Source Code 1992 March/Source_Code_CD-ROM_Walnut_Creek_March_1992.iso/usenet/compsrcs/misc/volume06/mverify

Internet Message Format | 1991-08-27 | 7.9 KB

From decwrl!ucbvax!agate!helios.ee.lbl.gov!ncis.llnl.gov!lll-winken!uunet!allbery Fri Mar 24 22:25:46 PST 1989
Article 831 of comp.sources.misc:
Path: decwrl!ucbvax!agate!helios.ee.lbl.gov!ncis.llnl.gov!lll-winken!uunet!allbery
From: [e-mail] (Brandon S. Allbery - comp.sources.misc)
Newsgroups: comp.sources.misc
Subject: v06i064: mverify - Mail alias/user verification
Message-ID: <[e-mail]>
Date: 21 Mar 89 01:37:06 GMT
Sender: [e-mail]
Reply-To: [e-mail] (Jeff Beadles)
Lines: 266
Approved: [e-mail] (Brandon S. Allbery - comp.sources.misc)

Posting-number: Volume 6, Issue 64
Submitted-by: [e-mail] (Jeff Beadles)
Archive-name: mverify

This program opens a connection to SMTP sendmail on a target host.  It then
attempts to verify that an alias/user exists in the eyes of the sendmail.

I use it to verify users on remote hosts without waiting for mail to bounce.

    -Jeff Beadles

--
Jeff Beadles
[e-mail]


