Split libsquashfs.a into low seperate libraries

The idea is to make libsquashfs.a independend of libfstree.a, so it becomes
a general purpose squashfs manipulation library. All the high level glue code
for libfstree.a and utilites that are overly specific with to tools are moved
to a seperate librarby.

This commit makes the first step by moving the stuff with dependencies on
libfstree to a seperate library.

Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>

1 files changed, 528 insertions, 0 deletions

diff --git a/lib/sqfshelper/data_writer.c b/lib/sqfshelper/data_writer.c
new file mode 100644
index 0000000..d4b402b
--- /dev/null
+++ b/lib/sqfshelper/data_writer.c
@@ -0,0 +1,528 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+/*
+ * data_writer.c
+ *
+ * Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
+ */
+#include "config.h"
+
+#include "block_processor.h"
+#include "data_writer.h"
+#include "highlevel.h"
+#include "util.h"
+
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <errno.h>
+#include <zlib.h>
+
+struct data_writer_t {
+	block_t *frag_block;
+	sqfs_fragment_t *fragments;
+	size_t num_fragments;
+	size_t max_fragments;
+
+	size_t devblksz;
+	uint64_t bytes_written;
+	off_t start;
+
+	block_processor_t *proc;
+	compressor_t *cmp;
+	file_info_t *list;
+	sqfs_super_t *super;
+	int outfd;
+};
+
+enum {
+	BLK_FIRST_BLOCK = BLK_USER,
+	BLK_LAST_BLOCK = BLK_USER << 1,
+	BLK_ALLIGN = BLK_USER << 2,
+	BLK_FRAGMENT_BLOCK = BLK_USER << 3,
+};
+
+static int save_position(data_writer_t *data)
+{
+	data->bytes_written = data->super->bytes_used;
+	data->start = lseek(data->outfd, 0, SEEK_CUR);
+
+	if (data->start == (off_t)-1) {
+		perror("querying current position on squashfs image");
+		return -1;
+	}
+
+	return 0;
+}
+
+static int restore_position(data_writer_t *data)
+{
+	if (lseek(data->outfd, data->start, SEEK_SET) == (off_t)-1)
+		goto fail_seek;
+
+	if (ftruncate(data->outfd, data->start))
+		goto fail_truncate;
+
+	data->super->bytes_used = data->bytes_written;
+	return 0;
+fail_seek:
+	perror("seeking on squashfs image after file deduplication");
+	return -1;
+fail_truncate:
+	perror("truncating squashfs image after file deduplication");
+	return -1;
+}
+
+static int allign_file(data_writer_t *data)
+{
+	size_t diff = data->super->bytes_used % data->devblksz;
+
+	if (diff == 0)
+		return 0;
+
+	if (padd_file(data->outfd, data->super->bytes_used, data->devblksz))
+		return -1;
+
+	data->super->bytes_used += data->devblksz - diff;
+	return 0;
+}
+
+static int block_callback(void *user, block_t *blk)
+{
+	file_info_t *fi = blk->user;
+	data_writer_t *data = user;
+	uint64_t ref, offset;
+	uint32_t out;
+
+	if (blk->flags & BLK_FIRST_BLOCK) {
+		if (save_position(data))
+			return -1;
+
+		if ((blk->flags & BLK_ALLIGN) && allign_file(data) != 0)
+			return -1;
+
+		fi->startblock = data->super->bytes_used;
+	}
+
+	if (blk->size == 0)
+		goto skip_sentinel;
+
+	out = blk->size;
+	if (!(blk->flags & BLK_IS_COMPRESSED))
+		out |= 1 << 24;
+
+	if (blk->flags & BLK_FRAGMENT_BLOCK) {
+		offset = htole64(data->super->bytes_used);
+		data->fragments[blk->index].start_offset = offset;
+		data->fragments[blk->index].pad0 = 0;
+		data->fragments[blk->index].size = htole32(out);
+
+		data->super->flags &= ~SQFS_FLAG_NO_FRAGMENTS;
+		data->super->flags |= SQFS_FLAG_ALWAYS_FRAGMENTS;
+	} else {
+		fi->blocks[blk->index].chksum = blk->checksum;
+		fi->blocks[blk->index].size = htole32(out);
+	}
+
+	if (write_data("writing data block", data->outfd,
+		       blk->data, blk->size)) {
+		return -1;
+	}
+
+	data->super->bytes_used += blk->size;
+
+skip_sentinel:
+	if (blk->flags & BLK_LAST_BLOCK) {
+		if ((blk->flags & BLK_ALLIGN) && allign_file(data) != 0)
+			return -1;
+
+		ref = find_equal_blocks(fi, data->list,
+					data->super->block_size);
+		if (ref > 0) {
+			fi->startblock = ref;
+			fi->flags |= FILE_FLAG_BLOCKS_ARE_DUPLICATE;
+
+			if (restore_position(data))
+				return -1;
+		}
+	}
+
+	return 0;
+}
+
+/*****************************************************************************/
+
+static int flush_fragment_block(data_writer_t *data)
+{
+	size_t newsz;
+	void *new;
+	int ret;
+
+	if (data->num_fragments == data->max_fragments) {
+		newsz = data->max_fragments ? data->max_fragments * 2 : 16;
+		new = realloc(data->fragments,
+			      sizeof(data->fragments[0]) * newsz);
+
+		if (new == NULL) {
+			perror("appending to fragment table");
+			return -1;
+		}
+
+		data->max_fragments = newsz;
+		data->fragments = new;
+	}
+
+	data->frag_block->index = data->num_fragments++;
+
+	ret = block_processor_enqueue(data->proc, data->frag_block);
+	data->frag_block = NULL;
+	return ret;
+}
+
+static int store_fragment(data_writer_t *data, block_t *frag)
+{
+	file_info_t *fi = frag->user;
+	size_t size;
+
+	if (data->frag_block != NULL) {
+		size = data->frag_block->size + frag->size;
+
+		if (size > data->super->block_size) {
+			if (flush_fragment_block(data))
+				goto fail;
+		}
+	}
+
+	if (data->frag_block == NULL) {
+		size = sizeof(block_t) + data->super->block_size;
+
+		data->frag_block = calloc(1, size);
+		if (data->frag_block == NULL) {
+			perror("creating fragment block");
+			goto fail;
+		}
+
+		data->frag_block->flags = BLK_DONT_CHECKSUM;
+		data->frag_block->flags |= BLK_FRAGMENT_BLOCK;
+	}
+
+	fi->fragment_offset = data->frag_block->size;
+	fi->fragment = data->num_fragments;
+
+	data->frag_block->flags |= (frag->flags & BLK_DONT_COMPRESS);
+	memcpy(data->frag_block->data + data->frag_block->size,
+	       frag->data, frag->size);
+
+	data->frag_block->size += frag->size;
+	free(frag);
+	return 0;
+fail:
+	free(frag);
+	return -1;
+}
+
+static bool is_zero_block(unsigned char *ptr, size_t size)
+{
+	return ptr[0] == 0 && memcmp(ptr, ptr + 1, size - 1) == 0;
+}
+
+static int handle_fragment(data_writer_t *data, block_t *blk)
+{
+	file_info_t *fi = blk->user, *ref;
+
+	fi->fragment_chksum = crc32(0, blk->data, blk->size);
+
+	ref = fragment_by_chksum(fi, fi->fragment_chksum, blk->size,
+				 data->list, data->super->block_size);
+
+	if (ref != NULL) {
+		fi->fragment_offset = ref->fragment_offset;
+		fi->fragment = ref->fragment;
+		fi->flags |= FILE_FLAG_FRAGMENT_IS_DUPLICATE;
+		free(blk);
