As suggested by guenther@ and millert@, replace seek+[read|write] with

p[read|write].  Makes the code much clearer by eliminating extra error
checking and verbiage.

No intentional functional change.

Tweaks by and ok guenther@

7 files changed, 32 insertions, 67 deletions

diff --git a/bin/df/df.c b/bin/df/df.c
index 6ae73ca3f8c..7cfe89bf7f3 100644
--- a/bin/df/df.c
+++ b/bin/df/df.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: df.c,v 1.50 2009/10/27 23:59:21 deraadt Exp $	*/
+/*	$OpenBSD: df.c,v 1.51 2014/05/20 21:11:16 krw Exp $	*/
 /*	$NetBSD: df.c,v 1.21.2.1 1995/11/01 00:06:11 jtc Exp $	*/
 
 /*
@@ -445,8 +445,7 @@ bread(int rfd, off_t off, void *buf, int cnt)
 {
 	int nr;
 
-	(void)lseek(rfd, off, SEEK_SET);
-	if ((nr = read(rfd, buf, cnt)) != cnt) {
+	if ((nr = pread(rfd, buf, cnt, off)) != cnt) {
 		/* Probably a dismounted disk if errno == EIO. */
 		if (errno != EIO)
 			(void)fprintf(stderr, "\ndf: %qd: %s\n",
diff --git a/sbin/dump/traverse.c b/sbin/dump/traverse.c
index 736922d774c..e61f0bc6d7e 100644
--- a/sbin/dump/traverse.c
+++ b/sbin/dump/traverse.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: traverse.c,v 1.28 2013/11/12 04:59:02 deraadt Exp $	*/
+/*	$OpenBSD: traverse.c,v 1.29 2014/05/20 21:11:16 krw Exp $	*/
 /*	$NetBSD: traverse.c,v 1.17 1997/06/05 11:13:27 lukem Exp $	*/
 
 /*-
@@ -803,9 +803,8 @@ bread(daddr_t blkno, char *buf, int size)
 	int cnt, i;
 
 loop:
-	if (lseek(diskfd, ((off_t)blkno << dev_bshift), SEEK_SET) < 0)
-		msg("bread: lseek fails\n");
-	if ((cnt = read(diskfd, buf, size)) == size)
+	if ((cnt = pread(diskfd, buf, size, (off_t)blkno << dev_bshift)) ==
+		size)
 		return;
 	if (blkno + (size / dev_bsize) > fsbtodb(sblock, sblock->fs_ffs1_size)) {
 		/*
@@ -843,9 +842,8 @@ loop:
 	 */
 	memset(buf, 0, size);
 	for (i = 0; i < size; i += dev_bsize, buf += dev_bsize, blkno++) {
-		if (lseek(diskfd, ((off_t)blkno << dev_bshift), SEEK_SET) < 0)
-			msg("bread: lseek2 fails!\n");
-		if ((cnt = read(diskfd, buf, (int)dev_bsize)) == dev_bsize)
+		if ((cnt = pread(diskfd, buf, dev_bsize,
+			    (off_t)blkno << dev_bshift)) == dev_bsize)
 			continue;
 		if (cnt == -1) {
 			msg("read error from %s: %s: [sector %lld]: count=%ld\n",
diff --git a/sbin/fsck_ext2fs/utilities.c b/sbin/fsck_ext2fs/utilities.c
index 81f74d0521b..3fe2436fcec 100644
--- a/sbin/fsck_ext2fs/utilities.c
+++ b/sbin/fsck_ext2fs/utilities.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: utilities.c,v 1.19 2011/03/12 17:50:47 deraadt Exp $	*/
+/*	$OpenBSD: utilities.c,v 1.20 2014/05/20 21:11:16 krw Exp $	*/
 /*	$NetBSD: utilities.c,v 1.6 2001/02/04 21:19:34 christos Exp $	*/
 
 /*
@@ -286,19 +286,14 @@ bread(int fd, char *buf, daddr32_t blk, long size)
 
