openssl/crypto/rand/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)
	{
	/* If bytes >= 0, read up to 'bytes' bytes.
	 * if bytes == -1, read complete file. */

	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);
	if (i < 0) return(0);
	if (bytes == 0) return(ret);

	in=fopen(file,"rb");
	if (in == NULL) goto err;
	for (;;)
		{
		if (bytes > 0)
			n = (bytes < BUFSIZE)?(int)bytes:BUFSIZE;
		else
			n = 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;
		if (bytes > 0)
			{
			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,err=0;
	FILE *out = NULL;
	int n;

#ifdef VMS
	/* 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. */
	out=fopen(file,"rb+");
	if (out == NULL && errno != ENOENT)
		goto err;
#endif

	if (out == NULL)
		{
#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;
		if (RAND_bytes(buf,i) <= 0)
			err=1;
		i=fwrite(buf,1,i,out);
		if (i <= 0)
			{
			ret=0;
			break;
			}
		ret+=i;
		if (n <= 0) break;
		}
#ifdef VMS
	/* We may have updated an existing file using mode "rb+",
	 * now remove any old extra bytes */
	if (ret > 0)
		ftruncate(fileno(out), ret);
#endif

	fclose(out);
	memset(buf,0,BUFSIZE);
err:
	return(err ? -1 : ret);
	}

const 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);
	}