From f4db5740c56f3b29b11a796147086ec8848a7e90 Mon Sep 17 00:00:00 2001
From: Jeremy Harris <jgh146exb@wizmail.org>
Date: Thu, 15 Aug 2024 14:53:22 +0100
Subject: [PATCH] transport dynamic modules

---
 doc/doc-docbook/spec.xfpt                     |   3 +-
 doc/doc-txt/NewStuff                          |   4 +-
 src/scripts/Configure-Makefile                |  17 +-
 src/scripts/MakeLinks                         |   3 +-
 .../{routers-Makefile => drivers-Makefile}    |  60 +++--
 src/src/EDITME                                |   9 +
 src/src/drtables.c                            | 215 +++++-------------
 src/src/globals.h                             |   7 +-
 src/src/route.c                               |   1 -
 src/src/routers/Makefile                      |   2 +-
 src/src/transport.c                           |  55 +++--
 src/src/transports/Makefile                   |  50 +++-
 src/src/transports/appendfile.c               |  25 ++
 src/src/transports/autoreply.c                |  25 ++
 src/src/transports/lmtp.c                     |  25 ++
 src/src/transports/pipe.c                     |  25 ++
 src/src/transports/queuefile.c                |  25 ++
 src/src/transports/smtp.c                     |  25 ++
 test/confs/0000                               |   1 +
 test/runtest                                  |  10 +-
 20 files changed, 360 insertions(+), 227 deletions(-)
 rename src/scripts/{routers-Makefile => drivers-Makefile} (72%)

diff --git a/doc/doc-docbook/spec.xfpt b/doc/doc-docbook/spec.xfpt
index 84597da83..9fbf7a2db 100644
--- a/doc/doc-docbook/spec.xfpt
+++ b/doc/doc-docbook/spec.xfpt
@@ -2072,6 +2072,7 @@ withdrawn.
 .section "Dynamically loaded module support" "SECTdynamicmodules"
 .cindex "lookup modules"
 .cindex "router modules"
+.cindex "transport modules"
 .cindex "dynamic modules"
 .cindex ".so building"
 On some platforms, Exim supports not compiling all lookup types directly into
@@ -2083,7 +2084,7 @@ dependencies.
 Most, but not all, lookup types can be built this way.
 
 .new
-Similarly, router drivers can be built as external modules.
+Similarly, router and transport drivers can be built as external modules.
 This permits a smaller exim binary, growing only as needed for the
 runtime cofiguration.
 .wen
diff --git a/doc/doc-txt/NewStuff b/doc/doc-txt/NewStuff
index bb7f2290e..be0f0c679 100644
--- a/doc/doc-txt/NewStuff
+++ b/doc/doc-txt/NewStuff
@@ -14,8 +14,8 @@ Version 4.98
 
  3. Events smtp:fail:protocol and smtp:fail:syntax
 
- 4. JSON lookup support, and all the router driver except manualroute,
-    can now be built as lodable modules
+ 4. JSON lookup support, all the router drivers except manualroute, and all the transport
+    drivers except smtp can now be built as lodable modules
 
 Version 4.98
 ------------
diff --git a/src/scripts/Configure-Makefile b/src/scripts/Configure-Makefile
index 3b0528940..20e686b51 100755
--- a/src/scripts/Configure-Makefile
+++ b/src/scripts/Configure-Makefile
@@ -10,6 +10,7 @@
 
 LC_ALL=C
 export LC_ALL
+set -e
 
 
 # First off, get the OS type, and check that there is a make file for it.
@@ -291,12 +292,16 @@ rm -f $mftt
 cp ../src/lookups/Makefile $look_mf_pre
 ../scripts/lookups-Makefile
 
-class="routers"
-cp ../src/$class/Makefile $class/Makefile.predynamic
-../scripts/$class-Makefile
-mv routers/Makefile.postdynamic $class/Makefile
-rm $class/Makefile.predynamic
-class=
+while read class classdef names
+do
+  cp ../src/$class/Makefile $class/Makefile.predynamic
+  CLASS=$class CLASSDEF=$classdef DRNAMES="$names" ../scripts/drivers-Makefile
+  mv $class/Makefile.postdynamic $class/Makefile
+  rm $class/Makefile.predynamic
+done <<-END
+ routers ROUTER		ACCEPT DNSLOOKUP IPLITERAL IPLOOKUP MANUALROUTE QUERYPROGRAM REDIRECT
+ transports TRANSPORT	APPENDFILE AUTOREPLY LMTP PIPE QUEUEFILE SMTP
+END
 
