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NAME
procmail - autonomous mail processor
SYNOPSIS
procmail [-ptoY] [-f fromwhom]
[parameter=value | rcfile] ...
procmail [-toY] [-f fromwhom] [-a argument] ...
-d recipient ...
procmail [-ptY] -m [parameter=value] ... rcfile
[argument] ...
procmail [-toY] [-a argument] -z
procmail -v
DESCRIPTION
For a quick start, see NOTES at the end.
Procmail should be invoked automatically over the .forward file mecha-
nism as soon as mail arrives. Alternatively, when installed by a sys-
tem administrator (and in the standard Red Hat Linux configuration), it
can be invoked from within the mailer immediately. When invoked, it
first sets some environment variables to default values, reads the mail
message from stdin until an EOF, separates the body from the header,
and then, if no command line arguments are present, it starts to look
for a file named $HOME/.procmailrc. According to the processing
recipes in this file, the mail message that just arrived gets dis-
tributed into the right folder (and more). If no rcfile is found, or
processing of the rcfile falls off the end, procmail will store the
mail in the default system mailbox.
If no rcfiles and no -p have been specified on the command line, proc-
mail will, prior to reading $HOME/.procmailrc, interpret commands from
/etc/procmailrc (if present). Care must be taken when creating
/etc/procmailrc, because, if circumstances permit, it will be executed
with root privileges (contrary to the $HOME/.procmailrc file of
course).
If running suid root or with root privileges, procmail will be able to
perform as a functionally enhanced, backwards compatible mail delivery
agent.
Procmail can also be used as a general purpose mail filter, i.e., pro-
visions have been made to enable procmail to be invoked in a special
sendmail rule.
The rcfile format is described in detail in the procmailrc(5) man page.
The weighted scoring technique is described in detail in the procmailsc(5)
man page.
Examples for rcfile recipes can be looked up in the procmailex(5) man
page.
Signals
TERMINATE Terminate prematurely and requeue the mail.
HANGUP Terminate prematurely and bounce the mail.
INTERRUPT Terminate prematurely and bounce the mail.
QUIT Terminate prematurely and silently lose the mail.
ALARM Force a timeout (see TIMEOUT).
USR1 Equivalent to a VERBOSE=off.
USR2 Equivalent to a VERBOSE=on.
OPTIONS
-v Procmail will print its version number, display its compile time
configuration and exit.
-p Preserve any old environment. Normally procmail clears the envi-
ronment upon startup, except for the value of TZ. However, in any
case: any default values will override any preexisting environment
variables, i.e., procmail will not pay any attention to any prede-
fined environment variables, it will happily overwrite them with
its own defaults. For the list of environment variables that
procmail will preset see the procmailrc(5) man page. If both -p
and -m are specified, the list of preset environment variables
shrinks to just: LOGNAME, HOME, SHELL, ORGMAIL and MAILDIR.
-t Make procmail fail softly, i.e., if procmail cannot deliver the
mail to any of the destinations you gave, the mail will not
bounce, but will return to the mailqueue. Another delivery-
attempt will be made at some time in the future.
-f fromwhom
Causes procmail to regenerate the leading `From ' line with
fromwhom as the sender (instead of -f one could use the alternate
and obsolete -r). If fromwhom consists merely of a single `-',
then procmail will only update the timestamp on the `From ' line
(if present, if not, it will generate a new one).
-o Instead of allowing anyone to generate `From ' lines, simply over-
ride the fakes.
-Y Assume traditional Berkeley mailbox format, ignore any Content-
Length: fields.
-a argument
This will set $1 to be equal to argument. Each succeeding -a
argument will set the next number variable ($2, $3, etc). It can
be used to pass meta information along to procmail. This is typi-
cally done by passing along the $@x information from the sendmail
mailer rule.
-d recipient ...
This turns on explicit delivery mode, delivery will be to the
local user recipient. This, of course, only is possible if proc-
mail has root privileges (or if procmail is already running with
the recipient's euid and egid). Procmail will setuid to the
intended recipients and delivers the mail as if it were invoked by
the recipient with no arguments (i.e., if no rcfile is found,
delivery is like ordinary mail). This option is incompatible with
-p.
