to speed up mksh, get rid of arc4random(3) uses and use the LCG always;
depend on ASLR for seeding
This commit is contained in:
tg
108
var.c
108
var.c
@ -22,7 +22,7 @@
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#include "sh.h"
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__RCSID("$MirOS: src/bin/mksh/var.c,v 1.104 2010/01/28 20:26:52 tg Exp $");
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__RCSID("$MirOS: src/bin/mksh/var.c,v 1.105 2010/07/04 17:33:58 tg Exp $");
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/*
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* Variables
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@ -46,12 +46,9 @@ static int getint(struct tbl *, mksh_ari_t *, bool);
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static mksh_ari_t intval(struct tbl *);
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static struct tbl *arraysearch(struct tbl *, uint32_t);
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static const char *array_index_calc(const char *, bool *, uint32_t *);
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#if !HAVE_ARC4RANDOM
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static uint32_t oaathash_update(register uint32_t, register const uint8_t *,
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register size_t);
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static uint32_t lcg_state = 5381;
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#endif
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static uint32_t oaathash_finalise(register uint32_t);
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uint8_t set_refflag = 0;
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@ -982,7 +979,7 @@ makenv(void)
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return ((char **)XPclose(denv));
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}
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#if !HAVE_ARC4RANDOM
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/* Bob Jenkins' one-at-a-time hash */
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static uint32_t
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oaathash_update(register uint32_t h, register const uint8_t *cp,
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register size_t n)
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@ -996,33 +993,43 @@ oaathash_update(register uint32_t h, register const uint8_t *cp,
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return (h);
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}
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void
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change_random(const void *vp, size_t n)
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static uint32_t
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oaathash_finalise(register uint32_t h)
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{
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register uint32_t h = 0x100;
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struct {
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const void *sp, *bp, *dp;
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size_t dsz;
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struct timeval tv;
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uint32_t s;
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} i;
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i.dp = vp;
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i.dsz = n;
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i.s = lcg_state;
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i.bp = &lcg_state;
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i.sp = &i;
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gettimeofday(&i.tv, NULL);
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h = oaathash_update(oaathash_update(h, (void *)&i, sizeof(i)), vp, n);
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/* oaathash_finalise */
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h += h << 3;
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h ^= h >> 11;
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h += h << 15;
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lcg_state = h;
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return (h);
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}
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uint32_t
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oaathash_full(register const uint8_t *bp)
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{
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register uint32_t h = 0;
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register uint8_t c;
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while ((c = *bp++)) {
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h += c;
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h += h << 10;
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h ^= h >> 6;
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}
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return (oaathash_finalise(h));
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}
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void
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change_random(const void *vp, size_t n)
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{
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register uint32_t h = 0x100;
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kshstate_v.cr_dp = vp;
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kshstate_v.cr_dsz = n;
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gettimeofday(&kshstate_v.cr_tv, NULL);
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h = oaathash_update(oaathash_update(h, (void *)&kshstate_v,
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sizeof(kshstate_v)), vp, n);
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kshstate_v.lcg_state_ = oaathash_finalise(h);
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}
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#endif
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/*
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* handle special variables with side effects - PATH, SECONDS.
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@ -1074,15 +1081,12 @@ getspec(struct tbl *vp)
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return;
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break;
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case V_RANDOM:
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#if HAVE_ARC4RANDOM
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i = arc4random() & 0x7FFF;
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#else
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/*
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* this is the same Linear Congruential PRNG as Borland
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* C/C++ allegedly uses in its built-in rand() function
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*/
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i = ((lcg_state = 22695477 * lcg_state + 1) >> 16) & 0x7FFF;
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#endif
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i = ((kshstate_v.lcg_state_ =
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22695477 * kshstate_v.lcg_state_ + 1) >> 16) & 0x7FFF;
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break;
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case V_HISTSIZE:
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i = histsize;
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@ -1196,25 +1200,11 @@ setspec(struct tbl *vp)
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x_lins = i;
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break;
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case V_RANDOM:
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#if HAVE_ARC4RANDOM
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#if HAVE_ARC4RANDOM_PUSHB
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if (Flag(FARC4RANDOM))
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/*
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* things like initialisation, environment import,
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* etc. are already done
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*/
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arc4random_pushb(&i, sizeof(i));
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else
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/* during start-up phase or somesuch */
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#endif /* HAVE_ARC4RANDOM_PUSHB */
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arc4random_addrandom((void *)&i, sizeof(i));
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#else /* !HAVE_ARC4RANDOM */
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/*
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* mksh R40+ no longer has the traditional repeatability
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* mksh R39d+ no longer has the traditional repeatability
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* of $RANDOM sequences, but always retains state
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*/
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change_random(&i, sizeof(i));
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#endif /* !HAVE_ARC4RANDOM */
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break;
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case V_SECONDS:
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{
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@ -1259,13 +1249,12 @@ unsetspec(struct tbl *vp)
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unspecial(vp->name);
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break;
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/* AT&T ksh man page says OPTIND, OPTARG and _ lose special meaning,
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* but OPTARG does not (still set by getopts) and _ is also still
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* set in various places.
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* Don't know what AT&T does for:
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* HISTSIZE, HISTFILE,
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* Unsetting these in AT&T ksh does not loose the 'specialness':
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* no effect: IFS, COLUMNS, PATH, TMPDIR
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/*
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* AT&T ksh man page says OPTIND, OPTARG and _ lose special
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* meaning, but OPTARG does not (still set by getopts) and _ is
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* also still set in various places. Don't know what AT&T does
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* for HISTSIZE, HISTFILE. Unsetting these in AT&T ksh does not
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* loose the 'specialness': IFS, COLUMNS, PATH, TMPDIR
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*/
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}
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}
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@ -1452,3 +1441,14 @@ change_winsz(void)
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if (x_lins < MIN_LINS)
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x_lins = 24;
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}
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uint32_t
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evilhash(const char *s)
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{
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register uint32_t h = 0x100;
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h = oaathash_update(h, (void *)&kshstate_f, sizeof(kshstate_f));
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kshstate_f.h = oaathash_full((const uint8_t *)s);
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return (oaathash_finalise(oaathash_update(h,
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(void *)&kshstate_f.h, sizeof(kshstate_f.h))));
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}
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