/* compress.c - compress filter

 * Copyright (C) 1998, 1999, 2000, 2001, 2002,

 *               2003, 2006, 2010 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 3 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, see <https://www.gnu.org/licenses/>.

 */

/* Note that the code in compress-bz2.c is nearly identical to the

   code here, so if you fix a bug here, look there to see if a

   matching bug needs to be fixed.  I tried to have one set of

   functions that could do ZIP, ZLIB, and BZIP2, but it became

   dangerously unreadable with #ifdefs and if(algo) -dshaw */

#include <config.h>

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <unistd.h>

#include <errno.h>

#ifdef HAVE_ZIP

# include <zlib.h>

#endif

#include "gpg.h"

#include "../common/util.h"

#include "packet.h"

#include "filter.h"

#include "main.h"

#include "options.h"

#ifdef __riscos__

#define BYTEF_CAST(a) ((Bytef *)(a))

#else

#define BYTEF_CAST(a) (a)

#endif

int compress_filter_bz2( void *opaque, int control,

       IOBUF a, byte *buf, size_t *ret_len);

#ifdef HAVE_ZIP

static void

init_compress( compress_filter_context_t *zfx, z_stream *zs )

{

    int rc;

    int level;

    if( opt.compress_level >= 1 && opt.compress_level <= 9 )

  level = opt.compress_level;

    else if( opt.compress_level == -1 )

  level = Z_DEFAULT_COMPRESSION;

    else {

  log_error("invalid compression level; using default level\n");

  level = Z_DEFAULT_COMPRESSION;

    }

    if( (rc = zfx->algo == 1? deflateInit2( zs, level, Z_DEFLATED,

              -13, 8, Z_DEFAULT_STRATEGY)

          : deflateInit( zs, level )

          ) != Z_OK ) {

  log_error ("zlib problem: %s\n", zs->msg? zs->msg :

             rc == Z_MEM_ERROR ? "out of core" :

             rc == Z_VERSION_ERROR ? "invalid lib version" :

                   "unknown error" );

        write_status_error ("zlib.init", gpg_error (GPG_ERR_INTERNAL));

        g10_exit (2);

    }

    zfx->outbufsize = 65536;

    zfx->outbuf = xmalloc( zfx->outbufsize );

}

static int

do_compress( compress_filter_context_t *zfx, z_stream *zs, int flush, IOBUF a )

{

    int rc;

    int zrc;

    unsigned n;

    if (flush == Z_NO_FLUSH && zs->avail_in == 0)

      return 0;

    do {

  zs->next_out = BYTEF_CAST (zfx->outbuf);

  zs->avail_out = zfx->outbufsize;

  if( DBG_FILTER )

      log_debug("enter deflate: avail_in=%u, avail_out=%u, flush=%d\n",

        (unsigned)zs->avail_in, (unsigned)zs->avail_out, flush );

  zrc = deflate( zs, flush );

  if( zrc == Z_STREAM_END && flush == Z_FINISH )

      ;

  else if( zrc != Z_OK ) {

      if( zs->msg )

    log_error ("zlib deflate problem: %s\n", zs->msg );

      else

    log_error ("zlib deflate problem: rc=%d\n", zrc );

            write_status_error ("zlib.deflate", gpg_error (GPG_ERR_INTERNAL));

            g10_exit (2);

  }

  n = zfx->outbufsize - zs->avail_out;

  if( DBG_FILTER )

      log_debug("leave deflate: "

          "avail_in=%u, avail_out=%u, n=%u, zrc=%d\n",

    (unsigned)zs->avail_in, (unsigned)zs->avail_out,

                 (unsigned)n, zrc );

  if( (rc=iobuf_write( a, zfx->outbuf, n )) ) {

      log_error ("deflate: iobuf_write failed\n");

      return rc;

  }

    } while( zs->avail_in || (flush == Z_FINISH && zrc != Z_STREAM_END) );

    return 0;

}

static void

init_uncompress( compress_filter_context_t *zfx, z_stream *zs )

{

    int rc;

    /****************

     * PGP uses a windowsize of 13 bits. Using a negative value for

     * it forces zlib not to expect a zlib header.  This is a

     * undocumented feature Peter Gutmann told me about.

