static void refresh_cache(struct cache *cache, const char *key)
{
uint32_t serial;
char buf[PROP_VALUE_MAX];
if (!cache->pinfo) {
cache->pinfo = __system_property_find(key);
if (!cache->pinfo) {
return;
}
cache->serial = -1;
}
serial = __system_property_serial(cache->pinfo);
if (serial == cache->serial) {
return;
}
cache->serial = serial;
__system_property_read(cache->pinfo, 0, buf);
switch(buf[0]) {
case 't': case 'T':
cache->c = strcasecmp(buf + 1, "rue") ? buf[0] : BOOLEAN_TRUE;
break;
case 'f': case 'F':
cache->c = strcasecmp(buf + 1, "alse") ? buf[0] : BOOLEAN_FALSE;
break;
default:
cache->c = buf[0];
}
}
int __system_property_read(const prop_info *pi, char *name, char *value)
{
if (__predict_false(compat_mode)) {
return __system_property_read_compat(pi, name, value);
}
while (true) {
uint32_t serial = __system_property_serial(pi); // acquire semantics
size_t len = SERIAL_VALUE_LEN(serial);
memcpy(value, pi->value, len + 1);
// TODO: Fix the synchronization scheme here.
// There is no fully supported way to implement this kind
// of synchronization in C++11, since the memcpy races with
// updates to pi, and the data being accessed is not atomic.
// The following fence is unintuitive, but would be the
// correct one if memcpy used memory_order_relaxed atomic accesses.
// In practice it seems unlikely that the generated code would
// would be any different, so this should be OK.
atomic_thread_fence(memory_order_acquire);
if (serial ==
load_const_atomic(&(pi->serial), memory_order_relaxed)) {
if (name != 0) {
strcpy(name, pi->name);
}
return len;
}
}
}
TEST(properties, serial) {
#if defined(__BIONIC__)
LocalPropertyTestState pa;
ASSERT_TRUE(pa.valid);
const prop_info *pi;
unsigned int serial;
ASSERT_EQ(0, __system_property_add("property", 8, "value1", 6));
ASSERT_NE((const prop_info *)NULL, pi = __system_property_find("property"));
serial = __system_property_serial(pi);
ASSERT_EQ(0, __system_property_update((prop_info *)pi, "value2", 6));
ASSERT_NE(serial, __system_property_serial(pi));
#else // __BIONIC__
GTEST_LOG_(INFO) << "This test does nothing.\n";
#endif // __BIONIC__
}
static void BM_property_serial(int iters, int nprops)
{
StopBenchmarkTiming();
LocalPropertyTestState pa(nprops);
if (!pa.valid)
return;
srandom(iters * nprops);
const prop_info** pinfo = new const prop_info*[iters];
for (int i = 0; i < iters; i++) {
pinfo[i] = __system_property_find(pa.names[random() % nprops]);
}
// StartBenchmarkTiming();
for (int i = 0; i < iters; i++) {
StartBenchmarkTiming();
__system_property_serial(pinfo[i]);
StopBenchmarkTimingWithStd();
}
// StopBenchmarkTiming();
delete[] pinfo;
}
static void refresh_cache_property(struct cache_property* cache, const char* key)
{
if (!cache->cache.pinfo) {
cache->cache.pinfo = __system_property_find(key);
if (!cache->cache.pinfo) {
return;
}
}
cache->cache.serial = __system_property_serial(cache->cache.pinfo);
__system_property_read(cache->cache.pinfo, 0, cache->property);
}
static void print_sys_prop(const struct prop_info *pi, void *cookies)
{
char key[PROP_NAME_MAX];
char name[PROP_VALUE_MAX];
unsigned int serial;
int valuelen;
serial = __system_property_serial(pi);
valuelen = __system_property_read(pi, key, name);
if (valuelen < 1 || valuelen > PROP_VALUE_MAX)
return;
klog_write(6, "<6> [+%3u]%-32s = %s\n",
(serial & 0xffffff) >> 1, key, name);
}
static _res_thread*
_res_thread_alloc(void)
{
_res_thread* rt = calloc(1, sizeof(*rt));
if (rt) {
rt->_h_errno = 0;
/* Special system property which tracks any changes to 'net.*'. */
rt->_serial = 0;
rt->_pi = (struct prop_info*) __system_property_find("net.change");
if (rt->_pi) {
rt->_serial = __system_property_serial(rt->_pi);
}
memset(rt->_rstatic, 0, sizeof rt->_rstatic);
}
return rt;
}
static void refresh_cache(struct cache *cache, const char *key)
{
uint32_t serial;
char buf[PROP_VALUE_MAX];
if (!cache->pinfo) {
cache->pinfo = __system_property_find(key);
if (!cache->pinfo) {
return;
}
}
serial = __system_property_serial(cache->pinfo);
if (serial == cache->serial) {
return;
}
cache->serial = serial;
__system_property_read(cache->pinfo, 0, buf);
cache->c = buf[0];
}
static int check_cache(struct cache *cache)
{
return cache->pinfo
&& __system_property_serial(cache->pinfo) != cache->serial;
}
int wifi_start_supplicant(int p2p_supported)
{
