common/zircon_boot_args.c

/*
 * Copyright (c) 2020 The Fuchsia Authors
 */

#include <common.h>
#include <stdlib.h>
#include <zircon_uboot/boot_args.h>
#include <zircon_uboot/zircon.h>

static char *args = NULL;
static uint32_t args_len = 0;
// Chosen arbitrarily to make overflow checking easier so that we won't "wrap
// around" a uint32_t more than once. Can increase if needed.
#define MAX_ARG_LEN 2048

int zircon_store_cmdline(const char *payload)
{
	if (!payload) {
		return -1;
	}

	size_t length = strlen(payload);

	if (length == 0) {
		return -1;
	}
	if (length > MAX_ARG_LEN) {
		printf("Error: arg is too big\n");
		return -1;
	}

	uint32_t new_args_len;
	if (args) {
		// a ' ' is inserted after previous args
		new_args_len = args_len + length + 1;
	} else {
		new_args_len = length;
	}

	// Make sure new_args_len didn't overflow.
	if (new_args_len < args_len) {
		printf("Error: can't fit this arg\n");
		return -1;
	}

	char *new_args = malloc((size_t)new_args_len + 1);
	if (!new_args) {
		return -1;
	}
	new_args[new_args_len] = '\0';

	if (args) {
		memcpy(new_args, args, args_len);
		free(args);

		new_args[args_len] = ' ';
		memcpy(new_args + args_len + 1, payload, length);
	} else {
		memcpy(new_args, payload, length);
	}

	args_len = new_args_len;
	args = new_args;

	printf("args: %s, args_len: %u\n", args, args_len);
	return 0;
}

int zircon_clear_stored_cmdline(void)
{
	if (args) {
		free(args);
		args = NULL;
	}
	args_len = 0;
	return 0;
}

int zircon_append_cmdline(zbi_header_t *zbi, size_t capacity)
{
	int ret = 0;

	if (args) {
		ret = append_zbi_item_or_log(zbi, capacity, ZBI_TYPE_CMDLINE, 0,
					     args, args_len + 1);
		free(args);
		args = NULL;
		args_len = 0;
	}

	return ret;
}