diff options
Diffstat (limited to '')
| -rw-r--r-- | upstream/opensuse-tumbleweed/man5/mmdf_mutt.5 | 164 |
1 files changed, 164 insertions, 0 deletions
diff --git a/upstream/opensuse-tumbleweed/man5/mmdf_mutt.5 b/upstream/opensuse-tumbleweed/man5/mmdf_mutt.5 new file mode 100644 index 00000000..e14d72b5 --- /dev/null +++ b/upstream/opensuse-tumbleweed/man5/mmdf_mutt.5 @@ -0,0 +1,164 @@ +.\" Project : tin +.\" Module : mmdf.5 +.\" Author : U. Janssen +.\" Created : 2002-02-18 +.\" Updated : +.\" Notes : needs a lot of work +.\" +.TH mmdf 5 "February 18th, 2002" "Unix" "User Manuals" +.\" +.SH NAME +MMDF \- Multi\-channel Memorandum Distribution Facility mailbox format +.\" +.SH DESCRIPTION +This document describes the +.B MMDF +mailbox format used by some MTAs and MUAs (i.e. +.BR scomail (1)) +to store mail messages locally. +.PP +An +.B MMDF +mailbox is a text file containing an arbitrary number of e-mail messages. +Each message consists of a postmark, followed by an e-mail message formatted +according to \fBRFC822\fP / \fBRFC2822\fP, followed by a postmark. The file +format is line-oriented. Lines are separated by line feed characters (ASCII +10). A postmark line consists of the four characters "^A^A^A^A" (Control-A; +ASCII 1). +.TP +Example of a \fBMMDF\fP mailbox holding two mails: +.RS +.nf +.sp +^A^A^A^A +.br +From: example@example.com +.br +To: example@example.org +.br +Subject: test +.br +.sp +.br +>From what I learned about the MMDF-format: +.br +.br +^A^A^A^A +.br +^A^A^A^A +.br +From: example@example.com +.br +To: example@example.org +.br +Subject: test 2 +.br +.sp +.br +bar +.br +^A^A^A^A +.fi +.RE +.PP +In contrast to most other single file mailbox formats like +MBOXO and MBOXRD (see +.BR mbox (5)) +there is no need to quote/dequote "From "\-lines in +.B MMDF +mailboxes as such lines have no special meaning in this format. +.PP +If the modification-time (usually determined via +.BR stat (2)) +of a nonempty mailbox file is greater than the access-time +the file has new mail. Many MUAs place a Status: header in +each message to indicate which messages have already been +read. +.\" +.SH LOCKING +Since +.B MMDF +files are frequently accessed by multiple programs in parallel, +.B MMDF +files should generally not be accessed without locking. +.PP +Three different locking mechanisms (and combinations thereof) are in +general use: +.IP "\(bu" +.BR fcntl (2) +locking is mostly used on recent, POSIX-compliant systems. Use of +this locking method is, in particular, advisable if +.B MMDF +files are accessed through the Network File System (NFS), since it +seems the only way to reliably invalidate NFS clients' caches. +.IP "\(bu" +.BR flock (2) +locking is mostly used on BSD-based systems. +.IP "\(bu" +Dotlocking is used on all kinds of systems. In order to lock an +.B MMDF +file named \fIfolder\fR, an application first creates a temporary file +with a unique name in the directory in which the +\fIfolder\fR resides. The application then tries to use the +.BR link (2) +system call to create a hard link named \fIfolder.lock\fR +to the temporary file. The success of the +.BR link (2) +system call should be additionally verified using +.BR stat (2) +calls. If the link has succeeded, the mail folder is considered +dotlocked. The temporary file can then safely be unlinked. +.IP "" +In order to release the lock, an application just unlinks the +\fIfolder.lock\fR file. +.PP +If multiple methods are combined, implementors should make sure to +use the non-blocking variants of the +.BR fcntl (2) +and +.BR flock (2) +system calls in order to avoid deadlocks. +.PP +If multiple methods are combined, an +.B MMDF +file must not be considered to have been successfully locked before +all individual locks were obtained. When one of the individual +locking methods fails, an application should release all locks it +acquired successfully, and restart the entire locking procedure from +the beginning, after a suitable delay. +.PP +The locking mechanism used on a particular system is a matter of +local policy, and should be consistently used by all applications +installed on the system which access +.B MMDF +files. Failure to do so may result in loss of e-mail data, and in +corrupted +.B MMDF +files. +.\" +.\" .SH FILES +.\" /usr/spool/mmdf/lock/home +.\" $HOME/Mail/ +.\" +.\" .SH SECURITY +.\" +.SH "CONFORMING TO" +.B MMDF +is not part of any currently supported standard. +.\" +.SH HISTORY +.B MMDF +was developed at the University of Delaware by Dave Crocker. +.\" +.SH "SEE ALSO" +.BR scomail (1), +.BR fcntl (2), +.BR flock (2), +.BR link (2), +.BR stat (2), +.BR mbox (5), +.BR RFC822 , +.BR RFC2822 + +.SH AUTHOR +Urs Janssen <urs@tin.org> |