 	offset = blk;
 	offset *= dev_bsize;
-	if (lseek(fd, offset, SEEK_SET) < 0)
-		rwerror("SEEK", blk);
-	else if (read(fd, buf, (int)size) == size)
+	if (pread(fd, buf, size, offset) == size)
 		return (0);
 	rwerror("READ", blk);
-	if (lseek(fd, offset, SEEK_SET) < 0)
-		rwerror("SEEK", blk);
 	errs = 0;
 	memset(buf, 0, (size_t)size);
 	printf("THE FOLLOWING DISK SECTORS COULD NOT BE READ:");
 	for (cp = buf, i = 0; i < size; i += secsize, cp += secsize) {
-		if (read(fd, cp, (int)secsize) != secsize) {
-			(void)lseek(fd, offset + i + secsize, SEEK_SET);
+		if (pread(fd, cp, secsize, offset + i) != secsize) {
 			if (secsize != dev_bsize && dev_bsize != 1)
 				printf(" %ld (%ld),",
 				    (blk * dev_bsize + i) / secsize,
@@ -323,19 +318,14 @@ bwrite(int fd, char *buf, daddr32_t blk, long size)
 		return;
 	offset = blk;
 	offset *= dev_bsize;
-	if (lseek(fd, offset, SEEK_SET) < 0)
-		rwerror("SEEK", blk);
-	else if (write(fd, buf, (int)size) == size) {
+	if (pwrite(fd, buf, size, offset) == size) {
 		fsmodified = 1;
 		return;
 	}
 	rwerror("WRITE", blk);
-	if (lseek(fd, offset, SEEK_SET) < 0)
-		rwerror("SEEK", blk);
 	printf("THE FOLLOWING SECTORS COULD NOT BE WRITTEN:");
 	for (cp = buf, i = 0; i < size; i += dev_bsize, cp += dev_bsize)
-		if (write(fd, cp, (int)dev_bsize) != dev_bsize) {
-			(void)lseek(fd, offset + i + dev_bsize, SEEK_SET);
+		if (pwrite(fd, cp, dev_bsize, offset + i) != dev_bsize) {
 			printf(" %ld,", blk + i / dev_bsize);
 		}
 	printf("\n");
diff --git a/sbin/fsck_ffs/utilities.c b/sbin/fsck_ffs/utilities.c
index 6793460e5a9..475b83a76f8 100644
--- a/sbin/fsck_ffs/utilities.c
+++ b/sbin/fsck_ffs/utilities.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: utilities.c,v 1.43 2014/05/09 13:19:34 krw Exp $	*/
+/*	$OpenBSD: utilities.c,v 1.44 2014/05/20 21:11:16 krw Exp $	*/
 /*	$NetBSD: utilities.c,v 1.18 1996/09/27 22:45:20 christos Exp $	*/
 
 /*
@@ -339,19 +339,14 @@ bread(int fd, char *buf, daddr_t blk, long size)
 
 	offset = blk;
 	offset *= DEV_BSIZE;
-	if (lseek(fd, offset, SEEK_SET) < 0)
-		rwerror("SEEK", blk);
-	else if (read(fd, buf, (int)size) == size)
+	if (pread(fd, buf, size, offset) == size)
 		return (0);
 	rwerror("READ", blk);
-	if (lseek(fd, offset, SEEK_SET) < 0)
-		rwerror("SEEK", blk);
 	errs = 0;
 	memset(buf, 0, (size_t)size);
 	printf("THE FOLLOWING DISK SECTORS COULD NOT BE READ:");
 	for (cp = buf, i = 0; i < size; i += secsize, cp += secsize) {
-		if (read(fd, cp, (int)secsize) != secsize) {
-			(void)lseek(fd, offset + i + secsize, SEEK_SET);
+		if (pread(fd, cp, secsize, offset + i) != secsize) {
 			if (secsize != DEV_BSIZE)
 				printf(" %lld (%lld),",
 				    (long long)((blk * DEV_BSIZE + i) /
@@ -378,19 +373,14 @@ bwrite(int fd, char *buf, daddr_t blk, long size)
 		return;
 	offset = blk;
 	offset *= DEV_BSIZE;
-	if (lseek(fd, offset, SEEK_SET) < 0)
-		rwerror("SEEK", blk);
-	else if (write(fd, buf, (int)size) == size) {
+	if (pwrite(fd, buf, size, offset) == size) {
 		fsmodified = 1;
 		return;
 	}
 	rwerror("WRITE", blk);
-	if (lseek(fd, offset, SEEK_SET) < 0)
-		rwerror("SEEK", blk);
 	printf("THE FOLLOWING SECTORS COULD NOT BE WRITTEN:");
 	for (cp = buf, i = 0; i < size; i += secsize, cp += secsize)
-		if (write(fd, cp, (int)secsize) != secsize) {
-			(void)lseek(fd, offset + i + secsize, SEEK_SET);
+		if (pwrite(fd, cp, secsize, offset + i) != secsize) {
 			if (secsize != DEV_BSIZE)
 				printf(" %lld (%lld),",
 				    (long long)((blk * DEV_BSIZE + i) /
diff --git a/sbin/ncheck_ffs/ncheck_ffs.c b/sbin/ncheck_ffs/ncheck_ffs.c
index b51717ee857..847fbea06c8 100644
--- a/sbin/ncheck_ffs/ncheck_ffs.c
+++ b/sbin/ncheck_ffs/ncheck_ffs.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ncheck_ffs.c,v 1.41 2014/05/13 05:50:24 guenther Exp $	*/
+/*	$OpenBSD: ncheck_ffs.c,v 1.42 2014/05/20 21:11:16 krw Exp $	*/
 
