int fdt_open_into()

in EmbeddedPkg/Library/FdtLib/fdt_rw.c [429:491]

• 48 lines of code
• 10 McCabe index (conditional complexity)

int fdt_open_into(const void *fdt, void *buf, int bufsize)
{
	int err;
	int mem_rsv_size, struct_size;
	int newsize;
	const char *fdtstart = fdt;
	const char *fdtend = fdtstart + fdt_totalsize(fdt);
	char *tmp;

	FDT_CHECK_HEADER(fdt);

	mem_rsv_size = (fdt_num_mem_rsv(fdt)+1)
		* sizeof(struct fdt_reserve_entry);

	if (fdt_version(fdt) >= 17) {
		struct_size = fdt_size_dt_struct(fdt);
	} else {
		struct_size = 0;
		while (fdt_next_tag(fdt, struct_size, &struct_size) != FDT_END)
			;
		if (struct_size < 0)
			return struct_size;
	}

	if (!_fdt_blocks_misordered(fdt, mem_rsv_size, struct_size)) {
		/* no further work necessary */
		err = fdt_move(fdt, buf, bufsize);
		if (err)
			return err;
		fdt_set_version(buf, 17);
		fdt_set_size_dt_struct(buf, struct_size);
		fdt_set_totalsize(buf, bufsize);
		return 0;
	}

	/* Need to reorder */
	newsize = FDT_ALIGN(sizeof(struct fdt_header), 8) + mem_rsv_size
		+ struct_size + fdt_size_dt_strings(fdt);

	if (bufsize < newsize)
		return -FDT_ERR_NOSPACE;

	/* First attempt to build converted tree at beginning of buffer */
	tmp = buf;
	/* But if that overlaps with the old tree... */
	if (((tmp + newsize) > fdtstart) && (tmp < fdtend)) {
		/* Try right after the old tree instead */
		tmp = (char *)(uintptr_t)fdtend;
		if ((tmp + newsize) > ((char *)buf + bufsize))
			return -FDT_ERR_NOSPACE;
	}

	_fdt_packblocks(fdt, tmp, mem_rsv_size, struct_size);
	memmove(buf, tmp, newsize);

	fdt_set_magic(buf, FDT_MAGIC);
	fdt_set_totalsize(buf, bufsize);
	fdt_set_version(buf, 17);
	fdt_set_last_comp_version(buf, 16);
	fdt_set_boot_cpuid_phys(buf, fdt_boot_cpuid_phys(fdt));

	return 0;
}