Add -J and -j to the TLS tools to check for peer close_notify.

 Also, and more importantly, significantly rewrite stls_run()
for better full-duplex support. This implementation isn't fully
tested yet.

Signed-off-by: Laurent Bercot <ska@appnovation.com>

22 files changed, 261 insertions, 214 deletions

diff --git a/doc/s6-tlsc-io.html b/doc/s6-tlsc-io.html
index f4a81a2..17a4e26 100644
--- a/doc/s6-tlsc-io.html
+++ b/doc/s6-tlsc-io.html
@@ -38,7 +38,7 @@ the options given when configuring s6-networking.
 <h2> Interface </h2>
 
 <pre>
-     s6-tlsc-io [ -S | -s ] [ -Y | -y ] [ -v <em>verbosity</em> ] [ -K kimeout ] [ -k <em>servername</em> ] [ -d <em>notif</em> ] [ -- ] <em>fdr</em> <em>fdw</em>
+     s6-tlsc-io [ -S | -s ] [ -J | -j ] [ -Y | -y ] [ -v <em>verbosity</em> ] [ -K kimeout ] [ -k <em>servername</em> ] [ -d <em>notif</em> ] [ -- ] <em>fdr</em> <em>fdw</em>
 </pre>
 
 <ul>
@@ -190,6 +190,10 @@ no effect. </li>
 and break the connection when receiving a local EOF. </li>
  <li> <tt>-s</tt>&nbsp;: transmit EOF by half-closing the TCP
 connection without using <tt>close_notify</tt>. This is the default. </li>
+ <li> <tt>-J</tt>&nbsp;: treat EOF from the peer without a prior close_notify
+as an error: print a fatal error message and exit 98. </li>
+ <li> <tt>-j</tt>&nbsp;: treat EOF from the peer without a prior close_notify
+as a normal exit condition. This is the default. </li>
  <li> <tt>-Y</tt>&nbsp;: Do not send a client certificate. This is the default. </li>
  <li> <tt>-y</tt>&nbsp;: Send a client certificate. </li>
  <li> <tt>-k&nbsp;<em>servername</em></tt>&nbsp;: use Server Name
diff --git a/doc/s6-tlsc.html b/doc/s6-tlsc.html
index 1d11c5b..aff6828 100644
--- a/doc/s6-tlsc.html
+++ b/doc/s6-tlsc.html
@@ -29,7 +29,7 @@ TLS/SSL.
 <h2> Interface </h2>
 
 <pre>
-     s6-tlsc [ -S | -s ] [ -Y | -y ] [ -Z | -z ] [ -v <em>verbosity</em> ] [ -K kimeout ] [ -k <em>servername</em> ] [ -6 <em>rfd</em> ] [ -7 <em>wfd</em> ] [ -- ] <em>prog...</em>
+     s6-tlsc [ -S | -s ] [ -J | -j ] [ -Y | -y ] [ -Z | -z ] [ -v <em>verbosity</em> ] [ -K kimeout ] [ -k <em>servername</em> ] [ -6 <em>rfd</em> ] [ -7 <em>wfd</em> ] [ -- ] <em>prog...</em>
 </pre>
 
 <ul>
@@ -126,6 +126,9 @@ before execing <em>prog...</em>. This is the default. </li>
 and break the connection when <em>prog</em> sends EOF. </li>
  <li> <tt>-s</tt>&nbsp;: transmit EOF by half-closing the TCP
 connection without using <tt>close_notify</tt>. This is the default. </li>
+ <li> <tt>-J</tt>&nbsp;: make <a href="s6-tlsc-io.html">s6-tlsc-io</a>
+exit with a nonzero code if the peer sends EOF without a close_notify first </li>
+ <li> <tt>-j</tt>&nbsp;: treat EOF from the peer as a normal exit condition </li>
  <li> <tt>-Y</tt>&nbsp;: Do not send a client certificate. This is the default. </li>
  <li> <tt>-y</tt>&nbsp;: Send a client certificate. </li>
  <li> <tt>-k&nbsp;<em>servername</em></tt>&nbsp;: use Server Name
diff --git a/doc/s6-tlsclient.html b/doc/s6-tlsclient.html
index 287c02c..09276d4 100644
--- a/doc/s6-tlsclient.html
+++ b/doc/s6-tlsclient.html
@@ -144,6 +144,7 @@ generally work: the defaults are sensible.
  <li> <tt>-Z</tt>, <tt>-z</tt>&nbsp;: keep or remove the <a href="s6-tlsc-io.html">s6-tlsc-io</a>-specific
 variables from the application's environment </li>
  <li> <tt>-S</tt>, <tt>-s</tt>&nbsp;: use close_notify or EOF to signal the end of a TLS connection </li>
+ <li> <tt>-J</tt>, <tt>-j</tt>&nbsp;: exit nonzero with an error message when the peer fails to close_notify, or ignore it </li>
  <li> <tt>-Y</tt>, <tt>-y</tt>&nbsp;: don't send, or send, a client certificate </li>
  <li> <tt>-k <em>servername</em></tt>&nbsp;: use SNI and provide a server name </li>
  <li> <tt>-K <em>kimeout</em></tt>&nbsp;: set a timeout for the TLS handshake </li>
diff --git a/doc/s6-tlsd-io.html b/doc/s6-tlsd-io.html
index 0f3b922..55e293f 100644
--- a/doc/s6-tlsd-io.html
+++ b/doc/s6-tlsd-io.html
@@ -38,7 +38,7 @@ the options given when configuring s6-networking.
 <h2> Interface </h2>
 
 <pre>
-     s6-tlsd-io [ -S | -s ] [ -Y | -y ] [ -v <em>verbosity</em> ] [ -K <em>kimeout</em> ] [ -k <em>snilevel</em> ] [ -d <em>notif</em> ] [ -- ] <em>fdr</em> <em>fdw</em>
+     s6-tlsd-io [ -S | -s ] [ -J | -j ] [ -Y | -y ] [ -v <em>verbosity</em> ] [ -K <em>kimeout</em> ] [ -k <em>snilevel</em> ] [ -d <em>notif</em> ] [ -- ] <em>fdr</em> <em>fdw</em>
 </pre>
 
