Move devpath scan to separate file.

git-svn-id: https://cryptsetup.googlecode.com/svn/trunk@529 36d66b0a-2a48-0410-832c-cd162a569da5

lib/utils_devpath.c

@@ -0,0 +1,142 @@
+/*
+ * devname - search for device name
+ *
+ * Copyright (C) 2004, Christophe Saout <christophe@saout.de>
+ * Copyright (C) 2004-2007, Clemens Fruhwirth <clemens@endorphin.org>
+ * Copyright (C) 2009-2011, Red Hat, Inc. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU 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 <string.h>
+#include <stdio.h>
+#include <dirent.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include "internal.h"
+
+#define DEVICE_DIR	"/dev"
+
+static char *__lookup_dev(char *path, dev_t dev, int dir_level, const int max_level)
+{
+	struct dirent *entry;
+	struct stat st;
+	char *ptr;
+	char *result = NULL;
+	DIR *dir;
+	int space;
+
+	/* Ignore strange nested directories */
+	if (dir_level > max_level)
+		return NULL;
+
+	path[PATH_MAX - 1] = '\0';
+	ptr = path + strlen(path);
+	*ptr++ = '/';
+	*ptr = '\0';
+	space = PATH_MAX - (ptr - path);
+
+	dir = opendir(path);
+	if (!dir)
+		return NULL;
+
+	while((entry = readdir(dir))) {
+		if (entry->d_name[0] == '.' ||
+		    !strncmp(entry->d_name, "..", 2))
+			continue;
+
+		strncpy(ptr, entry->d_name, space);
+		if (stat(path, &st) < 0)
+			continue;
+
+		if (S_ISDIR(st.st_mode)) {
+			result = __lookup_dev(path, dev, dir_level + 1, max_level);
+			if (result)
+				break;
+		} else if (S_ISBLK(st.st_mode)) {
+			/* workaround: ignore dm-X devices, these are internal kernel names */
+			if (dir_level == 0 && !strncmp(entry->d_name, "dm-", 3))
+				continue;
+			if (st.st_rdev == dev) {
+				result = strdup(path);
+				break;
+			}
+		}
+	}
+
+	closedir(dir);
+	return result;
+}
+
+static char *lookup_dev_old(const char *dev_id)
+{
+	int major, minor;
+	dev_t dev;
+	char *result = NULL, buf[PATH_MAX + 1];
+
+	if (sscanf(dev_id, "%d:%d", &major, &minor) != 2)
+		return NULL;
+
+	dev = makedev(major, minor);
+	strncpy(buf, DEVICE_DIR, PATH_MAX);
+	buf[PATH_MAX] = '\0';
+
+	/* First try low level device */
+	if ((result = __lookup_dev(buf, dev, 0, 0)))
+		return result;
+
+	/* If it is dm, try DM dir  */
+	if (dm_is_dm_device(major)) {
+		strncpy(buf, dm_get_dir(), PATH_MAX);
+		if ((result = __lookup_dev(buf, dev, 0, 0)))
+			return result;
+	}
+
+	strncpy(buf, DEVICE_DIR, PATH_MAX);
+	result = __lookup_dev(buf, dev, 0, 4);
+
+	/* If not found, return NULL */
+	return result;
+}
+
+char *crypt_lookup_dev(const char *dev_id)
+{
+	char link[PATH_MAX], path[PATH_MAX], *devname;
+	struct stat st;
+	ssize_t len;
+
+	if (snprintf(path, sizeof(path), "/sys/dev/block/%s", dev_id) < 0)
+		return NULL;
+
+	len = readlink(path, link, sizeof(link));
+	if (len < 0) {
+		if (stat("/sys/dev/block", &st) < 0)
+			return lookup_dev_old(dev_id);
+		return NULL;
+	}
+
+	link[len] = '\0';
+	devname = strrchr(link, '/');
+	if (!devname)
+		return NULL;
+	devname++;
+
+	if (!strncmp(devname, "dm-", 3))
+		return dm_device_path(dev_id);
+
+	if (snprintf(path, sizeof(path), "/dev/%s", devname) < 0)
+		return NULL;
+
+	return strdup(path);
+}