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freebsd-dev/contrib/tcsh/sh.hist.c
Brooks Davis d803a9d0e5 Update tcsh to git revision 83c5be0 bringing in a number of bug fixes. 
Reported by:	sobomax
MFC after:	3 days
Sponsored by:	DARPA, AFRL
Differential Revision:	https://reviews.freebsd.org/D22099
2019-10-21 21:21:34 +00:00

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/*
* sh.hist.c: Shell history expansions and substitutions
*/
/*-
* Copyright (c) 1980, 1991 The Regents of the University of California.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include "sh.h"
#include <stdio.h> /* for rename(2), grr. */
#include <assert.h>
#include "tc.h"
#include "dotlock.h"
extern int histvalid;
extern struct Strbuf histline;
Char HistLit = 0;
static int heq (const struct wordent *, const struct wordent *);
static void hfree (struct Hist *);
#define HIST_ONLY 0x01
#define HIST_SAVE 0x02
#define HIST_LOAD 0x04
#define HIST_REV 0x08
#define HIST_CLEAR 0x10
#define HIST_MERGE 0x20
#define HIST_TIME 0x40
/*
* C shell
*/
/* Static functions don't show up in gprof summaries. So eliminate "static"
* modifier from some frequently called functions. */
#ifdef PROF
#define PG_STATIC
#else
#define PG_STATIC static
#endif
/* #define DEBUG_HIST 1 */
static const int fastMergeErase = 1;
static unsigned histCount = 0; /* number elements on history list */
static int histlen = 0;
static struct Hist *histTail = NULL; /* last element on history list */
static struct Hist *histMerg = NULL; /* last element merged by Htime */
static void insertHistHashTable(struct Hist *, unsigned);
/* Insert new element (hp) in history list after specified predecessor (pp). */
static void
hinsert(struct Hist *hp, struct Hist *pp)
{
struct Hist *fp = pp->Hnext; /* following element, if any */
hp->Hnext = fp, hp->Hprev = pp;
pp->Hnext = hp;
if (fp)
fp->Hprev = hp;
else
histTail = hp; /* meaning hp->Hnext == NULL */
histCount++;
}
/* Remove the entry from the history list. */
static void
hremove(struct Hist *hp)
{
struct Hist *pp = hp->Hprev;
assert(pp); /* elements always have a previous */
pp->Hnext = hp->Hnext;
if (hp->Hnext)
hp->Hnext->Hprev = pp;
else
histTail = pp; /* we must have been last */
if (hp == histMerg) /* deleting this hint from list */
histMerg = NULL;
assert(histCount > 0);
histCount--;
}
/* Prune length of history list to specified size by history variable. */
PG_STATIC void
discardExcess(int hlen)
{
struct Hist *hp, *np;
if (histTail == NULL) {
assert(histCount == 0);
return; /* no entries on history list */
}
/* Prune dummy entries from the front, then old entries from the back. If
* the list is still too long scan the whole list as before. But only do a
* full scan if the list is more than 6% (1/16th) too long. */
while (histCount > (unsigned)hlen && (np = Histlist.Hnext)) {
if (eventno - np->Href >= hlen || hlen == 0)
hremove(np), hfree(np);
else
break;
}
while (histCount > (unsigned)hlen && (np = histTail) != &Histlist) {
if (eventno - np->Href >= hlen || hlen == 0)
hremove(np), hfree(np);
else
break;
}
if (histCount - (hlen >> 4) <= (unsigned)hlen)
return; /* don't bother doing the full scan */
for (hp = &Histlist; histCount > (unsigned)hlen &&
(np = hp->Hnext) != NULL;)
if (eventno - np->Href >= hlen || hlen == 0)
hremove(np), hfree(np);
else
hp = np;
}
/* Add the command "sp" to the history list. */
void
savehist(
struct wordent *sp,
int mflg) /* true if -m (merge) specified */
{
/* throw away null lines */
if (sp && sp->next->word[0] == '\n')
return;
if (sp)
(void) enthist(++eventno, sp, 1, mflg, histlen);
discardExcess(histlen);
}
#define USE_JENKINS_HASH 1
/* #define USE_ONE_AT_A_TIME 1 */
#undef PRIME_LENGTH /* no need for good HTL */
#ifdef USE_JENKINS_HASH
#define hashFcnName "lookup3"
/* From:
lookup3.c, by Bob Jenkins, May 2006, Public Domain.
