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/* SPDX-License-Identifier: GPL-3.0-or-later */
#include "data_reader.h"
#include "frag_reader.h"
#include "util.h"
#include <stdlib.h>
#include <unistd.h>
#include <stdio.h>
struct data_reader_t {
compressor_t *cmp;
size_t block_size;
frag_reader_t *frag;
int sqfsfd;
void *buffer;
void *scratch;
};
data_reader_t *data_reader_create(int fd, sqfs_super_t *super,
compressor_t *cmp)
{
data_reader_t *data = calloc(1, sizeof(*data) + 2 * super->block_size);
if (data == NULL) {
perror("creating data reader");
return data;
}
if (super->fragment_entry_count > 0 &&
!(super->flags & SQFS_FLAG_NO_FRAGMENTS)) {
if (super->fragment_table_start >= super->bytes_used) {
fputs("Fragment table start is past end of file\n",
stderr);
free(data);
return NULL;
}
data->frag = frag_reader_create(super, fd, cmp);
if (data->frag == NULL) {
free(data);
return NULL;
}
}
data->buffer = (char *)data + sizeof(*data);
data->scratch = (char *)data->buffer + super->block_size;
data->sqfsfd = fd;
data->block_size = super->block_size;
data->cmp = cmp;
return data;
}
void data_reader_destroy(data_reader_t *data)
{
if (data->frag != NULL)
frag_reader_destroy(data->frag);
free(data);
}
int data_reader_dump_file(data_reader_t *data, file_info_t *fi, int outfd)
{
size_t i, count, fragsz;
bool compressed;
uint32_t bs;
ssize_t ret;
void *ptr;
count = fi->size / data->block_size;
if (count > 0) {
if (lseek(data->sqfsfd, fi->startblock, SEEK_SET) == (off_t)-1)
goto fail_seek;
for (i = 0; i < count; ++i) {
bs = fi->blocksizes[i];
compressed = (bs & (1 << 24)) == 0;
bs &= (1 << 24) - 1;
if (bs > data->block_size)
goto fail_bs;
ret = read_retry(data->sqfsfd, data->buffer, bs);
if (ret < 0)
goto fail_rd;
if ((size_t)ret < bs)
goto fail_trunc;
if (compressed) {
ret = data->cmp->do_block(data->cmp,
data->buffer, bs,
data->scratch,
data->block_size);
if (ret <= 0)
return -1;
bs = ret;
ptr = data->scratch;
} else {
ptr = data->buffer;
}
ret = write_retry(outfd, ptr, bs);
if (ret < 0)
goto fail_wr;
if ((size_t)ret < bs)
goto fail_wr_trunc;
}
}
fragsz = fi->size % data->block_size;
if (fragsz > 0) {
if (data->frag == NULL)
goto fail_frag;
if (frag_reader_read(data->frag, fi->fragment,
fi->fragment_offset, data->buffer,
fragsz)) {
return -1;
}
ret = write_retry(outfd, data->buffer, fragsz);
if (ret < 0)
goto fail_wr;
if ((size_t)ret < fragsz)
goto fail_wr_trunc;
}
return 0;
fail_seek:
perror("seek on squashfs");
return -1;
fail_wr:
perror("writing uncompressed block");
return -1;
fail_wr_trunc:
fputs("writing uncompressed block: truncated write\n", stderr);
return -1;
fail_rd:
perror("reading from squashfs");
return -1;
fail_trunc:
fputs("reading from squashfs: unexpected end of file\n", stderr);
return -1;
fail_bs:
fputs("found compressed block larger than block size\n", stderr);
return -1;
fail_frag:
fputs("file not a multiple of block size but no fragments available\n",
stderr);
return -1;
}
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