liblog: Add __android_log_security()
Return non-zero if ro.device_owner is set and not false
and persist.logd.security is true.
Bug: 26029733
Change-Id: Ie82ae11ae35e9c79017b6e873fefb39d79a1d4fe
diff --git a/liblog/log_is_loggable.c b/liblog/log_is_loggable.c
index 7fc01d9..854ecfa 100644
--- a/liblog/log_is_loggable.c
+++ b/liblog/log_is_loggable.c
@@ -45,6 +45,9 @@
char c;
};
+#define BOOLEAN_TRUE 0xFF
+#define BOOLEAN_FALSE 0xFE
+
static void refresh_cache(struct cache *cache, const char *key)
{
uint32_t serial;
@@ -62,7 +65,16 @@
}
cache->serial = serial;
__system_property_read(cache->pinfo, 0, buf);
- cache->c = buf[0];
+ 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];
+ }
}
static int __android_log_level(const char *tag, int default_prio)
@@ -147,6 +159,7 @@
case 'F': /* Not officially supported */
case 'A':
case 'S':
+ case BOOLEAN_FALSE: /* Not officially supported */
break;
default:
/* clear '.' after log.tag */
@@ -180,6 +193,7 @@
case 'E': return ANDROID_LOG_ERROR;
case 'F': /* FALLTHRU */ /* Not officially supported */
case 'A': return ANDROID_LOG_FATAL;
+ case BOOLEAN_FALSE: /* FALLTHRU */ /* Not Officially supported */
case 'S': return -1; /* ANDROID_LOG_SUPPRESS */
}
return default_prio;
@@ -226,3 +240,36 @@
return (tolower(c) == 'm') ? CLOCK_MONOTONIC : CLOCK_REALTIME;
}
+
+/*
+ * security state generally remains constant, since a change is
+ * rare, we can accept a trylock failure gracefully.
+ */
+static pthread_mutex_t lock_security = PTHREAD_MUTEX_INITIALIZER;
+
+int __android_log_security()
+{
+ static struct cache r_do_cache = { NULL, -1, BOOLEAN_FALSE };
+ static struct cache p_security_cache = { NULL, -1, BOOLEAN_FALSE };
+ int retval;
+
+ if (pthread_mutex_trylock(&lock_security)) {
+ /* We are willing to accept some race in this context */
+ retval = (r_do_cache.c != BOOLEAN_FALSE) && r_do_cache.c &&
+ (p_security_cache.c == BOOLEAN_TRUE);
+ } else {
+ static uint32_t serial;
+ uint32_t current_serial = __system_property_area_serial();
+ if (current_serial != serial) {
+ refresh_cache(&r_do_cache, "ro.device_owner");
+ refresh_cache(&p_security_cache, "persist.logd.security");
+ serial = current_serial;
+ }
+ retval = (r_do_cache.c != BOOLEAN_FALSE) && r_do_cache.c &&
+ (p_security_cache.c == BOOLEAN_TRUE);
+
+ pthread_mutex_unlock(&lock_security);
+ }
+
+ return retval;
+}