Unapply sessreg patch
19d392b8d7 committed the patched version
of this file.This commit is contained in:
Julien Cristau
parent
7ab21191d0
commit
6c663d055b
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@ -93,18 +93,6 @@ static void set_utmpx (struct utmpx *u, const char *line, const char *user,
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const char *host, Time_t date, int addp);
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#endif
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#ifdef SYSV
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/* used for hashing ut_id */
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typedef unsigned long int ub4; /* unsigned 4-byte quantities */
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typedef unsigned char ub1; /* unsigned 1-byte quantities */
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#define hashsize(n) ((ub4)1<<(n))
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#define hashmask(n) (hashsize(n)-1)
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ub4 hash(register ub1 *k, register ub4 length, register ub4 initval);
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#endif
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static int wflag, uflag, lflag;
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static char *wtmp_file, *utmp_file, *line;
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#ifdef USE_UTMPX
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@ -416,23 +404,21 @@ set_utmp (struct utmp *u, char *line, char *user, char *host, Time_t date, int a
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bzero (u->ut_name, sizeof (u->ut_name));
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#ifdef SYSV
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if (line) {
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int i;
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/*
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* The ut_id is 4 bytes long. We make a hash of the line
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* received, preceding it by ":" to prevent clashing with
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* other ut_ids.
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* this is a bit crufty, but
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* follows the apparent conventions in
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* the ttys file. ut_id is only 4 bytes
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* long, and the last 4 bytes of the line
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* name are written into it, left justified.
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*/
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ub4 h;
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u->ut_id[0]=':';
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h = hash(line, strlen(line),0x9e3779b9);
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h = (h & hashmask((sizeof(u->ut_id)-sizeof(char))*8));
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(void) strncpy (u->ut_id + 1,(char *) &h, sizeof (u->ut_id)-sizeof(char));
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i = strlen (line);
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if (i >= sizeof (u->ut_id))
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i -= sizeof (u->ut_id);
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else
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i = 0;
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(void) strncpy (u->ut_id, line + i, sizeof (u->ut_id));
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} else
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/*
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* From utmp(5):
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* Clearing ut_id may result in race conditions leading to corrupted
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* utmp entries and and potential security holes.
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*/
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/* TODO: CHECK this */
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bzero (u->ut_id, sizeof (u->ut_id));
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if (addp) {
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u->ut_pid = getppid ();
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@ -676,129 +662,3 @@ findslot (char *line_name, char *host_name, int addp, int slot)
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return freeslot;
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}
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#endif
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#ifdef SYSV
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/*
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--------------------------------------------------------------------
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mix -- mix 3 32-bit values reversibly.
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For every delta with one or two bits set, and the deltas of all three
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high bits or all three low bits, whether the original value of a,b,c
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is almost all zero or is uniformly distributed,
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* If mix() is run forward or backward, at least 32 bits in a,b,c
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have at least 1/4 probability of changing.
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* If mix() is run forward, every bit of c will change between 1/3 and
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2/3 of the time. (Well, 22/100 and 78/100 for some 2-bit deltas.)
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mix() was built out of 36 single-cycle latency instructions in a
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structure that could supported 2x parallelism, like so:
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a -= b;
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a -= c; x = (c>>13);
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b -= c; a ^= x;
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b -= a; x = (a<<8);
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c -= a; b ^= x;
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c -= b; x = (b>>13);
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...
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Unfortunately, superscalar Pentiums and Sparcs can't take advantage
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of that parallelism. They've also turned some of those single-cycle
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latency instructions into multi-cycle latency instructions. Still,
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this is the fastest good hash I could find. There were about 2^^68
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to choose from. I only looked at a billion or so.