 # See if there is a definition of EXIM_PERL in what we have built so far.
 # If so, run Perl to find the default values for PERL_CC, PERL_CCOPTS,
diff --git a/src/scripts/MakeLinks b/src/scripts/MakeLinks
index f413c625e..998b73bf9 100755
--- a/src/scripts/MakeLinks
+++ b/src/scripts/MakeLinks
@@ -63,7 +63,8 @@ cd ..
 d="transports"
 mkdir $d
 cd $d
-for f in README Makefile appendfile.h appendfile.c autoreply.h \
+# Makefile is generated
+for f in README appendfile.h appendfile.c autoreply.h \
   autoreply.c lmtp.h lmtp.c pipe.h pipe.c queuefile.c queuefile.h \
   smtp.h smtp.c smtp_socks.c tf_maildir.c tf_maildir.h
 do
diff --git a/src/scripts/routers-Makefile b/src/scripts/drivers-Makefile
similarity index 72%
rename from src/scripts/routers-Makefile
rename to src/scripts/drivers-Makefile
index 5bb6a78d8..0c3da19cb 100755
--- a/src/scripts/routers-Makefile
+++ b/src/scripts/drivers-Makefile
@@ -1,17 +1,23 @@
 #! /bin/sh
 
-# Copyright (c) The Exim Maintainers 1995 - 2021
+# Copyright (c) The Exim Maintainers 1995 - 2024
 # SPDX-License-Identifier: GPL-2.0-or-later
 
-# We turn the configure-built build-$foo/routers/Makefile.predynamic into Makefile
+set -e
+class=${CLASS:?}
+classdef=${CLASSDEF:?}
+drnames="${DRNAMES:?}"
+
+# We turn the configure-built build-$foo/$class/Makefile.predynamic into Makefile.
+# This is used for router and transport drivers, called from scripts/Configure-Makefile.
 
 # We always re-exec ourselves at least once, because it's the cleanest and
 # most portable way to turn on various features we expect of POSIX sh.
-if [ -z "$EXIM_ROUTER_MAKEFILE_ADJUSTED" ]
+if [ -z "$EXIM_DRIVER_MAKEFILE_ADJUSTED" ]
 then
   SHELL=/bin/sh
-  EXIM_ROUTER_MAKEFILE_ADJUSTED=yes
-  export EXIM_ROUTER_MAKEFILE_ADJUSTED
+  EXIM_DRIVER_MAKEFILE_ADJUSTED=yes
+  export EXIM_DRIVER_MAKEFILE_ADJUSTED
 
   # Solaris sh and tr are problematic until we get xpg4 variants
   if [ -x /usr/xpg4/bin/sh ]
@@ -46,8 +52,8 @@ then
   exec "$SHELL" "$0" "$@"
 fi
 
-input=routers/Makefile.predynamic
-target=routers/Makefile.postdynamic
+input=$class/Makefile.predynamic
+target=$class/Makefile.postdynamic
 defs_source=Makefile-t
 tag_marker='MAGIC-TAG-MODS-OBJ-RULES-GO-HERE'
 
@@ -76,10 +82,10 @@ fi
 if grep -q "^CFLAGS_DYNAMIC[ $tab?:]*=" "$defs_source"
 then
   # we have a definition, we're good to go
-  echo >&2 ">>> Creating routers/Makefile for building dynamic modules"
+  echo >&2 ">>> Creating $class/Makefile for building dynamic modules"
   enable_dynamic=yes
 else
-  echo >&2 ">>> Creating routers/Makefile without dynamic module support"
+  echo >&2 ">>> Creating $class/Makefile without dynamic module support"
   enable_dynamic=''
   # We always do something now, since there should always be a lookup,
   # and now we need to run in order to put the OBJ=$(OBJ)+ rules in.  So we
@@ -91,27 +97,18 @@ fi
 
 want_dynamic() {
   local dyn_name="$1"
-  local re="ROUTER_${dyn_name}[ $tab]*=[ $tab]*2"
-  env | grep -q "^$re"
+  local re="(${classdef}|EXPERIMENTAL)_${dyn_name}[ $tab]*=[ $tab]*2"
+  env | grep -E -q "^$re"
   if [ $? -eq 0 ]; then return 0; fi
-  grep -q "^[ $tab]*$re" "$defs_source"
+  grep -E -q "^[ $tab]*$re" "$defs_source"
 }
 
 want_at_all() {
   local want_name="$1"
-  local re="ROUTER_${want_name}[ $tab]*=[ $tab]*."
-  env | grep -q "^$re"
-  if [ $? -eq 0 ]; then return 0; fi
-  grep -q "^[ $tab]*$re" "$defs_source"
-}
-
-# Adapted want_at_all above to work for EXPERIMENTAL features
-want_experimental() {
-  local want_name="$1"
-  local re="EXPERIMENTAL_${want_name}[ $tab]*=[ $tab]*."
-  env | grep -q "^$re"
+  local re="(${classdef}|EXPERIMENTAL)_${want_name}[ $tab]*=[ $tab]*."
+  env | grep -E -q "^$re"
   if [ $? -eq 0 ]; then return 0; fi
-  grep -q "^[ $tab]*$re" "$defs_source"
+  grep -E -q "^[ $tab]*$re" "$defs_source"
 }
 
