pop3.c

#endif

/* For USER responses */
static CURLcode pop3_state_user_resp(struct connectdata *conn, int pop3code,
                                     pop3state instate)
{
  CURLcode result = CURLE_OK;
  struct SessionHandle *data = conn->data;

  (void)instate; /* no use for this yet */

  if(pop3code != '+') {
    failf(data, "Access denied. %c", pop3code);
    result = CURLE_LOGIN_DENIED;
  }
  else
    /* Send the PASS command */
    result = Curl_pp_sendf(&conn->proto.pop3c.pp, "PASS %s",
                           conn->passwd ? conn->passwd : "");
  if(!result)
    state(conn, POP3_PASS);

  return result;
}

/* For PASS responses */
static CURLcode pop3_state_pass_resp(struct connectdata *conn, int pop3code,
                                     pop3state instate)
{
  CURLcode result = CURLE_OK;
  struct SessionHandle *data = conn->data;

  (void)instate; /* no use for this yet */

  if(pop3code != '+') {
    failf(data, "Access denied. %c", pop3code);
    result = CURLE_LOGIN_DENIED;
  }
  else
    /* End of connect phase */
    state(conn, POP3_STOP);

  return result;
}

/* Start the DO phase for the command */
static CURLcode pop3_command(struct connectdata *conn)
{
  CURLcode result = CURLE_OK;
  struct SessionHandle *data = conn->data;
  struct POP3 *pop3 = data->state.proto.pop3;
  const char *command = NULL;

  /* Calculate the default command */
  if(pop3->id[0] == '\0' || conn->data->set.ftp_list_only) {
    command = "LIST";

    if(pop3->id[0] != '\0')
      /* Message specific LIST so skip the BODY transfer */
      pop3->transfer = FTPTRANSFER_INFO;
  }
  else
    command = "RETR";

  /* Send the command */
  if(pop3->id[0] != '\0')
    result = Curl_pp_sendf(&conn->proto.pop3c.pp, "%s %s",
                           (pop3->custom && pop3->custom[0] != '\0' ?
                            pop3->custom : command), pop3->id);
  else
    result = Curl_pp_sendf(&conn->proto.pop3c.pp,
                           (pop3->custom && pop3->custom[0] != '\0' ?
                            pop3->custom : command));

  if(!result)
    state(conn, POP3_COMMAND);

  return result;
}

/* For command responses */
static CURLcode pop3_state_command_resp(struct connectdata *conn,
                                        int pop3code,
                                        pop3state instate)
{
  CURLcode result = CURLE_OK;
  struct SessionHandle *data = conn->data;
  struct POP3 *pop3 = data->state.proto.pop3;
  struct pop3_conn *pop3c = &conn->proto.pop3c;
  struct pingpong *pp = &pop3c->pp;

  (void)instate; /* no use for this yet */

  if(pop3code != '+') {
    state(conn, POP3_STOP);
    return CURLE_RECV_ERROR;
  }

  /* This 'OK' line ends with a CR LF pair which is the two first bytes of the
     EOB string so count this is two matching bytes. This is necessary to make
     the code detect the EOB if the only data than comes now is %2e CR LF like
     when there is no body to return. */
  pop3c->eob = 2;

  /* But since this initial CR LF pair is not part of the actual body, we set
     the strip counter here so that these bytes won't be delivered. */
  pop3c->strip = 2;

  if(pop3->transfer == FTPTRANSFER_BODY) {
    /* POP3 download */
    Curl_setup_transfer(conn, FIRSTSOCKET, -1, FALSE, NULL, -1, NULL);

    if(pp->cache) {
      /* The header "cache" contains a bunch of data that is actually body
         content so send it as such. Note that there may even be additional
         "headers" after the body */

      if(!data->set.opt_no_body) {
        result = Curl_pop3_write(conn, pp->cache, pp->cache_size);
        if(result)
          return result;
      }

      /* Free the cache */
      Curl_safefree(pp->cache);

      /* Reset the cache size */
      pp->cache_size = 0;
    }
  }

  /* End of DO phase */
  state(conn, POP3_STOP);

  return result;
}

static CURLcode pop3_statemach_act(struct connectdata *conn)
{
  CURLcode result = CURLE_OK;
  curl_socket_t sock = conn->sock[FIRSTSOCKET];
  int pop3code;
  struct pop3_conn *pop3c = &conn->proto.pop3c;
  struct pingpong *pp = &pop3c->pp;
  size_t nread = 0;

  /* Busy upgrading the connection; right now all I/O is SSL/TLS, not POP3 */
  if(pop3c->state == POP3_UPGRADETLS)
    return pop3_state_upgrade_tls(conn);