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--------------------------------------------------------------------
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*/
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#define mix(a,b,c) \
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{ \
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a -= b; a -= c; a ^= (c>>13); \
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b -= c; b -= a; b ^= (a<<8); \
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c -= a; c -= b; c ^= (b>>13); \
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a -= b; a -= c; a ^= (c>>12); \
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b -= c; b -= a; b ^= (a<<16); \
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c -= a; c -= b; c ^= (b>>5); \
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a -= b; a -= c; a ^= (c>>3); \
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b -= c; b -= a; b ^= (a<<10); \
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c -= a; c -= b; c ^= (b>>15); \
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}
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/*
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--------------------------------------------------------------------
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hash() -- hash a variable-length key into a 32-bit value
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k : the key (the unaligned variable-length array of bytes)
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len : the length of the key, counting by bytes
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initval : can be any 4-byte value
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Returns a 32-bit value. Every bit of the key affects every bit of
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the return value. Every 1-bit and 2-bit delta achieves avalanche.
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About 6*len+35 instructions.
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The best hash table sizes are powers of 2. There is no need to do
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mod a prime (mod is sooo slow!). If you need less than 32 bits,
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use a bitmask. For example, if you need only 10 bits, do
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h = (h & hashmask(10));
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In which case, the hash table should have hashsize(10) elements.
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If you are hashing n strings (ub1 **)k, do it like this:
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for (i=0, h=0; i<n; ++i) h = hash( k[i], len[i], h);
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By Bob Jenkins, 1996. bob_jenkins@burtleburtle.net. You may use this
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code any way you wish, private, educational, or commercial. It's free.
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[On 27 May 2004, Bob Jenkins further clarified the above statement.
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From: Bob Jenkins <bob_jenkins@burtleburtle.net>
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Date: Thu, 27 May 2004 22:33:06 -0700
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To: Margarita Manterola <marga@marga.com.ar>
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Subject: Re: Hash function
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The algorithm is public domain. I ask that I be referenced as the
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source of the algorithm, but I can't enforce that, since being public
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domain means I've reserved no rights at all.
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-- Branden Robinson, 2004-06-06]
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See http://burtleburtle.net/bob/hash/evahash.html
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Use for hash table lookup, or anything where one collision in 2^^32 is
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acceptable. Do NOT use for cryptographic purposes.
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--------------------------------------------------------------------
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*/
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ub4
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hash(register ub1 *k, register ub4 length, register ub4 initval)
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{
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register ub4 a,b,c,len;
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/* Set up the internal state */
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len = length;
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a = b = 0x9e3779b9; /* the golden ratio; an arbitrary value */
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c = initval; /* the previous hash value */
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/*---------------------------------------- handle most of the key */
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while (len >= 12)
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{
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a += (k[0] +((ub4)k[1]<<8) +((ub4)k[2]<<16) +((ub4)k[3]<<24));
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b += (k[4] +((ub4)k[5]<<8) +((ub4)k[6]<<16) +((ub4)k[7]<<24));
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c += (k[8] +((ub4)k[9]<<8) +((ub4)k[10]<<16)+((ub4)k[11]<<24));
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mix(a,b,c);
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k += 12; len -= 12;
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}
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/*------------------------------------- handle the last 11 bytes */
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c += length;
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switch(len) /* all the case statements fall through */
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{
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case 11: c+=((ub4)k[10]<<24);
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case 10: c+=((ub4)k[9]<<16);
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case 9 : c+=((ub4)k[8]<<8);
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/* the first byte of c is reserved for the length */
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case 8 : b+=((ub4)k[7]<<24);
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case 7 : b+=((ub4)k[6]<<16);
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case 6 : b+=((ub4)k[5]<<8);
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case 5 : b+=k[4];
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case 4 : a+=((ub4)k[3]<<24);
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case 3 : a+=((ub4)k[2]<<16);
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case 2 : a+=((ub4)k[1]<<8);
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case 1 : a+=k[0];
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/* case 0: nothing left to add */
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}
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mix(a,b,c);
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/*-------------------------------------------- report the result */
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return c;
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}
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#endif
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