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git/archive-zip.c
Junio C Hamano ef49a7a012 zlib: zlib can only process 4GB at a time 
The size of objects we read from the repository and data we try to put
into the repository are represented in "unsigned long", so that on larger
architectures we can handle objects that weigh more than 4GB.

But the interface defined in zlib.h to communicate with inflate/deflate
limits avail_in (how many bytes of input are we calling zlib with) and
avail_out (how many bytes of output from zlib are we ready to accept)
fields effectively to 4GB by defining their type to be uInt.

In many places in our code, we allocate a large buffer (e.g. mmap'ing a
large loose object file) and tell zlib its size by assigning the size to
avail_in field of the stream, but that will truncate the high octets of
the real size. The worst part of this story is that we often pass around
z_stream (the state object used by zlib) to keep track of the number of
used bytes in input/output buffer by inspecting these two fields, which
practically limits our callchain to the same 4GB limit.

Wrap z_stream in another structure git_zstream that can express avail_in
and avail_out in unsigned long. For now, just die() when the caller gives
a size that cannot be given to a single zlib call. In later patches in the
series, we would make git_inflate() and git_deflate() internally loop to
give callers an illusion that our "improved" version of zlib interface can
operate on a buffer larger than 4GB in one go.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-06-10 11:52:15 -07:00