char supp_status[PROPERTY_VALUE_MAX] = {'\0'};
int count = 200; /* wait at most 20 seconds for completion */
#ifdef HAVE_LIBC_SYSTEM_PROPERTIES
const prop_info *pi;
unsigned serial = 0, i;
#endif
if (p2p_supported) {
strcpy(supplicant_name, P2P_SUPPLICANT_NAME);
strcpy(supplicant_prop_name, P2P_PROP_NAME);
/* Ensure p2p config file is created */
if (ensure_config_file_exists(P2P_CONFIG_FILE) < 0) {
ALOGE("Failed to create a p2p config file");
return -1;
}
} else {
strcpy(supplicant_name, SUPPLICANT_NAME);
strcpy(supplicant_prop_name, SUPP_PROP_NAME);
}
/* Check whether already running */
if (property_get(supplicant_prop_name, supp_status, NULL)
&& strcmp(supp_status, "running") == 0) {
return 0;
}
/* Before starting the daemon, make sure its config file exists */
if (ensure_config_file_exists(SUPP_CONFIG_FILE) < 0) {
ALOGE("Wi-Fi will not be enabled");
return -1;
}
if (ensure_entropy_file_exists() < 0) {
ALOGE("Wi-Fi entropy file was not created");
}
/* Clear out any stale socket files that might be left over. */
wpa_ctrl_cleanup();
/* Reset sockets used for exiting from hung state */
exit_sockets[0] = exit_sockets[1] = -1;
#ifdef HAVE_LIBC_SYSTEM_PROPERTIES
/*
* Get a reference to the status property, so we can distinguish
* the case where it goes stopped => running => stopped (i.e.,
* it start up, but fails right away) from the case in which
* it starts in the stopped state and never manages to start
* running at all.
*/
pi = __system_property_find(supplicant_prop_name);
if (pi != NULL) {
serial = __system_property_serial(pi);
}
#endif
property_get("wifi.interface", primary_iface, WIFI_TEST_INTERFACE);
property_set("ctl.start", supplicant_name);
sched_yield();
while (count-- > 0) {
#ifdef HAVE_LIBC_SYSTEM_PROPERTIES
if (pi == NULL) {
pi = __system_property_find(supplicant_prop_name);
}
if (pi != NULL) {
/*
* property serial updated means that init process is scheduled
* after we sched_yield, further property status checking is based on this */
if (__system_property_serial(pi) != serial) {
__system_property_read(pi, NULL, supp_status);
if (strcmp(supp_status, "running") == 0) {
return 0;
} else if (strcmp(supp_status, "stopped") == 0) {
return -1;
}
}
}
#else
if (property_get(supplicant_prop_name, supp_status, NULL)) {
if (strcmp(supp_status, "running") == 0)
return 0;
}
#endif
usleep(100000);
}
return -1;
}
static _res_thread*
_res_thread_get(void)
{
_res_thread* rt;
pthread_once( &_res_once, _res_init_key );
rt = pthread_getspecific( _res_key );
if (rt != NULL) {
/* We already have one thread-specific DNS state object.
* Check the serial value for any changes to net.* properties */
D("%s: Called for tid=%d rt=%p rt->pi=%p rt->serial=%d",
__FUNCTION__, gettid(), rt, rt->_pi, rt->_serial);
if (rt->_pi == NULL) {
/* The property wasn't created when _res_thread_get() was
* called the last time. This should only happen very
* early during the boot sequence. First, let's try to see if it
* is here now. */
rt->_pi = (struct prop_info*) __system_property_find("net.change");
if (rt->_pi == NULL) {
/* Still nothing, return current state */
D("%s: exiting for tid=%d rt=%d since system property not found",
__FUNCTION__, gettid(), rt);
return rt;
}
}
if (rt->_serial == __system_property_serial(rt->_pi)) {
/* Nothing changed, so return the current state */
D("%s: tid=%d rt=%p nothing changed, returning",
__FUNCTION__, gettid(), rt);
return rt;
}
/* Update the recorded serial number, and go reset the state */
rt->_serial = __system_property_serial(rt->_pi);
goto RESET_STATE;
}
/* It is the first time this function is called in this thread,
* we need to create a new thread-specific DNS resolver state. */
rt = _res_thread_alloc();
if (rt == NULL) {
return NULL;
}
pthread_setspecific( _res_key, rt );
D("%s: tid=%d Created new DNS state rt=%p",
__FUNCTION__, gettid(), rt);
RESET_STATE:
/* Reset the state, note that res_ninit() can now properly reset
* an existing state without leaking memory.
*/
D("%s: tid=%d, rt=%p, resetting DNS state (options RES_INIT=%d)",
__FUNCTION__, gettid(), rt, (rt->_nres->options & RES_INIT) != 0);
if ( res_ninit( rt->_nres ) < 0 ) {
/* This should not happen */
D("%s: tid=%d rt=%p, woot, res_ninit() returned < 0",
__FUNCTION__, gettid(), rt);
_res_thread_free(rt);
pthread_setspecific( _res_key, NULL );
return NULL;
}
return rt;
}
