From: Alex Elder <aelder@sgi.com>
To: xfs@oss.sgi.com
Subject: [PATCH 07/12] xfsprogs: use pointers in generate_obfuscated_name()
Date: Thu, 30 Dec 2010 14:41:23 -0600 [thread overview]
Message-ID: <1293741683.2294.366.camel@doink> (raw)
Switch from using array references to using pointers to
refer to the pathname characters as they get generated.
Also limit the scope of a few automatic variables.
Signed-off-by: Alex Elder <aelder@sgi.com>
---
db/metadump.c | 42 ++++++++++++++++++++++--------------------
1 file changed, 22 insertions(+), 20 deletions(-)
Index: b/db/metadump.c
===================================================================
--- a/db/metadump.c
+++ b/db/metadump.c
@@ -415,11 +415,8 @@ generate_obfuscated_name(
{
xfs_dahash_t hash;
name_ent_t *p;
- int i;
int dup;
- xfs_dahash_t newhash;
uchar_t newname[NAME_MAX];
- uchar_t *newp = &newname[0];
/*
* Our obfuscation algorithm requires at least 5-character
@@ -450,7 +447,12 @@ generate_obfuscated_name(
if (*name == '/')
name++;
do {
- uchar_t high_bit;
+ int i;
+ xfs_dahash_t newhash = 0;
+ uchar_t *newp = &newname[0];
+ uchar_t *first;
+ uchar_t high_bit;
+ int shift;
dup = 0;
@@ -460,10 +462,10 @@ generate_obfuscated_name(
* characters. Accumulate its new hash value as we
* go.
*/
- newhash = 0;
for (i = 0; i < namelen - 5; i++) {
- newp[i] = random_filename_char();
- newhash = newp[i] ^ rol32(newhash, 7);
+ *newp = random_filename_char();
+ newhash = *newp ^ rol32(newhash, 7);
+ newp++;
}
/*
@@ -478,16 +480,16 @@ generate_obfuscated_name(
*/
newhash = rol32(newhash, 3) ^ hash;
+ first = newp;
high_bit = 0;
- for (i = 5; i > 0; i--) {
- int shift = (i - 1) * 7;
-
- newp[namelen - i] = ((newhash >> shift) & 0x7f) ^ high_bit;
- if (is_invalid_char(newp[namelen - i])) {
- newp[namelen - i] ^= 1;
+ for (shift = 28; shift >= 0; shift -= 7) {
+ *newp = (newhash >> shift & 0x7f) ^ high_bit;
+ if (is_invalid_char(*newp)) {
+ *newp ^= 1;
high_bit = 0x80;
} else
high_bit = 0;
+ newp++;
}
/*
@@ -497,12 +499,12 @@ generate_obfuscated_name(
* we flip one more bit in both bytes.
*/
if (high_bit) {
- newp[namelen - 5] ^= 0x10;
- if (is_invalid_char(newp[namelen - 5])) {
- newp[namelen - 1] ^= 2;
- newp[namelen - 5] ^= 0x20;
- ASSERT(!is_invalid_char(newp[namelen - 1]));
- ASSERT(!is_invalid_char(newp[namelen - 5]));
+ *first ^= 0x10;
+ if (is_invalid_char(*first)) {
+ *--newp ^= 2;
+ *first ^= 0x20;
+ ASSERT(!is_invalid_char(*newp));
+ ASSERT(!is_invalid_char(*first));
}
}
@@ -510,7 +512,7 @@ generate_obfuscated_name(
for (p = nametable[hash % NAME_TABLE_SIZE]; p; p = p->next) {
if (p->hash == hash && p->namelen == namelen &&
- memcmp(p->name, newname, namelen) == 0){
+ !memcmp(p->name, newname, namelen)) {
dup = 1;
break;
}
_______________________________________________
xfs mailing list
xfs@oss.sgi.com
http://oss.sgi.com/mailman/listinfo/xfs
reply other threads:[~2010-12-30 20:39 UTC|newest]
Thread overview: [no followups] expand[flat|nested] mbox.gz Atom feed
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1293741683.2294.366.camel@doink \
--to=aelder@sgi.com \
--cc=xfs@oss.sgi.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox