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, 141 insertions, 0 deletions

diff --git a/lib/sqfshelper/write_dir.c b/lib/sqfshelper/write_dir.c
new file mode 100644
index 0000000..23297ad
--- /dev/null
+++ b/lib/sqfshelper/write_dir.c
@@ -0,0 +1,141 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+/*
+ * write_dir.c
+ *
+ * Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
+ */
+#include "config.h"
+
+#include "meta_writer.h"
+#include "util.h"
+
+#include <assert.h>
+#include <endian.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+
+static int get_type(mode_t mode)
+{
+	switch (mode & S_IFMT) {
+	case S_IFSOCK: return SQFS_INODE_SOCKET;
+	case S_IFIFO:  return SQFS_INODE_FIFO;
+	case S_IFLNK:  return SQFS_INODE_SLINK;
+	case S_IFBLK:  return SQFS_INODE_BDEV;
+	case S_IFCHR:  return SQFS_INODE_CDEV;
+	case S_IFDIR:  return SQFS_INODE_DIR;
+	case S_IFREG:  return SQFS_INODE_FILE;
+	default:
+		assert(0);
+	}
+}
+
+static int dir_index_grow(dir_index_t **index)
+{
+	size_t size = sizeof(dir_index_t) + sizeof(idx_ref_t) * 10;
+	void *new;
+
+	if (*index == NULL) {
+		new = calloc(1, size);
+	} else {
+		if ((*index)->num_nodes < (*index)->max_nodes)
+			return 0;
+
+		size += sizeof(idx_ref_t) * (*index)->num_nodes;
+		new = realloc(*index, size);
+	}
+
+	if (new == NULL) {
+		perror("creating directory index");
+		return -1;
+	}
+
+	*index = new;
+	(*index)->max_nodes += 10;
+	return 0;
+}
+
+int meta_writer_write_dir(meta_writer_t *dm, dir_info_t *dir,
+			  dir_index_t **index)
+{
+	size_t i, size, count;
+	sqfs_dir_header_t hdr;
+	sqfs_dir_entry_t ent;
+	tree_node_t *c, *d;
+	uint16_t *diff_u16;
+	uint32_t offset;
+	uint64_t block;
+	int32_t diff;
+
+	c = dir->children;
+	dir->size = 0;
+
+	meta_writer_get_position(dm, &dir->start_block, &dir->block_offset);
+
+	while (c != NULL) {
+		meta_writer_get_position(dm, &block, &offset);
+
+		count = 0;
+		size = (offset + sizeof(hdr)) % SQFS_META_BLOCK_SIZE;
+
+		for (d = c; d != NULL; d = d->next) {
+			if ((d->inode_ref >> 16) != (c->inode_ref >> 16))
+				break;
+
+			diff = d->inode_num - c->inode_num;
+
+			if (diff > 32767 || diff < -32767)
+				break;
+
+			size += sizeof(ent) + strlen(c->name);
+
+			if (count > 0 && size > SQFS_META_BLOCK_SIZE)
+				break;
+
+			count += 1;
+		}
+
+		if (count > SQFS_MAX_DIR_ENT)
+			count = SQFS_MAX_DIR_ENT;
+
+		if (dir_index_grow(index))
+			return -1;
+
+		meta_writer_get_position(dm, &block, &offset);
+
+		i = (*index)->num_nodes++;
+		(*index)->idx_nodes[i].node = c;
+		(*index)->idx_nodes[i].block = block;
+		(*index)->idx_nodes[i].index = dir->size;
+
+		hdr.count = htole32(count - 1);
+		hdr.start_block = htole32(c->inode_ref >> 16);
+		hdr.inode_number = htole32(c->inode_num);
+		dir->size += sizeof(hdr);
+
+		if (meta_writer_append(dm, &hdr, sizeof(hdr)))
+			return -1;
+
+		d = c;
+
+		for (i = 0; i < count; ++i) {
+			ent.inode_diff = c->inode_num - d->inode_num;
+
+			diff_u16 = (uint16_t *)&ent.inode_diff;
+			*diff_u16 = htole16(*diff_u16);
+
+			ent.offset = htole16(c->inode_ref & 0x0000FFFF);
+			ent.type = htole16(get_type(c->mode));
+			ent.size = htole16(strlen(c->name) - 1);
+			dir->size += sizeof(ent) + strlen(c->name);
+
+			if (meta_writer_append(dm, &ent, sizeof(ent)))
+				return -1;
+			if (meta_writer_append(dm, c->name, strlen(c->name)))
+				return -1;
+
+			c = c->next;
+		}
+	}
+	return 0;
+}