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• overhaul handling of special variables

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• use a combination of the one-at-a-time hash and an LCG for handling
  the $RANDOM special if !HAVE_ARC4RANDOM instead of rand(3)/srand(3)
  and get rid of time(3) usage to reduce import footprint
• raise entropy state (mostly in the !HAVE_ARC4RANDOM case though…)
• simplify handling of the $RANDOM_SPECIAL generally
• tweak hash() to save a temp var for non-optimising compilers
• some int → mksh_ari_t and other type fixes
• general tweaking of code and comments
This commit is contained in:
tg
2009-10-17 21:16:05 +00:00
parent 9f4376d2ad
commit eafe88aa74
6 changed files with 200 additions and 172 deletions
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251
var.c
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@ -22,7 +22,7 @@
#include "sh.h"
__RCSID("$MirOS: src/bin/mksh/var.c,v 1.94 2009/09/27 10:31:06 tg Exp $");
__RCSID("$MirOS: src/bin/mksh/var.c,v 1.95 2009/10/17 21:16:05 tg Exp $");
/*
* Variables
@ -46,11 +46,11 @@ static int getint(struct tbl *, mksh_ari_t *, bool);
static mksh_ari_t intval(struct tbl *);
static struct tbl *arraysearch(struct tbl *, uint32_t);
static const char *array_index_calc(const char *, bool *, uint32_t *);
static int rnd_get(void);
#if HAVE_ARC4RANDOM
static void rnd_set(unsigned long);
#else
#define rnd_set change_random
#if !HAVE_ARC4RANDOM
static uint32_t oaathash_update(register uint32_t, register const uint8_t *,
register size_t);
static uint32_t lcg_seed = 5381;
#endif
uint8_t set_refflag = 0;
@ -972,58 +972,45 @@ makenv(void)
return ((char **)XPclose(denv));
}
#if HAVE_ARC4RANDOM
static int
rnd_get(void)
#if !HAVE_ARC4RANDOM
static uint32_t
oaathash_update(register uint32_t h, register const uint8_t *cp,
register size_t n)
{
return (arc4random() & 0x7FFF);
}
static void
rnd_set(unsigned long newval)
{
#if HAVE_ARC4RANDOM_PUSHB
if (Flag(FARC4RANDOM))
/* initialisation, environment import, etc. already done */
arc4random_pushb(&newval, sizeof(newval));
else
/* during start-up phase or somesuch */
#endif
arc4random_addrandom((void *)&newval, sizeof(newval));
}
#else
static int
rnd_get(void)
{
return (rand() & 0x7FFF);
}
/*
* Called after a fork to bump the random number generator.
* Done to ensure children will not get the same random number sequence
* as the parent processes.
* Also called as rnd_set - mksh R40+ no longer has the traditional
* repeatability of randomness sequences, state is always retained.
*/
void
change_random(unsigned long newval)
{
register unsigned int h;
h = rand();
while (newval) {
h += (newval & 0xFF);
while (n--) {
h += *cp++;
h += h << 10;
h ^= h >> 6;
newval >>= 8;
}
return (h);
}
void
change_random(const void *vp, size_t n)
{
register uint32_t h;
struct {
const void *sp, *bp, *dp;
size_t dsz;
struct timeval tv;
uint32_t s;
} i;
i.dp = vp;
i.dsz = n;
i.s = lcg_seed;
i.bp = &lcg_seed;
i.sp = &i;
gettimeofday(&i.tv, NULL);
h = oaathash_update(oaathash_update(1, (void *)&i, sizeof(i)), vp, n);
/* oaathash_finalise */
h += h << 3;
h ^= h >> 11;
h += h << 15;
/* pass all of it, in case RAND_MAX is large */
srand(h);
lcg_seed = h;
}
#endif
@ -1058,82 +1045,84 @@ static int user_lineno; /* what user set $LINENO to */
static void
getspec(struct tbl *vp)
{
int i;
register mksh_ari_t i;
int st;
switch ((i = special(vp->name))) {
switch ((st = special(vp->name))) {
case V_SECONDS:
vp->flag &= ~SPECIAL;
/* On start up the value of SECONDS is used before seconds
* has been set - don't do anything in this case
/*
* On start up the value of SECONDS is used before
* it has been set - don't do anything in this case
* (see initcoms[] in main.c).
*/
if (vp->flag & ISSET) {
struct timeval tv;
gettimeofday(&tv, NULL);
setint(vp, tv.tv_sec - seconds);
}
vp->flag |= SPECIAL;
i = tv.tv_sec - seconds;
} else
return;
break;
case V_RANDOM:
vp->flag &= ~SPECIAL;
setint(vp, rnd_get());
vp->flag |= SPECIAL;
#if HAVE_ARC4RANDOM
i = arc4random() & 0x7FFF;
#else
/*
* this is the same Linear Congruential PRNG as Borland
* C/C++ allegedly uses in its built-in rand() function
*/
i = ((lcg_seed = 22695477 * lcg_seed + 1) >> 16) & 0x7FFF;
#endif
break;
case V_HISTSIZE:
vp->flag &= ~SPECIAL;
setint(vp, (mksh_ari_t)histsize);
vp->flag |= SPECIAL;
i = histsize;
break;
case V_OPTIND:
vp->flag &= ~SPECIAL;
setint(vp, (mksh_ari_t)user_opt.uoptind);
vp->flag |= SPECIAL;
i = user_opt.uoptind;
break;
case V_LINENO:
vp->flag &= ~SPECIAL;
setint(vp, (mksh_ari_t)current_lineno + user_lineno);
vp->flag |= SPECIAL;
i = current_lineno + user_lineno;
break;
case V_COLUMNS:
case V_LINES:
/* Do NOT export COLUMNS/LINES. Many applications
/*
* Do NOT export COLUMNS/LINES. Many applications
* check COLUMNS/LINES before checking ws.ws_col/row,
* so if the app is started with C/L in the environ
* and the window is then resized, the app won't
* see the change cause the environ doesn't change.
