Attachment 7175 Details for Bug 8654 – Improve generation of hash file name

[patch] Improve generation of hash file name

0001-Improve-generation-of-hash-file-name.patch (text/plain), 1.62 KB, created by Chris Dunlop on 2011-12-13 02:48:36 UTC

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Creator: Chris Dunlop

Created: 2011-12-13 02:48:36 UTC

Size: 1.62 KB

patch

obsolete

>From 563f0e4115d0a7c22242d3f45ee2fdb365d82afc Mon Sep 17 00:00:00 2001
>From: Chris Dunlop <chris@onthe.net.au>
>Date: Tue, 13 Dec 2011 11:39:33 +1100
>Subject: [PATCH] Improve generation of hash file name
>
>Use the calculated checksum_len rather than assuming 16 bytes.
>
>Use assert() to check for buffer overflow
>
>Use sprintf() rather than hand-rolled binary-to-text. This is not in a
>critical performance path.
>
>Signed-off-by: Chris Dunlop <chris@onthe.net.au>
>---
> hashlink.c |   21 +++++++++------------
> 1 files changed, 9 insertions(+), 12 deletions(-)
>
>diff --git a/hashlink.c b/hashlink.c
>index 12cc39b..3f98beb 100644
>--- a/hashlink.c
>+++ b/hashlink.c
>@@ -21,27 +21,24 @@
> #include "rsync.h"
> 
> extern char *link_by_hash_dir;
>+extern int checksum_len;
> 
> #ifdef HAVE_LINK
> 
> char *make_hash_name(struct file_struct *file)
> {
>-	char hash[(MAX_DIGEST_LEN * 2) + 2], *dst;
>-	uchar c, *src = (uchar*)F_SUM(file);
>+	char hash[(MAX_DIGEST_LEN * 2) + 2], *dst = hash;
>+	uchar *src = (uchar*)F_SUM(file);
> 	int i;
> 
>-	for (dst = hash, i = 0; i < 4; i++, src++) {
>-		c = *src >> 4;
>-		*(dst++) = (c >= 10) ? (c - 10 + 'a') : (c + '0');
>-		c = *src & 0x0f;
>-		*(dst++) = (c >= 10) ? (c - 10 + 'a') : (c + '0');
>+	assert((uint)((checksum_len * 2) + 2) <= sizeof(hash));
>+
>+	for (i = 0; i < 4; i++) {
>+		dst += sprintf(dst, "%02x", (int)CVAL(src, i));
> 	}
> 	*dst++ = '/';
>-	for (i = 0; i < 12; i++, src++) {
>-		c = *src >> 4;
>-		*(dst++) = (c >= 10) ? (c - 10 + 'a') : (c + '0');
>-		c = *src & 0x0f;
>-		*(dst++) = (c >= 10) ? (c - 10 + 'a') : (c + '0');
>+	for ( ; i < checksum_len; i++) {
>+		dst += sprintf(dst, "%02x", (int)CVAL(src, i));
> 	}
> 	*dst = 0;
> 
>-- 
>1.7.0.4
>

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