void PackUnix::pack4(OutputFile *fo, Filter &)
{
writePackHeader(fo);
unsigned tmp;
set_te32(&tmp, overlay_offset);
fo->write(&tmp, sizeof(tmp));
}
void PackUnix::pack(OutputFile *fo)
{
Filter ft(ph.level);
ft.addvalue = 0;
b_len = 0;
progid = 0;
// set options
blocksize = opt->o_unix.blocksize;
if (blocksize <= 0)
blocksize = BLOCKSIZE;
if ((off_t)blocksize > file_size)
blocksize = file_size;
// init compression buffers
ibuf.alloc(blocksize);
obuf.allocForCompression(blocksize);
fi->seek(0, SEEK_SET);
pack1(fo, ft); // generate Elf header, etc.
p_info hbuf;
set_te32(&hbuf.p_progid, progid);
set_te32(&hbuf.p_filesize, file_size);
set_te32(&hbuf.p_blocksize, blocksize);
fo->write(&hbuf, sizeof(hbuf));
// append the compressed body
if (pack2(fo, ft)) {
// write block end marker (uncompressed size 0)
b_info hdr; memset(&hdr, 0, sizeof(hdr));
set_le32(&hdr.sz_cpr, UPX_MAGIC_LE32);
fo->write(&hdr, sizeof(hdr));
}
pack3(fo, ft); // append loader
pack4(fo, ft); // append PackHeader and overlay_offset; update Elf header
// finally check the compression ratio
if (!checkFinalCompressionRatio(fo))
throwNotCompressible();
}
void
PackUnix::patchLoaderChecksum()
{
unsigned char *const ptr = getLoader();
l_info *const lp = &linfo;
// checksum for loader; also some PackHeader info
lp->l_magic = UPX_MAGIC_LE32; // LE32 always
set_te16(&lp->l_lsize, (upx_uint16_t) lsize);
lp->l_version = (unsigned char) ph.version;
lp->l_format = (unsigned char) ph.format;
// INFO: lp->l_checksum is currently unused
set_te32(&lp->l_checksum, upx_adler32(ptr, lsize));
}
void PackUnix::packExtent(
const Extent &x,
unsigned &total_in,
unsigned &total_out,
Filter *ft,
OutputFile *fo,
unsigned hdr_u_len
)
{
unsigned const init_u_adler = ph.u_adler;
unsigned const init_c_adler = ph.c_adler;
MemBuffer hdr_ibuf;
if (hdr_u_len) {
hdr_ibuf.alloc(hdr_u_len);
fi->seek(0, SEEK_SET);
int l = fi->readx(hdr_ibuf, hdr_u_len);
(void)l;
}
fi->seek(x.offset, SEEK_SET);
for (off_t rest = x.size; 0 != rest; ) {
int const filter_strategy = ft ? getStrategy(*ft) : 0;
int l = fi->readx(ibuf, UPX_MIN(rest, (off_t)blocksize));
if (l == 0) {
break;
}
rest -= l;
// Note: compression for a block can fail if the
// file is e.g. blocksize + 1 bytes long
// compress
ph.c_len = ph.u_len = l;
ph.overlap_overhead = 0;
unsigned end_u_adler = 0;
if (ft) {
// compressWithFilters() updates u_adler _inside_ compress();
// that is, AFTER filtering. We want BEFORE filtering,
// so that decompression checks the end-to-end checksum.
end_u_adler = upx_adler32(ibuf, ph.u_len, ph.u_adler);
ft->buf_len = l;
// compressWithFilters() requirements?
