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	/* random.c - random number generator
	* Copyright (C) 1998, 2000, 2001, 2002 Free Software Foundation, Inc.
	*
	* This file is part of Libgcrypt.
	*
	* Libgcrypt is free software; you can redistribute it and/or modify
	* it under the terms of the GNU Lesser General Public License as
	* published by the Free Software Foundation; either version 2.1 of
	* the License, or (at your option) any later version.
	*
	* Libgcrypt is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	* GNU Lesser General Public License for more details.
	*
	* You should have received a copy of the GNU Lesser General Public
	* License along with this program; if not, write to the Free Software
	* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
	*/

	/****************
	* This random number generator is modelled after the one described
	* in Peter Gutmann's Paper: "Software Generation of Practically
	* Strong Random Numbers".
	*/


	#include <config.h>
	#include <stdio.h>
	#include <stdlib.h>
	#include <assert.h>
	#include <errno.h>
	#include <string.h>
	#include <sys/time.h>
	#include <sys/types.h>
	#include <sys/stat.h>
	#include <unistd.h>
	#include <fcntl.h>
	#include <time.h>
	#ifdef HAVE_GETHRTIME
	#include <sys/times.h>
	#endif
	#ifdef HAVE_GETTIMEOFDAY
	#include <sys/times.h>
	#endif
	#ifdef HAVE_GETRUSAGE
	#include <sys/resource.h>
	#endif
	#ifdef __MINGW32__
	#include <process.h>
	#endif
	#include "g10lib.h"
	#include "rmd.h"
	#include "random.h"
	#include "rand-internal.h"
	#include "dynload.h"
	#include "cipher.h" /* only used for the rmd160_hash_buffer() prototype */
	#include "ath.h"

	#ifndef RAND_MAX /* for SunOS */
	#define RAND_MAX 32767
	#endif


	#if SIZEOF_UNSIGNED_LONG == 8
	#define ADD_VALUE 0xa5a5a5a5a5a5a5a5
	#elif SIZEOF_UNSIGNED_LONG == 4
	#define ADD_VALUE 0xa5a5a5a5
	#else
	#error weird size for an unsigned long
	#endif

	#define BLOCKLEN 64 /* hash this amount of bytes */
	#define DIGESTLEN 20 /* into a digest of this length (rmd160) */
	/* poolblocks is the number of digests which make up the pool
	* and poolsize must be a multiple of the digest length
	* to make the AND operations faster, the size should also be
	* a multiple of ulong
	*/
	#define POOLBLOCKS 30
	#define POOLSIZE (POOLBLOCKS*DIGESTLEN)
	#if (POOLSIZE % SIZEOF_UNSIGNED_LONG)
	#error Please make sure that poolsize is a multiple of ulong
	#endif
	#define POOLWORDS (POOLSIZE / SIZEOF_UNSIGNED_LONG)


	static int is_initialized;
	#define MASK_LEVEL(a) do {if( a > 2 ) a = 2; else if( a < 0 ) a = 0; } while(0)
	static char rndpool; / allocated size is POOLSIZE+BLOCKLEN */
	static char keypool; / allocated size is POOLSIZE+BLOCKLEN */
	static size_t pool_readpos;
	static size_t pool_writepos;
	static int pool_filled;
	static int pool_balance;
	static int just_mixed;
	static int did_initial_extra_seeding;
	static char *seed_file_name;
	static int allow_seed_file_update;

	static unsigned char failsafe_digest[DIGESTLEN];
	static int failsafe_digest_valid;

	static int secure_alloc;
	static int quick_test;
	static int faked_rng;

	static ath_mutex_t pool_lock = ATH_MUTEX_INITIALIZER;
	static int pool_is_locked; /* only used for assertion */

	static byte *get_random_bytes( size_t nbytes, int level, int secure );
	static void read_pool( byte *buffer, size_t length, int level );
	static void add_randomness( const void *buffer, size_t length, int source );
	static void random_poll(void);
	static void do_fast_random_poll (void);
	static void read_random_source( int requester, size_t length, int level);
	static int gather_faked( void (add)(const void, size_t, int), int requester,
	size_t length, int level );

	static struct {
	ulong mixrnd;
	ulong mixkey;
	ulong slowpolls;
	ulong fastpolls;
	ulong getbytes1;
	ulong ngetbytes1;
	ulong getbytes2;
	ulong ngetbytes2;
	ulong addbytes;
	ulong naddbytes;
	} rndstats;