"... You can use this free for any purpose. It's in
the public domain. It has no warranty."
http://burtleburtle.net/bob/hash/index.html
*/
#define rot(x,k) (((x)<<(k)) | ((x)>>(32-(k))))
#define mix(a,b,c) \
{ \
a -= c; a ^= rot(c, 4); c += b; \
b -= a; b ^= rot(a, 6); a += c; \
c -= b; c ^= rot(b, 8); b += a; \
a -= c; a ^= rot(c,16); c += b; \
b -= a; b ^= rot(a,19); a += c; \
c -= b; c ^= rot(b, 4); b += a; \
}
#define final(a,b,c) \
{ \
c ^= b; c -= rot(b,14); \
a ^= c; a -= rot(c,11); \
b ^= a; b -= rot(a,25); \
c ^= b; c -= rot(b,16); \
a ^= c; a -= rot(c, 4); \
b ^= a; b -= rot(a,14); \
c ^= b; c -= rot(b,24); \
}
struct hashValue /* State used to hash a wordend word list. */
{
uint32_t a, b, c;
};
/* Set up the internal state */
static void
initializeHash(struct hashValue *h)
{
h->a = h->b = h->c = 0xdeadbeef;
}
/* This does a partial hash of the Chars in a single word. For efficiency we
* include 3 versions of the code to pack Chars into 32-bit words for the
* mixing function. */
static void
addWordToHash(struct hashValue *h, const Char *word)
{
uint32_t a = h->a, b = h->b, c = h->c;
#ifdef SHORT_STRINGS
#ifdef WIDE_STRINGS
assert(sizeof(Char) >= 4);
while (1) {
unsigned k;
if ((k = (uChar)*word++) == 0) break; a += k;
if ((k = (uChar)*word++) == 0) break; b += k;
if ((k = (uChar)*word++) == 0) break; c += k;
mix(a, b, c);
}
#else
assert(sizeof(Char) == 2);
while (1) {
unsigned k;
if ((k = (uChar)*word++) == 0) break; a += k;
if ((k = (uChar)*word++) == 0) break; a += k << 16;
if ((k = (uChar)*word++) == 0) break; b += k;
if ((k = (uChar)*word++) == 0) break; b += k << 16;
if ((k = (uChar)*word++) == 0) break; c += k;
if ((k = (uChar)*word++) == 0) break; c += k << 16;
mix(a, b, c);
}
#endif
#else
assert(sizeof(Char) == 1);
while (1) {
unsigned k;
if ((k = *word++) == 0) break; a += k;
if ((k = *word++) == 0) break; a += k << 8;
if ((k = *word++) == 0) break; a += k << 16;
if ((k = *word++) == 0) break; a += k << 24;
if ((k = *word++) == 0) break; b += k;
if ((k = *word++) == 0) break; b += k << 8;
if ((k = *word++) == 0) break; b += k << 16;
if ((k = *word++) == 0) break; b += k << 24;
if ((k = *word++) == 0) break; c += k;
if ((k = *word++) == 0) break; c += k << 8;
if ((k = *word++) == 0) break; c += k << 16;
if ((k = *word++) == 0) break; c += k << 24;
mix(a, b, c);
}
#endif
h->a = a, h->b = b, h->c = c;
}
static void
addCharToHash(struct hashValue *h, Char ch)
{
/* The compiler (gcc -O2) seems to do a good job optimizing this without
* explicitly extracting into local variables. */
h->a += (uChar)ch;
mix(h->a, h->b, h->c);
}
static uint32_t
finalizeHash(struct hashValue *h)
{
uint32_t a = h->a, b = h->b, c = h->c;
final(a, b, c);
return c;
}
#elif USE_ONE_AT_A_TIME
#define hashFcnName "one-at-a-time"
/* This one is also from Bob Jenkins, but is slower but simpler than lookup3.
"... The code given here are all public domain."
http://burtleburtle.net/bob/hash/doobs.html */
#if 0
ub4
one_at_a_time(char *key, ub4 len)
{
ub4 hash, i;
for (hash=0, i=0; i<len; ++i)
{
hash += key[i];
hash += (hash << 10);
hash ^= (hash >> 6);
}
hash += (hash << 3);
hash ^= (hash >> 11);
hash += (hash << 15);
return (hash & mask);
}
#endif
struct hashValue { uint32_t h; };
static void
initializeHash(struct hashValue *h)
{
h->h = 0;
}
static void
addWordToHash(struct hashValue *h, const Char *word)
{
unsigned k;
uint32_t hash = h->h;
while (k = (uChar)*word++)
hash += k, hash += hash << 10, hash ^= hash >> 6;
h->h = hash;
}
static void
addCharToHash(struct hashValue *h, Char c)
{
Char b[2] = { c, 0 };
addWordToHash(h, b);
}
static uint32_t
finalizeHash(struct hashValue *h)
{
unsigned hash = h->h;
hash += (hash << 3);
hash ^= (hash >> 11);
hash += (hash << 15);
return hash;
}
#else
#define hashFcnName "add-mul"
/* Simple multipy and add hash. */
#define PRIME_LENGTH 1 /* need "good" HTL */
struct hashValue { uint32_t h; };
static void
initializeHash(struct hashValue *h)
{
h->h = 0xe13e2345;
}
static void
addWordToHash(struct hashValue *h, const Char *word)
{
unsigned k;
uint32_t hash = h->h;
while (k = (uChar)*word++)
hash = hash * 0x9e4167b9 + k;
h->h = hash;
}
static void
addCharToHash(struct hashValue *h, Char c)
{
h->h = h->h * 0x9e4167b9 + (uChar)c;
}
static uint32_t
finalizeHash(struct hashValue *h)
{
return h->h;
}
#endif
static unsigned
hashhist(struct wordent *h0)
{
struct hashValue s;
struct wordent *firstWord = h0->next;
