reactos/base/shell/cmd/redir.c

   1 /*
   2  *  REDIR.C - redirection handling.
   3  *
   4  *
   5  *  History:
   6  *
   7  *    12/15/95 (Tim Norman)
   8  *        started.
   9  *
  10  *    12 Jul 98 (Hans B Pufal)
  11  *        Rewrote to make more efficient and to conform to new command.c
  12  *        and batch.c processing.
  13  *
  14  *    27-Jul-1998 (John P Price <linux-guru@gcfl.net>)
  15  *        Added config.h include
  16  *
  17  *    22-Jan-1999 (Eric Kohl)
  18  *        Unicode safe!
  19  *        Added new error redirection "2>" and "2>>".
  20  *
  21  *    26-Jan-1999 (Eric Kohl)
  22  *        Added new error AND output redirection "&>" and "&>>".
  23  *
  24  *    24-Jun-2005 (Brandon Turner <turnerb7@msu.edu>)
  25  *        simple check to fix > and | bug with 'rem'
  26  */
  27
  28 #include <precomp.h>
  29
  30 #ifdef FEATURE_REDIRECTION
  31
  32
  33 /* cmd allows redirection of handles numbered 3-9 even though these don't
  34  * correspond to any STD_ constant. */
  35 static HANDLE ExtraHandles[10 - 3];
  36
  37 static HANDLE GetHandle(UINT Number)
  38 {
  39         if (Number < 3)
  40                 return GetStdHandle(STD_INPUT_HANDLE - Number);
  41         else
  42                 return ExtraHandles[Number - 3];
  43 }
  44
  45 static VOID SetHandle(UINT Number, HANDLE Handle)
  46 {
  47         if (Number < 3)
  48                 SetStdHandle(STD_INPUT_HANDLE - Number, Handle);
  49         else
  50                 ExtraHandles[Number - 3] = Handle;
  51 }
  52
  53 BOOL
  54 PerformRedirection(REDIRECTION *RedirList)
  55 {
  56         REDIRECTION *Redir;
  57         LPTSTR Filename;
  58         HANDLE hNew;
  59         UINT DupNumber;
  60
  61         static SECURITY_ATTRIBUTES SecAttr = { sizeof(SECURITY_ATTRIBUTES), NULL, TRUE };
  62
  63         /* Some parameters used for read, write, and append, respectively */
  64         static
  65         struct REDIR_PARAMS
  66         {
  67                 DWORD dwDesiredAccess;
  68                 DWORD dwShareMode;
  69                 DWORD dwCreationDisposition;
  70         } RedirParams[] =
  71         {
  72                 {GENERIC_READ , FILE_SHARE_READ | FILE_SHARE_WRITE, OPEN_EXISTING}, // REDIR_READ
  73                 {GENERIC_WRITE, FILE_SHARE_READ                   , CREATE_ALWAYS}, // REDIR_WRITE
  74                 {GENERIC_WRITE, FILE_SHARE_READ                   , OPEN_ALWAYS  }  // REDIR_APPEND
  75         };
  76
  77         for (Redir = RedirList; Redir; Redir = Redir->Next)
  78         {
  79                 Filename = DoDelayedExpansion(Redir->Filename);
  80                 if (!Filename)
  81                         goto redir_error;
  82                 StripQuotes(Filename);
  83
  84                 if (*Filename == _T('&'))
  85                 {
  86                         DupNumber = Filename[1] - _T('0');
  87                         if (DupNumber >= 10 ||
  88                             !DuplicateHandle(GetCurrentProcess(),
  89                                              GetHandle(DupNumber),
  90                                              GetCurrentProcess(),
  91                                              &hNew,
  92                                              0,
  93                                              TRUE,
  94                                              DUPLICATE_SAME_ACCESS))
  95                         {
  96                                 hNew = INVALID_HANDLE_VALUE;
  97                         }
  98                 }
  99                 else
 100                 {
 101                         hNew = CreateFile(Filename,
 102                                           RedirParams[Redir->Mode].dwDesiredAccess,
 103                                           RedirParams[Redir->Mode].dwShareMode,
 104                                           &SecAttr,
 105                                           RedirParams[Redir->Mode].dwCreationDisposition,
 106                                           0,
 107                                           NULL);
 108                 }
 109
 110                 if (hNew == INVALID_HANDLE_VALUE)
 111                 {
 112                         /* TODO: Print a more detailed message */
 113                         ConErrResPrintf(Redir->Mode == REDIR_READ ? STRING_CMD_ERROR1 : STRING_CMD_ERROR3,
 114                                         Filename);
 115                         cmd_free(Filename);
 116 redir_error:
 117                         /* Undo all the redirections before this one */
 118                         UndoRedirection(RedirList, Redir);
 119                         return FALSE;
 120                 }
 121
 122                 if (Redir->Mode == REDIR_APPEND)
 123                         SetFilePointer(hNew, 0, NULL, FILE_END);
 124                 Redir->OldHandle = GetHandle(Redir->Number);
 125                 SetHandle(Redir->Number, hNew);
 126
 127                 TRACE("%d redirected to: %s\n", Redir->Number, debugstr_aw(Filename));
 128                 cmd_free(Filename);
 129         }
 130         return TRUE;
 131 }
 132
 133 VOID
 134 UndoRedirection(REDIRECTION *Redir, REDIRECTION *End)
 135 {
 136         for (; Redir != End; Redir = Redir->Next)
 137         {
 138                 CloseHandle(GetHandle(Redir->Number));
 139                 SetHandle(Redir->Number, Redir->OldHandle);
 140                 Redir->OldHandle = INVALID_HANDLE_VALUE;
 141         }
 142 }
 143
 144 VOID
 145 FreeRedirection(REDIRECTION *Redir)
 146 {
 147         REDIRECTION *Next;
 148         for (; Redir; Redir = Next)
 149         {
 150                 Next = Redir->Next;
 151                 ASSERT(Redir->OldHandle == INVALID_HANDLE_VALUE);
 152                 cmd_free(Redir);
 153         }
 154 }
 155
 156 #endif /* FEATURE_REDIRECTION */