Support setgid directories in tmpfs and kernfs

PiperOrigin-RevId: 356868412

2 files changed, 13 insertions, 8 deletions

diff --git a/test/syscalls/BUILD b/test/syscalls/BUILD
index d6658898d..9adb1cea3 100644
--- a/test/syscalls/BUILD
+++ b/test/syscalls/BUILD
@@ -89,7 +89,7 @@ syscall_test(
     size = "medium",
     add_overlay = True,
     test = "//test/syscalls/linux:chown_test",
-    use_tmpfs = True,  # chwon tests require gofer to be running as root.
+    use_tmpfs = True,  # chown tests require gofer to be running as root.
 )
 
 syscall_test(
@@ -557,7 +557,11 @@ syscall_test(
 )
 
 syscall_test(
+    add_overlay = True,
     test = "//test/syscalls/linux:setgid_test",
+    # setgid tests require the gofer's user namespace to have multiple groups,
+    # but bazel only provides one.
+    use_tmpfs = True,
 )
 
 syscall_test(
diff --git a/test/syscalls/linux/setgid.cc b/test/syscalls/linux/setgid.cc
index bfd91ba4f..cd030b094 100644
--- a/test/syscalls/linux/setgid.cc
+++ b/test/syscalls/linux/setgid.cc
@@ -86,7 +86,7 @@ class SetgidDirTest : public ::testing::Test {
     original_gid_ = getegid();
 
     // TODO(b/175325250): Enable when setgid directories are supported.
-    SKIP_IF(IsRunningOnGvisor());
+    SKIP_IF(IsRunningWithVFS1());
     SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveCapability(CAP_SETGID)));
 
     temp_dir_ = ASSERT_NO_ERRNO_AND_VALUE(
@@ -305,9 +305,7 @@ struct FileModeTestcase {
 class FileModeTest : public ::testing::TestWithParam<FileModeTestcase> {};
 
 TEST_P(FileModeTest, WriteToFile) {
-  // TODO(b/175325250): Enable when setgid directories are supported.
-  SKIP_IF(IsRunningOnGvisor());
-
+  SKIP_IF(IsRunningWithVFS1());
   auto temp_dir = ASSERT_NO_ERRNO_AND_VALUE(
       TempPath::CreateDirWith(GetAbsoluteTestTmpdir(), 0777 /* mode */));
   auto path = JoinPath(temp_dir.path(), GetParam().name);
@@ -330,9 +328,7 @@ TEST_P(FileModeTest, WriteToFile) {
 }
 
 TEST_P(FileModeTest, TruncateFile) {
-  // TODO(b/175325250): Enable when setgid directories are supported.
-  SKIP_IF(IsRunningOnGvisor());
-
+  SKIP_IF(IsRunningWithVFS1());
   auto temp_dir = ASSERT_NO_ERRNO_AND_VALUE(
       TempPath::CreateDirWith(GetAbsoluteTestTmpdir(), 0777 /* mode */));
   auto path = JoinPath(temp_dir.path(), GetParam().name);
@@ -343,6 +339,11 @@ TEST_P(FileModeTest, TruncateFile) {
   ASSERT_THAT(fstat(fd.get(), &stats), SyscallSucceeds());
   EXPECT_EQ(stats.st_mode & kDirmodeMask, GetParam().mode);
 
+  // Write something to the file, as truncating an empty file is a no-op.
+  constexpr char c = 'M';
+  ASSERT_THAT(write(fd.get(), &c, sizeof(c)),
+              SyscallSucceedsWithValue(sizeof(c)));
+
   // For security reasons, truncating the file clears the SUID bit, and clears
   // the SGID bit when the group executable bit is unset (which is not a true
   // SGID binary).