#--------------------------------CUT HERE-------------------------------------
#! /bin/sh
#
# This is a shell archive.  Save this into a file, edit it
# and delete all lines above this comment.  Then give this
# file to sh by executing the command "sh file".  The files
# will be extracted into the current directory owned by
# you with default permissions.
#
# The files contained herein are:
#
# -rw-r--r--  1 jeff         1647 Mar  7 20:32 README
# -rw-r--r--  1 jeff         4049 Mar  6 10:47 mverify.c
#
echo 'x - README'
if test -f README; then echo 'shar: not overwriting README'; else
sed 's/^X//' << '________This_Is_The_END________' > README
X
XRequirements:    SMTP sendmail on the receiving (target) host, and an OS that
X        supports sockets.
X
XTo compile:    "make mverify"    (Yes that's right, there's no makefile.)
X       (or) cc -O -o mverify mverify.c
X
XTo execute:    "mverify user@host"
X
X---------------------------------------------------------------------------
Xmverify.c    Copyright 1989, Jeff Beadles [e-mail]
X
XPermission is granted to freely copy this program without charge.
XIf you distribute a binary to someone, you must also provide the source
Xupon request.
X
XThis started out as a little tool, and a learning experience for sockets &
Xthe like.  If you find it useful, then good for you.  If not, then read rm(1).
XWhat it does is fairly simple. It opens a connection to SMTP sendmail on a
Xtarget host.  It then attempts to verify that the user exists in the eyes
Xof the sendmail.  For example:  Let's say that I want to know who the
Xuser/alias 'postmaster@quark' expanded to.  Mverify would be invoked as:
X
X% mverify postmaster@quark
X
XJeff Beadles  jeff
X
XWith the /usr/lib/sendmail -bv command/option, it would only tell you that
Xthe mail was 'deliverable' if the target was on another host.
X
XMost all of the error messages should be self explainatory.
X
XAs long as the local host can find the target host DIRECTLY, it
Xshould work.  This program has no concept of mail domains.
XIf it is given a domain-style host, it truncates everything up to
Xincluding the first '.'  IE:  [e-mail] = jeff@quark
X
XIf you think of something useful to add, please send it to me, and
XI'll see about adding it.
X
XJeff Beadles
[e-mail]
X...!uunet!tektronix.TEK.COM!quark.WV!jeff
________This_Is_The_END________
if test `wc -l < README` -ne 43; then
    echo 'shar: README was damaged during transit (should have been 43 lines)'
fi
fi        ; : end of overwriting check
echo 'x - mverify.c'
if test -f mverify.c; then echo 'shar: not overwriting mverify.c'; else
sed 's/^X//' << '________This_Is_The_END________' > mverify.c
X/*
X * mverify.c    Copyright 1989, Jeff Beadles
X *                [e-mail]
X *
X *    Permission is granted to freely copy this program without charge.
X *    There are a couple of lines of autobounce.c by Pete Shipley
X *    [e-mail].
X *
X *    To compile, cc -o mverify mverify  : To use, mverify user@host
X *
X *    Note:  This program has no concept of mail domains.
X *    If it is given a domain-style host, it truncates everything up to
X *    including the '.'  IE:  [e-mail] = jeff@quark
X *
X *    This started out as a little tool.  If you find it useful, then
X *    good for you.  If not, then read rm(1).
X *
X *    If you think of something useful to add, please send it to me, and
X *    I'll see about adding it.
X *
X *    Jeff Beadles
X *    [e-mail]
X *
X */
X
X/* #define index strchr   /* */
X
X#include <sys/param.h>
X#include <sys/socket.h>
X#include <netdb.h>
X#include <netinet/in.h>
X#include <stdio.h>
X#include <strings.h>
X
Xmain(argc, argv)
Xint argc;
Xchar **argv;
X{
X    FILE    *fin;
X    FILE    *fout;
X    char    *retval,
X        *fgets(),
X        *index(),
X        buffer[2048],
X        targetuser[1024],
X        targethost[1024];
X
X    int    s;
X    struct    servent  *sp;
X    struct    hostent *hp, *gethostbyname();
X    struct    sockaddr_in server;
X
X    if ( argc != 2) {
X        (void)fprintf(stderr,"Usage: %s user@host\n",argv[0]);
X        exit(1);
X    }
X    strcpy(targetuser,argv[1]);
X    if( (retval=index(targetuser,'@')) == 0) {
X        (void)fprintf(stdout,"Usage: %s user@host\n",argv[0]);
X        exit(1);
X    }
X    *retval='\0';
X    retval++;
X    strcpy(targethost,retval);
X    if ( (retval=index(targethost,'.')) != 0) {
X           fprintf(stderr,"\nWarning: I do not know about mail domains.\n");
X           fprintf(stderr,"Converting %s to ",targethost);
X           *retval='\0';
X           fprintf(stderr,"%s\n\n",targethost);
X    }
X
X/*
X *    One socket please...
X */
X    if ( (s = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
X        perror("opening stream socket");
X        exit(1);
X    }
X/*
X *    Now get the information for the @host part of the address.
X */
X    server.sin_family = AF_INET;
X    if ( (hp = gethostbyname(targethost)) == 0) {
X        (void) fprintf(stderr, "%s: unknown host\n", targethost);
X        exit(2);
X    }
X
X
X/*
X *    Now get the smtp port using tcp.
X */
X    bcopy(hp->h_addr, (char *)&server.sin_addr, hp->h_length);
X    sp = getservbyname("smtp", "tcp");
X    server.sin_port = sp->s_port;
X    if(server.sin_port == htons(0)) {
X        (void)fprintf(stderr,"Unknown service: smtp/tcp\n");
X        exit(1);
X    }
X
X/*
X *    Connecting to the socket might make things go a little easier...  :-)
X */
X    if (connect(s, (struct sockaddr *)&server, sizeof(server)) < 0) {
X        perror("connecting stream socket");
X        exit(1);
X    }
X
X/*
X *    Change the to streams 'cause I like'em better.
X */
X    fout = fdopen(s,"w");
X    fin  = fdopen(s,"r");
X
X/*
X *    Wait for the smtp mailer to answer.  It will greet us with:
X * 220 quark.WV.TEK.COM Sendmail 5.17/6.24 ready at Thu, 2 Mar 89 23:52:29 PST
X */
X    while( (retval=fgets(buffer,sizeof(buffer) - 1,fin)) != NULL) {
X        if ( !strncmp(buffer,"220 ",4))
X            break;
X    }
X
X/*
X *    Now that we have the mailers attention, tell it to 'verify' the user.
X */
X    fprintf(fout,"\nVRFY %s\n",targetuser);
X    fflush(fout);
X
X/*
X *    Now just go into a loop reading responces from the mailer.
X */
X    while( (retval=fgets(buffer,sizeof(buffer) -1,fin)) != NULL) {
X/*
X *    Zap ^M < > from the lines.
X */
X        if ( (retval=index(buffer,'\r')) != 0)
X            *retval='\0';
X        if ( (retval=index(buffer,'<')) != 0)
X            *retval=' ';
X        if ( (retval=index(buffer,'>')) != 0)
X            *retval=' ';
X/*
X *    250 = valid data follows.  If true, then this is a valid line.
X *    The +4 skips the '250-'
X */
X        if ( !strncmp(buffer,"250",3)) {
X            puts( buffer + 4);
X        }
X/*
X *     550 is 'Command unrecognized.  Tell the user and exit.
X *    The +4 skips the '550-'
X */
X        if ( !strncmp(buffer,"550",3)) {
X            puts( buffer + 4);
X            break;
X        }
X/*
X * If "250 " then this was the last line of data.
X * (Note the space.  a '-' means that there's still more to come.)
X */
X        if ( !strncmp(buffer,"250 ", 4))
X            break;
X    }
X/*
X *    Close the SMTP connection.
X */
X    fputs("\n\nQUIT\n", fout);
X    fflush(fout);
X    fclose(fout);
X    fclose(fin);
X/*
X *    And leave this nice program.
X */
X    exit(0);
X}
X
________This_Is_The_END________
if test `wc -l < mverify.c` -ne 176; then
    echo 'shar: mverify.c was damaged during transit (should have been 176 lines)'
fi
fi        ; : end of overwriting check
exit 0