V10/lbin/mailx/man/mail_pipe.1m

'\"macro stdmacro
.if n .pH g1a.mail_pipe %W% of %G%
.if \nX=0 .ds x} mail_pipe 1M "Essential Utilities" "\&"
.if \nX=1 .ds x} mail_pipe 1M "Essential Utilities"
.if \nX=2 .ds x} mail_pipe 1M "" "\&"
.if \nX=3 .ds x} mail_pipe "" "" "\&"
.nr X
.TH \*(x}
.SH NAME
\f4mail_pipe\f1 \- invoke recipient command for incoming mail
.SH SYNOPSIS
.PP
\f4mail_pipe\f1
[
\f4\-x\f1
.I debug_level
]
\f4\-r\f1
.I recipient
\f4\-R\f1
.I path_to_sender
\f4\-c\f1
.I content_type
\f4\-S\f1
.I subject
.SH DESCRIPTION
When a new mail message arrives,
the \f4mail\fP command first checks if the recipient's mailbox indicates
that 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,
\f4mail\fP invokes \f4mail_pipe\fP to do some validation and then execute
the command in the context of the recipient.
.PP
Command-line arguments are:
.PD 0
.TP 18
\f4\-x\fP \f2debug_level\fP
Turn on debugging for this invocation. See the description of the \f4\-x\fP
option for the \f4mail\fP command for details.
.TP
\f4\-r\fP \f2recipient\fP
The recipient's login id.
.TP
\f4\-R\fP \f2path_to_sender\fP
The return address to the message's originator.
.TP
\f4\-c\fP \f2content_type\fP
The value of the \f4Content-Type:\fP header line in the message.
.TP
\f4\-S\fP \f2subject\fP
The value of the \f4Subject:\fP header line in the message if present.
.PD
.PP
\f4mail_pipe\fP is installed as a setuid-to-root process,
thus enabling itself to change it's user and group ids to that of the
recipient as necessary.
.PP
When invoked,
\f4mail_pipe\fP performs the following steps (if a step fails, the exit
code is noted as [\f2N\f1]):
.PD 0
.TP 3
\-
Validate invocation arguments [\f41\f1].
.TP 3
\-
Verify that recipient name is \(<= 14 characters long [\f42\f1].
.TP 3
\-
Verify that the setgid flag for the recipient mailbox is set [\f43\f1].
.TP 3
\-
Open \f4/var/mail/\fP\f2recipient\fP [\f44\f1].
.TP 3
\-
Verify that recipient's mailbox starts with the string \f4Forward to\fP [\f45\f1].
.TP 3
\-
Find pipe symbol indicating start of command string in recipient
mailbox [\f46\f1].
.TP 3
\-
Find entry for recipient in \f4/etc/passwd\f1 [\f47\f1].
.TP 3
\-
Set gid to recipient's gid [\f48\f1].
.TP 3
\-
Set uid to recipient's uid [\f49\f1].
.TP 3
\-
Change current directory to recipient's login directory [\f410\f1].
.TP 3
\-
Allocate space to hold newly \f4exec\f1'ed environment for
recipient command [\f411\f1].
.TP 3
\-
Parse the recipient command, performing any \f4%\f2keyword\f1 expansions required.
See the `Forwarding mail' section of \f4mail\fP(1), for more information
regarding \f4%\f2keyword\f1 substitutions [\f412\f1].
.TP 3
\-
Execute recipient command [\f413\f1 if \f4exec\f1 fails,
otherwise exit code from recipient command itself].
.PD
.SH FILES
.PD 0
.TP 20
\f4/etc/passwd\fP
to identify sender and locate recipients
.TP
\f4/var/mail/\f2recipient\f1
incoming mail for \f2recipient\fP;
that is, the mail file
.TP
\f4/tmp/MLDBG\(**\fP
debug trace file
.TP
\f4/usr/lib/mail/mail_pipe\fP
mail_pipe program
.PD
.SH SEE ALSO
\f4mail\fP(1),
\f4notify\fP(1),
\f4vacation\fP(1)