ph.filter = 0;
ph.filter_cto = 0;
ft->id = 0;
ft->cto = 0;
compressWithFilters(ft, OVERHEAD, NULL_cconf, filter_strategy,
0, 0, 0, hdr_ibuf, hdr_u_len);
}
else {
(void) compress(ibuf, ph.u_len, obuf); // ignore return value
}
if (ph.c_len < ph.u_len) {
const upx_bytep tbuf = NULL;
if (ft == NULL || ft->id == 0) tbuf = ibuf;
ph.overlap_overhead = OVERHEAD;
if (!testOverlappingDecompression(obuf, tbuf, ph.overlap_overhead)) {
// not in-place compressible
ph.c_len = ph.u_len;
}
}
if (ph.c_len >= ph.u_len) {
// block is not compressible
ph.c_len = ph.u_len;
memcpy(obuf, ibuf, ph.c_len);
// must update checksum of compressed data
ph.c_adler = upx_adler32(ibuf, ph.u_len, ph.saved_c_adler);
}
// write block sizes
b_info tmp;
if (hdr_u_len) {
unsigned hdr_c_len = 0;
MemBuffer hdr_obuf;
hdr_obuf.allocForCompression(hdr_u_len);
int r = upx_compress(hdr_ibuf, hdr_u_len, hdr_obuf, &hdr_c_len, 0,
ph.method, 10, NULL, NULL);
if (r != UPX_E_OK)
throwInternalError("header compression failed");
if (hdr_c_len >= hdr_u_len)
throwInternalError("header compression size increase");
ph.saved_u_adler = upx_adler32(hdr_ibuf, hdr_u_len, init_u_adler);
ph.saved_c_adler = upx_adler32(hdr_obuf, hdr_c_len, init_c_adler);
ph.u_adler = upx_adler32(ibuf, ph.u_len, ph.saved_u_adler);
ph.c_adler = upx_adler32(obuf, ph.c_len, ph.saved_c_adler);
end_u_adler = ph.u_adler;
memset(&tmp, 0, sizeof(tmp));
set_te32(&tmp.sz_unc, hdr_u_len);
set_te32(&tmp.sz_cpr, hdr_c_len);
tmp.b_method = (unsigned char) ph.method;
fo->write(&tmp, sizeof(tmp));
b_len += sizeof(b_info);
fo->write(hdr_obuf, hdr_c_len);
total_out += hdr_c_len;
total_in += hdr_u_len;
hdr_u_len = 0; // compress hdr one time only
}
memset(&tmp, 0, sizeof(tmp));
set_te32(&tmp.sz_unc, ph.u_len);
set_te32(&tmp.sz_cpr, ph.c_len);
if (ph.c_len < ph.u_len) {
tmp.b_method = (unsigned char) ph.method;
if (ft) {
tmp.b_ftid = (unsigned char) ft->id;
tmp.b_cto8 = ft->cto;
}
}
fo->write(&tmp, sizeof(tmp));
b_len += sizeof(b_info);
if (ft) {
ph.u_adler = end_u_adler;
}
// write compressed data
if (ph.c_len < ph.u_len) {
fo->write(obuf, ph.c_len);
// Checks ph.u_adler after decompression, after unfiltering
verifyOverlappingDecompression(ft);
}
else {
fo->write(ibuf, ph.u_len);
}
total_in += ph.u_len;
total_out += ph.c_len;
}
}
int PackUnix::pack2(OutputFile *fo, Filter &ft)
{
// compress blocks
unsigned total_in = 0;
unsigned total_out = 0;
// FIXME: ui_total_passes is not correct with multiple blocks...
// ui_total_passes = (file_size + blocksize - 1) / blocksize;
// if (ui_total_passes == 1)
// ui_total_passes = 0;
unsigned remaining = file_size;
unsigned n_block = 0;
while (remaining > 0)
{
// FIXME: disable filters if we have more than one block.
// FIXME: There is only 1 un-filter in the stub [as of 2002-11-10].
// So the next block really has no choice!
// This merely prevents an assert() in compressWithFilters(),
// which assumes it has free choice on each call [block].
// And if the choices aren't the same on each block,
// then un-filtering will give incorrect results.
int filter_strategy = getStrategy(ft);
if (file_size > (off_t)blocksize)
filter_strategy = -3; // no filters
int l = fi->readx(ibuf, UPX_MIN(blocksize, remaining));
remaining -= l;
// Note: compression for a block can fail if the
// file is e.g. blocksize + 1 bytes long
// compress
ph.overlap_overhead = 0;
ph.c_len = ph.u_len = l;
ft.buf_len = l;
// compressWithFilters() updates u_adler _inside_ compress();
// that is, AFTER filtering. We want BEFORE filtering,
// so that decompression checks the end-to-end checksum.
