_mutex_lock(&_res_pidiface_list_lock);
+    struct resolv_pidiface_info *current = _res_pidiface_list.next;
+    struct resolv_pidiface_info *next;
+    while (current != NULL) {
+        next = current->next;
+        free(current);
+        current = next;
+    }
+    _res_pidiface_list.next = NULL;
+    pthread_mutex_unlock(&_res_pidiface_list_lock);
+}
+
+int
+_resolv_set_iface_for_uid_range(const char* ifname, int uid_start, int uid_end)
+{
+    int rv = 0;
+    struct resolv_uidiface_info* uidiface_info;
+    // make sure the uid iface list is created
+    pthread_once(&_res_cache_once, _res_cache_init);
+    if (uid_start > uid_end) {
+        errno = EINVAL;
+        return -1;
+    }
+    pthread_mutex_lock(&_res_uidiface_list_lock);
+    //check that we aren't adding an overlapping range
+    if (!_resolv_check_uid_range_overlap_locked(uid_start, uid_end)) {
+        uidiface_info = calloc(sizeof(*uidiface_info), 1);
+        if (uidiface_info) {
+            uidiface_info->uid_start = uid_start;
+            uidiface_info->uid_end = uid_end;
+            int len = sizeof(uidiface_info->ifname);
+            strncpy(uidiface_info->ifname, ifname, len - 1);
+            uidiface_info->ifname[len - 1] = '\0';
+
+            uidiface_info->next = _res_uidiface_list.next;
+            _res_uidiface_list.next = uidiface_info;
+
+            XLOG("_resolv_set_iface_for_uid_range: [%d,%d], iface %s\n", low, high, ifname);
+        } else {
+            XLOG("_resolv_set_iface_for_uid_range failing calloc\n");
+            rv = -1;
+            errno = EINVAL;
+        }
+    } else {
+        XLOG("_resolv_set_iface_for_uid_range range [%d,%d] overlaps\n", low, high);
+        rv = -1;
+        errno = EINVAL;
+    }
+
+    pthread_mutex_unlock(&_res_uidiface_list_lock);
+    return rv;
+}
+
+int
+_resolv_clear_iface_for_uid_range(int uid_start, int uid_end)
+{
+    pthread_once(&_res_cache_once, _res_cache_init);
+    pthread_mutex_lock(&_res_uidiface_list_lock);
+
+    int rv = _remove_uidiface_info_locked(uid_start, uid_end);
+
+    XLOG("_resolv_clear_iface_for_uid_range: [%d,%d]\n", uid_start, uid_end);
+
+    pthread_mutex_unlock(&_res_uidiface_list_lock);
+
+    return rv;
+}
+
+int
+_resolv_get_uids_associated_interface(int uid, char* buff, int buffLen)
+{
     int len = 0;
 
-    if (!buff || buffLen == 0) {
+    if (!buff) {
         return -1;
     }
 
     pthread_once(&_res_cache_once, _res_cache_init);
+    pthread_mutex_lock(&_res_uidiface_list_lock);
+
+    struct resolv_uidiface_info* uidiface_info = _get_uid_iface_info_locked(uid);
+    buff[0] = '\0';
+    if (uidiface_info) {
+        len = strlen(uidiface_info->ifname);
+        if (len < buffLen) {
+            strncpy(buff, uidiface_info->ifname, len);
+            buff[len] = '\0';
+        }
+    }
+
+    XLOG("_resolv_get_uids_associated_interface buff: %s\n", buff);
+
+    pthread_mutex_unlock(&_res_uidiface_list_lock);
+
+    return len;
+}
+
+size_t
+_resolv_get_default_iface(char* buff, size_t buffLen)
+{
+    if (!buff || buffLen == 0) {
+        return 0;
+    }
+
+    pthread_once(&_res_cache_once, _res_cache_init);
     pthread_mutex_lock(&_res_cache_list_lock);
 
-    ifname = _get_default_iface_locked(); // never null, but may be empty
+    char* ifname = _get_default_iface_locked(); // never null, but may be empty
 
     // if default interface not set. Get first cache with an interface
     if (ifname[0] == '\0') {
         ifname = _find_any_iface_name_locked(); // may be null
     }
 
