Add 'geli version' subcommand, which will print GELI metadata version of each

given GEOM provider or if not providers are given it will print versions
supported by userland geli(8) utility and by ELI GEOM class.

MFC after:	3 days

sbin/geom/class/eli/geli.8

@@ -134,6 +134,9 @@ utility:
 .Fl s Ar oldsize
 .Ar prov
 .Nm
+.Cm version
+.Op Ar prov ...
+.Nm
 .Cm clear
 .Op Fl v
 .Ar prov ...
@@ -597,6 +600,18 @@ Additional options include:
 .It Fl s Ar oldsize
 The size of the provider before it was resized.
 .El
+.It Cm version
+If no arguments are given, the
+.Cm version
+subcommand will print the version of
+.Nm
+userland utility as well as the version of the
+.Nm ELI
+GEOM class.
+.Pp
+If GEOM providers are specified, the
+.Cm version
+subcommand will print metadata version used by each of them.
 .It Cm clear
 Clear metadata from the given providers.
 .It Cm dump

sbin/geom/class/eli/geom_eli.c

@@ -72,6 +72,7 @@ static void eli_kill(struct gctl_req *req);
 static void eli_backup(struct gctl_req *req);
 static void eli_restore(struct gctl_req *req);
 static void eli_resize(struct gctl_req *req);
+static void eli_version(struct gctl_req *req);
 static void eli_clear(struct gctl_req *req);
 static void eli_dump(struct gctl_req *req);
 
@@ -96,6 +97,7 @@ static int eli_backup_create(struct gctl_req *req, const char *prov,
  * backup [-v] prov file
  * restore [-fv] file prov
  * resize [-v] -s oldsize prov
+ * version [prov ...]
  * clear [-v] prov ...
  * dump [-v] prov ...
  */
@@ -241,6 +243,9 @@ struct g_command class_commands[] = {
 	    },
 	    "[-v] -s oldsize prov"
 	},
+	{ "version", G_FLAG_LOADKLD, eli_main, G_NULL_OPTS,
+	    "[prov ...]"
+	},
 	{ "clear", G_FLAG_VERBOSE, eli_main, G_NULL_OPTS,
 	    "[-v] prov ..."
 	},
@@ -309,6 +314,8 @@ eli_main(struct gctl_req *req, unsigned int flags)
 		eli_restore(req);
 	else if (strcmp(name, "resize") == 0)
 		eli_resize(req);
+	else if (strcmp(name, "version") == 0)
+		eli_version(req);
 	else if (strcmp(name, "dump") == 0)
 		eli_dump(req);
 	else if (strcmp(name, "clear") == 0)
@@ -1523,6 +1530,46 @@ eli_resize(struct gctl_req *req)
 	}
 }
 
+static void
+eli_version(struct gctl_req *req)
+{
+	struct g_eli_metadata md;
+	const char *name;
+	unsigned int version;
+	int error, i, nargs;
+
+	nargs = gctl_get_int(req, "nargs");
+
+	if (nargs == 0) {
+		unsigned int kernver;
+		ssize_t size;
+
+		size = sizeof(kernver);
+		if (sysctlbyname("kern.geom.eli.version", &kernver, &size,
+		    NULL, 0) == -1) {
+			warn("Unable to obtain GELI kernel version");
+		} else {
+			printf("kernel: %u\n", kernver);
+		}
+		printf("userland: %u\n", G_ELI_VERSION);
+		return;
+	}
+
+	for (i = 0; i < nargs; i++) {
+		name = gctl_get_ascii(req, "arg%d", i);
+		error = g_metadata_read(name, (unsigned char *)&md,
+		    sizeof(md), G_ELI_MAGIC);
+		if (error != 0) {
+			warn("%s: Unable to read metadata: %s.", name,
+			    strerror(error));
+			gctl_error(req, "Not fully done.");
+			continue;
+		}
+		version = le32dec(&md.md_version);
+		printf("%s: %u\n", name, version);
+	}
+}
+
 static void
 eli_clear(struct gctl_req *req)
 {