kill05: fix race condition in do_master_child

There is a race condition when starting child. Master child can go forward before child changes its reuid.
Fix this by waiting until child is ready.

---
 testcases/kernel/syscalls/kill/kill05.c |   25 +++++++++++++++++--------
 1 files changed, 17 insertions(+), 8 deletions(-)

index e44b690..fe34788 100644
@@ -130,6 +130,16 @@ int main(int ac, char **av)
 	tst_exit();
 }
 
+void wait_for_flag(int value)
+{
+	while (1) {
+		if (*flag == value)
+			break;
+		else
+			sleep(1);
+	}
+}
+
 /*
  * do_master_child()
  */

@@ -160,6 +170,7 @@ void do_master_child(char **av)
 			perror("setreuid failed (in child)");
 			exit(1);
 		}
+		*flag = 1;
 #ifdef UCLINUX
 		if (self_exec(av[0], "") < 0) {
 			perror("self_exec failed");

@@ -175,10 +186,13 @@ void do_master_child(char **av)
 		exit(1);
 	}
 
+	/* wait until child sets its euid */
+	wait_for_flag(1);
+
 	TEST(kill(pid1, TEST_SIG));
 
 	/* signal the child that we're done */
-	*flag = 1;
+	*flag = 2;
 
 	if (waitpid(pid1, &status, 0) == -1) {
 		perror("waitpid failed");

@@ -204,13 +218,8 @@ void do_master_child(char **av)
 
 void do_child()
 {
-
-	while (1) {
-		if (*flag == 1)
-			exit(0);
-		else
-			sleep(1);
-	}
+	wait_for_flag(2);
+	exit(0);
 }
 
 void setup(void)

------------------------------------------------------------------------------
WhatsUp Gold - Download Free Network Management Software The most intuitive, comprehensive, and cost-effective network management toolset available today. Delivers lowest initial acquisition cost and overall TCO of any competing solution.
http://p.sf.net/sfu/whatsupgold-sd

_______________________________________________
Ltp-list mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/ltp-list

Committed -- thanks!
-Garrett

------------------------------------------------------------------------------
WhatsUp Gold - Download Free Network Management Software The most intuitive, comprehensive, and cost-effective network management toolset available today. Delivers lowest initial acquisition cost and overall TCO of any competing solution.
http://p.sf.net/sfu/whatsupgold-sd
_______________________________________________
Ltp-list mailing list [email protected]
https://lists.sourceforge.net/lists/listinfo/ltp-list