 <ul>
@@ -210,6 +210,10 @@ no effect. </li>
 and break the connection when receiving a local EOF. </li>
  <li> <tt>-s</tt>&nbsp;: transmit EOF by half-closing the TCP
 connection without using <tt>close_notify</tt>. This is the default. </li>
+ <li> <tt>-J</tt>&nbsp;: treat EOF from the peer without a prior close_notify
+as an error: print a fatal error message and exit 98. </li>
+ <li> <tt>-j</tt>&nbsp;: treat EOF from the peer without a prior close_notify
+as a normal exit condition. This is the default. </li>
  <li> <tt>-Y</tt>&nbsp;: Request a client certificate.
 The certificate is optional: if the client gives none, the connection
 proceeds. </li>
diff --git a/doc/s6-tlsd.html b/doc/s6-tlsd.html
index 883777b..73a9f9b 100644
--- a/doc/s6-tlsd.html
+++ b/doc/s6-tlsd.html
@@ -38,7 +38,7 @@ the options given when configuring <tt>s6-networking</tt>.
 <h2> Interface </h2>
 
 <pre>
-     s6-tlsd [ -S | -s ] [ -Y | -y ] [ -Z | -z ] [ -v <em>verbosity</em> ] [ -K <em>kimeout</em> ] [ -k <em>snilevel</em> ] [ -- ] <em>prog...</em>
+     s6-tlsd [ -S | -s ] [ -J | -j ] [ -Y | -y ] [ -Z | -z ] [ -v <em>verbosity</em> ] [ -K <em>kimeout</em> ] [ -k <em>snilevel</em> ] [ -- ] <em>prog...</em>
 </pre>
 
 <ul>
@@ -139,6 +139,9 @@ before execing <em>prog...</em>. This is the default. </li>
 and break the connection when <em>prog</em> sends EOF. </li>
  <li> <tt>-s</tt>&nbsp;: transmit EOF by half-closing the TCP
 connection without using <tt>close_notify</tt>. This is the default. </li>
+ <li> <tt>-J</tt>&nbsp;: make <a href="s6-tlsd-io.html">s6-tlsd-io</a>
+exit with a nonzero code if the peer sends EOF without a close_notify first </li>
+ <li> <tt>-j</tt>&nbsp;: treat EOF from the peer as a normal exit condition </li>
  <li> <tt>-Y</tt>&nbsp;: Request an optional client certificate. </li>
  <li> <tt>-y</tt>&nbsp;: Request a mandatory client certificate.
 The default, with neither the <tt>-Y</tt> nor the <tt>-y</tt> option,
diff --git a/doc/s6-tlsserver.html b/doc/s6-tlsserver.html
index d1ca3e2..8713235 100644
--- a/doc/s6-tlsserver.html
+++ b/doc/s6-tlsserver.html
@@ -177,6 +177,7 @@ certificates, you probably still want TCP access rules.
  <li> <tt>-Z</tt>, <tt>-z</tt>&nbsp;: keep or remove the <a href="s6-tlsd-io.html">s6-tlsd-io</a>-specific
 variables from the application's environment </li>
  <li> <tt>-S</tt>, <tt>-s</tt>&nbsp;: use close_notify or EOF to signal the end of a TLS connection </li>
+ <li> <tt>-J</tt>, <tt>-j</tt>&nbsp;: exit nonzero with an error message when the peer fails to close_notify, or ignore it </li>
  <li> <tt>-Y</tt>, <tt>-y</tt>&nbsp;: request an optional or a mandatory client certificate </li>
  <li> <tt>-K <em>kimeout</em></tt>&nbsp;: set a timeout for the TLS handshake </li>
  <li> <tt>-k <em>snilevel</em></tt>&nbsp;: support SNI-based certificate chains </li>
diff --git a/doc/s6-ucspitlsc.html b/doc/s6-ucspitlsc.html
index e096e24..52af6db 100644
--- a/doc/s6-ucspitlsc.html
+++ b/doc/s6-ucspitlsc.html
@@ -36,7 +36,7 @@ TLS stack in the client itself.
 <h2> Interface </h2>
 
 <pre>
-     s6-ucspitlsc [ -S | -s ] [ -Y | -y ] [ -Z | -z ] [ -v <em>verbosity</em> ] [ -K kimeout ] [ -k <em>servername</em> ] [ -6 <em>rfd</em> ] [ -7 <em>wfd</em> ] [ -- ] <em>prog...</em>
+     s6-ucspitlsc [ -S | -s ] [ -J | -j ] [ -Y | -y ] [ -Z | -z ] [ -v <em>verbosity</em> ] [ -K kimeout ] [ -k <em>servername</em> ] [ -6 <em>rfd</em> ] [ -7 <em>wfd</em> ] [ -- ] <em>prog...</em>
 </pre>
 
 <ul>
@@ -142,6 +142,9 @@ before execing <em>prog...</em>. This is the default. </li>
 and break the connection when <em>prog</em> sends EOF. </li>
  <li> <tt>-s</tt>&nbsp;: transmit EOF by half-closing the TCP
 connection without using <tt>close_notify</tt>. This is the default. </li>
+ <li> <tt>-J</tt>&nbsp;: make <a href="s6-tlsc-io.html">s6-tlsc-io</a>
+exit with a nonzero code if the peer sends EOF without a close_notify first </li>
+ <li> <tt>-j</tt>&nbsp;: treat EOF from the peer as a normal exit condition </li>
  <li> <tt>-Y</tt>&nbsp;: Do not send a client certificate. This is the default. </li>
  <li> <tt>-y</tt>&nbsp;: Send a client certificate. </li>
  <li> <tt>-k&nbsp;<em>servername</em></tt>&nbsp;: use Server Name
diff --git a/doc/s6-ucspitlsd.html b/doc/s6-ucspitlsd.html
index 8488942..314cc39 100644
--- a/doc/s6-ucspitlsd.html
+++ b/doc/s6-ucspitlsd.html
@@ -36,7 +36,7 @@ TLS stack in the server itself.
 <h2> Interface </h2>
 
 <pre>
-     s6-ucspitlsd [ -S | -s ] [ -Y | -y ] [ -Z | -z ] [ -v <em>verbosity</em> ] [ -K kimeout ] [ -k snilevel ] [ -- ] <em>prog...</em>
+     s6-ucspitlsd [ -S | -s ] [ -J | -j ] [ -Y | -y ] [ -Z | -z ] [ -v <em>verbosity</em> ] [ -K kimeout ] [ -k snilevel ] [ -- ] <em>prog...</em>
 </pre>
 
