From ce13b7600277478055de0b7c38b483a76145efd2 Mon Sep 17 00:00:00 2001
From: Denis Vlasenko <vda.linux@googlemail.com>
Date: Sun, 29 Jun 2008 02:25:53 +0000
Subject: libbb: shrink monotonic_XXX functions, introduce monotonic_ns (unused
for now)
function old new delta
get_mono - 31 +31
sv_main 1228 1234 +6
expand 1693 1697 +4
get_address 178 181 +3
utoa_to_buf 108 110 +2
builtin_exit 46 48 +2
qrealloc 36 33 -3
qgravechar 109 106 -3
ash_main 1383 1380 -3
grep_file 850 846 -4
popstring 140 134 -6
monotonic_us 85 60 -25
monotonic_sec 41 16 -25
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 5/7 up/down: 48/-69) Total: -21 bytes
---
shell/ash.c | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)
(limited to 'shell')
diff --git a/shell/ash.c b/shell/ash.c
index 9c3216243..85064d5af 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -9615,7 +9615,6 @@ setcmd(int argc ATTRIBUTE_UNUSED, char **argv ATTRIBUTE_UNUSED)
}
#if ENABLE_ASH_RANDOM_SUPPORT
-/* Roughly copied from bash.. */
static void
change_random(const char *value)
{
@@ -9636,10 +9635,11 @@ change_random(const char *value)
if (random_galois_LFSR < 0) /* if we just shifted 1 out of msb... */
t ^= MASK;
random_galois_LFSR = t;
- /* Both are weak, xoring them gives better randomness
+ /* Both are weak, combining them gives better randomness
* and ~2^64 period. & 0x7fff is probably bash compat
- * for $RANDOM range. */
- t = (t ^ random_LCG) & 0x7fff;
+ * for $RANDOM range. Combining with subtraction is
+ * just for fun. + and ^ would work equally well. */
+ t = (t - random_LCG) & 0x7fff;
/* set without recursion */
setvar(vrandom.text, utoa(t), VNOFUNC);
vrandom.flags &= ~VNOFUNC;
@@ -13432,7 +13432,9 @@ int ash_main(int argc ATTRIBUTE_UNUSED, char **argv)
rootpid = getpid();
#if ENABLE_ASH_RANDOM_SUPPORT
- random_galois_LFSR = random_LCG = rootpid + time(NULL);
+ /* Can use monotonic_ns() for better randomness but for now it is
+ * not used anywhere else in busybox... so avoid bloat */
+ random_galois_LFSR = random_LCG = rootpid + monotonic_us();
#endif
init();
setstackmark(&smark);
--
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