mail_pipe(1M)                                          mail_pipe(1M)


       NAME
             mail_pipe - invoke recipient command for incoming mail

       SYNOPSIS
             mail_pipe [-x debug_level] -r recipient -R path_to_sender -c content_type
                   -S subject

       DESCRIPTION
             When a new mail message arrives, the mail command first checks
             the recipient's forwarding file, /var/mail/:forward/user, to
             see if the message is to be forwarded elsewhere (to some other
             recipient or as the input to some command).  If the message is
             to be piped into a recipient-specified command, mail invokes
             mail_pipe to do some validation and then execute the command
             in the context of the recipient.

             Command-line arguments are:

             -x debug_level    Turn on debugging for this invocation.  See
                               the description of the -x option for the
                               mail command for details.

             -r recipient      The recipient's login id.

             -R path_to_sender The return address to the message's
                               originator.

             -c content_type   The value of the Content-Type: header line
                               in the message.

             -S subject        The value of the Subject: header line in the
                               message if present.

             mail_pipe is installed as a privileged process thus enabling
             itself to change it's user and group ids to that of the
             recipient as necessary.

             When invoked, mail_pipe performs the following steps (if a
             step fails, the exit code is noted as [N]):

                   Validate invocation arguments [1].

                   Verify that recipient name is < 14 characters long [2].





                           Copyright 1994 Novell, Inc.               Page 1

      mail_pipe(1M)                                          mail_pipe(1M)


                  Verify that the setuid flag for the recipient mailbox is
                  set and that the file is owned by the recipient [3].

                  Open /var/mail/recipient [4].

                  Verify that recipient's mailbox starts with the string
                  Forward to [5].

                  Find command string (prefaced with either `|' or `>|')
                  in the forwarding file [6].

                  Find entry for recipient in /etc/passwd [7].

                  Set gid to recipient's gid [8].

                  Set uid to recipient's uid [9].

                  Change current directory to recipient's login directory
                  [10].

                  Allocate space to hold newly exec'ed environment for
                  recipient command [11].

                  Parse the recipient command, performing any %keyletter
                  expansions required.  See the `Forwarding mail' section
                  of mail(1), for more information regarding %keyletter
                  substitutions [12].

                  Execute recipient command [13 if exec fails, otherwise
                  exit code from recipient command itself].

      ENVIRONMENT
            The command is executed with an environment of
            PATH=/usr/bin:/usr/lbin:, SHELL=/usr/bin/sh, LOGNAME, HOME,
            and TZ.  The value of LOGNAME and HOME are set according to
            the information found within /etc/passwd.  The value of TZ is
            passed through from the mail command.

      FILES
           /etc/passwd       to identify sender and locate recipients
           /var/mail/:forward/recipient
                              forwarding information for recipient
           /var/mail/recipient
                              incoming mail for recipient; that is, the
                              mail file



                          Copyright 1994 Novell, Inc.               Page 2

       mail_pipe(1M)                                          mail_pipe(1M)


            /tmp/MLDBG*       debug trace file
            /usr/lib/mail/mail_pipe
                               mail_pipe program

       REFERENCES
             mail(1), notify(1), vacation(1)










































                           Copyright 1994 Novell, Inc.               Page 3