 <ul>
@@ -146,6 +146,9 @@ before execing <em>prog...</em>. This is the default. </li>
 and break the connection when <em>prog</em> sends EOF. </li>
  <li> <tt>-s</tt>&nbsp;: transmit EOF by half-closing the TCP
 connection without using <tt>close_notify</tt>. This is the default. </li>
+ <li> <tt>-J</tt>&nbsp;: make <a href="s6-tlsd-io.html">s6-tlsd-io</a>
+exit with a nonzero code if the peer sends EOF without a close_notify first </li>
+ <li> <tt>-j</tt>&nbsp;: treat EOF from the peer as a normal exit condition </li>
  <li> <tt>-Y</tt>&nbsp;: Request an optional client certificate. </li>
  <li> <tt>-y</tt>&nbsp;: Request a mandatory client certificate.
 The default, with neither the <tt>-Y</tt> nor the <tt>-y</tt> option,
diff --git a/src/include/s6-networking/stls.h b/src/include/s6-networking/stls.h
index e9f6136..2eefe36 100644
--- a/src/include/s6-networking/stls.h
+++ b/src/include/s6-networking/stls.h
@@ -8,15 +8,16 @@
 #include <tls.h>
 
 #include <skalibs/gccattributes.h>
+#include <skalibs/buffer.h>
 #include <skalibs/tai.h>
 
-#define STLS_BUFSIZE (16384 + 325 + 1)
+#define STLS_BUFSIZE 16384
 
 
  /* Engine */
 
 extern int stls_send_environment (struct tls *, int) ;
-extern void stls_run (struct tls *, int *, uint32_t, unsigned int) gccattr_noreturn ;
+extern void stls_run (struct tls *, int const *, uint32_t, unsigned int) gccattr_noreturn ;
 
 
  /* s6-tlsc-io and s6-tlsd-io */
diff --git a/src/sbearssl/sbearssl_run.c b/src/sbearssl/sbearssl_run.c
index 51263ca..d339b69 100644
--- a/src/sbearssl/sbearssl_run.c
+++ b/src/sbearssl/sbearssl_run.c
@@ -68,14 +68,9 @@ void sbearssl_run (br_ssl_engine_context *ctx, int const *fds, tain const *tto,
     }
     else x[0].events = 0 ;
 
-    if (x[1].fd >= 0)
-      x[1].events = IOPAUSE_EXCEPT | (state & BR_SSL_RECVAPP ? IOPAUSE_WRITE : 0) ;
-
-    if (x[2].fd >= 0 && state & BR_SSL_RECVREC) x[2].events = IOPAUSE_READ ;
-    else x[2].events = 0 ;
-
-    if (x[3].fd >= 0)
-      x[3].events = IOPAUSE_EXCEPT | (state & BR_SSL_SENDREC ? IOPAUSE_WRITE : 0) ;
+    x[1].events = x[1].fd >= 0 ? IOPAUSE_EXCEPT | (state & BR_SSL_RECVAPP ? IOPAUSE_WRITE : 0) : 0 ;
+    x[2].events = x[2].fd >= 0 && state & BR_SSL_RECVREC) ? IOPAUSE_READ : 0 ;
+    x[3].events = x[3].fd >= 0 ? IOPAUSE_EXCEPT | (state & BR_SSL_SENDREC ? IOPAUSE_WRITE : 0) : 0 ;
 
 
    /* Wait for events */
@@ -187,6 +182,8 @@ void sbearssl_run (br_ssl_engine_context *ctx, int const *fds, tain const *tto,
         }
         else if (!r)
         {
+          if (handshake_done && options & 2)
+            strerr_dief1x(98, "remote closed connection without a close_notify") ;
           fd_shutdown(x[2].fd, 0) ;
           fd_close(x[2].fd) ;
           x[2].fd = -1 ;
diff --git a/src/stls/stls_client_init_and_handshake.c b/src/stls/stls_client_init_and_handshake.c
index b65c833..6f0e248 100644
--- a/src/stls/stls_client_init_and_handshake.c
+++ b/src/stls/stls_client_init_and_handshake.c
@@ -50,7 +50,7 @@ struct tls *stls_client_init_and_handshake (int const *fds, tain const *tto, uin
     {
       if (tls_config_set_ca_path(cfg, x) < 0)
         diecfg(cfg, "tls_config_set_ca_path") ;
-      strerr_warnw1x("some versions of libtls do not work with CADIR, try using CAFILE instead") ;
+      strerr_warnw1x("some versions of libtls do not work with CADIR, if you experience problems with server certificate verification then try using CAFILE instead") ;
     }
     else strerr_diefu1x(100, "get trust anchor list: neither CADIR nor CAFILE is set") ;
   }
@@ -73,7 +73,7 @@ struct tls *stls_client_init_and_handshake (int const *fds, tain const *tto, uin
   if (!ctx) strerr_diefu1sys(111, "tls_client") ;
   if (tls_configure(ctx, cfg) < 0) diectx(97, ctx, "tls_configure") ;
 
-  if (tls_connect_fds(ctx, fds[0], fds[1], servername) < 0)
+  if (tls_connect_fds(ctx, fds[0], fds[1], servername) == -1)
     diectx(97, ctx, "tls_connect_fds") ;
   tls_config_free(cfg) ;
   stls_handshake(ctx, tto) ;
diff --git a/src/stls/stls_run.c b/src/stls/stls_run.c
index 7385c4e..2456e22 100644
--- a/src/stls/stls_run.c
+++ b/src/stls/stls_run.c
@@ -1,6 +1,7 @@
 /* ISC license. */
 
 #include <sys/uio.h>
+#include <stdint.h>
 #include <errno.h>
 #include <unistd.h>
 
@@ -14,248 +15,259 @@
 
 #include <s6-networking/stls.h>
 
-typedef struct tlsbuf_s tlsbuf_t, *tlsbuf_t_ref ;
-struct tlsbuf_s
+
+typedef struct stls_buffer_s stls_buffer, *stls_buffer_ref ;
+struct stls_buffer_s
 {
   buffer b ;
-  unsigned char blockedonother : 1 ;
   char buf[STLS_BUFSIZE] ;
+  uint8_t flags ;  /* 0x1: flush/fill wants opposite IO; 0x2: close_notify initiated */
 } ;
 
