Update.

	* nss/nss_db/db-XXX.c: Move internal_setent and internal_endent
	functions from here...
	* nss/db-alias.c: ...and here...
	* nss/db-netgrp.c: ...and here...
	* nss/nss_db/db-open.c: ...to here.  New file.
	* nss/nss_db/dummy-db.h: New file.
	* nss/nss_db/nss_db.h: New file.
	* nss/Depend: Depend in dlfcn, not db2.
	* nss/Makefile (libnss_db-routines): Add db-open.
	(distribute): Add nss_db.h dummy-db.h.
	(libnss_db.so): Replace libdb dependency by $(libdl).
	Based on a patch by Zack Weinberg.

1 files changed, 229 insertions, 0 deletions

diff --git a/nss/nss_db/db-open.c b/nss/nss_db/db-open.c
new file mode 100644
index 0000000000..2d96ffdd1b
--- /dev/null
+++ b/nss/nss_db/db-open.c
@@ -0,0 +1,229 @@
+/* Common database open/close routines for nss_db.
+   Copyright (C) 1999, 2000 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Library General Public License as
+   published by the Free Software Foundation; either version 2 of the
+   License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Library General Public License for more details.
+
+   You should have received a copy of the GNU Library General Public
+   License along with the GNU C Library; see the file COPYING.LIB.  If not,
+   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.  */
+
+#include <fcntl.h>
+#include <dlfcn.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <bits/libc-lock.h>
+
+#include "dummy-db.h"
+#include "nsswitch.h"
+#include "nss_db.h"
+
+/* This file contains the functions used to open and close the databases
+   read by the rest of libnss_db.  They are not thread safe; the caller
+   must handle locking.
+
+   We dynamically load the database library, so that it does not have
+   to be present when glibc is compiled.  Once loaded, libdb is never
+   unloaded again unless this library is unloaded (from the free_mem
+   routine in nsswitch.c) - we catch the unload by providing a shlib
+   destructor.  (XXX Does it work?)  */
+
+static void *libdb_handle;
+enum {
+  nodb,
+  db24,
+  db27
+} libdb_version;
+static int (*libdb_db_open) (const char *, int,
+			     uint32_t, int, void *, void *, void **);
+
+/* Locks the static variables in this file.  */
+__libc_lock_define_initialized (static, lock)
+
+/* Dynamically load the database library.
+   We try libdb2.so.3, maybe others in the future.  */
+static int
+load_db (void)
+{
+  static const char *libnames[] = { "libdb.so.3" };
+  int x;
+
+  for(x = 0; x < 1; ++x)
+    {
+      libdb_handle = dlopen (libnames[x], RTLD_LAZY);
+      if (libdb_handle == NULL)
+	continue;
+
+      libdb_db_open = dlsym (libdb_handle, "db_open");
+      if (libdb_db_open)
+	{
+	  /* Alright, we got a library.  Now find out which version it is.  */
+	  const char *(*db_version) (int *, int *, int *);
+
+	  db_version = dlsym (libdb_handle, "db_version");
+	  if (db_version != NULL)
+	    {
+	      /* Call the function and get the information.  */
+	      int major, minor, subminor;
+
+	      DL_CALL_FCT (db_version, (&major, &minor, &subminor));
+	      if (major == 2)
+		{
+		  /* We currently cannot handle other versions than the
+		     2.x series.  */
+		  if (minor < 6 || (minor == 6 && subminor < 4))
+		    libdb_version = db24;
+		  else
+		    libdb_version = db27;
+		}
+	    }
+
+	  if (libdb_version != nodb)
+	    return 0;
+	}
+
+      dlclose (libdb_handle);
+    }
+
+  (void) dlerror ();
+  return 1;
+}
+
+
+/* Make sure we don't use the library anymore once we are shutting down.  */
+static void __attribute__ ((destructor))
+unload_db (void)
+{
+  if (libdb_handle != NULL)
+    {
+      libdb_db_open = NULL;
+      libdb_version = nodb;
+      dlclose (libdb_handle);
+    }
+}
+
+
+enum nss_status
+internal_setent (const char *file, NSS_DB **dbp)
+{
+  enum nss_status status = NSS_STATUS_SUCCESS;
+  int err;
+  void *db;
+
+  if (*dbp == NULL)
+    {
+      if (libdb_db_open == NULL)
+	{
+	  __libc_lock_lock (lock);
+
+	  err = load_db ();
+
+	  __libc_lock_unlock (lock);
+
+	  if (err != 0)
+	    return NSS_STATUS_UNAVAIL;
+	}
+
+      /* Open the database.  Fortunately this interface seems to be the
+	 same for all supported versions.  */
+      err = DL_CALL_FCT (libdb_db_open,
+			 (file, DB_BTREE, DB_RDONLY, 0, NULL, NULL, &db));
+
+      /* Construct the object we pass up.  */
+      *dbp = (NSS_DB *) malloc (sizeof (NSS_DB));
+      if (*dbp != NULL)
+	{
+	  (*dbp)->db = db;
+
+	  /* The functions are at different positions for the different
+	     versions.  Sigh.  */
+	  switch (libdb_version)
+	    {
+	    case db24:
+	      (*dbp)->close =
+		(int (*) (void *, uint32_t)) ((struct db24 *) db)->close;
+	      (*dbp)->fd =
+		(int (*) (void *, int *)) ((struct db24 *) db)->fd;
+	      (*dbp)->get =
+		(int (*) (void *, void *, void *, void *, uint32_t))
+		((struct db24 *) db)->get;
+	      break;
+	    case db27:
+	      (*dbp)->close =
+		(int (*) (void *, uint32_t)) ((struct db27 *) db)->close;
+	      (*dbp)->fd =
+		(int (*) (void *, int *)) ((struct db27 *) db)->fd;
+	      (*dbp)->get =
+		(int (*) (void *, void *, void *, void *, uint32_t))
+		((struct db27 *) db)->get;
+	      break;
+	    default:
+	      abort ();
+	    }
+	}
+
+      if (err != 0)
+	{
+	  __set_errno (err);
+	  *dbp = NULL;
+	  status = err == EAGAIN ? NSS_STATUS_TRYAGAIN : NSS_STATUS_UNAVAIL;
+	}
+      else
+	{
+	  /* We have to make sure the file is `closed on exec'.  */
+	  int fd;
+	  int result;
+
+	  err = DL_CALL_FCT ((*dbp)->fd, (db, &fd));
+	  if (err != 0)
+	    {
+	      __set_errno (err);
+	      result = -1;
+	    }
+	  else
+	    {
+	      int flags = result = fcntl (fd, F_GETFD, 0);
+
+	      if (result >= 0)
+		{
+		  flags |= FD_CLOEXEC;
+		  result = fcntl (fd, F_SETFD, flags);
+		}
+	    }
+	  if (result < 0)
+	    {
+	      /* Something went wrong.  Close the stream and return a
+		 failure.  */
+	      DL_CALL_FCT ((*dbp)->close, (db, 0));
+	      status = NSS_STATUS_UNAVAIL;
+	    }
+
+	  if (result < 0)
+	    *dbp = NULL;
+	}
+    }
+
+  return status;
+}
+
+
+/* Close the database file.  */
+void
+internal_endent (NSS_DB **dbp)
+{
+  NSS_DB *db = *dbp;
+  if (db != NULL)
+    {
+      DL_CALL_FCT (db->close, (db->db, 0));
+      *dbp = NULL;
+    }
+}