     *

     * We must use 15 bits for the inflator because CryptoEx uses 15

     * bits thus the output would get scrambled w/o error indication

     * if we would use 13 bits.  For the uncompressing this does not

     * matter at all.

     */

    if( (rc = zfx->algo == 1? inflateInit2( zs, -15)

          : inflateInit( zs )) != Z_OK ) {

  log_error ("zlib problem: %s\n", zs->msg? zs->msg :

                   rc == Z_MEM_ERROR ? "out of core" :

                   rc == Z_VERSION_ERROR ? "invalid lib version" :

                                            "unknown error" );

        write_status_error ("zlib.init.un", gpg_error (GPG_ERR_INTERNAL));

        g10_exit (2);

    }

    zfx->inbufsize = 2048;

    zfx->inbuf = xmalloc( zfx->inbufsize );

    zs->avail_in = 0;

}

static int

do_uncompress( compress_filter_context_t *zfx, z_stream *zs,

         IOBUF a, size_t *ret_len )

{

    int zrc;

    int rc = 0;

    int leave = 0;

    size_t n;

    int nread, count;

    int refill = !zs->avail_in;

    if( DBG_FILTER )

  log_debug("begin inflate: avail_in=%u, avail_out=%u, inbuf=%u\n",

    (unsigned)zs->avail_in, (unsigned)zs->avail_out,

    (unsigned)zfx->inbufsize );

    do {

  if( zs->avail_in < zfx->inbufsize && refill ) {

      n = zs->avail_in;

      if( !n )

            zs->next_in = BYTEF_CAST (zfx->inbuf);

      count = zfx->inbufsize - n;

      nread = iobuf_read( a, zfx->inbuf + n, count );

      if( nread == -1 ) nread = 0;

      n += nread;

      /* Algo 1 has no zlib header which requires us to give

       * inflate an extra dummy byte to read. To be on the safe

       * side we allow for up to 4 ff bytes.  */

      if( nread < count && zfx->algo == 1 && zfx->algo1hack < 4) {

    *(zfx->inbuf + n) = 0xFF;

    zfx->algo1hack++;

    n++;

                leave = 1;

      }

      zs->avail_in = n;

  }

  refill = 1;

  if( DBG_FILTER )

      log_debug("enter inflate: avail_in=%u, avail_out=%u\n",

        (unsigned)zs->avail_in, (unsigned)zs->avail_out);

  zrc = inflate ( zs, Z_SYNC_FLUSH );

  if( DBG_FILTER )

      log_debug("leave inflate: avail_in=%u, avail_out=%u, zrc=%d\n",

       (unsigned)zs->avail_in, (unsigned)zs->avail_out, zrc);

  if( zrc == Z_STREAM_END )

      rc = -1; /* eof */

  else if( zrc != Z_OK && zrc != Z_BUF_ERROR ) {

      if( zs->msg )

    log_error ("zlib inflate problem: %s\n", zs->msg );

      else

    log_error ("zlib inflate problem: rc=%d\n", zrc );

            write_status_error ("zlib.inflate", gpg_error (GPG_ERR_BAD_DATA));

            g10_exit (2);

  }

    } while (zs->avail_out && zrc != Z_STREAM_END && zrc != Z_BUF_ERROR

             && !leave);

    *ret_len = zfx->outbufsize - zs->avail_out;

    if( DBG_FILTER )

  log_debug("do_uncompress: returning %u bytes (%u ignored)\n",

                  (unsigned int)*ret_len, (unsigned int)zs->avail_in );

    return rc;

}

static int

compress_filter( void *opaque, int control,

     IOBUF a, byte *buf, size_t *ret_len)

{

    size_t size = *ret_len;

    compress_filter_context_t *zfx = opaque;

    z_stream *zs = zfx->opaque;

    int rc=0;

    if( control == IOBUFCTRL_UNDERFLOW ) {

  if( !zfx->status ) {

      zs = zfx->opaque = xmalloc_clear( sizeof *zs );

      init_uncompress( zfx, zs );

      zfx->status = 1;

  }

  zs->next_out = BYTEF_CAST (buf);

  zs->avail_out = size;

  zfx->outbufsize = size; /* needed only for calculation */

  rc = do_uncompress( zfx, zs, a, ret_len );