  /* Flush any data that needs to be sent */
  if(pp->sendleft)
    return Curl_pp_flushsend(pp);

  /* Read the response from the server */
  result = Curl_pp_readresp(sock, pp, &pop3code, &nread);
  if(result)
    return result;

  if(pop3code) {
    /* We have now received a full POP3 server response */
    switch(pop3c->state) {
    case POP3_SERVERGREET:
      result = pop3_state_servergreet_resp(conn, pop3code, pop3c->state);
      break;

    case POP3_CAPA:
      result = pop3_state_capa_resp(conn, pop3code, pop3c->state);
      break;

    case POP3_STARTTLS:
      result = pop3_state_starttls_resp(conn, pop3code, pop3c->state);
      break;

    case POP3_AUTH_PLAIN:
      result = pop3_state_auth_plain_resp(conn, pop3code, pop3c->state);
      break;

    case POP3_AUTH_LOGIN:
      result = pop3_state_auth_login_resp(conn, pop3code, pop3c->state);
      break;

    case POP3_AUTH_LOGIN_PASSWD:
      result = pop3_state_auth_login_password_resp(conn, pop3code,
                                                   pop3c->state);
      break;

#ifndef CURL_DISABLE_CRYPTO_AUTH
    case POP3_AUTH_CRAMMD5:
      result = pop3_state_auth_cram_resp(conn, pop3code, pop3c->state);
      break;

    case POP3_AUTH_DIGESTMD5:
      result = pop3_state_auth_digest_resp(conn, pop3code, pop3c->state);
      break;

    case POP3_AUTH_DIGESTMD5_RESP:
      result = pop3_state_auth_digest_resp_resp(conn, pop3code, pop3c->state);
      break;
#endif

#ifdef USE_NTLM
    case POP3_AUTH_NTLM:
      result = pop3_state_auth_ntlm_resp(conn, pop3code, pop3c->state);
      break;

    case POP3_AUTH_NTLM_TYPE2MSG:
      result = pop3_state_auth_ntlm_type2msg_resp(conn, pop3code,
                                                  pop3c->state);
      break;
#endif

    case POP3_AUTH_FINAL:
      result = pop3_state_auth_final_resp(conn, pop3code, pop3c->state);
      break;

#ifndef CURL_DISABLE_CRYPTO_AUTH
    case POP3_APOP:
      result = pop3_state_apop_resp(conn, pop3code, pop3c->state);
      break;
#endif

    case POP3_USER:
      result = pop3_state_user_resp(conn, pop3code, pop3c->state);
      break;

    case POP3_PASS:
      result = pop3_state_pass_resp(conn, pop3code, pop3c->state);
      break;

    case POP3_COMMAND:
      result = pop3_state_command_resp(conn, pop3code, pop3c->state);
      break;

    case POP3_QUIT:
      /* fallthrough, just stop! */
    default:
      /* internal error */
      state(conn, POP3_STOP);
      break;
    }
  }

  return result;
}

/* Called repeatedly until done from multi.c */
static CURLcode pop3_multi_statemach(struct connectdata *conn, bool *done)
{
  CURLcode result = CURLE_OK;
  struct pop3_conn *pop3c = &conn->proto.pop3c;

  if((conn->handler->flags & PROTOPT_SSL) && !pop3c->ssldone)
    result = Curl_ssl_connect_nonblocking(conn, FIRSTSOCKET, &pop3c->ssldone);
  else
    result = Curl_pp_statemach(&pop3c->pp, FALSE);

  *done = (pop3c->state == POP3_STOP) ? TRUE : FALSE;

  return result;
}

static CURLcode pop3_block_statemach(struct connectdata *conn)
{
  CURLcode result = CURLE_OK;
  struct pop3_conn *pop3c = &conn->proto.pop3c;

  while(pop3c->state != POP3_STOP && !result)
    result = Curl_pp_statemach(&pop3c->pp, TRUE);

  return result;
}

/* Allocate and initialize the POP3 struct for the current SessionHandle if
   required */
static CURLcode pop3_init(struct connectdata *conn)
{
  CURLcode result = CURLE_OK;
  struct SessionHandle *data = conn->data;
  struct POP3 *pop3 = data->state.proto.pop3;

  if(!pop3) {
    pop3 = data->state.proto.pop3 = calloc(sizeof(struct POP3), 1);
    if(!pop3)
      result = CURLE_OUT_OF_MEMORY;
  }

  return result;
}

/* For the POP3 "protocol connect" and "doing" phases only */
static int pop3_getsock(struct connectdata *conn, curl_socket_t *socks,
                        int numsocks)
{
  return Curl_pp_getsock(&conn->proto.pop3c.pp, socks, numsocks);
}

