From 8dd5832395c6a0b12e11b37c062e4c11be3c82ef Mon Sep 17 00:00:00 2001 From: Sami Kerola Date: Thu, 2 Aug 2018 19:35:51 +0100 Subject: mesg: do not print 'ttyname failed' message unless --verbose requested Lots of people are confused why mesg(1) is priting this message. Usual cause seems to be an uninteractive shell trying to turn running 'mesg n' from a /root/.profile where command invocation is by default on debian based systems. This might be rare case when failing silently is better. [kzak@redhat.com: - add note to the man page - fix if(isatty()) logic] Reference: https://www.google.com/search?q=mesg+ttyname+failed Review: https://marc.info/?l=util-linux-ng&m=153319988631233&w=2 Signed-off-by: Sami Kerola Signed-off-by: Karel Zak --- term-utils/mesg.1 | 9 +++++++++ term-utils/mesg.c | 5 +++++ 2 files changed, 14 insertions(+) (limited to 'term-utils') diff --git a/term-utils/mesg.1 b/term-utils/mesg.1 index b7e73a594..15c834dd7 100644 --- a/term-utils/mesg.1 +++ b/term-utils/mesg.1 @@ -55,6 +55,15 @@ write access by default, at least for the primary login shell. To make sure your ttys are set the way you want them to be set, .B mesg should be executed in your login scripts. +.PP +The +.B mesg +utility silently exits with error status 2 if the current standard error output does +not refer to the terminal. In this case execute +.B mesg +is pointless. The command line option \fB\-\-verbose\fR forces +mesg to print a warning in this situation. This behaviour has been introduced +in version 2.33. .SH ARGUMENTS .TP .B n diff --git a/term-utils/mesg.c b/term-utils/mesg.c index 8714ad1aa..608f3cf61 100644 --- a/term-utils/mesg.c +++ b/term-utils/mesg.c @@ -121,6 +121,11 @@ int main(int argc, char *argv[]) argc -= optind; argv += optind; + if (!isatty(STDERR_FILENO)) { + if (verbose) + warnx(_("no tty")); + exit(MESG_EXIT_FAILURE); + } if ((tty = ttyname(STDERR_FILENO)) == NULL) err(MESG_EXIT_FAILURE, _("ttyname failed")); if ((fd = open(tty, O_RDONLY)) < 0) -- cgit v1.2.3-55-g7522