	/* Note, we assume that this function is used before any concurrent
	access happens */
	static void
	initialize(void)
	{
	int err;

	err = ath_mutex_init (&pool_lock);
	if (err)
	log_fatal ("failed to create the pool lock: %s\n", strerror (err) );

	/* The data buffer is allocated somewhat larger, so that we can use
	this extra space (which is allocated in secure memory) as a
	temporary hash buffer */
	rndpool = secure_alloc ? gcry_xcalloc_secure(1,POOLSIZE+BLOCKLEN)
	: gcry_xcalloc(1,POOLSIZE+BLOCKLEN);
	keypool = secure_alloc ? gcry_xcalloc_secure(1,POOLSIZE+BLOCKLEN)
	: gcry_xcalloc(1,POOLSIZE+BLOCKLEN);
	is_initialized = 1;
	_gcry_cipher_modules_constructor ();
	}

	static void
	burn_stack (int bytes)
	{
	char buf[128];

	memset (buf, 0, sizeof buf);
	bytes -= sizeof buf;
	if (bytes > 0)
	burn_stack (bytes);
	}


	void
	_gcry_random_dump_stats()
	{
	log_info (
	"random usage: poolsize=%d mixed=%lu polls=%lu/%lu added=%lu/%lu\n"
	" outmix=%lu getlvl1=%lu/%lu getlvl2=%lu/%lu\n",
	POOLSIZE, rndstats.mixrnd, rndstats.slowpolls, rndstats.fastpolls,
	rndstats.naddbytes, rndstats.addbytes,
	rndstats.mixkey, rndstats.ngetbytes1, rndstats.getbytes1,
	rndstats.ngetbytes2, rndstats.getbytes2 );
	}

	void
	_gcry_secure_random_alloc()
	{
	secure_alloc = 1;
	}


	int
	_gcry_quick_random_gen( int onoff )
	{
	int last;

	/* No need to lock it here because we are only initializing. A
	prerequisite of the entire code is that it has already been
	initialized before any possible concurrent access */
	read_random_source(0,0,0); /* init */
	last = quick_test;
	if( onoff != -1 )
	quick_test = onoff;
	return faked_rng? 1 : last;
	}

	int
	_gcry_random_is_faked()
	{
	if( !is_initialized )
	initialize();
	return faked_rng \|\| quick_test;
	}

	/****************
	* Return a pointer to a randomized buffer of level 0 and LENGTH bits
	* caller must free the buffer.
	* Note: The returned value is rounded up to bytes.
	*/
	static byte *
	get_random_bytes( size_t nbytes, int level, int secure )
	{
	byte buf, p;
	int err;

	if( quick_test && level > 1 )
	level = 1;
	MASK_LEVEL(level);

	err = ath_mutex_lock (&pool_lock);
	if (err)
	log_fatal ("failed to acquire the pool lock: %s\n", strerror (err));
	pool_is_locked = 1;
	if( level == 1 ) {
	rndstats.getbytes1 += nbytes;
	rndstats.ngetbytes1++;
	}
	else if( level >= 2 ) {
	rndstats.getbytes2 += nbytes;
	rndstats.ngetbytes2++;
	}

	buf = secure && secure_alloc ? gcry_xmalloc_secure( nbytes )
	: gcry_xmalloc( nbytes );
	for( p = buf; nbytes > 0; ) {
	size_t n = nbytes > POOLSIZE? POOLSIZE : nbytes;
	read_pool( p, n, level );
	nbytes -= n;
	p += n;
	}

	pool_is_locked = 0;
	err = ath_mutex_unlock (&pool_lock);
	if (err)
	log_fatal ("failed to release the pool lock: %s\n", strerror (err));
	return buf;
	}

	void *
	gcry_random_bytes( size_t nbytes, enum gcry_random_level level )
	{
	if (!is_initialized)
	initialize();
	return get_random_bytes( nbytes, level, 0 );
	}

	void *
	gcry_random_bytes_secure( size_t nbytes, enum gcry_random_level level )
	{
	if (!is_initialized)
	initialize();
	return get_random_bytes( nbytes, level, 1 );
	}


