randfile.c

/* crypto/rand/randfile.c */
/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
 * All rights reserved.
 *
 * This package is an SSL implementation written
 * by Eric Young (eay@cryptsoft.com).
 * The implementation was written so as to conform with Netscapes SSL.
 * 
 * This library is free for commercial and non-commercial use as long as
 * the following conditions are aheared to.  The following conditions
 * apply to all code found in this distribution, be it the RC4, RSA,
 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
 * included with this distribution is covered by the same copyright terms
 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
 * 
 * Copyright remains Eric Young's, and as such any Copyright notices in
 * the code are not to be removed.
 * If this package is used in a product, Eric Young should be given attribution
 * as the author of the parts of the library used.
 * This can be in the form of a textual message at program startup or
 * in documentation (online or textual) provided with the package.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *    "This product includes cryptographic software written by
 *     Eric Young (eay@cryptsoft.com)"
 *    The word 'cryptographic' can be left out if the rouines from the library
 *    being used are not cryptographic related :-).
 * 4. If you include any Windows specific code (or a derivative thereof) from 
 *    the apps directory (application code) you must include an acknowledgement:
 *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
 * 
 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * 
 * The licence and distribution terms for any publically available version or
 * derivative of this code cannot be changed.  i.e. this code cannot simply be
 * copied and put under another distribution licence
 * [including the GNU Public Licence.]
 */

#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "openssl/e_os.h"

#ifndef NO_SYS_TYPES_H
# include <sys/types.h>
#endif
#ifdef MAC_OS_pre_X
# include <stat.h>
#else
# include <sys/stat.h>
#endif

#include <openssl/rand.h>

#undef BUFSIZE
#define BUFSIZE	1024
#define RAND_DATA 1024

/* #define RFILE ".rnd" - defined in ../../e_os.h */

int RAND_load_file(const char *file, long bytes)
	{
	MS_STATIC unsigned char buf[BUFSIZE];
	struct stat sb;
	int i,ret=0,n;
	FILE *in;

	if (file == NULL) return(0);

	i=stat(file,&sb);
	/* If the state fails, put some crap in anyway */
	RAND_add(&sb,sizeof(sb),0);
	ret+=sizeof(sb);
	if (i < 0) return(0);
	if (bytes <= 0) return(ret);

	in=fopen(file,"rb");
	if (in == NULL) goto err;
	for (;;)
		{
		n=(bytes < BUFSIZE)?(int)bytes:BUFSIZE;
		i=fread(buf,1,n,in);
		if (i <= 0) break;
		/* even if n != i, use the full array */
		RAND_add(buf,n,i);
		ret+=i;
		bytes-=n;
		if (bytes <= 0) break;
		}
	fclose(in);
	memset(buf,0,BUFSIZE);
err:
	return(ret);
	}

int RAND_write_file(const char *file)
	{
	unsigned char buf[BUFSIZE];
	int i,ret=0;
	FILE *out = NULL;
	int n;

	/* Under VMS, fopen(file, "wb") will create a new version of the
	   same file.  This is not good, so let's try updating an existing
	   one, and create file only if it doesn't already exist.  This
	   should be completely harmless on system that have no file
	   versions.					-- Richard Levitte */
	out=fopen(file,"rb+");
	if (out == NULL
#ifdef ENOENT
	    && errno == ENOENT
#endif
	   )
		{
		errno = 0;
#if defined O_CREAT && defined O_EXCL
		/* chmod(..., 0600) is too late to protect the file,
		 * permissions should be restrictive from the start */
		{
		    int fd = open(file, O_CREAT | O_EXCL, 0600);
		    if (fd != -1)
			out = fdopen(fd, "wb");
		}
#else		
		out=fopen(file,"wb");
#endif
		}
	if (out == NULL) goto err;
#ifndef NO_CHMOD
	chmod(file,0600);
#endif
	n=RAND_DATA;
	for (;;)
		{
		i=(n > BUFSIZE)?BUFSIZE:n;
		n-=BUFSIZE;
		RAND_bytes(buf,i);
		i=fwrite(buf,1,i,out);
		if (i <= 0)
			{
			ret=0;
			break;
			}
		ret+=i;
		if (n <= 0) break;
		}
	fclose(out);
	memset(buf,0,BUFSIZE);
err:
	return(ret);
	}

char *RAND_file_name(char *buf, int size)
	{
	char *s;
	char *ret=NULL;

	s=getenv("RANDFILE");
	if (s != NULL)
		{
		strncpy(buf,s,size-1);
		buf[size-1]='\0';
		ret=buf;
		}
	else
		{
		s=getenv("HOME");
		if (s == NULL) return(RFILE);
		if (((int)(strlen(s)+strlen(RFILE)+2)) > size)
			return(RFILE);
		strcpy(buf,s);
#ifndef VMS
		strcat(buf,"/");
#endif
		strcat(buf,RFILE);
		ret=buf;
		}
	return(ret);
	}