cached_fs_rom: do not change dir for "/nix/store/…" ROMs

nixos-modules/store-wrapper.dhall

@@ -12,44 +12,6 @@ let TextMapType = Prelude.Map.Type Text
 
 let Manifest/Type = TextMapType (TextMapType Text)
 
-let storeServiceRoute =
-      { service =
-        { name = "ROM", label = Init.LabelSelector.prefix "/nix/store/" }
-      , route =
-          Init.Route.Type.Parent
-            { prefix = Some "", suffix = None Text, diag = Some True }
-      }
-
-let withStoreRoute =
-      λ(attrs : Child.Attributes.Type) →
-        attrs
-        with routes = attrs.routes # [ storeServiceRoute ]
-
-let Child/withStoreRoutes
-    : Child.Type → Child.Type
-    = λ(child : Child.Type) →
-        child
-          Child.Type
-          { flat =
-              λ(attrs : Child.Attributes.Type) →
-                Child.flat (withStoreRoute attrs)
-          , nested =
-              λ(children : Prelude.Map.Type Text Child.Type) →
-              λ(attrs : Child.Attributes.Type) →
-                Child.nested children (withStoreRoute attrs)
-          }
-
-let Init/withStoreRoutes =
-      λ(init : Init.Type) →
-        init
-        with children =
-            Prelude.Map.map
-              Text
-              Child.Type
-              Child.Type
-              Child/withStoreRoutes
-              init.children
-
 in  λ(subinit : Init.Type) →
     λ(storeName : Text) →
     λ(storeSize : Natural) →
@@ -168,7 +130,7 @@ in  λ(subinit : Init.Type) →
                 , child
                     "nixos"
                     ( Init.toChild
-                        (Init/withStoreRoutes subinit)
+                        subinit
                         Init.Attributes::{
                         , exitPropagate = True
                         , resources = Init.Resources::{

packages/genodelabs/cached_fs_rom.patch

@@ -1,7 +1,7 @@
-From 3ff27b172afd3ee436f9cce754c15d5913f0cb86 Mon Sep 17 00:00:00 2001
+From e65583c3e9cf0e9c326bb2d414d40fa32f64f9c6 Mon Sep 17 00:00:00 2001
 From: Emery Hemingway <ehmry@posteo.net>
 Date: Tue, 3 Nov 2020 15:28:56 +0100
-Subject: [PATCH 1/2] cached_fs_rom: resolve symlinks
+Subject: [PATCH 1/3] cached_fs_rom: resolve symlinks
 
 Follow symlinks from ROM requests to files. This complicates the
 implementation but allows ROM requests to be redirected at both the
@@ -9,11 +9,11 @@ label routing and the file-system layers. Redirecting ROMs with symlinks
 is useful for retrieving ROMs from deeply nested or otherwise
 excessively long file-system paths.
 ---
- repos/os/src/server/cached_fs_rom/main.cc | 469 +++++++++++++---------
+ repos/os/src/server/cached_fs_rom/main.cc | 472 +++++++++++++---------
- 1 file changed, 278 insertions(+), 191 deletions(-)
+ 1 file changed, 281 insertions(+), 191 deletions(-)
 
 diff --git a/repos/os/src/server/cached_fs_rom/main.cc b/repos/os/src/server/cached_fs_rom/main.cc
-index 9e4e4d0eee..5f2aea63f5 100755
+index 9e4e4d0eee..bac2c075a9 100755
 --- a/repos/os/src/server/cached_fs_rom/main.cc
 +++ b/repos/os/src/server/cached_fs_rom/main.cc
 @@ -5,7 +5,7 @@
@@ -534,7 +534,7 @@ index 9e4e4d0eee..5f2aea63f5 100755
  		catch (Permission_denied) { error(file_path, ": permission denied"); }
  		catch (...)               { error(file_path, ": unhandled error");   }
  		throw Service_denied();
-@@ -364,55 +444,55 @@ struct Cached_fs_rom::Main final : Genode::Session_request_handler
+@@ -364,55 +444,58 @@ struct Cached_fs_rom::Main final : Genode::Session_request_handler
  		 ** Find ROM in cache **
  		 ***********************/
  
@@ -592,6 +592,9 @@ index 9e4e4d0eee..5f2aea63f5 100755
 +
 +		if (pending) /* wait until transfer completes */
 +			return;
++
++		if (diag)
++			log("lookup \"", path, "\" for \"", label, "\"");
  
