[Drbd-dev] Modifying the usermode helper program executed by DRBD

[Drbd-dev] Modifying the usermode helper program executed by DRBD

[Graham, Simon]

[-- Attachment #1.1: Type: text/plain, Size: 584 bytes --]

Currently, the DRBD driver is hardcoded to execute "/sbin/drbdadm" as
the usermode helper program - this means that it is not possible to have
drbdadm installed in a different location or to replace it with another
program (such as a different front end to drbdsetup).

 

To enable this, I've created a simple patch which adds a sysfs file
/sys/module/drbd/parameters/usermode_helper which can be updated with
the path to the executable to be run as the usermode helper - the
default value of this is "/sbin/drbdadm" so the default behavior is
unchanged.

 

Simon


[-- Attachment #1.2: Type: text/html, Size: 2381 bytes --]

[-- Attachment #2: drbd-usermode-helper.patch --]
[-- Type: application/octet-stream, Size: 1714 bytes --]

Index: src/drbd/drbd_nl.c
===================================================================
--- src/drbd/drbd_nl.c	(revision 15638)
+++ src/drbd/drbd_nl.c	(working copy)
@@ -164,7 +164,7 @@
 int drbd_khelper(drbd_dev *mdev, char* cmd)
 {
 	char mb[12];
-	char *argv[] = {"/sbin/drbdadm", cmd, mb, NULL };
+	char *argv[] = {usermode_helper, cmd, mb, NULL };
 	static char *envp[] = { "HOME=/",
 				"TERM=linux",
 				"PATH=/sbin:/usr/sbin:/bin:/usr/bin",
@@ -172,8 +172,10 @@
 
 	snprintf(mb,12,"minor-%d",mdev_to_minor(mdev));
 
+	INFO("helper command: %s %s\n",usermode_helper,cmd);
+
 	drbd_bcast_ev_helper(mdev,cmd);
-	return call_usermodehelper("/sbin/drbdadm",argv,envp,1);
+	return call_usermodehelper(usermode_helper,argv,envp,1);
 }
 
 drbd_disks_t drbd_try_outdate_peer(drbd_dev *mdev)
Index: src/drbd/drbd_main.c
===================================================================
--- src/drbd/drbd_main.c	(revision 15638)
+++ src/drbd/drbd_main.c	(working copy)
@@ -119,6 +119,14 @@
 module_param(trace_devs,int,0644);
 #endif
 
+
+// Module parameter for setting the user mode helper program
+// to run. Default is /sbin/drbdadm
+
+char usermode_helper[80] = "/sbin/drbdadm";
+
+module_param_string(usermode_helper, usermode_helper, sizeof(usermode_helper), 0644);
+
 // global panic flag
 volatile int drbd_did_panic = 0;
 
Index: src/drbd/drbd_int.h
===================================================================
--- src/drbd/drbd_int.h	(revision 15638)
+++ src/drbd/drbd_int.h	(working copy)
@@ -51,6 +51,8 @@
 extern int fault_devs;
 #endif
 
+extern char usermode_helper[];
+
 #include <linux/major.h>
 #ifdef DRBD_MAJOR
 # warning "FIXME. DRBD_MAJOR is now officially defined in major.h"

Re: [Drbd-dev] Modifying the usermode helper program executed by DRBD

[Philipp Reisner]

On Wednesday 27 June 2007 21:12:56 Graham, Simon wrote:
> Currently, the DRBD driver is hardcoded to execute "/sbin/drbdadm" as
> the usermode helper program - this means that it is not possible to have
> drbdadm installed in a different location or to replace it with another
> program (such as a different front end to drbdsetup).
>
>
>
> To enable this, I've created a simple patch which adds a sysfs file
> /sys/module/drbd/parameters/usermode_helper which can be updated with
> the path to the executable to be run as the usermode helper - the
> default value of this is "/sbin/drbdadm" so the default behavior is
> unchanged.
>
>

Ack, it is in. Thanks!

-Phil
-- 
: Dipl-Ing Philipp Reisner                      Tel +43-1-8178292-50 :
: LINBIT Information Technologies GmbH          Fax +43-1-8178292-82 :
: Vivenotgasse 48, 1120 Vienna, Austria        http://www.linbit.com :