General-Purpose Mail Filter
MailfromdCommand Line Syntax
mailfromd binary is started from the command line
using the following syntax (brackets indicate optional parts):
$ mailfromd [options] [asgn] [script]
The meaning of each invocation part is described in the table below:
The command line options (see options).
Sendmail macro assignments. These are currently meaningful only with the --test option (see test mode), but this may change in the future. Each assignment has the form:
where var is the name of a Sendmail macro and value is the value to be assigned to it.
The file name of the filter script, if other than the default one.
Run in daemon mode (default).
Load the script named in the command line and execute the function named start, or ‘main’, if start is not given. See Run Mode, for a detailed description of this feature.
Show compilation defaults. See Databases.
Run in test mode. See Testing Filter Scripts. Default state is ‘envfrom’. This option implies --stderr (see --stderr).
Set socket for the default callout server. This is mainly useful together with the --mtasim option.
Stay in foreground. When given this option,
not disconnect itself from the controlling terminal and will run in
Retain the group name when switching to user privileges. See Starting and Stopping.
This option complements the
group configuration statement
Add the directory dir to the list of directories to be searched
for header files. This will affect the functioning of
statement. See include, for a discussion of file inclusion.
Set the URL of the mailer to use. See Mail Sending Functions.
This option is reserved for use by
mtasim (see mtasim).
Set optimization level for code generator. Two levels are implemented: ‘0’, meaning no optimization, and ‘1’, meaning full optimization.
Set communication socket. Overrides the
statement, which you are advised to use instead (see listen).
Set pidfile name. Overrides the
statement, which you are advised to use instead (see pidfile).
Read relayed domains from file. Overrides the
relayed-domain-file configuration statement (see relayed-domain-file), which you are advised to use instead.
See Avoiding Verification Loops, and the description of
relayed function (see relayed) for more information.
Read resolver settings from file, instead of the default /etc/resolv.conf.
Set new program state directory. See Local state directory, for
the description of this directory and its purposes. This option
overrides the settings of
state-directory configuration statement,
described in state-directory.
Set source address for TCP connections. Overrides the ‘source-ip’ configuration statement, which you are advised to use instead (see source-ip).
Switch to this user privileges after startup. Overrides the
configuration file statement, which you are advised to use instead
(see user). Default user is ‘mail’.
Assign value to the global variable var. The variable must be declared in your startup script. See overriding initial values, for a detailed discussion of this option.
Following command line options control the preprocessor feature. See Preprocessor, for a detailed discussion of these.
Do not run the preprocessor.
Use command as the external preprocessor instead of the default
Define a preprocessor symbol name to have a value value.
Undefine the preprocessor symbol name.
Stop after the preprocessing stage; do not run the compiler proper. The output is in the form of preprocessed source code, which is sent to the standard output.
See time interval specification, for information on interval format.
Set MTA connection timeout. Overrides
statement in the
mailfromd configuration file, which you are
advised to use instead (see milter-timeout).
Mention column number in error messages. See location-column. Use --no-location-column to disable
Set debugging level. See Logging and Debugging.
Parse and compile the script file and dump the disassembled listing of the produced code to the terminal. See Logging and Debugging.
Enable debugging the script file parser. While parsing the file, the detailed dump of the parser states and tokens seen will be output.
Enable debugging the lexical analyzer. While parsing the script file, the detailed dump of the lexer states and matched rules will be output.
Show Sendmail macros used in the script file. The macro names are displayed as comma-separated lists, grouped by handler names. See Sendmail, for a detailed description of this option and its usage.
Parse and compile the script file and dump the parse tree in a printable form to the terminal.
Print a cross-reference of variables used in the filter script. See Testing Filter Scripts.
Stop after the preprocessing stage; do not run the compiler proper. The output is in the form of preprocessed source code, which is sent to the standard output. See Preprocessor.
Check script file syntax and exit. If the file is OK, return 0 to the shell, otherwise print appropriate messages to stderr and exit with code 78 (‘configuration error’).
Do not fork sub-processes to serve requests. This option is meant to
assist in debugging
mailfromd. Don’t use it for anything
else but for debugging, as it terribly degrades performance!
Add MFL stack trace information to runtime error output.
stack-trace configuration statement. Use the
--no-stack-trace to disable trace information.
See tracing runtime errors, for more information on this feature.
Set desired logging level for
(see Gacopyz). There are five logging levels. The following
table lists them in order of decreasing priority:
Log fatal errors.
Log error messages.
Log warning messages.
Log informational messages. In particular, this enables printing messages on each subprocess startup and termination, which look like that:
Apr 28 09:00:11 host mailfromd: connect from 192.168.10.1:50398 Apr 28 09:00:11 host mailfromd: finishing connection
This level can be useful for debugging your scripts.
Log debugging information.
Log Milter protocol interactions. This level prints huge amounts of information, in particular it displays dumps of each Milter packet sent and received.
