Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

1) POSIX requires rand(3) return values to be in the [0, RAND_MAX]
range, but ACM formula we use have internal state (and return value) in
the [1, 0x7ffffffe] range, so our RAND_MAX (0x7fffffff) is never reached
because it is off by one, zero is not reached too.

Correct both RAND_MAX and rand(3) return value, shifting last one
to the 0 by 1 subtracted, resulting POSIXed [0, 0x7ffffffd(=new
RAND_MAX)] range.

2) Add a checks for not overflowing on too big seeds. It may happens on
the machines, where sizeof(unsigned int) > 32 bits.

This change is binary compatible because range is reduced, not expanded,
so no bump is needed.

Reviewed by: bde
Approved by: re (glebius)

MFC r249035:

Replace access to /dev/random with the kernel pseudo-random number
source sysctl(KERN_ARND) and remove the fallback code.

Obtained from: OpenBSD

MFC r241373:
Remove undefined behavior from sranddev() and
srandomdev(). This doesn't actually work
with any modern C compiler:

In particular, both clang and modern gcc
verisons silently elide any xor operation
with 'junk'.

Approved by: cperciva (implicit)

Copy head to stable/9 as part of 9.0-RELEASE release cycle.

Approved by: re (implicit)

Fix typo in the comment

Per Regents of the University of Calfornia letter, remove advertising
clause.

# If I've done so improperly on a file, please let me know.

Back out "drop first N values" method of removing monotonically increased
seed->first value correlation. It breaks rand_r()... Other possible methods
like shuffling inside aray will breaks rand_r() too, because it assumes
only one word state, i.e. nothing extra can be added after seed assignment
in srand().

BTW, for old formulae seed->first value correlation is not so monotonically
increased as with other Linear Congruential Generators of this type only
becase arithmetic overflow happens. But overflow affects distribution
and lower bits very badly, as many articles says, such type of overflow
not improves PRNG.

So, monotonically increased seed->first value correlation problem remains...

Since we drop NSHUFF values now, set default seed to what it becomes
after srand(1)

For rand(3) and random(3) TYPE_0 drop NSHUFF values right after srand{om}()
to remove part of seed -> 1st value correlation. Correlation still remains
because of algorithm limits. Note that old algorithm have even stronger
correlation, especially in the lower bits area, but not eye-visible, as
current one.

Park & Miller PRNG can be safely initialized with any value but 0 and stuck
at 0 as designed. Its BSD adaptation tries to fight it by mapping 0 to
2147483647 after calculation, but this method not works since 2147483647
seed returns to 0 again on the next interation. Instead of after calculation
mapping, map 0 to another value _before_ calculation, so it never stucks.

For some combinations of variable sizes and RAND_MAX value rand_r()
may store less amount bits for seed, than available. Fix it.

Add missing #include "namespace.h".

Fix the style of the SCM ID's.
I believe have made all of libc .c's as consistent as possible.

Add a long-overdue nail to the deprecated /dev/urandom interface
by asking some things that need unpredictable numbers to read
/dev/random instead.

urandom(4) -> random(4) in comments.

PR: 27858
Submitted by: Yoshihiro Koya <Yoshihiro.Koya@math.yokohama-cu.ac.jp>
Reviewed by: md5(1)
Approved by: markm

Add #include "un-namespace.h"

srand*dev() fallback code: change ^getpid() to ^(getpid() << 16) to allow
change of high word part too to produce more interesting seed distribution.

Add sranddev() since srand() is not vary much with seed, typical time

Use formula with better random distribution for rand()

Even better formula from random() could not be intetgrated because rand_r()
supposed to store its state in the single variable (but table needed for
random() algorithm integration).

Added Posix rand_r function.

This commit was generated by cvs2svn to compensate for changes in r1573,
which included commits to RCS files with non-trunk default branches.

BSD 4.4 Lite Lib Sources