-m Turns procmail into a general purpose mail filter. In this mode
one rcfile must be specified on the command line. After the
rcfile, procmail will accept an unlimited number of arguments. If
the rcfile is an absolute path starting with /etc/procmailrcs/
without backward references (i.e. the parent directory cannot be
mentioned) procmail will, only if no security violations are
found, take on the identity of the owner of the rcfile (or sym-
bolic link). For some advanced usage of this option you should
look in the EXAMPLES section below.
-z This turns on LMTP mode, wherein procmail acts as an RFC2033 LMTP
server. Delivery takes place in the same manner and under the
same restrictions as the delivery mode enabled with -d. This
option is incompatible with -p and -f.
ARGUMENTS
Any arguments containing an '=' are considered to be environment vari-
able assignments, they will all be evaluated after the default values
have been assigned and before the first rcfile is opened.
Any other arguments are presumed to be rcfile paths (either absolute,
or if they start with `./' relative to the current directory; any other
relative path is relative to $HOME, unless the -m option has been
given, in which case all relative paths are relative to the current
directory); procmail will start with the first one it finds on the com-
mand line. The following ones will only be parsed if the preceding
ones have a not matching HOST-directive entry, or in case they should
not exist.
If no rcfiles are specified, it looks for $HOME/.procmailrc. If not
even that can be found, processing will continue according to the
default settings of the environment variables and the ones specified on
the command line.
EXAMPLES
Examples for rcfile recipes can be looked up in the procmailex(5) man
page. A small sample rcfile can be found in the NOTES section below.
Skip the rest of this EXAMPLES section unless you are a system adminis-
trator who is vaguely familiar with sendmail.cf syntax.
The -m option is typically used when procmail is called from within a
rule in the sendmail.cf file. In order to be able to do this it is
convenient to create an extra `procmail' mailer in your sendmail.cf
file (in addition to the perhaps already present `local' mailer that
starts up procmail). To create such a `procmail' mailer I'd suggest
something like:
Mprocmail, P=/usr/bin/procmail, F=mSDFMhun, S=11, R=21,
A=procmail -m $h $g $u
This enables you to use rules like the following (most likely in rule-
set 0) to filter mail through the procmail mailer (please note the
leading tab to continue the rule, and the tab to separate the com-
ments):
R$*<@some.where>$*
$#procmail $@/etc/procmailrcs/some.rc $:$1@some.where.procmail$2
R$*<@$*.procmail>$*
$1<@$2>$3 Already filtered, map back
And /etc/procmailrcs/some.rc could be as simple as:
SENDER = "<$1>" # fix for empty sender addresses
SHIFT = 1 # remove it from $@
:0 # sink all junk mail
* ^Subject:.*junk
/dev/null
:0 w # pass along all other mail
! -oi -f "$SENDER" "$@"
Do watch out when sending mail from within the /etc/procmailrcs/some.rc
file, if you send mail to addresses which match the first rule again,
you could be creating an endless mail loop.
FILES
/etc/passwd to set the recipient's LOGNAME, HOME and SHELL
variable defaults
/var/spool/mail/$LOGNAME
system mailbox; both the system mailbox and the
immediate directory it is in will be created
every time procmail starts and either one is not
present
/etc/procmailrc initial global rcfile
/etc/procmailrcs/ special privileges path for rcfiles
$HOME/.procmailrc default rcfile
/var/spool/mail/$LOGNAME.lock
lockfile for the system mailbox (not automati-
cally used by procmail, unless $DEFAULT equals
/var/spool/mail/$LOGNAME and procmail is deliv-
ering to $DEFAULT)
/usr/sbin/sendmail default mail forwarder
_????`hostname` temporary `unique' zero-length files created by
procmail
SEE ALSO
procmailrc(5), procmailsc(5), procmailex(5),sh(1),csh(1),mail(1),
mailx(1), binmail(1), uucp(1), aliases(5), sendmail(8),egrep(1),
grep(1), biff(1), comsat(8),lockfile(1),formail(1), cron(1)
DIAGNOSTICS
Autoforwarding mailbox found
The system mailbox had its suid or sgid bit set,
procmail terminates with EX_NOUSER assuming that
this mailbox must not be delivered to.
