diff --git a/liboath/global.c b/liboath/global.c

index d442cf3..cfe1cee 100644

--- a/liboath/global.c

+++ b/liboath/global.c

@@ -25,9 +25,12 @@

 #include <stdio.h>		/* For snprintf, getline. */

 #include <string.h>		/* For strverscmp. */

+#include <stdlib.h>		/* For free. */

 #include "gc.h"

+char *oath_lockfile_path = NULL;

+

 /**

  * oath_init:

  *

@@ -52,6 +55,8 @@ oath_init (void)

   if (gc_init () != GC_OK)

     return OATH_CRYPTO_ERROR;

+  oath_lockfile_path = NULL;

+

   return OATH_OK;

 }

@@ -71,6 +76,11 @@ oath_done (void)

 {

   gc_done ();

+  if (oath_lockfile_path)

+  {

+    free(oath_lockfile_path);

+    oath_lockfile_path = NULL;

+  }

   return OATH_OK;

 }

@@ -99,3 +109,23 @@ oath_check_version (const char *req_version)

   return NULL;

 }

+

+int

+oath_set_lockfile_path(const char *lockfile)

+{

+  int l;

+

+  if (oath_lockfile_path)

+  {

+    free(oath_lockfile_path);

+    oath_lockfile_path = NULL;

+  }

+

+  if (lockfile)

+  {

+    l = asprintf (&oath_lockfile_path, "%s", lockfile);

+    if (oath_lockfile_path == NULL || ((size_t) l) != strlen (lockfile))

+        return OATH_PRINTF_ERROR;

+  }

+  return OATH_OK;

+}

diff --git a/liboath/liboath.map b/liboath/liboath.map

index 2f247ff..e8f8cdf 100644

--- a/liboath/liboath.map

+++ b/liboath/liboath.map

@@ -75,6 +75,7 @@ LIBOATH_2.2.0

   global:

     oath_totp_validate3;

     oath_totp_validate3_callback;

+    oath_set_lockfile_path;

 } LIBOATH_1.12.0;

 LIBOATH_2.6.0

diff --git a/liboath/oath.h b/liboath/oath.h

index fe93b9e..6660fb3 100644

--- a/liboath/oath.h

+++ b/liboath/oath.h

@@ -159,11 +159,15 @@ typedef enum

 /* Global */

+extern char *oath_lockfile_path;

+

 extern OATHAPI int oath_init (void);

 extern OATHAPI int oath_done (void);

 extern OATHAPI const char *oath_check_version (const char *req_version);

+extern OATHAPI int oath_set_lockfile_path(const char *lockfile);

+

 /* Error handling */

 extern OATHAPI const char *oath_strerror (int err);

diff --git a/liboath/oath.h.in b/liboath/oath.h.in

index eee284c..536cd30 100644

--- a/liboath/oath.h.in

+++ b/liboath/oath.h.in

@@ -159,11 +159,15 @@ typedef enum

 /* Global */

+extern char *oath_lockfile_path;

+

 extern OATHAPI int oath_init (void);

 extern OATHAPI int oath_done (void);

 extern OATHAPI const char *oath_check_version (const char *req_version);

+extern OATHAPI int oath_set_lockfile_path(const char *lockfile);

+

 /* Error handling */

 extern OATHAPI const char *oath_strerror (int err);

diff --git a/liboath/usersfile.c b/liboath/usersfile.c

index ef03f39..7cc4347 100644

--- a/liboath/usersfile.c

+++ b/liboath/usersfile.c

@@ -323,9 +323,18 @@ update_usersfile (const char *usersfile,

   {

     int l;

-    l = asprintf (&lockfile, "%s.lock", usersfile);

-    if (lockfile == NULL || ((size_t) l) != strlen (usersfile) + 5)

-      return OATH_PRINTF_ERROR;

+    if (oath_lockfile_path)

+    {

+      l = asprintf (&lockfile, "%s", oath_lockfile_path);

+      if (lockfile == NULL || ((size_t) l) != strlen (oath_lockfile_path))

+        return OATH_PRINTF_ERROR;

+    }

+    else

+    {

+      l = asprintf (&lockfile, "%s.lock", usersfile);

+      if (lockfile == NULL || ((size_t) l) != strlen (usersfile) + 5)

+        return OATH_PRINTF_ERROR;

+    }

     lockfh = fopen (lockfile, "w");

     if (!lockfh)

diff --git a/pam_oath/pam_oath.c b/pam_oath/pam_oath.c

index b2afed7..307ffc2 100644

--- a/pam_oath/pam_oath.c

+++ b/pam_oath/pam_oath.c

@@ -75,6 +75,7 @@ struct cfg

   int try_first_pass;

   int use_first_pass;

   char *usersfile;

+  char *lockfile;

   unsigned digits;

   unsigned window;

 };

@@ -89,6 +90,7 @@ parse_cfg (int flags, int argc, const char **argv, struct cfg *cfg)

   cfg->try_first_pass = 0;

   cfg->use_first_pass = 0;

   cfg->usersfile = NULL;

+  cfg->lockfile = NULL;

   cfg->digits = -1;

   cfg->window = 5;

@@ -104,6 +106,8 @@ parse_cfg (int flags, int argc, const char **argv, struct cfg *cfg)

 	cfg->use_first_pass = 1;

       if (strncmp (argv[i], "usersfile=", 10) == 0)

 	cfg->usersfile = (char *) argv[i] + 10;

+      if (strncmp (argv[i], "lockfile=", 9) == 0)

+	cfg->lockfile = (char *) argv[i] + 9;

       if (strncmp (argv[i], "digits=", 7) == 0)

 	cfg->digits = atoi (argv[i] + 7);

       if (strncmp (argv[i], "window=", 7) == 0)

@@ -129,6 +133,7 @@ parse_cfg (int flags, int argc, const char **argv, struct cfg *cfg)

       D (("try_first_pass=%d", cfg->try_first_pass));

       D (("use_first_pass=%d", cfg->use_first_pass));

       D (("usersfile=%s", cfg->usersfile ? cfg->usersfile : "(null)"));

+      D (("lockfile=%s", cfg->lockfile ? cfg->lockfile : "(null)"));

       D (("digits=%d", cfg->digits));

       D (("window=%d", cfg->window));

     }

@@ -327,6 +332,17 @@ pam_sm_authenticate (pam_handle_t * pamh,

       goto done;

     }

+  if (cfg.lockfile)

+    rc = oath_set_lockfile_path(cfg.lockfile);

+  else

+    rc = oath_set_lockfile_path("/var/lock/pam_oath.lock");

+  if (rc != OATH_OK)

+    {

+      DBG (("oath_set_lockfile_path() failed (%d)", rc));

+      retval = PAM_AUTHINFO_UNAVAIL;

+      goto done;

+    }

+

   if (password == NULL)

     {

       retval = pam_get_item (pamh, PAM_CONV, (const void **) &conv;;