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/* keybox-file.c - file oeprations
* Copyright (C) 2001, 2003 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 <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include "keybox-defs.h"
/* Read a block at the current postion and return it in r_blob.
r_blob may be NULL to simply skip the current block */
int
_keybox_read_blob (KEYBOXBLOB *r_blob, FILE *fp)
{
char *image;
size_t imagelen = 0;
int c1, c2, c3, c4, type;
int rc;
off_t off;
again:
*r_blob = NULL;
off = ftello (fp);
if (off == (off_t)-1)
return gpg_error (gpg_err_code_from_errno (errno));
if ((c1 = getc (fp)) == EOF
|| (c2 = getc (fp)) == EOF
|| (c3 = getc (fp)) == EOF
|| (c4 = getc (fp)) == EOF
|| (type = getc (fp)) == EOF)
{
if ( c1 == EOF && !ferror (fp) )
return -1; /* eof */
return gpg_error (gpg_err_code_from_errno (errno));
}
imagelen = (c1 << 24) | (c2 << 16) | (c3 << 8 ) | c4;
if (imagelen > 500000) /* sanity check */
return gpg_error (GPG_ERR_TOO_LARGE);
if (imagelen < 5)
return gpg_error (GPG_ERR_TOO_SHORT);
if (!type)
{
/* special treatment for empty blobs. */
if (fseek (fp, imagelen-5, SEEK_CUR))
return gpg_error (gpg_err_code_from_errno (errno));
goto again;
}
image = xtrymalloc (imagelen);
if (!image)
return gpg_error (gpg_err_code_from_errno (errno));
image[0] = c1; image[1] = c2; image[2] = c3; image[3] = c4; image[4] = type;
if (fread (image+5, imagelen-5, 1, fp) != 1)
{
gpg_error_t tmperr = gpg_error (gpg_err_code_from_errno (errno));
xfree (image);
return tmperr;
}
rc = r_blob? _keybox_new_blob (r_blob, image, imagelen, off) : 0;
if (rc || !r_blob)
xfree (image);
return rc;
}
/* Write the block to the current file position */
int
_keybox_write_blob (KEYBOXBLOB blob, FILE *fp)
{
const char *image;
size_t length;
image = _keybox_get_blob_image (blob, &length);
if (fwrite (image, length, 1, fp) != 1)
return gpg_error (gpg_err_code_from_errno (errno));
return 0;
}
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