struct wordent *h = firstWord;
unsigned hash = 0;
initializeHash(&s);
for (; h != h0; h = h->next) {
if (h->word[0] == '\n')
break; /* don't hash newline */
if (h != firstWord)
addCharToHash(&s, ' '); /* space between words */
addWordToHash(&s, h->word);
}
hash = finalizeHash(&s);
/* Zero means no hash value, so never return zero as a hash value. */
return hash ? hash : 0x7fffffff; /* prime! */
}
#if 0
unsigned
hashStr(Char *str)
{
struct hashValue s;
initializeHash(&s);
addWordToHash(&s, str);
return finalizeHash(&s);
}
#endif
#ifdef PRIME_LENGTH /* need good HTL */
#define hash2tableIndex(hash, len) ((hash) % len)
#else
#define hash2tableIndex(hash, len) ((hash) & (len-1))
#endif
/* This code can be enabled to test the above hash functions for speed and
* collision avoidance. The testing is enabled by "occasional" calls to
* displayHistStats(), see which. */
#ifdef DEBUG_HIST
#ifdef BSDTIMES
static double
doTiming(int start) {
static struct timeval beginTime;
if (start) {
gettimeofday(&beginTime, NULL);
return 0.0;
} else {
struct timeval now;
gettimeofday(&now, NULL);
return (now.tv_sec-beginTime.tv_sec) +
(now.tv_usec-beginTime.tv_usec)/1e6;
}
}
#else
static double
doTiming(int start) {
USE(start);
return 0.0;
}
#endif
static void
generateHashes(int nChars, unsigned nWords, unsigned samples, unsigned *hashes,
unsigned length)
{
if (nChars < 1)
return;
nWords = (nWords < 1) ? 1 : (nWords > 4) ? 4 : nWords;
Char *number = xmalloc((nChars+nWords)*sizeof(Char));
struct wordent word[4];
struct wordent base = { NULL, &word[0], &word[0] };
word[0].word = number, word[0].next = &base, word[0].prev = &base;
unsigned w = 0; /* word number */
/* Generate multiple words of length 2, 3, 5, then all the rest. */
unsigned wBoundaries[4] = { 2-1, 2+3-1, 2+3+5-1, 0 };
/* Ensure the last word has at least 4 Chars in it. */
while (nWords >= 2 && nChars < (wBoundaries[nWords-2]+1) + 4)
nWords--;
wBoundaries[nWords-1] = 0xffffffff; /* don't end word past this point */
unsigned i;
for (i = 0; i<nChars; i++) {
/* In deference to the gawd awful add-mul hash, we won't use the worse
* case here (setting all Chars to 1), but assume mostly (or at least
* initially) ASCII data. */
number[i+w] = '!'; /* 0x21 = 33 */
if (i == wBoundaries[w]) { /* end a word here and move to next */
w++; /* next word */
number[i+w] = 0; /* terminate */
word[w].word = &number[i+w+1];
word[w].next = &base, word[w].prev = &word[w-1];
word[w-1].next = &word[w], base.prev = &word[w];
}
}
/* w is the index of the last word actually created. */
number[nChars + w] = 0; /* terminate last word */
unsigned timeLimit = !samples;
if (samples == 0)
samples = 1000000000;
doTiming(1);
double sec;
for (i = 0; i < samples; i++) {
/* increment 4 digit base 255 number; last characters vary fastest */
unsigned j = nChars-1 + w;
while (1) {
if (++number[j] != 0)
break;
/* else reset this digit and proceed to next one */
number[j] = 1;
if (&number[j] <= word[w].word)
break; /* stop at beginning of last word */
j--;
}
if (word[w].word[0] == '\n')
word[w].word[0]++; /* suppress newline character */
unsigned hash = hashhist(&base);
hashes[hash2tableIndex(hash, length)]++;
if (timeLimit && (i & 0x3ffff) == 0x3ffff) {
sec = doTiming(0);
if (sec > 10)
break;
}
}
if (i >= samples)
sec = doTiming(0);
else
samples = i; /* number we actually did */
if (sec > 0.01) {
xprintf("Hash %d (%d Char %u words) with %s: %d nsec/hash, %d mcps\n",
samples, nChars, w+1, hashFcnName, (int)((sec/samples)*1e9),
(int)((double)samples*nChars/sec/1e6));
}
}
#endif /* DEBUG_HIST */
#ifdef DEBUG_HIST
static void
testHash(void)
{
static const Char STRtestHashTimings[] =
{ 't','e','s','t','H','a','s','h','T','i','m','i','n','g','s', 0 };
struct varent *vp = adrof(STRtestHashTimings);
if (vp && vp->vec) {
unsigned hashes[4]; /* dummy place to put hashes */
Char **vals = vp->vec;
while (*vals) {
int length = getn(*vals);
unsigned words =
(length < 5) ? 1 : (length < 25) ? 2 : (length < 75) ? 3 : 4;
if (length > 0)
generateHashes(length, words, 0, hashes, 4);
vals++;
}
}
unsigned length = 1024;
#ifdef PRIME_LENGTH /* need good HTL */
length = 1021;
#endif
unsigned *hashes = xmalloc(length*sizeof(unsigned));
memset(hashes, 0, length*sizeof(unsigned));
/* Compute collision statistics for half full hashes modulo "length". */
generateHashes(4, 1, length/2, hashes, length);
/* Evaluate collisions by comparing occupancy rates (mean value 0.5).
