BUFFCHAN(8) | InterNetNews Documentation | BUFFCHAN(8) |
buffchan - Buffered file-writing backend for INN
buffchan [-bru] [-c lines] [-C seconds] [-d directory] [-f num-fields] [-l lines] [-L seconds] [-m map] [-p pid-file] [-s format]
buffchan reads lines from standard input and copies the initial fields in each line to the files named by the remaining fields on the line. buffchan is intended to be called by innd as an exploder feed.
The 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 and do not contain any whitespace. The default number of initial fields is one.
For each line of input, buffchan writes the initial fields, separated by a space and followed by a newline, to each of the files named in the filename fields. The output files are kept open and are only flushed or closed based on the schedule given by the -c, -C, -l, and -L options.
As an exploder feed (see newsfeeds(5) for an explanation), buffchan interprets lines beginning with an exclamation point as commands. Besides "!begin" (which only marks the start of the feed), there are three supported commands:
Applications can tell that flush has completed by renaming the file before issuing the command. When the original file name has reappeared, the flush is complete. If fchmod(3) is available, buffchan also changes the file to read-only while it's actively writing to it and changes it back to read/write once it has been closed. It will change the mode back to read-only only if it reopens the same file.
When a "ctlinnd drop site" command is sent, innd will automatically forward the command to buffchan if the site is listed as a funnel feeding into the buffchan exploder. To drop all sites, use "ctlinnd send buffchan-site drop".
Once buffchan opens a file, it keeps it open (in the absence of a drop command). The input must therefore never specify more files than the maximum number of files a process may open.
In the map file, blank lines and lines starting with a number sign ("#") are ignored. All other lines should have two host names separated by a colon. The first field is the name that may appear in the input stream; the second field names the file to be used when the name in the first field appears. For example:
# This is a comment uunet:news.uu.net foo:foo.com munnari:munnari.oz.au
If buffchan is invoked with "-f 2" and given the following input:
news/software/b/132 <1643@munnari.oz.au> foo uunet news/software/b/133 <102060@litchi.foo.com> uunet munnari comp/sources/unix/2002 <999@news.foo.com> foo uunet munnari
Then the file foo will have these lines:
news/software/b/132 <1643@munnari.oz.au> comp/sources/unix/2002 <999@news.foo.com>
the file munnari will have these lines:
news/software/b/133 <102060@litchi.foo.com> comp/sources/unix/2002 <999@news.foo.com>
and the file uunet will have these lines:
news/software/b/132 <1643@munnari.oz.au> news/software/b/133 <102060@litchi.foo.com> comp/sources/unix/2002 <999@news.foo.com>
Written by Rich $alz <rsalz@uunet.uu.net> for InterNetNews. Converted to POD by Russ Allbery <eagle@eyrie.org>.
$Id: buffchan.pod 9767 2014-12-07 21:13:43Z iulius $
ctlinnd(8), filechan(8), inn.conf(5), innd(8), newsfeeds(5).
2015-09-12 | INN 2.6.3 |