Add uuidgen(2) and uuidgen(1).

The uuidgen command, by means of the uuidgen syscall, generates one
or more Universally Unique Identifiers compatible with OSF/DCE 1.1
version 1 UUIDs.

From the Perforce logs (change 11995):

Round of cleanups:
o  Give uuidgen() the correct prototype in syscalls.master
o  Define struct uuid according to DCE 1.1 in sys/uuid.h
o  Use struct uuid instead of uuid_t. The latter is defined
   in sys/uuid.h but should not be used in kernel land.
o  Add snprintf_uuid(), printf_uuid() and sbuf_printf_uuid()
   to kern_uuid.c for use in the kernel (currently geom_gpt.c).
o  Rename the non-standard struct uuid in kern/kern_uuid.c
   to struct uuid_private and give it a slightly better definition
   for better byte-order handling. See below.
o  In sys/gpt.h, fix the broken uuid definitions to match the now
   compliant struct uuid definition. See below.
o  In usr.bin/uuidgen/uuidgen.c catch up with struct uuid change.

A note about byte-order:
        The standard failed to provide a non-conflicting and
unambiguous definition for the binary representation. My initial
implementation always wrote the timestamp as a 64-bit little-endian
(2s-complement) integral. The clock sequence was always written
as a 16-bit big-endian (2s-complement) integral. After a good
nights sleep and couple of Pan Galactic Gargle Blasters (not
necessarily in that order :-) I reread the spec and came to the
conclusion that the time fields are always written in the native
by order, provided the the low, mid and hi chopping still occurs.
The spec mentions that you "might need to swap bytes if you talk
to a machine that has a different byte-order". The clock sequence
is always written in big-endian order (as is the IEEE 802 address)
because its division is resulting in bytes, making the ordering
unambiguous.

