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/* $OpenBSD: gzip.c,v 1.2 1999/10/01 01:14:38 espie Exp $ */
/*-
* Copyright (c) 1999 Marc Espie.
*
* 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 above 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 software developed by Marc Espie for the OpenBSD
* Project.
*
* THIS SOFTWARE IS PROVIDED BY THE OPENBSD PROJECT AND CONTRIBUTORS
* ``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 OPENBSD
* PROJECT 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.
*/
#include <sys/types.h>
#include <sys/wait.h>
#include <stdio.h>
#include <string.h>
#include "stand.h"
#include "gzip.h"
#include "pgp.h"
/* For now, signatures follow a hardcoded format
(endianess was chosen to conform to gzip header format)
*/
static char tagsign[] =
{'S', 'i', 'g', 'P', 'G', 'P',
(char)(SIGNSIZE /256), (char)(SIGNSIZE & 255) };
/* retrieve a gzip header, including PGP signatures */
int
gzip_read_header(f, h, sign)
FILE *f;
struct mygzip_header *h;
char sign[];
{
{
int c, d;
c = fgetc(f);
d = fgetc(f);
if ((unsigned char)c != (unsigned char)GZIP_MAGIC0
|| (unsigned char)d != (unsigned char)GZIP_MAGIC1)
return GZIP_NOT_GZIP;
}
{
int method, flags;
method = fgetc(f);
flags = fgetc(f);
if (method == EOF || flags == EOF || fread(h->stamp, 1, 6, f) != 6)
return GZIP_NOT_GZIP;
h->method = (char)method;
h->flags = (char)flags;
}
if ((h->flags & CONTINUATION) != 0)
if (fread(h->part, 1, 2, f) != 2)
return GZIP_NOT_GZIP;
if ((h->flags & EXTRA_FIELD) != 0) {
char match[sizeof(tagsign)];
unsigned int len;
int c;
c = fgetc(f);
if (c == EOF)
return GZIP_NOT_PGPSIGNED;
len = (unsigned)c;
c = fgetc(f);
if (c == EOF)
return GZIP_NOT_PGPSIGNED;
len |= ((unsigned) c) << 8;
if (len != sizeof(tagsign) + SIGNSIZE)
return GZIP_NOT_PGPSIGNED;
if (fread(match, 1, sizeof(match), f) != sizeof(match) ||
memcmp(match, tagsign, sizeof(match)) != 0)
return GZIP_NOT_PGPSIGNED;
if (sign != NULL) {
if (fread(sign, 1, SIGNSIZE, f) == SIGNSIZE)
return GZIP_SIGNED;
else
return GZIP_NOT_PGPSIGNED;
} else {
if (fseek(f, SIGNSIZE, SEEK_CUR) != -1)
return GZIP_SIGNED;
else
return GZIP_NOT_PGPSIGNED;
}
} else
return GZIP_UNSIGNED;
}
/* write a gzip header, including PGP signature */
int
gzip_write_header(f, h, sign)
FILE *f;
const struct mygzip_header *h;
const char sign[];
{
char flags;
flags = h->flags;
if (sign != NULL)
flags |= EXTRA_FIELD;
else
flags &= ~EXTRA_FIELD;
if (fputc(GZIP_MAGIC0, f) == EOF ||
fputc(GZIP_MAGIC1, f) == EOF ||
fputc(h->method, f) == EOF ||
fputc(flags, f) == EOF ||
fwrite(h->stamp, 1, 6, f) != 6)
return 0;
if ((h->flags & CONTINUATION) != 0)
if (fwrite(h->part, 1, 2, f) != 2)
return 0;
if (sign != NULL) {
unsigned short len = sizeof(tagsign) + SIGNSIZE;
if (fputc(len & 255, f) == EOF ||
fputc(len/256, f) == EOF ||
fwrite(tagsign, 1, sizeof(tagsign), f) != sizeof(tagsign) ||
fwrite(sign, 1, SIGNSIZE, f) != SIGNSIZE)
return 0;
}
return 1;
}
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