/***********************************************************************
 *
 * pop3_connect()
 *
 * This function should do everything that is to be considered a part of the
 * connection phase.
 *
 * The variable 'done' points to will be TRUE if the protocol-layer connect
 * phase is done when this function returns, or FALSE is not. When called as
 * a part of the easy interface, it will always be TRUE.
 */
static CURLcode pop3_connect(struct connectdata *conn, bool *done)
{
  CURLcode result = CURLE_OK;
  struct pop3_conn *pop3c = &conn->proto.pop3c;
  struct pingpong *pp = &pop3c->pp;

  *done = FALSE; /* default to not done yet */

  /* If there already is a protocol-specific struct allocated for this
     sessionhandle, deal with it */
  Curl_reset_reqproto(conn);

  /* Initialise the POP3 layer */
  result = pop3_init(conn);
  if(result)
    return result;

  /* We always support persistent connections in POP3 */
  conn->bits.close = FALSE;

  /* Set the default response time-out */
  pp->response_time = RESP_TIMEOUT;
  pp->statemach_act = pop3_statemach_act;
  pp->endofresp = pop3_endofresp;
  pp->conn = conn;

  /* Initialise the pingpong layer */
  Curl_pp_init(pp);

  /* Start off waiting for the server greeting response */
  state(conn, POP3_SERVERGREET);

  result = pop3_multi_statemach(conn, done);

  return result;
}

/***********************************************************************
 *
 * pop3_done()
 *
 * The DONE function. This does what needs to be done after a single DO has
 * performed.
 *
 * Input argument is already checked for validity.
 */
static CURLcode pop3_done(struct connectdata *conn, CURLcode status,
                          bool premature)
{
  CURLcode result = CURLE_OK;
  struct SessionHandle *data = conn->data;
  struct POP3 *pop3 = data->state.proto.pop3;

  (void)premature;

  if(!pop3)
    /* When the easy handle is removed from the multi interface while libcurl
       is still trying to resolve the host name, the POP3 struct is not yet
       initialized. However, the removal action calls Curl_done() which in
       turn calls this function, so we simply return success. */
    return CURLE_OK;

  if(status) {
    conn->bits.close = TRUE; /* marked for closure */
    result = status;         /* use the already set error code */
  }

  /* Cleanup our per-request based variables */
  Curl_safefree(pop3->id);
  Curl_safefree(pop3->custom);

  /* Clear the transfer mode for the next request */
  pop3->transfer = FTPTRANSFER_BODY;

  return result;
}

/***********************************************************************
 *
 * pop3_perform()
 *
 * This is the actual DO function for POP3. Get a message/listing according to
 * the options previously setup.
 */
static CURLcode pop3_perform(struct connectdata *conn, bool *connected,
                             bool *dophase_done)
{
  /* This is POP3 and no proxy */
  CURLcode result = CURLE_OK;

  DEBUGF(infof(conn->data, "DO phase starts\n"));

  if(conn->data->set.opt_no_body) {
    /* Requested no body means no transfer */
    struct POP3 *pop3 = conn->data->state.proto.pop3;
    pop3->transfer = FTPTRANSFER_INFO;
  }

  *dophase_done = FALSE; /* not done yet */

  /* Start the first command in the DO phase */
  result = pop3_command(conn);
  if(result)
    return result;

  /* Run the state-machine */
  result = pop3_multi_statemach(conn, dophase_done);

  *connected = conn->bits.tcpconnect[FIRSTSOCKET];

  if(*dophase_done)
    DEBUGF(infof(conn->data, "DO phase is complete\n"));

  return result;
}

/***********************************************************************
 *
 * pop3_do()
 *
 * This function is registered as 'curl_do' function. It decodes the path
 * parts etc as a wrapper to the actual DO function (pop3_perform).
 *
 * The input argument is already checked for validity.
 */
static CURLcode pop3_do(struct connectdata *conn, bool *done)
{
  CURLcode result = CURLE_OK;

  *done = FALSE; /* default to false */

  /* Since connections can be re-used between SessionHandles, there might be a
     connection already existing but on a fresh SessionHandle struct. As such
     we make sure we have a good POP3 struct to play with. For new connections
     the POP3 struct is allocated and setup in the pop3_connect() function. */
  Curl_reset_reqproto(conn);
  result = pop3_init(conn);
  if(result)
    return result;

  /* Parse the URL path */
  result = pop3_parse_url_path(conn);
  if(result)
    return result;