* One bin for each number of hits. */
unsigned bins[155];
memset(bins, 0, sizeof(bins));
unsigned highest = 0;
unsigned i;
for (i = 0; i<length; i++) {
unsigned hits = hashes[i];
if (hits >= sizeof(bins)/sizeof(bins[0])) /* clip */
hits = highest = sizeof(bins)/sizeof(bins[0]) - 1;
if (hits > highest)
highest = hits;
bins[hits]++;
}
xprintf("Occupancy of %d buckets by %d hashes %d Chars %d word with %s\n",
length, length/2, 4, 1, hashFcnName);
for (i = 0; i <= highest; i++) {
xprintf(" %d buckets (%d%%) with %d hits\n",
bins[i], bins[i]*100/length, i);
}
/* Count run lengths to evaluate linear rehashing effectiveness. Estimate
* a little corrupted by edge effects. */
memset(bins, 0, sizeof(bins));
highest = 0;
for (i = 0; hashes[i] == 0; i++); /* find first occupied bucket */
unsigned run = 0;
unsigned rehashed = 0;
for (; i<length; i++) {
unsigned hits = hashes[i];
if (hits == 0 && rehashed > 0)
hits = 1 && rehashed--;
else if (hits > 1)
rehashed += hits-1;
if (hits)
run++;
else {
/* a real free slot, count it */
if (run >= sizeof(bins)/sizeof(bins[0])) /* clip */
run = highest = sizeof(bins)/sizeof(bins[0]) - 1;
if (run > highest)
highest = run;
bins[run]++;
run = 0;
}
}
/* Ignore the partial run at end as we ignored the beginning. */
double merit = 0.0, entries = 0;
for (i = 0; i <= highest; i++) {
entries += bins[i]*i; /* total hashed objects */
merit += bins[i]*i*i;
}
xprintf("Rehash collision figure of merit %u (ideal=100), run lengths:\n",
(int)(100.0*merit/entries));
for (i = 0; i <= highest; i++) {
if (bins[i] != 0)
xprintf(" %d runs of length %d buckets\n", bins[i], i);
}
xfree(hashes);
}
#endif /* DEBUG_HIST */
/* Compares two word lists for equality. */
static int
heq(const struct wordent *a0, const struct wordent *b0)
{
const struct wordent *a = a0->next, *b = b0->next;
for (;;) {
if (Strcmp(a->word, b->word) != 0)
return 0;
a = a->next;
b = b->next;
if (a == a0)
return (b == b0) ? 1 : 0;
if (b == b0)
return 0;
}
}
/* Renumber entries following p, which we will be deleting. */
PG_STATIC void
renumberHist(struct Hist *p)
{
int n = p->Href;
while ((p = p->Hnext))
p->Href = n--;
}
/* The hash table is implemented as an array of pointers to Hist entries. Each
* entry is located in the table using hash2tableIndex() and checking the
* following entries in case of a collision (linear rehash). Free entries in
* the table are zero (0, NULL, emptyHTE). Deleted entries that cannot yet be
* freed are set to one (deletedHTE). The Hist.Hhash member is non-zero iff
* the entry is in the hash table. When the hash table get too full, it is
* reallocated to be approximately twice the history length (see
* getHashTableSize). */
static struct Hist **histHashTable = NULL;
static unsigned histHashTableLength = 0; /* number of Hist pointers in table */
static struct Hist * const emptyHTE = NULL;
static struct Hist * const deletedHTE = (struct Hist *)1;
static struct {
unsigned insertCount;
unsigned removeCount;
unsigned rehashes;
int deleted;
} hashStats;
#ifdef DEBUG_HIST
void
checkHistHashTable(int print)
{
unsigned occupied = 0;
unsigned deleted = 0;
unsigned i;
for (i = 0; i<histHashTableLength; i++)
if (histHashTable[i] == emptyHTE)
continue;
else if (histHashTable[i] == deletedHTE)
deleted++;
else
occupied++;
if (print)
xprintf(" found len %u occupied %u deleted %u\n",
histHashTableLength, occupied, deleted);
assert(deleted == hashStats.deleted);
}
static int doneTest = 0;
/* Main entry point for displaying history statistics and hash function
* behavior. */
void
displayHistStats(const char *reason)
{
/* Just hash statistics for now. */
xprintf("%s history hash table len %u count %u (deleted %d)\n", reason,
histHashTableLength, histCount, hashStats.deleted);
xprintf(" inserts %u rehashes %u%% each\n",
hashStats.insertCount,
(hashStats.insertCount
? 100*hashStats.rehashes/hashStats.insertCount : 0));
xprintf(" removes %u net %u\n",
hashStats.removeCount,
hashStats.insertCount - hashStats.removeCount);
assert(hashStats.insertCount >= hashStats.removeCount);
checkHistHashTable(1);
memset(&hashStats, 0, sizeof(hashStats));
if (!doneTest) {
testHash();
doneTest = 1;
}
}
#else
void
displayHistStats(const char *reason)
{
USE(reason);
}
#endif
static void
discardHistHashTable(void)
{
if (histHashTable == NULL)
return;