	/* Fill the buffer with LENGTH bytes of cryptographically strong
	random bytes. level 0 is not very strong, 1 is strong enough for
	most usage, 2 is good for key generation stuff but may be very
	slow. */
	void
	gcry_randomize (byte *buffer, size_t length, enum gcry_random_level level)
	{
	byte *p;
	int err;

	if (!is_initialized)
	initialize ();

	if( quick_test && level > 1 )
	level = 1;
	MASK_LEVEL(level);

	err = ath_mutex_lock (&pool_lock);
	if (err)
	log_fatal ("failed to acquire the pool lock: %s\n", strerror (err));
	pool_is_locked = 1;
	if (level == 1)
	{
	rndstats.getbytes1 += length;
	rndstats.ngetbytes1++;
	}
	else if (level >= 2)
	{
	rndstats.getbytes2 += length;
	rndstats.ngetbytes2++;
	}

	for (p = buffer; length > 0;)
	{
	size_t n = length > POOLSIZE? POOLSIZE : length;
	read_pool (p, n, level);
	length -= n;
	p += n;
	}

	pool_is_locked = 0;
	err = ath_mutex_unlock (&pool_lock);
	if (err)
	log_fatal ("failed to release the pool lock: %s\n", strerror (err));
	}




	/*
	Mix the pool:

	\|........blocks*20byte........\|20byte\|..44byte..\|
	<..44byte..> <20byte>
	\| \|
	\| +------+
	+---------------------------\|----------+
	v v
	\|........blocks*20byte........\|20byte\|..44byte..\|
	<.....64bytes.....>
	\|
	+----------------------------------+
	Hash
	v
	\|.............................\|20byte\|..44byte..\|
	<20byte><20byte><..44byte..>
	\| \|
	\| +---------------------+
	+-----------------------------+ \|
	v v
	\|.............................\|20byte\|..44byte..\|
	<.....64byte......>
	\|
	+-------------------------+
	Hash
	v
	\|.............................\|20byte\|..44byte..\|
	<20byte><20byte><..44byte..>

	and so on until we did this for all blocks.

	*/
	static void
	mix_pool(byte *pool)
	{
	char *hashbuf = pool + POOLSIZE;
	char p, pend;
	int i, n;
	RMD160_CONTEXT md;

	assert (pool_is_locked);
	_gcry_rmd160_init( &md );
	#if DIGESTLEN != 20
	# error must have a digest length of 20 for ripe-md-160
	#endif
	/* loop over the pool */
	pend = pool + POOLSIZE;
	memcpy(hashbuf, pend - DIGESTLEN, DIGESTLEN );
	memcpy(hashbuf+DIGESTLEN, pool, BLOCKLEN-DIGESTLEN);
	_gcry_rmd160_mixblock( &md, hashbuf);
	memcpy(pool, hashbuf, 20 );
	if (failsafe_digest_valid && (char *)pool == rndpool)
	{
	for (i=0; i < 20; i++)
	pool[i] ^= failsafe_digest[i];
	}

	p = pool;
	for( n=1; n < POOLBLOCKS; n++ ) {
	memcpy(hashbuf, p, DIGESTLEN );

	p += DIGESTLEN;
	if( p+DIGESTLEN+BLOCKLEN < pend )
	memcpy(hashbuf+DIGESTLEN, p+DIGESTLEN, BLOCKLEN-DIGESTLEN);
	else {
	char *pp = p+DIGESTLEN;
	for(i=DIGESTLEN; i < BLOCKLEN; i++ ) {
	if( pp >= pend )
	pp = pool;
	hashbuf[i] = *pp++;
	}
	}

	_gcry_rmd160_mixblock( &md, hashbuf);
	memcpy(p, hashbuf, 20 );
	}
	/* Hmmm: our hash implementation does only leave small parts (64
	bytes) of the pool on the stack, so I thnik it ios okay not to
	require secure memory here. Before we use this pool, it gets
	copied to the help buffer anyway. */
	if ( (char*)pool == rndpool)
	{
	_gcry_rmd160_hash_buffer (failsafe_digest, pool, POOLSIZE);
	failsafe_digest_valid = 1;
	}
	burn_stack (384); /* for the rmd160_mixblock(), rmd160_hash_buffer */
	}

	void
	_gcry_set_random_seed_file( const char *name )
	{
	if( seed_file_name )
	BUG();
	seed_file_name = gcry_xstrdup( name );
	}

	/****************
	* Read in a seed form the random_seed file
	* and return true if this was successful
	*/
	static int
	read_seed_file()
	{
	int fd;
	struct stat sb;
	unsigned char buffer[POOLSIZE];
	int n;

	assert (pool_is_locked);
	if( !seed_file_name )
	return 0;

