lindev(4) [1] is supposed to be a collection of linux-specific pseudo

devices that we also support, just not by default (thus only LINT or
module builds by default).

While currently there is only "/dev/full" [2], we are planning to see more
in the future.  We may decide to change the module/dependency logic in the
future should the list grow too long.

This is not part of linux.ko as also non-linux binaries like kFreeBSD
userland or ports can make use of this as well.

Suggested by:	rwatson [1] (name)
Submitted by:	ed [2]
Discussed with:	markm, ed, rwatson, kib (weeks ago)
Reviewed by:	rwatson, brueffer (prev. version)
PR:		kern/68961
MFC after:	6 weeks

3 files changed, 210 insertions, 0 deletions

diff --git a/sys/dev/lindev/full.c b/sys/dev/lindev/full.c
new file mode 100644
index 0000000..294094c
--- /dev/null
+++ b/sys/dev/lindev/full.c
@@ -0,0 +1,103 @@
+/*-
+ * Copyright (c) 2009 Ed Schouten <ed@FreeBSD.org>
+ * 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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/param.h>
+#include <sys/conf.h>
+#include <sys/kernel.h>
+#include <sys/malloc.h>
+#include <sys/module.h>
+#include <sys/systm.h>
+#include <sys/uio.h>
+
+#include <dev/lindev/lindev.h>
+
+static struct cdev *full_dev;
+
+static d_read_t full_read;
+static d_write_t full_write;
+
+static struct cdevsw full_cdevsw = {
+	.d_version =	D_VERSION,
+	.d_read =	full_read,
+	.d_write =	full_write,
+	.d_name =	"full",
+};
+
+static void *zbuf;
+
+/* ARGSUSED */
+static int
+full_read(struct cdev *dev __unused, struct uio *uio, int flags __unused)
+{
+	int error = 0;
+
+	while (uio->uio_resid > 0 && error == 0)
+		error = uiomove(zbuf, MIN(uio->uio_resid, PAGE_SIZE), uio);
+
+	return (error);
+}
+
+/* ARGSUSED */
+static int
+full_write(struct cdev *dev __unused, struct uio *uio __unused,
+    int flags __unused)
+{
+
+	return (ENOSPC);
+}
+
+/* ARGSUSED */
+int
+lindev_modevent_full(module_t mod __unused, int type, void *data __unused)
+{
+
+	switch(type) {
+	case MOD_LOAD:
+		zbuf = (void *)malloc(PAGE_SIZE, M_TEMP, M_WAITOK | M_ZERO);
+		full_dev = make_dev(&full_cdevsw, 0, UID_ROOT, GID_WHEEL,
+		    0666, "full");
+		if (bootverbose)
+			printf("full: <full device>\n");
+		break;
+
+	case MOD_UNLOAD:
+		destroy_dev(full_dev);
+		free(zbuf, M_TEMP);
+		break;
+
+	case MOD_SHUTDOWN:
+		break;
+
+	default:
+		return (EOPNOTSUPP);
+	}
+
+	return (0);
+}
+
diff --git a/sys/dev/lindev/lindev.c b/sys/dev/lindev/lindev.c
new file mode 100644
index 0000000..cf87604
--- /dev/null
+++ b/sys/dev/lindev/lindev.c
@@ -0,0 +1,73 @@
+/*-
+ * Copyright (c) 2009 "Bjoern A. Zeeb" <bz@FreeBSD.org>
+ * 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
+ */
+
+/*
+ * "lindev" is supposed to be a collection of linux-specific devices
+ * that we also support, just not by default.
+ * While currently there is only "/dev/full", we are planning to see
+ * more in the future.
+ * This file is only the container to load/unload all supported devices;
+ * the implementation of each should go into its own file.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <sys/param.h>
+#include <sys/conf.h>
+#include <sys/kernel.h>
+#include <sys/module.h>
+
+#include <dev/lindev/lindev.h>
+
+/* ARGSUSED */
+static int
+lindev_modevent(module_t mod, int type, void *data)
+{
+	int error;
+
+	switch(type) {
+	case MOD_LOAD:
+		error = lindev_modevent_full(mod, type, data);
+		break;
+
+	case MOD_UNLOAD:
+		error = lindev_modevent_full(mod, type, data);
+		break;
+
+	case MOD_SHUTDOWN:
+		error = lindev_modevent_full(mod, type, data);
+		break;
+
+	default:
+		return (EOPNOTSUPP);
+	}
+
+	return (error);
+}
+
+DEV_MODULE(lindev, lindev_modevent, NULL);
+MODULE_VERSION(lindev, 1);
diff --git a/sys/dev/lindev/lindev.h b/sys/dev/lindev/lindev.h
new file mode 100644
index 0000000..9b0be82
--- /dev/null
+++ b/sys/dev/lindev/lindev.h
@@ -0,0 +1,34 @@
+/*-
+ * Copyright (c) 2009 "Bjoern A. Zeeb" <bz@FreeBSD.org>
+ * 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
+ *
+ * $FreeBSD$
+ */
+
+#ifndef	_DEV_LINDEV_LINDEV_H
+#define	_DEV_LINDEV_LINDEV_H
+
+int lindev_modevent_full(module_t, int, void *);
+
+#endif /* _DEV_LINDEV_LINDEV_H */