path: root/lib/sqfs/read_inode.c

/* SPDX-License-Identifier: GPL-3.0-or-later */
/*
 * read_inode.c
 *
 * Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
 */
#define SQFS_BUILDING_DLL
#include "config.h"

#include "sqfs/meta_reader.h"
#include "sqfs/error.h"
#include "sqfs/super.h"
#include "sqfs/inode.h"
#include "util.h"

#include <sys/stat.h>
#include <stdlib.h>
#include <errno.h>

#define SWAB16(x) x = le16toh(x)
#define SWAB32(x) x = le32toh(x)
#define SWAB64(x) x = le64toh(x)

static int set_mode(sqfs_inode_t *inode)
{
	inode->mode &= ~S_IFMT;

	switch (inode->type) {
	case SQFS_INODE_SOCKET:
	case SQFS_INODE_EXT_SOCKET:
		inode->mode |= S_IFSOCK;
		break;
	case SQFS_INODE_SLINK:
	case SQFS_INODE_EXT_SLINK:
		inode->mode |= S_IFLNK;
		break;
	case SQFS_INODE_FILE:
	case SQFS_INODE_EXT_FILE:
		inode->mode |= S_IFREG;
		break;
	case SQFS_INODE_BDEV:
	case SQFS_INODE_EXT_BDEV:
		inode->mode |= S_IFBLK;
		break;
	case SQFS_INODE_DIR:
	case SQFS_INODE_EXT_DIR:
		inode->mode |= S_IFDIR;
		break;
	case SQFS_INODE_CDEV:
	case SQFS_INODE_EXT_CDEV:
		inode->mode |= S_IFCHR;
		break;
	case SQFS_INODE_FIFO:
	case SQFS_INODE_EXT_FIFO:
		inode->mode |= S_IFIFO;
		break;
	default:
		return SQFS_ERROR_UNSUPPORTED;
	}

	return 0;
}

static uint64_t get_block_count(uint64_t size, uint64_t block_size,
				uint32_t frag_index, uint32_t frag_offset)
{
	uint64_t count = size / block_size;

	if ((size % block_size) != 0 &&
	    (frag_index == 0xFFFFFFFF || frag_offset == 0xFFFFFFFF)) {
		++count;
	}

	return count;
}

static int read_inode_file(sqfs_meta_reader_t *ir, sqfs_inode_t *base,
			   size_t block_size, sqfs_inode_generic_t **result)
{
	sqfs_inode_generic_t *out;
	sqfs_inode_file_t file;
	uint64_t i, count;
	int err;

	err = sqfs_meta_reader_read(ir, &file, sizeof(file));
	if (err)
		return err;

	SWAB32(file.blocks_start);
	SWAB32(file.fragment_index);
	SWAB32(file.fragment_offset);
	SWAB32(file.file_size);

	count = get_block_count(file.file_size, block_size,
				file.fragment_index, file.fragment_offset);

	out = alloc_flex(sizeof(*out), sizeof(uint32_t), count);
	if (out == NULL)
		return SQFS_ERROR_ALLOC;

	out->base = *base;
	out->data.file = file;
	out->block_sizes = (uint32_t *)out->extra;
	out->num_file_blocks = count;

	err = sqfs_meta_reader_read(ir, out->block_sizes,
				    count * sizeof(uint32_t));
	if (err) {
		free(out);
		return err;
	}

	for (i = 0; i < count; ++i)
		SWAB32(out->block_sizes[i]);

	*result = out;
	return 0;
}

static int read_inode_file_ext(sqfs_meta_reader_t *ir, sqfs_inode_t *base,
			       size_t block_size, sqfs_inode_generic_t **result)
{
	sqfs_inode_file_ext_t file;
	sqfs_inode_generic_t *out;
	uint64_t i, count;
	int err;

	err = sqfs_meta_reader_read(ir, &file, sizeof(file));
	if (err)
		return err;

	SWAB64(file.blocks_start);
	SWAB64(file.file_size);
	SWAB64(file.sparse);
	SWAB32(file.nlink);
	SWAB32(file.fragment_idx);
	SWAB32(file.fragment_offset);
	SWAB32(file.xattr_idx);

	count = get_block_count(file.file_size, block_size,
				file.fragment_idx, file.fragment_offset);

	out = alloc_flex(sizeof(*out), sizeof(uint32_t), count);
	if (out == NULL) {
		return errno == EOVERFLOW ? SQFS_ERROR_OVERFLOW :
			SQFS_ERROR_ALLOC;
	}

	out->base = *base;
	out->data.file_ext = file;
	out->block_sizes = (uint32_t *)out->extra;
	out->num_file_blocks = count;

	err = sqfs_meta_reader_read(ir, out->block_sizes,
				    count * sizeof(uint32_t));
	if (err) {
		free(out);
		return err;
	}

	for (i = 0; i < count; ++i)
		SWAB32(out->block_sizes[i]);

	*result = out;
	return 0;
}

static int read_inode_slink(sqfs_meta_reader_t *ir, sqfs_inode_t *base,
			    sqfs_inode_generic_t **result)
{
	sqfs_inode_generic_t *out;
	sqfs_inode_slink_t slink;
	size_t size;
	int err;

	err = sqfs_meta_reader_read(ir, &slink, sizeof(slink));
	if (err)
		return err;

