From 85793595bf5d79e27873298112031afbae4895c6 Mon Sep 17 00:00:00 2001
From: kleink <kleink@NetBSD.org>
Date: Mon, 19 May 1997 10:01:52 +0000
Subject: [PATCH] Fix lossage revealed by the recent `lseek() vs. negative
 offsets' changes; from John F. Woods <jfw@jfwhome.funhouse.com> in PR/3634.

---
 usr.bin/lastcomm/lastcomm.c | 47 +++++++++++++++++++------------------
 1 file changed, 24 insertions(+), 23 deletions(-)

diff --git a/usr.bin/lastcomm/lastcomm.c b/usr.bin/lastcomm/lastcomm.c
index 4391165c1083..bc7f43b283fe 100644
--- a/usr.bin/lastcomm/lastcomm.c
+++ b/usr.bin/lastcomm/lastcomm.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: lastcomm.c,v 1.9 1995/10/22 01:43:42 ghudson Exp $	*/
+/*	$NetBSD: lastcomm.c,v 1.10 1997/05/19 10:01:52 kleink Exp $	*/
 
 /*
  * Copyright (c) 1980, 1993
@@ -43,7 +43,7 @@ static char copyright[] =
 #if 0
 static char sccsid[] = "@(#)lastcomm.c	8.2 (Berkeley) 4/29/95";
 #endif
-static char rcsid[] = "$NetBSD: lastcomm.c,v 1.9 1995/10/22 01:43:42 ghudson Exp $";
+static char rcsid[] = "$NetBSD: lastcomm.c,v 1.10 1997/05/19 10:01:52 kleink Exp $";
 #endif /* not lint */
 
 #include <sys/param.h>
@@ -124,13 +124,6 @@ main(argc, argv)
 		if (fread(&ab, sizeof(struct acct), 1, fp) != 1)
 			err(1, "%s", acctfile);
 
-		if (fseek(fp, 2 * -(long)sizeof(struct acct), SEEK_CUR) == -1)
-			err(1, "%s", acctfile);
-
-		if (size == 0)
-			break;
-		size -= sizeof(struct acct);
-
 		if (ab.ac_comm[0] == '\0') {
 			ab.ac_comm[0] = '?';
 			ab.ac_comm[1] = '\0';
@@ -139,21 +132,29 @@ main(argc, argv)
 			    p < &ab.ac_comm[fldsiz(acct, ac_comm)] && *p; ++p)
 				if (!isprint(*p))
 					*p = '?';
-		if (*argv && !requested(argv, &ab))
-			continue;
+		if (!*argv || requested(argv, &ab)) {
 
-		t = expand(ab.ac_utime) + expand(ab.ac_stime);
-		(void)printf(
-                    "%-*.*s %-7s %-*.*s %-*.*s %6.2f secs %.16s",
-		    fldsiz(acct, ac_comm), fldsiz(acct, ac_comm), ab.ac_comm,
-		    flagbits(ab.ac_flag), UT_NAMESIZE, UT_NAMESIZE,
-		    user_from_uid(ab.ac_uid, 0), UT_LINESIZE, UT_LINESIZE,
-		    getdev(ab.ac_tty), t / (double)AHZ, ctime(&ab.ac_btime));
-		delta = expand(ab.ac_etime) / (double)AHZ;
- 	        printf(" (%1.0lf:%02.0lf:%05.2lf)\n",
-		    delta / SECSPERHOUR,
-		    fmod(delta, SECSPERHOUR) / SECSPERMIN,
-		    fmod(delta, SECSPERMIN));
+			t = expand(ab.ac_utime) + expand(ab.ac_stime);
+			(void)printf(
+				     "%-*.*s %-7s %-*.*s %-*.*s %6.2f secs %.16s",
+				     fldsiz(acct, ac_comm), fldsiz(acct, ac_comm), ab.ac_comm,
+				     flagbits(ab.ac_flag), UT_NAMESIZE, UT_NAMESIZE,
+				     user_from_uid(ab.ac_uid, 0), UT_LINESIZE, UT_LINESIZE,
+				     getdev(ab.ac_tty), t / (double)AHZ, ctime(&ab.ac_btime));
+			delta = expand(ab.ac_etime) / (double)AHZ;
+			printf(" (%1.0lf:%02.0lf:%05.2lf)\n",
+			       delta / SECSPERHOUR,
+			       fmod(delta, SECSPERHOUR) / SECSPERMIN,
+			       fmod(delta, SECSPERMIN));
+		}
+		/* are we at the beginning of the file yet? */
+		if (size == 0)
+			break;
+		/* seek backward over the one we read and the next to read */
+		if (fseek(fp, 2 * -(long)sizeof(struct acct), SEEK_CUR) == -1)
+			err(1, "%s", acctfile);
+		/* and account for its size */
+		size -= sizeof(struct acct);
 	}
 	exit(0);
 }