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/* SPDX-License-Identifier: GPL-3.0-or-later */
#include "unsquashfs.h"
int extract_file(file_info_t *fi, compressor_t *cmp, size_t block_size,
frag_reader_t *frag, int sqfsfd, int outfd)
{
void *buffer, *scratch, *ptr;
size_t i, count, fragsz;
bool compressed;
uint32_t bs;
ssize_t ret;
buffer = malloc(block_size * 2);
if (buffer == NULL) {
perror("allocating scratch buffer");
return -1;
}
scratch = (char *)buffer + block_size;
count = fi->size / block_size;
if (count > 0) {
if (lseek(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 > block_size)
goto fail_bs;
ret = read_retry(sqfsfd, buffer, bs);
if (ret < 0)
goto fail_rd;
if ((size_t)ret < bs)
goto fail_trunc;
if (compressed) {
ret = cmp->do_block(cmp, buffer, bs,
scratch, block_size);
if (ret <= 0)
goto fail;
bs = ret;
ptr = scratch;
} else {
ptr = 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 % block_size;
if (fragsz > 0) {
if (frag_reader_read(frag, fi->fragment, fi->fragment_offset,
buffer, fragsz)) {
goto fail;
}
ret = write_retry(outfd, buffer, fragsz);
if (ret < 0)
goto fail_wr;
if ((size_t)ret < fragsz)
goto fail_wr_trunc;
}
free(buffer);
return 0;
fail_seek:
perror("seek on squashfs");
goto fail;
fail_wr:
perror("writing uncompressed block");
goto fail;
fail_wr_trunc:
fputs("writing uncompressed block: truncated write\n", stderr);
goto fail;
fail_rd:
perror("reading from squashfs");
goto fail;
fail_trunc:
fputs("reading from squashfs: unexpected end of file\n", stderr);
goto fail;
fail_bs:
fputs("found compressed block larger than block size\n", stderr);
goto fail;
fail:
free(buffer);
return -1;
}
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