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/* rndlinux.c - raw random number for OSes with /dev/random
* Copyright (C) 1998, 2001 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 General Public License as published by
* the Free Software Foundation; either version 2 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 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_GETTIMEOFDAY
#include <sys/times.h>
#endif
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#if 0
#ifdef HAVE_LINUX_RANDOM_H
#include <sys/ioctl.h>
#include <asm/types.h>
#include <linux/random.h>
#endif
#endif
#include "types.h"
#include "g10lib.h"
#include "dynload.h"
static int open_device( const char *name, int minor );
static int gather_random( void (*add)(const void*, size_t, int), int requester,
size_t length, int level );
#if 0
#ifdef HAVE_DEV_RANDOM_IOCTL
static ulong
get_entropy_count( int fd )
{
ulong count;
if( ioctl( fd, RNDGETENTCNT, &count ) == -1 )
log_fatal("ioctl(RNDGETENTCNT) failed: %s\n", strerror(errno) );
return count;
}
#endif
#endif
/****************
* Used to open the /dev/random devices (Linux, xBSD, Solaris (if it exists), ...)
*/
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) );
/* Don't check device type for better portability */
/* if( (!S_ISCHR(sb.st_mode)) && (!S_ISFIFO(sb.st_mode)) )
log_fatal("invalid random device!\n" ); */
return fd;
}
static int
gather_random( void (*add)(const void*, size_t, int), int requester,
size_t length, int level )
{
static int fd_urandom = -1;
static int fd_random = -1;
int fd;
int n;
int warn=0;
byte buffer[768];
if( level >= 2 ) {
if( fd_random == -1 )
fd_random = open_device( NAME_OF_DEV_RANDOM, 8 );
fd = fd_random;
}
else {
if( fd_urandom == -1 )
fd_urandom = open_device( NAME_OF_DEV_URANDOM, 9 );
fd = fd_urandom;
}
#if 0
#ifdef HAVE_DEV_RANDOM_IOCTL
log_info("entropy count of %d is %lu\n", fd, get_entropy_count(fd) );
#endif
#endif
while( length ) {
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)) ) {
#warning FIXME: Replace fprintf by a callback
if( !warn )
fprintf(stderr,
_("\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 ) {
fprintf(stderr, "select() error: %s\n", strerror(errno));
continue;
}
do {
int nbytes = length < sizeof(buffer)? length : sizeof(buffer);
n = read(fd, buffer, nbytes );
if( n >= 0 && n > nbytes ) {
log_error("bogus read from random device (n=%d)\n", n );
n = nbytes;
}
} while( n == -1 && errno == EINTR );
if( n == -1 )
log_fatal("read error on random device: %s\n", strerror(errno));
(*add)( buffer, n, requester );
length -= n;
}
memset(buffer, 0, sizeof(buffer) );
return 0; /* success */
}
#ifndef IS_MODULE
static
#endif
const char * const gnupgext_version = "RNDLINUX ($Revision$)";
static struct {
int class;
int version;
void *func;
} func_table[] = {
{ 40, 1, gather_random },
};
/****************
* Enumerate the names of the functions together with informations about
* this function. Set sequence to an integer with a initial value of 0 and
* do not change it.
* If what is 0 all kind of functions are returned.
* Return values: class := class of function:
* 10 = message digest algorithm info function
* 11 = integer with available md algorithms
* 20 = cipher algorithm info function
* 21 = integer with available cipher algorithms
* 30 = public key algorithm info function
* 31 = integer with available pubkey algorithms
* 40 = get gather_random function
* 41 = get fast_random_poll function
* version = interface version of the function/pointer
* (currently this is 1 for all functions)
*/
#ifndef IS_MODULE
static
#endif
void *
gnupgext_enum_func( int what, int *sequence, int *class, int *vers )
{
void *ret;
int i = *sequence;
do {
if ( i >= DIM(func_table) || i < 0 ) {
return NULL;
}
*class = func_table[i].class;
*vers = func_table[i].version;
ret = func_table[i].func;
i++;
} while ( what && what != *class );
*sequence = i;
return ret;
}
#ifndef IS_MODULE
void
_gcry_rndlinux_constructor(void)
{
_gcry_register_internal_cipher_extension( gnupgext_version,
gnupgext_enum_func );
}
#endif
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