Although it is possible to set these levels independently of each
other, it is seldom practical. Therefore, the option
--gacopyz-log=level enables all logging levels from
level up. For example, --gacopyz-log=warn enables
log levels ‘warn’, ‘err’ and ‘fatal’. It is the
default. If you need to trace each subprocess startup and shutdown,
set --gacopyz-log=info. Setting the logging level to
‘proto’ can be needed only for
Gacopyz developers, to
debug the protocol.
See Testing Filter Scripts.
Set logger mechanism (mech is one of ‘stderr’, ‘syslog’, ‘syslog:async’). See Logging and Debugging.
Output logs to syslog facility.
Tag syslog entries with the given string, instead of the program name.
Include C source information in debugging messages. This is
similar to setting
line-info yes in the
configuration block (see line-info in GNU Mailutils Manual).
The --no-source-info can be used to cancel the effect of the
line-info yes configuration statement.
You do not need this option, unless you are developing or debugging
Synonym for --lint.
Enable or disable action tracing. If --trace is given,
mailfromd will log all executed actions. See Logging and Debugging.
Enable program instruction tracing. With this option
mailfromd will log execution of every instruction in the
compiled filter program. The optional arguments allows to specify a
comma-separated list of source code modules for which the tracing is
to be enabled, for example
tracing for functions from modules bi_io.c and bi_db.c
(notice, that you need not give file suffixes in string).
This option is useful for debugging
mailfromd, but is not
advised to use otherwise, since it is very time-costly.
Enable or disable transcript of the SMTP sessions to the log channel. See Logging and Debugging.
Selects default syslog mechanism for diagnostic output.
Directs all logging to standard output. Similar to --logger=stderr.
Same as --dump-xref. See Logging and Debugging.
Give a short help summary.
Give a short usage message.
Print program version.
Right after startup, when
mailfromd has done the
operations that require root privileges, it switches to the privileges
of the user it is configured to run as (see default user privileges) or
the one given in its configuration file (see user). During
this process it will drop all supplementary groups and switch to the
principal group of that user.
Such limited privileges of the daemon can cause difficulties if your
filter script needs to access some files (e.g.
databases) that are not accessible to that user and group. For
example, the following fragment using
if dbmap("/etc/mail/aliases.db", $f, 1) … fi
will normally fail, because /etc/mail/aliases.db is readable only to the root and members of the group ‘smmsp’.
In such situations you need to instruct
retain the privileges of one or several supplementary groups when
switching to the user privileges. This is done using
statement in the
mailfromd configuration file
(see group). In example above, you need to use the following
(The same effect can be achieved with --group command line option: mailfromd --group=smmsp).
To stop a running instance of
mailfromd use one of the
All three signals have the same effect: the program cancels handling any
pending requests, uninitializes the communication socket (if it is a
UNIX socket, the program unlinks it) and exits.
To restart the running
mailfromd instance, send it
SIGHUP. For restart to be possible, two conditions must be
mailfromd must be invoked with the full file name, and the
configuration file name must be full as well. If either of them is not
mailfromd displays a similar warning message:
warning: script file is given without full file name warning: restart (SIGHUP) will not work
warning: mailfromd started without full file name warning: restart (SIGHUP) will not work
The reaction of
SIGHUP in this case is
the same as on the three signals described previously, i.e. cleanup
and exit immediately.
The PID of the master instance of
kept on the pidfile, which is named mailfromd.pid and is
located in the program state directory. Assuming the default
location of the latter, the following command will stop the running
instance of the daemon:
kill -TERM `head -n1 /usr/local/var/mailfromd/mailfromd.pid`
The default pidfile location is shown in the output of
--show-defaults (see Databases), and can be changed at run time using
pidfile statement (see pidfile).
To facilitate the use of
mailfromd, it is shipped with a shell
script that can be used to launch it on system startup and shut it
down when the system goes down. The script, called
rc.mailfromd, is located in the directory /etc of the
distribution. It takes a single argument, specifying the action that
should be taken:
Start the program.
Shut down the program
Reload the program, by sending it
Shut down the program and start it again.
Display program status. It displays the PID of the master process and its command line, for example:
$ /etc/rc.d/rc.mailfromd status mailformd appears to be running at 26030 26030 /usr/local/sbin/mailfromd --group smmsp
If the second line is not displayed, this most probably mean that there is a ‘stale’ pidfile, i.e. the one left though the program is not running.
An empty rc.mailfromd status output means that
mailfromd is not running.
Check the script file syntax, report any errors found and exit. If file is given it is checked instead of the default one.
Parse the script file (or file, if it is given, extract the names of Sendmail macros it uses and generate corresponding export statements usable in the Sendmail configuration file. By default, mc statements are generated. If -c (--cf) is given, the statements for sendmail.cf are output. See the next chapter for the detailed description of this mode.
You can pass any additional arguments to
ARGS variable near line 22.
The script is not installed by default. You will have to copy it to the directory where your system start-up scripts reside and ensure it is called during the system startup and shut down. The exact instructions on how to do so depend on the operating system you use and are beyond the scope of this manual.
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