*/
vp->flag &= ~SPECIAL;
change_winsz();
setint(vp, i == V_COLUMNS ? x_cols : x_lins);
vp->flag |= SPECIAL;
i = st == V_COLUMNS ? x_cols : x_lins;
break;
default:
/* do nothing, do not touch vp at all */
return;
}
vp->flag &= ~SPECIAL;
setint(vp, i);
vp->flag |= SPECIAL;
}
static void
setspec(struct tbl *vp)
{
int i;
mksh_ari_t i;
char *s;
int st;
switch (special(vp->name)) {
switch ((st = special(vp->name))) {
case V_PATH:
if (path)
afree(path, APERM);
s = str_val(vp);
strdupx(path, s, APERM);
flushcom(1); /* clear tracked aliases */
break;
return;
case V_IFS:
setctypes(s = str_val(vp), C_IFS);
ifs0 = *s;
break;
case V_OPTIND:
vp->flag &= ~SPECIAL;
getopts_reset((int)intval(vp));
vp->flag |= SPECIAL;
break;
return;
case V_TMPDIR:
if (tmpdir) {
afree(tmpdir, APERM);
@ -1151,54 +1140,84 @@ setspec(struct tbl *vp)
strdupx(tmpdir, s, APERM);
}
break;
case V_HISTSIZE:
vp->flag &= ~SPECIAL;
sethistsize((int)intval(vp));
vp->flag |= SPECIAL;
break;
#if HAVE_PERSISTENT_HISTORY
case V_HISTFILE:
sethistfile(str_val(vp));
break;
#endif
case V_COLUMNS:
vp->flag &= ~SPECIAL;
if ((i = intval(vp)) >= MIN_COLS)
x_cols = i;
vp->flag |= SPECIAL;
break;
case V_LINES:
vp->flag &= ~SPECIAL;
if ((i = intval(vp)) >= MIN_LINS)
x_lins = i;
vp->flag |= SPECIAL;
break;
case V_RANDOM:
vp->flag &= ~SPECIAL;
rnd_set(intval(vp));
vp->flag |= SPECIAL;
break;
case V_SECONDS:
vp->flag &= ~SPECIAL;
{
struct timeval tv;
gettimeofday(&tv, NULL);
seconds = tv.tv_sec - intval(vp);
}
vp->flag |= SPECIAL;
break;
case V_TMOUT:
/* AT&T ksh seems to do this (only listen if integer) */
if (vp->flag & INTEGER)
ksh_tmout = vp->val.i >= 0 ? vp->val.i : 0;
break;
/* common sub-cases */
case V_OPTIND:
case V_HISTSIZE:
case V_COLUMNS:
case V_LINES:
case V_RANDOM:
case V_SECONDS:
case V_LINENO:
vp->flag &= ~SPECIAL;
/* The -1 is because line numbering starts at 1. */
user_lineno = (unsigned int)intval(vp) - current_lineno - 1;
i = intval(vp);
vp->flag |= SPECIAL;
break;
default:
/* do nothing, do not touch vp at all */
return;
}
/* process the singular parts of the common cases */
switch (st) {
case V_OPTIND:
getopts_reset((int)i);
break;
case V_HISTSIZE:
sethistsize((int)i);
break;
case V_COLUMNS:
if (i >= MIN_COLS)
x_cols = i;
break;
case V_LINES:
if (i >= MIN_LINS)
x_lins = i;
break;
case V_RANDOM:
#if HAVE_ARC4RANDOM
#if HAVE_ARC4RANDOM_PUSHB
if (Flag(FARC4RANDOM))
/*
* things like initialisation, environment import,
* etc. are already done
*/
arc4random_pushb(&i, sizeof(i));
else
/* during start-up phase or somesuch */
#endif /* HAVE_ARC4RANDOM_PUSHB */
arc4random_addrandom((void *)&i, sizeof(i));
#else /* !HAVE_ARC4RANDOM */
/*
* mksh R40+ no longer has the traditional repeatability
* of $RANDOM sequences, but always retains state
*/
change_random(&i, sizeof(i));
#endif /* !HAVE_ARC4RANDOM */
break;
case V_SECONDS:
{
struct timeval tv;
gettimeofday(&tv, NULL);
seconds = tv.tv_sec - i;
}
break;
case V_LINENO:
/* The -1 is because line numbering starts at 1. */
user_lineno = (unsigned int)i - current_lineno - 1;
break;
}
}