281 lines
7.3 KiB
C
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/*
* Copyright (c) 2006 Rene Scharfe
*/
#include "cache.h"
#include "archive.h"
static int zip_date;
static int zip_time;
static unsigned char *zip_dir;
static unsigned int zip_dir_size;
static unsigned int zip_offset;
static unsigned int zip_dir_offset;
static unsigned int zip_dir_entries;
#define ZIP_DIRECTORY_MIN_SIZE (1024 * 1024)
struct zip_local_header {
unsigned char magic[4];
unsigned char version[2];
unsigned char flags[2];
unsigned char compression_method[2];
unsigned char mtime[2];
unsigned char mdate[2];
unsigned char crc32[4];
unsigned char compressed_size[4];
unsigned char size[4];
unsigned char filename_length[2];
unsigned char extra_length[2];
unsigned char _end[1];
};
struct zip_dir_header {
unsigned char magic[4];
unsigned char creator_version[2];
unsigned char version[2];
unsigned char flags[2];
unsigned char compression_method[2];
unsigned char mtime[2];
unsigned char mdate[2];
unsigned char crc32[4];
unsigned char compressed_size[4];
unsigned char size[4];
unsigned char filename_length[2];
unsigned char extra_length[2];
unsigned char comment_length[2];
unsigned char disk[2];
unsigned char attr1[2];
unsigned char attr2[4];
unsigned char offset[4];
unsigned char _end[1];
};
struct zip_dir_trailer {
unsigned char magic[4];
unsigned char disk[2];
unsigned char directory_start_disk[2];
unsigned char entries_on_this_disk[2];
unsigned char entries[2];
unsigned char size[4];
unsigned char offset[4];
unsigned char comment_length[2];
unsigned char _end[1];
};
/*
* On ARM, padding is added at the end of the struct, so a simple
* sizeof(struct ...) reports two bytes more than the payload size
* we're interested in.
*/
#define ZIP_LOCAL_HEADER_SIZE offsetof(struct zip_local_header, _end)
#define ZIP_DIR_HEADER_SIZE offsetof(struct zip_dir_header, _end)
#define ZIP_DIR_TRAILER_SIZE offsetof(struct zip_dir_trailer, _end)
static void copy_le16(unsigned char *dest, unsigned int n)
{
dest[0] = 0xff & n;
dest[1] = 0xff & (n >> 010);
}
static void copy_le32(unsigned char *dest, unsigned int n)
{
dest[0] = 0xff & n;
dest[1] = 0xff & (n >> 010);
dest[2] = 0xff & (n >> 020);
dest[3] = 0xff & (n >> 030);
}
static void *zlib_deflate(void *data, unsigned long size,
int compression_level, unsigned long *compressed_size)
{
git_zstream stream;
unsigned long maxsize;
void *buffer;
int result;
memset(&stream, 0, sizeof(stream));
git_deflate_init(&stream, compression_level);
maxsize = git_deflate_bound(&stream, size);
buffer = xmalloc(maxsize);
stream.next_in = data;
stream.avail_in = size;
stream.next_out = buffer;
stream.avail_out = maxsize;
do {
result = git_deflate(&stream, Z_FINISH);
} while (result == Z_OK);
if (result != Z_STREAM_END) {
free(buffer);
return NULL;
}
git_deflate_end(&stream);
*compressed_size = stream.total_out;
return buffer;
}
static int write_zip_entry(struct archiver_args *args,
const unsigned char *sha1, const char *path, size_t pathlen,
unsigned int mode, void *buffer, unsigned long size)
{
struct zip_local_header header;
struct zip_dir_header dirent;
unsigned long attr2;
unsigned long compressed_size;
unsigned long uncompressed_size;
unsigned long crc;
unsigned long direntsize;
int method;
unsigned char *out;
void *deflated = NULL;
crc = crc32(0, NULL, 0);
if (pathlen > 0xffff) {
return error("path too long (%d chars, SHA1: %s): %s",
(int)pathlen, sha1_to_hex(sha1), path);
}
if (S_ISDIR(mode) || S_ISGITLINK(mode)) {
method = 0;
attr2 = 16;
out = NULL;
uncompressed_size = 0;
compressed_size = 0;
} else if (S_ISREG(mode) || S_ISLNK(mode)) {
method = 0;
attr2 = S_ISLNK(mode) ? ((mode | 0777) << 16) :
(mode & 0111) ? ((mode) << 16) : 0;
if (S_ISREG(mode) && args->compression_level != 0)
method = 8;
crc = crc32(crc, buffer, size);
out = buffer;
uncompressed_size = size;
compressed_size = size;
} else {
return error("unsupported file mode: 0%o (SHA1: %s)", mode,
sha1_to_hex(sha1));
}
if (method == 8) {
deflated = zlib_deflate(buffer, size, args->compression_level,
&compressed_size);
if (deflated && compressed_size - 6 < size) {
/* ZLIB --> raw compressed data (see RFC 1950) */
/* CMF and FLG ... */
out = (unsigned char *)deflated + 2;
compressed_size -= 6; /* ... and ADLER32 */
} else {
method = 0;
compressed_size = size;
}
}
/* make sure we have enough free space in the dictionary */
direntsize = ZIP_DIR_HEADER_SIZE + pathlen;
while (zip_dir_size < zip_dir_offset + direntsize) {
zip_dir_size += ZIP_DIRECTORY_MIN_SIZE;
zip_dir = xrealloc(zip_dir, zip_dir_size);
}
copy_le32(dirent.magic, 0x02014b50);
copy_le16(dirent.creator_version,
S_ISLNK(mode) || (S_ISREG(mode) && (mode & 0111)) ? 0x0317 : 0);
copy_le16(dirent.version, 10);
copy_le16(dirent.flags, 0);
copy_le16(dirent.compression_method, method);
copy_le16(dirent.mtime, zip_time);
copy_le16(dirent.mdate, zip_date);
copy_le32(dirent.crc32, crc);
copy_le32(dirent.compressed_size, compressed_size);
copy_le32(dirent.size, uncompressed_size);
copy_le16(dirent.filename_length, pathlen);
copy_le16(dirent.extra_length, 0);
copy_le16(dirent.comment_length, 0);
copy_le16(dirent.disk, 0);
copy_le16(dirent.attr1, 0);
copy_le32(dirent.attr2, attr2);
copy_le32(dirent.offset, zip_offset);
memcpy(zip_dir + zip_dir_offset, &dirent, ZIP_DIR_HEADER_SIZE);
zip_dir_offset += ZIP_DIR_HEADER_SIZE;
memcpy(zip_dir + zip_dir_offset, path, pathlen);
zip_dir_offset += pathlen;
zip_dir_entries++;
copy_le32(header.magic, 0x04034b50);
copy_le16(header.version, 10);
copy_le16(header.flags, 0);
copy_le16(header.compression_method, method);
copy_le16(header.mtime, zip_time);
copy_le16(header.mdate, zip_date);
copy_le32(header.crc32, crc);
copy_le32(header.compressed_size, compressed_size);
copy_le32(header.size, uncompressed_size);
copy_le16(header.filename_length, pathlen);
copy_le16(header.extra_length, 0);
write_or_die(1, &header, ZIP_LOCAL_HEADER_SIZE);
zip_offset += ZIP_LOCAL_HEADER_SIZE;
write_or_die(1, path, pathlen);
zip_offset += pathlen;
if (compressed_size > 0) {
write_or_die(1, out, compressed_size);
zip_offset += compressed_size;
}
free(deflated);
return 0;
}
static void write_zip_trailer(const unsigned char *sha1)
{
struct zip_dir_trailer trailer;
copy_le32(trailer.magic, 0x06054b50);
copy_le16(trailer.disk, 0);
copy_le16(trailer.directory_start_disk, 0);
copy_le16(trailer.entries_on_this_disk, zip_dir_entries);
copy_le16(trailer.entries, zip_dir_entries);
copy_le32(trailer.size, zip_dir_offset);
copy_le32(trailer.offset, zip_offset);
copy_le16(trailer.comment_length, sha1 ? 40 : 0);
write_or_die(1, zip_dir, zip_dir_offset);
write_or_die(1, &trailer, ZIP_DIR_TRAILER_SIZE);
if (sha1)
write_or_die(1, sha1_to_hex(sha1), 40);
}
static void dos_time(time_t *time, int *dos_date, int *dos_time)
{
struct tm *t = localtime(time);
*dos_date = t->tm_mday + (t->tm_mon + 1) * 32 +
(t->tm_year + 1900 - 1980) * 512;
*dos_time = t->tm_sec / 2 + t->tm_min * 32 + t->tm_hour * 2048;
}
int write_zip_archive(struct archiver_args *args)
{
int err;
dos_time(&args->time, &zip_date, &zip_time);
zip_dir = xmalloc(ZIP_DIRECTORY_MIN_SIZE);
zip_dir_size = ZIP_DIRECTORY_MIN_SIZE;
err = write_archive_entries(args, write_zip_entry);
if (!err)
write_zip_trailer(args->commit_sha1);
free(zip_dir);
return err;
}
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