-static inline int buffer_tls_flush (struct tls *ctx, tlsbuf_t *b)
+
+ /*
+    We need access to the state field of struct tls, which is private.
+    So we fake enough stuff that we get the correct field offset.
+ */
+
+#define TLS_EOF_NO_CLOSE_NOTIFY 1
+
+struct fake_tls_error_s
 {
-  struct iovec v[2] ;
-  ssize_t r, w ;
-  buffer_rpeek(&b[0].b, v) ;
-  r = tls_write(ctx, v[0].iov_base, v[0].iov_len) ;
-  switch (r)
-  {
-    case -1 : return -1 ;
-    case TLS_WANT_POLLIN :
-      if (b[1].blockedonother) strerr_dief1x(101, "TLS deadlock") ;
-      b[0].blockedonother = 1 ;
-    case TLS_WANT_POLLOUT : return 0 ;
-    default : break ;
-  }
-  w = r ;
-  if ((size_t)w == v[0].iov_len && v[1].iov_len)
+  char *msg ;
+  int num ;
+  int tls ;
+} ;
+
+struct fake_tls_s
+{
+  void *config ;
+  void *keypair ;
+  struct fake_tls_error_s error ;
+  uint32_t flags ;
+  uint32_t state ;
+} ;
+
+ /* All because there's no accessor for this in the official libtls API: */
+
+static inline int tls_eof_got_close_notify (struct tls *ctx)
+{
+  return !(((struct fake_tls_s *)ctx)->state & TLS_EOF_NO_CLOSE_NOTIFY) ;
+}
+
+ /* We want tls_read/write to behave l */
+
+static int tls_allwrite (struct tls *ctx, char const *s, size_t len, size_t *w)
+{
+  while (*w < len)
   {
-    r = tls_write(ctx, v[1].iov_base, v[1].iov_len) ;
+    ssize_t r = tls_write(ctx, s + *w, len - *w) ;
     switch (r)
     {
-      case TLS_WANT_POLLIN :
-        if (b[1].blockedonother) strerr_dief1x(101, "TLS deadlock") ;
-        b[0].blockedonother = 1 ;
-      case -1 :
-      case TLS_WANT_POLLOUT :
-        buffer_rseek(&b[0].b, w) ;
-        return 0 ;
+      case -1 : strerr_diefu2x(98, "tls_write: ", tls_error(ctx)) ;
+      case TLS_WANT_POLLIN : return 1 ;
+      case TLS_WANT_POLLOUT : return 0 ;
       default : break ;
     }
-    w += r ;
+    *w += r ;
   }
-  buffer_rseek(&b[0].b, w) ;
-  return 1 ;
+  return 0 ;
 }
 
-static inline int buffer_tls_fill (struct tls *ctx, tlsbuf_t *b)
+static void tls_flush (struct tls *ctx, stls_buffer *b)
 {
   struct iovec v[2] ;
-  ssize_t r, w ;
-  int ok = 1 ;
-  buffer_wpeek(&b[1].b, v) ;
-  r = tls_read(ctx, v[0].iov_base, v[0].iov_len) ;
-  switch (r)
-  {
-    case 0 : return -2 ;
-    case -1 : return -1 ;
-    case TLS_WANT_POLLOUT :
-      if (b[0].blockedonother) strerr_dief1x(101, "TLS deadlock") ;
-      b[1].blockedonother = 1 ;
-    case TLS_WANT_POLLIN : return 0 ;
-    default : break ;
-  }
-  w = r ;
-  if ((size_t)w == v[0].iov_len && v[1].iov_len)
+  size_t w = 0 ;
+  int r ;
+  buffer_rpeek(&b[0].b, v) ;
+  r = tls_allwrite(ctx, v[0].iov_base, v[0].iov_len, &w) ;
+  buffer_rseek(&b[0].b, w) ;
+  if (w < v[0].iov_len || !v[1].iov_len) goto out ;
+  w = 0 ;
+  r = tls_allwrite(ctx, v[1].iov_base, v[1].iov_len, &w) ;
+  buffer_rseek(&b[0].b, w) ;
+ out:
+  if (r) b[1].flags |= 1 ; else b[1].flags &= ~1 ;
+}
+
+static int tls_allread (struct tls *ctx, char *s, size_t len, size_t *w)
+{
+  while (*w < len)
   {
-    r = tls_read(ctx, v[1].iov_base, v[1].iov_len) ;
+    ssize_t r = tls_read(ctx, s + *w, len - *w) ;
     switch (r)
     {
-      case TLS_WANT_POLLOUT :
-        if (b[0].blockedonother) strerr_dief1x(101, "TLS deadlock") ;
-        b[1].blockedonother = 1 ;
-      case -1 :
-      case TLS_WANT_POLLIN :
-        buffer_wseek(&b[1].b, w) ;
-        return 0 ;
-      case 0 : ok = -1 ; errno = EPIPE ;
+      case -1 : strerr_diefu2x(98, "tls_read: ", tls_error(ctx)) ;
+      case 0 : return -1 ;
+      case TLS_WANT_POLLIN : return 0 ;
+      case TLS_WANT_POLLOUT : return 1 ;
       default : break ;
     }
-    w += r ;
+    *w += r ;
   }
-  buffer_wseek(&b[1].b, w) ;
-  return ok ;
+  return 0 ;
 }
 
-static void send_closenotify (struct tls *ctx, int const *fds)
+static int tls_fill (struct tls *ctx, stls_buffer *b)
 {
-  iopause_fd x = { .fd = fds[3], .events = IOPAUSE_WRITE } ;
-  while (tls_close(ctx) == TLS_WANT_POLLOUT)
-    iopause_g(&x, 1, 0) ;
+  struct iovec v[2] ;
+  size_t w = 0 ;
+  int r ;
+  buffer_wpeek(&b[1].b, v) ;
+  r = tls_allread(ctx, v[0].iov_base, v[0].iov_len, &w) ;
+  buffer_wseek(&b[1].b, w) ;
+  if (w < v[0].iov_len || !v[1].iov_len) goto out ;
+  w = 0 ;
+  r = tls_allread(ctx, v[1].iov_base, v[1].iov_len, &w) ;
+  buffer_wseek(&b[1].b, w) ;
+ out:
+  if (r == -1) return 1 ;
+  if (r) b[0].flags |= 1 ; else b[0].flags &= ~1 ;
+  return 0 ;
 }
 
-static void closeit (struct tls *ctx, int *fds, int closenotify)
+static int tls_close_nb (struct tls *ctx, stls_buffer *b)
 {
-  if (!closenotify) fd_shutdown(fds[3], 1) ;
-  else if (fds[2] >= 0) send_closenotify(ctx, fds) ;
-  fd_close(fds[3]) ; fds[3] = -1 ;
+  switch (tls_close(ctx))
+  {
+    case 0 : b[0].flags &= ~2 ; b[1].flags &= ~2 ; b[1].flags |= 4 ; return 1 ;
+    case TLS_WANT_POLLIN : b[0].flags &= ~2 ; b[1].flags |= 2 ; break ;
+    case TLS_WANT_POLLOUT : b[0].flags |= 2 ; b[1].flags &= ~2 ; break ;
+    default : strerr_diefu2x(98, "tls_close: ", tls_error(ctx)) ;
+  }
+  return 0 ;
 }
 
