postgresql/contrib/pgcrypto/pgp-compress.c
Michael Paquier 8a15e735be Fix some grammar and typos in comments and docs
The documentation fixes are backpatched down to where they apply.

Author: Justin Pryzby
Discussion: https://postgr.es/m/20201031020801.GD3080@telsasoft.com
Backpatch-through: 9.6
2020-11-02 15:14:41 +09:00

347 lines
7.4 KiB
C

/*
* pgp-compress.c
* ZIP and ZLIB compression via zlib.
*
* Copyright (c) 2005 Marko Kreen
* All rights reserved.
*
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 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.
*
* contrib/pgcrypto/pgp-compress.c
*/
#include "postgres.h"
#include "pgp.h"
#include "px.h"
/*
* Compressed pkt writer
*/
#ifdef HAVE_LIBZ
#include <zlib.h>
#define ZIP_OUT_BUF 8192
#define ZIP_IN_BLOCK 8192
struct ZipStat
{
uint8 type;
int buf_len;
int hdr_done;
z_stream stream;
uint8 buf[ZIP_OUT_BUF];
};
static void *
z_alloc(void *priv, unsigned n_items, unsigned item_len)
{
return palloc(n_items * item_len);
}
static void
z_free(void *priv, void *addr)
{
pfree(addr);
}
static int
compress_init(PushFilter *next, void *init_arg, void **priv_p)
{
int res;
struct ZipStat *st;
PGP_Context *ctx = init_arg;
uint8 type = ctx->compress_algo;
if (type != PGP_COMPR_ZLIB && type != PGP_COMPR_ZIP)
return PXE_PGP_UNSUPPORTED_COMPR;
/*
* init
*/
st = palloc0(sizeof(*st));
st->buf_len = ZIP_OUT_BUF;
st->stream.zalloc = z_alloc;
st->stream.zfree = z_free;
if (type == PGP_COMPR_ZIP)
res = deflateInit2(&st->stream, ctx->compress_level,
Z_DEFLATED, -15, 8, Z_DEFAULT_STRATEGY);
else
res = deflateInit(&st->stream, ctx->compress_level);
if (res != Z_OK)
{
pfree(st);
return PXE_PGP_COMPRESSION_ERROR;
}
*priv_p = st;
return ZIP_IN_BLOCK;
}
/* writes compressed data packet */
/* can handle zero-len incoming data, but shouldn't */
static int
compress_process(PushFilter *next, void *priv, const uint8 *data, int len)
{
int res,
n_out;
struct ZipStat *st = priv;
/*
* process data
*/
st->stream.next_in = unconstify(uint8 *, data);
st->stream.avail_in = len;
while (st->stream.avail_in > 0)
{
st->stream.next_out = st->buf;
st->stream.avail_out = st->buf_len;
res = deflate(&st->stream, Z_NO_FLUSH);
if (res != Z_OK)
return PXE_PGP_COMPRESSION_ERROR;
n_out = st->buf_len - st->stream.avail_out;
if (n_out > 0)
{
res = pushf_write(next, st->buf, n_out);
if (res < 0)
return res;
}
}
return 0;
}
static int
compress_flush(PushFilter *next, void *priv)
{
int res,
zres,
n_out;
struct ZipStat *st = priv;
st->stream.next_in = NULL;
st->stream.avail_in = 0;
while (1)
{
st->stream.next_out = st->buf;
st->stream.avail_out = st->buf_len;
zres = deflate(&st->stream, Z_FINISH);
if (zres != Z_STREAM_END && zres != Z_OK)
return PXE_PGP_COMPRESSION_ERROR;
n_out = st->buf_len - st->stream.avail_out;
if (n_out > 0)
{
res = pushf_write(next, st->buf, n_out);
if (res < 0)
return res;
}
if (zres == Z_STREAM_END)
break;
}
return 0;
}
static void
compress_free(void *priv)
{
struct ZipStat *st = priv;
deflateEnd(&st->stream);
px_memset(st, 0, sizeof(*st));
pfree(st);
}
static const PushFilterOps
compress_filter = {
compress_init, compress_process, compress_flush, compress_free
};
int