 /*-
  * Copyright (c) 1995, 1996 SigmaSoft, Th. Lockert <tholo@sigmasoft.com>
@@ -267,9 +267,8 @@ bread(daddr_t blkno, char *buf, int size)
 	int cnt, i;
 
 loop:
-	if (lseek(diskfd, ((off_t)blkno << dev_bshift), SEEK_SET) < 0)
-		warnx("bread: lseek fails");
-	if ((cnt = read(diskfd, buf, size)) == size)
+	if ((cnt = pread(diskfd, buf, size, (off_t)blkno << dev_bshift)) ==
+	    size)
 		return;
 	if (blkno + (size / dev_bsize) > fsbtodb(sblock, sblock->fs_ffs1_size)) {
 		/*
@@ -299,9 +298,8 @@ loop:
 	 */
 	memset(buf, 0, size);
 	for (i = 0; i < size; i += dev_bsize, buf += dev_bsize, blkno++) {
-		if (lseek(diskfd, ((off_t)blkno << dev_bshift), SEEK_SET) < 0)
-			warnx("bread: lseek2 fails!");
-		if ((cnt = read(diskfd, buf, (int)dev_bsize)) == dev_bsize)
+		if ((cnt = pread(diskfd, buf, (int)dev_bsize,
+			    (off_t)blkno << dev_bshift)) == dev_bsize)
 			continue;
 		if (cnt == -1) {
 			warnx("read error from %s: %s: [sector %lld]: "
diff --git a/sbin/quotacheck/quotacheck.c b/sbin/quotacheck/quotacheck.c
index 5530085434e..a74e7c9c07e 100644
--- a/sbin/quotacheck/quotacheck.c
+++ b/sbin/quotacheck/quotacheck.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: quotacheck.c,v 1.32 2014/05/12 21:10:35 krw Exp $	*/
+/*	$OpenBSD: quotacheck.c,v 1.33 2014/05/20 21:11:16 krw Exp $	*/
 /*	$NetBSD: quotacheck.c,v 1.12 1996/03/30 22:34:25 mark Exp $	*/
 
 /*
@@ -735,7 +735,6 @@ freeinodebuf(void)
 void
 bread(daddr_t bno, char *buf, long cnt)
 {
-	if (lseek(fi, (off_t)bno * DEV_BSIZE, SEEK_SET) < 0 ||
-	    read(fi, buf, cnt) != cnt)
-		err(1, "bread failed on block %lld", (long long)bno);
+	if (pread(fi, buf, cnt, bno * DEV_BSIZE) != cnt)
+		err(1, "read failed on block %lld", (long long)bno);
 }
diff --git a/sbin/tunefs/tunefs.c b/sbin/tunefs/tunefs.c
index 89cd7b85e48..68df1a8548c 100644
--- a/sbin/tunefs/tunefs.c
+++ b/sbin/tunefs/tunefs.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: tunefs.c,v 1.33 2014/05/12 12:16:53 krw Exp $	*/
+/*	$OpenBSD: tunefs.c,v 1.34 2014/05/20 21:11:16 krw Exp $	*/
 /*	$NetBSD: tunefs.c,v 1.33 2005/01/19 20:46:16 xtraeme Exp $	*/
 
 /*
@@ -292,26 +292,17 @@ getsb(struct fs *fs, const char *file)
 static void
 bwrite(daddr_t blk, char *buffer, int size, const char *file)
 {
-	off_t	offset;
-
-	offset = (off_t)blk * DEV_BSIZE;
-	if (lseek(fi, offset, SEEK_SET) == -1)
-		err(6, "%s: seeking to %lld", file, (long long)offset);
-	if (write(fi, buffer, size) != size)
-		err(7, "%s: writing %d bytes", file, size);
+	if (pwrite(fi, buffer, size, blk * DEV_BSIZE) != size)
+		err(7, "%s: writing %d bytes @ %lld", file, size,
+		    (long long)(blk * DEV_BSIZE));
 }
 
 static void
 bread(daddr_t blk, char *buffer, int cnt, const char *file)
 {
-	off_t	offset;
-	int	i;
-
-	offset = (off_t)blk * DEV_BSIZE;
-	if (lseek(fi, offset, SEEK_SET) == -1)
-		err(4, "%s: seeking to %lld", file, (long long)offset);
-	if ((i = read(fi, buffer, cnt)) != cnt)
-		errx(5, "%s: short read", file);
+	if ((pread(fi, buffer, cnt, (off_t)blk * DEV_BSIZE)) != cnt)
+		errx(5, "%s: reading %d bytes @ %lld", file, cnt,
+		    (long long)(blk * DEV_BSIZE));
 }
 
 static int