	#ifdef HAVE_DOSISH_SYSTEM
	fd = open( seed_file_name, O_RDONLY \| O_BINARY );
	#else
	fd = open( seed_file_name, O_RDONLY );
	#endif
	if( fd == -1 && errno == ENOENT) {
	allow_seed_file_update = 1;
	return 0;
	}

	if( fd == -1 ) {
	log_info(_("can't open `%s': %s\n"), seed_file_name, strerror(errno) );
	return 0;
	}
	if( fstat( fd, &sb ) ) {
	log_info(_("can't stat `%s': %s\n"), seed_file_name, strerror(errno) );
	close(fd);
	return 0;
	}
	if( !S_ISREG(sb.st_mode) ) {
	log_info(_("`%s' is not a regular file - ignored\n"), seed_file_name );
	close(fd);
	return 0;
	}
	if( !sb.st_size ) {
	log_info(_("note: random_seed file is empty\n") );
	close(fd);
	allow_seed_file_update = 1;
	return 0;
	}
	if( sb.st_size != POOLSIZE ) {
	log_info(_("warning: invalid size of random_seed file - not used\n") );
	close(fd);
	return 0;
	}
	do {
	n = read( fd, buffer, POOLSIZE );
	} while( n == -1 && errno == EINTR );
	if( n != POOLSIZE ) {
	log_fatal(_("can't read `%s': %s\n"), seed_file_name,strerror(errno) );
	close(fd);
	return 0;
	}

	close(fd);

	add_randomness( buffer, POOLSIZE, 0 );
	/* add some minor entropy to the pool now (this will also force a mixing) */
	{ pid_t x = getpid();
	add_randomness( &x, sizeof(x), 0 );
	}
	{ time_t x = time(NULL);
	add_randomness( &x, sizeof(x), 0 );
	}
	{ clock_t x = clock();
	add_randomness( &x, sizeof(x), 0 );
	}
	/* And read a few bytes from our entropy source. By using
	* a level of 0 this will not block and might not return anything
	* with some entropy drivers, however the rndlinux driver will use
	* /dev/urandom and return some stuff - Do not read to much as we
	* want to be friendly to the scare system entropy resource. */
	read_random_source( 0, 16, 0 );

	allow_seed_file_update = 1;
	return 1;
	}

	void
	_gcry_update_random_seed_file()
	{
	ulong sp, dp;
	int fd, i;
	int err;

	if ( !seed_file_name \|\| !is_initialized \|\| !pool_filled )
	return;
	if ( !allow_seed_file_update )
	{
	log_info(_("note: random_seed file not updated\n"));
	return;
	}

	err = ath_mutex_lock (&pool_lock);
	if (err)
	log_fatal ("failed to acquire the pool lock: %s\n", strerror (err));
	pool_is_locked = 1;

	/* copy the entropy pool to a scratch pool and mix both of them */
	for (i=0,dp=(ulong)keypool, sp=(ulong)rndpool;
	i < POOLWORDS; i++, dp++, sp++ )
	{
	dp = sp + ADD_VALUE;
	}
	mix_pool(rndpool); rndstats.mixrnd++;
	mix_pool(keypool); rndstats.mixkey++;

	#ifdef HAVE_DOSISH_SYSTEM
	fd = open (seed_file_name, O_WRONLY\|O_CREAT\|O_TRUNC\|O_BINARY,
	S_IRUSR\|S_IWUSR );
	#else
	fd = open (seed_file_name, O_WRONLY\|O_CREAT\|O_TRUNC, S_IRUSR\|S_IWUSR );
	#endif

	if (fd == -1 )
	log_info (_("can't create `%s': %s\n"), seed_file_name, strerror(errno) );
	else
	{
	do {
	i = write (fd, keypool, POOLSIZE );
	} while( i == -1 && errno == EINTR );
	if (i != POOLSIZE)
	log_info(_("can't write `%s': %s\n"), seed_file_name, strerror(errno) );
	if (close(fd))
	log_info(_("can't close `%s': %s\n"), seed_file_name, strerror(errno) );
	}

	pool_is_locked = 0;
	err = ath_mutex_unlock (&pool_lock);
	if (err)
	log_fatal ("failed to release the pool lock: %s\n", strerror (err));
	}


	static void
	read_pool( byte *buffer, size_t length, int level )
	{
	int i;
	ulong sp, dp;

	assert (pool_is_locked);
	if( length > POOLSIZE ) {
	log_bug("too many random bits requested\n");
	}

	if( !pool_filled ) {
	if( read_seed_file() )
	pool_filled = 1;
	}

	/* For level 2 quality (key generation) we always make
	* sure that the pool has been seeded enough initially */
	if( level == 2 && !did_initial_extra_seeding ) {
	size_t needed;

	pool_balance = 0;
	needed = length - pool_balance;
	if( needed < POOLSIZE/2 )
	needed = POOLSIZE/2;
	else if( needed > POOLSIZE )
	BUG();
	read_random_source( 3, needed, 2 );
	pool_balance += needed;
	did_initial_extra_seeding=1;
	}

