From 140bb4927aff197ccec5174d00d7442887db1245 Mon Sep 17 00:00:00 2001
From: Alan Somers <asomers@FreeBSD.org>
Date: Fri, 5 Apr 2019 15:33:43 +0000
Subject: [PATCH] fusefs: correctly return EROFS from VOP_ACCESS

Sponsored by:	The FreeBSD Foundation
---
 sys/fs/fuse/fuse_internal.c   |  2 +-
 tests/sys/fs/fusefs/access.cc | 21 +++++++++++++++++++++
 tests/sys/fs/fusefs/mockfs.cc |  6 +++++-
 tests/sys/fs/fusefs/mockfs.hh |  2 +-
 tests/sys/fs/fusefs/utils.cc  |  2 +-
 tests/sys/fs/fusefs/utils.hh  |  4 +++-
 6 files changed, 32 insertions(+), 5 deletions(-)

diff --git a/sys/fs/fuse/fuse_internal.c b/sys/fs/fuse/fuse_internal.c
index 52f0d80e335d..7c548b44f6d3 100644
--- a/sys/fs/fuse/fuse_internal.c
+++ b/sys/fs/fuse/fuse_internal.c
@@ -137,7 +137,7 @@ fuse_internal_access(struct vnode *vp,
 	dataflags = data->dataflags;
 
 	if ((mode & VWRITE) && vfs_isrdonly(mp)) {
-		return EACCES;
+		return EROFS;
 	}
 	/* Unless explicitly permitted, deny everyone except the fs owner. */
 	    if (vnode_isvroot(vp) && !(facp->facc_flags & FACCESS_NOCHECKSPY)) {
diff --git a/tests/sys/fs/fusefs/access.cc b/tests/sys/fs/fusefs/access.cc
index 016d9bcd8d8d..e36b0005bcda 100644
--- a/tests/sys/fs/fusefs/access.cc
+++ b/tests/sys/fs/fusefs/access.cc
@@ -46,6 +46,14 @@ void expect_lookup(const char *relpath, uint64_t ino)
 }
 };
 
+class RofsAccess: public Access {
+public:
+virtual void SetUp() {
+	m_ro = true;
+	Access::SetUp();
+}
+};
+
 /* The error case of FUSE_ACCESS.  */
 /* https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=236291 */
 TEST_F(Access, DISABLED_eaccess)
@@ -83,6 +91,19 @@ TEST_F(Access, DISABLED_enosys)
 	ASSERT_EQ(0, access(FULLPATH, access_mode)) << strerror(errno);
 }
 
+TEST_F(RofsAccess, erofs)
+{
+	const char FULLPATH[] = "mountpoint/some_file.txt";
+	const char RELPATH[] = "some_file.txt";
+	uint64_t ino = 42;
+	mode_t	access_mode = W_OK;
+
+	expect_lookup(RELPATH, ino);
+
+	ASSERT_NE(0, access(FULLPATH, access_mode));
+	ASSERT_EQ(EROFS, errno);
+}
+
 /* The successful case of FUSE_ACCESS.  */
 /* https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=236291 */
 TEST_F(Access, DISABLED_ok)
diff --git a/tests/sys/fs/fusefs/mockfs.cc b/tests/sys/fs/fusefs/mockfs.cc
index 5517ecc4f473..ec2c9b3a13c8 100644
--- a/tests/sys/fs/fusefs/mockfs.cc
+++ b/tests/sys/fs/fusefs/mockfs.cc
@@ -258,7 +258,7 @@ void debug_fuseop(const mockfs_buf_in *in)
 }
 
 MockFS::MockFS(int max_readahead, bool allow_other, bool default_permissions,
-	bool push_symlinks_in, uint32_t flags)
+	bool push_symlinks_in, bool ro, uint32_t flags)
 {
 	struct iovec *iov = NULL;
 	int iovlen = 0;
@@ -307,6 +307,10 @@ MockFS::MockFS(int max_readahead, bool allow_other, bool default_permissions,
 		build_iovec(&iov, &iovlen, "push_symlinks_in",
 			__DECONST(void*, &trueval), sizeof(bool));
 	}
+	if (ro) {
+		build_iovec(&iov, &iovlen, "ro",
+			__DECONST(void*, &trueval), sizeof(bool));
+	}
 	if (nmount(iov, iovlen, 0))
 		throw(std::system_error(errno, std::system_category(),
 			"Couldn't mount filesystem"));
diff --git a/tests/sys/fs/fusefs/mockfs.hh b/tests/sys/fs/fusefs/mockfs.hh
index ac4c9a030e3b..52121f92331b 100644
--- a/tests/sys/fs/fusefs/mockfs.hh
+++ b/tests/sys/fs/fusefs/mockfs.hh
@@ -216,7 +216,7 @@ class MockFS {
 
 	/* Create a new mockfs and mount it to a tempdir */
 	MockFS(int max_readahead, bool allow_other,
-		bool default_permissions, bool push_symlinks_in,
+		bool default_permissions, bool push_symlinks_in, bool ro,
 		uint32_t flags);
 	virtual ~MockFS();
 
diff --git a/tests/sys/fs/fusefs/utils.cc b/tests/sys/fs/fusefs/utils.cc
index e00b9d3c148b..ec7374bf34e7 100644
--- a/tests/sys/fs/fusefs/utils.cc
+++ b/tests/sys/fs/fusefs/utils.cc
@@ -94,7 +94,7 @@ void FuseTest::SetUp() {
 
 	try {
 		m_mock = new MockFS(m_maxreadahead, m_allow_other,
-			m_default_permissions, m_push_symlinks_in,
+			m_default_permissions, m_push_symlinks_in, m_ro,
 			m_init_flags);
 	} catch (std::system_error err) {
 		FAIL() << err.what();
diff --git a/tests/sys/fs/fusefs/utils.hh b/tests/sys/fs/fusefs/utils.hh
index 4022be7da302..b9114ab16180 100644
--- a/tests/sys/fs/fusefs/utils.hh
+++ b/tests/sys/fs/fusefs/utils.hh
@@ -44,6 +44,7 @@ class FuseTest : public ::testing::Test {
 	bool m_allow_other;
 	bool m_default_permissions;
 	bool m_push_symlinks_in;
+	bool m_ro;
 	MockFS *m_mock = NULL;
 	const static uint64_t FH = 0xdeadbeef1a7ebabe;
 
@@ -59,7 +60,8 @@ class FuseTest : public ::testing::Test {
 		m_init_flags(0),
 		m_allow_other(false),
 		m_default_permissions(false),
-		m_push_symlinks_in(false)
+		m_push_symlinks_in(false),
+		m_ro(false)
 	{}
 
 	virtual void SetUp();