 +		/* initiate new transfer or throw Service_denied */
 +		try_transfer(path, [&] () {
@@ -619,7 +622,7 @@ index 9e4e4d0eee..5f2aea63f5 100755
  	void handle_session_close(Parent::Server::Id pid) override
  	{
  		Session_space::Id id { pid.value };
-@@ -425,6 +505,9 @@ struct Cached_fs_rom::Main final : Genode::Session_request_handler
+@@ -425,6 +508,9 @@ struct Cached_fs_rom::Main final : Genode::Session_request_handler
  		});
  	}
  
@@ -629,7 +632,7 @@ index 9e4e4d0eee..5f2aea63f5 100755
  	void handle_packets()
  	{
  		Tx_source &source = *fs.tx();
-@@ -439,12 +522,16 @@ struct Cached_fs_rom::Main final : Genode::Session_request_handler
+@@ -439,12 +525,16 @@ struct Cached_fs_rom::Main final : Genode::Session_request_handler
  			transfers.apply<Transfer&>(
  				Transfer_space::Id{pkt.handle().value}, [&] (Transfer &transfer)
  			{
@@ -654,10 +657,10 @@ index 9e4e4d0eee..5f2aea63f5 100755
 2.28.0
 
 
-From 4bff3638684e807a79a24e81bf59913849c9c100 Mon Sep 17 00:00:00 2001
+From 8e994fdb882071d224b1bb2b6efc711571b523f0 Mon Sep 17 00:00:00 2001
 From: Emery Hemingway <ehmry@posteo.net>
 Date: Tue, 3 Nov 2020 17:37:50 +0100
-Subject: [PATCH 2/2] cached_fs_rom: add directory session policy
+Subject: [PATCH 2/3] cached_fs_rom: add directory session policy
 
 Support for directing ROM requests into directories by policy.
 ---
@@ -686,7 +689,7 @@ index 0000000000..855c20ba7c
 +!   <default-policy directory="rom/bin" />
 +! </config>
 diff --git a/repos/os/src/server/cached_fs_rom/main.cc b/repos/os/src/server/cached_fs_rom/main.cc
-index 5f2aea63f5..59dc2c7d98 100755
+index bac2c075a9..8df3001111 100755
 --- a/repos/os/src/server/cached_fs_rom/main.cc
 +++ b/repos/os/src/server/cached_fs_rom/main.cc
 @@ -13,6 +13,7 @@
@@ -734,3 +737,47 @@ index 5f2aea63f5..59dc2c7d98 100755
 -- 
 2.28.0
 
+
+From c98ba6fd70938804833e5c65a18d01c60f5be17f Mon Sep 17 00:00:00 2001
+From: Emery Hemingway <ehmry@posteo.net>
+Date: Thu, 5 Nov 2020 21:22:31 +0100
+Subject: [PATCH 3/3] cached_fs_rom: do not apply directory for absolute ROMs
+
+If the ROM name starts with / then do not apply a directory policy.
+---
+ repos/os/src/server/cached_fs_rom/main.cc | 15 ++++++++-------
+ 1 file changed, 8 insertions(+), 7 deletions(-)
+
+diff --git a/repos/os/src/server/cached_fs_rom/main.cc b/repos/os/src/server/cached_fs_rom/main.cc
+index 8df3001111..4479b41e87 100755
+--- a/repos/os/src/server/cached_fs_rom/main.cc
++++ b/repos/os/src/server/cached_fs_rom/main.cc
+@@ -450,17 +450,18 @@ struct Cached_fs_rom::Main final : Genode::Session_request_handler
+ 		 ** Find ROM in cache **
+ 		 ***********************/
+ 
++		Path path;
+ 
+-		Path path("/");
+-		Session_label const label = label_from_args(args.string());
++		auto const label = label_from_args(args.string());
++		auto const rom_name = label.last_element();
+ 
+ 		try {
+ 			Session_policy policy(label, config_rom.xml());
+-			path.append(policy.attribute_value(
+-				"directory", String<Path::capacity()>("/")).string());
+-		} catch (Service_denied) { }
+-
+-		path.append_element(label.last_element().string());
++			auto dir = policy.attribute_value("directory", String<Path::capacity()>("/"));
++			path = Path(rom_name.string(), dir.string());
++		} catch (Service_denied) {
++			path = Path(rom_name.string());
++		}
+ 
+ 		bool diag = session_diag_from_args(args.string()).enabled;
+ 
+-- 
+2.28.0
+