mex: is_admin()

Author: scivision

+stdlib/is_admin.m

@@ -0,0 +1 @@
+%% IS_ADMIN is the process run as root / admin (requires MEX)

private/get_mex_sources.m

@@ -15,10 +15,12 @@
 sym = fullfile(top, "src/symlink_fs.cpp");
 
 
-srcs = {fullfile(top, "src/is_char_device.cpp"), ...
-  fullfile(top, "src/set_permissions.cpp"), ...
-  [fullfile(top, "src/is_rosetta.cpp"), mac], ...
-  [fullfile(top, "src/windows_shortname.cpp"), win], ...
+srcs = {
+fullfile(top, "src/is_admin.cpp"), ...
+fullfile(top, "src/is_char_device.cpp"), ...
+fullfile(top, "src/set_permissions.cpp"), ...
+[fullfile(top, "src/is_rosetta.cpp"), mac], ...
+[fullfile(top, "src/windows_shortname.cpp"), win], ...
 };
 
 %%  new in R2024b

src/is_admin.cpp

@@ -0,0 +1,55 @@
+#include "mex.hpp"
+#include "mexAdapter.hpp"
+
+#include <vector>
+#include <memory>
+
+#if defined(_WIN32)
+#define WIN32_LEAN_AND_MEAN
+#include <windows.h>  // GetTokenInformation
+#else
+#include <unistd.h>  // geteuid
+#include <sys/types.h>  // geteuid, pid_t
+#endif
+
+
+static bool fs_is_admin(){
+  // running as admin / root / superuser
+#if defined(_WIN32)
+  HANDLE hToken = nullptr;
+  TOKEN_ELEVATION elevation;
+  DWORD dwSize;
+
+  const bool ok = (OpenProcessToken(GetCurrentProcess(), TOKEN_QUERY, &hToken) &&
+     GetTokenInformation(hToken, TokenElevation, &elevation, sizeof(elevation), &dwSize));
+
+  if(hToken)
+    CloseHandle(hToken);
+  if(ok)
+    return elevation.TokenIsElevated;
+
+  return false;
+#else
+  return geteuid() == 0;
+#endif
+}
+
+
+class MexFunction : public matlab::mex::Function {
+public:
+  void operator()(matlab::mex::ArgumentList outputs, matlab::mex::ArgumentList inputs) {
+// boilerplate engine & ArrayFactory setup
+    std::shared_ptr<matlab::engine::MATLABEngine> matlabEng = getEngine();
+    matlab::data::ArrayFactory factory;
+
+    if (inputs.size() != 0) {
+      matlabEng->feval(u"error", 0,
+        std::vector<matlab::data::Array>({ factory.createScalar("Mex: No input required") }));
+    }
+
+// actual function algorithm / computation
+    bool y = fs_is_admin();
+
+    outputs[0] = factory.createScalar<bool>(y);
+  }
+};

test/TestMex.m

@@ -3,9 +3,7 @@
 methods (Test)
 
 function test_is_char_device(tc)
-import matlab.unittest.fixtures.CurrentFolderFixture
-
-tc.applyFixture(CurrentFolderFixture(".."))
+tc.applyFixture(matlab.unittest.fixtures.CurrentFolderFixture(".."))
 % matlab exist() doesn't work for MEX detection with ".." leading path
 
 tc.assumeEqual(exist("+stdlib/is_char_device", "file"), 3)
@@ -18,7 +16,14 @@ function test_is_char_device(tc)
 end
 
 tc.verifyTrue(stdlib.is_char_device(n))
+end
+
+
+function test_is_admin(tc)
+tc.applyFixture(matlab.unittest.fixtures.CurrentFolderFixture(".."))
 
+tc.assumeEqual(exist("+stdlib/is_admin", "file"), 3)
+tc.verifyClass(stdlib.is_admin(), "logical")
 end
 
 end