	/* for level 2 make sure that there is enough random in the pool */
	if( level == 2 && pool_balance < length ) {
	size_t needed;

	if( pool_balance < 0 )
	pool_balance = 0;
	needed = length - pool_balance;
	if( needed > POOLSIZE )
	BUG();
	read_random_source( 3, needed, 2 );
	pool_balance += needed;
	}

	/* make sure the pool is filled */
	while( !pool_filled )
	random_poll();

	/* always do a fast random poll - we have to use the unlocked version*/
	do_fast_random_poll();

	if( !level ) { /* no need for cryptographic strong random */
	/* create a new pool */
	for(i=0,dp=(ulong)keypool, sp=(ulong)rndpool;
	i < POOLWORDS; i++, dp++, sp++ )
	dp = sp + ADD_VALUE;
	/* must mix both pools */
	mix_pool(rndpool); rndstats.mixrnd++;
	mix_pool(keypool); rndstats.mixkey++;
	memcpy( buffer, keypool, length );
	}
	else {
	/* mix the pool (if add_randomness() didn't it) */
	if( !just_mixed ) {
	mix_pool(rndpool);
	rndstats.mixrnd++;
	}
	/* create a new pool */
	for(i=0,dp=(ulong)keypool, sp=(ulong)rndpool;
	i < POOLWORDS; i++, dp++, sp++ )
	dp = sp + ADD_VALUE;
	/* and mix both pools */
	mix_pool(rndpool); rndstats.mixrnd++;
	mix_pool(keypool); rndstats.mixkey++;
	/* read the required data
	* we use a readpoiter to read from a different postion each
	* time */
	while( length-- ) {
	*buffer++ = keypool[pool_readpos++];
	if( pool_readpos >= POOLSIZE )
	pool_readpos = 0;
	pool_balance--;
	}
	if( pool_balance < 0 )
	pool_balance = 0;
	/* and clear the keypool */
	memset( keypool, 0, POOLSIZE );
	}
	}


	/****************
	* Add LENGTH bytes of randomness from buffer to the pool.
	* source may be used to specify the randomness source.
	* Source is:
	* 0 - used ony for initialization
	* 1 - fast random poll function
	* 2 - normal poll function
	* 3 - used when level 2 random quality has been requested
	* to do an extra pool seed.
	*/
	static void
	add_randomness( const void *buffer, size_t length, int source )
	{
	const byte *p = buffer;

	assert (pool_is_locked);
	if( !is_initialized )
	initialize();
	rndstats.addbytes += length;
	rndstats.naddbytes++;
	while( length-- ) {
	rndpool[pool_writepos++] ^= *p++;
	if( pool_writepos >= POOLSIZE ) {
	if( source > 1 )
	pool_filled = 1;
	pool_writepos = 0;
	mix_pool(rndpool); rndstats.mixrnd++;
	just_mixed = !length;
	}
	}
	}



	static void
	random_poll()
	{
	rndstats.slowpolls++;
	read_random_source( 2, POOLSIZE/5, 1 );
	}



	static void
	do_fast_random_poll ()
	{
	static void (fnc)( void ()(const void*, size_t, int), int) = NULL;
	static int initialized = 0;

	assert (pool_is_locked);
	rndstats.fastpolls++;
	if( !initialized ) {
	if( !is_initialized )
	initialize();
	initialized = 1;
	fnc = _gcry_dynload_getfnc_fast_random_poll();
	}
	if( fnc ) {
	(*fnc)( add_randomness, 1 );
	return;
	}