Bad substitution of "x"
Not a valid environment variable name specified.
Closing brace unexpected
There was no corresponding opening brace (nest-
ing block).
Conflicting options Not all option combinations are useful
Conflicting x suppressed
Flag x is not compatible with some other flag on
this recipe.
Couldn't create "x" The system mailbox was missing and could
not/will not be created.
Couldn't create maildir part "x"
The maildir folder "x" is missing one or more
required subdirectories and procmail could not
create them.
Couldn't create or rename temp file "x"
An error occurred in the mechanics of deliver-
ing to the directory folder "x".
Couldn't determine implicit lockfile from "x"
There were no `>>' redirectors to be found, us-
ing simply `$LOCKEXT' as locallockfile.
Couldn't read "x" Procmail was unable to open an rcfile or it was
not a regular file, or procmail couldn't open an
MH directory to find the highest numbered file.
Couldn't unlock "x" Lockfile was already gone, or write permission
to the directory where the lockfile is has been
denied.
Deadlock attempted on "x"
The locallockfile specified on this recipe is
equal to a still active $LOCKFILE.
Denying special privileges for "x"
Procmail will not take on the identity that
comes with the rcfile because a security viola-
tion was found (e.g. -p or variable assignments
on the command line) or procmail had insuffi-
cient privileges to do so.
Descriptor "x" was not open
As procmail was started, stdin, stdout or stderr
was not connected (possibly an attempt to sub-
vert security)
Enforcing stricter permissions on "x"
The system mailbox of the recipient was found to
be unsecured, procmail secured it.
Error while writing to "x"
Nonexistent subdirectory, no write permission,
pipe died or disk full.
Exceeded LINEBUF Buffer overflow detected, LINEBUF was too small,
PROCMAIL_OVERFLOW has been set.
MAILDIR is not an absolute path
MAILDIR path too long
ORGMAIL is not an absolute path
ORGMAIL path too long
default rcfile is not an absolute path
default rcfile path too long
The specified item's full path, when expanded,
was longer than LINEBUF or didn't start with a
file separator.
Excessive output quenched from "x"
The program or filter "x" tried to produce too
much output for the current LINEBUF, the rest
was discarded and PROCMAIL_OVERFLOW has been
set.
Extraneous x ignored The action line or other flags on this recipe
makes flag x meaningless.
Failed forking "x" Process table is full (and NORESRETRY has been
exhausted).
Failed to execute "x" Program not in path, or not executable.
Forced unlock denied on "x"
No write permission in the directory where lock-
file "x" resides, or more than one procmail try-
ing to force a lock at exactly the same time.
Forcing lock on "x" Lockfile "x" is going to be removed by force be-
cause of a timeout (see also: LOCKTIMEOUT).
Incomplete recipe The start of a recipe was found, but it stranded
in an EOF.
Insufficient privileges
Procmail either needs root privileges, or must
have the right (e)uid and (e)gid to run in de-
livery mode. The mail will bounce.
Invalid regexp "x" The regular expression "x" contains errors (most
likely some missing or extraneous parens).
Kernel-lock failed While trying to use the kernel-supported locking
calls, one of them failed (usually indicates an
OS error), procmail ignores this error and pro-
ceeds.
Kernel-unlock failed See above.
Lock failure on "x" Can only occur if you specify some real weird
(and illegal) lockfilenames or if the lockfile
could not be created because of insufficient
permissions or nonexistent subdirectories.
Lost "x" Procmail tried to clone itself but could not
find back rcfile "x" (it either got removed or
it was a relative path and you changed directory
since procmail opened it last time).
Missing action The current recipe was found to be incomplete.
Missing closing brace A nesting block was started, but never finished.
Missing name The -f option needs an extra argument.
