rand_win.c: handle GetTickCount wrap-around.

crypto/rand/rand_win.c

@@ -463,7 +463,7 @@ int RAND_poll(void)
 		PROCESSENTRY32 p;
 		THREADENTRY32 t;
 		MODULEENTRY32 m;
-		DWORD stoptime = 0;
+		DWORD starttime = 0;
 
 		snap = (CREATETOOLHELP32SNAPSHOT)
 			GetProcAddress(kernel, "CreateToolhelp32Snapshot");
@@ -496,7 +496,7 @@ int RAND_poll(void)
                          */
 			ZeroMemory(&hlist, sizeof(HEAPLIST32));
 			hlist.dwSize = sizeof(HEAPLIST32);		
-			if (good) stoptime = GetTickCount() + MAXDELAY;
+			if (good) starttime = GetTickCount();
 #ifdef _MSC_VER
 			if (heaplist_first(handle, &hlist))
 				{
@@ -536,7 +536,7 @@ int RAND_poll(void)
 							ex_cnt_limit--;
 						}
 					} while (heaplist_next(handle, &hlist) 
-						&& GetTickCount() < stoptime 
+						&& (GetTickCount()-starttime)<MAXDELAY
 						&& ex_cnt_limit > 0);
 				}
 
@@ -559,7 +559,7 @@ int RAND_poll(void)
 							&& --entrycnt > 0);
 						}
 					} while (heaplist_next(handle, &hlist) 
-						&& GetTickCount() < stoptime);
+						&& (GetTickCount()-starttime)<MAXDELAY);
 				}
 #endif
 
@@ -570,11 +570,11 @@ int RAND_poll(void)
                          */
 			p.dwSize = sizeof(PROCESSENTRY32);
 		
-			if (good) stoptime = GetTickCount() + MAXDELAY;
+			if (good) starttime = GetTickCount();
 			if (process_first(handle, &p))
 				do
 					RAND_add(&p, p.dwSize, 9);
-				while (process_next(handle, &p) && GetTickCount() < stoptime);
+				while (process_next(handle, &p) && (GetTickCount()-starttime)<MAXDELAY);
 
 			/* thread walking */
                         /* THREADENTRY32 contains 6 fields that will change
@@ -582,11 +582,11 @@ int RAND_poll(void)
                          * 1 byte of entropy.
                          */
 			t.dwSize = sizeof(THREADENTRY32);
-			if (good) stoptime = GetTickCount() + MAXDELAY;
+			if (good) starttime = GetTickCount();
 			if (thread_first(handle, &t))
 				do
 					RAND_add(&t, t.dwSize, 6);
-				while (thread_next(handle, &t) && GetTickCount() < stoptime);
+				while (thread_next(handle, &t) && (GetTickCount()-starttime)<MAXDELAY);
 
 			/* module walking */
                         /* MODULEENTRY32 contains 9 fields that will change
@@ -594,12 +594,12 @@ int RAND_poll(void)
                          * 1 byte of entropy.
                          */
 			m.dwSize = sizeof(MODULEENTRY32);
-			if (good) stoptime = GetTickCount() + MAXDELAY;
+			if (good) starttime = GetTickCount();
 			if (module_first(handle, &m))
 				do
 					RAND_add(&m, m.dwSize, 9);
 				while (module_next(handle, &m)
-					       	&& (GetTickCount() < stoptime));
+					       	&& (GetTickCount()-starttime)<MAXDELAY);
 			if (close_snap)
 				close_snap(handle);
 			else