Add the show command to print the partition information ala gpt(8).

Update the manpage accordingly. While here, mention the MBR scheme
and add a bugs section. With this commit gpt(8) can be obsoleted.

sbin/geom/class/part/geom_part.c

@@ -31,8 +31,8 @@ __FBSDID("$FreeBSD$");
 #include <stdint.h>
 #include <stdlib.h>
 #include <unistd.h>
+#include <err.h>
 #include <fcntl.h>
-#include <readpassphrase.h>
 #include <string.h>
 #include <strings.h>
 #include <libgeom.h>
@@ -49,6 +49,8 @@ uint32_t version = 0;
 static char optional[] = "";
 static char flags[] = "C";
 
+static void gpart_show(struct gctl_req *, unsigned);
+
 struct g_command class_commands[] = {
 	{ "add", 0, NULL, {
 		{ 'b', "start", NULL, G_TYPE_STRING },
@@ -86,6 +88,186 @@ struct g_command class_commands[] = {
 		G_OPT_SENTINEL },
 	  "geom", NULL
 	},
+	{ "show", 0, gpart_show, G_NULL_OPTS, "[geom ...]", NULL },
 	{ "undo", 0, NULL, G_NULL_OPTS, "geom", NULL },
 	G_CMD_SENTINEL
 };
+
+static struct gclass *
+find_class(struct gmesh *mesh, const char *name)
+{
+	struct gclass *classp;
+
+	LIST_FOREACH(classp, &mesh->lg_class, lg_class) {
+		if (strcmp(classp->lg_name, name) == 0)
+			return (classp);
+	}
+	return (NULL);
+}
+
+static struct ggeom *
+find_geom(struct gclass *classp, const char *name)
+{
+	struct ggeom *gp;
+
+	LIST_FOREACH(gp, &classp->lg_geom, lg_geom) {
+		if (strcmp(gp->lg_name, name) == 0)
+			return (gp);
+	}
+	return (NULL);
+}
+
+static const char *
+find_geomcfg(struct ggeom *gp, const char *cfg)
+{
+	struct gconfig *gc;
+
+	LIST_FOREACH(gc, &gp->lg_config, lg_config) {
+		if (!strcmp(gc->lg_name, cfg))
+			return (gc->lg_val);
+	}
+	return (NULL);
+}
+
+static const char *
+find_provcfg(struct gprovider *pp, const char *cfg)
+{
+	struct gconfig *gc;
+
+	LIST_FOREACH(gc, &pp->lg_config, lg_config) {
+		if (!strcmp(gc->lg_name, cfg))
+			return (gc->lg_val);
+	}
+	return (NULL);
+}
+
+static struct gprovider *
+find_provider(struct ggeom *gp, unsigned long long minsector)
+{
+	struct gprovider *pp, *bestpp;
+	unsigned long long offset;
+	unsigned long long sector, bestsector;
+
+	bestpp = NULL;
+	LIST_FOREACH(pp, &gp->lg_provider, lg_provider) {
+		offset = atoll(find_provcfg(pp, "offset"));
+		sector = offset / pp->lg_sectorsize;
+		if (sector < minsector)
+			continue;
+		if (bestpp != NULL && sector >= bestsector)
+			continue;
+		bestpp = pp;
+		bestsector = sector;
+	}
+	return (bestpp);
+}
+
+static const char *
+fmtsize(long double rawsz)
+{
+	static char buf[32];
+	static const char *sfx[] = { "B", "KB", "MB", "GB", "TB" };
+	long double sz;
+	int sfxidx;
+
+	sfxidx = 0;
+	sz = (long double)rawsz;
+	while (sfxidx < 4 && sz > 1099.0) {
+		sz /= 1000;
+		sfxidx++;
+	}
+
+	sprintf(buf, "%.1Lf%s", sz, sfx[sfxidx]);
+	return (buf);
+}
+
+static void
+gpart_show_geom(struct ggeom *gp)
+{
+	struct gprovider *pp;
+	const char *s, *scheme;
+	unsigned long long first, last, sector, end;
+	unsigned long long offset, length, secsz;
+	int idx, wblocks, wname;
+
+	scheme = find_geomcfg(gp, "scheme");
+	s = find_geomcfg(gp, "first");
+	first = atoll(s);
+	s = find_geomcfg(gp, "last");
+	last = atoll(s);
+	wblocks = strlen(s);
+	wname = strlen(gp->lg_name);
+	pp = LIST_FIRST(&gp->lg_consumer)->lg_provider;
+	secsz = pp->lg_sectorsize;
+	printf("=>%*llu  %*llu  %*s  %s  (%s)\n",
+	    wblocks, first, wblocks, (last - first + 1),
+	    wname, gp->lg_name,
+	    scheme, fmtsize(pp->lg_mediasize));
+
+	while ((pp = find_provider(gp, first)) != NULL) {
+		s = find_provcfg(pp, "offset");
+		offset = atoll(s);
+		sector = offset / secsz;
+		s = find_provcfg(pp, "length");
+		length = atoll(s);
+		s = find_provcfg(pp, "index");
+		idx = atoi(s);
+		end = sector + length / secsz;
+		if (first < sector) {
+			printf("  %*llu  %*llu  %*s  - free -  (%s)\n",
+			    wblocks, first, wblocks, sector - first,
+			    wname, "",
+			    fmtsize((sector - first) * secsz));
+		}
+		printf("  %*llu  %*llu  %*d  %s  (%s)\n",
+		    wblocks, sector, wblocks, end - sector,
+		    wname, idx,
+		    find_provcfg(pp, "type"), fmtsize(pp->lg_mediasize));
+		first = end;
+	}
+	if (first <= last) {
+		printf("  %*llu  %*llu  %*s  - free -  (%s)\n",
+		    wblocks, first, wblocks, last - first + 1,
+		    wname, "",
+		    fmtsize((last - first + 1) * secsz));
+	}
+	printf("\n");
+}
+
+static void
+gpart_show(struct gctl_req *req, unsigned fl __unused)
+{
+	struct gmesh mesh;
+	struct gclass *classp;
+	struct ggeom *gp;
+	const char *name;
+	int error, i, nargs;
+
+	name = gctl_get_ascii(req, "class");
+	if (name == NULL)
+		abort();
+	error = geom_gettree(&mesh);
+	if (error != 0)
+		errc(EXIT_FAILURE, error, "Cannot get GEOM tree");
+	classp = find_class(&mesh, name);
+	if (classp == NULL) {
+		geom_deletetree(&mesh);
+		errx(EXIT_FAILURE, "Class %s not found.", name);
+	}
+	nargs = gctl_get_int(req, "nargs");
+	if (nargs > 0) {
+		for (i = 0; i < nargs; i++) {
+			name = gctl_get_ascii(req, "arg%d", i);
+			gp = find_geom(classp, name);
+			if (gp != NULL)
+				gpart_show_geom(gp);
+			else
+				errx(EXIT_FAILURE, "No such geom: %s.", name);
+		}
+	} else {
+		LIST_FOREACH(gp, &classp->lg_geom, lg_geom) {
+			gpart_show_geom(gp);
+		}
+	}
+	geom_deletetree(&mesh);
+}