-void stls_run (struct tls *ctx, int *fds, uint32_t options, unsigned int verbosity)
+ /* The engine. */
+
+void stls_run (struct tls *ctx, int const *fds, uint32_t options, unsigned int verbosity)
 {
-  tlsbuf_t b[2] = { { .blockedonother = 0 }, { .blockedonother = 0 } } ;
-  iopause_fd x[4] ;
-  unsigned int xindex[4] ;
-
-  if (ndelay_on(fds[0]) < 0
-   || ndelay_on(fds[1]) < 0
-   || ndelay_on(fds[2]) < 0
-   || ndelay_on(fds[3]) < 0)
+  stls_buffer b[2] =
+  {
+    { .b = BUFFER_INIT(&buffer_read, fds[0], b[0].buf, STLS_BUFSIZE), .flags = 0 },
+    { .b = BUFFER_INIT(&buffer_write, fds[1], b[1].buf, STLS_BUFSIZE), .flags = 0 },
+  } ;
+  iopause_fd x[4] = { { .fd = fds[0] }, { .fd = fds[1] }, { .fd = fds[2] }, { .fd = fds[3] } } ;
+
+  if (ndelay_on(x[0].fd) == -1
+   || ndelay_on(x[1].fd) == -1
+   || ndelay_on(x[2].fd) == -1
+   || ndelay_on(x[3].fd) == -1)
     strerr_diefu1sys(111, "set fds non-blocking") ;
 
-  buffer_init(&b[0].b, &buffer_read, fds[0], b[0].buf, STLS_BUFSIZE) ;
-  buffer_init(&b[1].b, &buffer_write, fds[1], b[1].buf, STLS_BUFSIZE) ;
-
-  for (;;)
+  while (x[0].fd >= 0 || x[1].fd >= 0 || x[3].fd >= 0)
   {
-    unsigned int j = 0 ;
-    int r ;
-
-
-   /* poll() preparation */
-
-    if (fds[0] >= 0 && buffer_isreadable(&b[0].b))
-    {
-      x[j].fd = fds[0] ;
-      x[j].events = IOPAUSE_READ ;
-      xindex[0] = j++ ;
-    }
-    else xindex[0] = 4 ;
-
-    if (fds[1] >= 0 && buffer_iswritable(&b[1].b))
-    {
-      x[j].fd = fds[1] ;
-      x[j].events = IOPAUSE_WRITE ;
-      xindex[1] = j++ ;
-    }
-    else xindex[1] = 4 ;
-
-    if (fds[2] >= 0 && !b[1].blockedonother && buffer_isreadable(&b[1].b))
-    {
-      x[j].fd = fds[2] ;
-      x[j].events = IOPAUSE_READ ;
-      xindex[2] = j++ ;
-    }
-    else xindex[2] = 4 ;
-
-    if (fds[3] >= 0 && !b[0].blockedonother && buffer_iswritable(&b[0].b))
-    {
-      x[j].fd = fds[3] ;
-      x[j].events = IOPAUSE_WRITE ;
-      xindex[3] = j++ ;
-    }
-    else xindex[3] = 4 ;
-
-    if (xindex[0] == 4 && xindex[1] == 4 && xindex[3] == 4) break ;
 
+    x[0].events = x[0].fd >= 0 && buffer_isreadable(&b[0].b) ? IOPAUSE_READ : 0 ;
+    x[1].events = x[1].fd >= 0 && buffer_iswritable(&b[1].b) ? IOPAUSE_WRITE : 0 ;
+    x[2].events = x[2].fd >= 0 && (buffer_isreadable(&b[1].b) || (b[1].flags & 1 && buffer_iswritable(&b[0].b))) ? IOPAUSE_READ : 0 ;
+    x[3].events = x[3].fd >= 0 && (buffer_iswritable(&b[0].b) || (b[0].flags & 1 && buffer_isreadable(&b[1].b))) ? IOPAUSE_WRITE : 0 ;
 
-   /* poll() */
-
-    r = iopause_g(x, j, 0) ;
-    if (r < 0) strerr_diefu1sys(111, "iopause") ;
-    else if (!r) break ;
-
-    while (j--)
-      if (x[j].revents & IOPAUSE_EXCEPT)
-        x[j].revents |= IOPAUSE_READ | IOPAUSE_WRITE ;
-
+    if (iopause_g(x, 4, 0) == -1) strerr_diefu1sys(111, "iopause") ;
 
 
    /* Flush to local */
 
-    if (xindex[1] < 4 && x[xindex[1]].revents & IOPAUSE_WRITE)
+    if (x[1].revents)
     {
-      r = buffer_flush(&b[1].b) ;
-      if (!r && !error_isagain(errno))
+      if (!buffer_flush(&b[1].b))
       {
-        strerr_warnwu1sys("write to application") ;
-        if (fds[2] >= 0)
-        {
-          if (options & 1) fd_shutdown(fds[2], 0) ;
-          fd_close(fds[2]) ; fds[2] = -1 ;
-          xindex[2] = 4 ;
-        }
-        r = 1 ;
+        if (!error_isagain(errno)) strerr_diefu1sys(111, "write to local") ;
       }
-      if (r && fds[2] < 0)
+      else if (x[2].fd == -1)
       {
-        fd_close(fds[1]) ; fds[1] = -1 ;
+        fd_close(x[1].fd) ;
+        x[1].fd = -1 ;
       }
     }
 
 
-   /* Flush to remote */
+   /* Flush to remote: do everything that had TLS_WANT_POLLOUT */
 
-    if (xindex[3] < 4 && x[xindex[3]].revents & IOPAUSE_WRITE)
+    if (x[3].revents)
     {
-      r = buffer_tls_flush(ctx, b) ;
-      if (r < 0)
+      if (buffer_len(&b[0].b)) tls_flush(ctx, b) ;  /* normal write */
+      if ((b[0].flags & 1 && tls_fill(ctx, b))  /* peer sent close_notify and it just completed */
+       || (b[0].flags & 2 && tls_close_nb(ctx, b)))  /*  we send close_notify and it instantly succeeds */
       {
-        strerr_warnwu2x("write to peer: ", tls_error(ctx)) ;
-        fd_close(fds[0]) ; fds[0] = -1 ;
-        xindex[0] = 4 ;
+        if (buffer_isempty(&b[1].b)) break ;
+        fd_close(x[3].fd) ; x[3].fd = -1 ;
+        fd_close(x[2].fd) ; x[2].fd = -1 ;
+        if (x[0].fd >= 0) { fd_close(x[0].fd) ; x[0].fd = -1 ; }
+        continue ;
+      }
+      if (x[0].fd == -1 && buffer_isempty(&b[0].b))
+      {
+        if (!(options & 1) || tls_close_nb(ctx, b))
+        {
+          fd_shutdown(x[3].fd, 1) ;
+          fd_close(x[3].fd) ;
+          x[3].fd = -1 ;
+        }
       }
-      if (r && fds[0] < 0)
-        closeit(ctx, fds, options & 1) ;
     }
 