+    size_t len = 0;
     // if we got the default iface or if (no-default) the find_any call gave an answer
     if (ifname) {
         len = strlen(ifname);
@@ -2447,28 +2625,32 @@
     return len;
 }
 
-int
+void
 _resolv_populate_res_for_iface(res_state statp)
 {
-    int nserv;
-    struct resolv_cache_info* info = NULL;
+    if (statp == NULL) {
+        return;
+    }
 
-    if (statp) {
+    if (statp->iface[0] == '\0') { // no interface set assign default
+        size_t if_len = _resolv_get_default_iface(statp->iface, sizeof(statp->iface));
+        if (if_len + 1 > sizeof(statp->iface)) {
+            XLOG("%s: INTERNAL_ERROR: can't fit interface name into statp->iface.\n", __FUNCTION__);
+            return;
+        }
+        if (if_len == 0) {
+            XLOG("%s: INTERNAL_ERROR: can't find any suitable interfaces.\n", __FUNCTION__);
+            return;
+        }
+    }
+
+    pthread_once(&_res_cache_once, _res_cache_init);
+    pthread_mutex_lock(&_res_cache_list_lock);
+
+    struct resolv_cache_info* info = _find_cache_info_locked(statp->iface);
+    if (info != NULL) {
+        int nserv;
         struct addrinfo* ai;
-
-        if (statp->iface[0] == '\0') { // no interface set assign default
-            _resolv_get_default_iface(statp->iface, sizeof(statp->iface));
-        }
-
-        pthread_once(&_res_cache_once, _res_cache_init);
-        pthread_mutex_lock(&_res_cache_list_lock);
-        info = _find_cache_info_locked(statp->iface);
-
-        if (info == NULL) {
-            pthread_mutex_unlock(&_res_cache_list_lock);
-            return 0;
-        }
-
         XLOG("_resolv_populate_res_for_iface: %s\n", statp->iface);
         for (nserv = 0; nserv < MAXNS; nserv++) {
             ai = info->nsaddrinfo[nserv];
@@ -2502,8 +2684,6 @@
         while (pp < statp->dnsrch + MAXDNSRCH && *p != -1) {
             *pp++ = &statp->defdname + *p++;
         }
-
-        pthread_mutex_unlock(&_res_cache_list_lock);
     }
-    return nserv;
+    pthread_mutex_unlock(&_res_cache_list_lock);
 }
diff --git a/libc/private/resolv_cache.h b/libc/private/resolv_cache.h
index d70857d..68a1180 100644
--- a/libc/private/resolv_cache.h
+++ b/libc/private/resolv_cache.h
@@ -28,6 +28,7 @@
 #ifndef _RESOLV_CACHE_H_
 #define _RESOLV_CACHE_H_
 
+#include <stddef.h>
 #include <sys/cdefs.h>
 
 struct __res_state;
@@ -77,16 +78,17 @@
 __LIBC_HIDDEN__
 extern struct in_addr* _resolv_get_addr_of_iface(const char* ifname);
 
-/* Copy the name of the default interface to provided buffer.
- * Return length of buffer on success on failure -1 is returned */
+/* Copy the name of the default interface to the provided buffer.
+ * Returns the string length of the default interface,
+ * be that less or more than the buffLen, or 0 if nothing had been written */
 __LIBC_HIDDEN__
-extern int _resolv_get_default_iface(char* buff, int buffLen);
+ extern size_t _resolv_get_default_iface(char* buff, size_t buffLen);
 
 /* sets the name server addresses to the provided res_state structure. The
  * name servers are retrieved from the cache which is associated
  * with the interface to which the res_state structure is associated */
 __LIBC_HIDDEN__
-extern int _resolv_populate_res_for_iface(struct __res_state* statp);
+extern void _resolv_populate_res_for_iface(struct __res_state* statp);
 
 typedef enum {
     RESOLV_CACHE_UNSUPPORTED,  /* the cache can't handle that kind of queries */
diff --git a/libc/private/resolv_iface.h b/libc/private/resolv_iface.h
index bf5abad..ad42793 100644
--- a/libc/private/resolv_iface.h
+++ b/libc/private/resolv_iface.h
@@ -48,7 +48,7 @@
 extern void _resolv_set_default_iface(const char* ifname);
 
