[exim-cvs] Macros for module func call numbers

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Author: Exim Git Commits Mailing List
Date:  
To: exim-cvs
Subject: [exim-cvs] Macros for module func call numbers
Gitweb: https://git.exim.org/exim.git/commitdiff/4d12daceb37ee7d0636f3bed0c8709a2bbdee653
Commit:     4d12daceb37ee7d0636f3bed0c8709a2bbdee653
Parent:     8b65d4dd61751329a50cddcee9d4a082700d4ed2
Author:     Jeremy Harris <jgh146exb@???>
AuthorDate: Sat Aug 31 22:07:17 2024 +0100
Committer:  Jeremy Harris <jgh146exb@???>
CommitDate: Sun Sep 1 01:28:00 2024 +0100


    Macros for module func call numbers
---
 src/OS/Makefile-Base         |  4 +++
 src/scripts/MakeLinks        |  2 +-
 src/src/acl.c                | 17 ++++-----
 src/src/exim.h               |  2 ++
 src/src/expand.c             |  4 +--
 src/src/lookups/spf.c        |  7 ++--
 src/src/miscmods/README      | 84 ++++++++++++++++++++++++++++++++++++++++++++
 src/src/miscmods/dmarc.c     | 11 +++---
 src/src/miscmods/dmarc_api.h | 17 +++++++++
 src/src/miscmods/spf.c       | 12 +++----
 src/src/miscmods/spf_api.h   | 19 ++++++++++
 src/src/receive.c            |  2 +-
 12 files changed, 153 insertions(+), 28 deletions(-)


diff --git a/src/OS/Makefile-Base b/src/OS/Makefile-Base
index 43cec361c..591b4261c 100644
--- a/src/OS/Makefile-Base
+++ b/src/OS/Makefile-Base
@@ -685,6 +685,8 @@ HDRS  =    blob.h \
     hintsdb/hints_tdb.h \
     local_scan.h \
     macros.h \
+    miscmods/dmarc_api.h \
+    miscmods/spf_api.h \
     mytypes.h \
     path_max.h \
     sha_ver.h \
@@ -704,6 +706,8 @@ PHDRS = ../config.h \
     ../hintsdb/hints_tdb.h \
     ../local_scan.h \
     ../macros.h \
+    ../miscmods/dmarc_api.h \
+    ../miscmods/spf_api.h \
     ../mytypes.h \
     ../path_max.h \
     ../structs.h \
diff --git a/src/scripts/MakeLinks b/src/scripts/MakeLinks
index e45097243..0be066352 100755
--- a/src/scripts/MakeLinks
+++ b/src/scripts/MakeLinks
@@ -94,7 +94,7 @@ d="miscmods"
 mkdir $d
 cd $d
 # Makefile is generated
-for f in dmarc.c dmarc.h spf.c spf.h
+for f in dmarc.c dmarc.h dmarc_api.h spf.c spf.h spf_api.h
 do
   ln -s ../../src/$d/$f $f
 done
diff --git a/src/src/acl.c b/src/src/acl.c
index 30fc09174..023ac2ff6 100644
--- a/src/src/acl.c
+++ b/src/src/acl.c
@@ -3961,29 +3961,24 @@ for (; cb; cb = cb->next)
       typedef uschar * (*efn_t)(int);
       uschar * expanded_query;


-debug_printf("%s %d\n", __FUNCTION__, __LINE__);
       if (!mi)
     { rc = DEFER; break; }            /* shouldn't happen */


-debug_printf("%s %d: mi %p\n", __FUNCTION__, __LINE__, mi);
       if (!f.dmarc_has_been_checked)
     {
     typedef int (*pfn_t)(void);
-    (void) (((pfn_t *) mi->functions)[0]) ();    /* dmarc_process */
+    (void) (((pfn_t *) mi->functions)[DMARC_PROCESS]) ();
     f.dmarc_has_been_checked = TRUE;
     }


-debug_printf("%s %d\n", __FUNCTION__, __LINE__);
       /* used long way of dmarc_exim_expand_query() in case we need more
       view into the process in the future. */


