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rufus/src/bled/decompress_vtsi.c
2021-07-26 16:57:48 +01:00

190 lines
4.5 KiB
C

/******************************************************************************
* decompress_vtsi.c
*
* Copyright (c) 2021, longpanda <admin@ventoy.net>
*
* Licensed under GPLv2 or later, see file LICENSE in this source tree.
*
*/
#include "libbb.h"
#include "bb_archive.h"
/*
* Structure of a Ventoy Sparse Image (VTSI) file:
*
+---------------------------------
+ sector 0 ~ sector N-1
+ data area
+---------------------------------
+ sector N ~ sector M - 1
+ segment[0]
+ segment[1]
+ segment[2]
+ .....
+ (may be some align data (segment data aligned with 512) ...)
+---------------------------------
+ sector M
+ footer
+---------------------------------
*
* All the integers are in little endian
* The sector size is fixed 512 for ventoy image file.
*
*/
#define VTSI_MAGIC 0x0000594F544E4556ULL // "VENTOY\0\0"
#pragma pack(1)
typedef struct {
uint64_t disk_start_sector;
uint64_t sector_num;
uint64_t data_offset;
} VTSI_SEGMENT;
typedef struct {
uint64_t magic;
uint16_t version_major;
uint16_t version_minor;
uint64_t disk_size;
uint32_t disk_signature;
uint32_t foot_chksum;
uint32_t segment_num;
uint32_t segment_chksum;
uint64_t segment_offset;
uint8_t reserved[512 - 44];
} VTSI_FOOTER;
#pragma pack()
extern int __static_assert__[sizeof(VTSI_FOOTER) == 512 ? 1 : -1];
#define MAX_READ_BUF (8 * 1024 * 1024)
static int check_vtsi_footer(VTSI_FOOTER* footer)
{
int valid = 0;
uint32_t i, oldsum, calcsum;
if (footer->magic != VTSI_MAGIC)
bb_error_msg_and_err("invalid vtsi magic 0x%llX", footer->magic);
/* check footer checksum */
oldsum = footer->foot_chksum;
footer->foot_chksum = 0;
for (i = 0, calcsum = 0; i < sizeof(VTSI_FOOTER); i++)
calcsum += *((uint8_t*)footer + i);
calcsum = ~calcsum;
if (calcsum != oldsum)
bb_error_msg_and_err("invalid vtsi footer chksum 0x%X 0x%X", calcsum, oldsum);
/* check version (if the major doesn't match, we consider that a breaking change occurred) */
if (footer->version_major != 1)
bb_error_msg_and_err("unsupported vtsi version %d.%d", footer->version_major, footer->version_minor);
valid = 1;
err:
return valid;
}
static int check_vtsi_segment(VTSI_FOOTER* footer, VTSI_SEGMENT* segment)
{
int valid = 0;
uint32_t i, oldsum, calcsum;
/* check segment checksum */
oldsum = footer->segment_chksum;
for (i = 0, calcsum = 0; i < sizeof(VTSI_SEGMENT) * footer->segment_num; i++)
calcsum += *((uint8_t*)segment + i);
calcsum = ~calcsum;
if (calcsum != oldsum)
bb_error_msg_and_err("invalid vtsi segment chksum 0x%X 0x%X", calcsum, oldsum);
valid = 1;
err:
return valid;
}
IF_DESKTOP(long long) int FAST_FUNC unpack_vtsi_stream(transformer_state_t* xstate)
{
IF_DESKTOP(long long) int n = -EFAULT;
long long tot = 0;
off_t src_size;
int src_fd = 0;
size_t wsize = 0;
ssize_t retval = 0;
uint64_t seg = 0;
int64_t datalen = 0;
uint64_t phy_offset = 0;
size_t max_buflen = MAX_READ_BUF;
uint8_t* buf = NULL;
VTSI_SEGMENT* segment = NULL;
VTSI_SEGMENT* cur_seg = NULL;
VTSI_FOOTER footer;
if (xstate->dst_dir)
bb_error_msg_and_err("decompress to dir is not supported");
src_fd = xstate->src_fd;
src_size = lseek(src_fd, 0, SEEK_END);
lseek(src_fd, src_size - sizeof(VTSI_FOOTER), SEEK_SET);
safe_read(src_fd, &footer, sizeof(footer));
if (!check_vtsi_footer(&footer))
goto err;
if (xstate->mem_output_size_max == 512)
max_buflen = 1024;
segment = xmalloc(footer.segment_num * sizeof(VTSI_SEGMENT) + max_buflen);
if (!segment)
bb_error_msg_and_err("Failed to alloc segment buffer %u", footer.segment_num);
buf = (uint8_t*)segment + footer.segment_num * sizeof(VTSI_SEGMENT);
lseek(src_fd, footer.segment_offset, SEEK_SET);
/* coverity[tainted_data_argument] */
safe_read(src_fd, segment, footer.segment_num * sizeof(VTSI_SEGMENT));
if (!check_vtsi_segment(&footer, segment))
goto err;
/* read data */
lseek(src_fd, 0, SEEK_SET);
for (seg = 0; seg < footer.segment_num; seg++) {
cur_seg = segment + seg;
datalen = (int64_t)cur_seg->sector_num * 512;
phy_offset = cur_seg->disk_start_sector * 512;
if (xstate->mem_output_size_max == 0 && xstate->dst_fd >= 0)
lseek(xstate->dst_fd, phy_offset, SEEK_SET);
while (datalen > 0) {
wsize = MIN((size_t)datalen, max_buflen);
safe_read(src_fd, buf, (unsigned int)wsize);
retval = transformer_write(xstate, buf, wsize);
if (retval != (ssize_t)wsize) {
n = (retval == -ENOSPC) ? xstate->mem_output_size_max : -1;
goto err;
}
tot += retval;
datalen -= wsize;
}
}
n = tot;
err:
if (segment)
free(segment);
return n;
}