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gnupg/cipher/rand-unix.c

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1998-05-13 19:53:36 +02:00
/* rand-unix.c - raw random number generator for unix like OSes
* Copyright (C) 1998 Free Software Foundation, Inc.
*
* This file is part of GNUPG.
*
* GNUPG is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* GNUPG 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 General Public License for more details.
*
* You should have received a copy of the GNU 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
*/
#include <config.h>
#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include <errno.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/stat.h>
#ifdef HAVE_GETHRTIME
#include <sys/times.h>
#endif
#ifndef HAVE_GETTIMEOFTIME
#include <sys/times.h>
#endif
#ifdef HAVE_GETRUSAGE
#include <sys/resource.h>
#endif
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include "util.h"
#include "rmd.h"
#include "ttyio.h"
#include "i18n.h"
#include "rand-internal.h"
#ifdef USE_RAND_UNIX /* This file is only for real systems */
void
random_poll()
{
char buf[POOLSIZE/5];
read_random_source( buf, POOLSIZE/5, 1 ); /* read /dev/urandom */
add_randomness( buf, POOLSIZE/5, 2);
memset( buf, 0, POOLSIZE/5);
}
void
fast_random_poll()
{
#if HAVE_GETHRTIME
{ hrtime_t tv;
tv = gethrtime(void);
add_randomness( &tv, sizeof(tv), 1 );
}
#elif HAVE_GETTIMEOFTIME
{ 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 );
}
#else /* use times */
{ struct tms buf;
times( &buf );
add_randomness( &buf, sizeof buf, 1 );
}
#endif
#ifdef HAVE_GETRUSAGE
{ struct rusage buf;
if( getrusage( RUSAGE_SELF, &buf ) )
BUG();
add_randomness( &buf, sizeof buf, 1 );
memset( &buf, 0, sizeof buf );
}
#endif
}
#ifdef HAVE_DEV_RANDOM /* we have the /dev/random device */
/****************
* Used to open the Linux /dev/random device
*/
static int
open_device( const char *name, int minor )
{
int fd;
struct stat sb;
fd = open( name, O_RDONLY );
if( fd == -1 )
log_fatal("can't open %s: %s\n", name, strerror(errno) );
if( fstat( fd, &sb ) )
log_fatal("stat() off %s failed: %s\n", name, strerror(errno) );
#if defined(__sparc__) && defined(__linux__)
#warning something is wrong with UltraPenguin /dev/random
#else
if( !S_ISCHR(sb.st_mode) )
log_fatal("invalid random device!\n" );
#endif
return fd;
}
void
read_random_source( byte *buffer, size_t length, int level )
{
static int fd_urandom = -1;
static int fd_random = -1;
int fd;
int n;
int warn=0;
if( level == 2 ) {
if( fd_random == -1 )
fd_random = open_device( "/dev/random", 8 );
fd = fd_random;
}
else {
/* fixme: we should use a simpler one for level 0,
* because reading from /dev/urandom removes entropy
* and the next read on /dev/random may have to wait */
if( fd_urandom == -1 )
fd_urandom = open_device( "/dev/urandom", 9 );
fd = fd_urandom;
}
do {
fd_set rfds;
struct timeval tv;
int rc;
FD_ZERO(&rfds);
FD_SET(fd, &rfds);
tv.tv_sec = 3;
tv.tv_usec = 0;
if( !(rc=select(fd+1, &rfds, NULL, NULL, &tv)) ) {
if( !warn )
tty_printf( _(
"\n"
"Not enough random bytes available. Please do some other work to give\n"
"the OS a chance to collect more entropy! (Need %d more bytes)\n"), length );
warn = 1;
continue;
}
else if( rc == -1 ) {
tty_printf("select() error: %s\n", strerror(errno));
continue;
}
assert( length < 500 );
do {
n = read(fd, buffer, length );
if( n >= 0 && n > length ) {
log_error("bogus read from random device (n=%d)\n", n );
n = length;
}
} while( n == -1 && errno == EINTR );
if( n == -1 )
log_fatal("read error on random device: %s\n", strerror(errno) );
assert( n <= length );
buffer += n;
length -= n;
} while( length );
}
#else /* not HAVE_DEV_RANDOM */
/****************
* The real random data collector for Unix.
* this function runs in a loop, waiting for commands from ctrl_fd
* and normally starts a collection process, which outputs random
* bytes to out_fd.
*
* Commands understand from ctrl_fd are single character:
* 'Q' = Quit the loop
* 'S' = Start a new collection process
*/
static void
collector( FILE *ctrlfp, FILE *outfp )
{
}
#endif /* no HAVE_DEV_RANDOM */
#endif /* USE_RAND_UNIX */