/*-
* Copyright 2003-2005 Colin Percival
* All rights reserved
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted providing 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 ``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 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.
*/
#if 0
__FBSDID("$FreeBSD: src/usr.bin/bsdiff/bspatch/bspatch.c,v 1.1 2005/08/06 01:59:06 cperciva Exp $");
#endif
#include "bspatch.h"
#include <bzlib.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <inttypes.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <algorithm>
#include <memory>
#include <limits>
#include <vector>
#include "extents.h"
#include "extents_file.h"
#include "file.h"
#include "file_interface.h"
#include "memory_file.h"
namespace {
int64_t ParseInt64(u_char* buf) {
int64_t y;
y = buf[7] & 0x7F;
y = y * 256;
y += buf[6];
y = y * 256;
y += buf[5];
y = y * 256;
y += buf[4];
y = y * 256;
y += buf[3];
y = y * 256;
y += buf[2];
y = y * 256;
y += buf[1];
y = y * 256;
y += buf[0];
if (buf[7] & 0x80)
y = -y;
return y;
}
bool ReadBZ2(BZFILE* pfbz2, uint8_t* data, size_t size) {
int bz2err;
size_t lenread = BZ2_bzRead(&bz2err, pfbz2, data, size);
if (lenread < size || (bz2err != BZ_OK && bz2err != BZ_STREAM_END))
return false;
return true;
}
bool ReadBZ2AndWriteAll(const std::unique_ptr<bsdiff::FileInterface>& file,
BZFILE* pfbz2,
size_t size,
uint8_t* buf,
size_t buf_size) {
while (size > 0) {
size_t bytes_to_read = std::min(size, buf_size);
if (!ReadBZ2(pfbz2, buf, bytes_to_read))
return false;
if (!WriteAll(file, buf, bytes_to_read))
return false;
size -= bytes_to_read;
}
return true;
}
} // namespace
namespace bsdiff {
bool WriteAll(const std::unique_ptr<FileInterface>& file,
const uint8_t* data,
size_t size) {
size_t offset = 0, written;
while (offset < size) {
if (!file->Write(data + offset, size - offset, &written) || written == 0)
return false;
offset += written;
}
return true;
}
bool IsOverlapping(const char* old_filename,
const char* new_filename,
const std::vector<ex_t>& old_extents,
const std::vector<ex_t>& new_extents) {
struct stat old_stat, new_stat;
if (stat(new_filename, &new_stat) == -1) {
if (errno == ENOENT)
return false;
err(1, "Error stat the new filename %s", new_filename);
}
if (stat(old_filename, &old_stat) == -1)
err(1, "Error stat the old filename %s", old_filename);
if (old_stat.st_dev != new_stat.st_dev || old_stat.st_ino != new_stat.st_ino)
return false;
if (old_extents.empty() && new_extents.empty())
return true;
for (ex_t old_ex : old_extents)
for (ex_t new_ex : new_extents)
if (static_cast<uint64_t>(old_ex.off) < new_ex.off + new_ex.len &&
static_cast<uint64_t>(new_ex.off) < old_ex.off + old_ex.len)
return true;
return false;
}
int bspatch(
const char* old_filename, const char* new_filename,
const char* patch_filename,
const char* old_extents, const char* new_extents) {
FILE* f, *cpf, *dpf, *epf;
BZFILE* cpfbz2, *dpfbz2, *epfbz2;
int bz2err;
ssize_t bzctrllen, bzdatalen;
u_char header[32], buf[8];
off_t ctrl[3];
int using_extents = (old_extents != NULL || new_extents != NULL);
// Open patch file.
if ((f = fopen(patch_filename, "r")) == NULL)
err(1, "fopen(%s)", patch_filename);
// File format:
// 0 8 "BSDIFF40"
// 8 8 X
// 16 8 Y
// 24 8 sizeof(new_filename)
// 32 X bzip2(control block)
// 32+X Y bzip2(diff block)
// 32+X+Y ??? bzip2(extra block)
// with control block a set of triples (x,y,z) meaning "add x bytes
// from oldfile to x bytes from the diff block; copy y bytes from the
// extra block; seek forwards in oldfile by z bytes".
