base/shell/cmd/mklink.c

   1 /*
   2  *  MKLINK.C - mklink internal command.
   3  */
   4
   5 #include "precomp.h"
   6
   7 #ifdef INCLUDE_CMD_MKLINK
   8
   9 /* There is no API for creating junctions, so we must do it the hard way */
  10 static BOOL CreateJunction(LPCTSTR LinkName, LPCTSTR TargetName)
  11 {
  12     /* Structure for reparse point daya when ReparseTag is one of
  13      * the tags defined by Microsoft. Copied from MinGW winnt.h */
  14     typedef struct _REPARSE_DATA_BUFFER
  15     {
  16         DWORD  ReparseTag;
  17         WORD   ReparseDataLength;
  18         WORD   Reserved;
  19         _ANONYMOUS_UNION union
  20         {
  21             struct
  22             {
  23                 WORD   SubstituteNameOffset;
  24                 WORD   SubstituteNameLength;
  25                 WORD   PrintNameOffset;
  26                 WORD   PrintNameLength;
  27                 ULONG  Flags;
  28                 WCHAR PathBuffer[1];
  29             } SymbolicLinkReparseBuffer;
  30             struct
  31             {
  32                 WORD   SubstituteNameOffset;
  33                 WORD   SubstituteNameLength;
  34                 WORD   PrintNameOffset;
  35                 WORD   PrintNameLength;
  36                 WCHAR PathBuffer[1];
  37             } MountPointReparseBuffer;
  38             struct
  39             {
  40                 BYTE   DataBuffer[1];
  41             } GenericReparseBuffer;
  42         } DUMMYUNIONNAME;
  43     } REPARSE_DATA_BUFFER, *PREPARSE_DATA_BUFFER;
  44
  45     HMODULE hNTDLL = GetModuleHandle(_T("NTDLL"));
  46     BOOLEAN (WINAPI *RtlDosPathNameToNtPathName_U)(PCWSTR, PUNICODE_STRING, PCWSTR *, CURDIR *)
  47         = (BOOLEAN (WINAPI *)(PCWSTR, PUNICODE_STRING, PCWSTR *, CURDIR *))GetProcAddress(hNTDLL, "RtlDosPathNameToNtPathName_U");
  48     VOID (WINAPI *RtlFreeUnicodeString)(PUNICODE_STRING)
  49         = (VOID (WINAPI *)(PUNICODE_STRING))GetProcAddress(hNTDLL, "RtlFreeUnicodeString");
  50
  51     TCHAR TargetFullPath[MAX_PATH];
  52 #ifdef UNICODE
  53     #define TargetFullPathW TargetFullPath
  54 #else
  55     WCHAR TargetFullPathW[MAX_PATH];
  56 #endif
  57     UNICODE_STRING TargetNTPath;
  58     HANDLE hJunction;
  59
  60     /* The data for this kind of reparse point has two strings:
  61      * The first ("SubstituteName") is the full target path in NT format,
  62      * the second ("PrintName") is the full target path in Win32 format.
  63      * Both of these must be wide-character strings. */
  64     if (!RtlDosPathNameToNtPathName_U ||
  65         !RtlFreeUnicodeString ||
  66         !GetFullPathName(TargetName, MAX_PATH, TargetFullPath, NULL) ||
  67 #ifndef UNICODE
  68         !MultiByteToWideChar(CP_ACP, 0, TargetFullPath, -1, TargetFullPathW, -1) ||
  69 #endif
  70         !RtlDosPathNameToNtPathName_U(TargetFullPathW, &TargetNTPath, NULL, NULL))
  71     {
  72         return FALSE;
  73     }
  74
  75     /* We have both the names we need, so time to create the junction.
  76      * Start with an empty directory */
  77     if (!CreateDirectory(LinkName, NULL))
  78     {
  79         RtlFreeUnicodeString(&TargetNTPath);
  80         return FALSE;
  81     }
  82
  83     /* Open the directory we just created */
  84     hJunction = CreateFile(LinkName, GENERIC_WRITE, 0, NULL,
  85         OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS, NULL);
  86     if (hJunction != INVALID_HANDLE_VALUE)
  87     {
  88         /* Allocate a buffer large enough to hold both strings, including trailing NULs */
  89         SIZE_T TargetLen = wcslen(TargetFullPathW) * sizeof(WCHAR);
  90         DWORD DataSize = (DWORD)(FIELD_OFFSET(REPARSE_DATA_BUFFER, MountPointReparseBuffer.PathBuffer)
  91                           + TargetNTPath.Length + sizeof(WCHAR)
  92                           + TargetLen           + sizeof(WCHAR));
  93         PREPARSE_DATA_BUFFER Data = _alloca(DataSize);
  94
  95         /* Fill it out and use it to turn the directory into a reparse point */
  96         Data->ReparseTag = IO_REPARSE_TAG_MOUNT_POINT;
  97         Data->ReparseDataLength = (WORD)(DataSize - FIELD_OFFSET(REPARSE_DATA_BUFFER, MountPointReparseBuffer));
  98         Data->Reserved = 0;
  99         Data->MountPointReparseBuffer.SubstituteNameOffset = 0;
 100         Data->MountPointReparseBuffer.SubstituteNameLength = TargetNTPath.Length;
