Missed file from previous checkin.

lib/device/dev-swap.c

@@ -0,0 +1,87 @@
+/*
+ * Copyright (C) 2009 Red Hat, Inc. All rights reserved.
+ *
+ * This file is part of LVM2.
+ *
+ * This copyrighted material is made available to anyone wishing to use,
+ * modify, copy, or redistribute it subject to the terms and conditions
+ * of the GNU Lesser General Public License v.2.1.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include "lib.h"
+#include "metadata.h"
+#include "xlate.h"
+#include "filter.h"
+
+#ifdef linux
+
+#define MAX_PAGESIZE	(64 * 1024)
+#define SIGNATURE_SIZE  10
+
+static int
+_swap_detect_signature(const char *buf)
+{
+	if (memcmp(buf, "SWAP-SPACE", 10) == 0 ||
+            memcmp(buf, "SWAPSPACE2", 10) == 0)
+		return 1;
+
+	if (memcmp(buf, "S1SUSPEND", 9) == 0 ||
+	    memcmp(buf, "S2SUSPEND", 9) == 0 ||
+	    memcmp(buf, "ULSUSPEND", 9) == 0 ||
+	    memcmp(buf, "\xed\xc3\x02\xe9\x98\x56\xe5\x0c", 8) == 0)
+		return 1;
+
+	return 0;
+}
+
+int dev_is_swap(struct device *dev, uint64_t *signature)
+{
+	char buf[10];
+	uint64_t size;
+	int page;
+
+	if (!dev_get_size(dev, &size)) {
+		stack;
+		return -1;
+	}
+
+	if (!dev_open(dev)) {
+		stack;
+		return -1;
+	}
+
+	*signature = 0;
+
+	for (page = 0x1000; page <= MAX_PAGESIZE; page <<= 1) {
+		/*
+		 * skip 32k pagesize since this does not seem to be supported
+		 */
+		if (page == 0x8000)
+			continue;
+		if (size < page)
+			break;
+		if (!dev_read(dev, page - SIGNATURE_SIZE,
+			      SIGNATURE_SIZE, buf)) {
+			stack;
+			return -1;
+		}
+		if (_swap_detect_signature(buf)) {
+			*signature = page - SIGNATURE_SIZE;
+			break;
+		}
+	}
+
+	if (!dev_close(dev))
+		stack;
+
+	if (*signature)
+		return 1;
+
+	return 0;
+}
+
+#endif