compiler/clib/access.c

   1 /*
   2     Copyright © 1995-2009, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     POSIX function access().
   6 */
   7
   8 #include <errno.h>
   9 #include <proto/dos.h>
  10 #include <dos/filesystem.h>
  11 #include <string.h>
  12
  13 #include <aros/debug.h>
  14
  15 #include "__errno.h"
  16 #include "__upath.h"
  17
  18 /*****************************************************************************
  19
  20     NAME */
  21 #include <unistd.h>
  22
  23         int access (
  24
  25 /*  SYNOPSIS */
  26         const char *path,
  27         int         mode)
  28
  29 /*  FUNCTION
  30         Check access permissions of a file or pathname
  31
  32     INPUTS
  33         path - the path of the file being checked
  34         mode - the bitwise inclusive OR of the access permissions
  35                to be checked:
  36
  37                W_OK - for write permission
  38                R_OK - for readpermissions
  39                X_OK - for execute permission
  40                F_OK - Just to see whether the file exists
  41
  42     RESULT
  43         If path cannot be found or if any of the desired access
  44         modes would not be granted, then a -1 value is returned;
  45         otherwise a 0 value is returned.
  46
  47     NOTES
  48
  49     EXAMPLE
  50
  51     BUGS
  52
  53     SEE ALSO
  54         open(), ftruncate()
  55
  56     INTERNALS
  57
  58 ******************************************************************************/
  59 {
  60     BPTR lock = NULL;
  61     struct FileInfoBlock *fib = NULL;
  62     int result = -1;
  63     char vol[32];
  64     struct DosList *dl = NULL;
  65
  66     if (!path) /* safety check */
  67     {
  68         errno = EFAULT;
  69         return -1;
  70     }
  71
  72     if (!strlen(path)) /* empty path */
  73     {
  74         errno = ENOENT;
  75         return -1;
  76     }
  77
  78     /* Check if the volume exists. Calling Lock on non-existing volume will bring up System Requester */
  79     if (SplitName(__path_u2a(path), ':', vol, 0, sizeof(vol)-1) != -1)
  80     {
  81         if(strcmp(vol, "PROGDIR") != 0)
  82         {
  83             dl = LockDosList(LDF_ALL | LDF_READ);
  84             dl = FindDosEntry(dl, vol, LDF_ALL);
  85             UnLockDosList(LDF_ALL | LDF_READ);
  86             /* Volume / Assign / Device not found */
  87             if (dl == NULL)
  88             {
  89                 errno = ENOENT;
  90                 return -1;
  91             }
  92         }
  93     }
  94
  95     /* Create a lock and examine a lock */
  96
  97     lock = Lock(__path_u2a(path), SHARED_LOCK);
  98     if (lock == NULL)
  99     {
 100         errno = IoErr2errno(IoErr());
 101         return -1;
 102     }
 103
 104     fib = AllocDosObject(DOS_FIB, NULL);
 105     if (!fib)
 106     {
 107         errno = IoErr2errno(IoErr());
 108         UnLock(lock);
 109         return -1;
 110     }
 111
 112     if (Examine(lock, fib))
 113     {
 114         /* Notice : protection flags are 'low-active' (0 means access is granted) */
 115         result = 0;
 116         if ((mode & R_OK) && (result == 0) && (fib->fib_Protection & (1 << FIBB_READ)))
 117         {
 118             errno = EACCES;
 119             result = -1;
 120         }
 121         if ((mode & W_OK) && (result == 0) && (fib->fib_Protection & (1 << FIBB_WRITE)))
 122         {
 123             errno = EACCES;
 124             result = -1;
 125         }
 126         if ((mode & X_OK) && (result == 0) && (fib->fib_Protection & (1 << FIBB_EXECUTE)))
 127         {
 128             errno = EACCES;
 129             result = -1;
 130         }
 131     }
 132     else
 133     {
 134         errno = EBADF;
 135         result = -1;
 136     }
 137
 138     FreeDosObject(DOS_FIB, fib);
 139     fib = NULL;
 140
 141     UnLock(lock);
 142     return result;
 143 }