[src/trunk]: src/bin/cat Coverity complaint fixes:

[spz <spz%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/0fa7c1a77470
branches:  trunk
changeset: 325074:0fa7c1a77470
user:      spz <spz%NetBSD.org@localhost>
date:      Tue Dec 03 17:06:51 2013 +0000

description:
Coverity complaint fixes:
bin/cat/cat.c 976654 Argument cannot be negative
                     (missing check for fileno result, stdout)
bin/cat/cat.c 976653 Improper use of negative value
                     (missing check for fileno result, stdin)

diffstat:

 bin/cat/cat.c |  15 ++++++++++-----
 1 files changed, 10 insertions(+), 5 deletions(-)

diffs (51 lines):

diff -r 0dc28c8d3dca -r 0fa7c1a77470 bin/cat/cat.c
--- a/bin/cat/cat.c     Tue Dec 03 17:01:04 2013 +0000
+++ b/bin/cat/cat.c     Tue Dec 03 17:06:51 2013 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: cat.c,v 1.52 2012/11/19 19:41:31 christos Exp $    */
+/* $NetBSD: cat.c,v 1.53 2013/12/03 17:06:51 spz Exp $ */
 
 /*
  * Copyright (c) 1989, 1993
@@ -44,7 +44,7 @@
 #if 0
 static char sccsid[] = "@(#)cat.c      8.2 (Berkeley) 4/27/95";
 #else
-__RCSID("$NetBSD: cat.c,v 1.52 2012/11/19 19:41:31 christos Exp $");
+__RCSID("$NetBSD: cat.c,v 1.53 2013/12/03 17:06:51 spz Exp $");
 #endif
 #endif /* not lint */
 
@@ -250,9 +250,11 @@
        filename = "stdin";
        do {
                if (*argv) {
-                       if (!strcmp(*argv, "-"))
+                       if (!strcmp(*argv, "-")) {
                                fd = fileno(stdin);
-                       else if (fflag) {
+                               if (fd < 0)
+                                       goto skip;
+                       } else if (fflag) {
                                struct stat st;
                                fd = open(*argv, O_RDONLY|O_NONBLOCK, 0);
                                if (fd < 0)
@@ -279,7 +281,8 @@
                        filename = *argv++;
                }
                raw_cat(fd);
-               if (fd != fileno(stdin))
+               /* fd > 0 would be cuter but let's priorize human-readability */
+               if (fd >= 0 && fd != fileno(stdin))
                        (void)close(fd);
        } while (*argv);
 }
@@ -294,6 +297,8 @@
        int wfd;
 
        wfd = fileno(stdout);
+       if (wfd < 0)
+               err(EXIT_FAILURE, "stdout");
        if (buf == NULL) {
                struct stat sbuf;