       /*XXX is this call used with any other arg? */
-      expanded_query = (((efn_t *) mi->functions)[1]) (DMARC_VERIFY_STATUS);
-
-debug_printf("%s %d\n", __FUNCTION__, __LINE__);
+      expanded_query = (((efn_t *) mi->functions)[DMARC_EXPAND_QUERY])
+                              (DMARC_VERIFY_STATUS);
       rc = match_isinlist(expanded_query,
               &arg, 0, NULL, NULL, MCL_STRING, TRUE, NULL);
-debug_printf("%s %d\n", __FUNCTION__, __LINE__);
       }
       break;
 #endif
@@ -4223,7 +4218,9 @@ debug_printf("%s %d\n", __FUNCTION__, __LINE__);
       /* We have hardwired function-call numbers, and also prototypes for the
       functions.  We could do a function name table search for the number
       but I can't see how to deal with prototypes.  Is a K&R non-prototyped
-      function still usable with today's compilers? */
+      function still usable with today's compilers (but we would lose on
+      type-checking)?  We could macroize the typedef, and even the function
+      table access - but it obscures how it works rather. */
       {
       misc_module_info * mi = misc_mod_find(US"spf", &log_message);
       typedef int (*fn_t)(const uschar **, const uschar *, int);
@@ -4232,7 +4229,7 @@ debug_printf("%s %d\n", __FUNCTION__, __LINE__);
       if (!mi)
     { rc = DEFER; break; }            /* shouldn't happen */


-      fn = ((fn_t *) mi->functions)[0];        /* spf_process() */
+      fn = ((fn_t *) mi->functions)[SPF_PROCESS];


       rc = fn(&arg, sender_address,
           cb->type == ACLC_SPF ? SPF_PROCESS_NORMAL : SPF_PROCESS_GUESS);
diff --git a/src/src/exim.h b/src/src/exim.h
index 284748c5d..c996a2f8c 100644
--- a/src/src/exim.h
+++ b/src/src/exim.h
@@ -544,12 +544,14 @@ config.h, mytypes.h, and store.h, so we don't need to mention them explicitly.
 #endif
 #ifdef SUPPORT_SPF
 # include "miscmods/spf.h"
+# include "miscmods/spf_api.h"
 #endif
 #ifndef DISABLE_DKIM
 # include "dkim.h"
 #endif
 #ifdef SUPPORT_DMARC
 # include "miscmods/dmarc.h"
+# include "miscmods/dmarc_api.h"
 # include <opendmarc/dmarc.h>
 #endif


diff --git a/src/src/expand.c b/src/src/expand.c
index a6b05bd87..af3816051 100644
--- a/src/src/expand.c
+++ b/src/src/expand.c
@@ -4888,7 +4888,7 @@ while (*s)
     if (mi)
       {
       typedef gstring * (*fn_t)(gstring *);
-      fn_t fn = ((fn_t *) mi->functions)[1];    /* authres_spf */
+      fn_t fn = ((fn_t *) mi->functions)[SPF_AUTHRES];
       yield = fn(yield);
       }
     }
@@ -4903,7 +4903,7 @@ while (*s)
       {
       /*XXX is authres common enough to be generic? */
       typedef gstring * (*fn_t)(gstring *);
-      fn_t fn = ((fn_t *) mi->functions)[2];    /* authres_dmarc*/
+      fn_t fn = ((fn_t *) mi->functions)[DMARC_AUTHRES];
       yield = fn(yield);
       }
     }
diff --git a/src/src/lookups/spf.c b/src/src/lookups/spf.c
index a06f9117d..996bae294 100644
--- a/src/src/lookups/spf.c
+++ b/src/src/lookups/spf.c
@@ -39,7 +39,7 @@ misc_module_info * mi = misc_mod_find(US"spf", errmsg);
 if (mi)
   {
   typedef void * (*fn_t)(const uschar *, uschar **);
-  return (((fn_t *) mi->functions)[3]) (filename, errmsg);
+  return (((fn_t *) mi->functions)[SPF_OPEN]) (filename, errmsg);
   }
 return NULL;
 }
@@ -52,7 +52,7 @@ misc_module_info * mi = misc_mod_find(US"spf", NULL);
 if (mi)
   {
   typedef void (*fn_t)(void *);
-  return (((fn_t *) mi->functions)[4]) (handle);
+  return (((fn_t *) mi->functions)[SPF_CLOSE]) (handle);
   }
 }


