Add support to GEOM for GUID Partition Tables (GPTs). The support

is currently conditional on both the GEOM and GEOM_GPT options to
avoid getting GPT by default and having the MBR and GPT classes
clash.
The correct behaviour of the MBR class would be to back-off (reject)
a MBR if it's a Protective MBR (a MBR with a single partition of type
0xEE that spans the whole disk (as far as the MBR is concerned).
The correct behaviour if the GPT class would be to back-off (reject)
a GPT if there's a MBR that's not a Protective MBR.

At this stage it's inconvenient to destroy a good MBR when working
with GPTs that it's more convenient to have the MBR class back-off
when it detects the GPT signature on disk and have the GPT class
ignore the MBR.

In sys/gpt.h UUIDs (GUIDs) for the following FreeBSD partitions
have been defined:

GPT_ENT_TYPE_FREEBSD
	FreeBSD slice with disklabel. This is the equivalent of
	the well-known FreeBSD MBR partition type.
GPT_ENT_TYPE_FREEBSD_{SWAP|UFS|UFS2|VINUM}
	FreeBSD partitions in the context of disklabel. This is
	speculating on the idea to use the GPT to hold partitions
	instead if slices and removing the fixed (and low) limits
	we have on the number of partitions.

This commit lacks a GPT image for the regression suite.