	/* fall back to the generic function */
	#if HAVE_GETHRTIME
	{ hrtime_t tv;
	tv = gethrtime();
	add_randomness( &tv, sizeof(tv), 1 );
	}
	#elif HAVE_GETTIMEOFDAY
	{ struct timeval tv;
	if( gettimeofday( &tv, NULL ) )
	BUG();
	add_randomness( &tv.tv_sec, sizeof(tv.tv_sec), 1 );
	add_randomness( &tv.tv_usec, sizeof(tv.tv_usec), 1 );
	}
	#elif HAVE_CLOCK_GETTIME
	{ struct timespec tv;
	if( clock_gettime( CLOCK_REALTIME, &tv ) == -1 )
	BUG();
	add_randomness( &tv.tv_sec, sizeof(tv.tv_sec), 1 );
	add_randomness( &tv.tv_nsec, sizeof(tv.tv_nsec), 1 );
	}
	#else /* use times */
	#ifndef HAVE_DOSISH_SYSTEM
	{ struct tms buf;
	times( &buf );
	add_randomness( &buf, sizeof buf, 1 );
	}
	#endif
	#endif
	#ifdef HAVE_GETRUSAGE
	#ifndef RUSAGE_SELF
	#ifdef __GCC__
	#warning There is no RUSAGE_SELF on this system
	#endif
	#else
	{
	struct rusage buf;
	/* QNX/Neutrino does return ENOSYS - so we just ignore it and
	* add whatever is in buf. In a chroot environment it might not
	* work at all (i.e. because /proc/ is not accessible), so we better
	* ugnore all error codes and hope for the best
	*/
	getrusage (RUSAGE_SELF, &buf );
	add_randomness( &buf, sizeof buf, 1 );
	memset( &buf, 0, sizeof buf );
	}
	#endif
	#endif
	/* time and clock are availabe on all systems - so
	* we better do it just in case one of the above functions
	* didn't work */
	{ time_t x = time(NULL);
	add_randomness( &x, sizeof(x), 1 );
	}
	{ clock_t x = clock();
	add_randomness( &x, sizeof(x), 1 );
	}
	}


	void
	_gcry_fast_random_poll()
	{
	int err;

	/* We have to make sure that the intialization is done because this
	gatherer might be called before any other functions and it is not
	sufficient to initialize it within do_fast_random_pool becuase we
	want to use the mutex here. FIXME: Whe should initialize the mutex
	using a global constructor independent from the initialization
	of the pool. */
	if (!is_initialized)
	initialize ();
	err = ath_mutex_lock (&pool_lock);
	if (err)
	log_fatal ("failed to acquire the pool lock: %s\n", strerror (err));
	pool_is_locked = 1;
	do_fast_random_poll ();
	pool_is_locked = 0;
	err = ath_mutex_unlock (&pool_lock);
	if (err)
	log_fatal ("failed to acquire the pool lock: %s\n", strerror (err));

	}



	static void
	read_random_source( int requester, size_t length, int level )
	{
	static int (fnc)(void ()(const void*, size_t, int), int,
	size_t, int) = NULL;
	if( !fnc ) {
	if( !is_initialized )
	initialize();
	fnc = _gcry_dynload_getfnc_gather_random();
	if( !fnc ) {
	faked_rng = 1;
	fnc = gather_faked;
	}
	if( !requester && !length && !level )
	return; /* init only */
	}
	if( (*fnc)( add_randomness, requester, length, level ) < 0 )
	log_fatal("No way to gather entropy for the RNG\n");
	}


	static int
	gather_faked( void (add)(const void, size_t, int), int requester,
	size_t length, int level )
	{
	static int initialized=0;
	size_t n;
	char buffer, p;

	if( !initialized ) {
	log_info(_("WARNING: using insecure random number generator!!\n"));
	/* we can't use tty_printf here - do we need this function at
	all - does it really make sense or canit be viewed as a potential
	security problem ? wk 17.11.99 */
	#if 0
	tty_printf(_("The random number generator is only a kludge to let\n"
	"it run - it is in no way a strong RNG!\n\n"
	"DON'T USE ANY DATA GENERATED BY THIS PROGRAM!!\n\n"));
	#endif
	initialized=1;
	#ifdef HAVE_RAND
	srand( time(NULL)*getpid());
	#else
	srandom( time(NULL)*getpid());
	#endif
	}

	p = buffer = gcry_xmalloc( length );
	n = length;
	#ifdef HAVE_RAND
	while( n-- )
	p++ = ((unsigned)(1 + (int) (256.0rand()/(RAND_MAX+1.0)))-1);
	#else
	while( n-- )
	p++ = ((unsigned)(1 + (int) (256.0random()/(RAND_MAX+1.0)))-1);
	#endif
	add_randomness( buffer, length, requester );
	gcry_free(buffer);
	return 0; /* okay */
	}

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