Let rwhod use libulog.

I am not planning on providing a mechanism tot stat() the database files
directly. The disadvantage of this, is that rwhod will now be a little
bit more heavy than it used to be. It normally used to fstat() the file
descriptor to see whether the file had changed, but this is now
impossible to implement, meaning we have to parse the entire utmp file
each 180 seconds.

This is probably not an issue on modern 16-way servers, but if it turns
out to be a problem, we'll think of something.

2 files changed, 30 insertions, 62 deletions

diff --git a/usr.sbin/rwhod/Makefile b/usr.sbin/rwhod/Makefile
index def0e6e..6f99d56 100644
--- a/usr.sbin/rwhod/Makefile
+++ b/usr.sbin/rwhod/Makefile
@@ -7,4 +7,7 @@ MAN=	rwhod.8
 # XXX breaks on Alpha due to alignment constraints
 #WARNS?=	4
 
+DPADD=	${LIBULOG}
+LDADD=	-lulog
+
 .include <bsd.prog.mk>
diff --git a/usr.sbin/rwhod/rwhod.c b/usr.sbin/rwhod/rwhod.c
index 96fd9ec..9679fae 100644
--- a/usr.sbin/rwhod/rwhod.c
+++ b/usr.sbin/rwhod/rwhod.c
@@ -67,8 +67,9 @@ __FBSDID("$FreeBSD$");
 #include <string.h>
 #include <syslog.h>
 #include <timeconv.h>
+#define	_ULOG_POSIX_NAMES
+#include <ulog.h>
 #include <unistd.h>
-#include <utmp.h>
 #include <pwd.h>
 #include <grp.h>
 
@@ -146,7 +147,7 @@ struct	neighbor {
 struct	neighbor *neighbors;
 struct	whod mywd;
 struct	servent *sp;
-int	s, utmpf;
+int	s;
 
 #define	WHDRSIZE	(int)(sizeof(mywd) - sizeof(mywd.wd_we))
 
@@ -231,11 +232,6 @@ main(int argc, char *argv[])
 		*cp = '\0';
 	strncpy(mywd.wd_hostname, myname, sizeof(mywd.wd_hostname) - 1);
 	mywd.wd_hostname[sizeof(mywd.wd_hostname) - 1] = '\0';
-	utmpf = open(_PATH_UTMP, O_RDONLY|O_CREAT, 0644);
-	if (utmpf < 0) {
-		syslog(LOG_ERR, "%s: %m", _PATH_UTMP);
-		exit(1);
-	}
 	getboottime(0);
 	if ((s = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
 		syslog(LOG_ERR, "socket: %m");
@@ -383,73 +379,43 @@ verify(name, maxlen)
 	return (size > 0);
 }
 
-int	utmptime;
-int	utmpent;
-int	utmpsize = 0;
-struct	utmp *utmp;
-int	alarmcount;
-
 void
-onalrm(signo)
-	int signo __unused;
+onalrm(int signo __unused)
 {
-	register struct neighbor *np;
-	register struct whoent *we = mywd.wd_we, *wlast;
-	register int i;
+	struct neighbor *np;
+	struct whoent *we = mywd.wd_we, *wend;
 	struct stat stb;
+	struct utmpx *ut;
+	static int alarmcount = 0;
 	double avenrun[3];
 	time_t now;
-	int cc;
+	int i, cc;
 
 	now = time(NULL);
 	if (alarmcount % 10 == 0)
 		getboottime(0);
 	alarmcount++;
-	(void) fstat(utmpf, &stb);
-	if ((stb.st_mtime != utmptime) || (stb.st_size > utmpsize)) {
-		utmptime = stb.st_mtime;
-		if (stb.st_size > utmpsize) {
-			utmpsize = stb.st_size + 10 * sizeof(struct utmp);
-			utmp = (struct utmp *)reallocf(utmp, utmpsize);
-			if (utmp == NULL) {
-				syslog(LOG_WARNING, "malloc failed");
-				utmpsize = 0;
-				goto done;
-			}
-		}
-		(void) lseek(utmpf, (off_t)0, L_SET);
-		cc = read(utmpf, (char *)utmp, stb.st_size);
-		if (cc < 0) {
-			syslog(LOG_ERR, "read(%s): %m", _PATH_UTMP);
-			goto done;
-		}
-		wlast = &mywd.wd_we[1024 / sizeof(struct whoent) - 1];
-		utmpent = cc / sizeof(struct utmp);
-		for (i = 0; i < utmpent; i++)
-			if (utmp[i].ut_name[0]) {
-				memcpy(we->we_utmp.out_line, utmp[i].ut_line,
-				   sizeof(utmp[i].ut_line));
-				memcpy(we->we_utmp.out_name, utmp[i].ut_name,
-				   sizeof(utmp[i].ut_name));
-				we->we_utmp.out_time = htonl(utmp[i].ut_time);
-				if (we >= wlast)
-					break;
-				we++;
-			}
-		utmpent = we - mywd.wd_we;
+	wend = &mywd.wd_we[1024 / sizeof(struct whoent)];
+	setutxent();
+	while ((ut = getutxent()) != NULL && we < wend) {
+		if (ut->ut_type != USER_PROCESS)
+			continue;
+		strncpy(we->we_utmp.out_line, ut->ut_line,
+		   sizeof(we->we_utmp.out_line));
+		strncpy(we->we_utmp.out_name, ut->ut_user,
+		   sizeof(we->we_utmp.out_name));
+		we->we_utmp.out_time =
+		    htonl(_time_to_time32(ut->ut_tv.tv_sec));
+		we++;
 	}
+	endutxent();
 
-	/*
-	 * The test on utmpent looks silly---after all, if no one is
-	 * logged on, why worry about efficiency?---but is useful on
-	 * (e.g.) compute servers.
-	 */
-	if (utmpent && chdir(_PATH_DEV)) {
+	if (chdir(_PATH_DEV)) {
 		syslog(LOG_ERR, "chdir(%s): %m", _PATH_DEV);
 		exit(1);
 	}
-	we = mywd.wd_we;
-	for (i = 0; i < utmpent; i++) {
+	wend = we;
+	for (we = mywd.wd_we; we < wend; we++) {
 		if (stat(we->we_utmp.out_line, &stb) >= 0)
 			we->we_idle = htonl(now - stb.st_atime);
 		we++;
@@ -457,7 +423,7 @@ onalrm(signo)
 	(void)getloadavg(avenrun, sizeof(avenrun)/sizeof(avenrun[0]));
 	for (i = 0; i < 3; i++)
 		mywd.wd_loadav[i] = htonl((u_long)(avenrun[i] * 100));
-	cc = (char *)we - (char *)&mywd;
+	cc = (char *)wend - (char *)&mywd;
 	mywd.wd_sendtime = htonl(_time_to_time32(time(NULL)));
 	mywd.wd_vers = WHODVERSION;
 	mywd.wd_type = WHODTYPE_STATUS;
@@ -485,11 +451,10 @@ onalrm(signo)
 		} else (void) sendto(s, (char *)&mywd, cc, 0,
 					np->n_addr, np->n_addrlen);
 	}
-	if (utmpent && chdir(_PATH_RWHODIR)) {
+	if (chdir(_PATH_RWHODIR)) {
 		syslog(LOG_ERR, "chdir(%s): %m", _PATH_RWHODIR);
 		exit(1);
 	}
-done:
 	(void) alarm(AL_INTERVAL);
 }