 # The values of these variables will be emitted into the Makefile.
@@ -140,15 +137,15 @@ emit_module_rule() {
       exit 1
     fi
     MODS="${MODS} ${mod_name}.so"
-#    pkgconf=$(grep "^ROUTER_${name}_PC" "$defs_source")
+#    pkgconf=$(grep "^${classdef}_${name}_PC" "$defs_source")
 #    if [ $? -eq 0 ]; then
 #      pkgconf=$(echo $pkgconf | sed 's/^.*= *//')
-#      echo "ROUTER_${mod_name}_INCLUDE = $(pkg-config --cflags $pkgconf)"
-#      echo "ROUTER_${mod_name}_LIBS = $(pkg-config --libs $pkgconf)"
+#      echo "${classdef}_${mod_name}_INCLUDE = $(pkg-config --cflags $pkgconf)"
+#      echo "${classdef}_${mod_name}_LIBS = $(pkg-config --libs $pkgconf)"
 #    else
-#      grep "^ROUTER_${name}_" "$defs_source"
-#      echo "ROUTER_${mod_name}_INCLUDE = \$(ROUTER_${name}_INCLUDE)"
-#      echo "ROUTER_${mod_name}_LIBS = \$(ROUTER_${name}_LIBS)"
+#      grep "^${classdef}_${name}_" "$defs_source"
+#      echo "${classdef}_${mod_name}_INCLUDE = \$(${classdef}_${name}_INCLUDE)"
+#      echo "${classdef}_${mod_name}_LIBS = \$(${classdef}_${name}_LIBS)"
 #    fi
   elif want_at_all "$name"
   then
@@ -162,8 +159,7 @@ exec > "$target"
 
 sed -n "1,/$tag_marker/p" < "$input"
 
-for name_mod in \
-    ACCEPT DNSLOOKUP IPLITERAL IPLOOKUP MANUALROUTE QUERYPROGRAM REDIRECT
+for name_mod in $drnames
 do
   emit_module_rule $name_mod
 done
diff --git a/src/src/EDITME b/src/src/EDITME
index 5e755692f..820793032 100644
--- a/src/src/EDITME
+++ b/src/src/EDITME
@@ -344,6 +344,15 @@ ROUTER_REDIRECT=yes
 # file. By commenting out those you know you don't want to use, you can make
 # the binary a bit smaller. If you are unsure, leave all of these included for
 # now.
+#
+# If set to "2" instead of "yes" then the corresponding driver will be
+# built as a module and must be installed into LOOKUP_MODULE_DIR (the name
+# is historic).
+# You need to add -export-dynamic -rdynamic to EXTRALIBS. You may also need to
+# add -ldl to EXTRALIBS so that dlopen() is available to Exim. You need to
+# define CFLAGS_DYNAIC and LOOKUP_MODULE_DIR below so the builds are done right,
+# and so the exim binary actually loads dynamic lookup modules.
+# The smtp transport cannot be built as a module.
 
 TRANSPORT_APPENDFILE=yes
 TRANSPORT_AUTOREPLY=yes
diff --git a/src/src/drtables.c b/src/src/drtables.c
index b51409096..026f2ff97 100644
--- a/src/src/drtables.c
+++ b/src/src/drtables.c
@@ -230,134 +230,11 @@ exim binary. */
 
 #include "routers/rf_functions.h"
 
-#ifdef TRANSPORT_APPENDFILE
-# include "transports/appendfile.h"
-#endif
-
-#ifdef TRANSPORT_AUTOREPLY
-# include "transports/autoreply.h"
-#endif
-
-#ifdef TRANSPORT_LMTP
-# include "transports/lmtp.h"
-#endif
-
-#ifdef TRANSPORT_PIPE
-# include "transports/pipe.h"
-#endif
-
-#ifdef EXPERIMENTAL_QUEUEFILE
-# include "transports/queuefile.h"
-#endif
-
-#ifdef TRANSPORT_SMTP
-# include "transports/smtp.h"
-#endif
-
 
 router_info * routers_available = NULL;
+transport_info * transports_available = NULL;
 