displayHistStats("Discarding");
xfree(histHashTable);
histHashTable = NULL;
}
/* Computes a new hash table size, when the current one is too small. */
static unsigned
getHashTableSize(int hlen)
{
unsigned target = hlen * 2;
unsigned e = 5;
unsigned size;
while ((size = 1<<e) < target)
e++;
#ifdef PRIME_LENGTH /* need good HTL */
/* Not all prime, but most are and none have factors smaller than 11. */
return size+15;
#else
assert((size & (size-1)) == 0); /* must be a power of two */
return size;
#endif
}
/* Create the hash table or resize, if necessary. */
static void
createHistHashTable(int hlen)
{
if (hlen == 0) {
discardHistHashTable();
return;
}
if (hlen < 0) {
if (histlen <= 0)
return; /* no need for hash table */
hlen = histlen;
}
if (histHashTable != NULL) {
if (histCount < histHashTableLength * 3 / 4)
return; /* good enough for now */
discardHistHashTable(); /* too small */
}
histHashTableLength = getHashTableSize(
hlen > (int)histCount ? hlen : (int)histCount);
histHashTable = xmalloc(histHashTableLength * sizeof(struct Hist *));
memset(histHashTable, 0, histHashTableLength * sizeof(struct Hist *));
assert(histHashTable[0] == emptyHTE);
/* Now insert all the entries on the history list into the hash table. */
{
struct Hist *hp;
for (hp = &Histlist; (hp = hp->Hnext) != NULL;) {
unsigned lpHash = hashhist(&hp->Hlex);
assert(!hp->Hhash || hp->Hhash == lpHash);
hp->Hhash = 0; /* force insert to new hash table */
insertHistHashTable(hp, lpHash);
}
}
}
/* Insert np into the hash table. We assume that np is already on the
* Histlist. The specified hashval matches the new Hist entry but has not yet
* been assigned to Hhash (or the element is already on the hash table). */
static void
insertHistHashTable(struct Hist *np, unsigned hashval)
{
unsigned rehashes = 0;
unsigned hi = 0;
if (!histHashTable)
return;
if (np->Hhash != 0) {
/* already in hash table */
assert(hashval == np->Hhash);
return;
}
assert(np != deletedHTE);
/* Find a free (empty or deleted) slot, using linear rehash. */
assert(histHashTable);
for (rehashes = 0;
((hi = hash2tableIndex(hashval + rehashes, histHashTableLength)),
histHashTable[hi] != emptyHTE && histHashTable[hi] != deletedHTE);
rehashes++) {
assert(np != histHashTable[hi]);
if (rehashes >= histHashTableLength / 10) {
/* Hash table is full, so grow it. We assume the create function
* will roughly double the size we give it. Create initializes the
* new table with everything on the Histlist, so we are done when
* it returns. */
#ifdef DEBUG_HIST
xprintf("Growing history hash table from %d ...",
histHashTableLength);
flush();
#endif
discardHistHashTable();
createHistHashTable(histHashTableLength);
#ifdef DEBUG_HIST
xprintf("to %d.\n", histHashTableLength);
#endif
return;
}
}
/* Might be sensible to grow hash table if rehashes is "too big" here. */
if (histHashTable[hi] == deletedHTE)
hashStats.deleted--;
histHashTable[hi] = np;
np->Hhash = hashval;
hashStats.insertCount++;
hashStats.rehashes += rehashes;
}
/* Remove the 'np' entry from the hash table. */
static void
removeHistHashTable(struct Hist *np)
{
unsigned hi = np->Hhash;
if (!histHashTable || !hi)
return; /* no hash table or not on it */
/* find desired entry */
while ((hi = hash2tableIndex(hi, histHashTableLength)),
histHashTable[hi] != emptyHTE) {
if (np == histHashTable[hi]) {
unsigned i;
unsigned deletes = 0;
histHashTable[hi] = deletedHTE; /* dummy, but non-zero entry */
/* now peek ahead to see if the dummies are really necessary. */
i = 1;
while (histHashTable[hash2tableIndex(hi+i, histHashTableLength)] ==
deletedHTE)
i++;
if (histHashTable[hash2tableIndex(hi+i, histHashTableLength)] ==
emptyHTE) {
/* dummies are no longer necessary placeholders. */
deletes = i;
while (i-- > 0) {
histHashTable[hash2tableIndex(hi+i, histHashTableLength)] =
emptyHTE;
}
}
hashStats.deleted += 1 - deletes; /* delta deleted entries */
hashStats.removeCount++;
return;
}
hi++; /* linear rehash */
}
assert(!"Hist entry not found in hash table");
}
/* Search the history hash table for a command matching lp, using hashval as
* its hash value. */
static struct Hist *
findHistHashTable(struct wordent *lp, unsigned hashval)
{
unsigned deleted = 0; /* number of deleted entries skipped */
unsigned hi = hashval;
struct Hist *hp;
if (!histHashTable)
