[PATCH] winbindd_idmap.c [Re: idmap recovery tool}

[Michael Steffens]

Hi again,

this patch provides the idmap logging required to recover
winbindd_idmap.tdb any time. Rather than to the state of
the last dump/backup, with all new mappings since then being
lost.

It's not entirely what I had in mind, yet. The informational
third field with the plain text NT name is missing, as this
is not directly available inside get_id_from_rid().

I didn't want to change too much at once, so let's put up
without for now...

The log file winbindd_idmap.log is presently at the same
location as winbindd_idmap.tdb. Not ideal, it should be a
configurable parameter of its own, such that an administrator
can choose to keep this log in a different filesystem for
better redundancy. But again, let's put up... :-)

Cheers!
Michael
-------------- next part --------------
Index: source/nsswitch/winbindd_idmap.c
===================================================================
RCS file: /cvsroot/samba/source/nsswitch/winbindd_idmap.c,v
retrieving revision 1.3.4.7
diff -u -w -r1.3.4.7 winbindd_idmap.c
--- source/nsswitch/winbindd_idmap.c	19 Jan 2002 20:16:40 -0000	1.3.4.7
+++ source/nsswitch/winbindd_idmap.c	12 Feb 2002 12:01:44 -0000
@@ -66,6 +66,30 @@
     return True;
 }
 
+/* Log id mapping. Reopen log file for every entry, because information
+   would be lost when someone unlinks the file while winbindd has it open */
+
+static BOOL log_idmap(TDB_DATA id, TDB_DATA sid)
+{
+    FILE *logfile;
+
+    if ((logfile = fopen(lock_path("winbindd_idmap.log"), "a")) == NULL) {
+        DEBUG(1, ("cannot open %s : %s\n",
+                  lock_path("winbindd_idmap.log"), strerror(errno)));
+        return False;
+    }
+    
+    if (fprintf(logfile, "%s:%s\n", id.dptr, sid.dptr) < 0) {
+        DEBUG(1, ("cannot write %s:%s to %s : %s\n", id.dptr, sid.dptr,
+                  lock_path("winbindd_idmap.log"), strerror(errno)));
+        fclose(logfile);
+        return False;
+    }
+
+    fclose(logfile);
+    return True;
+}
+
 /* Get an id from a rid */
 
 static BOOL get_id_from_rid(char *domain_name, uint32 rid, uid_t *id,
@@ -121,10 +145,14 @@
             data.dptr = keystr2;
             data.dsize = strlen(keystr2) + 1;
 
+            /* have mapping depend on successful log in order to avoid
+               data loss for recovery */
+
+            if (log_idmap(data, key)) {
             tdb_store(idmap_tdb, key, data, TDB_REPLACE);
             tdb_store(idmap_tdb, data, key, TDB_REPLACE);
-
             result = True;
+	    }
         }
     }