From mboxrd@z Thu Jan  1 00:00:00 1970
Date: Sun,  7 Apr 1996 00:49:30 -0500
From: scott@angora.cse.psu.edu scott@angora.cse.psu.edu
Subject: No subject
Topicbox-Message-UUID: 42723bb2-eac8-11e9-9e20-41e7f4b1d025
Message-ID: <19960407054930.Ka3fH8PXAkw58nHZ6LSqbCQkaZTBiDlvKNf0JtWRMDU@z>

tarfs reports checksum errors on some tarfiles (generated by gnutar, I think),
because it computes the checksum over all TBLOCK chars, but only reads the
header before doing so.  The following patch seems to fix the problem.

term% diff /n/cd/sys/src/cmd/tapefs/tarfs.c .
38c38
< 	long blkno, isabs, chksum, linkflg;
---
> 	long blkno, isabs, chksum, linkflg, t;
47c47
< 		if (read(tapefile, (char *)&dblock.dbuf, sizeof(dblock.dbuf))<sizeof(dblock.dbuf))
---
> 		if (read(tapefile, (char *)&dblock, sizeof(dblock))<sizeof(dblock))
60,61c60,61
< 		if (chksum != checksum()){
< 			fprint(1, "bad checksum on %.28s\n", dblock.dbuf.name);
---
> 		if (chksum != (t=checksum())){
> 			fprint(1, "bad checksum %o != %o on %.28s\n", chksum, t, dblock.dbuf.name);
132c132
< 		i += *cp;
---
> 		i += *cp & 0xff;