return NULL;
while ((hi = hash2tableIndex(hi, histHashTableLength)),
(hp = histHashTable[hi]) != emptyHTE) {
if (hp == deletedHTE)
deleted++;
else if (hp->Hhash == hashval && heq(lp, &(hp->Hlex)))
return hp;
if (deleted > (histHashTableLength>>4)) {
/* lots of deletes, so we need a sparser table. */
discardHistHashTable();
createHistHashTable(histHashTableLength);
return findHistHashTable(lp, hashval);
}
hi++; /* linear rehash */
}
return NULL;
}
/* When merge semantics are in use, find the approximate predecessor for the
* new entry, so that the Htime entries are decreasing. Return the entry just
* before the first entry with equal times, so the caller can check for
* duplicates. When pTime is not NULL, use it as a starting point for search,
* otherwise search from beginning (largest time value) of history list. */
PG_STATIC struct Hist *
mergeInsertionPoint(
struct Hist *np, /* new entry to be inserted */
struct Hist *pTime) /* hint about where to insert */
{
struct Hist *pp, *p;
if (histTail && histTail->Htime >= np->Htime)
pTime = histTail; /* new entry goes at the end */
if (histMerg && histMerg != &Histlist && histMerg != Histlist.Hnext) {
/* Check above and below previous insertion point, in case we're adding
* sequential times in the middle of the list (e.g. history -M). */
if (histMerg->Htime >= np->Htime)
pTime = histMerg;
else if (histMerg->Hprev->Htime >= np->Htime)
pTime = histMerg->Hprev;
}
if (pTime) {
/* With hint, search up the list until Htime is greater. We skip past
* the equal ones, too, so our caller can elide duplicates. */
pp = pTime;
while (pp != &Histlist && pp->Htime <= np->Htime)
pp = pp->Hprev;
} else
pp = &Histlist;
/* Search down the list while current entry's time is too large. */
while ((p = pp->Hnext) && (p->Htime > np->Htime))
pp = p; /* advance insertion point */
/* Remember recent position as hint for next time */
histMerg = pp;
return pp;
}
/* Bubble Hnum & Href in new entry down to pp through earlier part of list. */
PG_STATIC void bubbleHnumHrefDown(struct Hist *np, struct Hist *pp)
{
struct Hist *p;
for (p = Histlist.Hnext; p != pp->Hnext; p = p->Hnext) {
/* swap Hnum & Href values of p and np. */
int n = p->Hnum, r = p->Href;
p->Hnum = np->Hnum; p->Href = np->Href;
np->Hnum = n; np->Href = r;
}
}
/* Enter new command into the history list according to current settings. */
struct Hist *
enthist(
int event, /* newly incremented global eventno */
struct wordent *lp,
int docopy,
int mflg, /* true if merge requested */
int hlen) /* -1 if unknown */
{
struct Hist *p = NULL, *pp = &Histlist, *pTime = NULL;
struct Hist *np;
const Char *dp;
unsigned lpHash = 0; /* non-zero if hashing entries */
if ((dp = varval(STRhistdup)) != STRNULL) {
if (eq(dp, STRerase)) {
/* masaoki@akebono.tky.hp.com (Kobayashi Masaoki) */
createHistHashTable(hlen);
lpHash = hashhist(lp);
assert(lpHash != 0);
p = findHistHashTable(lp, lpHash);
if (p) {
if (Htime != 0 && p->Htime > Htime)
Htime = p->Htime;
/* If we are merging, and the old entry is at the place we want
* to insert the new entry, then remember the place. */
if (mflg && Htime != 0 && p->Hprev->Htime >= Htime)
pTime = p->Hprev;
if (!fastMergeErase)
renumberHist(p); /* Reset Href of subsequent entries */
hremove(p);
hfree(p);
p = NULL; /* so new entry is allocated below */
}
}
else if (eq(dp, STRall)) {
createHistHashTable(hlen);
lpHash = hashhist(lp);
assert(lpHash != 0);
p = findHistHashTable(lp, lpHash);
if (p) /* p!=NULL, only update this entry's Htime below */
eventno--; /* not adding a new event */
}
else if (eq(dp, STRprev)) {
if (pp->Hnext && heq(lp, &(pp->Hnext->Hlex))) {
p = pp->Hnext;
eventno--;
}
}
}
np = p ? p : xmalloc(sizeof(*np));
/* Pick up timestamp set by lex() in Htime if reading saved history */
if (Htime != 0) {
np->Htime = Htime;
Htime = 0;
}
else
(void) time(&(np->Htime));
if (p == np)
return np; /* reused existing entry */
/* Initialize the new entry. */
np->Hnum = np->Href = event;
if (docopy) {
copylex(&np->Hlex, lp);
if (histvalid)
np->histline = Strsave(histline.s);
else
np->histline = NULL;
}
else {
np->Hlex.next = lp->next;
lp->next->prev = &np->Hlex;
np->Hlex.prev = lp->prev;
lp->prev->next = &np->Hlex;
np->histline = NULL;
}
np->Hhash = 0;
/* The head of history list is the default insertion point.
