Adding new isSymLink() function

native/issymlink.cpp

@@ -0,0 +1,108 @@
+//! @file isSymLink.cpp
+//! @author George FLeming <v-geflem@microsoft.com>
+//! @brief returns whether a path is a symbolic link
+
+#include <errno.h>
+#include <langinfo.h>
+#include <locale.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <string>
+#include <unicode/unistr.h>
+#include "issymlink.h"
+
+//! @brief IsSymLink determines if path is a symbolic link 
+//!
+//! IsSymLink
+//!
+//! @param[in] fileName
+//! @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 these errors via errno to GetLastError:
+//! - ERROR_INVALID_PARAMETER: parameter is not valid
+//! - ERROR_BAD_ENVIRONMENT: locale is not UTF-8
+//! - ERROR_FILE_NOT_FOUND: file does not exist
+//! - ERROR_ACCESS_DENIED: access is denied
+//! - ERROR_FILE_NOT_FOUND: the system cannot find the file specified
+//! - ERROR_INVALID_ADDRESS: attempt to access invalid address
+//! - ERROR_STOPPED_ON_SYMLINK: the operation stopped after reaching a symbolic link
+//! - ERROR_GEN_FAILURE: device attached to the system is not functioning
+//! - ERROR_NO_SUCH_USER: there was no corresponding entry in the utmp-file
+//! - ERROR_INVALID_NAME: filename, directory name, or volume label syntax is incorrect
+//! - ERROR_BUFFER_OVERFLOW:  file name is too long
+//! - ERROR_INVALID_FUNCTION: incorrect function
+//! - ERROR_BAD_PATH_NAME: pathname is too long, or contains invalid characters
+//!
+//! @retval 1 if path is a symbolic link
+//! @retval 0 if path is not a symbolic link
+//! @retval -1 If the function fails.. To get extended error information, call GetLastError.
+//!
+
+long IsSymLink(const char* fileName)
+{
+    errno = 0;
+
+    // Check parameters
+    if (!fileName)
+    {
+        errno = ERROR_INVALID_PARAMETER;
+        return -1;
+    }
+
+    // Select locale from environment
+    setlocale(LC_ALL, "");
+    // Check that locale is UTF-8
+    if (nl_langinfo(CODESET) != std::string("UTF-8"))
+    {
+        errno = ERROR_BAD_ENVIRONMENT;
+        return -1;
+    }
+
+    struct stat statBuf;
+
+    int returnCode = lstat(fileName, &statBuf);
+
+    if  (returnCode != 0)
+    {
+        switch(errno)
+        {
+        case EACCES:
+            errno = ERROR_ACCESS_DENIED;
+            break;
+        case EBADF:
+            errno = ERROR_FILE_NOT_FOUND;
+            break;
+        case EFAULT:
+            errno = ERROR_INVALID_ADDRESS;
+            break;
+        case ELOOP:
+            errno = ERROR_STOPPED_ON_SYMLINK;
+            break;
+        case ENAMETOOLONG:
+            errno = ERROR_GEN_FAILURE;
+            break;
+        case ENOENT:
+            errno = ERROR_FILE_NOT_FOUND;
+            break;
+        case ENOMEM:
+            errno = ERROR_NO_SUCH_USER;
+            break;
+        case ENOTDIR:
+            errno = ERROR_INVALID_NAME;
+            break;
+        case EOVERFLOW:
+            errno = ERROR_BUFFER_OVERFLOW;
+            break;
+        default:
+            errno = ERROR_INVALID_FUNCTION;
+        }
+        return -1;
+    }
+
+    return S_ISLNK(statBuf.st_mode) ? 1 : 0;
+}