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Re: [Minios-devel] [UNIKRAFT PATCH v3 2/3] lib/devfs: Add /dev/null and /dev/zero support
Thanks for the update! See my comment inline.
On 14.02.20 16:41, stefanl.teodorescu@xxxxxxxxx wrote:
From: Costin Lupu <costin.lupu@xxxxxxxxx>
This is shamelessly copied and adapted from our implementation
for /dev/random device support.
Signed-off-by: Costin Lupu <costin.lupu@xxxxxxxxx>
Signed-off-by: Stefan Teodorescu <stefanl.teodorescu@xxxxxxxxx>
---
lib/devfs/Config.uk | 17 ++++
lib/devfs/Makefile.uk | 1 +
lib/devfs/null.c | 145 ++++++++++++++++++++++++++++++
lib/vfscore/include/vfscore/uio.h | 1 +
4 files changed, 164 insertions(+)
create mode 100644 lib/devfs/null.c
diff --git a/lib/devfs/Config.uk b/lib/devfs/Config.uk
index 6f21c01c..af61747f 100644
--- a/lib/devfs/Config.uk
+++ b/lib/devfs/Config.uk
@@ -8,4 +8,21 @@ if LIBDEVFS
bool "Mount /dev during boot"
depends on LIBVFSCORE_AUTOMOUNT_ROOTFS
default n
+
+ # hidden
+ config LIBDEVFS_DEV_NULL_ZERO
+ bool
+ default n
+
+ config LIBDEVFS_DEV_NULL
+ bool "Register null device"
+ default y if LIBDEVFS_AUTOMOUNT
+ select LIBDEVFS_DEV_NULL_ZERO
+ default n
+
+ config LIBDEVFS_DEV_ZERO
+ bool "Register zero device"
+ default y if LIBDEVFS_AUTOMOUNT
+ select LIBDEVFS_DEV_NULL_ZERO
+ default n
endif
diff --git a/lib/devfs/Makefile.uk b/lib/devfs/Makefile.uk
index c496fd56..b23ebf15 100644
--- a/lib/devfs/Makefile.uk
+++ b/lib/devfs/Makefile.uk
@@ -6,3 +6,4 @@ LIBDEVFS_CFLAGS-$(call gcc_version_ge,8,0) +=
-Wno-cast-function-type
LIBDEVFS_SRCS-y += $(LIBDEVFS_BASE)/device.c
LIBDEVFS_SRCS-y += $(LIBDEVFS_BASE)/devfs_vnops.c
+LIBDEVFS_SRCS-$(CONFIG_LIBDEVFS_DEV_NULL_ZERO) += $(LIBDEVFS_BASE)/null.c
diff --git a/lib/devfs/null.c b/lib/devfs/null.c
new file mode 100644
index 00000000..60ada995
--- /dev/null
+++ b/lib/devfs/null.c
@@ -0,0 +1,145 @@
+/* SPDX-License-Identifier: BSD-3-Clause */
+/*
+ * Authors: Costin Lupu <costin.lupu@xxxxxxxxx>
+ *
+ * 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.
I know that you probably copied this license header from another file
but we noticed that this sentence is probably in conflict with the
license ahead. Can this be removed? With your okay, I would do it for
you while upstreaming.
+ */
+
+#include <uk/config.h>
+#include <stdlib.h>
+#include <string.h>
+#include <uk/ctors.h>
+#include <uk/print.h>
+#include <vfscore/uio.h>
+#include <devfs/device.h>
+
+
+int dev_null_write(struct device *dev __unused, struct uio *uio, int flags
__unused)
+{
+ uio->uio_resid = 0;
+ return 0;
+}
+
+int dev_null_open(struct device *device __unused, int mode __unused)
+{
+ return 0;
+}
+
+
+int dev_null_close(struct device *device __unused)
+{
+ return 0;
+}
+
+#ifdef CONFIG_LIBDEVFS_DEV_NULL
+
+#define DEV_NULL_NAME "null"
+
+int dev_null_read(struct device *dev __unused, struct uio *uio, int flags
__unused)
+{
+ uio->uio_resid = uio->uio_iov->iov_len;
+ return 0;
+}
+
+static struct devops null_devops = {
+ .read = dev_null_read,
+ .write = dev_null_write,
+ .open = dev_null_open,
+ .close = dev_null_close,
+};
+
+static struct driver drv_null = {
+ .devops = &null_devops,
+ .devsz = 0,
+ .name = DEV_NULL_NAME
+};
+#endif
+
+#ifdef CONFIG_LIBDEVFS_DEV_ZERO
+
+#define DEV_ZERO_NAME "zero"
+
+int dev_zero_read(struct device *dev __unused, struct uio *uio, int flags
__unused)
+{
+ size_t count;
+ char *buf;
+
+ buf = uio->uio_iov->iov_base;
+ count = uio->uio_iov->iov_len;
+
+ memset(buf, 0, count);
+ uio->uio_resid = 0;
+ return 0;
+}
+
+static struct devops zero_devops = {
+ .read = dev_zero_read,
+ .write = dev_null_write,
+ .open = dev_null_open,
+ .close = dev_null_close,
+};
+
+static struct driver drv_zero = {
+ .devops = &zero_devops,
+ .devsz = 0,
+ .name = DEV_ZERO_NAME
+};
+#endif
+
+static int devfs_register_null(void)
+{
+ struct device *dev;
+
+#ifdef CONFIG_LIBDEVFS_DEV_NULL
+ uk_pr_debug("Register '%s' to devfs\n", DEV_NULL_NAME);
+
+ /* register /dev/null */
+ dev = device_create(&drv_null, DEV_NULL_NAME, D_CHR);
+ if (dev == NULL) {
+ uk_pr_err("Failed to register '%s' to devfs\n", DEV_NULL_NAME);
+ return -1;
+ }
+#endif
+
+#ifdef CONFIG_LIBDEVFS_DEV_ZERO
+ uk_pr_debug("Register '%s' to devfs\n", DEV_ZERO_NAME);
+
+ /* register /dev/zero */
+ dev = device_create(&drv_zero, DEV_ZERO_NAME, D_CHR);
+ if (dev == NULL) {
+ uk_pr_err("Failed to register '%s' to devfs\n", DEV_ZERO_NAME);
+ return -1;
+ }
+#endif
+
+ return 0;
+}
+
+devfs_initcall(devfs_register_null);
diff --git a/lib/vfscore/include/vfscore/uio.h
b/lib/vfscore/include/vfscore/uio.h
index 83dd5b9a..b14fdb82 100644
--- a/lib/vfscore/include/vfscore/uio.h
+++ b/lib/vfscore/include/vfscore/uio.h
@@ -36,6 +36,7 @@
#include <sys/types.h>
#include <sys/uio.h>
#include <limits.h>
+#include <uk/assert.h>
enum uio_rw { UIO_READ, UIO_WRITE };
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