If merging, advance insertion point, in pp, according to Htime. */
/* XXX -- In histdup=all, Htime values can be non-monotonic. */
if (mflg) { /* merge according to np->Htime */
pp = mergeInsertionPoint(np, pTime);
for (p = pp->Hnext; p && p->Htime == np->Htime; pp = p, p = p->Hnext) {
if (heq(&p->Hlex, &np->Hlex)) {
eventno--; /* duplicate, so don't add new event */
hfree(np);
return (p);
}
}
/* pp is now the last entry with time >= to np. */
if (!fastMergeErase) { /* renumber at end of loadhist */
/* Before inserting np after pp, bubble its Hnum & Href values down
* through the earlier part of list. */
bubbleHnumHrefDown(np, pp);
}
}
else
pp = &Histlist; /* insert at beginning of history */
hinsert(np, pp);
if (lpHash && hlen != 0) /* erase & all modes use hash table */
insertHistHashTable(np, lpHash);
else
discardHistHashTable();
return (np);
}
static void
hfree(struct Hist *hp)
{
assert(hp != histMerg);
if (hp->Hhash)
removeHistHashTable(hp);
freelex(&hp->Hlex);
if (hp->histline)
xfree(hp->histline);
xfree(hp);
}
PG_STATIC void
phist(struct Hist *hp, int hflg)
{
if (hp->Href < 0)
return;
if (hflg & HIST_ONLY) {
int old_output_raw;
/*
* Control characters have to be written as is (output_raw).
* This way one can preserve special characters (like tab) in
* the history file.
* From: mveksler@vnet.ibm.com (Veksler Michael)
*/
old_output_raw = output_raw;
output_raw = 1;
cleanup_push(&old_output_raw, output_raw_restore);
if (hflg & HIST_TIME)
/*
* Make file entry with history time in format:
* "+NNNNNNNNNN" (10 digits, left padded with ascii '0')
*/
xprintf("#+%010lu\n", (unsigned long)hp->Htime);
if (HistLit && hp->histline)
xprintf("%S\n", hp->histline);
else
prlex(&hp->Hlex);
cleanup_until(&old_output_raw);
}
else {
Char *cp = str2short("%h\t%T\t%R\n");
Char *p;
struct varent *vp = adrof(STRhistory);
if (vp && vp->vec != NULL && vp->vec[0] && vp->vec[1])
cp = vp->vec[1];
p = tprintf(FMT_HISTORY, cp, NULL, hp->Htime, hp);
cleanup_push(p, xfree);
for (cp = p; *cp;)
xputwchar(*cp++);
cleanup_until(p);
}
}
PG_STATIC void
dophist(int n, int hflg)
{
struct Hist *hp;
if (setintr) {
int old_pintr_disabled;
pintr_push_enable(&old_pintr_disabled);
cleanup_until(&old_pintr_disabled);
}
if ((hflg & HIST_REV) == 0) {
/* Since the history list is stored most recent first, non-reversing
* print needs to print (backwards) up the list. */
if ((unsigned)n >= histCount)
hp = histTail;
else {
for (hp = Histlist.Hnext;
--n > 0 && hp->Hnext != NULL;
hp = hp->Hnext)
;
}
if (hp == NULL)
return; /* nothing to print */
for (; hp != &Histlist; hp = hp->Hprev)
phist(hp, hflg);
} else {
for (hp = Histlist.Hnext; n-- > 0 && hp != NULL; hp = hp->Hnext)
phist(hp, hflg);
}
}
/*ARGSUSED*/
void
dohist(Char **vp, struct command *c)
{
int n, hflg = 0;
USE(c);
if (getn(varval(STRhistory)) == 0)
return;
while (*++vp && **vp == '-') {
Char *vp2 = *vp;
while (*++vp2)
switch (*vp2) {
case 'c':
hflg |= HIST_CLEAR;
break;
case 'h':
hflg |= HIST_ONLY;
break;
case 'r':
hflg |= HIST_REV;
break;
case 'S':
hflg |= HIST_SAVE;
break;
case 'L':
hflg |= HIST_LOAD;
break;
case 'M':
hflg |= HIST_MERGE;
break;
case 'T':
hflg |= HIST_TIME;
break;
default:
stderror(ERR_HISTUS, "chrSLMT");
break;
}
}
if (hflg & HIST_CLEAR) {
struct Hist *np, *hp;
for (hp = &Histlist; (np = hp->Hnext) != NULL;)
hremove(np), hfree(np);
}
if (hflg & (HIST_LOAD | HIST_MERGE))
loadhist(*vp, (hflg & HIST_MERGE) ? 1 : 0);
else if (hflg & HIST_SAVE)
rechist(*vp, 1);
else {
if (*vp)
n = getn(*vp);
else {
n = getn(varval(STRhistory));
}
dophist(n, hflg);
}
}
char *
fmthist(int fmt, ptr_t ptr)
{
struct Hist *hp = ptr;
char *buf;
switch (fmt) {
case 'h':
return xasprintf("%6d", hp->Hnum);
case 'R':
if (HistLit && hp->histline)
return xasprintf("%S", hp->histline);
else {
Char *istr, *ip;
char *p;
istr = sprlex(&hp->Hlex);
buf = xmalloc(Strlen(istr) * MB_LEN_MAX + 1);
for (p = buf, ip = istr; *ip != '\0'; ip++)
