Merge pull request 102 from dev/9-getcomputername into develop

impl/getcomputername.cpp

@@ -0,0 +1,127 @@
+//! @file getcomputername.cpp
+//! @author Aaron Katz <v-aakatz@microsoft.com>
+//! @brief Implements GetComputerName Win32 API
+
+#include <errno.h>
+#include <langinfo.h>
+#include <locale.h>
+#include <unistd.h>
+#include <string>
+#include <unicode/unistr.h>
+#include "getcomputername.h"
+
+//! @brief GetComputerName retrieves the name of the host associated with
+//! the current thread.
+//!
+//! GetComputerNameW is the Unicode variation. See [MSDN documentation].
+//!
+//! @param[out] lpBuffer
+//! @parblock
+//! A pointer to the buffer to receive the hosts's
+//! name. If this buffer is not large enough to contain the
+//! entire user hosts name, the function fails.
+//!
+//! WCHAR_T* is a Unicode [LPTSTR].
+//! @endparblock
+//!
+//! @param[in, out] lpnSize
+//! @parblock
+//! On input, this variable specifies the size of the lpBuffer buffer,
+//! in TCHARs. On output, the variable receives the number of TCHARs
+//! copied to the buffer, including the terminating null character.
+//!
+//! TCHAR is a Unicode 16-bit [WCHAR].
+//!
+//! If lpBuffer is too small, the function fails and GetLastError
+//! returns ERROR_INSUFFICIENT_BUFFER. This parameter receives the
+//! required buffer size, including the terminating null character.
+//! @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_TOO_MANY_OPEN_FILES: already have the maximum allowed number of open files
+//! - ERROR_NO_ASSOCIATION: calling process has no controlling terminal
+//! - ERROR_INSUFFICIENT_BUFFER: buffer not large enough to hold username string
+//! - ERROR_NO_SUCH_USER: there was no corresponding entry in the utmp-file
+//! - ERROR_OUTOFMEMORY: insufficient memory to allocate passwd structure
+//! - ERROR_NO_ASSOCIATION: standard input didn't refer to a terminal
+//! - ERROR_INVALID_FUNCTION: getlogin_r() returned an unrecognized error code
+//!
+//! @retval TRUE If the function succeeds, the return value is a nonzero
+//! value, and the variable pointed to by lpnSize contains the number
+//! of TCHARs copied to the buffer specified by lpBuffer, including
+//! the terminating null character.
+//!
+//! @retval FALSE If the function fails, the return value is zero. To get
+//! extended error information, call GetLastError.
+//!
+//! [MSDN documentation]: https://msdn.microsoft.com/en-us/library/windows/desktop/ms724295%28v=vs.85%29.aspx
+//! [WCHAR]: https://msdn.microsoft.com/en-us/library/windows/desktop/aa383751(v=vs.85).aspx#WCHAR
+//! [LPTSTR]: https://msdn.microsoft.com/en-us/library/windows/desktop/aa383751(v=vs.85).aspx#LPTSTR
+BOOL GetComputerNameW(WCHAR_T* lpBuffer, LPDWORD lpnSize)
+{
+    errno = 0;
+    
+    // Check parameters
+    if (!lpBuffer || !lpnSize) 
+    {
+        errno = ERROR_INVALID_PARAMETER;
+        return FALSE;
+    }
+    
+    // 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 FALSE;
+    }
+    
+    // Get computername from system in a thread-safe manner
+    std::string computername(HOST_NAME_MAX, 0);
+    int err = gethostname(&computername[0], computername.length());
+    // Map errno to Win32 Error Codes
+    if (err != 0) 
+    {
+        switch (errno) 
+        {
+            case EFAULT:
+                errno = ERROR_INVALID_ADDRESS;
+                break;
+            case ENAMETOOLONG:
+                errno = ERROR_GEN_FAILURE;
+                break; 
+            default:
+                errno = ERROR_INVALID_FUNCTION;
+        }
+        return FALSE;
+    }
+    
+    // Convert to UnicodeString
+    auto computername16 = icu::UnicodeString::fromUTF8(computername.c_str());
+    // Terminate string with null
+    computername16.append('\0');
+    
+    // Size in WCHARs including null
+    const DWORD size = computername16.length();
+    
+    //Check if parameters passed enough buffer space
+    if (size > *lpnSize)
+    {
+        errno = ERROR_INSUFFICIENT_BUFFER;
+        // Set lpnSize if buffer is too small to inform user
+        // of necessary size
+        *lpnSize= size;
+        return FALSE;
+    }
+    
+    // Extract string as UTF-16LE to buffer
+    computername16.extract(0, size, reinterpret_cast<char*>(lpBuffer), "UTF-16LE");
+    
+    *lpnSize = size;
+    return TRUE;
+    
+}
+

impl/getcomputername.h

@@ -0,0 +1,9 @@
+#pragma once
+
+#include "pal.h"
+
+PAL_BEGIN_EXTERNC
+
+BOOL GetComputerNameW(WCHAR_T* lpBuffer, LPDWORD lpnSize);
+
+PAL_END_EXTERNC

impl/pal.h

@@ -78,6 +78,8 @@
     #define ERROR_NO_SUCH_USER 0x00000525
     #define ERROR_INVALID_FUNCTION 0x00000001
     #define MAX_PATH 0x00000104
+    #define ERROR_INVALID_ADDRESS 0x000001e7
+    #define ERROR_GEN_FAILURE 0x0000001F
     typedef unsigned long long uint64;
 #endif