 
-transport_info * transports_available_newlist = NULL;
-transport_info transports_available_oldarray[] = {
-#ifdef TRANSPORT_APPENDFILE
-  {
-  .drinfo = {
-    .driver_name =	US"appendfile",
-    .options =		appendfile_transport_options,
-    .options_count =	&appendfile_transport_options_count,
-    .options_block =	&appendfile_transport_option_defaults,       /* private options defaults */
-    .options_len =	sizeof(appendfile_transport_options_block),
-    .init =		appendfile_transport_init,
-    },
-  .code =		appendfile_transport_entry,
-  .tidyup =		NULL,
-  .closedown =		NULL,
-  .local =		TRUE
-  },
-#endif
-#ifdef TRANSPORT_AUTOREPLY
-  {
-  .drinfo = {
-    .driver_name =	US"autoreply",
-    .options =		autoreply_transport_options,
-    .options_count =	&autoreply_transport_options_count,
-    .options_block =	&autoreply_transport_option_defaults,
-    .options_len =	sizeof(autoreply_transport_options_block),
-    .init =		autoreply_transport_init,
-    },
-  .code =		autoreply_transport_entry,
-  .tidyup =		NULL,
-  .closedown =		NULL,
-  .local =		TRUE
-  },
-#endif
-#ifdef TRANSPORT_LMTP
-  {
-  .drinfo = {
-    .driver_name =	US"lmtp",
-    .options =		lmtp_transport_options,
-    .options_count =	&lmtp_transport_options_count,
-    .options_block =	&lmtp_transport_option_defaults,
-    .options_len =	sizeof(lmtp_transport_options_block),
-    .init =		lmtp_transport_init,
-    },
-  .code =		lmtp_transport_entry,
-  .tidyup =		NULL,
-  .closedown =		NULL,
-  .local =		TRUE
-  },
-#endif
-#ifdef TRANSPORT_PIPE
-  {
-  .drinfo = {
-    .driver_name =	US"pipe",
-    .options =		pipe_transport_options,
-    .options_count =	&pipe_transport_options_count,
-    .options_block =	&pipe_transport_option_defaults,
-    .options_len =	sizeof(pipe_transport_options_block),
-    .init =		pipe_transport_init,
-    },
-  .code =		pipe_transport_entry,
-  .tidyup =		NULL,
-  .closedown =		NULL,
-  .local =		TRUE
-  },
-#endif
-#ifdef EXPERIMENTAL_QUEUEFILE
-  {
-  .drinfo = {
-    .driver_name =	US"queuefile",
-    .options =		queuefile_transport_options,
-    .options_count =	&queuefile_transport_options_count,
-    .options_block =	&queuefile_transport_option_defaults,
-    .options_len =	sizeof(queuefile_transport_options_block),
-    .init =		queuefile_transport_init,
-    },
-  .code =		queuefile_transport_entry,
-  .tidyup =		NULL,
-  .closedown =		NULL,
-  .local =		TRUE
-  },
-#endif
-#ifdef TRANSPORT_SMTP
-  {
-  .drinfo = {
-    .driver_name =	US"smtp",
-    .options =		smtp_transport_options,
-    .options_count =	&smtp_transport_options_count,
-    .options_block =	&smtp_transport_option_defaults,
-    .options_len =	sizeof(smtp_transport_options_block),
-    .init =		smtp_transport_init,
-    },
-  .code =		smtp_transport_entry,
-  .tidyup =		NULL,
-  .closedown =		smtp_transport_closedown,
-  .local =		FALSE
-  },
-#endif
-  { .drinfo = { .driver_name = US"" }}
-};
 
 #ifndef MACRO_PREDEF
 
@@ -429,35 +306,69 @@ return g;
 gstring *
 transport_show_supported(gstring * g)
 {
-g = string_cat(g, US"Transports:");
-#ifdef TRANSPORT_APPENDFILE
-  g = string_cat(g, US" appendfile");
-  #ifdef SUPPORT_MAILDIR
-    g = string_cat(g, US"/maildir");	/* damn these subclasses */
-  #endif
-  #ifdef SUPPORT_MAILSTORE
-    g = string_cat(g, US"/mailstore");
-  #endif
-  #ifdef SUPPORT_MBX
-    g = string_cat(g, US"/mbx");
-  #endif
-#endif
-#ifdef TRANSPORT_AUTOREPLY
-  g = string_cat(g, US" autoreply");
-#endif
-#ifdef TRANSPORT_LMTP
-  g = string_cat(g, US" lmtp");
-#endif
-#ifdef TRANSPORT_PIPE
-  g = string_cat(g, US" pipe");
-#endif
-#ifdef EXPERIMENTAL_QUEUEFILE
-  g = string_cat(g, US" queuefile");
-#endif
-#ifdef TRANSPORT_SMTP
-  g = string_cat(g, US" smtp");
+uschar * b = US""		/* static-build transportnames */
+#if defined(TRANSPORT_APPENDFILE) && TRANSPORT_APPENDFILE!=2
+  " appendfile"
+# ifdef SUPPORT_MAILDIR
+    "/maildir"
+# endif
+# ifdef SUPPORT_MAILSTORE
+    "/mailstore"
+# endif
+# ifdef SUPPORT_MBX
+    "/mbx"
+# endif
+#endif
+#if defined(TRANSPORT_AUTOREPLY) && TRANSPORT_AUTOREPLY!=2
+  " autoreply"
+#endif
+#if defined(TRANSPORT_LMTP) && TRANSPORT_LMTP!=2
+  " lmtp"
+#endif
+#if defined(TRANSPORT_PIPE) && TRANSPORT_PIPE!=2
+  " pipe"
+#endif
+#if defined(EXPERIMENTAL_QUEUEFILE) && EXPERIMENTAL_QUEUEFILE!=2
+  " queuefile"
+#endif
+#if defined(TRANSPORT_SMTP) && TRANSPORT_SMTP!=2
+  " smtp"
 #endif
-return string_cat(g, US"\n");
+  ;
+
+uschar * d = US""		/* dynamic-module transportnames */
+#if defined(TRANSPORT_APPENDFILE) && TRANSPORT_APPENDFILE==2
+  " appendfile"
+# ifdef SUPPORT_MAILDIR
+    "/maildir"
+# endif
+# ifdef SUPPORT_MAILSTORE
+    "/mailstore"
+# endif
+# ifdef SUPPORT_MBX
+    "/mbx"
+# endif
+#endif
+#if defined(TRANSPORT_AUTOREPLY) && TRANSPORT_AUTOREPLY==2
+  " autoreply"
+#endif
+#if defined(TRANSPORT_LMTP) && TRANSPORT_LMTP==2
+  " lmtp"
+#endif
+#if defined(TRANSPORT_PIPE) && TRANSPORT_PIPE==2
+  " pipe"
+#endif
+#if defined(EXPERIMENTAL_QUEUEFILE) && EXPERIMENTAL_QUEUEFILE==2
+  " queuefile"
+#endif
+#if defined(TRANSPORT_SMTP) && TRANSPORT_SMTP==2
+  " smtp"
+#endif
+  ;
+
+if (*b) g = string_fmt_append(g, "Transports (built-in):%s\n", b);
+if (*d) g = string_fmt_append(g, "Transports (dynamic): %s\n", d);
+return g;
 }
 