 /* set name servers for an interface */
-extern void _resolv_set_nameservers_for_iface(const char* ifname, char** servers, int numservers,
+extern void _resolv_set_nameservers_for_iface(const char* ifname, const char** servers, int numservers,
         const char *domains);
 
 /* tell resolver of the address of an interface */
@@ -66,6 +66,9 @@
 /* clear pid from being associated with an interface */
 extern void _resolv_clear_iface_for_pid(int pid);
 
+/* clear the entire mapping of pids to interfaces. */
+extern void _resolv_clear_iface_pid_mapping();
+
 /** Gets the name of the interface to which the pid is attached.
  *  On error, -1 is returned.
  *  If no interface is found, 0 is returned and buff is set to empty ('\0').
@@ -75,6 +78,27 @@
  *               buffLen Length of buff. An interface is at most IF_NAMESIZE in length */
 extern int _resolv_get_pids_associated_interface(int pid, char* buff, int buffLen);
 
+
+/** set a uid range to use the name servers of the specified interface
+ *  If [low,high] overlaps with an already existing rule -1 is returned */
+extern int _resolv_set_iface_for_uid_range(const char* ifname, int uid_start, int uid_end);
+
+/* clear a uid range from being associated with an interface
+ * If the range given is not mapped -1 is returned. */
+extern int _resolv_clear_iface_for_uid_range(int uid_start, int uid_end);
+
+/* clear the entire mapping of uid ranges to interfaces. */
+extern void _resolv_clear_iface_uid_range_mapping();
+
+/** Gets the name of the interface to which the uid is attached.
+ *  On error, -1 is returned.
+ *  If no interface is found, 0 is returned and buff is set to empty ('\0').
+ *  If an interface is found, the name is copied to buff and the length of the name is returned.
+ *  Arguments:   uid The uid to find an interface for
+ *               buff A buffer to copy the result to
+ *               buffLen Length of buff. An interface is at most IF_NAMESIZE in length */
+extern int _resolv_get_uids_associated_interface(int uid, char* buff, int buffLen);
+
 #endif /* _BIONIC_RESOLV_IFACE_FUNCTIONS_DECLARED */
 
 __END_DECLS
diff --git a/tests/property_benchmark.cpp b/tests/property_benchmark.cpp
index 2c8e2a1..7266bd0 100644
--- a/tests/property_benchmark.cpp
+++ b/tests/property_benchmark.cpp
@@ -15,23 +15,40 @@
  */
 
 #include "benchmark.h"
+#include <unistd.h>
 
 #define _REALLY_INCLUDE_SYS__SYSTEM_PROPERTIES_H_
 #include <sys/_system_properties.h>
 
 #include <vector>
+#include <string>
 
-extern void *__system_property_area__;
+extern void *__system_property_regions__[PA_REGION_COUNT];
 
 #define TEST_NUM_PROPS \
-    Arg(1)->Arg(4)->Arg(16)->Arg(64)->Arg(128)->Arg(247)
+    Arg(1)->Arg(4)->Arg(16)->Arg(64)->Arg(128)->Arg(256)->Arg(512)->Arg(1024)
 
 struct LocalPropertyTestState {
-    LocalPropertyTestState(int nprops) : nprops(nprops) {
+    LocalPropertyTestState(int nprops) : nprops(nprops), valid(false) {
         static const char prop_name_chars[] = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ.-_";
-        old_pa = __system_property_area__;
-        pa = malloc(PA_SIZE);
-        __system_property_area_init(pa);
+
+        char dir_template[] = "/data/nativetest/prop-XXXXXX";
+        char *dirname = mkdtemp(dir_template);
+        if (!dirname) {
+            perror("making temp file for test state failed (is /data/nativetest writable?)");
+            return;
+        }
+
+        for (size_t i = 0; i < PA_REGION_COUNT; i++) {
+            old_pa[i] = __system_property_regions__[i];
+            __system_property_regions__[i] = NULL;
+        }
+
+        pa_dirname = dirname;
+        pa_filename = pa_dirname + "/__properties__";
+
+        __system_property_set_filename(pa_filename.c_str());
+        __system_property_area_init();
 
         names = new char* [nprops];
         name_lens = new int[nprops];
@@ -54,10 +71,22 @@
             }
             __system_property_add(names[i], name_lens[i], values[i], value_lens[i]);
         }
+
+        valid = true;
     }
 