// Read header.
if (fread(header, 1, 32, f) < 32) {
if (feof(f))
errx(1, "Corrupt patch\n");
err(1, "fread(%s)", patch_filename);
}
// Check for appropriate magic.
if (memcmp(header, "BSDIFF40", 8) != 0)
errx(1, "Corrupt patch\n");
// Read lengths from header.
uint64_t oldsize, newsize;
bzctrllen = ParseInt64(header + 8);
bzdatalen = ParseInt64(header + 16);
int64_t signed_newsize = ParseInt64(header + 24);
newsize = signed_newsize;
if ((bzctrllen < 0) || (bzdatalen < 0) || (signed_newsize < 0))
errx(1, "Corrupt patch\n");
// Close patch file and re-open it via libbzip2 at the right places.
if (fclose(f))
err(1, "fclose(%s)", patch_filename);
if ((cpf = fopen(patch_filename, "r")) == NULL)
err(1, "fopen(%s)", patch_filename);
if (fseek(cpf, 32, SEEK_SET))
err(1, "fseeko(%s, %lld)", patch_filename, (long long)32);
if ((cpfbz2 = BZ2_bzReadOpen(&bz2err, cpf, 0, 0, NULL, 0)) == NULL)
errx(1, "BZ2_bzReadOpen, bz2err = %d", bz2err);
if ((dpf = fopen(patch_filename, "r")) == NULL)
err(1, "fopen(%s)", patch_filename);
if (fseek(dpf, 32 + bzctrllen, SEEK_SET))
err(1, "fseeko(%s, %lld)", patch_filename, (long long)(32 + bzctrllen));
if ((dpfbz2 = BZ2_bzReadOpen(&bz2err, dpf, 0, 0, NULL, 0)) == NULL)
errx(1, "BZ2_bzReadOpen, bz2err = %d", bz2err);
if ((epf = fopen(patch_filename, "r")) == NULL)
err(1, "fopen(%s)", patch_filename);
if (fseek(epf, 32 + bzctrllen + bzdatalen, SEEK_SET))
err(1, "fseeko(%s, %lld)", patch_filename,
(long long)(32 + bzctrllen + bzdatalen));
if ((epfbz2 = BZ2_bzReadOpen(&bz2err, epf, 0, 0, NULL, 0)) == NULL)
errx(1, "BZ2_bzReadOpen, bz2err = %d", bz2err);
// Open input file for reading.
std::unique_ptr<FileInterface> old_file = File::FOpen(old_filename, O_RDONLY);
if (!old_file)
err(1, "Error opening the old filename");
std::vector<ex_t> parsed_old_extents;
if (using_extents) {
if (!ParseExtentStr(old_extents, &parsed_old_extents))
errx(1, "Error parsing the old extents");
old_file.reset(new ExtentsFile(std::move(old_file), parsed_old_extents));
}
if (!old_file->GetSize(&oldsize))
err(1, "cannot obtain the size of %s", old_filename);
uint64_t old_file_pos = 0;
// Open output file for writing.
std::unique_ptr<FileInterface> new_file =
File::FOpen(new_filename, O_CREAT | O_WRONLY);
if (!new_file)
err(1, "Error opening the new filename %s", new_filename);
std::vector<ex_t> parsed_new_extents;
if (using_extents) {
if (!ParseExtentStr(new_extents, &parsed_new_extents))
errx(1, "Error parsing the new extents");
new_file.reset(new ExtentsFile(std::move(new_file), parsed_new_extents));
}
if (IsOverlapping(old_filename, new_filename, parsed_old_extents,
parsed_new_extents)) {
// New and old file is overlapping, we can not stream output to new file,
// cache it in the memory and write to the file at the end.