 
    /* Fill from local */
 
-    if (xindex[0] < 4 && x[xindex[0]].revents & IOPAUSE_READ)
+    if (x[0].revents)
     {
-      r = sanitize_read(buffer_fill(&b[0].b)) ;
-      if (r < 0)
+      ssize_t r = buffer_fill(&b[0].b) ;
+      if (r == -1 && !error_isagain(errno))
+        strerr_diefu1sys(111, "read from local") ;
+      else if (!r)
       {
-        if (errno != EPIPE) strerr_warnwu1sys("read from application") ;
-        fd_close(fds[0]) ; fds[0] = -1 ;
+        fd_close(x[0].fd) ;
+        x[0].fd = -1 ;
         if (buffer_isempty(&b[0].b))
-          closeit(ctx, fds, options & 1) ;
+        {
+          if (!(options & 1) || tls_close_nb(ctx, b))
+          {
+            fd_shutdown(x[3].fd, 1) ;
+            fd_close(x[3].fd) ;
+            x[3].fd = -1 ;
+          }
+        }
       }
     }
 
 
-   /* Fill from remote */
+   /* Fill from remote: do everything that had TLS_WANT_POLLIN */
 
-    if (xindex[2] < 4 && x[xindex[2]].revents & IOPAUSE_READ)
+    if (x[2].revents)
     {
-      r = buffer_tls_fill(ctx, b) ;
-      if (r < 0)
-      {
-        if (r == -1) strerr_warnwu2x("read from peer: ", tls_error(ctx)) ;
-        if (!(options & 1)) fd_shutdown(fds[2], 0) ;
-        /*
-           XXX: We need a way to detect when we've received a close_notify,
-           because then we need to trigger a write and then shut the engine
-           down. This is orthogonal to options&1, it only means that the
-           peer sent a close_notify.
-           As for now, libtls doesn't offer an API to detect that, so we
-           do nothing special - we just wait until our app sends EOF.
-        */
-        fd_close(fds[2]) ; fds[2] = -1 ;
+      if (buffer_isreadable(&b[1].b) && tls_fill(ctx, b))
+      {  /* connection closed */
+        fd_shutdown(x[2].fd, 0) ;
+        fd_close(x[2].fd) ;
+        x[2].fd = -1 ;
         if (buffer_isempty(&b[1].b))
         {
-          fd_close(fds[1]) ; fds[1] = -1 ;
+          if (tls_eof_got_close_notify(ctx)) break ;
+          fd_close(x[1].fd) ;
+          x[1].fd = -1 ;
+        }
+        if (options & 2)
+        {
+          if (!tls_eof_got_close_notify(ctx))
+            strerr_dief1x(98, "remote closed connection without a close_notify") ;
+          else if (x[3].fd >= 0)
+          {
+            fd_shutdown(x[3].fd, 1) ;
+            fd_close(x[3].fd) ;
+            x[3].fd = -1 ;
+          }
+        }
+      }
+      else
+      {  /* normal case */
+        if (b[1].flags & 1) tls_flush(ctx, b) ;
+        if (b[1].flags & 2 && tls_close_nb(ctx, b))
+        {
+          if (buffer_isempty(&b[1].b)) break ;
+          if (x[3].fd >= 0) { fd_close(x[3].fd) ; x[3].fd = -1 ; }
+          if (x[0].fd >= 0) { fd_close(x[0].fd) ; x[0].fd = -1 ; }
+          fd_close(x[2].fd) ; x[2].fd = -1 ;
         }
       }
     }
diff --git a/src/stls/stls_server_init_and_handshake.c b/src/stls/stls_server_init_and_handshake.c
index 2304598..2a58885 100644
--- a/src/stls/stls_server_init_and_handshake.c
+++ b/src/stls/stls_server_init_and_handshake.c
@@ -86,6 +86,7 @@ struct tls *stls_server_init_and_handshake (int const *fds, tain const *tto, uin
     {
       if (tls_config_set_ca_path(cfg, x) < 0)
         diecfg(cfg, "tls_config_set_ca_path") ;
+      strerr_warnw1x("some versions of libtls do not work with CADIR, if you experience problems with client certificate verification then try using CAFILE instead") ;
     }
     else
     {
@@ -109,7 +110,7 @@ struct tls *stls_server_init_and_handshake (int const *fds, tain const *tto, uin
   if (!sctx) strerr_diefu1sys(111, "tls_server") ;
   if (tls_configure(sctx, cfg) < 0) diectx(97, sctx, "tls_configure") ;
   tls_config_free(cfg) ;
-  if (tls_accept_fds(sctx, &ctx, fds[0], fds[1]) < 0)
+  if (tls_accept_fds(sctx, &ctx, fds[0], fds[1]) == -1)
     diectx(97, sctx, "tls_accept_fds") ;
   /* We can't free sctx, ctx has pointers into it! Stupid API. We let sctx leak. */
   /* tls_free(sctx) ; */
diff --git a/src/tls/s6-tlsc-io.c b/src/tls/s6-tlsc-io.c
index e64c014..25347b7 100644
--- a/src/tls/s6-tlsc-io.c
+++ b/src/tls/s6-tlsc-io.c
@@ -13,7 +13,7 @@
 
 #include <s6-networking/config.h>
 
-#define USAGE "s6-tlsc-io [ -v verbosity ] [ -d notif ] [ -S | -s ] [ -Y | -y ] [ -K timeout ] [ -k servername ] fdr fdw"
+#define USAGE "s6-tlsc-io [ -v verbosity ] [ -d notif ] [ -S | -s ] [ -J | -j ] [ -Y | -y ] [ -K timeout ] [ -k servername ] fdr fdw"
 #define dieusage() strerr_dieusage(100, USAGE)
 
 static inline void doit (int *, tain const *tto, uint32_t, uint32_t, unsigned int, char const *, unsigned int) gccattr_noreturn ;
@@ -81,7 +81,7 @@ int main (int argc, char const *const *argv, char const *const *envp)
     unsigned int t = 0 ;
     for (;;)
     {
-      int opt = subgetopt_r(argc, argv, "d:SsYyv:K:k:", &l) ;
+      int opt = subgetopt_r(argc, argv, "d:SsJjYyv:K:k:", &l) ;
       if (opt == -1) break ;
       switch (opt)
       {
@@ -89,8 +89,10 @@ int main (int argc, char const *const *argv, char const *const *envp)
         case 'd' : if (!uint0_scan(l.arg, &notif)) dieusage() ; break ;
         case 'S' : options |= 1 ; break ;
         case 's' : options &= ~1 ; break ;
-        case 'Y' : preoptions &= ~1 ; break ;
+        case 'J' : options |= 2 ; break ;
+        case 'j' : options &= ~2 ; break ;
         case 'y' : preoptions |= 1 ; break ;
+        case 'Y' : preoptions &= ~1 ; break ;
         case 'K' : if (!uint0_scan(l.arg, &t)) dieusage() ; break ;
         case 'k' : servername = l.arg ; break ;
         default : dieusage() ;
diff --git a/src/tls/s6-tlsc.c b/src/tls/s6-tlsc.c
index d348599..ebea264 100644
--- a/src/tls/s6-tlsc.c
+++ b/src/tls/s6-tlsc.c
@@ -11,7 +11,7 @@
 
