Fossil

  socketErrMsg = vmprintf(zFormat, ap);
  va_end(ap);
}

/*
** Return the current socket error message
*/
char *socket_errmsg(void){
  char *zResult = socketErrMsg;
  socketErrMsg = 0;
  return zResult;
}

/*
** Call this routine once before any other use of the socket interface.
** This routine does initial configuration of the socket module.
*/
void socket_global_init(void){

  }
  for(i=2; i<g.argc; i++){
    char *z = smtp_mx_host(g.argv[i]);
    fossil_print("%s: %s\n", g.argv[i], z);
    fossil_free(z);
  }
}

#if INTERFACE
/*
** Information about a single SMTP connection.
*/
struct SmtpSession {
  const char *zFrom;        /* Domain from which we are sending */
  const char *zDest;        /* Domain that will receive the email */
  char *zHostname;          /* Hostname of SMTP server for zDest */
  u32 smtpFlags;            /* Flags changing the operation */
  FILE *logFile;            /* Write session transcript to this log file */
  Blob *pTranscript;        /* Record session transcript here */
  const char *zLabel;       /* Either "CS" or "SC" */
  char *zErr;               /* Error message */
};

/* Allowed values for SmtpSession.smtpFlags */
#define SMTP_TRACE_STDOUT   0x00001     /* Debugging info to console */
#define SMTP_TRACE_FILE     0x00002     /* Debugging info to logFile */
#define SMTP_TRACE_BLOB     0x00004     /* Record transcript */

#endif

/*
** Shutdown an SmtpSession
*/
void smtp_session_free(SmtpSession *pSession){
  socket_close();
  fossil_free(pSession->zHostname);
  fossil_free(pSession->zErr);
  fossil_free(pSession);
}

/*
** Allocate a new SmtpSession object.
**
** Both zFrom and zDest must be specified for a client side SMTP connection.
** For a server-side, specify only zFrom.
*/
SmtpSession *smtp_session_new(
  const char *zFrom,    /* Domain name of our end. */
  const char *zDest,    /* Domain of the other end. */
  u32 smtpFlags,        /* Flags */
  ...                   /* Arguments depending on the flags */
){
  SmtpSession *p;
  va_list ap;
  UrlData url;

  p = fossil_malloc( sizeof(*p) );
  memset(p, 0, sizeof(*p));
  p->zFrom = zFrom;
  p->zDest = zDest;
  p->zLabel = zDest==0 ? "CS" : "SC";
  p->smtpFlags = smtpFlags;
  va_start(ap, smtpFlags);
  if( smtpFlags & SMTP_TRACE_FILE ){
    p->logFile = va_arg(ap, FILE*);
  }else if( smtpFlags & SMTP_TRACE_BLOB ){
    p->pTranscript = va_arg(ap, Blob*);
  }
  va_end(ap);
  p->zHostname = smtp_mx_host(zDest);
  if( p->zHostname==0 ){
    p->zErr = mprintf("cannot locate SMTP server for \"%s\"", zDest);
    return p;
  }
  memset(&url, 0, sizeof(url));
  url.name = p->zHostname;
  url.port = 25;
  socket_global_init();
  if( socket_open(&url) ){
    p->zErr = socket_errmsg();
    socket_close();
  }
  return p;
}

/*
** Send a single line of output the SMTP client to the server.
*/
static void smtp_send_line(SmtpSession *p, const char *zFormat, ...){
  Blob b = empty_blob;
  va_list ap;
  char *z;
  int n;
  va_start(ap, zFormat);
  blob_vappendf(&b, zFormat, ap);
  va_end(ap);
  z = blob_buffer(&b);
  n = blob_size(&b);
  assert( n>=2 );
  assert( z[n-1]=='\n' );
  assert( z[n-2]=='\r' );
  if( p->smtpFlags & SMTP_TRACE_STDOUT ){
    fossil_print("%c: %.*s\n", p->zLabel[1], n-2, z);
  }
  if( p->smtpFlags & SMTP_TRACE_FILE ){
    fprintf(p->logFile, "%c: %.*s\n", p->zLabel[1], n-2, z);
  }
  if( p->smtpFlags & SMTP_TRACE_BLOB ){
    blob_appendf(p->pTranscript, "%c: %.*s\n", p->zLabel[1], n-2, z);
  }
  socket_send(0, z, n);
  blob_zero(&b);
}

