From 777724a09ba4000ec077154b4f13c77d8c875d63 Mon Sep 17 00:00:00 2001
From: Dan Goodliffe <dan@randomdan.homeip.net>
Date: Sun, 20 Sep 2020 15:53:29 +0100
Subject: Add the MaskUnknown mapper

---
 netfs/fuse/fuseMappers.ice     |  7 +++++++
 netfs/fuse/fuseMappersImpl.cpp | 42 ++++++++++++++++++++++++++++++++++++++++++
 netfs/fuse/fuseMappersImpl.h   | 14 ++++++++++++++
 netfs/unittests/testLib.cpp    | 42 ++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 105 insertions(+)

diff --git a/netfs/fuse/fuseMappers.ice b/netfs/fuse/fuseMappers.ice
index 6945eec..582aa16 100644
--- a/netfs/fuse/fuseMappers.ice
+++ b/netfs/fuse/fuseMappers.ice
@@ -7,6 +7,13 @@ module NetFS {
 		local class HideUnknownMapper extends Mapping::Mapper {
 
 		};
+		["slicer:implementation:NetFS.Client.MaskUnknownMapperImpl"]
+		local class MaskUnknownMapper extends Mapping::Mapper {
+			string UnknownUser = "nobody";
+			string UnknownGroup = "nogroup";
+			int MaskUser = 0700;
+			int MaskGroup = 0070;
+		};
 	};
 };
 
diff --git a/netfs/fuse/fuseMappersImpl.cpp b/netfs/fuse/fuseMappersImpl.cpp
index d22f3a4..4aa2789 100644
--- a/netfs/fuse/fuseMappersImpl.cpp
+++ b/netfs/fuse/fuseMappersImpl.cpp
@@ -38,4 +38,46 @@ namespace NetFS::Client {
 		}
 		return {u->name, g->name, 0};
 	}
+	MaskUnknownMapperImpl::MaskUnknownMapperImpl() : MaskUnknownMapperImpl(std::make_shared<UserEntCache>()) { }
+
+	MaskUnknownMapperImpl::MaskUnknownMapperImpl(EntryResolverPtr<User> u) :
+		MaskUnknownMapperImpl(std::move(u), std::make_shared<GroupEntCache>(u))
+	{
+	}
+
+	MaskUnknownMapperImpl::MaskUnknownMapperImpl(EntryResolverPtr<User> u, EntryResolverPtr<Group> g) :
+		users(std::move(u)), groups(std::move(g))
+	{
+	}
+
+	Mapping::FileSystem
+	MaskUnknownMapperImpl::mapTransport(const std::string & un, const std::string & gn)
+	{
+		int mask = 0;
+		auto apply = [&mask](const auto & resolver, const auto & entry, const auto & fallbackentry, auto entrymask) {
+			auto e = resolver->getEntry(entry);
+			if (!e) {
+				e = resolver->getEntry(fallbackentry);
+				if (!e) {
+					throw NetFS::SystemError(EPERM);
+				}
+				mask |= entrymask;
+			}
+			return e;
+		};
+		auto u = apply(users, un, UnknownUser, MaskUser);
+		auto g = apply(groups, gn, UnknownGroup, MaskGroup);
+		return {static_cast<int>(u->id), static_cast<int>(g->id), mask};
+	}
+
+	Mapping::Transport
+	MaskUnknownMapperImpl::mapFileSystem(int uid, int gid)
+	{
+		auto u = users->getEntry(uid);
+		auto g = groups->getEntry(gid);
+		if (!u || !g) {
+			throw NetFS::SystemError(EPERM);
+		}
+		return {u->name, g->name, 0};
+	}
 }
diff --git a/netfs/fuse/fuseMappersImpl.h b/netfs/fuse/fuseMappersImpl.h
index a0b1eb3..41d78b8 100644
--- a/netfs/fuse/fuseMappersImpl.h
+++ b/netfs/fuse/fuseMappersImpl.h
@@ -21,6 +21,20 @@ namespace NetFS {
 			EntryResolverPtr<User> users;
 			EntryResolverPtr<Group> groups;
 		};
+
+		class DLL_PUBLIC MaskUnknownMapperImpl : public MaskUnknownMapper {
+		public:
+			MaskUnknownMapperImpl();
+			MaskUnknownMapperImpl(EntryResolverPtr<User> u);
+			MaskUnknownMapperImpl(EntryResolverPtr<User> u, EntryResolverPtr<Group> g);
+
+			Mapping::Transport mapFileSystem(int uid, int gid) override;
+			Mapping::FileSystem mapTransport(const std::string & un, const std::string & gn) override;
+
+		protected:
+			EntryResolverPtr<User> users;
+			EntryResolverPtr<Group> groups;
+		};
 	}
 }
 
diff --git a/netfs/unittests/testLib.cpp b/netfs/unittests/testLib.cpp
index 29167c4..c99f582 100644
--- a/netfs/unittests/testLib.cpp
+++ b/netfs/unittests/testLib.cpp
@@ -155,3 +155,45 @@ BOOST_AUTO_TEST_CASE(bad_mapfilesystem)
 }
 
 BOOST_AUTO_TEST_SUITE_END();
+
+BOOST_FIXTURE_TEST_SUITE(mm, NetFS::Client::MaskUnknownMapperImpl);
+
+BOOST_AUTO_TEST_CASE(good_maptransport)
+{
+	auto fs = mapTransport("root", "root");
+	BOOST_CHECK_EQUAL(0, fs.uid);
+	BOOST_CHECK_EQUAL(0, fs.gid);
+	BOOST_CHECK_EQUAL(0, fs.mask);
+}
+
+BOOST_AUTO_TEST_CASE(good_mapfs)
+{
+	auto tn = mapFileSystem(0, 0);
+	BOOST_CHECK_EQUAL("root", tn.username);
+	BOOST_CHECK_EQUAL("root", tn.groupname);
+}
+
+BOOST_AUTO_TEST_CASE(bad_maptransport)
+{
+	BOOST_CHECK_EQUAL(mapTransport("root", "").mask, 0070);
+	BOOST_CHECK_EQUAL(mapTransport("", "root").mask, 0700);
+	BOOST_CHECK_EQUAL(mapTransport("", "").mask, 0770);
+}
+
+BOOST_AUTO_TEST_CASE(bad_maptransport_badfallback)
+{
+	UnknownUser = "not existing";
+	UnknownGroup = "not existing";
+	BOOST_REQUIRE_THROW(mapTransport("root", ""), NetFS::SystemError);
+	BOOST_REQUIRE_THROW(mapTransport("", "root"), NetFS::SystemError);
+	BOOST_REQUIRE_THROW(mapTransport("", ""), NetFS::SystemError);
+}
+
+BOOST_AUTO_TEST_CASE(bad_mapfilesystem)
+{
+	BOOST_REQUIRE_THROW(mapFileSystem(0, -1), NetFS::SystemError);
+	BOOST_REQUIRE_THROW(mapFileSystem(-1, 0), NetFS::SystemError);
+	BOOST_REQUIRE_THROW(mapFileSystem(-1, -1), NetFS::SystemError);
+}
+
+BOOST_AUTO_TEST_SUITE_END();
-- 
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