  /* Parse the custom request */
  result = pop3_parse_custom_request(conn);
  if(result)
    return result;

  result = pop3_regular_transfer(conn, done);

  return result;
}

/***********************************************************************
 *
 * pop3_quit()
 *
 * Performs the quit action prior to sclose() be called.
 */
static CURLcode pop3_quit(struct connectdata *conn)
{
  CURLcode result = CURLE_OK;

  /* Send the QUIT command */
  result = Curl_pp_sendf(&conn->proto.pop3c.pp, "QUIT");

  if(!result)
    state(conn, POP3_QUIT);

  return result;
}

/***********************************************************************
 *
 * pop3_disconnect()
 *
 * Disconnect from an POP3 server. Cleanup protocol-specific per-connection
 * resources. BLOCKING.
 */
static CURLcode pop3_disconnect(struct connectdata *conn,
                                bool dead_connection)
{
  struct pop3_conn *pop3c = &conn->proto.pop3c;

  /* We cannot send quit unconditionally. If this connection is stale or
     bad in any way, sending quit and waiting around here will make the
     disconnect wait in vain and cause more problems than we need to. */

  /* The POP3 session may or may not have been allocated/setup at this
     point! */
  if(!dead_connection && pop3c->pp.conn)
    if(!pop3_quit(conn))
      (void)pop3_block_statemach(conn); /* ignore errors on QUIT */

  /* Disconnect from the server */
  Curl_pp_disconnect(&pop3c->pp);

  /* Cleanup the SASL module */
  Curl_sasl_cleanup(conn, pop3c->authused);

  /* Cleanup our connection based variables */
  Curl_safefree(pop3c->apoptimestamp);

  return CURLE_OK;
}

/***********************************************************************
 *
 * pop3_parse_url_path()
 *
 * Parse the URL path into separate path components.
 */
static CURLcode pop3_parse_url_path(struct connectdata *conn)
{
  /* The POP3 struct is already initialised in pop3_connect() */
  struct SessionHandle *data = conn->data;
  struct POP3 *pop3 = data->state.proto.pop3;
  const char *path = data->state.path;

  /* URL decode the path for the message ID */
  return Curl_urldecode(data, path, 0, &pop3->id, NULL, TRUE);
}

static CURLcode pop3_parse_custom_request(struct connectdata *conn)
{
  CURLcode result = CURLE_OK;
  struct SessionHandle *data = conn->data;
  struct POP3 *pop3 = data->state.proto.pop3;
  const char *custom = data->set.str[STRING_CUSTOMREQUEST];

  /* URL decode the custom request */
  if(custom)
    result = Curl_urldecode(data, custom, 0, &pop3->custom, NULL, TRUE);

  return result;
}

/* Call this when the DO phase has completed */
static CURLcode pop3_dophase_done(struct connectdata *conn, bool connected)
{
  struct POP3 *pop3 = conn->data->state.proto.pop3;

  (void)connected;

  if(pop3->transfer != FTPTRANSFER_BODY)
    /* no data to transfer */
    Curl_setup_transfer(conn, -1, -1, FALSE, NULL, -1, NULL);

  return CURLE_OK;
}

/* Called from multi.c while DOing */
static CURLcode pop3_doing(struct connectdata *conn, bool *dophase_done)
{
  CURLcode result = pop3_multi_statemach(conn, dophase_done);

  if(result)
    DEBUGF(infof(conn->data, "DO phase failed\n"));
  else if(*dophase_done) {
    result = pop3_dophase_done(conn, FALSE /* not connected */);

    DEBUGF(infof(conn->data, "DO phase is complete\n"));
  }

  return result;
}

/***********************************************************************
 *
 * pop3_regular_transfer()
 *
 * The input argument is already checked for validity.
 *
 * Performs all commands done before a regular transfer between a local and a
 * remote host.
 */
static CURLcode pop3_regular_transfer(struct connectdata *conn,
                                      bool *dophase_done)
{
  CURLcode result = CURLE_OK;
  bool connected = FALSE;
  struct SessionHandle *data = conn->data;

  /* Make sure size is unknown at this point */
  data->req.size = -1;

  /* Set the progress data */
  Curl_pgrsSetUploadCounter(data, 0);
  Curl_pgrsSetDownloadCounter(data, 0);
  Curl_pgrsSetUploadSize(data, 0);
  Curl_pgrsSetDownloadSize(data, 0);

  /* Carry out the perform */
  result = pop3_perform(conn, &connected, dophase_done);