1 files changed, 314 insertions, 0 deletions

diff --git a/sys/geom/geom_gpt.c b/sys/geom/geom_gpt.c
new file mode 100644
index 0000000..3f446e3
--- /dev/null
+++ b/sys/geom/geom_gpt.c
@@ -0,0 +1,314 @@
+/*-
+ * Copyright (c) 2002 Marcel Moolenaar
+ * Copyright (c) 2002 Poul-Henning Kamp
+ * Copyright (c) 2002 Networks Associates Technology, Inc.
+ * 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. The names of the authors may not be used to endorse or promote
+ *    products derived from this software without specific prior written
+ *    permission.
+ *
+ * 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.
+ *
+ * $FreeBSD$
+ */
+
+/*
+ * CRC32 code derived from work by Gary S. Brown.
+ */
+
+#include <sys/param.h>
+#ifndef _KERNEL
+#include <stdio.h>
+#include <string.h>
+#include <signal.h>
+#include <sys/param.h>
+#include <stdlib.h>
+#include <err.h>
+#else
+#include <sys/systm.h>
+#include <sys/kernel.h>
+#include <sys/malloc.h>
+#include <sys/bio.h>
+#include <sys/lock.h>
+#include <sys/mutex.h>
+#endif
+
+#include <sys/endian.h>
+#include <sys/errno.h>
+#include <sys/disklabel.h>
+#include <sys/sbuf.h>
+#include <sys/uuid.h>
+#include <sys/gpt.h>
+#include <geom/geom.h>
+#include <geom/geom_slice.h>
+
+/*
+ * XXX: GEOM is not dynamic enough. We are forced to use a compile-time
+ * limit. The minimum number of partitions (128) as required by EFI is
+ * most of the time just a waste of space.
+ */
+#define	GPT_MAX_SLICES	128
+
+struct g_gpt_softc {
+	struct gpt_ent *part[GPT_MAX_SLICES];
+};
+
+static uint32_t crc32_tab[] = {
+	0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419, 0x706af48f,
+	0xe963a535, 0x9e6495a3,	0x0edb8832, 0x79dcb8a4, 0xe0d5e91e, 0x97d2d988,
+	0x09b64c2b, 0x7eb17cbd, 0xe7b82d07, 0x90bf1d91, 0x1db71064, 0x6ab020f2,
+	0xf3b97148, 0x84be41de,	0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7,
+	0x136c9856, 0x646ba8c0, 0xfd62f97a, 0x8a65c9ec,	0x14015c4f, 0x63066cd9,
+	0xfa0f3d63, 0x8d080df5,	0x3b6e20c8, 0x4c69105e, 0xd56041e4, 0xa2677172,
+	0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b,	0x35b5a8fa, 0x42b2986c,
+	0xdbbbc9d6, 0xacbcf940,	0x32d86ce3, 0x45df5c75, 0xdcd60dcf, 0xabd13d59,
+	0x26d930ac, 0x51de003a, 0xc8d75180, 0xbfd06116, 0x21b4f4b5, 0x56b3c423,
+	0xcfba9599, 0xb8bda50f, 0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924,
+	0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d,	0x76dc4190, 0x01db7106,
+	0x98d220bc, 0xefd5102a, 0x71b18589, 0x06b6b51f, 0x9fbfe4a5, 0xe8b8d433,
+	0x7807c9a2, 0x0f00f934, 0x9609a88e, 0xe10e9818, 0x7f6a0dbb, 0x086d3d2d,
+	0x91646c97, 0xe6635c01, 0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e,
+	0x6c0695ed, 0x1b01a57b, 0x8208f4c1, 0xf50fc457, 0x65b0d9c6, 0x12b7e950,
+	0x8bbeb8ea, 0xfcb9887c, 0x62dd1ddf, 0x15da2d49, 0x8cd37cf3, 0xfbd44c65,
+	0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2, 0x4adfa541, 0x3dd895d7,
+	0xa4d1c46d, 0xd3d6f4fb, 0x4369e96a, 0x346ed9fc, 0xad678846, 0xda60b8d0,
+	0x44042d73, 0x33031de5, 0xaa0a4c5f, 0xdd0d7cc9, 0x5005713c, 0x270241aa,
+	0xbe0b1010, 0xc90c2086, 0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f,
+	0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4, 0x59b33d17, 0x2eb40d81,
+	0xb7bd5c3b, 0xc0ba6cad, 0xedb88320, 0x9abfb3b6, 0x03b6e20c, 0x74b1d29a,
+	0xead54739, 0x9dd277af, 0x04db2615, 0x73dc1683, 0xe3630b12, 0x94643b84,
+	0x0d6d6a3e, 0x7a6a5aa8, 0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1,
+	0xf00f9344, 0x8708a3d2, 0x1e01f268, 0x6906c2fe, 0xf762575d, 0x806567cb,
+	0x196c3671, 0x6e6b06e7, 0xfed41b76, 0x89d32be0, 0x10da7a5a, 0x67dd4acc,
+	0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5, 0xd6d6a3e8, 0xa1d1937e,
+	0x38d8c2c4, 0x4fdff252, 0xd1bb67f1, 0xa6bc5767, 0x3fb506dd, 0x48b2364b,
+	0xd80d2bda, 0xaf0a1b4c, 0x36034af6, 0x41047a60, 0xdf60efc3, 0xa867df55,
+	0x316e8eef, 0x4669be79, 0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236,
+	0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f, 0xc5ba3bbe, 0xb2bd0b28,
+	0x2bb45a92, 0x5cb36a04, 0xc2d7ffa7, 0xb5d0cf31, 0x2cd99e8b, 0x5bdeae1d,
+	0x9b64c2b0, 0xec63f226, 0x756aa39c, 0x026d930a, 0x9c0906a9, 0xeb0e363f,
+	0x72076785, 0x05005713, 0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38,
+	0x92d28e9b, 0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21, 0x86d3d2d4, 0xf1d4e242,
+	0x68ddb3f8, 0x1fda836e, 0x81be16cd, 0xf6b9265b, 0x6fb077e1, 0x18b74777,
+	0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c, 0x8f659eff, 0xf862ae69,
+	0x616bffd3, 0x166ccf45, 0xa00ae278, 0xd70dd2ee, 0x4e048354, 0x3903b3c2,
+	0xa7672661, 0xd06016f7, 0x4969474d, 0x3e6e77db, 0xaed16a4a, 0xd9d65adc,
+	0x40df0b66, 0x37d83bf0, 0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9,
+	0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6, 0xbad03605, 0xcdd70693,
+	0x54de5729, 0x23d967bf, 0xb3667a2e, 0xc4614ab8, 0x5d681b02, 0x2a6f2b94,
+	0xb40bbe37, 0xc30c8ea1, 0x5a05df1b, 0x2d02ef8d
+};
+
+static uint32_t
+crc32(const void *buf, size_t size)
