Re: [Minios-devel] [UNIKRAFT PATCH v2 1/1] lib/ukswrand: Add /dev/random and /dev/urandom

[Costin Lupu <costin.lup@xxxxxxxxx>]

Thanks, Vlad!

Reviewed-by: Costin Lupu <costin.lupu@xxxxxxxxx>

On 6/13/19 7:24 PM, Vlad-Andrei BĂDOIU (78692) wrote:
> This patch adds the /dev/random and /dev/urandom devices. Since we do not have
> any entropy generating function both devices share the same handlers. The
> registration of the devices is guarded by the config option CONFIG_DEV_RANDOM.
> 
> Signed-off-by: Vlad-Andrei Badoiu <vlad_andrei.badoiu@xxxxxxxxxxxxxxx>
> ---
>  lib/ukswrand/Config.uk   |   6 ++
>  lib/ukswrand/Makefile.uk |   3 +
>  lib/ukswrand/mwc_dev.c   | 119 +++++++++++++++++++++++++++++++++++++++
>  3 files changed, 128 insertions(+)
>  create mode 100644 lib/ukswrand/mwc_dev.c
> 
> diff --git a/lib/ukswrand/Config.uk b/lib/ukswrand/Config.uk
> index 44f6ee50..a1a84bc5 100644
> --- a/lib/ukswrand/Config.uk
> +++ b/lib/ukswrand/Config.uk
> @@ -17,4 +17,10 @@ endchoice
>  config LIBUKSWRAND_INITIALSEED
>       int "Initial random seed"
>       default 23
> +
> +config DEV_RANDOM
> +     bool "/dev/random device"
> +     select LIBDEVFS
> +     default n
> +
>  endif
> diff --git a/lib/ukswrand/Makefile.uk b/lib/ukswrand/Makefile.uk
> index 8d4482c4..25247474 100644
> --- a/lib/ukswrand/Makefile.uk
> +++ b/lib/ukswrand/Makefile.uk
> @@ -4,3 +4,6 @@ CINCLUDES-$(CONFIG_LIBUKSWRAND)       += 
> -I$(LIBUKSWRAND_BASE)/include
>  CXXINCLUDES-$(CONFIG_LIBUKSWRAND) += -I$(LIBUKSWRAND_BASE)/include
>  
>  LIBUKSWRAND_SRCS-$(CONFIG_LIBUKSWRAND_MWC) += $(LIBUKSWRAND_BASE)/mwc.c
> +ifdef CONFIG_DEV_RANDOM
> +LIBUKSWRAND_SRCS-$(CONFIG_LIBUKSWRAND_MWC) += $(LIBUKSWRAND_BASE)/mwc_dev.c
> +endif
> diff --git a/lib/ukswrand/mwc_dev.c b/lib/ukswrand/mwc_dev.c
> new file mode 100644
> index 00000000..5a9c0d49
> --- /dev/null
> +++ b/lib/ukswrand/mwc_dev.c
> @@ -0,0 +1,119 @@
> +/* SPDX-License-Identifier: BSD-3-Clause */
> +/*
> + * Authors: Vlad-Andrei Badoiu <vlad_andrei.badoiu@xxxxxxxxxxxxxxx>
> + *
> + * Copyright (c) 2019, University Politehnica of Bucharest. All rights 
> reserved.
> + *
> + * 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.
> + * 3. Neither the name of the copyright holder nor the names of its
> + *    contributors may be used to endorse or promote products derived from
> + *    this software without specific prior written permission.
> + *
> + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 COPYRIGHT HOLDER 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.
> + *
> + * THIS HEADER MAY NOT BE EXTRACTED OR MODIFIED IN ANY WAY.
> + */
> +
> +#include <stdlib.h>
> +#include <string.h>
> +#include <uk/ctors.h>
> +#include <uk/print.h>
> +#include <uk/swrand.h>
> +#include <uk/assert.h>
> +#include <uk/config.h>
> +#include <uk/essentials.h>
> +#include <vfscore/uio.h>
> +#include <devfs/device.h>
> +
> +#define DEV_RANDOM_NAME "random"
> +#define DEV_URANDOM_NAME "urandom"
> +
> +int dev_random_read(struct device *dev __unused, struct uio *uio,
> +                     int flags __unused)
> +{
> +     size_t count, step, chunk_size, i;
> +     char *buf;
> +     __u32 rd;
> +
> +     buf = uio->uio_iov->iov_base;
> +     count = uio->uio_iov->iov_len;
> +
> +     step = sizeof(__u32);
> +     chunk_size = count % step;
> +
> +     for (i = 0; i < count - chunk_size; i += step)
> +             *((__u32 *)buf + i) = uk_swrand_randr();
> +
> +     /* fill the remaining bytes of the buffer */
> +     if (chunk_size > 0) {
> +             rd = uk_swrand_randr();
> +             memcpy(buf + i, &rd, chunk_size);
> +     }
> +
> +     uio->uio_resid = 0;
> +     return 0;
> +}
> +
> +int dev_random_open(struct device *device __unused, int mode __unused)
> +{
> +     return 0;
> +}
> +
> +
> +int dev_random_close(struct device *device __unused)
> +{
> +     return 0;
> +}
> +
> +static struct devops random_devops = {
> +     .read = dev_random_read,
> +     .open = dev_random_open,
> +     .close = dev_random_close,
> +};
> +
> +static struct driver drv_random = {
> +     .devops = &random_devops,
> +     .devsz = 0,
> +     .name = DEV_RANDOM_NAME
> +};
> +
> +static struct driver drv_urandom = {
> +     .devops = &random_devops,
> +     .devsz = 0,
> +     .name = DEV_URANDOM_NAME
> +};
> +
> +__constructor_prio(102) static void _uk_dev_swrand_ctor(void)
> +{
> +     struct device *dev;
> +
> +     uk_pr_info("Add /dev/random and /dev/urandom\n");
> +
> +     /* register /dev/urandom */
> +     dev = device_create(&drv_urandom, DEV_URANDOM_NAME, D_CHR);
> +     if (dev == NULL)
> +             uk_pr_info("Failed to register /dev/urandom\n");
> +
> +     /* register /dev/random */
> +     dev = device_create(&drv_random, DEV_RANDOM_NAME, D_CHR);
> +     if (dev == NULL)
> +             uk_pr_info("Failed to register /dev/random\n");
> +}
> 

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