[src/trunk]: src/bin/pax Use lseek(2) on devices if not tape drives.

[itohy <itohy%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/b86904684ddb
branches:  trunk
changeset: 482610:b86904684ddb
user:      itohy <itohy%NetBSD.org@localhost>
date:      Thu Feb 17 03:08:40 2000 +0000

description:
Use lseek(2) on devices if not tape drives.
This makes listing on raw disk device much faster.
Reviewed and discussed in tech-kern and tech-userlevel lists.

diffstat:

 bin/pax/ar_io.c |  19 +++++++++++--------
 1 files changed, 11 insertions(+), 8 deletions(-)

diffs (49 lines):

diff -r 41aee9954dcf -r b86904684ddb bin/pax/ar_io.c
--- a/bin/pax/ar_io.c   Thu Feb 17 03:06:12 2000 +0000
+++ b/bin/pax/ar_io.c   Thu Feb 17 03:08:40 2000 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: ar_io.c,v 1.15 2000/02/17 03:06:12 itohy Exp $ */
+/*     $NetBSD: ar_io.c,v 1.16 2000/02/17 03:08:40 itohy Exp $ */
 
 /*-
  * Copyright (c) 1992 Keith Muller.
@@ -42,7 +42,7 @@
 #if 0
 static char sccsid[] = "@(#)ar_io.c    8.2 (Berkeley) 4/18/94";
 #else
-__RCSID("$NetBSD: ar_io.c,v 1.15 2000/02/17 03:06:12 itohy Exp $");
+__RCSID("$NetBSD: ar_io.c,v 1.16 2000/02/17 03:08:40 itohy Exp $");
 #endif
 #endif /* not lint */
 
@@ -991,7 +991,7 @@
         * number of physical blocks to skip (we do not know physical block
         * size at this point), so we must only read foward on tapes!
         */
-       if (artyp != ISREG) 
+       if (artyp == ISTAPE || artyp == ISPIPE)
                return(0);
 
        /*
@@ -1004,13 +1004,16 @@
                 * deal with the end of file (it will go to next volume by
                 * itself)
                 */
-               if ((mpos = cpos + sksz) > arsb.st_size) {
-                       *skipped = arsb.st_size - cpos;
+               mpos = cpos + sksz;
+               if (artyp == ISREG && mpos > arsb.st_size)
                        mpos = arsb.st_size;
-               } else
-                       *skipped = sksz;
-               if (lseek(arfd, mpos, SEEK_SET) >= 0)
+               if ((mpos = lseek(arfd, mpos, SEEK_SET)) >= 0) {
+                       *skipped = mpos - cpos;
                        return(0);
+               }
+       } else {
+               if (artyp != ISREG)
+                       return(0);              /* non-seekable device */
        }
        syswarn(1, errno, "Foward positioning operation on archive failed");
        lstrval = -1;