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/* SPDX-License-Identifier: GPL-3.0-or-later */
#include "meta_writer.h"
#include "squashfs.h"
#include "util.h"
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <stdio.h>
typedef struct meta_block_t {
struct meta_block_t *next;
/* possibly compressed data with 2 byte header */
uint8_t data[SQFS_META_BLOCK_SIZE + 2];
} meta_block_t;
struct meta_writer_t {
/* A byte offset into the uncompressed data of the current block */
size_t offset;
/* The location of the current block in the file */
size_t block_offset;
/* The underlying file descriptor to write to */
int outfd;
/* A pointer to the compressor to use for compressing the data */
compressor_t *cmp;
/* The raw data chunk that data is appended to */
uint8_t data[SQFS_META_BLOCK_SIZE];
bool keep_in_mem;
meta_block_t *list;
meta_block_t *list_end;
};
static int write_block(int fd, meta_block_t *outblk)
{
size_t count = le16toh(((uint16_t *)outblk->data)[0]) & 0x7FFF;
return write_data("writing meta data block", fd,
outblk->data, count + 2);
}
meta_writer_t *meta_writer_create(int fd, compressor_t *cmp, bool keep_in_mem)
{
meta_writer_t *m = calloc(1, sizeof(*m));
if (m == NULL) {
perror("creating meta data writer");
return NULL;
}
m->cmp = cmp;
m->outfd = fd;
m->keep_in_mem = keep_in_mem;
return m;
}
void meta_writer_destroy(meta_writer_t *m)
{
meta_block_t *blk;
while (m->list != NULL) {
blk = m->list;
m->list = blk->next;
free(blk);
}
free(m);
}
int meta_writer_flush(meta_writer_t *m)
{
meta_block_t *outblk;
size_t count;
ssize_t ret;
if (m->offset == 0)
return 0;
outblk = calloc(1, sizeof(*outblk));
if (outblk == NULL) {
perror("generating meta data block");
return -1;
}
ret = m->cmp->do_block(m->cmp, m->data, m->offset,
outblk->data + 2, sizeof(outblk->data) - 2);
if (ret < 0) {
free(outblk);
return -1;
}
if (ret > 0) {
((uint16_t *)outblk->data)[0] = htole16(ret);
count = ret + 2;
} else {
((uint16_t *)outblk->data)[0] = htole16(m->offset | 0x8000);
memcpy(outblk->data + 2, m->data, m->offset);
count = m->offset + 2;
}
if (m->keep_in_mem) {
if (m->list == NULL) {
m->list = outblk;
} else {
m->list_end->next = outblk;
}
m->list_end = outblk;
ret = 0;
} else {
ret = write_block(m->outfd, outblk);
free(outblk);
}
memset(m->data, 0, sizeof(m->data));
m->offset = 0;
m->block_offset += count;
return ret;
}
int meta_writer_append(meta_writer_t *m, const void *data, size_t size)
{
size_t diff;
while (size != 0) {
diff = sizeof(m->data) - m->offset;
if (diff == 0) {
if (meta_writer_flush(m))
return -1;
diff = sizeof(m->data);
}
if (diff > size)
diff = size;
memcpy(m->data + m->offset, data, diff);
m->offset += diff;
size -= diff;
data = (const char *)data + diff;
}
if (m->offset == sizeof(m->data))
return meta_writer_flush(m);
return 0;
}
void meta_writer_get_position(const meta_writer_t *m, uint64_t *block_start,
uint32_t *offset)
{
*block_start = m->block_offset;
*offset = m->offset;
}
void meta_writer_reset(meta_writer_t *m)
{
m->block_offset = 0;
m->offset = 0;
}
int meta_write_write_to_file(meta_writer_t *m)
{
meta_block_t *blk;
while (m->list != NULL) {
blk = m->list;
if (write_block(m->outfd, blk))
return -1;
m->list = blk->next;
free(blk);
}
m->list_end = NULL;
return 0;
}
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