Missing argument You specified the -a option but forgot the argu-
ment.
Missing rcfile You specified the -m option, procmail expects
the name of an rcfile as argument.
Missing recipient You specified the -d option or called procmail
under a different name, it expects one or more
recipients as arguments.
No space left to finish writing "x"
The filesystem containing "x" does not have
enough free space to permit delivery of the mes-
sage to the file.
Out of memory The system is out of swap space (and NORESRETRY
has been exhausted).
Processing continued The unrecognised options on the command line are
ignored, proceeding as usual.
Program failure (nnn) of "x"
Program that was started by procmail returned
nnn instead of EXIT_SUCCESS (=0); if nnn is neg-
ative, then this is the signal the program died
on.
Quota exceeded while writing "x"
The filesize quota for the recipient on the
filesystem containing "x" does not permit deliv-
ering the message to the file.
Renaming bogus "x" into "x"
The system mailbox of the recipient was found to
be bogus, procmail performed evasive actions.
Rescue of unfiltered data succeeded/failed
A filter returned unsuccessfully, procmail tried
to get back the original text.
Skipped: "x" Couldn't do anything with "x" in the rcfile
(syntax error), ignoring it.
Suspicious rcfile "x" The owner of the rcfile was not the recipient or
root, the file was world writable, or the direc-
tory that contained it was world writable, or
this was the default rcfile ($HOME/.procmailrc)
and either it was group writable or the directo-
ry that contained it was group writable (the rc-
file was not used).
Terminating prematurely whilst waiting for ...
Procmail received a signal while it was waiting
for ...
Timeout, terminating "x"
Timeout has occurred on program or filter "x".
Timeout, was waiting for "x"
Timeout has occurred on program, filter or file
"x". If it was a program or filter, then it
didn't seem to be running anymore.
Truncated file to former size
The file could not be delivered to successfully,
so the file was truncated to its former size.
Truncating "x" and retrying lock
"x" does not seem to be a valid filename or the
file is not empty.
Unable to treat as directory "x"
Either the suffix on "x" would indicate that it
should be an MH or maildir folder, or it was
listed as an second folder into which to link,
but it already exists and is not a directory.
Unexpected EOL Missing closing quote, or trying to escape EOF.
Unknown user "x" The specified recipient does not have a corre-
sponding uid.
EXTENDED DIAGNOSTICS
Extended diagnostics can be turned on and off through setting the VER-
BOSE variable.
[pid] time & date Procmail's pid and a timestamp. Generated when-
ever procmail logs a diagnostic and at least a
second has elapsed since the last timestamp.
Acquiring kernel-lock Procmail now tries to kernel-lock the most re-
cently opened file (descriptor).
Assigning "x" Environment variable assignment.
Assuming identity of the recipient, VERBOSE=off
Dropping all privileges (if any), implicitly
turns off extended diagnostics.
Bypassed locking "x" The mail spool directory was not accessible to
procmail, it relied solely on kernel locks.
Executing "x" Starting program "x". If it is started by proc-
mail directly (without an intermediate shell),
procmail will show where it separated the argu-
ments by inserting commas.
HOST mismatched "x" This host was called "x", HOST contained some-
thing else.
Locking "x" Creating lockfile "x".
Linking to "x" Creating a hardlink between directory folders.
Match on "x" Condition matched.
Matched "x" Assigned "x" to MATCH.
No match on "x" Condition didn't match, recipe skipped.
Non-zero exitcode (nnn) by "x"
Program that was started by procmail as a condi-
tion or as the action of a recipe with the `W'
flag returned nnn instead of EXIT_SUCCESS (=0);
the usage indicates that this is not an entirely
unexpected condition.
Notified comsat: "$LOGNAME@offset:file"
Sent comsat/biff a notice that mail arrived for
user $LOGNAME at `offset' in `file'.
Opening "x" Opening file "x" for appending.
Rcfile: "x" Rcfile changed to "x".
Reiterating kernel-lock
While attempting several locking methods, one of
these failed. Procmail will reiterate until
they all succeed in rapid succession.