@@ -67,7 +67,8 @@ if (mi)
   {
   typedef int (*fn_t) (void *, const uschar *, const uschar *,
               int, uschar **, uschar **, uint *, const uschar *);
-  return (((fn_t *) mi->functions)[5]) (handle, filename, keystring, key_len,
+  return (((fn_t *) mi->functions)[SPF_FIND])
+                      (handle, filename, keystring, key_len,
                       result, errmsg, do_cache, opts);
   }
 return FAIL;
diff --git a/src/src/miscmods/README b/src/src/miscmods/README
new file mode 100644
index 000000000..e534a4eed
--- /dev/null
+++ b/src/src/miscmods/README
@@ -0,0 +1,84 @@
+/*************************************************
+*     Exim - an Internet mail transport agent    *
+*************************************************/
+
+Copyright (c) The Exim Maintainers 2024
+
+This directory contains source for modules that can be built as part
+of Exim, either static-linked or as dynamic-load modules. Doing the
+latter keeps the runtime binary smaller when a feature is not used
+by the configuration, especially when a library is involved.
+
+Which modules are built, and the choice of static vs. dynamic, is
+under the control of the Local/Makefile at build time.
+Any combination of static/dynamic is valid.
+
+Moudules built for dynamic load must be installed in a directory
+which is defined in Local/Makefile.
+
+The API starts with a struct with a known name <foo>_module_info.
+For dynamic builds this includes a magic number permitting versioning
+of the highlevel interface.
+The structure has elements for some commonly-needed call types
+(init, version-report etc.).  Any my be left as null pointers;
+those present will be called at appropriate times.
+
+The current list is
+    init
+    lib_vers_report
+    smtp_reset
+    msg_init
+
+Then there are three pair of elements, each being a table pointer
+and table length, for options, functions, and variable that the
+module provides.
+
+The options table defines main-section configuration options, using
+the same definition entry struct as the main table in readconf.c;
+entries here should have their proper opt_<type> and
+should be duplicated in the main table, but with opt_module and the
+module name (this supports both getting the module loaded, if dynamic,
+and writing the value from the config). Entries must be in order by
+the option name.
+
+The functions table defines service functions additional to the "common"
+ones noted above.  Each offset in the table should have a #define in an
+include-file brought in to the general set by exim.h.
+
+The variables table defins $variables for expansion, using the same
+definition entry struct as the main var_table in expand.c;
+entries here should have their proper vtype_<type> and should be duplicated
+in the main table but with vtype_module and the module name.
+
+There are service functions to locate and to locate-or-load modules
+by name; these hide the static/dynamic aspect of a module.  Most
+new coding will only need these for calls to the "additiona" custom
+functions a module provides. The example code is:
+
+      {
+      /* You need to know the function's prototype */
+      typedef int (*fn_t)(const uschar **, const uschar *, int);
+      fn_t fn;
+      misc_module_info * mi = misc_mod_find(US"spf", &log_message);
+
+      if (mi)
+    {
+    fn = ((fn_t *) mi->functions)[SPF_PROCESS];
+    rc = fn(args...);
+    }
+      }
+
+
+
+Adding new modules
+------------------
+
+Put the code in this directory.  Use filenames starting with the module name.
+Write an include file with anything callers need to know, in particular
+#defines for the function call numbers.  Include that file from exim.h
+and add it to HDRS and PHDRS in OS/Makefile-Base.
+Add a SUPPORT_<foo> line to Local/Makefile, and (if dynamic) any
+SUPPORT_<foo>_INCLUDE or SUPPORT_<foo>_LIBS required.
+Add the capitalised module name <foo> to the "miscmods" like in
+scripts/Configure-Makefile.
+Add all the filenames to the "miscmods" list in scripts/Makelinks
diff --git a/src/src/miscmods/dmarc.c b/src/src/miscmods/dmarc.c
index 0a97bf6b7..37648d045 100644
--- a/src/src/miscmods/dmarc.c
+++ b/src/src/miscmods/dmarc.c
@@ -461,7 +461,8 @@ if (!dmarc_abort && !sender_host_authenticated)
     {
     typedef SPF_response_t * (*fn_t)(void);
     if (spf_mod_info)
-      spf_response_p = ((fn_t *) spf_mod_info->functions)[2]();    /* spf_get_response */
+      /*XXX ugly use of a pointer */
+      spf_response_p = ((fn_t *) spf_mod_info->functions)[SPF_GET_RESPONSE]();
     }


