1SLOCAL(1) [nmh-1.2-20070115cvs] SLOCAL(1)
2
6 slocal - asynchronously filter and deliver new mail
7
9 /usr/libexec/nmh/slocal [address info sender] [-addr address] [-info
10 data] [-sender sender] [-user username] [-mailbox mbox] [-file
11 file] [-maildelivery deliveryfile] [-verbose | -noverbose] [-sup‐
12 pressdup | -nosuppressdup] [-debug] [-version] [-help]
13
15 Slocal is a program designed to allow you to have your inbound mail
16 processed according to a complex set of selection criteria. You do not
17 normally invoke slocal yourself, rather slocal is invoked on your
18 behalf by your system's Message Transfer Agent (such as sendmail) when
19 the message arrives.
20 The message selection criteria used by slocal is specified in the file
22 “.maildelivery” in the user's home directory. You can specify an
23 alternate file with the -maildelivery file option. The syntax of this
24 file is specified below.
25 The message delivery address and message sender are determined from the
27 Message Transfer Agent envelope information, if possible. Under send‐
28 mail, the sender will obtained from the UUCP “From:” line, if present.
29 The user may override these values with command line arguments, or
30 arguments to the -addr and -sender switches.
31 The message is normally read from the standard input. The -file switch
33 sets the name of the file from which the message should be read,
34 instead of reading stdin. This is useful when debugging a “.maildeliv‐
35 ery” file.
36 The -user switch tells slocal the name of the user for whom it is
38 delivering mail. The -mailbox switch tells slocal the name of the
39 user's maildrop file.
40 slocal is able to detect and suppress duplicate messages. To enable
42 this, use the option -suppressdup. slocal will keep a database con‐
43 taining the Message-ID's of incoming messages, in order to detect
44 duplicates. Depending on your configuration, this database will be in
45 either ndbm or Berkeley db format.
46 The -info switch may be used to pass an arbitrary argument to sub-pro‐
48 cesses which slocal may invoke on your behalf.
49 The -verbose switch causes slocal to give information on stdout about
51 its progress. The -debug switch produces more verbose debugging output
52 on stderr. These flags are useful when creating and debugging your
53 “.maildelivery” file, as they allow you to see the decisions and
54 actions that slocal is taking, as well as check for syntax errors in
55 your “.maildelivery” file.
56 Message Transfer Agents
59 Most modern MTAs including sendmail, postfix and exim support a .for‐
60 ward file for directing incoming mail. You should include the line
61 “| /usr/libexec/nmh/slocal -user username”
63 in your .forward file in your home directory. This will cause your MTA
65 to invoke slocal on your behalf when a message arrives.
66 The Maildelivery File
69 The “.maildelivery” file controls how slocal filters and delivers
70 incoming mail. Each line of this file consists of five fields, sepa‐
71 rated by white-space or comma. Since double-quotes are honored, these
72 characters may be included in a single argument by enclosing the entire
73 argument in double-quotes. A double-quote can be included by preceding
74 it with a backslash. Lines beginning with `#' and blank lines are
75 ignored.
76 The format of each line in the “.maildelivery” file is:
78 header pattern action result string
80 header:
82 The name of a header field (such as To, Cc, or From) that is to
83 be searched for a pattern. This is any field in the headers of
84 the message that might be present.
85 The following special fields are also defined:
87 source the out-of-band sender information
89 addr the address that was used to cause delivery to the
91 recipient
92 default this matches only if the message hasn't been delivered
94 yet
95 * this always matches
97 pattern:
99 The sequence of characters to match in the specified header field.
100 Matching is case-insensitive, but does not use regular expres‐
101 sions.
102 action:
104 The action to take to deliver the message. When a message is
105 delivered, a “Delivery-Date: date” header is added which indicates
106 the date and time that message was delivered.
107 destroy This action always succeeds. file, mbox, or > Append
109 the message to the file named by string. The message
110 is appended to the file in mbox (uucp) format. This
111 is the format used by most other mail clients (such
112 as mailx, elm). If the message can be appended to
113 the file, then this action succeeds.
114 mmdf Identical to file, but always appends the message
116 using the MMDF mailbox format.
117 pipe or | Pipe the message as the standard input to the command
119 named by string, using the Bourne shell sh to inter‐
120 pret the string. Prior to giving the string to the
121 shell, it is expanded with the following built-in
122 variables:
123 $(sender) the out-of-band sender information
125 $(address) the address that was used to cause
127 delivery to the recipient
128 $(size) the size of the message in bytes
130 $(reply-to) either the “Reply-To:” or “From:” field
132 of the message
133 $(info) the out-of-band information specified
135 qpipe or ^ Similar to pipe, but executes the command directly,
137 after built-in variable expansion, without assistance
138 from the shell. This action can be used to avoid
139 quoting special characters which your shell might
140 interpret.
141 folder or + Store the message in the nmh folder named by string.
