From 50950530362d67fae2ff7525e4cd851ca2f8475d Mon Sep 17 00:00:00 2001
From: Ed Schouten <ed@FreeBSD.org>
Date: Sat, 5 Dec 2009 20:22:26 +0000
Subject: [PATCH] Let wall(1) use utmpx.

Because our implementation guarantees the strings inside struct utmpx to
be null terminated, we don't need to copy everything out, which makes
the code nicer to read.

Also set WARNS to 6 and add $FreeBSD$ to keep SVN happy.
---
 usr.bin/write/Makefile |  6 ++++++
 usr.bin/write/write.c  | 49 +++++++++++++++++++-----------------------
 2 files changed, 28 insertions(+), 27 deletions(-)

diff --git a/usr.bin/write/Makefile b/usr.bin/write/Makefile
index 8e6454bdc45..e34a61d8be6 100644
--- a/usr.bin/write/Makefile
+++ b/usr.bin/write/Makefile
@@ -1,7 +1,13 @@
 #	@(#)Makefile	8.1 (Berkeley) 6/6/93
+# $FreeBSD$
 
 PROG=	write
 BINMODE=2555
 BINGRP=	tty
 
+WARNS?=	6
+
+DPADD=	${LIBULOG}
+LDADD=	-lulog
+
 .include <bsd.prog.mk>
diff --git a/usr.bin/write/write.c b/usr.bin/write/write.c
index 878c8c1d0ba..ed57cb1815b 100644
--- a/usr.bin/write/write.c
+++ b/usr.bin/write/write.c
@@ -62,8 +62,9 @@ __FBSDID("$FreeBSD$");
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#define	_ULOG_POSIX_NAMES
+#include <ulog.h>
 #include <unistd.h>
-#include <utmp.h>
 
 void done(int);
 void do_write(char *, char *, uid_t);
@@ -146,20 +147,17 @@ usage(void)
 int
 utmp_chk(char *user, char *tty)
 {
-	struct utmp u;
-	int ufd;
+	struct utmpx lu, *u;
 
-	if ((ufd = open(_PATH_UTMP, O_RDONLY)) < 0)
-		return(0);	/* ignore error, shouldn't happen anyway */
-
-	while (read(ufd, (char *) &u, sizeof(u)) == sizeof(u))
-		if (strncmp(user, u.ut_name, sizeof(u.ut_name)) == 0 &&
-		    strncmp(tty, u.ut_line, sizeof(u.ut_line)) == 0) {
-			(void)close(ufd);
+	strncpy(lu.ut_line, tty, sizeof lu.ut_line);
+	setutxent();
+	while ((u = getutxline(&lu)) != NULL)
+		if (u->ut_type == USER_PROCESS &&
+		    strcmp(user, u->ut_user) == 0) {
+			endutxent();
 			return(0);
 		}
-
-	(void)close(ufd);
+	endutxent();
 	return(1);
 }
 
@@ -177,43 +175,40 @@ utmp_chk(char *user, char *tty)
 void
 search_utmp(char *user, char *tty, char *mytty, uid_t myuid)
 {
-	struct utmp u;
+	struct utmpx *u;
 	time_t bestatime, atime;
-	int ufd, nloggedttys, nttys, msgsok, user_is_me;
-	char atty[UT_LINESIZE + 1];
-
-	if ((ufd = open(_PATH_UTMP, O_RDONLY)) < 0)
-		err(1, "utmp");
+	int nloggedttys, nttys, msgsok, user_is_me;
 
 	nloggedttys = nttys = 0;
 	bestatime = 0;
 	user_is_me = 0;
-	while (read(ufd, (char *) &u, sizeof(u)) == sizeof(u))
-		if (strncmp(user, u.ut_name, sizeof(u.ut_name)) == 0) {
+
+	setutxent();
+	while ((u = getutxent()) != NULL)
+		if (u->ut_type == USER_PROCESS &&
+		    strcmp(user, u->ut_user) == 0) {
 			++nloggedttys;
-			(void)strncpy(atty, u.ut_line, UT_LINESIZE);
-			atty[UT_LINESIZE] = '\0';
-			if (term_chk(atty, &msgsok, &atime, 0))
+			if (term_chk(u->ut_line, &msgsok, &atime, 0))
 				continue;	/* bad term? skip */
 			if (myuid && !msgsok)
 				continue;	/* skip ttys with msgs off */
-			if (strcmp(atty, mytty) == 0) {
+			if (strcmp(u->ut_line, mytty) == 0) {
 				user_is_me = 1;
 				continue;	/* don't write to yourself */
 			}
 			++nttys;
 			if (atime > bestatime) {
 				bestatime = atime;
-				(void)strcpy(tty, atty);
+				(void)strlcpy(tty, u->ut_line, MAXPATHLEN);
 			}
 		}
+	endutxent();
 
-	(void)close(ufd);
 	if (nloggedttys == 0)
 		errx(1, "%s is not logged in", user);
 	if (nttys == 0) {
 		if (user_is_me) {		/* ok, so write to yourself! */
-			(void)strcpy(tty, mytty);
+			(void)strlcpy(tty, mytty, MAXPATHLEN);
 			return;
 		}
 		errx(1, "%s has messages disabled", user);