 #include "s6tls-internal.h"
 
-#define USAGE "s6-tlsc [ -S | -s ]  [ -Y | -y ] [ -v verbosity ] [ -K timeout ] [ -k servername ] [ -Z | -z ] [ -6 fdr ] [ -7 fdw ] prog..."
+#define USAGE "s6-tlsc [ -S | -s ] [ -J | -j ] [ -Y | -y ] [ -v verbosity ] [ -K timeout ] [ -k servername ] [ -Z | -z ] [ -6 fdr ] [ -7 fdw ] prog..."
 #define dieusage() strerr_dieusage(100, USAGE)
 
 int main (int argc, char const *const *argv)
@@ -30,14 +30,16 @@ int main (int argc, char const *const *argv)
     subgetopt l = SUBGETOPT_ZERO ;
     for (;;)
     {
-      int opt = subgetopt_r(argc, argv, "SsYyv:K:k:Zz6:7:", &l) ;
+      int opt = subgetopt_r(argc, argv, "SsJjyYv:K:k:Zz6:7:", &l) ;
       if (opt == -1) break ;
       switch (opt)
       {
-        case 'S' : coptions &= ~4 ; break ;
-        case 's' : coptions |= 4 ; break ;
-        case 'Y' : coptions &= ~1 ; break ;
+        case 'S' : coptions |= 4 ; break ;
+        case 's' : coptions &= ~4 ; break ;
+        case 'J' : coptions |= 2 ; break ;
+        case 'j' : coptions &= ~2 ; break ;
         case 'y' : coptions |= 1 ; break ;
+        case 'Y' : coptions &= ~1 ; break ;
         case 'v' : if (!uint0_scan(l.arg, &verbosity)) dieusage() ; break ;
         case 'K' : if (!uint0_scan(l.arg, &kimeout)) dieusage() ; break ;
         case 'k' : servername = l.arg ; break ;
diff --git a/src/tls/s6-tlsd-io.c b/src/tls/s6-tlsd-io.c
index fac2164..08eee77 100644
--- a/src/tls/s6-tlsd-io.c
+++ b/src/tls/s6-tlsd-io.c
@@ -13,7 +13,7 @@
 
 #include <s6-networking/config.h>
 
-#define USAGE "s6-tlsd-io [ -v verbosity ] [ -d notif ] [ -S | -s ] [ -Y | -y ] [ -K timeout ] [ -k snilevel ] fdr fdw"
+#define USAGE "s6-tlsd-io [ -v verbosity ] [ -d notif ] [ -S | -s ] [ -J | -j ] [ -Y | -y ] [ -K timeout ] [ -k snilevel ] fdr fdw"
 #define dieusage() strerr_dieusage(100, USAGE)
 
 static inline void doit (int *, tain const *tto, uint32_t, uint32_t, unsigned int, unsigned int) gccattr_noreturn ;
@@ -78,7 +78,7 @@ int main (int argc, char const *const *argv)
     unsigned int t = 0 ;
     for (;;)
     {
-      int opt = subgetopt_r(argc, argv, "d:SsYyv:K:k:", &l) ;
+      int opt = subgetopt_r(argc, argv, "d:SsJjYyv:K:k:", &l) ;
       if (opt == -1) break ;
       switch (opt)
       {
@@ -86,6 +86,8 @@ int main (int argc, char const *const *argv)
         case 'd' : if (!uint0_scan(l.arg, &notif)) dieusage() ; break ;
         case 'S' : options |= 1 ; break ;
         case 's' : options &= ~1 ; break ;
+        case 'J' : options |= 2 ; break ;
+        case 'j' : options &= ~2 ; break ;
         case 'Y' : preoptions |= 1 ; preoptions &= ~2 ; break ;
         case 'y' : preoptions |= 3 ; break ;
         case 'K' : if (!uint0_scan(l.arg, &t)) dieusage() ; break ;
diff --git a/src/tls/s6-tlsd.c b/src/tls/s6-tlsd.c
index 85c0d9f..acd2945 100644
--- a/src/tls/s6-tlsd.c
+++ b/src/tls/s6-tlsd.c
@@ -9,7 +9,7 @@
 
 #include "s6tls-internal.h"
 
-#define USAGE "s6-tlsd [ -S | -s ] [ -Y | -y ] [ -k snilevel ] [ -v verbosity ] [ -K timeout ] [ -Z | -z ] prog..."
+#define USAGE "s6-tlsd [ -S | -s ] [ -J | -j ] [ -Y | -y ] [ -k snilevel ] [ -v verbosity ] [ -K timeout ] [ -Z | -z ] prog..."
 #define dieusage() strerr_dieusage(100, USAGE)
 
 int main (int argc, char const *const *argv)
@@ -28,14 +28,16 @@ int main (int argc, char const *const *argv)
     subgetopt l = SUBGETOPT_ZERO ;
     for (;;)
     {
-      int opt = subgetopt_r(argc, argv, "SsYyv:K:Zzk:", &l) ;
+      int opt = subgetopt_r(argc, argv, "SsJjyYv:K:Zzk:", &l) ;
       if (opt == -1) break ;
       switch (opt)
       {
         case 'S' : coptions |= 4 ; break ;
         case 's' : coptions &= ~4 ; break ;
-        case 'Y' : coptions |= 1 ; coptions &= ~2 ; break ;
+        case 'J' : coptions |= 8 ; break ;
+        case 'j' : coptions &= ~8 ; break ;
         case 'y' : coptions |= 3 ; break ;
+        case 'Y' : coptions |= 1 ; coptions &= ~2 ; break ;
         case 'v' : if (!uint0_scan(l.arg, &verbosity)) dieusage() ; break ;
         case 'K' : if (!uint0_scan(l.arg, &kimeout)) dieusage() ; break ;
         case 'Z' : poptions &= ~1 ; break ;
diff --git a/src/tls/s6-ucspitlsc.c b/src/tls/s6-ucspitlsc.c
index bb1a2dc..cd29324 100644
--- a/src/tls/s6-ucspitlsc.c
+++ b/src/tls/s6-ucspitlsc.c
@@ -15,7 +15,7 @@
 #include <s6-networking/config.h>
 #include "s6tls-internal.h"
 