Score: added newtotal "x"
This condition scored `added' points, which re-
sulted in a `newtotal' score.
Unlocking "x" Removing lockfile "x" again.
WARNINGS
You should create a shell script that useslockfile(1) before invoking
your mail shell on any mailbox file other than the system mailbox (un-
less of course, your mail shell uses the same lockfiles (local or glob-
al) you specified in your rcfile).
In the unlikely event that you absolutely need to kill procmail before
it has finished, first try and use the regular kill command (i.e., not
kill -9, see the subsection Signals for suggestions), otherwise some
lockfiles might not get removed.
Beware when using the -t option, if procmail repeatedly is unable to
deliver the mail (e.g., due to an incorrect rcfile), the system
mailqueue could fill up. This could aggravate both the local postmas-
ter and other users.
The /etc/procmailrc file might be executed with root privileges, so be
very careful of what you put in it. SHELL will be equal to that of the
current recipient, so if procmail has to invoke the shell, you'd better
set it to some safe value first. See also: DROPPRIVS.
Keep in mind that ifchown(1) is permitted on files in /etc/procmail-
rcs/, that they can be chowned to root (or anyone else) by their cur-
rent owners. For maximum security, make sure this directory is exe-
cutable to root only.
Procmail is not the proper tool for sharing one mailbox among many
users, such as when you have one POP account for all mail to your do-
main. It can be done if you manage to configure your MTA to add some
headers with the envelope recipient data in order to tell Procmail who
a message is for, but this is usually not the right thing to do. Per-
haps you want to investigate if your MTA offers `virtual user tables',
or check out the `multidrop' facility of Fetchmail.
BUGS
After removing a lockfile by force, procmail waits $SUSPEND seconds be-
fore creating a new lockfile so that another process that decides to
remove the stale lockfile will not remove the newly created lock by
mistake.
Procmail uses the regular TERMINATE signal to terminate any runaway
filter, but it does not check if the filter responds to that signal and
it only sends it to the filter itself, not to any of the filter's chil-
dren.
A continued Content-Length: field is not handled correctly.
The embedded newlines in a continued header should be skipped when
matching instead of being treated as a single space as they are now.
MISCELLANEOUS
If there is an existing Content-Length: field in the header of the mail
and the -Y option is not specified, procmail will trim the field to re-
port the correct size. Procmail does not change the fieldwidth.
If there is no Content-Length: field or the -Y option has been speci-
fied and procmail appends to regular mailfolders, any lines in the body
of the message that look like postmarks are prepended with `>' (disarms
bogus mailheaders). The regular expression that is used to search for
these postmarks is:
`\nFrom '
If the destination name used in explicit delivery mode is not in
/etc/passwd, procmail will proceed as if explicit delivery mode was not
in effect. If not in explicit delivery mode and should the uid proc-
mail is running under, have no corresponding /etc/passwd entry, then
HOME will default to /, LOGNAME will default to #uid, SHELL will de-
fault to /bin/sh, and ORGMAIL will default to /tmp/dead.letter.
When in explicit delivery mode, procmail will generate a leading `From
' line if none is present. If one is already present procmail will
leave it intact. If procmail is not invoked with one of the following
user or group ids : root, daemon, uucp, mail, x400, network, list,
slist, lists or news, but still has to generate or accept a new `From '
line, it will generate an additional `>From ' line to help distinguish
fake mails.
For security reasons procmail will only use an absolute or $HOME-rela-
tive rcfile if it is owned by the recipient or root, not world
writable, and the directory it is contained in is not world writable.
The $HOME/.procmailrc file has the additional constraint of not being
group-writable or in a group-writable directory.
If /var/spool/mail/$LOGNAME is a bogus mailbox (i.e., does not belong
to the recipient, is unwritable, is a symbolic link or is a hard link),
procmail will upon startup try to rename it into a file starting with
`BOGUS.$LOGNAME.' and ending in an inode-sequence-code. If this turns
out to be impossible, ORGMAIL will have no initial value, and hence
will inhibit delivery without a proper rcfile.
