diff -up gdbm-1.8.3/dbmopen.c.dbmlock gdbm-1.8.3/dbmopen.c

--- gdbm-1.8.3/dbmopen.c.dbmlock	1999-05-19 02:16:05.000000000 +0200

+++ gdbm-1.8.3/dbmopen.c	2011-01-03 16:17:13.847173371 +0100

@@ -35,6 +35,28 @@

 #include "gdbmerrno.h"

 #include "extern.h"

+static int

+get_env_bool(env_var, def)

+      const char *env_var;

+      int def;

+{

+  const char *v = getenv(env_var);

+  if (!v)

+    return def;

+

+  if (!strcasecmp(v, "yes") ||

+      !strcasecmp(v, "true") ||

+      !strcasecmp(v, "on"))

+    return 1;

+

+  if (!strcasecmp(v, "no") ||

+      !strcasecmp(v, "false") ||

+      !strcasecmp(v, "off"))

+    return 0;

+

+  return !!atoi(v);

+}

+

 /* Initialize ndbm system.  FILE is a pointer to the file name.  In

    standard dbm, the database is found in files called FILE.pag and

    FILE.dir.  To make gdbm compatable with dbm using the dbminit call,

@@ -62,7 +84,7 @@ dbm_open (file, flags, mode)

   char* dir_file;	    /* Used to construct "file.dir". */

   struct stat dir_stat;	    /* Stat information for "file.dir". */

   gdbm_file_info *temp_dbf;  /* Temporary file pointer storage. */

-

+  int gdbm_mode = 0;

   /* Prepare the correct names of "file.pag" and "file.dir". */

   pag_file = (char *) malloc (strlen (file)+5);

@@ -77,26 +99,22 @@ dbm_open (file, flags, mode)

   strcat (pag_file, ".pag");

   strcpy (dir_file, file);

   strcat (dir_file, ".dir");

-  

+

+  if (!get_env_bool("NDBM_LOCK", 1))

+      gdbm_mode |= GDBM_NOLOCK;

   /* Call the actual routine, saving the pointer to the file information. */

   flags &= O_RDONLY | O_RDWR | O_CREAT | O_TRUNC;

   if (flags == O_RDONLY)

-    {

-      temp_dbf = gdbm_open (pag_file, 0, GDBM_READER, 0, NULL);

-    }

+    gdbm_mode |= GDBM_READER;

   else if (flags == (O_RDWR | O_CREAT))

-    {

-      temp_dbf = gdbm_open (pag_file, 0, GDBM_WRCREAT, mode, NULL);

-    }

-  else if ( (flags & O_TRUNC) == O_TRUNC)

-    {

-      temp_dbf = gdbm_open (pag_file, 0, GDBM_NEWDB, mode, NULL);

-    }

+    gdbm_mode |= GDBM_WRCREAT;

+  else if ((flags & O_TRUNC) == O_TRUNC)

+    gdbm_mode |= GDBM_NEWDB;

   else

-    {

-      temp_dbf = gdbm_open (pag_file, 0, GDBM_WRITER, 0, NULL);

-    }

+    gdbm_mode |= GDBM_WRITER;

+

+  temp_dbf = gdbm_open (pag_file, 0, gdbm_mode, mode, NULL);

   /* Did we successfully open the file? */

   if (temp_dbf == NULL)

diff -up gdbm-1.8.3/gdbm.3.dbmlock gdbm-1.8.3/gdbm.3

--- gdbm-1.8.3/gdbm.3.dbmlock	2011-01-03 15:59:15.684729255 +0100

+++ gdbm-1.8.3/gdbm.3	2011-01-03 16:17:49.957570637 +0100

@@ -543,7 +543,11 @@ you must link in the \fIgdbm_compat\fR l

 .sp

 	gcc -o prog proc.c -lgdbm -lgdbm_compat

-.SH BUGS

+.SH "ENVIRONMENT VARIABLES"

+\fINDBM_LOCK\fR - When the NDBM interface is used, the database file

+is locked by default. Locking might degrade performance when used on a

+NFS share. This environment variable can be set to false to tell GDBM

+not to lock the database file.

 .SH "SEE ALSO"

 dbm, ndbm