am 2f169162: Merge "libc: Fix leak in the DNS thread-specific state." into honeycomb-mr1
* commit '2f169162462e44d7aa6443e682b15fc756c2e4ad':
libc: Fix leak in the DNS thread-specific state.
diff --git a/libc/netbsd/resolv/res_init.c b/libc/netbsd/resolv/res_init.c
index 2158f20..ffd4054 100644
--- a/libc/netbsd/resolv/res_init.c
+++ b/libc/netbsd/resolv/res_init.c
@@ -225,6 +225,9 @@
char dnsProperty[PROP_VALUE_MAX];
#endif
+ if ((statp->options & RES_INIT) != 0U)
+ res_ndestroy(statp);
+
if (!preinit) {
statp->retrans = RES_TIMEOUT;
statp->retry = RES_DFLRETRY;
@@ -232,9 +235,6 @@
statp->id = res_randomid();
}
- if ((statp->options & RES_INIT) != 0U)
- res_ndestroy(statp);
-
memset(u, 0, sizeof(u));
#ifdef USELOOPBACK
u[nserv].sin.sin_addr = inet_makeaddr(IN_LOOPBACKNET, 1);
diff --git a/libc/netbsd/resolv/res_state.c b/libc/netbsd/resolv/res_state.c
index 3209b6f..322ace9 100644
--- a/libc/netbsd/resolv/res_state.c
+++ b/libc/netbsd/resolv/res_state.c
@@ -38,21 +38,32 @@
#define _REALLY_INCLUDE_SYS__SYSTEM_PROPERTIES_H_
#include <sys/_system_properties.h>
+/* Set to 1 to enable debug traces */
+#define DEBUG 0
+
+#if DEBUG
+# include <logd.h>
+# include <unistd.h> /* for gettid() */
+# define D(...) __libc_android_log_print(ANDROID_LOG_DEBUG,"libc", __VA_ARGS__)
+#else
+# define D(...) do{}while(0)
+#endif
+
static pthread_key_t _res_key;
static pthread_once_t _res_once;
typedef struct {
- int _h_errno;
- struct __res_state _nres[1];
- unsigned _serial;
- struct prop_info* _pi;
- struct res_static _rstatic[1];
+ int _h_errno;
+ struct __res_state _nres[1];
+ unsigned _serial;
+ struct prop_info* _pi;
+ struct res_static _rstatic[1];
} _res_thread;
static _res_thread*
_res_thread_alloc(void)
{
- _res_thread* rt = malloc(sizeof(*rt));
+ _res_thread* rt = calloc(1, sizeof(*rt));
if (rt) {
rt->_h_errno = 0;
@@ -62,12 +73,7 @@
if (rt->_pi) {
rt->_serial = rt->_pi->serial;
}
- if ( res_ninit( rt->_nres ) < 0 ) {
- free(rt);
- rt = NULL;
- } else {
- memset(rt->_rstatic, 0, sizeof rt->_rstatic);
- }
+ memset(rt->_rstatic, 0, sizeof rt->_rstatic);
}
return rt;
}
@@ -91,6 +97,8 @@
{
_res_thread* rt = _rt;
+ D("%s: rt=%p for thread=%d", __FUNCTION__, rt, gettid());
+
_res_static_done(rt->_rstatic);
res_ndestroy(rt->_nres);
free(rt);
@@ -108,27 +116,59 @@
_res_thread* rt;
pthread_once( &_res_once, _res_init_key );
rt = pthread_getspecific( _res_key );
- if (rt == NULL) {
- if ((rt = _res_thread_alloc()) == NULL) {
- return NULL;
+
+ 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;
+ }
}
- rt->_h_errno = 0;
- rt->_serial = 0;
- pthread_setspecific( _res_key, rt );
+ if (rt->_serial == rt->_pi->serial) {
+ /* 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 = rt->_pi->serial;
+ goto RESET_STATE;
}
- /* Check the serial value for any chanes to net.* properties. */
- if (rt->_pi == NULL) {
- rt->_pi = (struct prop_info*) __system_property_find("net.change");
+
+ /* 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;
}
- if (rt->_pi == NULL || rt->_serial == rt->_pi->serial) {
- return rt;
- }
- rt->_serial = rt->_pi->serial;
- /* Reload from system properties. */
+ 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 ) {
- free(rt);
- rt = NULL;
- pthread_setspecific( _res_key, rt );
+ /* 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;
}
_resolv_cache_reset(rt->_serial);
return rt;