aboutsummaryrefslogtreecommitdiff
path: root/resolv/res_libc.c
diff options
context:
space:
mode:
Diffstat (limited to 'resolv/res_libc.c')
-rw-r--r--resolv/res_libc.c52
1 files changed, 52 insertions, 0 deletions
diff --git a/resolv/res_libc.c b/resolv/res_libc.c
index 94bb2fdca6..b1047f009b 100644
--- a/resolv/res_libc.c
+++ b/resolv/res_libc.c
@@ -15,16 +15,31 @@
* SOFTWARE.
*/
+#include <limits.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <arpa/nameser.h>
#include <resolv.h>
+#include <bits/libc-lock.h>
/* The following bit is copied from res_data.c (where it is #ifdef'ed
out) since res_init() should go into libc.so but the rest of that
file should not. */
+unsigned long long int __res_initstamp attribute_hidden;
+/* We have atomic increment operations on 64-bit platforms. */
+#if __WORDSIZE == 64
+# define atomicinclock(lock) (void) 0
+# define atomicincunlock(lock) (void) 0
+# define atomicinc(var) atomic_increment (&(var))
+#else
+__libc_lock_define_initialized (static, lock);
+# define atomicinclock(lock) __libc_lock_lock (lock)
+# define atomicincunlock(lock) __libc_lock_unlock (lock)
+# define atomicinc(var) ++var
+#endif
+
int
res_init(void) {
extern int __res_vinit(res_state, int);
@@ -70,8 +85,45 @@ res_init(void) {
if (!_res.id)
_res.id = res_randomid();
+ atomicinclock (lock);
+ /* Request all threads to re-initialize their resolver states,
+ resolv.conf might have changed. */
+ atomicinc (__res_initstamp);
+ atomicincunlock (lock);
+
return (__res_vinit(&_res, 1));
}
+
+/* Initialize resp if RES_INIT is not yet set or if res_init in some other
+ thread requested re-initializing. */
+int
+__res_maybe_init (res_state resp, int preinit)
+{
+ if (resp->options & RES_INIT) {
+ if (__res_initstamp != resp->_u._ext.initstamp) {
+ if (resp->nscount > 0) {
+ __res_nclose (resp);
+ for (int ns = 0; ns < MAXNS; ns++) {
+ free (resp->_u._ext.nsaddrs[ns]);
+ resp->_u._ext.nsaddrs[ns] = NULL;
+ }
+ return __res_vinit (resp, 1);
+ }
+ }
+ return 0;
+ } else if (preinit) {
+ if (!resp->retrans)
+ resp->retrans = RES_TIMEOUT;
+ if (!resp->retry)
+ resp->retry = 4;
+ resp->options = RES_DEFAULT;
+ if (!resp->id)
+ resp->id = res_randomid ();
+ return __res_vinit (resp, 1);
+ } else
+ return __res_ninit (resp);
+}
+libc_hidden_def (__res_maybe_init)
/* This needs to be after the use of _res in res_init, above. */
#undef _res