 
diff --git a/src/src/globals.h b/src/src/globals.h
index 6bca06c00..7fc888f5b 100644
--- a/src/src/globals.h
+++ b/src/src/globals.h
@@ -1111,10 +1111,9 @@ extern int     transport_newlines;     /* Accurate count of number of newline ch
 extern const uschar **transport_filter_argv; /* For on-the-fly filtering */
 extern int     transport_filter_timeout; /* Timeout for same */
 
-extern transport_info transports_available_oldarray[]; /* Vector of available transports */
-extern transport_info * transports_available_newlist;
-extern transport_instance *transports; /* Chain of instantiated transports */
-extern transport_instance transport_defaults; /* Default values */
+extern transport_info * transports_available;	/* Listof available transports */
+extern transport_instance *transports;		/* Chain of instantiated transports */
+extern transport_instance transport_defaults;	/* Default values */
 
 extern int     transport_write_timeout;/* Set to time out individual writes */
 
diff --git a/src/src/route.c b/src/src/route.c
index 07f0a6b20..293d21c50 100644
--- a/src/src/route.c
+++ b/src/src/route.c
@@ -227,7 +227,6 @@ function. */
 void
 route_init(void)
 {
-
 int old_pool = store_pool;
 store_pool = POOL_PERM;
   {
diff --git a/src/src/routers/Makefile b/src/src/routers/Makefile
index d13a493e9..8ff3d81ab 100644
--- a/src/src/routers/Makefile
+++ b/src/src/routers/Makefile
@@ -7,7 +7,7 @@
 
 # nb: at build time, the version of this file used will have had some
 #     extra variable definitions and prepended to it and module build rules
-#     interpolated below. This is done by scripts/routers-Makefile.
+#     interpolated below. This is done by scripts/drivers-Makefile.
 
 # MAGIC-TAG-MODS-OBJ-RULES-GO-HERE
 
diff --git a/src/src/transport.c b/src/src/transport.c
index e42625ce8..063fda361 100644
--- a/src/src/transport.c
+++ b/src/src/transport.c
@@ -102,8 +102,7 @@ uschar buf[64];
 
 options_from_list(optionlist_transports, nelem(optionlist_transports), US"TRANSPORTS", NULL);
 
-//for (transport_info * ti= transports_available; ti->drinfo.driver_name[0]; ti++)
-for (driver_info * di= (driver_info *)transports_available_newlist; di; di = di->next)
+for (driver_info * di= (driver_info *)transports_available; di; di = di->next)
   {
   spf(buf, sizeof(buf), US"_DRIVER_TRANSPORT_%T", di->driver_name);
   builtin_macro_create(buf);
@@ -146,21 +145,51 @@ the work. */
 void
 transport_init(void)
 {
-for (transport_info * tblent = transports_available_oldarray;
-    *tblent->drinfo.driver_name; tblent++)
+int old_pool = store_pool;
+store_pool = POOL_PERM;
   {
-  driver_info * listent = store_get(sizeof(transport_info), tblent);
-  memcpy(listent, tblent, sizeof(transport_info));
-  listent->next = (driver_info *)transports_available_newlist;
-  transports_available_newlist = (transport_info *)listent;
+  driver_info ** anchor = (driver_info **) &transports_available;
+  extern transport_info appendfile_transport_info;
+  extern transport_info autoreply_transport_info;
+  extern transport_info lmtp_transport_info;
+  extern transport_info pipe_transport_info;
+  extern transport_info queuefile_transport_info;
+  extern transport_info smtp_transport_info;
+
+  /* Add the transport drivers that are built for static linkage to the
+  list of availables. */
+
+#if defined(TRANSPORT_APPENDFILE) && TRANSPORT_APPENDFILE!=2
+  add_driver_info(anchor, &appendfile_transport_info.drinfo, sizeof(transport_info));
+#endif
+#if defined(TRANSPORT_AUTOREPLY) && TRANSPORT_AUTOREPLY!=2
+  add_driver_info(anchor, &autoreply_transport_info.drinfo, sizeof(transport_info));
+#endif
+#if defined(TRANSPORT_LMTP) && TRANSPORT_LMTP!=2
+  add_driver_info(anchor, &lmtp_transport_info.drinfo, sizeof(transport_info));
+#endif
+#if defined(TRANSPORT_PIPE) && TRANSPORT_PIPE!=2
+  add_driver_info(anchor, &pipe_transport_info.drinfo, sizeof(transport_info));
+#endif
+#if defined(EXPERIMENTAL_QUEUEFILE) && EXPERIMENTAL_QUEUEFILE!=2
+  add_driver_info(anchor, &queuefile_transport_info.drinfo, sizeof(transport_info));
+#endif
+#if defined(TRANSPORT_SMTP) && TRANSPORT_SMTP!=2
+  add_driver_info(anchor, &smtp_transport_info.drinfo, sizeof(transport_info));
+#endif
   }
+store_pool = old_pool;
+
+/* Read the config file "transports" section, creating a transportsinstance list.
+For any yet-undiscovered driver, check for a loadable module and add it to
+those available. */
 
