Affect the first of stdin, stdout and stderr that is attached to a terminal.

Write status information to stdout instead of stderr.
Exit status when an error occurs musn't be 1, that is reserved for
indicating that messages are disabled.

These changes bring mesg(1) up to SUSv3 conformance.

Reviewed by:	mike

1 files changed, 9 insertions, 7 deletions

diff --git a/usr.bin/mesg/mesg.c b/usr.bin/mesg/mesg.c
index d80acb6..dcd14c3 100644
--- a/usr.bin/mesg/mesg.c
+++ b/usr.bin/mesg/mesg.c
@@ -79,28 +79,30 @@ main(argc, argv)
 	argc -= optind;
 	argv += optind;
 
-	if ((tty = ttyname(STDERR_FILENO)) == NULL)
-		err(1, "ttyname");
+	if ((tty = ttyname(STDIN_FILENO)) == NULL &&
+	    (tty = ttyname(STDOUT_FILENO)) == NULL &&
+	    (tty = ttyname(STDERR_FILENO)) == NULL)
+		err(2, "ttyname");
 	if (stat(tty, &sb) < 0)
-		err(1, "%s", tty);
+		err(2, "%s", tty);
 
 	if (*argv == NULL) {
 		if (sb.st_mode & S_IWGRP) {
-			(void)fprintf(stderr, "is y\n");
+			(void)puts("is y");
 			exit(0);
 		}
-		(void)fprintf(stderr, "is n\n");
+		(void)puts("is n");
 		exit(1);
 	}
 
 	switch (*argv[0]) {
 	case 'y':
 		if (chmod(tty, sb.st_mode | S_IWGRP) < 0)
-			err(1, "%s", tty);
+			err(2, "%s", tty);
 		exit(0);
 	case 'n':
 		if (chmod(tty, sb.st_mode & ~S_IWGRP) < 0)
-			err(1, "%s", tty);
+			err(2, "%s", tty);
 		exit(1);
 	}