     ~LocalPropertyTestState() {
-        __system_property_area__ = old_pa;
+        if (!valid)
+            return;
+
+        for (size_t i = 0; i < PA_REGION_COUNT; i++) {
+            __system_property_regions__[i] = old_pa[i];
+        }
+
+        __system_property_set_filename(PROP_FILENAME);
+        unlink(pa_filename.c_str());
+        rmdir(pa_dirname.c_str());
+
         for (int i = 0; i < nprops; i++) {
             delete names[i];
             delete values[i];
@@ -66,7 +95,6 @@
         delete[] name_lens;
         delete[] values;
         delete[] value_lens;
-        free(pa);
     }
 public:
     const int nprops;
@@ -74,10 +102,12 @@
     int *name_lens;
     char **values;
     int *value_lens;
+    bool valid;
 
 private:
-    void *pa;
-    void *old_pa;
+    std::string pa_dirname;
+    std::string pa_filename;
+    void *old_pa[PA_REGION_COUNT];
 };
 
 static void BM_property_get(int iters, int nprops)
@@ -87,6 +117,9 @@
     LocalPropertyTestState pa(nprops);
     char value[PROP_VALUE_MAX];
 
+    if (!pa.valid)
+        return;
+
     srandom(iters * nprops);
 
     StartBenchmarkTiming();
@@ -104,6 +137,9 @@
 
     LocalPropertyTestState pa(nprops);
 
+    if (!pa.valid)
+        return;
+
     srandom(iters * nprops);
 
     StartBenchmarkTiming();
diff --git a/tests/system_properties_test.cpp b/tests/system_properties_test.cpp
index 70ff1d6..50bdfdf 100644
--- a/tests/system_properties_test.cpp
+++ b/tests/system_properties_test.cpp
@@ -16,32 +16,61 @@
 
 #include <gtest/gtest.h>
 #include <sys/wait.h>
+#include <unistd.h>
+#include <string>
 
 #if __BIONIC__
 
 #define _REALLY_INCLUDE_SYS__SYSTEM_PROPERTIES_H_
 #include <sys/_system_properties.h>
 
-extern void *__system_property_area__;
+extern void *__system_property_regions__[PA_REGION_COUNT];
 
 struct LocalPropertyTestState {
-    LocalPropertyTestState() {
-        old_pa = __system_property_area__;
-        pa = malloc(PA_SIZE);
-        __system_property_area_init(pa);
+    LocalPropertyTestState() : valid(false) {
+        char dir_template[] = "/data/nativetest/prop-XXXXXX";
+        char *dirname = mkdtemp(dir_template);
+        if (!dirname) {
+            perror("making temp file for test state failed (is /data/nativetest writable?)");
+            return;
+        }
+
+        for (size_t i = 0; i < PA_REGION_COUNT; i++) {
+            old_pa[i] = __system_property_regions__[i];
+            __system_property_regions__[i] = NULL;
+        }
+
+        pa_dirname = dirname;
+        pa_filename = pa_dirname + "/__properties__";
+
+        __system_property_set_filename(pa_filename.c_str());
+        __system_property_area_init();
+        valid = true;
     }
 
     ~LocalPropertyTestState() {
-        __system_property_area__ = old_pa;
-        free(pa);
+        if (!valid)
+            return;
+
+        for (size_t i = 0; i < PA_REGION_COUNT; i++) {
+            __system_property_regions__[i] = old_pa[i];
+        }
+
+        __system_property_set_filename(PROP_FILENAME);
+        unlink(pa_filename.c_str());
+        rmdir(pa_dirname.c_str());
     }
+public:
+    bool valid;
 private:
-    void *pa;
-    void *old_pa;
+    std::string pa_dirname;
+    std::string pa_filename;
+    void *old_pa[PA_REGION_COUNT];
 };
 
