From: Karel Zak <kzak@redhat.com>
Date: Wed, 23 Sep 2009 19:27:01 +0000 (+0200)
Subject: libblkid: add LVM topology support (for old kernels)
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7d0c1c45a911be05a35296961c585e9488671dce;p=util-linux

libblkid: add LVM topology support (for old kernels)

Signed-off-by: Karel Zak <kzak@redhat.com>
---

diff --git a/shlibs/blkid/src/topology/Makefile.am b/shlibs/blkid/src/topology/Makefile.am
index ffaf58dc..05a8ac9f 100644
--- a/shlibs/blkid/src/topology/Makefile.am
+++ b/shlibs/blkid/src/topology/Makefile.am
@@ -9,4 +9,5 @@ libblkid_topology_la_SOURCES =	topology.c \
 				sysfs.c \
 				md.c \
 				dm.c \
-				evms.c
+				evms.c \
+				lvm.c
diff --git a/shlibs/blkid/src/topology/lvm.c b/shlibs/blkid/src/topology/lvm.c
new file mode 100644
index 00000000..0ea984a8
--- /dev/null
+++ b/shlibs/blkid/src/topology/lvm.c
@@ -0,0 +1,149 @@
+/*
+ * lvm topology
+ * -- this is fallback for old systems where the toplogy information are 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/ioctl.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)
+{
+	const char *paths[] = {
+		"/usr/local/sbin/lvdisplay",
+		"/usr/sbin/lvdisplay",
+		"/sbin/lvdisplay"
+	};
+	int i, lvpipe[] = { -1, -1 }, stripes = 0, stripesize = 0;
+	FILE *stream = NULL;
+	char *cmd = NULL, *devname = NULL, buf[1024];
+	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(DEBUG_LOWPROBE,
+			printf("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);
+
+		/* The libblkid library could linked with setuid programs */
+		if (setgid(getgid()) < 0)
+			 exit(1);
+		if (setuid(getuid()) < 0)
+			 exit(1);
+
+		lvargv[0] = cmd;
+		lvargv[1] = devname;
+		lvargv[2] = NULL;
+
+		execv(lvargv[0], lvargv);
+
+		DBG(DEBUG_LOWPROBE,
+			printf("Failed to execute %s: errno=%d", cmd, errno));
+		exit(1);
+	}
+	case -1:
+		DBG(DEBUG_LOWPROBE,
+			printf("Failed to forking: errno=%d", errno));
+		goto nothing;
+	default:
+		break;
+	}
+
+	stream = fdopen(lvpipe[0], "r");
+	if (!stream)
+		goto nothing;
+
+	while (fgets(buf, sizeof(buf), stream) != NULL) {
+		if (!strncmp(buf, "Stripes", 7))
+			sscanf(buf, "Stripes %d", &stripes);
+
+		if (!strncmp(buf, "Stripe size", 11))
+			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
+};
+
diff --git a/shlibs/blkid/src/topology/topology.c b/shlibs/blkid/src/topology/topology.c
index ab2ecd0d..f4cd3219 100644
--- a/shlibs/blkid/src/topology/topology.c
+++ b/shlibs/blkid/src/topology/topology.c
@@ -62,6 +62,7 @@ static const struct blkid_idinfo *idinfos[] =
 	&sysfs_tp_idinfo,
 	&md_tp_idinfo,
 	&dm_tp_idinfo,
+	&lvm_tp_idinfo,
 	&evms_tp_idinfo
 };
 
diff --git a/shlibs/blkid/src/topology/topology.h b/shlibs/blkid/src/topology/topology.h
index 48d3f26f..98321394 100644
--- a/shlibs/blkid/src/topology/topology.h
+++ b/shlibs/blkid/src/topology/topology.h
@@ -14,6 +14,7 @@ extern const struct blkid_idinfo sysfs_tp_idinfo;
 extern const struct blkid_idinfo md_tp_idinfo;
 extern const struct blkid_idinfo dm_tp_idinfo;
 extern const struct blkid_idinfo evms_tp_idinfo;
+extern const struct blkid_idinfo lvm_tp_idinfo;
 
 #endif /* BLKID_TOPOLOGY_H */