 readconf_driver_init((driver_instance **)&transports,     /* chain anchor */
-  (driver_info **)&transports_available_newlist,   /* available drivers */
-  sizeof(transport_info),                /* size of info block */
-  &transport_defaults,                   /* default values for generic options */
-  sizeof(transport_instance),            /* size of instance block */
-  optionlist_transports,                 /* generic options */
+  (driver_info **)&transports_available, /* available drivers */
+  sizeof(transport_info),		/* size of info block */
+  &transport_defaults,			/* default values for generic options */
+  sizeof(transport_instance),		/* size of instance block */
+  optionlist_transports,		/* generic options */
   optionlist_transports_size,
   US"transport");
 
diff --git a/src/src/transports/Makefile b/src/src/transports/Makefile
index 4eea141ec..8f759ecf0 100644
--- a/src/src/transports/Makefile
+++ b/src/src/transports/Makefile
@@ -1,8 +1,16 @@
 # Make file for building a library containing all the available transports and
 # calling it transports.a. This is called from the main make file, after cd'ing
 # to the transports subdirectory.
+#
+# Copyright (c) The Exim Maintainers 2021 - 2024
 
-OBJ = appendfile.o autoreply.o lmtp.o pipe.o queuefile.o smtp.o smtp_socks.o tf_maildir.o
+# nb: at build time, the version of this file used will have had some
+#     extra variable definitions and prepended to it and module build rules
+#     interpolated below. This is done by scripts/drivers-Makefile.
+
+# MAGIC-TAG-MODS-OBJ-RULES-GO-HERE
+
+all:		transports.a $(MODS)
 
 transports.a:    $(OBJ)
 		 @$(RM_COMMAND) -f transports.a
@@ -10,18 +18,40 @@ transports.a:    $(OBJ)
 		 @$(AR) transports.a $(OBJ)
 		 $(RANLIB) $@
 
-.SUFFIXES:       .o .c
+.SUFFIXES:       .o .c .so
 .c.o:;           @echo "$(CC) $*.c"
 		 $(FE)$(CC) -c $(CFLAGS) $(INCLUDE) $*.c
 
-appendfile.o:    $(HDRS) appendfile.c appendfile.h tf_maildir.h
-autoreply.o:     $(HDRS) autoreply.c autoreply.h
-lmtp.o:          $(HDRS) lmtp.c lmtp.h
-pipe.o:          $(HDRS) pipe.c pipe.h
-queuefile.o:     $(HDRS) queuefile.c queuefile.h
-smtp.o:          $(HDRS) smtp.c smtp.h
-smtp_socks.o:    $(HDRS) smtp_socks.c smtp.h
+.c.so:;          @echo "$(CC) -shared $*.c"
+		 $(FE)$(CC) -DDYNLOOKUP $(CFLAGS_DYNAMIC) $(CFLAGS) $(INCLUDE) $(DLFLAGS) $*.c -o $@
+
+
+$(OBJ) $(MOD): $(HDRS)
+
+autoreply.o autoreply.so:	autoreply.c autoreply.h
+lmtp.o lmtp.so:			lmtp.c lmtp.h
+pipe.o pipe.so:			pipe.c pipe.h
+queuefile.o queuefile.so:	queuefile.c queuefile.h
+
+
+# These ones depend on more than one .c source
+
+appendfile.o:	appendfile.c appendfile.h tf_maildir.c tf_maildir.h
+	@echo "$(CC) appendfile.c tf_maildir.c"
+	$(FE)$(CC) $(CFLAGS) $(INCLUDE) appendfile.c tf_maildir.c -r -o $@
+
+appendfile.so: appendfile.c appendfile.h tf_maildir.c tf_maildir.h
+	@echo "$(CC) -shared appendfile.c tf_maildir.c"
+	$(FE)$(CC) -DDYNLOOKUP $(CFLAGS_DYNAMIC) $(CFLAGS) $(INCLUDE) $(DLFLAGS) \
+		appendfile.c tf_maildir.c -o $@
+
+smtp.o:	smtp.c smtp_socks.c smtp.h
+	@echo "$(CC) smtp.c smtp_socks.c"
+	$(FE)$(CC) $(CFLAGS) $(INCLUDE) smtp.c smtp_socks.c -r -o $@
 