sbin/geom/class/part/gpart.8

@@ -24,7 +24,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd May 15, 2007
+.Dd Oct 20, 2007
 .Dt GPART 8
 .Os
 .Sh NAME
@@ -37,12 +37,15 @@ lines in your kernel configuration file:
 .Bd -ragged -offset indent
 .Cd "options GEOM_PART_APM"
 .Cd "options GEOM_PART_GPT"
+.Cd "options GEOM_PART_MBR"
 .Ed
 .Pp
 The GEOM_PART_APM option adds support for the Apple Partition Map (APM)
-found on Apple Macintosh computers, and the GEOM_PART_GPT option adds
+found on Apple Macintosh computers.
-support for the GUID Partition Table (GPT) found on Intel Itanium
+The GEOM_PART_GPT option adds support for the GUID Partition Table (GPT)
-computers and Intel-based Macintosh computers.
+found on Intel Itanium computers and Intel-based Macintosh computers.
+The GEOM_PART_MBR option adds support for the Master Boot Record (MBR)
+found on PCs and used on many removable media.
 .Pp
 Usage of the
 .Xr gpart 8
@@ -88,6 +91,10 @@ utility:
 .Op Fl t Ar type
 .Op Fl f Ar flags
 .Ar geom
+.\" ==== SHOW ====
+.Nm
+.Cm show
+.Op Ar geom ...
 .\" ==== UNDO ====
 .Nm
 .Cm undo
@@ -223,6 +230,10 @@ Additional operational flags.
 See the section entitled "Operational flags" below for a discussion
 about its use.
 .El
+.\" ==== SHOW ====
+.It Cm show
+Show the current partition information of the specified geoms
+or all geoms if none are specified.
 .\" ==== UNDO ====
 .It Cm undo
 Revert any pending changes.
@@ -254,7 +265,7 @@ A FreeBSD partition that uses the BSD disklabel to sub-divide the
 partition into file systems.
 This is a legacy partition type and should not be used for the APM
 or GPT schemes.
-The scheme-specific types are "!FreeBSD" for APM, and
+The scheme-specific types are "!165" for MBR, "!FreeBSD" for APM, and
 "!516e7cb4-6ecf-11d6-8ff8-00022d09712b" for GPT.
 .It freebsd-swap
 A FreeBSD partition dedicated to swap space.
@@ -304,5 +315,11 @@ The
 .Nm
 utility appeared in
 .Fx 7.0 .
+.Sh BUGS
+The MBR partitioning scheme cannot yet be used to create a bootable
+MBR. 
+.Pp
+Support for the PC98 or Sun partitioning schemes is not yet present.
+The BSD disklabel is also not supported yet.
 .Sh AUTHORS
 .An Marcel Moolenaar Aq marcel@FreeBSD.org