  /* Perform post DO phase operations if necessary */
  if(!result && *dophase_done)
    result = pop3_dophase_done(conn, connected);

  return result;
}

static CURLcode pop3_setup_connection(struct connectdata *conn)
{
  struct SessionHandle *data = conn->data;

  if(conn->bits.httpproxy && !data->set.tunnel_thru_httpproxy) {
    /* Unless we have asked to tunnel POP3 operations through the proxy, we
       switch and use HTTP operations only */
#ifndef CURL_DISABLE_HTTP
    if(conn->handler == &Curl_handler_pop3)
      conn->handler = &Curl_handler_pop3_proxy;
    else {
#ifdef USE_SSL
      conn->handler = &Curl_handler_pop3s_proxy;
#else
      failf(data, "POP3S not supported!");
      return CURLE_UNSUPPORTED_PROTOCOL;
#endif
    }

    /* We explicitly mark this connection as persistent here as we're doing
       POP3 over HTTP and thus we accidentally avoid setting this value
       otherwise */
    conn->bits.close = FALSE;
#else
    failf(data, "POP3 over http proxy requires HTTP support built-in!");
    return CURLE_UNSUPPORTED_PROTOCOL;
#endif
  }

  data->state.path++;   /* don't include the initial slash */

  return CURLE_OK;
}

/* This function scans the body after the end-of-body and writes everything
   until the end is found */
CURLcode Curl_pop3_write(struct connectdata *conn, char *str, size_t nread)
{
  /* This code could be made into a special function in the handler struct */
  CURLcode result = CURLE_OK;
  struct SessionHandle *data = conn->data;
  struct SingleRequest *k = &data->req;

  struct pop3_conn *pop3c = &conn->proto.pop3c;
  bool strip_dot = FALSE;
  size_t last = 0;
  size_t i;

  /* Search through the buffer looking for the end-of-body marker which is
     5 bytes (0d 0a 2e 0d 0a). Note that a line starting with a dot matches
     the eob so the server will have prefixed it with an extra dot which we
     need to strip out. Additionally the marker could of course be spread out
     over 5 different data chunks. */
  for(i = 0; i < nread; i++) {
    size_t prev = pop3c->eob;

    switch(str[i]) {
    case 0x0d:
      if(pop3c->eob == 0) {
        pop3c->eob++;

        if(i) {
          /* Write out the body part that didn't match */
          result = Curl_client_write(conn, CLIENTWRITE_BODY, &str[last],
                                     i - last);

          if(result)
            return result;

          last = i;
        }
      }
      else if(pop3c->eob == 3)
        pop3c->eob++;
      else
        /* If the character match wasn't at position 0 or 3 then restart the
           pattern matching */
        pop3c->eob = 1;
      break;

    case 0x0a:
      if(pop3c->eob == 1 || pop3c->eob == 4)
        pop3c->eob++;
      else
        /* If the character match wasn't at position 1 or 4 then start the
           search again */
        pop3c->eob = 0;
      break;

    case 0x2e:
      if(pop3c->eob == 2)
        pop3c->eob++;
      else if(pop3c->eob == 3) {
        /* We have an extra dot after the CRLF which we need to strip off */
        strip_dot = TRUE;
        pop3c->eob = 0;
      }
      else
        /* If the character match wasn't at position 2 then start the search
           again */
        pop3c->eob = 0;
      break;

    default:
      pop3c->eob = 0;
      break;
    }

    /* Did we have a partial match which has subsequently failed? */
    if(prev && prev >= pop3c->eob) {
      /* Strip can only be non-zero for the very first mismatch after CRLF
         and then both prev and strip are equal and nothing will be output
         below */
      while(prev && pop3c->strip) {
        prev--;
        pop3c->strip--;
      }

      if(prev) {
        /* If the partial match was the CRLF and dot then only write the CRLF
           as the server would have inserted the dot */
        result = Curl_client_write(conn, CLIENTWRITE_BODY, (char*)POP3_EOB,
                                   strip_dot ? prev - 1 : prev);

        if(result)
          return result;

        last = i;
        strip_dot = FALSE;
      }
    }
  }

  if(pop3c->eob == POP3_EOB_LEN) {
    /* We have a full match so the transfer is done, however we must transfer
    the CRLF at the start of the EOB as this is considered to be part of the
    message as per RFC-1939, sect. 3 */
    result = Curl_client_write(conn, CLIENTWRITE_BODY, (char *)POP3_EOB, 2);

    k->keepon &= ~KEEP_RECV;
    pop3c->eob = 0;

    return result;
  }

  if(pop3c->eob)
    /* While EOB is matching nothing should be output */
    return CURLE_OK;

  if(nread - last) {
    result = Curl_client_write(conn, CLIENTWRITE_BODY, &str[last],
                               nread - last);
  }

  return result;
}

#endif /* CURL_DISABLE_POP3 */