unsigned const end_u_adler = upx_adler32(ibuf, ph.u_len, ph.u_adler);
compressWithFilters(&ft, OVERHEAD, NULL_cconf, filter_strategy,
!!n_block++); // check compression ratio only on first block
if (ph.c_len < ph.u_len) {
const upx_bytep tbuf = NULL;
if (ft.id == 0) tbuf = ibuf;
ph.overlap_overhead = OVERHEAD;
if (!testOverlappingDecompression(obuf, tbuf, ph.overlap_overhead)) {
// not in-place compressible
ph.c_len = ph.u_len;
}
}
if (ph.c_len >= ph.u_len) {
// block is not compressible
ph.c_len = ph.u_len;
// must manually update checksum of compressed data
ph.c_adler = upx_adler32(ibuf, ph.u_len, ph.saved_c_adler);
}
// write block header
b_info blk_info;
memset(&blk_info, 0, sizeof(blk_info));
set_te32(&blk_info.sz_unc, ph.u_len);
set_te32(&blk_info.sz_cpr, ph.c_len);
if (ph.c_len < ph.u_len) {
blk_info.b_method = (unsigned char) ph.method;
blk_info.b_ftid = (unsigned char) ph.filter;
blk_info.b_cto8 = (unsigned char) ph.filter_cto;
}
fo->write(&blk_info, sizeof(blk_info));
b_len += sizeof(b_info);
// write compressed data
if (ph.c_len < ph.u_len) {
fo->write(obuf, ph.c_len);
verifyOverlappingDecompression(); // uses ph.u_adler
}
else {
fo->write(ibuf, ph.u_len);
}
ph.u_adler = end_u_adler;
total_in += ph.u_len;
total_out += ph.c_len;
}
// update header with totals
ph.u_len = total_in;
ph.c_len = total_out;
if ((off_t)total_in != file_size) {
throwEOFException();
}
return 1; // default: write end-of-compression bhdr next
}
int PackVmlinuzARMEL::decompressKernel()
{
// read whole kernel image
obuf.alloc(file_size);
fi->seek(0, SEEK_SET);
fi->readx(obuf, file_size);
//checkAlreadyPacked(obuf + setup_size, UPX_MIN(file_size - setup_size, (off_t)1024));
// Find head.S:
// bl decompress_kernel # 0xeb......
// b call_kernel # 0xea......
//LC0: .word LC0 # self!
unsigned decompress_kernel = 0;
unsigned caller1 = 0;
unsigned caller2 = 0;
unsigned got_start = 0;
unsigned got_end = 0;
for (unsigned j = 0; j < 0x400; j+=4) {
unsigned w;
if (j!=get_te32(j + obuf)) {
continue;
}
if (0xea000000!=(0xff000000& get_te32(j - 4 + obuf))
|| 0xeb000000!=(0xff000000&(w= get_te32(j - 8 + obuf))) ) {
continue;
}
caller1 = j - 8;
decompress_kernel = ((0x00ffffff & w)<<2) + 8+ caller1;
for (unsigned k = 12; k<=128; k+=4) {
w = get_te32(j - k + obuf);
if (0xeb000000==(0xff000000 & w)
&& decompress_kernel==(((0x00ffffff & w)<<2) + 8+ j - k) ) {
caller2 = j - k;
break;
}
}
got_start = get_te32(5*4 + j + obuf);
got_end = get_te32(6*4 + j + obuf);
#if 0 /*{*/
printf("decompress_kernel=0x%x got_start=0x%x got_end=0x%x\n",
decompress_kernel, got_start, got_end);
#endif /*}*/
break;
}
if (0==decompress_kernel) {
return 0;
}
// Find first subroutine that is called by decompress_kernel,
// which we will consider to be the start of the gunzip module
// and the end of the non-gunzip modules.
for (unsigned j = decompress_kernel; j < (unsigned)file_size; j+=4) {
unsigned w = get_te32(j + obuf);
if (0xeb800000==(0xff800000 & w)) {
setup_size = 8+ ((0xff000000 | w)<<2) + j;
// Move the GlobalOffsetTable.
for (unsigned k = got_start; k < got_end; k+=4) {
w = get_te32(k + obuf);
// FIXME: must relocate w
set_te32(k - got_start + setup_size + obuf, w);
}
setup_size += got_end - got_start;
set_te32(&obuf[caller1], 0xeb000000 |
(0x00ffffff & ((setup_size - (8+ caller1))>>2)) );
set_te32(&obuf[caller2], 0xeb000000 |
(0x00ffffff & ((setup_size - (8+ caller2))>>2)) );
break;
}
}
