+#ifdef SUPPORT_TLS
+/*****************************************************
+* Proxy TLS connection for another transport process *
+******************************************************/
+/*
+Close the unused end of the pipe, fork once more, then use the given buffer
+as a staging area, and select on both the given fd and the TLS'd client-fd for
+data to read (per the coding in ip_recv() and fd_ready() this is legitimate).
+Do blocking full-size writes, and reads under a timeout. Once both input
+channels are closed, exit the process.
+
+Arguments:
+ buf space to use for buffering
+ bufsiz size of buffer
+ pfd pipe filedescriptor array; [0] is comms to proxied process
+ timeout per-read timeout, seconds
+*/
+
+void
+smtp_proxy_tls(uschar * buf, size_t bsize, int * pfd, int timeout)
+{
+fd_set rfds, efds;
+int max_fd = MAX(pfd[0], tls_out.active) + 1;
+int rc, i, fd_bits, nbytes;
+
+close(pfd[1]);
+if ((rc = fork()))
+ {
+ DEBUG(D_transport) debug_printf("proxy-proc final-pid %d\n", rc);
+ _exit(rc < 0 ? EXIT_FAILURE : EXIT_SUCCESS);
+ }
+
+if (running_in_test_harness) millisleep(100); /* let parent debug out */
+set_process_info("proxying TLS connection for continued transport");
+FD_ZERO(&rfds);
+FD_SET(tls_out.active, &rfds);
+FD_SET(pfd[0], &rfds);
+
+for (fd_bits = 3; fd_bits; )
+ {
+ time_t time_left = timeout;
+ time_t time_start = time(NULL);
+
+ /* wait for data */
+ efds = rfds;
+ do
+ {
+ struct timeval tv = { time_left, 0 };
+
+ rc = select(max_fd,
+ (SELECT_ARG2_TYPE *)&rfds, NULL, (SELECT_ARG2_TYPE *)&efds, &tv);
+
+ if (rc < 0 && errno == EINTR)
+ if ((time_left -= time(NULL) - time_start) > 0) continue;
+
+ if (rc <= 0)
+ {
+ DEBUG(D_transport) if (rc == 0) debug_printf("%s: timed out\n", __FUNCTION__);
+ goto done;
+ }
+
+ if (FD_ISSET(tls_out.active, &efds) || FD_ISSET(pfd[0], &efds))
+ {
+ DEBUG(D_transport) debug_printf("select: exceptional cond on %s fd\n",
+ FD_ISSET(pfd[0], &efds) ? "proxy" : "tls");
+ goto done;
+ }
+ }
+ while (rc < 0 || !(FD_ISSET(tls_out.active, &rfds) || FD_ISSET(pfd[0], &rfds)));
+
+ /* handle inbound data */
+ if (FD_ISSET(tls_out.active, &rfds))
+ if ((rc = tls_read(FALSE, buf, bsize)) <= 0)
+ {
+ fd_bits &= ~1;
+ FD_CLR(tls_out.active, &rfds);
+ shutdown(pfd[0], SHUT_WR);
+ timeout = 5;
+ }
+ else
+ {
+ for (nbytes = 0; rc - nbytes > 0; nbytes += i)
+ if ((i = write(pfd[0], buf + nbytes, rc - nbytes)) < 0) goto done;
+ }
+ else if (fd_bits & 1)
+ FD_SET(tls_out.active, &rfds);
+
+ /* handle outbound data */
+ if (FD_ISSET(pfd[0], &rfds))
+ if ((rc = read(pfd[0], buf, bsize)) <= 0)
+ {
+ fd_bits = 0;
+ tls_close(FALSE, TRUE);
+ }
+ else
+ {
+ for (nbytes = 0; rc - nbytes > 0; nbytes += i)
+ if ((i = tls_write(FALSE, buf + nbytes, rc - nbytes, FALSE)) < 0)
+ goto done;
+ }
+ else if (fd_bits & 2)
+ FD_SET(pfd[0], &rfds);
+ }
+
+done:
+ if (running_in_test_harness) millisleep(100); /* let logging complete */
+ exim_exit(0, US"TLS proxy");
+}
+#endif
+
+