Implement StatFS for various VFS2 filesystems.

This mainly involved enabling kernfs' client filesystems to provide a
StatFS implementation.

Fixes #3411, #3515.

PiperOrigin-RevId: 329009864

1 files changed, 17 insertions, 0 deletions

diff --git a/test/syscalls/linux/socket.cc b/test/syscalls/linux/socket.cc
index c20cd3fcc..e680d3dd7 100644
--- a/test/syscalls/linux/socket.cc
+++ b/test/syscalls/linux/socket.cc
@@ -14,6 +14,7 @@
 
 #include <sys/socket.h>
 #include <sys/stat.h>
+#include <sys/statfs.h>
 #include <sys/types.h>
 #include <unistd.h>
 
@@ -26,6 +27,9 @@
 namespace gvisor {
 namespace testing {
 
+// From linux/magic.h, but we can't depend on linux headers here.
+#define SOCKFS_MAGIC 0x534F434B
+
 TEST(SocketTest, UnixSocketPairProtocol) {
   int socks[2];
   ASSERT_THAT(socketpair(AF_UNIX, SOCK_STREAM, PF_UNIX, socks),
@@ -94,6 +98,19 @@ TEST(SocketTest, UnixSocketStat) {
   }
 }
 
+TEST(SocketTest, UnixSocketStatFS) {
+  SKIP_IF(IsRunningWithVFS1());
+
+  FileDescriptor bound =
+      ASSERT_NO_ERRNO_AND_VALUE(Socket(AF_UNIX, SOCK_STREAM, PF_UNIX));
+
+  struct statfs st;
+  EXPECT_THAT(fstatfs(bound.get(), &st), SyscallSucceeds());
+  EXPECT_EQ(st.f_type, SOCKFS_MAGIC);
+  EXPECT_EQ(st.f_bsize, getpagesize());
+  EXPECT_EQ(st.f_namelen, NAME_MAX);
+}
+
 using SocketOpenTest = ::testing::TestWithParam<int>;
 
 // UDS cannot be opened.