Final set of changes for making redundant xlat function registration …

…not suck

We now group module xlats by name (all self-named module expansions are considered equal).

This allows:

redundant {
    sql
    linelog
}

Which would issue a query against SQL, and then log it to disk.

The instantiate code catches/disallows calls to incompatible module expansions in much the same way as C's _Generic does...

doc/antora/modules/reference/pages/unlang/load-balance.adoc

@@ -46,13 +46,13 @@ places.  Instead of copying the same text multiple times, a
 directory.
 
 For example, the following text can be placed into the file
-`mods-enabled/sql123`.  Once it is there, it can be used as a module
-named `sql123`, and used anywhere a module is allowed to use.
+`mods-enabled/sql_all`.  Once it is there, it can be used as a module
+named `sql_all`, and used anywhere a module is allowed to use.
 
 .Example of Load-Balance SQL module
 [source,unlang]
 ----
-load-balance sql123 {
+load-balance sql_all {
     sql1
     sql2
     sql3
@@ -61,18 +61,18 @@ load-balance sql123 {
 
 In previous versions of the server, this definition would be placed
 into the `instantiate` section of `radiusd.conf.  This configuration
-is no longer used, and the `sql123` definition can just be placed as
+is no longer used, and the `sql_all` definition can just be placed as
 a module definition into the `mods-enabled/` directory.
 
 == Load-Balance Expansions
 
-When the `sql123` module is defined as above, it can also be used as
+When the `sql_all` module is defined as above, it can also be used as
 in a xref:xlat/index.adoc[dynamic expansion]:
 
 .Example of Load-Balance SQL module
 [source,unlang]
 ----
-&Reply-Message := %sql123("SELECT message FROM table WHERE name='%{User-Name}'")
+&Reply-Message := %sql_all("SELECT message FROM table WHERE name='%{User-Name}'")
 }
 ----
 

doc/antora/modules/reference/pages/unlang/redundant-load-balance.adoc

@@ -53,13 +53,13 @@ places.  Instead of copying the same text multiple times, a
 directory.
 
 For example, the following text can be placed into the file
-`mods-enabled/sql123`.  Once it is there, it can be used as a module
-named `sql123`, and used anywhere a module is allowed to use.
+`mods-enabled/sql_all`.  Once it is there, it can be used as a module
+named `sql_all`, and used anywhere a module is allowed to use.
 
 .Example of Redundant-Load-Balance SQL module
 [source,unlang]
 ----
-redundant-load-balance sql123 {
+redundant-load-balance sql_all {
     sql1
     sql2
     sql3
@@ -68,18 +68,18 @@ redundant-load-balance sql123 {
 
 In previous versions of the server, this definition would be placed
 into the `instantiate` section of `radiusd.conf.  This configuration
-is no longer used, and the `sql123` definition can just be placed as
+is no longer used, and the `sql_all` definition can just be placed as
 a module definition into the `mods-enabled/` directory.
 
 == Redundant-Load-Balance Expansions
 
-When the `sql123` module is defined as above, it can also be used as
+When the `sql_all` module is defined as above, it can also be used as
 in a xref:xlat/index.adoc[dynamic expansion]:
 
 .Example of Redundant-Load-Balance SQL module
 [source,unlang]
 ----
-&Reply-Message := %sql123("SELECT message FROM table WHERE name='%{User-Name}'")
+&Reply-Message := %sql_all("SELECT message FROM table WHERE name='%{User-Name}'")
 }
 ----
 

doc/antora/modules/reference/pages/unlang/redundant.adoc

@@ -46,13 +46,13 @@ places.  Instead of copying the same text multiple times, a
 directory.
 
 For example, the following text can be placed into the file
-`mods-enabled/sql123`.  Once it is there, it can be used as a module
-named `sql123`, and used anywhere a module is allowed to use.
+`mods-enabled/sql_all`.  Once it is there, it can be used as a module
+named `sql_all`, and used anywhere a module is allowed to use.
 
 .Example of Redundant SQL module
 [source,unlang]
 ----
-redundant sql123 {
+redundant sql_all {
     sql1
     sql2
     sql3
@@ -61,30 +61,101 @@ redundant sql123 {
 
 In previous versions of the server, this definition would be placed
 into the `instantiate` section of `radiusd.conf.  This configuration
-is no longer used, and the `sql123` definition can just be placed as
+is no longer used, and the `sql_all` definition can just be placed as
 a module definition into the `mods-enabled/` directory.
 
 == Redundant Expansions
 
-When the `sql123` module is defined as above, it can also be used as
-in a xref:xlat/index.adoc[dynamic expansion]:
+Modules may be used in a `redundant` section, and modules can register
+xref:xlat/index.adoc[dynamic expansions].  It is therefore also useful
+to define redundant dynamic expansions.  The good news is that the
+server does this automatically.
 