if (!spf_response_p)
@@ -746,10 +747,10 @@ static optionlist dmarc_options[] = {
};

 static void * dmarc_functions[] = {
-  dmarc_process,
-  dmarc_exim_expand_query,
-  authres_dmarc,
-  dmarc_store_data,
+  [DMARC_PROCESS] =    dmarc_process,
+  [DMARC_EXPAND_QUERY] = dmarc_exim_expand_query,
+  [DMARC_AUTHRES] =    authres_dmarc,
+  [DMARC_STORE_DATA] =    dmarc_store_data,
 };


 /* dmarc_forensic_sender is provided for visibility of the the option setting
diff --git a/src/src/miscmods/dmarc_api.h b/src/src/miscmods/dmarc_api.h
new file mode 100644
index 000000000..6ba8a5060
--- /dev/null
+++ b/src/src/miscmods/dmarc_api.h
@@ -0,0 +1,17 @@
+/*************************************************
+*     Exim - an Internet mail transport agent    *
+*************************************************/
+
+/* Copyright (c) The Exim Maintainers 2024 */
+/* See the file NOTICE for conditions of use and distribution. */
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+/* API definitions for the dmarc module */
+
+
+/* Function table entry numbers */
+
+#define    DMARC_PROCESS        0
+#define DMARC_EXPAND_QUERY    1
+#define DMARC_AUTHRES        2
+#define DMARC_STORE_DATA    3
diff --git a/src/src/miscmods/spf.c b/src/src/miscmods/spf.c
index f28fd0cbf..ea23c1c65 100644
--- a/src/src/miscmods/spf.c
+++ b/src/src/miscmods/spf.c
@@ -565,13 +565,13 @@ static optionlist spf_options[] = {
 };


 static void * spf_functions[] = {
-  spf_process,
-  authres_spf,
-  spf_get_response,        /* ugly; for dmarc */
+  [SPF_PROCESS] =    spf_process,
+  [SPF_AUTHRES] =    authres_spf,
+  [SPF_GET_RESPONSE] =    spf_get_response,        /* ugly; for dmarc */


-  spf_lookup_open,
-  spf_lookup_close,
-  spf_lookup_find,
+  [SPF_OPEN] =        spf_lookup_open,
+  [SPF_CLOSE] =        spf_lookup_close,
+  [SPF_FIND] =        spf_lookup_find,
 };


 static var_entry spf_variables[] = {
diff --git a/src/src/miscmods/spf_api.h b/src/src/miscmods/spf_api.h
new file mode 100644
index 000000000..3801e3e3f
--- /dev/null
+++ b/src/src/miscmods/spf_api.h
@@ -0,0 +1,19 @@
+/*************************************************
+*     Exim - an Internet mail transport agent    *
+*************************************************/
+
+/* Copyright (c) The Exim Maintainers 2024 */
+/* See the file NOTICE for conditions of use and distribution. */
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+/* API definitions for the spfmodule */
+
+
+/* Function table entry numbers */
+
+#define    SPF_PROCESS        0
+#define SPF_AUTHRES        1
+#define SPF_GET_RESPONSE    2
+#define SPF_OPEN        3
+#define SPF_CLOSE        4
+#define SPF_FIND        5
diff --git a/src/src/receive.c b/src/src/receive.c
index 37b152f48..a6b7722bf 100644
--- a/src/src/receive.c
+++ b/src/src/receive.c
@@ -3631,7 +3631,7 @@ else
     if (mi)
       {
       typedef int (*fn_t)(header_line *);
-      (((fn_t *) mi->functions)[3]) (dmarc_from_header);
+      (((fn_t *) mi->functions)[DMARC_STORE_DATA]) (dmarc_from_header);
       }
     }
 #endif


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