If /var/spool/mail/$LOGNAME already is a valid mailbox, but has got too
loose permissions on it, procmail will correct this. To prevent proc-
mail from doing this make sure the u+x bit is set.
When delivering to directories, MH folders, or maildir folders, you
don't need to use lockfiles to prevent several concurrently running
procmail programs from messing up.
Delivering to MH folders is slightly more time consuming than deliver-
ing to normal directories or mailboxes, because procmail has to search
for the next available number (instead of having the filename immedi-
ately available).
On general failure procmail will return EX_CANTCREAT, unless option -t
is specified, in which case it will return EX_TEMPFAIL.
To make `egrepping' of headers more consistent, procmail concatenates
all continued header fields; but only internally. When delivering the
mail, line breaks will appear as before.
If procmail is called under a name not starting with `procmail' (e.g.,
if it is linked to another name and invoked as such), it comes up in
explicit delivery mode, and expects the recipients' names as command
line arguments (as if -d had been specified).
Comsat/biff notifications are done using udp. They are sent off once
when procmail generates the regular logfile entry. The notification
messages have the following extended format (or as close as you can get
when final delivery was not to a file):
$LOGNAME@offset_of_message_in_mailbox:absolute_path_to_mailbox
Whenever procmail itself opens a file to deliver to, it consistently
uses the following kernel locking strategies: fcntl(2).
Procmail is NFS-resistant and eight-bit clean.
NOTES
Calling up procmail with the -h or -? options will cause it to display
a command-line help and recipe flag quick-reference page.
There exists an excellent newbie FAQ about mailfilters (and procmail in
particular); it is maintained by Nancy McGough <nancym@ii.com> and can
be obtained by sending a mail to mail-server@rtfm.mit.edu with the fol-
lowing in the body:
send usenet/news.answers/mail/filtering-faq
Instead of using the system provided invocation of procmail when mail
arrives, you can control the invocation of procmail yourself. In this
case your $HOME/.forward (beware, it has to be world readable) file
should contain the line below. Be sure to include the single and dou-
ble quotes, and unless you know your site to be running smrsh (the
SendMail Restricted SHell), it must be an absolute path.
"|exec /usr/bin/procmail"
Procmail can also be invoked to postprocess an already filled system
mailbox. This can be useful if you don't want to or can't use a
$HOME/.forward file (in which case the following script could periodi-
cally be called from within cron(1), or whenever you start reading
mail):
#!/bin/sh
ORGMAIL=/var/spool/mail/$LOGNAME
if cd $HOME &&
test -s $ORGMAIL &&
lockfile -r0 -l1024 .newmail.lock 2>/dev/null
then
trap "rm -f .newmail.lock" 1 2 3 13 15
umask 077
lockfile -l1024 -ml
cat $ORGMAIL >>.newmail &&
cat /dev/null >$ORGMAIL
lockfile -mu
formail -s procmail <.newmail &&
rm -f .newmail
rm -f .newmail.lock
fi
exit 0
A sample small $HOME/.procmailrc:
PATH=/bin:/usr/bin:/usr/bin
MAILDIR=$HOME/Mail #you'd better make sure it exists
DEFAULT=$MAILDIR/mbox #completely optional
LOGFILE=$MAILDIR/from #recommended
:0:
* ^From.*berg
from_me
:0
* ^Subject:.*Flame
/dev/null
Other examples for rcfile recipes can be looked up in the procmailex(5)
man page.
SOURCE
This program is part of the procmail mail-processing-package (v3.22)
available at http://www.procmail.org/ or ftp.procmail.org in pub/proc-
mail/.
MAILINGLIST
There exists a mailinglist for questions relating to any program in the
procmail package:
<procmail-users@procmail.org>
for submitting questions/answers.
<procmail-users-request@procmail.org>
for subscription requests.
If you would like to stay informed about new versions and official
patches send a subscription request to
procmail-announce-request@procmail.org
(this is a readonly list).
AUTHORS
Stephen R. van den Berg
<srb@cuci.nl>
Philip A. Guenther
<guenther@sendmail.com>
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