buffchan - buffered file-writing backend for InterNetNews

buffchan [ -b ] [ -c lines ] [ -C seconds ] [ -d directory ] [ -f num_fields ] [ -m map ] [ -p pidfile ] [ -l lines ] [ -L seconds ] [ -r ] [ -s filename_format ] [ -u ]

Buffchan reads lines from standard input and copies certain fields in each line into files named by other fields within the line. Buffchan is intended to be called by innd(8) as an exploder feed.

-b

Once buffchan opens a file it keeps it open. The input must therefore never specify more files than the number of available descriptors can keep open. If the ``-b'' flag is used, the program will allocate a buffer and attach it to the file using setbuf(3).

-c lines

If the ``-c'' flag is used, buffchan will close, and re-open, a file after every lines lines are written to a file.

-C seconds

Similarly, the ``-C'' flag may be used to specify that all files should be closed and re-opened every seconds seconds.

-d directory

The ``-d'' flag may be used to specify a directory the program should change to before starting. If this flag is used, then the default for the ``-s'' flag is changed to be a simple ``%s''.

-f num_fields

Buffchan input is interpreted as a sequence of lines. Each line contains a fixed number of initial fields, followed by a variable number of filename fields. All fields in a line are separated by whitespace. The default number of initial fields is one; the ``-f'' flag may be used to specify a different number of fields.

-m map

Map files specify short names as aliases for domain names; see filechan(8) for details and an example.

-p pidfile

If the ``-p'' flag is used, the program will write a line containing its process ID (in text) to the specified file.

-l lines

If the ``-l'' flag is used, buffchan will call fflush(3) after every lines lines are written to a file.

-L seconds

If the ``-L'' flag is used, all files will be flushed every n seconds.

-r

By default, the program sends its error messages to <pathlog in inn.conf>/errlog. To suppress this redirection and send error messages to standard error, use the ``-r'' flag.

-s filename_format

After the initial fields, each remaining field names a file to write. The ``-s'' flag may be used to specify a format string that maps the field to a file name. This is a sprintf(3) format string which should have a single ``%s'' parameter which will be given the contents of a non-initial field. The default value is <pathoutgoing in inn.conf>/%s. See the description of this flag in filechan(8).

-u

If the ``-u'' flag is used, the program will request unbuffered output.

Buffchan can be invoked as an exploder feed (see newsfeeds(5)). As such, if a line starts with an exclamation point it will be treated as a command. There are three commands, described below:

flush

The ``flush'' command closes and re-opens all open files; ``flush xxx'' which flushes only the specified site. These are analogous to the ctlinnd(8) ``flush'' command, and can be achieved by doing a ``send "flush xxx"'' command. Applications can tell that the ``flush'' has completed by renaming the file before issuing the command; buffchan has completed the command when the original filename re-appears. If <$ac_cv_func_fchmod in config.cache> is ``yes'', then buffchan also changes the access permissions of the file from read-only for everyone to read-write for owner and group as it flushes or closes each output file. It will change the modes back to read-only if it re-opens the same file.

drop

The ``drop'' command is similar to the ``flush'' command except that no files are re-opened. If given an argument, then the specified site is dropped, otherwise all sites are dropped. (Note that the site will be restarted if the input stream mentions the site.) When a ctlinnd ``drop site'' command is sent, innd will automatically forward the command to buffchan for sites listed as funnels feeding into this exploder. To drop all sites, use the ctlinnd ``send buffchan-site drop'' command.

readmap

The map file (specified with the ``-m'' flag) is reloaded.

Written by Rich $alz <rsalz@uunet.uu.net> for InterNetNews.

ctlinnd(8), filechan(8), inn.conf(5), innd(8), newsfeeds(5).