    }

    else if( control == IOBUFCTRL_FLUSH ) {

  if( !zfx->status ) {

      PACKET pkt;

      PKT_compressed cd;

      if(zfx->algo != COMPRESS_ALGO_ZIP

         && zfx->algo != COMPRESS_ALGO_ZLIB)

        BUG();

      memset( &cd, 0, sizeof cd );

      cd.len = 0;

      cd.algorithm = zfx->algo;

            /* Fixme: We should force a new CTB here:

               cd.new_ctb = zfx->new_ctb;

            */

      init_packet( &pkt );

      pkt.pkttype = PKT_COMPRESSED;

      pkt.pkt.compressed = &cd;

      if( build_packet( a, &pkt ))

    log_bug("build_packet(PKT_COMPRESSED) failed\n");

      zs = zfx->opaque = xmalloc_clear( sizeof *zs );

      init_compress( zfx, zs );

      zfx->status = 2;

  }

  zs->next_in = BYTEF_CAST (buf);

  zs->avail_in = size;

  rc = do_compress( zfx, zs, Z_NO_FLUSH, a );

    }

    else if( control == IOBUFCTRL_FREE ) {

  if( zfx->status == 1 ) {

      inflateEnd(zs);

      xfree(zs);

      zfx->opaque = NULL;

      xfree(zfx->outbuf); zfx->outbuf = NULL;

  }

  else if( zfx->status == 2 ) {

      zs->next_in = BYTEF_CAST (buf);

      zs->avail_in = 0;

      do_compress( zfx, zs, Z_FINISH, a );

      deflateEnd(zs);

      xfree(zs);

      zfx->opaque = NULL;

      xfree(zfx->outbuf); zfx->outbuf = NULL;

  }

        if (zfx->release)

          zfx->release (zfx);

    }

    else if( control == IOBUFCTRL_DESC )

        mem2str (buf, "compress_filter", *ret_len);

    return rc;

}

#endif /*HAVE_ZIP*/

static void

release_context (compress_filter_context_t *ctx)

{

  xfree(ctx->inbuf);

  ctx->inbuf = NULL;

  xfree(ctx->outbuf);

  ctx->outbuf = NULL;

  xfree (ctx);

}

/****************

 * Handle a compressed packet

 */

int

handle_compressed (ctrl_t ctrl, void *procctx, PKT_compressed *cd,

       int (*callback)(IOBUF, void *), void *passthru )

{

    int rc;

    if(check_compress_algo(cd->algorithm))

      return GPG_ERR_COMPR_ALGO;

    if(cd->algorithm) {

        compress_filter_context_t *cfx;

        cfx = xmalloc_clear (sizeof *cfx);

        cfx->release = release_context;

        cfx->algo = cd->algorithm;

        if (push_compress_filter(cd->buf, cfx, cd->algorithm))

          xfree (cfx);

    }

    if( callback )

  rc = callback(cd->buf, passthru );

    else

      rc = proc_packets (ctrl,procctx, cd->buf);

    cd->buf = NULL;

    return rc;

}

gpg_error_t

push_compress_filter(IOBUF out,compress_filter_context_t *zfx,int algo)

{

  return push_compress_filter2(out,zfx,algo,0);

}

/* Push a compress filter and return 0 if that succeeded.  */

gpg_error_t

push_compress_filter2(IOBUF out,compress_filter_context_t *zfx,

          int algo,int rel)

{

  gpg_error_t err = gpg_error (GPG_ERR_FALSE);

  if(algo>=0)

    zfx->algo=algo;

  else

    zfx->algo=DEFAULT_COMPRESS_ALGO;

  switch(zfx->algo)

    {

    case COMPRESS_ALGO_NONE:

      break;

#ifdef HAVE_ZIP

    case COMPRESS_ALGO_ZIP:

    case COMPRESS_ALGO_ZLIB:

      iobuf_push_filter2(out,compress_filter,zfx,rel);

      err = 0;

      break;

#endif

#ifdef HAVE_BZIP2

    case COMPRESS_ALGO_BZIP2:

      iobuf_push_filter2(out,compress_filter_bz2,zfx,rel);

      err = 0;

      break;

#endif

    default:

      BUG();

    }

  return err;

}