gawk smtp

[codemut]

Here's a quiz...

How to use smtp with gawk. What works on the bash command line is not working in an awk script. Consider the following code:

BEGIN {
RS = ORS = "\r\n"
to = "name@server.com"
from = "name2@server.com"
text = "testing1...testing2...testing3..."
subject = "testing 1...2...3"
smtp = "mail.server.com"
connection = "/inet/tcp/0/"smtp"/25"

print "HELO "smtp |& connection; connection |& getline
print "MAIL FROM:<"from">" |& connection; connection |& getline
print "RCPT TO:<"to">" |& connection; connection |& getline
print "DATA" |& connection; connection |& getline
print "Subject: "subject"\n"text |& connection; connection |& getline
print "." |& smtp; connection |& getline
print "QUIT" |& connection; connection |& getline
close(connection);
}

The fix might be to correct the read of server messages after each print with the two-way pipe ability of |&

 

[Annihilannic]

As far as I can tell (and I haven't used it much), |& is for communicating with a co-process. In your example connection is not a process (or command), but just the file itself.

I think the solution is simpler than what you're trying to do, i.e.:

   print "HELO "smtp > connection
   getline smtpoutput < connection
   print smtpoutput

Annihilannic.

 

[feherke]

Hi

In your example connection is not a process (or command), but just the file itself.

Nope. It is a socket. For example this will get the Tek-Tips main page :

[red]BEGIN[/red] [teal]{[/teal]
  host[teal]=[/teal][green][i]"tek-tips.com"[/i][/green]
  c[teal]=[/teal][green][i]"/inet/tcp/0/"[/i][/green] host [green][i]"/80"[/i][/green]
  [COLOR=chocolate]print[/color] [green][i]"GET / HTTP/1.0[/i][/green][lime][i]\n[/i][/lime][green][i]Host: "[/i][/green] host [green][i]"[/i][/green][lime][i]\n[/i][/lime][green][i]"[/i][/green] [teal]|&[/teal] c
  [b]while[/b] [teal]([/teal]c [teal]|&[/teal] [COLOR=chocolate]getline[/color] str[teal])[/teal] [COLOR=chocolate]print[/color] [COLOR=chocolate]gensub[/color][teal](/<[^<>]+>/,[/teal][green][i]""[/i][/green][teal],[/teal][green][i]"g"[/i][/green][teal],[/teal]str[teal])[/teal]
[teal]}[/teal]

zedlan, I would not suppose that all SMTP servers will send exactly one line of response after each received line. So I would enclose those [tt]connection |& getline[/tt] commands in [tt]while[/tt] loops to ensure they can be executed zero or more times if needed.

Feherke.

http://rootshell.be/~feherke/

 

[Annihilannic]

Yep, I realise it is a socket... but "everything in Unix is a file" as the saying goes, so what I was saying was that it behaves the same way as a file, not the same way as a process.

Annihilannic.

 

[feherke]

Hi

Well, my example certainly works with co-process piping ( [tt]|&[/tt] ) and certainly not works with redirecting ( [tt]<[/tt] [tt]>[/tt] ). So I would say, socket communications are like inter-process communications, at least in [tt]gawk[/tt]. And zedlan's original code seems to be correct, just naive because assumes fixed amount of response.

Feherke.

http://rootshell.be/~feherke/

 

[codemut]

A print statement was added to view server info. The "print "HELO ..." statement yields the server's 1st msg: "220 mail.server.com ESMTP" ... then the script hangs w/out any further output (even with the above code suggestions).

Maybe fflush() or close() is in order... but how to do w/out disconnecting? Maybe a "wait" command like w/ bash?

By the way, a typo was fixed -- line 15 should have read: "print "." |& connection ...".

With http there are no such difficulties. For smtp, server interaction seems a puzzle.

 

[Annihilannic]

I sit corrected... however still confused because the gawk man page clearly says that "c" should be a command rather than a file/pipe/socket:

command |& getline [var]
Run command as a co-process piping the output
either into $0 or var, as above. Co-processes
are a gawk extension.

It would make more sense to me if "c" was defined to be something like "cat <> /inet/tcp/0/" host "/80", for example.

Anyway... if zedlan were to use a while loop as you suggested, wouldn't it just wait indefinitely until the connection is closed? I don't think getline will return false just because there is no further input available right now.

zedlan, I just ran your original code on a HP-UX 11.11 system with sendmail 8.9.3 and it worked perfectly, mail received. What OS and MTA are trying with?


Annihilannic.

 

[feherke]

Hi

Anyway... if zedlan were to use a while loop as you suggested, wouldn't it just wait indefinitely until the connection is closed?

Is your turn to be right. Indeed, that will not work. Sorry, it seemed that I did it like that some years ago.


Feherke.

http://rootshell.be/~feherke/

 

[codemut]

Annihilannic,

The systems are freeBSD w/sendmail and openSuse w/postfix.

However, given the new service of connection = "/inet/tcp/0/"smtp"/25", is the local mta relevant?

A successful local test makes it all the more puzzling since the same parameters work via command line/telnet to the remote host. There are no clues in the mail logs.

 

[Annihilannic]

Err, yeah, sorry, forgot I changed it to "localhost" for my own test.

Annihilannic.