From 695153ac183e3e2aaea0961339007f34bf98d47c Mon Sep 17 00:00:00 2001
From: FRIGN <dev@frign.de>
Date: Wed, 11 Mar 2015 11:16:40 +0100
Subject: [PATCH] Audit cmp(1)

1) Remove the return-value-enum, which is not necessary for a simple
   program like this.
2) Don't disallow both l and s to be specified. This is undefined
   behaviour defined by POSIX, so we don't start demanding things
   from the user.
3) Replace exit() with return (we are in main).
4) Refactor main loop to never return in the loop, but actually
   set the same-value and break, which increases readability.
5) Remove the final fclose()'s. The OS will take care of them, no
   need to become cleansy here.
6) Use idiomatic return-value using same. This concludes the
   increase of readability in the main-loop.
---
 README |  2 +-
 cmp.c  | 34 ++++++++++++++--------------------
 2 files changed, 15 insertions(+), 21 deletions(-)

diff --git a/README b/README
index f5a17bb..132287b 100644
--- a/README
+++ b/README
@@ -17,7 +17,7 @@ The following tools are implemented ('*' == finished, '#' == UTF-8 support,
 =*| chown           yes                          none
 =*| chroot          non-posix                    none
 =*| cksum           yes                          none
-=*  cmp             yes                          none
+=*| cmp             yes                          none
 #*| cols            non-posix                    none
     col             yes                          none
 =*  comm            yes                          none
diff --git a/cmp.c b/cmp.c
index 9d9f41e..1e48c52 100644
--- a/cmp.c
+++ b/cmp.c
@@ -4,12 +4,10 @@
 
 #include "util.h"
 
-enum { Same = 0, Diff = 1, Error = 2 };
-
 static void
 usage(void)
 {
-	enprintf(Error, "usage: %s [-l | -s] file1 file2\n", argv0);
+	enprintf(2, "usage: %s [-l | -s] file1 file2\n", argv0);
 }
 
 int
@@ -30,7 +28,7 @@ main(int argc, char *argv[])
 		usage();
 	} ARGEND;
 
-	if (argc != 2 || (lflag && sflag))
+	if (argc != 2)
 		usage();
 
 	for (n = 0; n < 2; n++) {
@@ -38,11 +36,10 @@ main(int argc, char *argv[])
 			argv[n] = "<stdin>";
 			fp[n] = stdin;
 		} else {
-			fp[n] = fopen(argv[n], "r");
-			if (!fp[n]) {
+			if (!(fp[n] = fopen(argv[n], "r"))) {
 				if (!sflag)
 					weprintf("fopen %s:", argv[n]);
-				exit(Error);
+				return 2;
 			}
 		}
 	}
@@ -57,25 +54,22 @@ main(int argc, char *argv[])
 			else if (b[0] == '\n')
 				line++;
 			continue;
-		}
-		if (b[0] == EOF || b[1] == EOF) {
+		} else if (b[0] == EOF || b[1] == EOF) {
 			if (!sflag)
-				fprintf(stderr, "cmp: EOF on %s\n",
-				        argv[(b[0] == EOF) ? 0 : 1]);
-			exit(Diff);
-		}
-		if (!lflag) {
+				weprintf("cmp: EOF on %s\n", argv[(b[0] != EOF)]);
+			same = 0;
+			break;
+		} else if (!lflag) {
 			if (!sflag)
-				printf("%s %s differ: byte %ld, line %ld\n",
+				printf("%s %s differ: byte %zu, line %zu\n",
 				       argv[0], argv[1], n, line);
-			exit(Diff);
+			same = 0;
+			break;
 		} else {
-			printf("%ld %o %o\n", n, b[0], b[1]);
+			printf("%zu %o %o\n", n, b[0], b[1]);
 			same = 0;
 		}
 	}
-	fclose(fp[0]);
-	fclose(fp[1]);
 
-	return same ? Same : Diff;
+	return !same;
 }