Allow custom files to be opened and allow sorting by timestamp.

While implementing a tool to import lastlog entries into utmpx, I
noticed lastlogin doesn't allow custom database files to be opened. Add
a -f switch to support this. Also, add -r and -t similar to ls(1),
ruptime(1), etc. where you can sort entries by timestamp and reverse
them. This allows you to spot active/idle users more easily.

2 files changed, 60 insertions, 18 deletions

diff --git a/usr.sbin/lastlogin/lastlogin.8 b/usr.sbin/lastlogin/lastlogin.8
index 0630163..fdbc871 100644
--- a/usr.sbin/lastlogin/lastlogin.8
+++ b/usr.sbin/lastlogin/lastlogin.8
@@ -31,7 +31,7 @@
 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 .\" SUCH DAMAGE.
 .\"
-.Dd January 11, 1996
+.Dd June 6, 2011
 .Dt LASTLOGIN 8
 .Os
 .Sh NAME
@@ -39,6 +39,8 @@
 .Nd indicate last login time of users
 .Sh SYNOPSIS
 .Nm
+.Op Fl f Ar file
+.Op Fl rt
 .Op Ar user ...
 .Sh DESCRIPTION
 The
@@ -54,8 +56,8 @@ If more than one
 .Ar user
 is given, the session information for each user is printed in
 the order given on the command line.
-Otherwise, information
-for all users is printed, sorted by name.
+Otherwise, information for all users is printed.
+By default, the entries are sorted by user name.
 .Pp
 The
 .Nm
@@ -63,6 +65,18 @@ utility differs from
 .Xr last 1
 in that it only prints information regarding the very last login session.
 The last login database is never turned over or deleted in standard usage.
+.Pp
+The following options are available:
+.Bl -tag -width indent
+.It Fl f Ar file
+Open last login database
+.Ar file
+instead of the system-wide database.
+.It Fl r
+Print the entries in reverse sorted order.
+.It Fl t
+Sort the elements by last login time, instead of user name.
+.El
 .Sh FILES
 .Bl -tag -width /var/log/utx.lastlogin -compact
 .It Pa /var/log/utx.lastlogin
diff --git a/usr.sbin/lastlogin/lastlogin.c b/usr.sbin/lastlogin/lastlogin.c
index 4c08547..2f8dd78 100644
--- a/usr.sbin/lastlogin/lastlogin.c
+++ b/usr.sbin/lastlogin/lastlogin.c
@@ -47,30 +47,59 @@ __RCSID("$NetBSD: lastlogin.c,v 1.4 1998/02/03 04:45:35 perry Exp $");
 	int	main(int, char **);
 static	void	output(struct utmpx *);
 static	void	usage(void);
+static int	utcmp_user(const void *, const void *);
+
+static int	order = 1;
+static const char *file = NULL;
+static int	(*utcmp)(const void *, const void *) = utcmp_user;
 
 static int
-utcmp(const void *u1, const void *u2)
+utcmp_user(const void *u1, const void *u2)
 {
 
-	return (strcmp(((const struct utmpx *)u1)->ut_user,
+	return (order * strcmp(((const struct utmpx *)u1)->ut_user,
 	    ((const struct utmpx *)u2)->ut_user));
 }
 
+static int
+utcmp_time(const void *u1, const void *u2)
+{
+	time_t t1, t2;
+
+	t1 = ((const struct utmpx *)u1)->ut_tv.tv_sec;
+	t2 = ((const struct utmpx *)u2)->ut_tv.tv_sec;
+	return (t1 < t2 ? order : t1 > t2 ? -order : 0);
+}
+
 int
 main(int argc, char *argv[])
 {
 	int	ch, i, ulistsize;
 	struct utmpx *u, *ulist;
 
-	while ((ch = getopt(argc, argv, "")) != -1) {
-		usage();
+	while ((ch = getopt(argc, argv, "f:rt")) != -1) {
+		switch (ch) {
+		case 'f':
+			file = optarg;
+			break;
+		case 'r':
+			order = -1;
+			break;
+		case 't':
+			utcmp = utcmp_time;
+			break;
+		default:
+			usage();
+		}
 	}
+	argc -= optind;
+	argv += optind;
 
-	/* Process usernames given on the command line. */
-	if (argc > 1) {
-		for (i = 1; i < argc; ++i) {
-			if (setutxdb(UTXDB_LASTLOGIN, NULL) != 0)
-				errx(1, "failed to open lastlog database");
+	if (argc > 0) {
+		/* Process usernames given on the command line. */
+		for (i = 0; i < argc; i++) {
+			if (setutxdb(UTXDB_LASTLOGIN, file) != 0)
+				err(1, "failed to open lastlog database");
 			if ((u = getutxuser(argv[i])) == NULL) {
 				warnx("user '%s' not found", argv[i]);
 				continue;
@@ -78,11 +107,10 @@ main(int argc, char *argv[])
 			output(u);
 			endutxent();
 		}
-	}
-	/* Read all lastlog entries, looking for active ones */
-	else {
-		if (setutxdb(UTXDB_LASTLOGIN, NULL) != 0)
-			errx(1, "failed to open lastlog database");
+	} else {
+		/* Read all lastlog entries, looking for active ones. */
+		if (setutxdb(UTXDB_LASTLOGIN, file) != 0)
+			err(1, "failed to open lastlog database");
 		ulist = NULL;
 		ulistsize = 0;
 		while ((u = getutxent()) != NULL) {
@@ -119,6 +147,6 @@ output(struct utmpx *u)
 static void
 usage(void)
 {
-	fprintf(stderr, "usage: lastlogin [user ...]\n");
+	fprintf(stderr, "usage: lastlogin [-f file] [-rt] [user ...]\n");
 	exit(1);
 }