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Re: [Minios-devel] [UNIKRAFT PATCH v3 1/1] lib/ukswrand: Add /dev/random and /dev/urandom
Hey,
while you work on a patch that applies to upstream, I still have some
comments about this patch.
On 15.06.19 09:03, Costin Lupu wrote:
Actually the v2 was already pushed upstream. The new changes should be
in a different patch.
On 6/15/19 3:55 AM, 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>
Reviewed-by: Costin Lupu <costin.lupu@xxxxxxxxx>
---
lib/ukswrand/Config.uk | 8 +++
lib/ukswrand/Makefile.uk | 3 +
lib/ukswrand/mwc_dev.c | 120 +++++++++++++++++++++++++++++++++++++++
3 files changed, 131 insertions(+)
create mode 100644 lib/ukswrand/mwc_dev.c
diff --git a/lib/ukswrand/Config.uk b/lib/ukswrand/Config.uk
index 44f6ee50..5b0adb85 100644
--- a/lib/ukswrand/Config.uk
+++ b/lib/ukswrand/Config.uk
@@ -17,4 +17,12 @@ endchoice
config LIBUKSWRAND_INITIALSEED
int "Initial random seed"
default 23
+
+config LIBUKSWRAND_DEV_RANDOM
+ bool "random and urandom devices"
+ select LIBDEVFS
+ default n
+ help
+ Registers the random and urandom devices
Please mention that this registers to libdevfs.
+
endif
diff --git a/lib/ukswrand/Makefile.uk b/lib/ukswrand/Makefile.uk
index 8d4482c4..8c6b3637 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) += $(LIBUKSWRAND_BASE)/mwc.c
+ifdef CONFIG_LIBUKSWRAND_DEV_RANDOM
+LIBUKSWRAND_SRCS-$(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..09a9c817
--- /dev/null
+++ b/lib/ukswrand/mwc_dev.c
@@ -0,0 +1,120 @@
+/* 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;
+}
You should add a "/* TODO */" comment that mentions that this function
is not thread-safe nor SMP-safe since uk_swrand_randr() isn't either.
+
+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("Register %s and %s\n",
+ DEV_RANDOM_NAME, DEV_URANDOM_NAME);
I would still prefer a bit more verbose message:
"Register '%s' and '%s' to devfs\n"
+
+ /* register /dev/urandom */
+ dev = device_create(&drv_urandom, DEV_URANDOM_NAME, D_CHR);
+ if (dev == NULL)
+ uk_pr_err("Failed to register %s\n", DEV_URANDOM_NAME);
+
+ /* register /dev/random */
+ dev = device_create(&drv_random, DEV_RANDOM_NAME, D_CHR);
+ if (dev == NULL)
+ uk_pr_err("fAiled to register %s\n", DEV_RANDOM_NAME);
You have a typo here. ;-) I also still prefer that you mention that the
operation failed to register to devfs with both messages:
uk_pr_err("Failed to register '%s' to devfs\n", [...]);
+}
Thanks a lot,
Simon
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