320 lines
6.9 KiB
C
320 lines
6.9 KiB
C
/* $OpenBSD: gzip.c,v 1.3 1999/10/04 21:46:28 espie Exp $ */
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/*-
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* Copyright (c) 1999 Marc Espie.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by Marc Espie for the OpenBSD
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* Project.
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*
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* THIS SOFTWARE IS PROVIDED BY THE OPENBSD PROJECT AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OPENBSD
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* PROJECT OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/types.h>
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#include <sys/wait.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <assert.h>
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#include <string.h>
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#include "stand.h"
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#include "gzip.h"
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#include "pgp.h"
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/*
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* Signatures follow a simple format
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* (endianess was chosen to conform to gzip header format)
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*/
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SIGNTAG known_tags[KNOWN_TAGS] = {
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{'S', 'I', 'G', 'P', 'G', 'P', 0, 0 },
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{'C', 'K', 'S', 'H', 'A', '1', 0, 0 },
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{'C', 'R', 'X', '5', '0', '9', 0, 0 },
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{'S', 'i', 'g', 'P', 'G', 'P', 0, 0 } /* old format */
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};
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void
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sign_fill_tag(sign)
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struct signature *sign;
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{
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sign->tag[6] = sign->length % 256;
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sign->tag[7] = sign->length / 256;
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}
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void
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sign_fill_length(sign)
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struct signature *sign;
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{
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sign->length = sign->tag[6] + 256 * sign->tag[7];
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}
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static size_t
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stack_sign(match, t, f, sign)
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SIGNTAG match;
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int t;
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FILE *f;
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struct signature **sign;
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{
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struct signature *new_sign;
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size_t length;
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new_sign = malloc(sizeof *new_sign);
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if (new_sign == NULL)
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return 0;
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new_sign->type = t;
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new_sign->next = NULL;
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memcpy(new_sign->tag, match, sizeof(SIGNTAG));
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sign_fill_length(new_sign);
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new_sign->data = malloc(new_sign->length);
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if (new_sign->data == NULL ||
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fread(new_sign->data, 1, new_sign->length, f) != new_sign->length) {
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free_signature(new_sign);
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return 0;
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}
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length = new_sign->length;
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if (sign != NULL) {
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if (!*sign)
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*sign = new_sign;
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else {
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while ((*sign)->next != NULL)
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sign = &((*sign)->next);
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(*sign)->next = new_sign;
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}
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} else
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free_signature(new_sign);
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return length;
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}
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static int
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add_sign(f, sign)
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FILE *f;
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struct signature **sign;
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{
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SIGNTAG match;
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int i;
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if (fread(match, 1, sizeof(SIGNTAG), f) != sizeof(SIGNTAG))
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return -1;
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for (i = 0; i < KNOWN_TAGS; i++) {
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if (memcmp(match, known_tags[i], TAGCHECK) == 0) {
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unsigned int sign_length = stack_sign(match, i, f, sign);
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if (sign_length > 0)
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return sign_length + sizeof(SIGNTAG);
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else
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return -1;
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}
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}
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return 0;
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}
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static int
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gzip_magic(f)
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FILE *f;
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{
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int c, d;
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c = fgetc(f);
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d = fgetc(f);
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if ((unsigned char)c != (unsigned char)GZIP_MAGIC0
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|| (unsigned char)d != (unsigned char)GZIP_MAGIC1)
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return 0;
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else
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return 1;
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}
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static int
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fill_gzip_fields(f, h)
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FILE *f;
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struct mygzip_header *h;
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{
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int method, flags;
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method = fgetc(f);
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flags = fgetc(f);
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if (method == EOF || flags == EOF || fread(h->stamp, 1, 6, f) != 6)
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return 0;
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h->method = (char)method;
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h->flags = (char)flags;
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if ((h->flags & CONTINUATION) != 0)
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if (fread(h->part, 1, 2, f) != 2)
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return 0;
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return 1;
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}
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/* retrieve a gzip header, including signatures */
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int
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gzip_read_header(f, h, sign)
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FILE *f;
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struct mygzip_header *h;
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struct signature **sign;
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{
