1 files changed, 144 insertions, 0 deletions
diff --git a/libblkid/src/topology/lvm.c b/libblkid/src/topology/lvm.c
new file mode 100644
index 0000000..6ab7a50
--- /dev/null
+++ b/libblkid/src/topology/lvm.c
@@ -0,0 +1,144 @@
+/*
+ * lvm topology
+ * -- this is fallback for old systems where the topology information is not
+ *    exported by sysfs
+ *
+ * Copyright (C) 2009 Karel Zak <kzak@redhat.com>
+ *
+ * This file may be redistributed under the terms of the
+ * GNU Lesser General Public License.
+ *
+ */
+#include <errno.h>
+#include <fcntl.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include "topology.h"
+
+#ifndef LVM_BLK_MAJOR
+# define LVM_BLK_MAJOR     58
+#endif
+
+static int is_lvm_device(dev_t devno)
+{
+	if (major(devno) == LVM_BLK_MAJOR)
+		return 1;
+	return blkid_driver_has_major("lvm", major(devno));
+}
+
+static int probe_lvm_tp(blkid_probe pr,
+		const struct blkid_idmag *mag __attribute__((__unused__)))
+{
+	const char *paths[] = {
+		"/usr/local/sbin/lvdisplay",
+		"/usr/sbin/lvdisplay",
+		"/sbin/lvdisplay"
+	};
+	int lvpipe[] = { -1, -1 }, stripes = 0, stripesize = 0;
+	FILE *stream = NULL;
+	char *cmd = NULL, *devname = NULL, buf[1024];
+	size_t i;
+	dev_t devno = blkid_probe_get_devno(pr);
+
+	if (!devno)
+		goto nothing;		/* probably not a block device */
+	if (!is_lvm_device(devno))
+		goto nothing;
+
+	for (i = 0; i < ARRAY_SIZE(paths); i++) {
+		struct stat sb;
+		if (stat(paths[i], &sb) == 0) {
+			cmd = (char *) paths[i];
+			break;
+		}
+	}
+
+	if (!cmd)
+		goto nothing;
+
+	devname = blkid_devno_to_devname(devno);
+	if (!devname)
+		goto nothing;
+
+	if (pipe(lvpipe) < 0) {
+		DBG(LOWPROBE, ul_debug("Failed to open pipe: errno=%d", errno));
+		goto nothing;
+	}
+
+	switch (fork()) {
+	case 0:
+	{
+		char *lvargv[3];
+
+		/* Plumbing */
+		close(lvpipe[0]);
+
+		if (lvpipe[1] != STDOUT_FILENO)
+			dup2(lvpipe[1], STDOUT_FILENO);
+
+		if (drop_permissions() != 0)
+			 exit(1);
+
+		lvargv[0] = cmd;
+		lvargv[1] = devname;
+		lvargv[2] = NULL;
+
+		execv(lvargv[0], lvargv);
+
+		DBG(LOWPROBE, ul_debug("Failed to execute %s: errno=%d", cmd, errno));
+		exit(1);
+	}
+	case -1:
+		DBG(LOWPROBE, ul_debug("Failed to forking: errno=%d", errno));
+		goto nothing;
+	default:
+		break;
+	}
+
+	stream = fdopen(lvpipe[0], "r" UL_CLOEXECSTR);
+	if (!stream)
+		goto nothing;
+
+	while (fgets(buf, sizeof(buf), stream) != NULL) {
+		if (!strncmp(buf, "Stripes", 7))
+			ignore_result( sscanf(buf, "Stripes %d", &stripes) );
+
+		if (!strncmp(buf, "Stripe size", 11))
+			ignore_result( sscanf(buf, "Stripe size (KByte) %d", &stripesize) );
+	}
+
+	if (!stripes)
+		goto nothing;
+
+	blkid_topology_set_minimum_io_size(pr, stripesize << 10);
+	blkid_topology_set_optimal_io_size(pr, (stripes * stripesize) << 10);
+
+	free(devname);
+	fclose(stream);
+	close(lvpipe[1]);
+	return 0;
+
+nothing:
+	free(devname);
+	if (stream)
+		fclose(stream);
+	else if (lvpipe[0] != -1)
+		close(lvpipe[0]);
+	if (lvpipe[1] != -1)
+		close(lvpipe[1]);
+	return 1;
+}
+
+const struct blkid_idinfo lvm_tp_idinfo =
+{
+	.name		= "lvm",
+	.probefunc	= probe_lvm_tp,
+	.magics		= BLKID_NONE_MAGIC
+};
+