getservbyport_r: fix out-of-bounds buffer read

[musl] / src / thread / vmlock.c

diff --git a/src/thread/vmlock.c b/src/thread/vmlock.c
index 125c6dc..fa0a8e3 100644 (file)
--- a/src/thread/vmlock.c
+++ b/src/thread/vmlock.c
@@ -1,22 +1,23 @@
 #include "pthread_impl.h"
+#include "fork_impl.h"
 
 static volatile int vmlock[2];
+volatile int *const __vmlock_lockptr = vmlock;
 
-void __vm_lock(int inc)
+void __vm_wait()
 {
-       for (;;) {
-               int v = vmlock[0];
-               if (inc*v < 0) __wait(vmlock, vmlock+1, v, 1);
-               else if (a_cas(vmlock, v, v+inc)==v) break;
-       }
+       int tmp;
+       while ((tmp=vmlock[0]))
+               __wait(vmlock, vmlock+1, tmp, 1);
 }
 
-void __vm_unlock(void)
+void __vm_lock()
 {
-       int inc = vmlock[0]>0 ? -1 : 1;
-       if (a_fetch_add(vmlock, inc)==-inc && vmlock[1])
-               __wake(vmlock, -1, 1);
+       a_inc(vmlock);
 }
 
-weak_alias(__vm_lock, __vm_lock_impl);
-weak_alias(__vm_unlock, __vm_unlock_impl);
+void __vm_unlock()
+{
+       if (a_fetch_add(vmlock, -1)==1 && vmlock[1])
+               __wake(vmlock, -1, 1);
+}