efi_status_t handle_cmdline_files()

in efi/libstub/file.c [130:250]

• 90 lines of code
• 18 McCabe index (conditional complexity)

efi_status_t handle_cmdline_files(efi_loaded_image_t *image,
				  const efi_char16_t *optstr,
				  int optstr_size,
				  unsigned long soft_limit,
				  unsigned long hard_limit,
				  unsigned long *load_addr,
				  unsigned long *load_size)
{
	const efi_char16_t *cmdline = image->load_options;
	int cmdline_len = image->load_options_size;
	unsigned long efi_chunk_size = ULONG_MAX;
	efi_file_protocol_t *volume = NULL;
	efi_file_protocol_t *file;
	unsigned long alloc_addr;
	unsigned long alloc_size;
	efi_status_t status;
	int offset;

	if (!load_addr || !load_size)
		return EFI_INVALID_PARAMETER;

	efi_apply_loadoptions_quirk((const void **)&cmdline, &cmdline_len);
	cmdline_len /= sizeof(*cmdline);

	if (IS_ENABLED(CONFIG_X86) && !efi_nochunk)
		efi_chunk_size = EFI_READ_CHUNK_SIZE;

	alloc_addr = alloc_size = 0;
	do {
		struct finfo fi;
		unsigned long size;
		void *addr;

		offset = find_file_option(cmdline, cmdline_len,
					  optstr, optstr_size,
					  fi.filename, ARRAY_SIZE(fi.filename));

		if (!offset)
			break;

		cmdline += offset;
		cmdline_len -= offset;

		if (!volume) {
			status = efi_open_volume(image, &volume);
			if (status != EFI_SUCCESS)
				return status;
		}

		status = efi_open_file(volume, &fi, &file, &size);
		if (status != EFI_SUCCESS)
			goto err_close_volume;

		/*
		 * Check whether the existing allocation can contain the next
		 * file. This condition will also trigger naturally during the
		 * first (and typically only) iteration of the loop, given that
		 * alloc_size == 0 in that case.
		 */
		if (round_up(alloc_size + size, EFI_ALLOC_ALIGN) >
		    round_up(alloc_size, EFI_ALLOC_ALIGN)) {
			unsigned long old_addr = alloc_addr;

			status = EFI_OUT_OF_RESOURCES;
			if (soft_limit < hard_limit)
				status = efi_allocate_pages(alloc_size + size,
							    &alloc_addr,
							    soft_limit);
			if (status == EFI_OUT_OF_RESOURCES)
				status = efi_allocate_pages(alloc_size + size,
							    &alloc_addr,
							    hard_limit);
			if (status != EFI_SUCCESS) {
				efi_err("Failed to allocate memory for files\n");
				goto err_close_file;
			}

			if (old_addr != 0) {
				/*
				 * This is not the first time we've gone
				 * around this loop, and so we are loading
				 * multiple files that need to be concatenated
				 * and returned in a single buffer.
				 */
				memcpy((void *)alloc_addr, (void *)old_addr, alloc_size);
				efi_free(alloc_size, old_addr);
			}
		}

		addr = (void *)alloc_addr + alloc_size;
		alloc_size += size;

		while (size) {
			unsigned long chunksize = min(size, efi_chunk_size);

			status = file->read(file, &chunksize, addr);
			if (status != EFI_SUCCESS) {
				efi_err("Failed to read file\n");
				goto err_close_file;
			}
			addr += chunksize;
			size -= chunksize;
		}
		file->close(file);
	} while (offset > 0);

	*load_addr = alloc_addr;
	*load_size = alloc_size;

	if (volume)
		volume->close(volume);
	return EFI_SUCCESS;

err_close_file:
	file->close(file);

err_close_volume:
	volume->close(volume);
	efi_free(alloc_size, alloc_addr);
	return status;
}