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rndegd.c
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/* rndegd.c - interface to the EGD
* Copyright (C) 1999, 2000, 2002, 2003 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, see <https://www.gnu.org/licenses/>.
* SPDX-License-Identifier: LGPL-2.1-or-later
*/
#include <config.h>
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <sys/time.h>
#include <sys/stat.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/un.h>
#include "types.h"
#include "g10lib.h"
#include "cipher.h"
#include "rand-internal.h"
#ifndef offsetof
#define offsetof(type, member) ((size_t) &((type *)0)->member)
#endif
static int egd_socket = -1;
/* Allocated name of the socket if supplied at runtime. */
static char *user_socket_name;
/* Allocate a new filename from FIRST_PART and SECOND_PART and to
tilde expansion for first_part. SECOND_PART might be NULL.
*/
static char *
my_make_filename (const char *first_part, const char *second_part)
{
size_t n;
char *name, *home, *p;
n = strlen(first_part)+1;
if (second_part)
n += strlen (second_part) + 1;
home = NULL;
if( *first_part == '~' && first_part[1] == '/'
&& (home = getenv("HOME")) && *home )
n += strlen(home);
name = _gcry_xmalloc(n);
p = (home
? stpcpy (stpcpy (name, home), first_part+1 )
: stpcpy (name, first_part) );
if (second_part)
strcpy (stpcpy(p,"/"), second_part);
return name;
}
static int
do_write( int fd, void *buf, size_t nbytes )
{
size_t nleft = nbytes;
int nwritten;
while( nleft > 0 )
{
nwritten = write( fd, buf, nleft);
if( nwritten < 0 )
{
if( errno == EINTR )
continue;
return -1;
}
nleft -= nwritten;
buf = (char*)buf + nwritten;
}
return 0;
}
static int
do_read( int fd, void *buf, size_t nbytes )
{
int n, nread = 0;
do
{
do
{
n = read(fd, (char*)buf + nread, nbytes );
}
while( n == -1 && errno == EINTR );
if( n == -1)
return nread? nread:-1;
if( n == 0)
return -1;
nread += n;
nbytes -= n;
}
while( nread < nbytes );
return nread;
}
/* Note that his function is not thread-safe. */
gpg_error_t
_gcry_rndegd_set_socket_name (const char *name)
{
char *newname;
struct sockaddr_un addr;
newname = my_make_filename (name, NULL);
if (strlen (newname)+1 >= sizeof addr.sun_path)
{
xfree (newname);
return gpg_error_from_syserror ();
}
xfree (user_socket_name);
user_socket_name = newname;
return 0;
}
/* Connect to the EGD and return the file descriptor. Return -1 on
error. With NOFAIL set to true, silently fail and return the
error, otherwise print an error message and die. */
int
_gcry_rndegd_connect_socket (int nofail)
{
int fd;
const char *bname = NULL;
char *name;
struct sockaddr_un addr;
int addr_len;
if (egd_socket != -1)
{
close (egd_socket);
egd_socket = -1;
}
#ifdef EGD_SOCKET_NAME
bname = EGD_SOCKET_NAME;
#endif
if (user_socket_name)
{
name = _gcry_strdup (user_socket_name);
if (!name)
{
if (!nofail)
log_fatal ("error allocating memory in rndegd: %s\n",
strerror(errno) );
return -1;
}
}
else if ( !bname || !*bname )
name = my_make_filename ("~/.gnupg", "entropy");
else
name = my_make_filename (bname, NULL);
if (strlen(name)+1 >= sizeof addr.sun_path)
log_fatal ("EGD socketname is too long\n");
memset( &addr, 0, sizeof addr );
addr.sun_family = AF_UNIX;
strcpy( addr.sun_path, name );
addr_len = (offsetof( struct sockaddr_un, sun_path )
+ strlen( addr.sun_path ));
fd = socket(AF_UNIX, SOCK_STREAM, 0);
if (fd == -1 && !nofail)
log_fatal("can't create unix domain socket: %s\n", strerror(errno) );
else if (connect (fd, (struct sockaddr*)&addr, addr_len) == -1)
{
if (!nofail)
log_fatal("can't connect to EGD socket `%s': %s\n",
name, strerror(errno) );
close (fd);
fd = -1;
}
xfree (name);
if (fd != -1)
egd_socket = fd;
return fd;
}
/****************
* Note: We always use the highest level.
* To boost the performance we may want to add some
* additional code for level 1
*
* Using a level of 0 should never block and better add nothing
* to the pool. So this is just a dummy for EGD.
*/
int
_gcry_rndegd_gather_random (void (*add)(const void*, size_t,
enum random_origins),
enum random_origins origin,
size_t length, int level )
{
int fd = egd_socket;
int n;
byte buffer[256+2];
int nbytes;
int do_restart = 0;
if( !length )
return 0;
if( !level )
return 0;
restart:
if (fd == -1 || do_restart)
fd = _gcry_rndegd_connect_socket (0);
do_restart = 0;
nbytes = length < 255? length : 255;
/* First time we do it with a non blocking request */
buffer[0] = 1; /* non blocking */
buffer[1] = nbytes;
if( do_write( fd, buffer, 2 ) == -1 )
log_fatal("can't write to the EGD: %s\n", strerror(errno) );
n = do_read( fd, buffer, 1 );
if( n == -1 )
{
log_error("read error on EGD: %s\n", strerror(errno));
do_restart = 1;
goto restart;
}
n = buffer[0];
if( n )
{
n = do_read( fd, buffer, n );
if( n == -1 )
{
log_error("read error on EGD: %s\n", strerror(errno));
do_restart = 1;
goto restart;
}
(*add)( buffer, n, origin );
length -= n;
}
if( length )
{
log_info (
_("Please wait, entropy is being gathered. Do some work if it would\n"
"keep you from getting bored, because it will improve the quality\n"
"of the entropy.\n") );
}
while( length )
{
nbytes = length < 255? length : 255;
buffer[0] = 2; /* blocking */
buffer[1] = nbytes;
if( do_write( fd, buffer, 2 ) == -1 )
log_fatal("can't write to the EGD: %s\n", strerror(errno) );
n = do_read( fd, buffer, nbytes );
if( n == -1 )
{
log_error("read error on EGD: %s\n", strerror(errno));
do_restart = 1;
goto restart;
}
(*add)( buffer, n, origin );
length -= n;
}
memset(buffer, 0, sizeof(buffer) );
return 0; /* success */
}

File Metadata

Mime Type
text/x-c
Expires
Tue, Apr 14, 9:27 PM (3 h, 54 m)
Storage Engine
local-disk
Storage Format
Raw Data
Storage Handle
6e/07/b25a420264b5897e29a37c6befec

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