new_file.reset(new MemoryFile(std::move(new_file), newsize));
}
// The oldpos can be negative, but the new pos is only incremented linearly.
int64_t oldpos = 0;
uint64_t newpos = 0;
std::vector<uint8_t> old_buf(1024 * 1024), new_buf(1024 * 1024);
while (newpos < newsize) {
int64_t i;
// Read control data.
for (i = 0; i <= 2; i++) {
if (!ReadBZ2(cpfbz2, buf, 8))
errx(1, "Corrupt patch\n");
ctrl[i] = ParseInt64(buf);
}
// Sanity-check.
if (ctrl[0] < 0 || ctrl[1] < 0)
errx(1, "Corrupt patch\n");
// Sanity-check.
if (newpos + ctrl[0] > newsize)
errx(1, "Corrupt patch\n");
// Add old data to diff string. It is enough to fseek once, at
// the beginning of the sequence, to avoid unnecessary overhead.
if ((i = oldpos) < 0) {
// Write diff block directly to new file without adding old data,
// because we will skip part where |oldpos| < 0.
if (!ReadBZ2AndWriteAll(new_file, dpfbz2, -i, new_buf.data(),
new_buf.size()))
errx(1, "Error during ReadBZ2AndWriteAll()");
i = 0;
}
// We just checked that |i| is not negative.
if (static_cast<uint64_t>(i) != old_file_pos && !old_file->Seek(i))
err(1, "error seeking input file to offset %" PRId64, i);
if ((old_file_pos = oldpos + ctrl[0]) > oldsize)
old_file_pos = oldsize;
size_t chunk_size = old_file_pos - i;
while (chunk_size > 0) {
size_t read_bytes;
size_t bytes_to_read = std::min(chunk_size, old_buf.size());
if (!old_file->Read(old_buf.data(), bytes_to_read, &read_bytes))
err(1, "error reading from input file");
if (!read_bytes)
errx(1, "EOF reached while reading from input file");
// Read same amount of bytes from diff block
if (!ReadBZ2(dpfbz2, new_buf.data(), read_bytes))
errx(1, "Corrupt patch\n");
// new_buf already has data from diff block, adds old data to it.
for (size_t k = 0; k < read_bytes; k++)
new_buf[k] += old_buf[k];
if (!WriteAll(new_file, new_buf.data(), read_bytes))
err(1, "Error writing new file.");
chunk_size -= read_bytes;
}
// Adjust pointers.
newpos += ctrl[0];
oldpos += ctrl[0];
if (oldpos > static_cast<int64_t>(oldsize)) {
// Write diff block directly to new file without adding old data,
// because we skipped part where |oldpos| > oldsize.
if (!ReadBZ2AndWriteAll(new_file, dpfbz2, oldpos - oldsize,
new_buf.data(), new_buf.size()))
errx(1, "Error during ReadBZ2AndWriteAll()");
}
// Sanity-check.
if (newpos + ctrl[1] > newsize)
errx(1, "Corrupt patch\n");
// Read extra block.
if (!ReadBZ2AndWriteAll(new_file, epfbz2, ctrl[1], new_buf.data(),
new_buf.size()))
errx(1, "Error during ReadBZ2AndWriteAll()");
// Adjust pointers.
newpos += ctrl[1];
oldpos += ctrl[2];
}
// Close input file.
old_file->Close();
// Clean up the bzip2 reads.
BZ2_bzReadClose(&bz2err, cpfbz2);
BZ2_bzReadClose(&bz2err, dpfbz2);
BZ2_bzReadClose(&bz2err, epfbz2);
if (fclose(cpf) || fclose(dpf) || fclose(epf))
err(1, "fclose(%s)", patch_filename);
if (!new_file->Close())
err(1, "Error closing new file %s", new_filename);
return 0;
}
} // namespace bsdiff