 101         wcscpy(Data->MountPointReparseBuffer.PathBuffer,
 102                TargetNTPath.Buffer);
 103         Data->MountPointReparseBuffer.PrintNameOffset = TargetNTPath.Length + sizeof(WCHAR);
 104         Data->MountPointReparseBuffer.PrintNameLength = (USHORT)TargetLen;
 105         wcscpy((WCHAR *)((BYTE *)Data->MountPointReparseBuffer.PathBuffer
 106                          + Data->MountPointReparseBuffer.PrintNameOffset),
 107                         TargetFullPathW);
 108         if (DeviceIoControl(hJunction, FSCTL_SET_REPARSE_POINT,
 109                             Data, DataSize, NULL, 0, &DataSize, NULL))
 110         {
 111             /* Success */
 112             CloseHandle(hJunction);
 113             RtlFreeUnicodeString(&TargetNTPath);
 114             return TRUE;
 115         }
 116         CloseHandle(hJunction);
 117     }
 118     RemoveDirectory(LinkName);
 119     RtlFreeUnicodeString(&TargetNTPath);
 120     return FALSE;
 121 }
 122
 123 INT
 124 cmd_mklink(LPTSTR param)
 125 {
 126     HMODULE hKernel32 = GetModuleHandle(_T("KERNEL32"));
 127     DWORD Flags = 0;
 128     enum { SYMBOLIC, HARD, JUNCTION } LinkType = SYMBOLIC;
 129     INT NumFiles = 0;
 130     LPTSTR Name[2];
 131     INT argc, i;
 132     LPTSTR *arg;
 133
 134     if (!_tcsncmp(param, _T("/?"), 2))
 135     {
 136         ConOutResPuts(STRING_MKLINK_HELP);
 137         return 0;
 138     }
 139
 140     arg = split(param, &argc, FALSE, FALSE);
 141     for (i = 0; i < argc; i++)
 142     {
 143         if (arg[i][0] == _T('/'))
 144         {
 145             if (!_tcsicmp(arg[i], _T("/D")))
 146                 Flags |= 1; /* SYMBOLIC_LINK_FLAG_DIRECTORY */
 147             else if (!_tcsicmp(arg[i], _T("/H")))
 148                 LinkType = HARD;
 149             else if (!_tcsicmp(arg[i], _T("/J")))
 150                 LinkType = JUNCTION;
 151             else
 152             {
 153                 error_invalid_switch(arg[i][1]);
 154                 freep(arg);
 155                 return 1;
 156             }
 157         }
 158         else
 159         {
 160             if (NumFiles == 2)
 161             {
 162                 error_too_many_parameters(arg[i]);
 163                 freep(arg);
 164                 return 1;
 165             }
 166             Name[NumFiles++] = arg[i];
 167         }
 168     }
 169     freep(arg);
 170
 171     if (NumFiles != 2)
 172     {
 173         error_req_param_missing();
 174         return 1;
 175     }
 176
 177     nErrorLevel = 0;
 178
 179     if (LinkType == SYMBOLIC)
 180     {
 181         /* CreateSymbolicLink doesn't exist in old versions of Windows,
 182          * so load dynamically */
 183         BOOL (WINAPI *CreateSymbolicLink)(LPCTSTR, LPCTSTR, DWORD)
 184 #ifdef UNICODE
 185             = (BOOL (WINAPI *)(LPCTSTR, LPCTSTR, DWORD))GetProcAddress(hKernel32, "CreateSymbolicLinkW");
 186 #else
 187             = (BOOL (WINAPI *)(LPCTSTR, LPCTSTR, DWORD))GetProcAddress(hKernel32, "CreateSymbolicLinkA");
 188 #endif
 189         if (CreateSymbolicLink && CreateSymbolicLink(Name[0], Name[1], Flags))
 190         {
 191             ConOutResPrintf(STRING_MKLINK_CREATED_SYMBOLIC, Name[0], Name[1]);
 192             return 0;
 193         }
 194     }
 195     else if (LinkType == HARD)
 196     {
 197         /* CreateHardLink doesn't exist in old versions of Windows,
 198          * so load dynamically */
 199         BOOL (WINAPI *CreateHardLink)(LPCTSTR, LPCTSTR, LPSECURITY_ATTRIBUTES)
 200 #ifdef UNICODE
 201             = (BOOL (WINAPI *)(LPCTSTR, LPCTSTR, LPSECURITY_ATTRIBUTES))GetProcAddress(hKernel32, "CreateHardLinkW");
 202 #else
 203             = (BOOL (WINAPI *)(LPCTSTR, LPCTSTR, LPSECURITY_ATTRIBUTES))GetProcAddress(hKernel32, "CreateHardLinkA");
 204 #endif
 205         if (CreateHardLink && CreateHardLink(Name[0], Name[1], NULL))
 206         {
 207             ConOutResPrintf(STRING_MKLINK_CREATED_HARD, Name[0], Name[1]);
 208             return 0;
 209         }
 210     }
 211     else
 212     {
 213         if (CreateJunction(Name[0], Name[1]))
 214         {
 215             ConOutResPrintf(STRING_MKLINK_CREATED_JUNCTION, Name[0], Name[1]);
 216             return 0;
 217         }
 218     }
 219
 220     ErrorMessage(GetLastError(), _T("MKLINK"));
 221     return 1;
 222 }
 223
 224 #endif /* INCLUDE_CMD_MKLINK */