-tf_maildir.o:    $(HDRS) tf_maildir.c tf_maildir.h appendfile.h
+smtp.so: smtp.c smtp_socks.c smtp.h
+	@echo "$(CC) -shared smtp.c smtp_socks.c"
+	$(FE)$(CC) -DDYNLOOKUP $(CFLAGS_DYNAMIC) $(CFLAGS) $(INCLUDE) $(DLFLAGS) \
+		smtp.c smtp_socks.c -o $@
 
 # End
diff --git a/src/src/transports/appendfile.c b/src/src/transports/appendfile.c
index 14ef13c97..08a59543c 100644
--- a/src/src/transports/appendfile.c
+++ b/src/src/transports/appendfile.c
@@ -3319,6 +3319,31 @@ ret_panic:
   return FALSE;
 }
 
+
+
+
+# ifdef DYNLOOKUP
+#  define appendfile_transport_info _transport_info
+# endif
+
+transport_info appendfile_transport_info = {
+.drinfo = {
+  .driver_name =	US"appendfile",
+  .options =		appendfile_transport_options,
+  .options_count =	&appendfile_transport_options_count,
+  .options_block =	&appendfile_transport_option_defaults,	/* private options defaults */
+  .options_len =	sizeof(appendfile_transport_options_block),
+  .init =		appendfile_transport_init,
+# ifdef DYNLOOKUP
+  .dyn_magic =		TRANSPORT_MAGIC,
+# endif
+  },
+.code =		appendfile_transport_entry,
+.tidyup =	NULL,
+.closedown =	NULL,
+.local =	TRUE
+};
+
 #endif	/*!MACRO_PREDEF*/
 #endif	/*TRANSPORT_APPENDFILE*/
 /* End of transport/appendfile.c */
diff --git a/src/src/transports/autoreply.c b/src/src/transports/autoreply.c
index a6080695e..9223bc791 100644
--- a/src/src/transports/autoreply.c
+++ b/src/src/transports/autoreply.c
@@ -806,6 +806,31 @@ DEBUG(D_transport) debug_printf("%s transport succeeded\n", trname);
 return FALSE;
 }
 
+
+
+
+# ifdef DYNLOOKUP
+#  define autoreply_transport_info _transport_info
+# endif
+
+transport_info autoreply_transport_info = {
+.drinfo = {
+  .driver_name =	US"autoreply",
+  .options =		autoreply_transport_options,
+  .options_count =	&autoreply_transport_options_count,
+  .options_block =	&autoreply_transport_option_defaults,
+  .options_len =	sizeof(autoreply_transport_options_block),
+  .init =		autoreply_transport_init,
+# ifdef DYNLOOKUP
+  .dyn_magic =		TRANSPORT_MAGIC,
+# endif
+  },
+.code =		autoreply_transport_entry,
+.tidyup =	NULL,
+.closedown =	NULL,
+.local =	TRUE
+};
+
 #endif	/*!MACRO_PREDEF*/
 #endif	/*TRANSPORT_AUTOREPOL*/
 /* End of transport/autoreply.c */
diff --git a/src/src/transports/lmtp.c b/src/src/transports/lmtp.c
index ae9295292..1bff274c1 100644
--- a/src/src/transports/lmtp.c
+++ b/src/src/transports/lmtp.c
@@ -808,6 +808,31 @@ MINUS_N:
   return FALSE;
 }
 
+
+
+
+# ifdef DYNLOOKUP
+#  define lmtp_transport_info _transport_info
+# endif
+
+transport_info lmtp_transport_info = {
+.drinfo = {
+  .driver_name =	US"lmtp",
+  .options =		lmtp_transport_options,
+  .options_count =	&lmtp_transport_options_count,
+  .options_block =	&lmtp_transport_option_defaults,
+  .options_len =	sizeof(lmtp_transport_options_block),
+  .init =		lmtp_transport_init,
+# ifdef DYNLOOKUP
+  .dyn_magic =		TRANSPORT_MAGIC,
+# endif
+  },
+.code =		lmtp_transport_entry,
+.tidyup =	NULL,
+.closedown =	NULL,
+.local =	TRUE
+};
+
 #endif	/*!MACRO_PREDEF*/
 #endif	/*TRANSPORT_LMTP*/
 /* End of transport/lmtp.c */
diff --git a/src/src/transports/pipe.c b/src/src/transports/pipe.c
index 1b90c4314..b765eeae5 100644
--- a/src/src/transports/pipe.c
+++ b/src/src/transports/pipe.c
@@ -1128,6 +1128,31 @@ if (addr->transport_return != OK)
 return FALSE;
 }
 
