From a5f316cfc8f40401d3ddf52e8e54a64252f930dd Mon Sep 17 00:00:00 2001
From: cem <cem@FreeBSD.org>
Date: Sun, 8 Jan 2017 06:50:53 +0000
Subject: [PATCH] chmod: Add SIGINFO handler

PR:		191884
Submitted by:	Dan McGregor <dan.mcgregor at usask.ca>
Reviewed by:	mjg@ (earlier version)
---
 bin/chmod/chmod.1 | 12 +++++++++++-
 bin/chmod/chmod.c | 17 +++++++++++++++--
 2 files changed, 26 insertions(+), 3 deletions(-)

diff --git a/bin/chmod/chmod.1 b/bin/chmod/chmod.1
index 7efaabcdefcf..9eec706e7436 100644
--- a/bin/chmod/chmod.1
+++ b/bin/chmod/chmod.1
@@ -32,7 +32,7 @@
 .\"	@(#)chmod.1	8.4 (Berkeley) 3/31/94
 .\" $FreeBSD$
 .\"
-.Dd April 20, 2015
+.Dd January 7, 2017
 .Dt CHMOD 1
 .Os
 .Sh NAME
@@ -106,6 +106,16 @@ option is specified.
 In addition, these options override each other and the
 command's actions are determined by the last one specified.
 .Pp
+If
+.Nm
+receives a
+.Dv SIGINFO
+signal (see the
+.Cm status
+argument for
+.Xr stty 1 ) ,
+then the current filename as well as the old and new modes are displayed.
+.Pp
 Only the owner of a file or the super-user is permitted to change
 the mode of a file.
 .Sh EXIT STATUS
diff --git a/bin/chmod/chmod.c b/bin/chmod/chmod.c
index a6f625b11e68..d6875f073326 100644
--- a/bin/chmod/chmod.c
+++ b/bin/chmod/chmod.c
@@ -49,14 +49,24 @@ __FBSDID("$FreeBSD$");
 #include <fcntl.h>
 #include <fts.h>
 #include <limits.h>
+#include <signal.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
 
+static volatile sig_atomic_t siginfo;
+
 static void usage(void);
 static int may_have_nfs4acl(const FTSENT *ent, int hflag);
 
+static void
+siginfo_handler(int sig __unused)
+{
+
+	siginfo = 1;
+}
+
 int
 main(int argc, char *argv[])
 {
@@ -125,6 +135,8 @@ done:	argv += optind;
 	if (argc < 2)
 		usage();
 
+	(void)signal(SIGINFO, siginfo_handler);
+
 	if (Rflag) {
 		if (hflag)
 			errx(1, "the -R and -h options may not be "
@@ -192,10 +204,10 @@ done:	argv += optind;
 		    && !fflag) {
 			warn("%s", p->fts_path);
 			rval = 1;
-		} else if (vflag) {
+		} else if (vflag || siginfo) {
 			(void)printf("%s", p->fts_path);
 
-			if (vflag > 1) {
+			if (vflag > 1 || siginfo) {
 				char m1[12], m2[12];
 
 				strmode(p->fts_statp->st_mode, m1);
@@ -207,6 +219,7 @@ done:	argv += optind;
 				    newmode, m2);
 			}
 			(void)printf("\n");
+			siginfo = 0;
 		}
 	}
 	if (errno)