[PATCH] last: fix ignoring the first login entry

[Dmitry Klochkov]

The first login entry is ignored if a log file contains more than one
entries. For example:

  $ utmpdump wtmp.two
  Utmp dump of wtmp.two
  [7] [07810] [ts/2] [username] [pts/2       ] [192.168.255.114     ] ...
  [8] [07810] [ts/2] [        ] [pts/2       ] [                    ] ...

  $ ln -sf $(realpath wtmp.two) /var/log/wtmp

  $ busybox last
  USER       TTY            HOST               LOGIN        TIME

  $ utmpdump wtmp.one
  Utmp dump of wtmp.one
  [7] [07810] [ts/2] [username] [pts/2       ] [192.168.255.114     ] ...

  $ ln -sf $(realpath wtmp.one) /var/log/wtmp

  $ busybox last
  USER       TTY            HOST               LOGIN        TIME
  username   pts/2          192.168.255.114    May 14 11:12

To fix it, do not break the while loop if the offset is zero.
---
 util-linux/last.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/util-linux/last.c b/util-linux/last.c
index 7530d013d..aafd01bb9 100644
--- a/util-linux/last.c
+++ b/util-linux/last.c
@@ -157,7 +157,7 @@ int last_main(int argc UNUSED_PARAM, char **argv UNUSED_PARAM)
 			ut.ut_user, ut.ut_line, ut.ut_host, ctime(&t_tmp) + 4);
  next:
 		pos -= sizeof(ut);
-		if (pos <= 0)
+		if (pos < 0)
 			break; /* done. */
 		xlseek(file, pos, SEEK_SET);
 	}
-- 
2.49.0