p += one_wctomb(p, *ip);
*p = '\0';
xfree(istr);
return buf;
}
default:
buf = xmalloc(1);
buf[0] = '\0';
return buf;
}
}
static void
dotlock_cleanup(void* lockpath)
{
dot_unlock((char*)lockpath);
}
/* Save history before exiting the shell. */
void
rechist(Char *fname, int ref)
{
Char *snum, *rs;
int fp, ftmp, oldidfds;
struct varent *shist;
char path[MAXPATHLEN];
struct stat st;
static Char *dumphist[] = {STRhistory, STRmhT, 0, 0};
if (fname == NULL && !ref)
return;
/*
* If $savehist is just set, we use the value of $history
* else we use the value in $savehist
*/
if (((snum = varval(STRsavehist)) == STRNULL) &&
((snum = varval(STRhistory)) == STRNULL))
snum = STRmaxint;
if (fname == NULL) {
if ((fname = varval(STRhistfile)) == STRNULL)
fname = Strspl(varval(STRhome), &STRtildothist[1]);
else
fname = Strsave(fname);
}
else
fname = globone(fname, G_ERROR);
cleanup_push(fname, xfree);
/*
* The 'savehist merge' feature is intended for an environment
* with numerous shells being in simultaneous use. Imagine
* any kind of window system. All these shells 'share' the same
* ~/.history file for recording their command line history.
* We try to handle the case of multiple shells trying to merge
* histories at the same time, by creating semi-unique filenames
* and saving the history there first and then trying to rename
* them in the proper history file.
*
* Users that like to nuke their environment require here an atomic
* loadhist-creat-dohist(dumphist)-close sequence which is given
* by optional lock parameter to savehist.
*
* jw.
*/
/*
* We need the didfds stuff before loadhist otherwise
* exec in a script will fail to print if merge is set.
* From: mveksler@iil.intel.com (Veksler Michael)
*/
oldidfds = didfds;
didfds = 0;
if ((shist = adrof(STRsavehist)) != NULL && shist->vec != NULL) {
size_t i;
int merge = 0, lock = 0;
for (i = 1; shist->vec[i]; i++) {
if (eq(shist->vec[i], STRmerge))
merge++;
if (eq(shist->vec[i], STRlock))
lock++;
}
if (merge) {
jmp_buf_t osetexit;
if (lock) {
#ifndef WINNT_NATIVE
char *lockpath = strsave(short2str(fname));
cleanup_push(lockpath, xfree);
/* Poll in 100 miliseconds interval to obtain the lock. */
if ((dot_lock(lockpath, 100) == 0))
cleanup_push(lockpath, dotlock_cleanup);
#endif
}
getexit(osetexit);
if (setexit())
loadhist(fname, 1);
resexit(osetexit);
}
}
rs = randsuf();
xsnprintf(path, sizeof(path), "%S.%S", fname, rs);
xfree(rs);
fp = xcreat(path, 0600);
if (fp == -1) {
didfds = oldidfds;
cleanup_until(fname);
return;
}
/* Try to preserve ownership and permissions of the original history file */
#ifndef WINNT_NATIVE
if (stat(short2str(fname), &st) != -1) {
TCSH_IGNORE(fchown(fp, st.st_uid, st.st_gid));
TCSH_IGNORE(fchmod(fp, st.st_mode));
}
#else
UNREFERENCED_PARAMETER(st);
#endif
ftmp = SHOUT;
SHOUT = fp;
dumphist[2] = snum;
dohist(dumphist, NULL);
xclose(fp);
SHOUT = ftmp;
didfds = oldidfds;
#ifndef WINNT_NATIVE
(void)rename(path, short2str(fname));
#else
(void)ReplaceFile( short2str(fname),path,NULL,0,NULL,NULL);
#endif
cleanup_until(fname);
}
/* This is the entry point for loading history data from a file. */
void
loadhist(Char *fname, int mflg)
{
static Char *loadhist_cmd[] = {STRsource, NULL, NULL, NULL};
loadhist_cmd[1] = mflg ? STRmm : STRmh;
if (fname != NULL)
loadhist_cmd[2] = fname;
else if ((fname = varval(STRhistfile)) != STRNULL)
loadhist_cmd[2] = fname;
else
loadhist_cmd[2] = STRtildothist;
dosource(loadhist_cmd, NULL);
/* During history merging (enthist sees mflg set), we disable management of
* Hnum and Href (because fastMergeErase is true). So now reset all the
* values based on the final ordering of the history list. */
if (mflg) {
int n = eventno;
struct Hist *hp = &Histlist;
while ((hp = hp->Hnext))
hp->Hnum = hp->Href = n--;
}
}
void
sethistory(int n)
{
histlen = n;
discardExcess(histlen);
}
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