+{
+	const uint8_t *p;
+	uint32_t crc;
+
+	p = buf;
+	crc = ~0U;
+
+	while (size--)
+		crc = crc32_tab[(crc ^ *p++) & 0xFF] ^ (crc >> 8);
+
+	return crc ^ ~0U;
+}
+
+static int
+is_gpt_hdr(struct gpt_hdr *hdr)
+{
+	uint32_t crc;
+
+	if (memcmp(hdr->hdr_sig, GPT_HDR_SIG, sizeof(hdr->hdr_sig)))
+		return (0);
+	crc = hdr->hdr_crc_self;
+	hdr->hdr_crc_self = 0;
+	if (crc32(hdr, hdr->hdr_size) != crc)
+		return (0);
+	hdr->hdr_crc_self = crc;
+	/* We're happy... */
+	return (1);
+}
+
+static int
+g_gpt_start(struct bio *bp)
+{
+	struct uuid freebsd = GPT_ENT_TYPE_FREEBSD;
+	struct g_provider *pp = bp->bio_to;
+	struct g_geom *gp = pp->geom;
+	struct g_slicer *gsp = gp->softc;
+	struct g_gpt_softc *gs = gsp->softc;
+	u_int type;
+
+	if (bp->bio_cmd != BIO_GETATTR)
+		return (0);
+
+	/*
+	 * XXX: this is bogus. The BSD class has a strong dependency on
+	 * the MBR/MBREXT class, because it asks for an attribute that's
+	 * specific to the MBR/MBREXT class and the value of the attribute
+	 * is just as specific to the MBR class. In an extensible scheme
+	 * a geom would ask another geom if it could possible accomodate a
+	 * class and the answer should be yes or no. Now we're forced to
+	 * emulate a MBR class :-/
+	 */
+	type = (memcmp(&gs->part[pp->index]->ent_type, &freebsd,
+	    sizeof(freebsd))) ? 0 : 165;
+	return ((g_haveattr_int(bp, "MBR::type", type)) ? 1 : 0);
+}
+
+static void
+g_gpt_dumpconf(struct sbuf *sb, char *indent, struct g_geom *gp,
+    struct g_consumer *cp, struct g_provider *pp)
+{
+	struct g_slicer *gsp = gp->softc;
+	struct g_gpt_softc *gs = gsp->softc;
+	struct uuid *uuid;
+
+	g_slice_dumpconf(sb, indent, gp, cp, pp);
+
+	if (pp != NULL) {
+		uuid = &gs->part[pp->index]->ent_type;
+		sbuf_printf(sb, "%s<type>", indent);
+		sbuf_printf_uuid(sb, uuid);
+		sbuf_printf(sb, "</type>\n");
+	}
+}
+
+static struct g_geom *
+g_gpt_taste(struct g_class *mp, struct g_provider *pp, int insist)
+{
+	struct g_consumer *cp;
+	struct g_geom *gp;
+	struct g_gpt_softc *gs;
+	struct g_slicer *gsp;
+	u_char *buf, *mbr;
+	struct gpt_ent *ent;
+	struct gpt_hdr *hdr;
+	u_int i, npart, secsz, tblsz;
+	int error;
+
+	g_trace(G_T_TOPOLOGY, "g_gpt_taste(%s,%s)", mp->name, pp->name);
+	g_topology_assert();
+
+	/*
+	 * XXX: I don't like to hardcode a maximum number of slices, since
+	 * it's wasting space most of the time and insufficient any time.
+	 * It's easier for now...
+	 */
+	gp = g_slice_new(mp, GPT_MAX_SLICES, pp, &cp, &gs, sizeof(*gs),
+	    g_gpt_start);
+	if (gp == NULL)
+		return (NULL);
+
+	gsp = gp->softc;
+	g_topology_unlock();
+	gp->dumpconf = g_gpt_dumpconf;
+
+	npart = 0;
+	mbr = NULL;
+
+	if (gp->rank != 2 && insist == 0)
+		goto out;
+
+	error = g_getattr("GEOM::sectorsize", cp, &secsz);
+	if (error)
+		goto out;
+
+	/* XXX: we need to get the media size as well. */
+
+	/* Read both the MBR sector and the GPT sector. */
+	mbr = g_read_data(cp, 0, 2 * secsz, &error);
+	if (mbr == NULL || error != 0)
+		goto out;
+#if 0
+	/*
+	 * XXX: we should ignore the GPT if there's a MBR and the MBR is
+	 * not a PMBR (Protective MBR). I believe this is what the EFI
+	 * spec is going to say eventually (this is hearsay :-)
+	 * Currently EFI (version 1.02) accepts and uses the GPT even
+	 * though there's a valid MBR. We do this too, because it allows
+	 * us to test this code without first nuking the only partitioning
+	 * scheme we grok until this is working.
+	 */
+	if (!is_pmbr((void*)mbr))
+		goto out;
+#endif
+
+	hdr = (void*)(mbr + secsz);
+
+	/*
+	 * XXX: if we don't have a GPT header at LBA 1, we should check if
+	 * there's a backup GPT at the end of the medium. If we have a valid
+	 * backup GPT, we should restore the primary GPT and claim this lunch.
+	 */
+	if (!is_gpt_hdr(hdr))
+		goto out;
+
+	tblsz = (hdr->hdr_entries * hdr->hdr_entsz + secsz - 1) & ~(secsz - 1);
+	buf = g_read_data(cp, hdr->hdr_lba_table * secsz, tblsz, &error);
+
+	gsp->frontstuff = hdr->hdr_lba_start * secsz;
+
+	for (i = 0; i < hdr->hdr_entries; i++) {
+		struct uuid unused = GPT_ENT_TYPE_UNUSED;
+		if (i >= GPT_MAX_SLICES)
+			break;
+		ent = (void*)(buf + i * hdr->hdr_entsz);
+		if (!memcmp(&ent->ent_type, &unused, sizeof(unused)))
+			continue;
+		gs->part[i] = g_malloc(hdr->hdr_entsz, M_WAITOK);
+		if (gs->part[i] == NULL)
+			break;
+		bcopy(ent, gs->part[i], hdr->hdr_entsz);
+		(void)g_slice_addslice(gp, i, ent->ent_lba_start * secsz,
+		    (ent->ent_lba_end - ent->ent_lba_start + 1ULL) * secsz,
+		    "%ss%d", gp->name, i + 1);
+		npart++;
+	}
+
+	g_free(buf);
+
+ out:
+	if (mbr != NULL)
+		g_free(mbr);
+
+	g_topology_lock();
+	error = g_access_rel(cp, -1, 0, 0);
+
+	if (npart > 0) {
+		LIST_FOREACH(pp, &gp->provider, provider)
+			g_error_provider(pp, 0);
+		return (gp);
+	}
+	g_std_spoiled(cp);
+	return (NULL);
+}
+
+static struct g_class g_gpt_class = {
+	"GPT",
+	g_gpt_taste,
+	NULL,
+	G_CLASS_INITSTUFF
+};
+
+DECLARE_GEOM_CLASS(g_gpt_class, g_gpt);