-#define USAGE "s6-ucspitlsc [ -S | -s ] [ -Y | -y ] [ -v verbosity ] [ -K timeout ] [ -Z | -z ] [ -k servername ] [ -6 fdr ] [ -7 fdw ] prog..."
+#define USAGE "s6-ucspitlsc [ -S | -s ] [ -J | -j ] [ -Y | -y ] [ -v verbosity ] [ -K timeout ] [ -Z | -z ] [ -k servername ] [ -6 fdr ] [ -7 fdw ] prog..."
 #define dieusage() strerr_dieusage(100, USAGE)
 
 static inline void child (int *, uint32_t, unsigned int, unsigned int, char const *, pid_t) gccattr_noreturn ;
@@ -80,14 +80,16 @@ int main (int argc, char const *const *argv, char const *const *envp)
     subgetopt l = SUBGETOPT_ZERO ;
     for (;;)
     {
-      int opt = subgetopt_r(argc, argv, "SsYyv:K:Zzk:6:7:", &l) ;
+      int opt = subgetopt_r(argc, argv, "SsJjyYv:K:Zzk:6:7:", &l) ;
       if (opt == -1) break ;
       switch (opt)
       {
         case 'S' : coptions |= 4 ; break ;
         case 's' : coptions &= ~4 ; break ;
-        case 'Y' : coptions |= 1 ; coptions &= ~2 ; break ;
-        case 'y' : coptions |= 3 ; break ;
+        case 'J' : coptions |= 2 ; break ;
+        case 'j' : coptions &= ~2 ; break ;
+        case 'y' : coptions |= 1 ; break ;
+        case 'Y' : coptions &= ~1 ; break ;
         case 'v' : if (!uint0_scan(l.arg, &verbosity)) dieusage() ; break ;
         case 'K' : if (!uint0_scan(l.arg, &kimeout)) dieusage() ; break ;
         case 'Z' : poptions &= ~1 ; break ;
diff --git a/src/tls/s6-ucspitlsd.c b/src/tls/s6-ucspitlsd.c
index fc0868a..d2b9580 100644
--- a/src/tls/s6-ucspitlsd.c
+++ b/src/tls/s6-ucspitlsd.c
@@ -14,7 +14,7 @@
 #include <s6-networking/config.h>
 #include "s6tls-internal.h"
 
-#define USAGE "s6-ucspitlsd [ -S | -s ] [ -Y | -y ] [ -k snilevel ] [ -v verbosity ] [ -K timeout ] [ -Z | -z ] prog..."
+#define USAGE "s6-ucspitlsd [ -S | -s ] [ -J | -j ] [ -Y | -y ] [ -k snilevel ] [ -v verbosity ] [ -K timeout ] [ -Z | -z ] prog..."
 #define dieusage() strerr_dieusage(100, USAGE)
 
 static inline void child (int *, uint32_t, unsigned int, unsigned int, unsigned int, pid_t) gccattr_noreturn ;
@@ -77,14 +77,16 @@ int main (int argc, char const *const *argv)
     subgetopt l = SUBGETOPT_ZERO ;
     for (;;)
     {
-      int opt = subgetopt_r(argc, argv, "SsYyv:K:Zzk:", &l) ;
+      int opt = subgetopt_r(argc, argv, "SsJjyYv:K:Zzk:", &l) ;
       if (opt == -1) break ;
       switch (opt)
       {
         case 'S' : coptions |= 4 ; break ;
         case 's' : coptions &= ~4 ; break ;
-        case 'Y' : coptions |= 1 ; coptions &= ~2 ; break ;
+        case 'J' : coptions |= 8 ; break ;
+        case 'j' : coptions &= ~8 ; break ;
         case 'y' : coptions |= 3 ; break ;
+        case 'Y' : coptions |= 1 ; coptions &= ~2 ; break ;
         case 'v' : if (!uint0_scan(l.arg, &verbosity)) dieusage() ; break ;
         case 'K' : if (!uint0_scan(l.arg, &kimeout)) dieusage() ; break ;
         case 'Z' : poptions &= ~1 ; break ;
diff --git a/src/tls/s6tls-internal.h b/src/tls/s6tls-internal.h
index fdd247f..1ab77f6 100644
--- a/src/tls/s6tls-internal.h
+++ b/src/tls/s6tls-internal.h
@@ -9,7 +9,7 @@
 #include <skalibs/gccattributes.h>
 #include <skalibs/types.h>
 
-#define S6TLS_PREP_IO_ARGC 15
+#define S6TLS_PREP_IO_ARGC 16
 #define S6TLS_PREP_IO_BUFLEN (5 * UINT_FMT)
 
 extern pid_t s6tls_io_spawn (char const *const *argv, int const *, int) ;
diff --git a/src/tls/s6tls_prep_tlscio.c b/src/tls/s6tls_prep_tlscio.c
index a3f33b0..0b7ff1f 100644
--- a/src/tls/s6tls_prep_tlscio.c
+++ b/src/tls/s6tls_prep_tlscio.c
@@ -26,6 +26,7 @@ void s6tls_prep_tlscio (char const **argv, char *buf, int const *p, uint32_t opt
     buf[n++] = 0 ;
   }
   argv[m++] = options & 4 ? "-S" : "-s" ;
+  argv[m++] = options & 2 ? "-J" : "-j" ;
   argv[m++] = options & 1 ? "-y" : "-Y" ;
   if (kimeout)
   {
diff --git a/src/tls/s6tls_prep_tlsdio.c b/src/tls/s6tls_prep_tlsdio.c
index 73099bf..59cc536 100644
--- a/src/tls/s6tls_prep_tlsdio.c
+++ b/src/tls/s6tls_prep_tlsdio.c
@@ -26,6 +26,7 @@ void s6tls_prep_tlsdio (char const **argv, char *buf, int const *p, uint32_t opt
     buf[n++] = 0 ;
   }
   argv[m++] = options & 4 ? "-S" : "-s" ;
+  argv[m++] = options & 8 ? "-J" : "-j" ;
   if (options & 1)
     argv[m++] = options & 2 ? "-y" : "-Y" ;
   if (kimeout)