Gate FUSE behind a runsc flag

This change gates all FUSE commands (by gating /dev/fuse) behind a runsc
flag. In order to use FUSE commands, use the --fuse flag with the --vfs2
flag. Check if FUSE is enabled by running dmesg in the sandbox.

2 files changed, 7 insertions, 0 deletions

diff --git a/test/util/test_util.cc b/test/util/test_util.cc
index 8a037f45f..d0c1d6426 100644
--- a/test/util/test_util.cc
+++ b/test/util/test_util.cc
@@ -42,6 +42,7 @@ namespace testing {
 
 constexpr char kGvisorNetwork[] = "GVISOR_NETWORK";
 constexpr char kGvisorVfs[] = "GVISOR_VFS";
+constexpr char kFuseEnabled[] = "FUSE_ENABLED";
 
 bool IsRunningOnGvisor() { return GvisorPlatform() != Platform::kNative; }
 
@@ -68,6 +69,11 @@ bool IsRunningWithVFS1() {
   return strcmp(env, "VFS1") == 0;
 }
 
+bool IsFUSEEnabled() {
+  const char* env = getenv(kFuseEnabled);
+  return env && strcmp(env, "TRUE") == 0;
+}
+
 // Inline cpuid instruction.  Preserve %ebx/%rbx register. In PIC compilations
 // %ebx contains the address of the global offset table. %rbx is occasionally
 // used to address stack variables in presence of dynamic allocas.
diff --git a/test/util/test_util.h b/test/util/test_util.h
index 109078fc7..89ac575bd 100644
--- a/test/util/test_util.h
+++ b/test/util/test_util.h
@@ -225,6 +225,7 @@ const std::string GvisorPlatform();
 bool IsRunningWithHostinet();
 // TODO(gvisor.dev/issue/1624): Delete once VFS1 is gone.
 bool IsRunningWithVFS1();
+bool IsFUSEEnabled();
 
 #ifdef __linux__
 void SetupGvisorDeathTest();