Differential D4277 Diff 10503 lib/libcasper/services/cap_random/cap_random.c

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lib/libcasper/services/cap_random/cap_random.c

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				/*-
				* Copyright (c) 2013 The FreeBSD Foundation
				* All rights reserved.
				*
				* This software was developed by Pawel Jakub Dawidek under sponsorship from
				* the FreeBSD Foundation.
				*
				* Redistribution and use in source and binary forms, with or without
				* modification, are permitted provided that the following conditions
				* are met:
				* 1. Redistributions of source code must retain the above copyright
				* notice, this list of conditions and the following disclaimer.
				* 2. Redistributions in binary form must reproduce the above copyright
				* notice, this list of conditions and the following disclaimer in the
				* documentation and/or other materials provided with the distribution.
				*
				* THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
				* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
				* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
				* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
				* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
				* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
				* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
				* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
				* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
				* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
				* SUCH DAMAGE.
				*/

				#include <sys/cdefs.h>
				__FBSDID("$FreeBSD$");

				#include <sys/nv.h>

				#include <assert.h>
				#include <errno.h>
				#include <stdio.h>
				#include <stdlib.h>
				#include <string.h>

				#include <libcasper.h>
				#include <libcasper_service.h>

				#include "cap_random.h"

				#define MAXSIZE (1024 * 1024)

				int
				cap_random_buf(cap_channel_t chan, void buf, size_t nbytes)
				{
				nvlist_t *nvl;
				const void *randbuf;
				uint8_t *ptr;
				size_t left, randbufsize;

				left = nbytes;
				ptr = buf;

				while (left > 0) {
				nvl = nvlist_create(0);
				nvlist_add_string(nvl, "cmd", "generate");
				nvlist_add_number(nvl, "size",
				(uint64_t)(left > MAXSIZE ? MAXSIZE : left));
				nvl = cap_xfer_nvlist(chan, nvl, 0);
				if (nvl == NULL)
				return (-1);
				if (nvlist_get_number(nvl, "error") != 0) {
				errno = (int)nvlist_get_number(nvl, "error");
				nvlist_destroy(nvl);
				return (-1);
				}

				randbuf = nvlist_get_binary(nvl, "data", &randbufsize);
				memcpy(ptr, randbuf, randbufsize);

				nvlist_destroy(nvl);

				ptr += randbufsize;
				assert(left >= randbufsize);
				left -= randbufsize;
				}

				return (0);
				}

				/*
				* Service functions.
				*/

				static int
				random_command(const char cmd, const nvlist_t limits __unused,
				nvlist_t nvlin, nvlist_t nvlout)
				{
				void *data;
				size_t size;

				if (strcmp(cmd, "generate") != 0)
				return (EINVAL);
				if (!nvlist_exists_number(nvlin, "size"))
				return (EINVAL);

				size = (size_t)nvlist_get_number(nvlin, "size");
				if (size == 0 \|\| size > MAXSIZE)
				return (EINVAL);

				data = malloc(size);
				if (data == NULL)
				return (ENOMEM);

				arc4random_buf(data, size);

				nvlist_move_binary(nvlout, "data", data, size);

				return (0);
				}

				CREATE_SERVICE("system.random", NULL, random_command);