-.Example of Redundant SQL module
+When a `redundant` section is defined, _and_ where all of the modules
+in the `redundant` section reference the same underlying module
+(e.g. `sql`, or `ldap`), the server then automatically registers a new
+_redundant expansion_, with the name of the `redundant` section.  The
+example below shows how this works.
+
+.Example
 [source,unlang]
 ----
-&Reply-Message := %sql123("SELECT message FROM table WHERE name='%{User-Name}'")
+redundant sql_all {
+	sql1
+	sql2
+	sql3
 }
 ----
 
-The expansion works exactly like a `redundant` block.  First `sql1` is
-tried.  If that fails, `sql2` is tried.  Then if that fails, `sql3` is
-tried.
+Each `sql` module will register it's own xref:xlat/index.adoc[dynamic
+expansions], such as `%sql1(...)`, and `%sql2(...)` and `%sql3(...).
+However, there will _also_ be a new SQL expansion defined:
+
+----
+%sql_all(...)
+----
+
+This is a _redundant_ expansion.  When it is called, it follows
+operation of the `redundant` block which defined it.  That is, it will
+first run `%sql1(...)`, then if that fails, run `%sql2(...)`, etc.
+
+.Example of Redundant SQL module
+[source,unlang]
+----
+&Reply-Message := %sql_all("SELECT message FROM table WHERE name='%{User-Name}'")
+----
 
 The one caveat here is that the arguments passed to the underlying
 modules are expanded again _for each call_.  If the expansion
 arguments have side effects, then those side effects can be applied
 multiple times, once for each `redundant` attempt.
 
+=== Additional redundant expansions
+
+Modules can register multiple expansions. If the module's expansion
+shares the module's instance name, the redundant expansion is
+registered with the `redundant` section name. Otherwise, the redundant
+expansion is _qualified_ with the `redundant` section name.
+
+For example, the `sql` module provides two expansions, a self-named
+expansion and a `group` expansion.  Using the example from the previous
+section, `redundant sql_all {...}` would register the following:
+
+----
+%sql_all(...)
+%sql_all.group(...)
+----
+
+=== Module expansion grouping
+
+Module expansions which share the same name are grouped into the same
+redundant expansion.  This may result in only a subset of the module
+expansions in a `redundant` section being called by a redundant
+expansion.
+
+.Example
+[source,unlang]
+----
+redundant sql_and_ldap {
+	sql1
+	sql2
+	ldap1
+    ldap2
+}
+----
+
+The `sql_and_ldap` redundant section would register the following
+expansions:
+
+- `%sql_and_ldap(...)` which would call `%sql1(...)`, `%sql2(...)`, `%ldap1(...)`, and `%ldap2(...)`
+- `%sql_and_ldap.group(...)` which would call `%sql1(...)`, `%sql2(...)`
+- `%sql_and_ldap.memberof(...)` which would call `%ldap1(...)`, `%ldap2(...)`
+- `%sql_and_ldap.profile(...)` which would call `%ldap1(...)`, `%ldap2(...)`
+
+If the arguments passed to the redundant expansion are not compatible
+with _all_ the module expansions it would call, the server will log an
+error and either fail to start, or stop processing the expression which
+called the redundant expansion.
 
 // Copyright (C) 2021 Network RADIUS SAS.  Licenced under CC-by-NC 4.0.
 // This documentation was developed by Network RADIUS SAS.

src/lib/server/module_rlm.c

@@ -285,7 +285,7 @@ xlat_t *module_rlm_xlat_register(TALLOC_CTX *ctx, module_inst_ctx_t const *mctx,
 	mrx->xlat = x;
 	mrx->mi = mi;
 
-	fr_rb_insert(&mri->xlats, mrx);
+	fr_dlist_insert_tail(&mri->xlats, mrx);
 
 	return x;
 }
@@ -1100,16 +1100,6 @@ static int module_method_validate(module_instance_t *mi)
 	return module_method_group_validate(&mrlm->method);
 }
 
-/** Compare xlat functions registered to a module
- */
-static int8_t module_rlm_xlat_cmp(void const *one, void const *two)
-{
-	module_rlm_xlat_t const *a = one;
-	module_rlm_xlat_t const *b = two;
-
-	return xlat_func_cmp(a->xlat, b->xlat);
-}
-
 /** Allocate a rlm module instance
  *
  * These have extra space allocated to hold the dlist of associated xlats.
@@ -1138,7 +1128,8 @@ module_instance_t *module_rlm_instance_alloc(module_list_t *ml,
 
 	MEM(mri = talloc(mi, module_rlm_instance_t));
 	module_instance_uctx_set(mi, mri);
-	fr_rb_inline_init(&mri->xlats, module_rlm_xlat_t, node, module_rlm_xlat_cmp, NULL);
+
+	fr_dlist_talloc_init(&mri->xlats, module_rlm_xlat_t, entry);
 
 	return mi;
 }

src/lib/server/module_rlm.h

@@ -41,7 +41,7 @@ struct module_rlm_s {
 };
 
 struct module_rlm_instance_s {
-	fr_rb_tree_t			xlats;			//!< xlats registered to this module instance.
+	fr_dlist_head_t			xlats;			//!< xlats registered to this module instance.
 								///< This is used by the redundant/loadbalance
 								///< xlats to register versions of the xlats
 								///< exported by the module instances.
@@ -51,8 +51,8 @@ struct module_rlm_instance_s {
  */
 typedef struct {
 	xlat_t const			*xlat;			//!< The xlat function.
-	module_instance_t const		*mi;			//!< The module instance that registered the xlat.
-	fr_rb_node_t			node;			//!< Entry in an rbtree of registered xlats.
+	module_instance_t		*mi;			//!< The module instance that registered the xlat.
+	fr_dlist_t			entry;			//!< Entry in a linked list of registered xlats.
 } module_rlm_xlat_t;
 
 /** The output of module_rlm_by_name_and_method