+
+
+
+# ifdef DYNLOOKUP
+#  define pipe_transport_info _transport_info
+# endif
+
+transport_info pipe_transport_info = {
+.drinfo = {
+  .driver_name =	US"pipe",
+  .options =		pipe_transport_options,
+  .options_count =	&pipe_transport_options_count,
+  .options_block =	&pipe_transport_option_defaults,
+  .options_len =	sizeof(pipe_transport_options_block),
+  .init =		pipe_transport_init,
+# ifdef DYNLOOKUP
+  .dyn_magic =		TRANSPORT_MAGIC,
+# endif
+  },
+.code =		pipe_transport_entry,
+.tidyup =	NULL,
+.closedown =	NULL,
+.local =	TRUE
+};
+
 #endif	/*!MACRO_PREDEF*/
 #endif	/*TRASPORT_PIPE*/
 /* End of transport/pipe.c */
diff --git a/src/src/transports/queuefile.c b/src/src/transports/queuefile.c
index 2c35b3145..64031e55d 100644
--- a/src/src/transports/queuefile.c
+++ b/src/src/transports/queuefile.c
@@ -285,5 +285,30 @@ put in the first address of a batch. */
 return FALSE;
 }
 
+
+
+
+# ifdef DYNLOOKUP
+#  define queuefile_transport_info _transport_info
+# endif
+
+transport_info queuefile_transport_info = {
+.drinfo = {
+  .driver_name =	US"queuefile",
+  .options =		queuefile_transport_options,
+  .options_count =	&queuefile_transport_options_count,
+  .options_block =	&queuefile_transport_option_defaults,
+  .options_len =	sizeof(queuefile_transport_options_block),
+  .init =		queuefile_transport_init,
+# ifdef DYNLOOKUP
+  .dyn_magic =		TRANSPORT_MAGIC,
+# endif
+  },
+.code =		queuefile_transport_entry,
+.tidyup =	NULL,
+.closedown =	NULL,
+.local =	TRUE
+};
+
 #endif /*!MACRO_PREDEF*/
 #endif /*EXPERIMENTAL_QUEUEFILE*/
diff --git a/src/src/transports/smtp.c b/src/src/transports/smtp.c
index 25858d982..d25a2b1f6 100644
--- a/src/src/transports/smtp.c
+++ b/src/src/transports/smtp.c
@@ -6230,6 +6230,31 @@ DEBUG(D_transport) debug_printf("Leaving %s transport\n", trname);
 return TRUE;   /* Each address has its status */
 }
 
+
+
+
+# ifdef DYNLOOKUP
+#  define smtp_transport_info _transport_info
+# endif
+
+transport_info smtp_transport_info = {
+.drinfo = {
+  .driver_name =	US"smtp",
+  .options =		smtp_transport_options,
+  .options_count =	&smtp_transport_options_count,
+  .options_block =	&smtp_transport_option_defaults,
+  .options_len =	sizeof(smtp_transport_options_block),
+  .init =		smtp_transport_init,
+# ifdef DYNLOOKUP
+  .dyn_magic =		TRANSPORT_MAGIC,
+# endif
+  },
+.code =		smtp_transport_entry,
+.tidyup =	NULL,
+.closedown =	smtp_transport_closedown,
+.local =	FALSE
+};
+
 #endif	/*!MACRO_PREDEF*/
 /* vi: aw ai sw=2
 */
diff --git a/test/confs/0000 b/test/confs/0000
index 795701bd7..5db8ac8cf 100644
--- a/test/confs/0000
+++ b/test/confs/0000
@@ -11,5 +11,6 @@ tls_advertise_hosts =
 keep_environment =
 
 begin routers
+begin transports
 
 # End
diff --git a/test/runtest b/test/runtest
index 292233551..632672324 100755
--- a/test/runtest
+++ b/test/runtest
@@ -1164,7 +1164,7 @@ RESET_AFTER_EXTRA_LINE_READ:
 		  | Lookups(?:\(built-in\))?:
 		  | Support\ for:
 		  | Routers\ \((?:built-in|dynamic)\):
-		  | Transports:
+		  | Transports\ \((?:built-in|dynamic)\):
 		  | Malware:
 		  | log\ selectors\ =
 		  | cwd=
@@ -3754,7 +3754,7 @@ while (<EXIMINFO>)
     print;
     @temp = split /(\s+)/, $1;
     push(@temp, ' ');
-    my %temp_routers= @temp;
+    my %temp_routers = @temp;
     @parm_routers{keys %temp_routers} = values %temp_routers;
     }
 
@@ -3762,13 +3762,15 @@ while (<EXIMINFO>)
   # that the basic transport name is set, and then the name with each of the
   # options.
 
-  elsif (/^Transports: (.*)/)
+  elsif (/^Transports \((?:built-in|dynamic)\): (.*)/)
     {
     print;
     @temp = split /(\s+)/, $1;
     my($i,$k);
     push(@temp, ' ');
-    %parm_transports = @temp;
+    my %temp_transports = @temp;
+    @parm_transports{keys %temp_transports} = values %temp_transports;
+
     foreach $k (keys %parm_transports)
       {
       if ($k =~ "/")
-- 
2.30.2