143 Currently this is handled by piping the message to
144 the nmh program rcvstore, although this may change in
145 the future.
146 result:
148 Indicates how the action should be performed:
149 A Perform the action. If the action succeeds, then the message
151 is considered delivered.
152 R Perform the action. Regardless of the outcome of the action,
154 the message is not considered delivered.
155 ? Perform the action only if the message has not been delivered.
157 If the action succeeds, then the message is considered deliv‐
158 ered.
159 N Perform the action only if the message has not been delivered
161 and the previous action succeeded. If this action succeeds,
162 then the message is considered delivered.
163 The delivery file is always read completely, so that several
165 matches can be made and several actions can be taken.
166 Security of Delivery Files
169 In order to prevent security problems, the “.maildelivery” file must be
170 owned either by the user or by root, and must be writable only by the
171 owner. If this is not the case, the file is not read.
172 If the “.maildelivery” file cannot be found, or does not perform an
174 action which delivers the message, then slocal will check for a global
175 delivery file at /etc/nmh/maildelivery. This file is read according to
176 the same rules. This file must be owned by the root and must be
177 writable only by the root.
178 If a global delivery file cannot be found or does not perform an action
180 which delivers the message, then standard delivery to the user's mail‐
181 drop is performed.
182 Example Delivery File
185 To summarize, here's an example delivery file:
186 #
188 # .maildelivery file for nmh's slocal
189 #
190 # Blank lines and lines beginning with a '#' are ignored
191 #
192 # FIELD PATTERN ACTION RESULT STRING
193 #
194 # File mail with foobar in the “To:” line into file foobar.log
196 To foobar file A foobar.log
197 # Pipe messages from coleman to the program message-archive
199 From coleman pipe A /bin/message-archive
200 # Anything to the “nmh-workers” mailing list is put in
202 # its own folder, if not filed already
203 To nmh-workers folder ? nmh-workers
204 # Anything with Unix in the subject is put into
206 # the file unix-mail
207 Subject unix file A unix-mail
208 # I don't want to read mail from Steve, so destroy it
210 From steve destroy A -
211 # Put anything not matched yet into mailbox
213 default - file ? mailbox
214 # always run rcvtty
216 * - pipe R /usr/libexec/nmh/rcvtty
217 Sub-process environment
220 When a process is invoked, its environment is: the user/group-ids are
221 set to recipient's ids; the working directory is the recipient's home
222 directory; the umask is 0077; the process has no /dev/tty; the standard
223 input is set to the message; the standard output and diagnostic output
224 are set to /dev/null; all other file-descriptors are closed; the envi‐
225 ronment variables $USER, $HOME, $SHELL are set appropriately, and no
226 other environment variables exist.
227 The process is given a certain amount of time to execute. If the
229 process does not exit within this limit, the process will be terminated
230 with extreme prejudice. The amount of time is calculated as ((size /
231 60) + 300) seconds, where size is the number of bytes in the message
232 (with 30 minutes the maximum time allowed).
233 The exit status of the process is consulted in determining the success
235 of the action. An exit status of zero means that the action succeeded.
236 Any other exit status (or abnormal termination) means that the action
237 failed.
238 In order to avoid any time limitations, you might implement a process
240 that began by fork()-ing. The parent would return the appropriate
241 value immediately, and the child could continue on, doing whatever it
242 wanted for as long as it wanted. This approach is somewhat risky if
243 the parent is going to return an exit status of zero. If the parent is
244 going to return a non-zero exit status, then this approach can lead to
245 quicker delivery into your maildrop.
246
249 /etc/nmh/mts.conf nmh mts configuration file
250 $HOME/.maildelivery The file controlling local delivery
251 /etc/nmh/maildelivery Rather than the standard file
252 /var/mail/$USER The default maildrop
253
256 rcvdist(1), rcvpack(1), rcvstore(1), rcvtty(1), mh-format(5)
257
260 `-noverbose'
261 `-nosuppressdup'
262 `-maildelivery' defaults to $HOME/.maildelivery
263 `-mailbox' deaults to /var/mail/$USER
264 `-file' defaults to stdin
265 `-user' defaults to the current user
266
269 None
270
273 Slocal was originally designed to be backward-compatible with the
274 maildelivery facility provided by MMDF-II. Thus, the “.maildelivery”
275 file syntax is somewhat limited. But slocal has been modified and
276 extended, so that is it no longer compatible with MMDF-II.
277 In addition to an exit status of zero, the MMDF values RP_MOK (32) and
279 RP_OK [22m(9) mean that the message has been fully delivered. Any other
280 non-zero exit status, including abnormal termination, is interpreted as
281 the MMDF value RP_MECH [22m(200), which means “use an alternate route”
282 (deliver the message to the maildrop).
283
286 Only two return codes are meaningful, others should be.
287 Slocal was originally designed to be backwards-compatible with the
289 maildelivery functionality provided by MMDF-II.
290MH.6.8 1 Jul 2003 SLOCAL(1)