FTP in gawk - awk

Hello,
I am building a suite of awk scripts to support a website CMS (content
management system) that I am building. I am trying to reduce the
dependency on lots of supplemental programs, so I am doing stuff in
gawk that is probably not best done in gawk ;-)

Below is an implementation of FTP in gawk (implementing just "put" not
"get" -- this script is meant to upload a bunch of rendered HTML,
images, etc to an FTP server running on a website). As I understand
BINMODE, it wasn't supposed to be used this way, but it works (although
in practice any file containing the string in RS (BinRS) can screw it
up). In particular, I am opening the "passive TCP" connection (which
must be open before a STOR) with:

printf("") |& dataport;

before going into BINMODE. This appears to NOT send anything but opens
the connection anyway. Is this reliable, or am I exploiting behavior
that may change in future releases of gawk?

I am abusing gawk and BINMODE in other scripts too, including a base64
decode, mime extractor, etc.

For those interested (or may find an awk based FTP script useful), here
it is (approx 100 lines) -- Warning, it has only been tested on a
couple of FTP servers...

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#!/usr/bin/gawk -f
#
# ftpput - put files via ftp
#
# Author: Todd Coram (todd at maplefish DOT com).
# Version: 0.9 1/9/2006
#
# A simple ftp file "put" transfer script. If a -d is supplied then try
and
# make the directories that are part of each file's filepath. 'rootdir'
is the remote
# FTP server directory to CWD to before starting the transfers.
#

BEGIN {
if (ARGC < 5) {
print "Usage: ftpput [-d] host user rootdir password file1 ..
fileN" \
>"/dev/stderr";
exit 1
}

# The record separator is set to a string that should
(statistically?)
# not occur even in binary data (ha!). We append a pid so that this
# app can transfer itself (makes the separator dynamic).
#
BinRS="yummydeadbeaf" PROCINFO["pid"];

Verbose=1;
RS = ORS = "\r\n";

mkdir = (optidx = (ARGV[1] == "-d") ? 2 : 1) - 1;
host = ARGV[optidx++]
user = ARGV[optidx++]
pass = ARGV[optidx++]
rootdir = ARGV[optidx++]

Ftphost = "/inet/tcp/0/" host "/21";
expect("", "220");
if (expect("USER " user, "331|230") ~ "^331") {
expect("PASS " pass, "230");
}
expect("TYPE I", "200");
expect("CWD " rootdir, "200|250");

for (; optidx < ARGC; optidx++) {
if (mkdir) mkdirhier(ARGV[optidx]);
pasv_send(ARGV[optidx]);
}

expect("QUIT", "221");
}

function mkdirhier(file, part,pidx,pcnt,dir) {
pcnt = split(file, part, "/")
for (pidx = 1; pidx < pcnt; pidx++) {
dir = (pidx == 1) ? part[pidx] : dir "/" part[pidx];
expect("MKD " dir, "250|257|521");
}
}

function pasv_send(file, ln,oldrs,oldbinmode,addr,port,dataport) {
ln = expect("PASV", "227");
if (!match(ln,
/([0-9]+),([0-9]+),([0-9]+),([0-9]+),([0-9]+),([0-9]+)/,aa)) {
print "Couldn't parse connection information from " ln
>"/dev/stderr";
exit 1;
}
addr = aa[1] "." aa[2] "." aa[3] "." aa[4];
port = (aa[5]*256)+aa[6];
dataport = "/inet/tcp/0/" addr "/" port;
printf("") |& dataport; # force connection open

expect("STOR " file, "150");
if (Verbose) printf(" * Sending %s to %s\n", file, dataport)
>"/dev/stderr";

oldrs = RS; RS = BinRS; ORS = "";
oldbinmode = BINMODE; BINMODE="rw";

while ((getline ln <file) > 0) {
print ln |& dataport; fflush(dataport);
}
close(dataport);
close(file);

RS = ORS = oldrs;
BINMODE = oldbinmode;

expect("","226");
}

function expect(query,code, line, a) {
if (query != "") {
print query |& Ftphost;
if (Verbose) printf("Sending: %s\n", query);
}
Ftphost |& getline line;
if (Verbose) printf(" Got: %s\n", line);
if (match(line,"^(" code ")",a)) {
return line;
}
printf("ERROR on (%s): Expected (%s). Got %s\n",
query, code, line) > "/dev/stderr";
exit 1;
}

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