From c0b2521a829e83f8954093644ab2dd78353037e7 Mon Sep 17 00:00:00 2001
From: Peter Rajnoha <prajnoha@redhat.com>
Date: Wed, 15 Feb 2012 12:23:15 +0000
Subject: [PATCH] Add DM_DEFAULT_NAME_MANGLING_MODE env. variable to override
 configured value.

Just in case of emergency when name mangling code causes any problems so
we can override the default value and switch off the mangling globally.
---
 WHATS_NEW_DM         |  2 ++
 libdm/libdevmapper.h |  6 ++++++
 libdm/libdm-common.c | 20 +++++++++++++++++++-
 libdm/libdm-common.h |  2 ++
 4 files changed, 29 insertions(+), 1 deletion(-)

diff --git a/WHATS_NEW_DM b/WHATS_NEW_DM
index 1103380de..27d8972d4 100644
--- a/WHATS_NEW_DM
+++ b/WHATS_NEW_DM
@@ -1,5 +1,7 @@
 Version 1.02.71 - 
 ====================================
+  Add DM_DEFAULT_NAME_MANGLING_MODE env. variable to override configured value.
+  Add dm_lib_init to automatically initialise device-mapper library on load.
   Replace any '\' char with '\\' in table specification on input.
   Add mangle command to dmsetup to provide renaming to correct mangled form.
   Add 'mangled_name' and 'unmangled_name' fields to dmsetup info -c -o.
diff --git a/libdm/libdevmapper.h b/libdm/libdevmapper.h
index e9f84ea4f..fe6c42eed 100644
--- a/libdm/libdevmapper.h
+++ b/libdm/libdevmapper.h
@@ -365,6 +365,12 @@ int dm_device_has_holders(uint32_t major, uint32_t minor);
  */
 int dm_device_has_mounted_fs(uint32_t major, uint32_t minor);
 
+
+/*
+ * Initialise library
+ */
+void dm_lib_init(void) __attribute__((constructor));
+
 /*
  * Release library resources
  */
diff --git a/libdm/libdm-common.c b/libdm/libdm-common.c
index b5ebcfd83..54a893a64 100644
--- a/libdm/libdm-common.c
+++ b/libdm/libdm-common.c
@@ -43,6 +43,8 @@
 #  include <selinux/label.h>
 #endif
 
+#define DM_DEFAULT_NAME_MANGLING_MODE_ENV_VAR_NAME "DM_DEFAULT_NAME_MANGLING_MODE"
+
 #define DEV_DIR "/dev/"
 
 #ifdef UDEV_SYNC_SUPPORT
@@ -66,7 +68,7 @@ static char _default_uuid_prefix[DM_MAX_UUID_PREFIX_LEN + 1] = "LVM-";
 
 static int _verbose = 0;
 static int _suspended_dev_counter = 0;
-static int _name_mangling_mode = DEFAULT_DM_NAME_MANGLING;
+static int _name_mangling_mode = -1;
 
 #ifdef HAVE_SELINUX_LABEL_H
 static struct selabel_handle *_selabel_handle = NULL;
@@ -79,6 +81,22 @@ static int _sync_with_udev = 1;
 static int _udev_checking = 1;
 #endif
 
+void dm_lib_init(void)
+{
+	const char *env;
+
+	env = getenv(DM_DEFAULT_NAME_MANGLING_MODE_ENV_VAR_NAME);
+	if (env && *env) {
+		if (!strcasecmp(env, "none"))
+			_name_mangling_mode = DM_STRING_MANGLING_NONE;
+		else if (!strcasecmp(env, "auto"))
+			_name_mangling_mode = DM_STRING_MANGLING_AUTO;
+		else if (!strcasecmp(env, "hex"))
+			_name_mangling_mode = DM_STRING_MANGLING_HEX;
+	} else
+		_name_mangling_mode = DEFAULT_DM_NAME_MANGLING;
+}
+
 /*
  * Library users can provide their own logging
  * function.
diff --git a/libdm/libdm-common.h b/libdm/libdm-common.h
index 77d0b1f48..ce9b434ff 100644
--- a/libdm/libdm-common.h
+++ b/libdm/libdm-common.h
@@ -18,6 +18,8 @@
 
 #include "libdevmapper.h"
 
+#define DM_DEFAULT_NAME_MANGLING_MODE_ENV_VAR_NAME "DM_DEFAULT_NAME_MANGLING_MODE"
+
 #define DEV_NAME(dmt) (dmt->mangled_dev_name ? : dmt->dev_name)
 
 int mangle_name(const char *str, size_t len, char *buf,