 TEST(properties, add) {
     LocalPropertyTestState pa;
+    ASSERT_TRUE(pa.valid);
 
     char propvalue[PROP_VALUE_MAX];
 
@@ -61,6 +90,7 @@
 
 TEST(properties, update) {
     LocalPropertyTestState pa;
+    ASSERT_TRUE(pa.valid);
 
     char propvalue[PROP_VALUE_MAX];
     prop_info *pi;
@@ -91,27 +121,34 @@
     ASSERT_STREQ(propvalue, "value6");
 }
 
-// 247 = max # of properties supported by current implementation
-// (this should never go down)
-TEST(properties, fill_247) {
+TEST(properties, fill) {
     LocalPropertyTestState pa;
+    ASSERT_TRUE(pa.valid);
     char prop_name[PROP_NAME_MAX];
     char prop_value[PROP_VALUE_MAX];
     char prop_value_ret[PROP_VALUE_MAX];
+    int count = 0;
     int ret;
 
-    for (int i = 0; i < 247; i++) {
-        ret = snprintf(prop_name, PROP_NAME_MAX - 1, "property_%d", i);
+    while (true) {
+        ret = snprintf(prop_name, PROP_NAME_MAX - 1, "property_%d", count);
         memset(prop_name + ret, 'a', PROP_NAME_MAX - 1 - ret);
-        ret = snprintf(prop_value, PROP_VALUE_MAX - 1, "value_%d", i);
+        ret = snprintf(prop_value, PROP_VALUE_MAX - 1, "value_%d", count);
         memset(prop_value + ret, 'b', PROP_VALUE_MAX - 1 - ret);
         prop_name[PROP_NAME_MAX - 1] = 0;
         prop_value[PROP_VALUE_MAX - 1] = 0;
 
-        ASSERT_EQ(0, __system_property_add(prop_name, PROP_NAME_MAX - 1, prop_value, PROP_VALUE_MAX - 1));
+        ret = __system_property_add(prop_name, PROP_NAME_MAX - 1, prop_value, PROP_VALUE_MAX - 1);
+        if (ret < 0)
+            break;
+
+        count++;
     }
 
-    for (int i = 0; i < 247; i++) {
+    // For historical reasons at least 247 properties must be supported
+    ASSERT_GE(count, 247);
+
+    for (int i = 0; i < count; i++) {
         ret = snprintf(prop_name, PROP_NAME_MAX - 1, "property_%d", i);
         memset(prop_name + ret, 'a', PROP_NAME_MAX - 1 - ret);
         ret = snprintf(prop_value, PROP_VALUE_MAX - 1, "value_%d", i);
@@ -134,6 +171,7 @@
 
 TEST(properties, foreach) {
     LocalPropertyTestState pa;
+    ASSERT_TRUE(pa.valid);
     size_t count = 0;
 
     ASSERT_EQ(0, __system_property_add("property", 8, "value1", 6));
@@ -146,6 +184,7 @@
 
 TEST(properties, find_nth) {
     LocalPropertyTestState pa;
+    ASSERT_TRUE(pa.valid);
 
     ASSERT_EQ(0, __system_property_add("property", 8, "value1", 6));
     ASSERT_EQ(0, __system_property_add("other_property", 14, "value2", 6));
@@ -165,6 +204,7 @@
 
 TEST(properties, errors) {
     LocalPropertyTestState pa;
+    ASSERT_TRUE(pa.valid);
     char prop_value[PROP_NAME_MAX];
 
     ASSERT_EQ(0, __system_property_add("property", 8, "value1", 6));
@@ -181,6 +221,7 @@
 
 TEST(properties, serial) {
     LocalPropertyTestState pa;
+    ASSERT_TRUE(pa.valid);
     const prop_info *pi;
     unsigned int serial;
 
@@ -206,6 +247,7 @@
 
 TEST(properties, wait) {
     LocalPropertyTestState pa;
+    ASSERT_TRUE(pa.valid);
     unsigned int serial;
     prop_info *pi;
     pthread_t t;