Date: Sun, 13 Sep 1998 09:51:13 -0500 (CDT) From: Conrad Sabatier <conrads@neosoft.com> To: freebsd-stable@FreeBSD.ORG Subject: Awk problem (bug?) Message-ID: <XFMail.980913095113.conrads@neosoft.com>
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If this would be better posted to another list, please let me know, and I'll
remail it.
Background:
FreeBSD 2.2.7-STABLE, cvsup/make world/kernel build done on Aug 28, 1998.
I recently decided to try writing an external filtering program for "suck".
Here's the mechanism as described in the suck man page:
1. suck will write a 8 byte long string, which rep-
resents the length of the header record on stdin of
the external program. Then length is in ascii, is
left-aligned, and ends in a newline (example: "1234
\n").
2. suck will then write the header on stdin of the
external program.
3. suck will wait for a 2 character response code
on stdout. This response code is either "0\n" or
"1\n" (NOT BINARY ZERO OR ONE, ASCII ZERO OR ONE).
If the return code is zero, suck will download the
article, if it is one, suck won't.
4. When there are no more articles, the length
written down (for step 1) will be zero (again in
ascii "0 \n"). Suck will then wait for the
external program to exit before continuing on. The
external program can do any clean up it needs, then
exit. Note: suck will not continue processing
until the external program exits.
Unfortunately, my awk script would not communicate properly with suck using the
standard /usr/bin/awk. For some reason, the result string my script was
writing to stdout was not being read by suck, and both the script and suck
would simply hang in a piperd state.
So, I installed kawk from the ports collection, and it worked!
Here's the script. So far, it just checks the Newsgroups: header against the
active file and rejects the article if any group is not found:
#!/usr/local/bin/kawk -f
BEGIN {
active = "/usr/local/news/lib/active"
logfile = "/usr/local/news/suck.kill.log"
stdin = "/dev/stdin"
stdout = "/dev/stdout"
}
# size of header?
/^[0-9]+ *$/ \
{
FS = " "
if ($1 == "0")
{
print "===== NO MORE ARTICLES =====" >> logfile
exit
}
headsize = int($1)
size = 0
next
}
# All other header lines
{
print $0 >> logfile
FS = " "
size += (length + 1)
if ($1 == "Newsgroups:")
{
NGS = $2
FS = ","
n = split ($2, group)
FS = " "
act_groups = 0
for (i = 1; i <= n; i++)
{
while (getline <active)
{
if ($1 == group[i])
{
act_groups++
break
}
}
close (active)
if (act_groups < i)
{
break
}
}
}
if (size >= headsize)
{
if (act_groups < n)
{
print "===== ARTICLE REJECTED =====" >> logfile
print "1" >stdout
}
else
{
print "===== ARTICLE ACCEPTED =====" >> logfile
print "0" >stdout
}
next
}
}
----------------------------------
E-Mail: Conrad Sabatier <conrads@neosoft.com>
Date: 13-Sep-98
Time: 09:38:11
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