+		return 0;
+	}
+
+	return store_fragment(data, blk);
+}
+
+static int add_sentinel_block(data_writer_t *data, file_info_t *fi,
+			      uint32_t flags)
+{
+	block_t *blk = calloc(1, sizeof(*blk));
+
+	if (blk == NULL) {
+		perror("creating sentinel block");
+		return -1;
+	}
+
+	blk->user = fi;
+	blk->flags = BLK_DONT_COMPRESS | BLK_DONT_CHECKSUM | flags;
+
+	return block_processor_enqueue(data->proc, blk);
+}
+
+int write_data_from_fd(data_writer_t *data, file_info_t *fi,
+		       int infd, int flags)
+{
+	uint32_t blk_flags = BLK_FIRST_BLOCK;
+	uint64_t file_size = fi->size;
+	size_t diff, i = 0;
+	block_t *blk;
+
+	if (flags & DW_DONT_COMPRESS)
+		blk_flags |= BLK_DONT_COMPRESS;
+
+	if (flags & DW_ALLIGN_DEVBLK)
+		blk_flags |= BLK_ALLIGN;
+
+	fi->next = data->list;
+	data->list = fi;
+
+	for (; file_size > 0; file_size -= diff) {
+		if (file_size > data->super->block_size) {
+			diff = data->super->block_size;
+		} else {
+			diff = file_size;
+		}
+
+		blk = create_block(fi->input_file, infd, diff, fi, blk_flags);
+		if (blk == NULL)
+			return -1;
+
+		blk->index = i++;
+
+		if (is_zero_block(blk->data, blk->size)) {
+			fi->blocks[blk->index].chksum = 0;
+			fi->blocks[blk->index].size = 0;
+			free(blk);
+			continue;
+		}
+
+		if (diff < data->super->block_size &&
+		    !(flags & DW_DONT_FRAGMENT)) {
+			fi->flags |= FILE_FLAG_HAS_FRAGMENT;
+
+			if (!(blk_flags & (BLK_FIRST_BLOCK | BLK_LAST_BLOCK))) {
+				blk_flags |= BLK_LAST_BLOCK;
+
+				if (add_sentinel_block(data, fi, blk_flags)) {
+					free(blk);
+					return -1;
+				}
+			}
+
+			if (handle_fragment(data, blk))
+				return -1;
+		} else {
+			if (block_processor_enqueue(data->proc, blk))
+				return -1;
+
+			blk_flags &= ~BLK_FIRST_BLOCK;
+		}
+	}
+
+	if (!(blk_flags & (BLK_FIRST_BLOCK | BLK_LAST_BLOCK))) {
+		blk_flags |= BLK_LAST_BLOCK;
+
+		if (add_sentinel_block(data, fi, blk_flags))
+			return -1;
+	}
+
+	return 0;
+}
+
+static int check_map_valid(const sparse_map_t *map, file_info_t *fi)
+{
+	const sparse_map_t *m;
+	uint64_t offset;
+
+	if (map != NULL) {
+		offset = map->offset;
+
+		for (m = map; m != NULL; m = m->next) {
+			if (m->offset < offset)
+				goto fail_map;
+			offset = m->offset + m->count;
+		}
+
+		if (offset > fi->size)
+			goto fail_map_size;
+	}
+
+	return 0;
+fail_map_size:
+	fprintf(stderr, "%s: sparse file map spans beyond file size\n",
+		fi->input_file);
+	return -1;
+fail_map:
+	fprintf(stderr,
+		"%s: sparse file map is unordered or self overlapping\n",
+		fi->input_file);
+	return -1;
+}
+
+static int get_sparse_block(block_t *blk, file_info_t *fi, int infd,
+			    sparse_map_t **sparse_map, uint64_t offset,
+			    size_t diff)
+{
+	sparse_map_t *map = *sparse_map;
+	size_t start, count;
+
+	while (map != NULL && map->offset < offset + diff) {
+		start = 0;
+		count = map->count;
+
+		if (map->offset < offset)
+			count -= offset - map->offset;
+
+		if (map->offset > offset)
+			start = map->offset - offset;
+
+		if (start + count > diff)
+			count = diff - start;
+
+		if (read_data(fi->input_file, infd, blk->data + start, count))
+			return -1;
+
