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8387ff2577
We always mixed in the parent pointer into the dentry name hash, but we did it late at lookup time. It turns out that we can simplify that lookup-time action by salting the hash with the parent pointer early instead of late. A few other users of our string hashes also wanted to mix in their own pointers into the hash, and those are updated to use the same mechanism. Hash users that don't have any particular initial salt can just use the NULL pointer as a no-salt. Cc: Vegard Nossum <vegard.nossum@oracle.com> Cc: George Spelvin <linux@sciencehorizons.net> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
115 lines
3.7 KiB
C
115 lines
3.7 KiB
C
/*
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* linux/fs/hfs/string.c
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*
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* Copyright (C) 1995-1997 Paul H. Hargrove
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* (C) 2003 Ardis Technologies <roman@ardistech.com>
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* This file may be distributed under the terms of the GNU General Public License.
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*
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* This file contains the string comparison function for the
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* Macintosh character set.
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*
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* The code in this file is derived from code which is copyright
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* 1986, 1989, 1990 by Abacus Research and Development, Inc. (ARDI)
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* It is used here by the permission of ARDI's president Cliff Matthews.
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*/
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#include "hfs_fs.h"
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#include <linux/dcache.h>
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/*================ File-local variables ================*/
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/*
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* unsigned char caseorder[]
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*
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* Defines the lexical ordering of characters on the Macintosh
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*
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* Composition of the 'casefold' and 'order' tables from ARDI's code
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* with the entry for 0x20 changed to match that for 0xCA to remove
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* special case for those two characters.
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*/
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static unsigned char caseorder[256] = {
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0x00,0x01,0x02,0x03,0x04,0x05,0x06,0x07,0x08,0x09,0x0A,0x0B,0x0C,0x0D,0x0E,0x0F,
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0x10,0x11,0x12,0x13,0x14,0x15,0x16,0x17,0x18,0x19,0x1A,0x1B,0x1C,0x1D,0x1E,0x1F,
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0x20,0x22,0x23,0x28,0x29,0x2A,0x2B,0x2C,0x2F,0x30,0x31,0x32,0x33,0x34,0x35,0x36,
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0x37,0x38,0x39,0x3A,0x3B,0x3C,0x3D,0x3E,0x3F,0x40,0x41,0x42,0x43,0x44,0x45,0x46,
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0x47,0x48,0x57,0x59,0x5D,0x5F,0x66,0x68,0x6A,0x6C,0x72,0x74,0x76,0x78,0x7A,0x7E,
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0x8C,0x8E,0x90,0x92,0x95,0x97,0x9E,0xA0,0xA2,0xA4,0xA7,0xA9,0xAA,0xAB,0xAC,0xAD,
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0x4E,0x48,0x57,0x59,0x5D,0x5F,0x66,0x68,0x6A,0x6C,0x72,0x74,0x76,0x78,0x7A,0x7E,
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0x8C,0x8E,0x90,0x92,0x95,0x97,0x9E,0xA0,0xA2,0xA4,0xA7,0xAF,0xB0,0xB1,0xB2,0xB3,
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0x4A,0x4C,0x5A,0x60,0x7B,0x7F,0x98,0x4F,0x49,0x51,0x4A,0x4B,0x4C,0x5A,0x60,0x63,
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0x64,0x65,0x6E,0x6F,0x70,0x71,0x7B,0x84,0x85,0x86,0x7F,0x80,0x9A,0x9B,0x9C,0x98,
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0xB4,0xB5,0xB6,0xB7,0xB8,0xB9,0xBA,0x94,0xBB,0xBC,0xBD,0xBE,0xBF,0xC0,0x4D,0x81,
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0xC1,0xC2,0xC3,0xC4,0xC5,0xC6,0xC7,0xC8,0xC9,0xCA,0xCB,0x55,0x8A,0xCC,0x4D,0x81,
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0xCD,0xCE,0xCF,0xD0,0xD1,0xD2,0xD3,0x26,0x27,0xD4,0x20,0x49,0x4B,0x80,0x82,0x82,
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0xD5,0xD6,0x24,0x25,0x2D,0x2E,0xD7,0xD8,0xA6,0xD9,0xDA,0xDB,0xDC,0xDD,0xDE,0xDF,
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0xE0,0xE1,0xE2,0xE3,0xE4,0xE5,0xE6,0xE7,0xE8,0xE9,0xEA,0xEB,0xEC,0xED,0xEE,0xEF,
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0xF0,0xF1,0xF2,0xF3,0xF4,0xF5,0xF6,0xF7,0xF8,0xF9,0xFA,0xFB,0xFC,0xFD,0xFE,0xFF
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};
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/*================ Global functions ================*/
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/*
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* Hash a string to an integer in a case-independent way
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*/
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int hfs_hash_dentry(const struct dentry *dentry, struct qstr *this)
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{
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const unsigned char *name = this->name;
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unsigned int hash, len = this->len;
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if (len > HFS_NAMELEN)
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len = HFS_NAMELEN;
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hash = init_name_hash(dentry);
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for (; len; len--)
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hash = partial_name_hash(caseorder[*name++], hash);
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this->hash = end_name_hash(hash);
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return 0;
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}
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/*
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* Compare two strings in the HFS filename character ordering
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* Returns positive, negative, or zero, not just 0 or (+/-)1
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*
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* Equivalent to ARDI's call:
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* ROMlib_RelString(s1+1, s2+1, true, false, (s1[0]<<16) | s2[0])
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*/
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int hfs_strcmp(const unsigned char *s1, unsigned int len1,
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const unsigned char *s2, unsigned int len2)
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{
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int len, tmp;
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len = (len1 > len2) ? len2 : len1;
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while (len--) {
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tmp = (int)caseorder[*(s1++)] - (int)caseorder[*(s2++)];
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if (tmp)
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return tmp;
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}
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return len1 - len2;
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}
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/*
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* Test for equality of two strings in the HFS filename character ordering.
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* return 1 on failure and 0 on success
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*/
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int hfs_compare_dentry(const struct dentry *parent, const struct dentry *dentry,
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unsigned int len, const char *str, const struct qstr *name)
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{
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const unsigned char *n1, *n2;
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if (len >= HFS_NAMELEN) {
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if (name->len < HFS_NAMELEN)
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return 1;
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len = HFS_NAMELEN;
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} else if (len != name->len)
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return 1;
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n1 = str;
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n2 = name->name;
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while (len--) {
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if (caseorder[*n1++] != caseorder[*n2++])
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return 1;
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}
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return 0;
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}
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