1BUFFCHAN(8) InterNetNews Documentation BUFFCHAN(8)
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6 buffchan - Buffered file-writing backend for INN
7
9 buffchan [-bru] [-c lines] [-C seconds] [-d directory] [-f num-fields]
10 [-l lines] [-L seconds] [-m map] [-p pid-file] [-s format]
11
13 buffchan reads lines from standard input and copies the initial fields
14 in each line to the files named by the remaining fields on the line.
15 buffchan is intended to be called by innd as an exploder feed.
16 The input is interpreted as a sequence of lines. Each line contains a
18 fixed number of initial fields, followed by a variable number of
19 filename fields. All fields in a line are separated by whitespace and
20 do not contain any whitespace. The default number of initial fields is
21 one.
22 For each line of input, buffchan writes the initial fields, separated
24 by a space and followed by a newline, to each of the files named in the
25 filename fields. The output files are kept open and are only flushed
26 or closed based on the schedule given by the -c, -C, -l, and -L
27 options.
28 As an exploder feed (see newsfeeds(5) for an explanation), buffchan
30 interprets lines beginning with an exclamation point as commands.
31 Besides "!begin" (which only marks the start of the feed), there are
32 three supported commands:
33 !flush [site]
35 The flush command closes and reopens all open files. An optional
36 site can be specified, in which case buffchan flushes only that
37 file. This command is analogous to the "ctlinnd flush" command.
38 This command can be sent via innd using "ctlinnd send buffchan-site
39 'flush site'".
40 Applications can tell that flush has completed by renaming the file
42 before issuing the command. When the original file name has
43 reappeared, the flush is complete. If fchmod(3) is available,
44 buffchan also changes the file to read-only while it's actively
45 writing to it and changes it back to read/write once it has been
46 closed. It will change the mode back to read-only only if it
47 reopens the same file.
48 !drop [site]
50 The drop command is similar to the flush command, except that no
51 files are reopened. If given an argument, only the specified site
52 is dropped; otherwise, all sites are dropped. (Note that a site
53 will be restarted if the input stream mentions the site again.)
54 When a "ctlinnd drop site" command is sent, innd will automatically
56 forward the command to buffchan if the site is listed as a funnel
57 feeding into the buffchan exploder. To drop all sites, use
58 "ctlinnd send buffchan-site drop".
59 !readmap
61 The map file specified with the -m option, if given, will be
62 reloaded.
63 Once buffchan opens a file, it keeps it open (in the absence of a drop
65 command). The input must therefore never specify more files than the
66 maximum number of files a process may open.
67
69 -b Force the output to be buffered. (This is generally the default,
70 but it may depend on the operating system.) If -b is given, a
71 buffer size of BUFSIZ (a constant of the system standard I/O
72 library) is used.
73 -c lines
75 If the -c flag is given, buffchan will close and reopen a file
76 after every lines lines are written to the file.
77 -C seconds
79 If the -C flag is given, buffchan will close and reopen a file if
80 it has been open for more than seconds seconds.
81 -d directory
83 This flag may be used to specify a directory the program should
84 change to before starting. If this flag is used, the default for
85 the -s flag (see below) is changed to be a simple %s (in other
86 words, output files are considered to be relative to directory).
87 -f num-fields
89 By default, each line is expected to contain one fixed field
90 followed by some number of filename fields. If this flag is given,
91 num-fields will be used as the number of initial fixed fields.
92 -l lines
94 If the -l flag is given, buffchan will flush the output after every
95 lines lines are written to a file.
96 -L seconds
98 If the -L flag is given, buffchan will flush each output file every
99 seconds seconds.
100 -m map
102 Map files translate the names in the filename fields on each line
103 into filenames that should be used instead. It's used primarily
104 when short names are used in newsfeeds, but the output files should
105 use the full domain names of remote peers.
106 In the map file, blank lines and lines starting with a number sign
108 ("#") are ignored. All other lines should have two host names
109 separated by a colon. The first field is the name that may appear
110 in the input stream; the second field names the file to be used
111 when the name in the first field appears. For example:
112 # This is a comment
114 uunet:news.uu.net
115 foo:foo.com
116 munnari:munnari.oz.au
117 -p pid-file
119 If the -p option is given, buffchan will write a line containing
120 its process ID (in text) to the specified file when it starts.
121 -r By default, buffchan sends its error messages to pathlog/errlog.
123 To suppress this redirection and send error messages to standard
124 error, use the -r flag.
125 -s The -s flag may be used to specify a format that maps a filename
127 from the filename fields at the end of each line to an actual
128 filename. This is a sprintf(3) format string that should contain a
129 single instance of %s, which will be replaced with the value of the
130 filename field (possibly after mapping with the map file from -m).
131 The default value is pathoutgoing/%s.
132 -u If the -u flag is used, the output will be unbuffered.
134
136 If buffchan is invoked with "-f 2" and given the following input:
137 news/software/b/132 <1643@munnari.oz.au> foo uunet
139 news/software/b/133 <102060@litchi.foo.com> uunet munnari
140 comp/sources/unix/2002 <999@news.foo.com> foo uunet munnari
141 Then the file foo will have these lines:
143 news/software/b/132 <1643@munnari.oz.au>
145 comp/sources/unix/2002 <999@news.foo.com>
146 the file munnari will have these lines:
148 news/software/b/133 <102060@litchi.foo.com>
150 comp/sources/unix/2002 <999@news.foo.com>
151 and the file uunet will have these lines:
153 news/software/b/132 <1643@munnari.oz.au>
155 news/software/b/133 <102060@litchi.foo.com>
156 comp/sources/unix/2002 <999@news.foo.com>
157
159 Written by Rich $alz <rsalz@uunet.uu.net> for InterNetNews. Converted
160 to POD by Russ Allbery <eagle@eyrie.org>.
161 $Id: buffchan.pod 9767 2014-12-07 21:13:43Z iulius $
163
165 ctlinnd(8), filechan(8), inn.conf(5), innd(8), newsfeeds(5).
166INN 2.6.4 2015-09-12 BUFFCHAN(8)