+		map = map->next;
+	}
+
+	*sparse_map = map;
+	return 0;
+}
+
+int write_data_from_fd_condensed(data_writer_t *data, file_info_t *fi,
+				 int infd, sparse_map_t *map, int flags)
+{
+	uint32_t blk_flags = BLK_FIRST_BLOCK;
+	size_t diff, i = 0;
+	uint64_t offset;
+	block_t *blk;
+
+	if (check_map_valid(map, fi))
+		return -1;
+
+	if (flags & DW_DONT_COMPRESS)
+		blk_flags |= BLK_DONT_COMPRESS;
+
+	if (flags & DW_ALLIGN_DEVBLK)
+		blk_flags |= BLK_ALLIGN;
+
+	for (offset = 0; offset < fi->size; offset += diff) {
+		if (fi->size - offset > (uint64_t)data->super->block_size) {
+			diff = data->super->block_size;
+		} else {
+			diff = fi->size - offset;
+		}
+
+		blk = alloc_flex(sizeof(*blk), 1, diff);
+		blk->size = diff;
+		blk->index = i++;
+		blk->user = fi;
+		blk->flags = blk_flags;
+
+		if (get_sparse_block(blk, fi, infd, &map, offset, diff)) {
+			free(blk);
+			return -1;
+		}
+
+		if (is_zero_block(blk->data, blk->size)) {
+			fi->blocks[blk->index].chksum = 0;
+			fi->blocks[blk->index].size = 0;
+			free(blk);
+			continue;
+		}
+
+		if (diff < data->super->block_size &&
+		    !(flags & DW_DONT_FRAGMENT)) {
+			fi->flags |= FILE_FLAG_HAS_FRAGMENT;
+
+			if (!(blk_flags & (BLK_FIRST_BLOCK | BLK_LAST_BLOCK))) {
+				blk_flags |= BLK_LAST_BLOCK;
+
+				if (add_sentinel_block(data, fi, blk_flags)) {
+					free(blk);
+					return -1;
+				}
+			}
+
+			if (handle_fragment(data, blk))
+				return -1;
+		} else {
+			if (block_processor_enqueue(data->proc, blk))
+				return -1;
+
+			blk_flags &= ~BLK_FIRST_BLOCK;
+		}
+	}
+
+	if (!(blk_flags & (BLK_FIRST_BLOCK | BLK_LAST_BLOCK))) {
+		blk_flags |= BLK_LAST_BLOCK;
+
+		if (add_sentinel_block(data, fi, blk_flags))
+			return -1;
+	}
+
+	return 0;
+}
+
+data_writer_t *data_writer_create(sqfs_super_t *super, compressor_t *cmp,
+				  int outfd, size_t devblksize,
+				  unsigned int num_jobs)
+{
+	data_writer_t *data = calloc(1, sizeof(*data));
+
+	if (data == NULL) {
+		perror("creating data writer");
+		return NULL;
+	}
+
+	data->proc = block_processor_create(super->block_size, cmp, num_jobs,
+					    data, block_callback);
+	data->cmp = cmp;
+	data->super = super;
+	data->outfd = outfd;
+	data->devblksz = devblksize;
+	return data;
+}
+
+void data_writer_destroy(data_writer_t *data)
+{
+	block_processor_destroy(data->proc);
+	free(data->fragments);
+	free(data);
+}
+
+int data_writer_write_fragment_table(data_writer_t *data)
+{
+	uint64_t start;
+	size_t size;
+	int ret;
+
+	if (data->num_fragments == 0) {
+		data->super->fragment_entry_count = 0;
+		data->super->fragment_table_start = 0xFFFFFFFFFFFFFFFFUL;
+		return 0;
+	}
+
+	size = sizeof(data->fragments[0]) * data->num_fragments;
+	ret = sqfs_write_table(data->outfd, data->super, data->cmp,
+			       data->fragments, size, &start);
+	if (ret)
+		return -1;
+
+	data->super->fragment_entry_count = data->num_fragments;
+	data->super->fragment_table_start = start;
+	return 0;
+}
+
+int data_writer_sync(data_writer_t *data)
+{
+	if (data->frag_block != NULL) {
+		if (flush_fragment_block(data))
+			return -1;
+	}
+
+	return block_processor_finish(data->proc);
+}