/*
** Read a line of input received from the SMTP server.  Append
** the received line onto the end of the blob.
*/
static void smtp_recv_line(SmtpSession *p, Blob *in){
  int n = blob_size(in);
  int iStart = n;
  char *z;
  do{
    size_t got;
    blob_resize(in, n+1000);
    z = blob_buffer(in);
    got = socket_receive(0, z+n, 1000);
    in->nUsed += got;
    n += got;
  }while( n<1 || z[n-1]!='\n' );
  z = blob_buffer(in) + iStart;
  n = blob_size(in) - iStart - 1;
  if( n && z[n-1]=='\r' ) n--;
  if( p->smtpFlags & SMTP_TRACE_STDOUT ){
    fossil_print("%c: %.*s\n", p->zLabel[0], n, z);
  }
  if( p->smtpFlags & SMTP_TRACE_FILE ){
    fprintf(p->logFile, "%c: %.*s\n", p->zLabel[0], n, z);
  }
  if( p->smtpFlags & SMTP_TRACE_BLOB ){
    blob_appendf(p->pTranscript, "%c: %.*s\n", p->zLabel[0], n-2, z);
  }
}

/*
** Capture a single-line server reply.
*/
static void smtp_get_reply_from_server(
  SmtpSession *p,   /* The SMTP connection */
  Blob *in,         /* Buffer used to hold the reply */
  int *piCode,      /* The return code */
  int *pbMore,      /* True if the reply is not complete */
  char **pzArg      /* Argument */
){
  blob_truncate(in, 0);
  smtp_recv_line(p, in);
  *piCode = atoi(blob_str(in));
  *pbMore = blob_size(in)>=4 && blob_str(in)[3]=='-';
  *pzArg = blob_size(in)>=4 ? blob_str(in)+4 : "";
}

/*
** Have the client send a QUIT message.
*/
int smtp_client_quit(SmtpSession *p){
  Blob in = BLOB_INITIALIZER;
  int iCode = 0;
  int bMore = 0;
  char *zArg = 0;
  smtp_send_line(p, "QUIT\r\n");
  do{
    smtp_get_reply_from_server(p, &in, &iCode, &bMore, &zArg);
  }while( bMore );
  socket_close();
  return 0;
}

/*
** Begin a client SMTP session.  Wait for the initial 220 then send
** the EHLO and wait for a 250.
**
** Return 0 on success and non-zero for a failure.
*/
int smtp_client_startup(SmtpSession *p){
  Blob in = BLOB_INITIALIZER;
  int iCode = 0;
  int bMore = 0;
  char *zArg = 0;
  do{
    smtp_get_reply_from_server(p, &in, &iCode, &bMore, &zArg);
  }while( bMore );
  if( iCode!=220 ){
    smtp_client_quit(p);
    return 1;
  }
  smtp_send_line(p, "EHLO %s\r\n", p->zFrom);
  do{
    smtp_get_reply_from_server(p, &in, &iCode, &bMore, &zArg);
  }while( bMore );
  if( iCode!=250 ){
    smtp_client_quit(p);
    return 1;
  }
  return 0;
}

/*
** COMMAND: test-smtp-probe
**
** Usage: %fossil test-smtp-probe DOMAIN ME
**
** Interact with the SMTP server for DOMAIN by setting up a connection
** and then immediately shutting it back down.  Log all interaction
** on the console.  Use ME as the domain name of the sender.
*/
void test_smtp_probe(void){
  char *zHost;
  SmtpSession *p;
  int rc;
  if( g.argc!=4 ) usage("DOMAIN ME");
  zHost = smtp_mx_host(g.argv[2]);
  if( zHost==0 ){
    fossil_fatal("cannot resolve the MX for \"%s\"", g.argv[2]);
  }
  fossil_print("Contacting host \"%s\"\n", zHost);
  p = smtp_session_new(g.argv[3], zHost, SMTP_TRACE_STDOUT);
  rc = smtp_client_startup(p);
  if( !rc ) smtp_client_quit(p);
  smtp_session_free(p);
}