7 Configuring mailfromd

Upon startup, mailfromd checks if the file /etc/mailfromd.conf exists.²⁹ If it does, the program attempts to retrieve its configuration settings from that file.

The mailfromd.conf file must be written in the GNU mailutils configuration format, as described in Configuration File Syntax in GNU Mailutils Manual. This format can be summarized as follows:

Comments

Inline comments begin with ‘//’ or ‘#’ and end at the end of the line. Multiline comments are delimited by ‘/*’ and ‘*/’. Multiline comments cannot be nested, but can contain inline comment markers.

Empty lines and whitespace

Empty lines are ignored. Whitespace characters (i.e. horizontal, vertical space, and newline) are ignored, except as they serve to separate tokens.

Statements

A statement consists of a keyword and a value, separated by whitespace. Statements terminate with a semicolon. E.g.

pidfile /var/run/mailfromd.pid;

Block statements

A block statement consists of a keyword and a list of statements enclosed in ‘{’ and ‘}’ characters. Optional label can appear between the keyword and opening curly brace. E.g.:

logging {
  syslog on;
  facility mail;
}

Block statement is not required to terminate with a semicolon, although it is allowed to.

File Inclusion

The include statement causes inclusion of the file listed as its value:

include /usr/share/mailfromd/config.inc;

The mailfromd.conf file is used by all programs that form the ‘mailfromd’ package, i.e. mailfromd, calloutd, mfdbtool, and pmult. Since the sets of statements understood by each of them differ, special syntactic means are provided to separate program-specific configurations from each other.

First of all, if the argument to include is a directory, then the program will search that directory for a file with the same name as the base name of the program itself. If found, this file will be loaded after finishing parsing the mailfromd.conf file. Otherwise, this statement is ignored.

Secondly, the special block statement program tag is processed only if tag matches the base name of the program being run. Again, it is processed after the main mailfromd.conf file.

Thus, if you need to provide configuration for the calloutd component, there are two ways of doing so. First, you can place it to a file named calloutd placed in a separate directory (say, /etc/mailfromd.d), and use the name of that directory in a include statement in the main configuration file:

include /etc/mailfromd.d;

Secondly, you can use the program statement as follows:

program calloutd {
  ...
}