From 868210a9fb35e1c41a3bc0f7bbc9081d33437f4d Mon Sep 17 00:00:00 2001
From: Ben Pfaff <blp@cs.stanford.edu>
Date: Tue, 30 May 2006 21:33:10 +0000
Subject: [PATCH] Fix stupidity in last check-in.

---
 src/utils/pintos | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/src/utils/pintos b/src/utils/pintos
index 079ab5a..13d7e54 100755
--- a/src/utils/pintos
+++ b/src/utils/pintos
@@ -703,7 +703,7 @@ sub xsystem {
 	    my ($boots) = 0;
 	    local ($|) = 1;
 	    for (;;) {
-		if (waitpid ($pid, WNOHANG) == 0) {
+		if (waitpid ($pid, WNOHANG) != 0) {
 		    # Subprocess died.  Pass through any remaining data.
 		    print $buf while sysread ($in, $buf, 4096) > 0;
 		    last;
@@ -711,7 +711,8 @@ sub xsystem {
 
 		# Read and print out pipe data.
 		my ($len) = length ($buf);
-		last if sysread ($in, $buf, 4096, $len) <= 0;
+		waitpid ($pid, 0), last
+		  if sysread ($in, $buf, 4096, $len) <= 0;
 		print substr ($buf, $len);
 
 		# Remove full lines from $buf and scan them for keywords.
@@ -730,8 +731,9 @@ sub xsystem {
 		    }
 		}
 	    }
+	} else {
+	    waitpid ($pid, 0);
 	}
-	waitpid ($pid, 0);
 	alarm (0);
 	&$cleanup ();
 
-- 
2.30.2