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Message-Id: <4.3.1.2.20010227131655.015fd3c8@pop.ma.ultranet.com>
Date: Tue, 27 Feb 2001 13:24:26 -0500
To: "Alex Tang" <altitude AT airflash DOT com>, cygwin AT sources DOT redhat DOT com
From: "Larry Hall (RFK Partners, Inc)" <lhall AT rfk DOT com>
Subject: Re: dhcpd?
In-Reply-To: <3A9BE672.567EA62@airflash.com>
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At 12:40 PM 2/27/2001, Alex Tang wrote:
>Hi folks.
>
>I was wondering, has anyone tried porting the ISC dchpd (version 2) to
>cygwin?
>
>If someone has this working, please let me know and ignore the rest of
>this message. :-)
>
>I retrieved the dhcpd source from their CVS server (cvs co -r RELEASE_2
>DHCP from their server), and made some minor modifications to it to
>remove the winsock stuff and make it use "normal" networking code.  The
>compilation works fine (diffs are included below), however when the app
>is trying to do a rename(), it ALWSAYS gets a "permission denied".
>
>I am using the cygwin 1.1.8 DLL.
>
>The code chunk is included below:
>
>      void new_lease_file ()
>      {
>              char newfname [512];
>              char backfname [512];
>              TIME t;
>              int db_fd;
>
>              /* If we already have an open database, close it. */
>              if (db_file) {
>                      fclose (db_file);
>              }
>
>              /* Make a temporary lease file... */
>              GET_TIME (&t);
>              sprintf (newfname, "%s.%d", path_dhcpd_db, (int)t);
>              db_fd = open (newfname, O_WRONLY | O_TRUNC | O_CREAT, 0664);
>              if (db_fd < 0) {
>                      error ("Can't create new lease file: %m");
>              }
>              if ((db_file = fdopen (db_fd, "w")) == NULL) {
>                      error ("Can't fdopen new lease file!");
>              }
>
>              /* Write an introduction so people don't complain about time
>                 being off. */
>              fprintf (db_file, "# All times in this file are in UTC (GMT), not %s",
>                       "your local timezone.   This is\n");
>              fprintf (db_file, "# not a bug, so please don't ask about it.   %s",
>                       "There is no portable way to\n");
>              fprintf (db_file, "# store leases in the local timezone, so please %s",
>                       "don't request this as a\n");
>              fprintf (db_file, "# feature.   If this is inconvenient or %s",
>                       "confusing to you, we sincerely\n");
>              fprintf (db_file, "# apologize.   Seriously, though - don't ask.\n");
>              fprintf (db_file, "# The format of this file is documented in the %s",
>                       "dhcpd.leases(5) manual page.\n\n");
>
>              /* Write out all the leases that we know of... */
>              counting = 0;
>              write_leases ();
>
>              /* Get the old database out of the way... */
>              sprintf (backfname, "%s~", path_dhcpd_db);
>              if (unlink (backfname) < 0 && errno != ENOENT)
>                      error ("Can't remove old lease database backup %s: %m",
>                             backfname);
>              if (link (path_dhcpd_db, backfname) < 0)
>                      error ("Can't backup lease database %s to %s: %m",
>                             path_dhcpd_db, backfname);
>
>              /* Move in the new file... */
>              if (rename (newfname, path_dhcpd_db) < 0)
>                      error ("Can't install new lease database %s to %s: %m",
>                             newfname, path_dhcpd_db);
>
>              counting = 1;
>      }
>
>The last block (after "Move in the new file") always returns a -1 and
>the errno is EACCES.
>
>If i try to manually move the files from the shell, it works fine.  The
>permissions on all of the directories look fine (all directories are
>owned by me, and I'm running the dhcpd as me.)
>
>This is probably something butt-stupid that I'm doing.  however I can't
>see it.
>
>Does anyone have any insights?


Looks to me like newfname is open (db_fd).  Windows won't let you rename an
open file in general.


Larry Hall                              lhall AT rfk DOT com
RFK Partners, Inc.                      http://www.rfk.com
118 Washington Street                   (508) 893-9779 - RFK Office
Holliston, MA 01746                     (508) 893-9889 - FAX


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