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/* SPDX-License-Identifier: GPL-3.0-or-later */
#include "config.h"
#include "data_reader.h"
#include "highlevel.h"
#include "util.h"
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <stdio.h>
struct data_reader_t {
sqfs_fragment_t *frag;
size_t num_fragments;
size_t current_frag_index;
size_t frag_used;
compressor_t *cmp;
size_t block_size;
int sqfsfd;
void *buffer;
void *scratch;
void *frag_block;
};
data_reader_t *data_reader_create(int fd, sqfs_super_t *super,
compressor_t *cmp)
{
data_reader_t *data = calloc(1, sizeof(*data) + 3 * super->block_size);
size_t i, size;
if (data == NULL) {
perror("creating data reader");
return data;
}
data->num_fragments = super->fragment_entry_count;
data->current_frag_index = super->fragment_entry_count;
data->buffer = (char *)data + sizeof(*data);
data->scratch = (char *)data->buffer + super->block_size;
data->frag_block = (char *)data->scratch + super->block_size;
data->sqfsfd = fd;
data->block_size = super->block_size;
data->cmp = cmp;
if (super->fragment_entry_count == 0 ||
(super->flags & SQFS_FLAG_NO_FRAGMENTS) != 0) {
return 0;
}
if (super->fragment_table_start >= super->bytes_used) {
fputs("Fragment table start is past end of file\n", stderr);
free(data);
return NULL;
}
size = sizeof(data->frag[0]) * data->num_fragments;
data->frag = sqfs_read_table(fd, cmp, size,
super->fragment_table_start);
if (data->frag == NULL) {
free(data);
return NULL;
}
for (i = 0; i < data->num_fragments; ++i) {
data->frag[i].size = le32toh(data->frag[i].size);
data->frag[i].start_offset =
le64toh(data->frag[i].start_offset);
}
return data;
}
void data_reader_destroy(data_reader_t *data)
{
free(data->frag);
free(data);
}
static int dump_blocks(data_reader_t *data, file_info_t *fi, int outfd,
bool allow_sparse, size_t count)
{
off_t sqfs_location = fi->startblock;
size_t i, unpackedsz;
uint64_t filesz = 0;
bool compressed;
uint32_t bs;
ssize_t ret;
void *ptr;
for (i = 0; i < count; ++i) {
bs = fi->blocks[i].size;
compressed = (bs & (1 << 24)) == 0;
bs &= (1 << 24) - 1;
if (bs > data->block_size)
goto fail_bs;
if ((fi->size - filesz) < (uint64_t)data->block_size) {
unpackedsz = fi->size - filesz;
} else {
unpackedsz = data->block_size;
}
filesz += unpackedsz;
if (bs == 0 && allow_sparse) {
if (ftruncate(outfd, filesz))
goto fail_sparse;
if (lseek(outfd, 0, SEEK_END) == (off_t)-1)
goto fail_sparse;
continue;
}
if (bs == 0) {
memset(data->buffer, 0, unpackedsz);
compressed = false;
} else {
if (read_data_at("reading data block", sqfs_location,
data->sqfsfd, data->buffer, bs)) {
return -1;
}
sqfs_location += bs;
}
if (compressed) {
ret = data->cmp->do_block(data->cmp, data->buffer, bs,
data->scratch,
data->block_size);
if (ret <= 0)
return -1;
ptr = data->scratch;
} else {
ptr = data->buffer;
}
if (write_data("writing uncompressed block",
outfd, ptr, unpackedsz)) {
return -1;
}
}
return 0;
fail_sparse:
perror("creating sparse output file");
return -1;
fail_bs:
fputs("found compressed block larger than block size\n", stderr);
return -1;
}
static int precache_fragment_block(data_reader_t *data, size_t idx)
{
bool compressed;
size_t size;
ssize_t ret;
if (idx == data->current_frag_index)
return 0;
if (idx >= data->num_fragments) {
fputs("fragment index out of bounds\n", stderr);
return -1;
}
compressed = (data->frag[idx].size & (1 << 24)) == 0;
size = data->frag[idx].size & ((1 << 24) - 1);
if (size > data->block_size) {
fputs("found fragment block larger than block size\n", stderr);
return -1;
}
if (read_data_at("reading fragments", data->frag[idx].start_offset,
data->sqfsfd, data->buffer, size)) {
return -1;
}
if (compressed) {
ret = data->cmp->do_block(data->cmp, data->buffer, size,
data->frag_block, data->block_size);
if (ret <= 0) {
fputs("extracting fragment block failed\n", stderr);
return -1;
}
size = ret;
} else {
memcpy(data->frag_block, data->buffer, size);
}
data->current_frag_index = idx;
data->frag_used = size;
return 0;
}
int data_reader_dump_file(data_reader_t *data, file_info_t *fi, int outfd,
bool allow_sparse)
{
size_t fragsz = fi->size % data->block_size;
size_t count = fi->size / data->block_size;
if (fragsz != 0 && !(fi->flags & FILE_FLAG_HAS_FRAGMENT)) {
fragsz = 0;
++count;
}
if (dump_blocks(data, fi, outfd, allow_sparse, count))
return -1;
if (fragsz > 0) {
if (precache_fragment_block(data, fi->fragment))
return -1;
if (fi->fragment_offset >= data->frag_used)
goto fail_range;
if ((fi->fragment_offset + fragsz - 1) >= data->frag_used)
goto fail_range;
if (write_data("writing uncompressed fragment", outfd,
(char *)data->frag_block + fi->fragment_offset,
fragsz)) {
return -1;
}
}
return 0;
fail_range:
fputs("attempted to read past fragment block limits\n", stderr);
return -1;
}
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