	SWAB32(slink.nlink);
	SWAB32(slink.target_size);

	if (SZ_ADD_OV(slink.target_size, 1, &size) ||
	    SZ_ADD_OV(sizeof(*out), size, &size)) {
		return SQFS_ERROR_OVERFLOW;
	}

	out = calloc(1, size);
	if (out == NULL)
		return SQFS_ERROR_ALLOC;

	out->slink_target = (char *)out->extra;
	out->base = *base;
	out->data.slink = slink;

	err = sqfs_meta_reader_read(ir, out->slink_target, slink.target_size);
	if (err) {
		free(out);
		return err;
	}

	*result = out;
	return 0;
}

static int read_inode_slink_ext(sqfs_meta_reader_t *ir, sqfs_inode_t *base,
				sqfs_inode_generic_t **result)
{
	uint32_t xattr;
	int err;

	err = read_inode_slink(ir, base, result);
	if (err)
		return err;

	err = sqfs_meta_reader_read(ir, &xattr, sizeof(xattr));
	if (err) {
		free(*result);
		return err;
	}

	(*result)->data.slink_ext.xattr_idx = le32toh(xattr);
	return 0;
}

int sqfs_meta_reader_read_inode(sqfs_meta_reader_t *ir, sqfs_super_t *super,
				uint64_t block_start, size_t offset,
				sqfs_inode_generic_t **result)
{
	sqfs_inode_generic_t *out;
	sqfs_inode_t inode;
	int err;

	/* read base inode */
	block_start += super->inode_table_start;

	err = sqfs_meta_reader_seek(ir, block_start, offset);
	if (err)
		return err;

	err = sqfs_meta_reader_read(ir, &inode, sizeof(inode));
	if (err)
		return err;

	SWAB16(inode.type);
	SWAB16(inode.mode);
	SWAB16(inode.uid_idx);
	SWAB16(inode.gid_idx);
	SWAB32(inode.mod_time);
	SWAB32(inode.inode_number);

	err = set_mode(&inode);
	if (err)
		return err;

	/* inode types where the size is variable */
	switch (inode.type) {
	case SQFS_INODE_FILE:
		return read_inode_file(ir, &inode, super->block_size, result);
	case SQFS_INODE_SLINK:
		return read_inode_slink(ir, &inode, result);
	case SQFS_INODE_EXT_FILE:
		return read_inode_file_ext(ir, &inode, super->block_size,
					   result);
	case SQFS_INODE_EXT_SLINK:
		return read_inode_slink_ext(ir, &inode, result);
	default:
		break;
	}

	/* everything else */
	out = calloc(1, sizeof(*out));
	if (out == NULL)
		return SQFS_ERROR_ALLOC;

	out->base = inode;

	switch (inode.type) {
	case SQFS_INODE_DIR:
		err = sqfs_meta_reader_read(ir, &out->data.dir,
					    sizeof(out->data.dir));
		if (err)
			goto fail_free;

		SWAB32(out->data.dir.start_block);
		SWAB32(out->data.dir.nlink);
		SWAB16(out->data.dir.size);
		SWAB16(out->data.dir.offset);
		SWAB32(out->data.dir.parent_inode);
		break;
	case SQFS_INODE_BDEV:
	case SQFS_INODE_CDEV:
		err = sqfs_meta_reader_read(ir, &out->data.dev,
					    sizeof(out->data.dev));
		if (err)
			goto fail_free;
		SWAB32(out->data.dev.nlink);
		SWAB32(out->data.dev.devno);
		break;
	case SQFS_INODE_FIFO:
	case SQFS_INODE_SOCKET:
		err = sqfs_meta_reader_read(ir, &out->data.ipc,
					    sizeof(out->data.ipc));
		if (err)
			goto fail_free;
		SWAB32(out->data.ipc.nlink);
		break;
	case SQFS_INODE_EXT_DIR:
		err = sqfs_meta_reader_read(ir, &out->data.dir_ext,
					    sizeof(out->data.dir_ext));
		if (err)
			goto fail_free;
		SWAB32(out->data.dir_ext.nlink);
		SWAB32(out->data.dir_ext.size);
		SWAB32(out->data.dir_ext.start_block);
		SWAB32(out->data.dir_ext.parent_inode);
		SWAB16(out->data.dir_ext.inodex_count);
		SWAB16(out->data.dir_ext.offset);
		SWAB32(out->data.dir_ext.xattr_idx);
		break;
	case SQFS_INODE_EXT_BDEV:
	case SQFS_INODE_EXT_CDEV:
		err = sqfs_meta_reader_read(ir, &out->data.dev_ext,
					    sizeof(out->data.dev_ext));
		if (err)
			goto fail_free;
		SWAB32(out->data.dev_ext.nlink);
		SWAB32(out->data.dev_ext.devno);
		SWAB32(out->data.dev_ext.xattr_idx);
		break;
	case SQFS_INODE_EXT_FIFO:
	case SQFS_INODE_EXT_SOCKET:
		err = sqfs_meta_reader_read(ir, &out->data.ipc_ext,
					    sizeof(out->data.ipc_ext));
		if (err)
			goto fail_free;
		SWAB32(out->data.ipc_ext.nlink);
		SWAB32(out->data.ipc_ext.xattr_idx);
		break;
	default:
		return SQFS_ERROR_UNSUPPORTED;
	}

	*result = out;
	return 0;
fail_free:
	free(out);
	return err;
}