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if (sign != NULL)
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*sign = NULL;
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if (!gzip_magic(f) || !fill_gzip_fields(f, h))
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return GZIP_NOT_GZIP;
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if ((h->flags & EXTRA_FIELD) == 0) {
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h->remaining = 0;
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return GZIP_UNSIGNED;
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}
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else {
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int c;
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c = fgetc(f);
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if (c == EOF)
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return GZIP_NOT_GZIP;
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h->remaining = (unsigned)c;
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c = fgetc(f);
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if (c == EOF)
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return GZIP_NOT_PGPSIGNED;
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h->remaining += ((unsigned) c) << 8;
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while (h->remaining >= sizeof(SIGNTAG)) {
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int sign_length = add_sign(f, sign);
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if (sign_length > 0)
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h->remaining -= sign_length;
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if (sign_length < 0)
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return GZIP_NOT_GZIP;
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if (sign_length == 0)
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return GZIP_SIGNED;
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}
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return GZIP_SIGNED;
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}
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}
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static unsigned
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sign_length(sign)
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struct signature *sign;
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{
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unsigned total = 0;
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while (sign != NULL) {
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total += sizeof(SIGNTAG) + sign->length;
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sign = sign->next;
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}
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return total;
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}
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struct mydata {
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FILE *file;
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int ok;
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};
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static void myadd(arg, buffer, size)
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void *arg;
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const char *buffer;
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size_t size;
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{
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struct mydata *d = arg;
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if (fwrite(buffer, 1, size, d->file) == size)
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d->ok = 1;
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else
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d->ok = 0;
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}
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/* write a gzip header, including signatures */
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int
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gzip_write_header(f, h, sign)
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FILE *f;
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const struct mygzip_header *h;
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struct signature *sign;
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{
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struct mydata d;
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d.file = f;
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if (gzip_copy_header(h, sign, myadd, &d) == 0)
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return 0;
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return d.ok;
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}
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int
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gzip_copy_header(h, sign, add, data)
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const struct mygzip_header *h;
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struct signature *sign;
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void (*add)(void *, const char *, size_t);
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void *data;
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{
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char flags;
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size_t length;
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size_t buflength;
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size_t i;
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char *buffer;
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length = h->remaining + sign_length(sign);
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if (length) {
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buflength = length + 2;
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flags = h->flags | EXTRA_FIELD;
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} else {
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flags = h->flags & ~EXTRA_FIELD;
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buflength = 0;
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}
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buflength += 10;
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if ((h->flags & CONTINUATION) != 0)
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buflength += 2;
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buffer = malloc(buflength);
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if (buffer == NULL)
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return 0;
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i = 0;
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buffer[i++] = GZIP_MAGIC0;
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buffer[i++] = GZIP_MAGIC1;
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buffer[i++] = h->method;
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buffer[i++] = flags;
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memcpy(buffer+i, h->stamp, 6);
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i += 6;
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if ((flags & CONTINUATION) != 0) {
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memcpy(buffer+i, h->part, 2);
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i += 2;
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}
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if (length) {
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buffer[i++] = (char)(length % 256);
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buffer[i++] = (char)(length / 256);
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while (sign != NULL) {
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memcpy(buffer+i, sign->tag, sizeof(SIGNTAG));
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i += sizeof(SIGNTAG);
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memcpy(buffer+i, sign->data, sign->length);
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i += sign->length;
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sign = sign->next;
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}
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}
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(*add)(data, buffer, buflength);
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free(buffer);
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return 1;
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}
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void
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free_signature(sign)
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struct signature *sign;
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{
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struct signature *next;
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while (sign != NULL) {
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next = sign->next;
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free(sign->data);
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free(sign);
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sign = next;
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}
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}
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