Add bool IsDirectory(char*) to libpsl-native

src/libpsl-native/src/CMakeLists.txt

@@ -8,6 +8,7 @@ add_library(psl-native SHARED
   getcomputername.cpp
   getlinkcount.cpp
   getfullyqualifiedname.cpp
+  isdirectory.cpp
   issymlink.cpp
   isexecutable.cpp
   setdate.cpp

src/libpsl-native/src/isdirectory.cpp

@@ -0,0 +1,51 @@
+//! @file isdirectory.cpp
+//! @author Andrew Schwartzmeyer <andschwa@microsoft.com>
+//! @brief returns if the path is a directory
+
+#include <errno.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <pwd.h>
+#include <string.h>
+#include <unistd.h>
+#include "getstat.h"
+#include "getpwuid.h"
+#include "getfileowner.h"
+#include "isdirectory.h"
+
+//! @brief returns if the path is a directory; uses stat and so follows symlinks
+//!
+//! IsDirectory
+//!
+//! @param[in] path
+//! @parblock
+//! A pointer to the buffer that contains the file name
+//!
+//! char* is marshaled as an LPStr, which on Linux is UTF-8.
+//! @endparblock
+//!
+//! @exception errno Passes this error via errno to GetLastError:
+//! - ERROR_INVALID_PARAMETER: parameter is not valid
+//!
+//! @retval true if directory, false otherwise
+//!
+bool IsDirectory(const char* path)
+{
+    int32_t ret = 0;
+    errno = 0;
+
+    if (!path)
+    {
+        errno = ERROR_INVALID_PARAMETER;
+        return false;
+    }
+
+    struct stat buf;
+    ret = GetStat(path, &buf);
+    if (ret != 0)
+    {
+        return false;
+    }
+
+    return S_ISDIR(buf.st_mode);
+}

src/libpsl-native/src/isdirectory.h

@@ -0,0 +1,10 @@
+#pragma once
+
+#include "pal.h"
+#include <stdbool.h>
+
+PAL_BEGIN_EXTERNC
+
+bool IsDirectory(const char* path);
+
+PAL_END_EXTERNC

src/libpsl-native/test/CMakeLists.txt

@@ -9,6 +9,7 @@ add_executable(psl-native-test
   test-getcomputername.cpp
   test-getlinkcount.cpp
   test-getfullyqualifiedname.cpp
+  test-isdirectory.cpp
   test-issymlink.cpp
   test-isexecutable.cpp
   test-createsymlink.cpp

src/libpsl-native/test/test-isdirectory.cpp

@@ -0,0 +1,31 @@
+//! @file test-isdirectory.cpp
+//! @author Andrew Schwartzmeyer <andschwa@microsoft.com>
+//! @brief Tests IsDirectory
+
+#include <gtest/gtest.h>
+#include <errno.h>
+#include <unistd.h>
+#include "isdirectory.h"
+
+TEST(IsDirectoryTest, RootIsDirectory)
+{
+    EXPECT_TRUE(IsDirectory("/"));
+}
+
+TEST(IsDirectoryTest, BinLsIsNotDirectory)
+{
+    EXPECT_FALSE(IsDirectory("/bin/ls"));
+}
+
+
+TEST(IsDirectoryTest, ReturnsFalseForFakeDirectory)
+{
+    EXPECT_FALSE(IsDirectory("SomeMadeUpFileNameThatDoesNotExist"));
+    EXPECT_EQ(errno, ERROR_FILE_NOT_FOUND);
+}
+
+TEST(IsDirectoryTest, ReturnsFalseForNullInput)
+{
+    EXPECT_FALSE(IsDirectory(NULL));
+    EXPECT_EQ(errno, ERROR_INVALID_PARAMETER);
+}