From bfe87da86175d846ac84dd8bd66c3992995a32de Mon Sep 17 00:00:00 2001
From: Andrea Smith <smit9523@umn.edu>
Date: Wed, 4 Nov 2020 10:55:07 -0600
Subject: Added error handling

---
 P2/lib/utils.c | 21 ++++++++++++++++-----
 1 file changed, 16 insertions(+), 5 deletions(-)

diff --git a/P2/lib/utils.c b/P2/lib/utils.c
index b8922d4..21753a1 100644
--- a/P2/lib/utils.c
+++ b/P2/lib/utils.c
@@ -45,14 +45,17 @@ void sendChunkData(char *inputFile, int nMappers) {
 		while(validChar(message.msgText[i])) {
 			message.msgText[i--] = '\0';
 		}
-		fseek(file, (i - 1023), SEEK_CUR);
+		if (fseek(file, (i - 1023), SEEK_CUR) == -1) {
+			break;
 		message.msgType = (map++ % nMappers) + 1;
 	
-		msgsnd(msgid, &message, MSGSIZE, 0);
+		if (msgsnd(msgid, &message, MSGSIZE, 0) == -1)
+			break;
 	}
 	for (int i = 1; i <= nMappers; i++) {
 		struct msgBuffer END = {i, "END"};
-		msgsnd(msgid, &END, MSGSIZE, 0);
+		if (msgsnd(msgid, &END, MSGSIZE, 0) == -1)
+			break;
 	}
 	fclose(file);
 }
@@ -73,7 +76,10 @@ int getInterData(char *Qkey, int reducerID) {
 	struct msgBuffer message= makeMessage();
 	//DEBUG! make sure it work.
 	int id = openQueue();
-	msgrcv(id, &message, MSGSIZE, reducerID, 0);
+	if (id == -1)
+		exit(-1);
+	if (msgrcv(id, &message, MSGSIZE, reducerID, 0) == -1)
+		exit(-1);
 	strcpy(Qkey, message.msgText);
 	return (strncmp("END", message.msgText, 3) != 0);
 }
@@ -87,19 +93,24 @@ void shuffle(int nMappers, int nReducers) {
 		char newpath[100];
 		sprintf(newpath, "output/MapOut/Map_%d", i); // Removed /, add to current dir
 		DIR *dir = opendir(newpath);
+		if (dir == NULL)
+			break;
 		struct dirent* entry;
 		while ((entry = readdir(dir)) != NULL) {
 			if (!strcmp(".", entry->d_name) || !strcmp("..", entry->d_name))
 				continue;
 			sprintf(message.msgText, "%s/%s", newpath, entry -> d_name);
 			message.msgType = (hashFunction(entry -> d_name, nReducers)+1);
-			msgsnd(id, &message, MSGSIZE, 0);
+			if (msgsnd(id, &message, MSGSIZE, 0) == -1)
+				break;
 			}
 		closedir(dir);
 	}
 	for (int i = 1; i <= nReducers; i++) {
 		struct msgBuffer END = {i, "END"};
 		msgsnd(id, &END, MSGSIZE, 0);
+		if (msgsnd(id, &END, MSGSIZE, 0))
+			break;
 	}
 }
 
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