From: Américo Wang <xiyou.wangcong@gmail.com>
Date: Thu, 26 Nov 2009 14:19:37 +0000 (+0800)
Subject: hexdump: bug in hexdump when offset == file length
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2c9f0e8e7f4c8049ecc259712c618ee75d94409d;p=util-linux

hexdump: bug in hexdump when offset == file length

On Thu, Nov 26, 2009 at 03:42:21AM -0500, Mike Smith wrote:
>[mike@laptop ~]$ dd if=/dev/urandom of=testfile bs=1 count=42
>42+0 records in
>42+0 records out
>42 bytes (42 B) copied, 0.000216179 s, 194 kB/s
>[mike@laptop ~]$ hexdump -Cv testfile -s 42
>0000002a  bb b0 ba 50 fe 70 f8 d9  f7 96 36 49 e9 74 c7 bd  |...P.p....6I.t..|
>0000003a  82 cb 19 64 a6 30 53 29  d2 fa 08 e3 f4 26 7f de  |...d.0S).....&..|
>0000004a  bb 2c f2 df 7c a7 8c 6e  66 01                    |.,..|..nf.|
>00000054
>[mike@laptop ~]$ hexdump -Cv testfile -s 43
>0000002a

I think I got where the bug is, it's an off-by-one problem...

Signed-off-by: WANG Cong <xiyou.wangcong@gmail.com>
---

diff --git a/text-utils/display.c b/text-utils/display.c
index 91857c2f..7a35e46f 100644
--- a/text-utils/display.c
+++ b/text-utils/display.c
@@ -336,7 +336,7 @@ doskip(const char *fname, int statok)
 			    fname, strerror(errno));
 			exit(1);
 		}
-		if (S_ISREG(sbuf.st_mode) && skip >= sbuf.st_size) {
+		if (S_ISREG(sbuf.st_mode) && skip > sbuf.st_size) {
 		  /* If size valid and skip >= size */
 			skip -= sbuf.st_size;
 			address += sbuf.st_size;