1 files changed, 222 insertions, 0 deletions

diff --git a/sys/kern/kern_uuid.c b/sys/kern/kern_uuid.c
new file mode 100644
index 000000000000..ba5faa51a2b6
--- /dev/null
+++ b/sys/kern/kern_uuid.c
@@ -0,0 +1,222 @@
+/*
+ * Copyright (c) 2002 Marcel Moolenaar
+ * 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 ``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 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.
+ *
+ * $FreeBSD$
+ */
+
+#include <sys/param.h>
+#include <sys/endian.h>
+#include <sys/kernel.h>
+#include <sys/lock.h>
+#include <sys/mutex.h>
+#include <sys/sbuf.h>
+#include <sys/socket.h>
+#include <sys/sysproto.h>
+#include <sys/uuid.h>
+
+#include <net/if.h>
+#include <net/if_dl.h>
+#include <net/if_types.h>
+
+/*
+ * See also:
+ *	http://www.opengroup.org/dce/info/draft-leach-uuids-guids-01.txt
+ *	http://www.opengroup.org/onlinepubs/009629399/apdxa.htm
+ *
+ * Note that the generator state is itself an UUID, but the time and clock
+ * sequence fields are written in the native byte order.
+ */
+
+CTASSERT(sizeof(struct uuid) == 16);
+
+/* We use an alternative, more convenient representation in the generator. */
+struct uuid_private {
+	union {
+		uint64_t	ll;		/* internal. */
+		struct {
+			uint32_t	low;
+			uint16_t	mid;
+			uint16_t	hi;
+		} x;
+	} time;
+	uint16_t	seq;			/* Big-endian. */
+	uint16_t	node[UUID_NODE_LEN>>1];
+};
+
+CTASSERT(sizeof(struct uuid_private) == 16);
+
+static struct uuid_private uuid_last;
+
+static struct mtx uuid_mutex;
+MTX_SYSINIT(uuid_lock, &uuid_mutex, "UUID generator mutex lock", MTX_DEF);
+
+/*
+ * Return the first MAC address we encounter or, if none was found,
+ * construct a sufficiently random multicast address. We don't try
+ * to return the same MAC address as previously returned. We always
+ * generate a new multicast address if no MAC address exists in the
+ * system.
+ * It would be nice to know if 'ifnet' or any of its sub-structures
+ * has been changed in any way. If not, we could simply skip the
+ * scan and safely return the MAC address we returned before.
+ */
+static void
+uuid_node(uint16_t *node)
+{
+	struct ifnet *ifp;
+	struct ifaddr *ifa;
+	struct sockaddr_dl *sdl;
+	int i;
+
+	/* XXX: lock ifnet. */
+	TAILQ_FOREACH(ifp, &ifnet, if_link) {
+		/* Walk the address list */
+		TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
+			sdl = (struct sockaddr_dl*)ifa->ifa_addr;
+			if (sdl != NULL && sdl->sdl_family == AF_LINK &&
+			    sdl->sdl_type == IFT_ETHER) {
+				/* Got a MAC address. */
+				bcopy(LLADDR(sdl), node, UUID_NODE_LEN);
+				/* XXX: unlock ifnet. */
+				return;
+			}
+		}
+	}
+	/* XXX: unlock ifnet. */
+
+	for (i = 0; i < (UUID_NODE_LEN>>1); i++)
+		node[i] = (uint16_t)arc4random();
+	*((uint8_t*)node) |= 0x80;
+}
+
+/*
+ * Get the current time as a 60 bit count of 100-nanosecond intervals
+ * since 00:00:00.00, October 15,1582. We apply a magic offset to convert
+ * the Unix time since 00:00:00.00, Januari 1, 1970 to the date of the
+ * Gregorian reform to the Christian calendar.
+ */
+static uint64_t
+uuid_time(void)
+{
+	struct bintime bt;
+	uint64_t time = 0x01B21DD213814000LL;
+
+	bintime(&bt);
+	time += (uint64_t)bt.sec * 10000000LL;
+	time += (10000000LL * (uint32_t)(bt.frac >> 32)) >> 32;
+	return (time & ((1LL << 60) - 1LL));
+}
+
+#ifndef _SYS_SYSPROTO_H_
+struct uuidgen_args {
+	struct uuid *store;
+	int	count;
+};
+#endif
+
+int uuidgen(struct thread *td, struct uuidgen_args *uap)
+{
+	struct uuid_private uuid;
+	uint64_t time;
+	int error;
+
+	/*
+	 * Limit the number of UUIDs that can be created at the same time
+	 * to some arbitrary number. This isn't really necessary, but I
+	 * like to have some sort of upper-bound that's less than 2G :-)
+	 * XXX needs to be tunable.
+	 */
+	if (uap->count < 1 || uap->count > 2048)
+		return (EINVAL);
+
+	/* XXX: pre-validate accessibility to the whole of the UUID store? */
+
+	mtx_lock(&uuid_mutex);
+
+	uuid_node(uuid.node);
+	time = uuid_time();
+
+	if (uuid_last.time.ll == 0LL || uuid_last.node[0] != uuid.node[0] ||
+	    uuid_last.node[1] != uuid.node[1] ||
+	    uuid_last.node[2] != uuid.node[2])
+		uuid.seq = (uint16_t)arc4random() & 0x3fff;
+	else if (uuid_last.time.ll >= time)
+		uuid.seq = (uuid_last.seq + 1) & 0x3fff;
+	else
+		uuid.seq = uuid_last.seq;
+
+	uuid_last = uuid;
+	uuid_last.time.ll = (time + uap->count - 1) & ((1LL << 60) - 1LL);
+
+	mtx_unlock(&uuid_mutex);
+
+	/* Set sequence and variant and deal with byte order. */
+	uuid.seq = htobe16(uuid.seq | 0x8000);
+
+	/* XXX: this should copyout larger chunks at a time. */
+	do {
+		/* Set time and version (=1) and deal with byte order. */
+		uuid.time.x.low = (uint32_t)time;
+		uuid.time.x.mid = (uint16_t)(time >> 32);
+		uuid.time.x.hi = ((uint16_t)(time >> 48) & 0xfff) | (1 << 12);
+		error = copyout(&uuid, uap->store, sizeof(uuid));
+		uap->store++;
+		uap->count--;
+		time++;
+	} while (uap->count > 0 && !error);
+
+	return (error);
+}
+
+int
+snprintf_uuid(char *buf, size_t sz, struct uuid *uuid)
+{
+	struct uuid_private *id;
+	int cnt;
+
+	id = (struct uuid_private *)uuid;
+	cnt = snprintf(buf, sz, "%08x-%04x-%04x-%04x-%04x%04x%04x",
+	    id->time.x.low, id->time.x.mid, id->time.x.hi, be16toh(id->seq),
+	    be16toh(id->node[0]), be16toh(id->node[1]), be16toh(id->node[2]));
+	return (cnt);
+}
+
+int
+printf_uuid(struct uuid *uuid)
+{
+	char buf[38];
+
+	snprintf_uuid(buf, sizeof(buf), uuid);
+	return (printf("%s", buf));
+}
+
+int
+sbuf_printf_uuid(struct sbuf *sb, struct uuid *uuid)
+{
+	char buf[38];
+
+	snprintf_uuid(buf, sizeof(buf), uuid);
+	return (sbuf_printf(sb, "%s", buf));
+}