pgp_compress_filter(PushFilter **res, PGP_Context *ctx, PushFilter *dst)
{
return pushf_create(res, &compress_filter, ctx, dst);
}
/*
* Decompress
*/
struct DecomprData
{
int buf_len; /* = ZIP_OUT_BUF */
int buf_data; /* available data */
uint8 *pos;
z_stream stream;
int eof;
uint8 buf[ZIP_OUT_BUF];
};
static int
decompress_init(void **priv_p, void *arg, PullFilter *src)
{
PGP_Context *ctx = arg;
struct DecomprData *dec;
int res;
if (ctx->compress_algo != PGP_COMPR_ZLIB
&& ctx->compress_algo != PGP_COMPR_ZIP)
return PXE_PGP_UNSUPPORTED_COMPR;
dec = palloc0(sizeof(*dec));
dec->buf_len = ZIP_OUT_BUF;
*priv_p = dec;
dec->stream.zalloc = z_alloc;
dec->stream.zfree = z_free;
if (ctx->compress_algo == PGP_COMPR_ZIP)
res = inflateInit2(&dec->stream, -15);
else
res = inflateInit(&dec->stream);
if (res != Z_OK)
{
pfree(dec);
px_debug("decompress_init: inflateInit error");
return PXE_PGP_COMPRESSION_ERROR;
}
return 0;
}
static int
decompress_read(void *priv, PullFilter *src, int len,
uint8 **data_p, uint8 *buf, int buflen)
{
int res;
int flush;
struct DecomprData *dec = priv;
restart:
if (dec->buf_data > 0)
{
if (len > dec->buf_data)
len = dec->buf_data;
*data_p = dec->pos;
dec->pos += len;
dec->buf_data -= len;
return len;
}
if (dec->eof)
return 0;
if (dec->stream.avail_in == 0)
{
uint8 *tmp;
res = pullf_read(src, 8192, &tmp);
if (res < 0)
return res;
dec->stream.next_in = tmp;
dec->stream.avail_in = res;
}
dec->stream.next_out = dec->buf;
dec->stream.avail_out = dec->buf_len;
dec->pos = dec->buf;
/*
* Z_SYNC_FLUSH is tell zlib to output as much as possible. It should do
* it anyway (Z_NO_FLUSH), but seems to reserve the right not to. So lets
* follow the API.
*/
flush = dec->stream.avail_in ? Z_SYNC_FLUSH : Z_FINISH;
res = inflate(&dec->stream, flush);
if (res != Z_OK && res != Z_STREAM_END)
{
px_debug("decompress_read: inflate error: %d", res);
return PXE_PGP_CORRUPT_DATA;
}
dec->buf_data = dec->buf_len - dec->stream.avail_out;
if (res == Z_STREAM_END)
{
uint8 *tmp;
/*
* A stream must be terminated by a normal packet. If the last stream
* packet in the source stream is a full packet, a normal empty packet
* must follow. Since the underlying packet reader doesn't know that
* the compressed stream has been ended, we need to consume the
* terminating packet here. This read does not harm even if the
* stream has already ended.
*/
res = pullf_read(src, 1, &tmp);
if (res < 0)
return res;
else if (res > 0)
{
px_debug("decompress_read: extra bytes after end of stream");
return PXE_PGP_CORRUPT_DATA;
}
dec->eof = 1;
}
goto restart;
}
static void
decompress_free(void *priv)
{
struct DecomprData *dec = priv;
inflateEnd(&dec->stream);
px_memset(dec, 0, sizeof(*dec));
pfree(dec);
}
static const PullFilterOps
decompress_filter = {
decompress_init, decompress_read, decompress_free
};
int
pgp_decompress_filter(PullFilter **res, PGP_Context *ctx, PullFilter *src)
{
return pullf_create(res, &decompress_filter, ctx, src);
}
#else /* !HAVE_LIBZ */
int
pgp_compress_filter(PushFilter **res, PGP_Context *ctx, PushFilter *dst)
{
return PXE_PGP_UNSUPPORTED_COMPR;
}
int
pgp_decompress_filter(PullFilter **res, PGP_Context *ctx, PullFilter *src)
{
return PXE_PGP_UNSUPPORTED_COMPR;
}
#endif