From: Brian Norris <banorris@uci.edu>
Date: Fri, 5 Apr 2013 21:02:58 +0000 (-0700)
Subject: snapshot: clean up fork-based error handling
X-Git-Tag: oopsla2013~94
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=103b2cae595a3744095dd8432b62b138f24ec9eb;p=model-checker.git

snapshot: clean up fork-based error handling

This is an ugly attempt at error handling. Kill the useless variables,
reword the debug prints, and use perror().
---

diff --git a/snapshot.cc b/snapshot.cc
index 5069a1c..da47807 100644
--- a/snapshot.cc
+++ b/snapshot.cc
@@ -347,19 +347,19 @@ static void fork_snapshot_init(unsigned int numbackingpages,
 				setcontext(&savedUserSnapshotContext);
 			}
 		} else {
-			int status;
-			int retVal;
-
-			DEBUG("The process id of child is %d and the process id of this process is %d and snapshot id is %d\n",
-			        forkedID, getpid(), snapshotid);
-
-			do {
-				retVal = waitpid(forkedID, &status, 0);
-			} while (-1 == retVal && errno == EINTR);
+			DEBUG("parent PID: %d, child PID: %d, snapshot ID: %d\n",
+			        getpid(), forkedID, snapshotid);
+
+			while (waitpid(forkedID, NULL, 0) < 0) {
+				/* waitpid() may be interrupted */
+				if (errno != EINTR) {
+					perror("waitpid");
+					exit(EXIT_FAILURE);
+				}
+			}
 
-			if (fork_snap->mIDToRollback != snapshotid) {
+			if (fork_snap->mIDToRollback != snapshotid)
 				exit(EXIT_SUCCESS);
-			}
 			rollback = true;
 		}
 	}