workbench/network/stacks/AROSTCP/netlib/access.c

   1 /* $Id$
   2  *
   3  *      access.c - check access to a file or a directory
   4  *
   5  *      Copyright © 1994 AmiTCP/IP Group,
   6  *                       Network Solutions Development Inc.
   7  *                       All rights reserved.
   8  */
   9
  10 #include <stdio.h>
  11 #include <stdlib.h>
  12 #include <dos.h>
  13 #include <string.h>
  14 #include <errno.h>
  15 #include <dos/dos.h>
  16 #include <proto/dos.h>
  17 #include <proto/exec.h>
  18 #include <exec/memory.h>
  19
  20 #include <bsdsocket.h>
  21
  22 /*
  23  * I know, the goto's are ugly, but they make the code smaller and help
  24  * to prevent duplicating code.
  25  */
  26 int
  27 access(const char *name, int mode)
  28 {
  29   BPTR    lock, parentLock;
  30   LONG    prot;
  31   UBYTE   bytes[sizeof(struct FileInfoBlock) + sizeof(struct InfoData) + 3];
  32   struct FileInfoBlock *fib;
  33   struct InfoData      *info;
  34
  35   /*
  36    * align the data areas
  37    */
  38   fib = (struct FileInfoBlock *) (((ULONG) bytes+3) & (0xFFFFFFFF-3));
  39   info = (struct InfoData *) (ULONG)(fib + 1);
  40
  41   /*
  42    * Lock the file (or directory)
  43    */
  44   if ((lock = Lock((STRPTR)name, SHARED_LOCK)) == NULL)
  45     goto osfail;
  46
  47   if (!Examine(lock, fib))
  48     goto osfail;
  49
  50   prot = fib->fib_Protection;
  51
  52   /*
  53    * Check each access mode
  54    */
  55   if (mode & R_OK && prot & FIBF_READ) {
  56     errno = EACCES;
  57     goto fail;
  58   }
  59   if (mode & W_OK) {
  60     /*
  61      * Check for write protected disks
  62      */
  63     if (!Info(lock, info))
  64       goto osfail;
  65
  66     if (info->id_DiskState == ID_WRITE_PROTECTED) {
  67       errno = EROFS;
  68       goto fail;
  69     }
  70
  71     /*
  72      * not write protected: Check if the lock is to the root of the
  73      * disk, if it is, force writing to be allowed.
  74      * Check if the lock is a directory before taking ParentDir()
  75      */
  76     if (fib->fib_DirEntryType >= 0) { /* lock is a directory */
  77       parentLock = ParentDir(lock);
  78       if (parentLock != NULL)
  79         UnLock(parentLock); /* not the root, prot is valid */
  80       else
  81         prot &= ~FIBF_WRITE; /* the root, force writing to be allowed */
  82     }
  83     if (prot & FIBF_WRITE) {
  84       errno = EACCES;
  85       goto fail;
  86     }
  87   }
  88   if (mode & X_OK && prot & FIBF_EXECUTE) {
  89     errno = EACCES;
  90     goto fail;
  91   }
  92
  93   /* F_OK */
  94
  95   UnLock(lock);
  96   return 0;
  97
  98  osfail:
  99 #if __SASC
 100   errno = __io2errno(_OSERR = IoErr());
 101 #else
 102   _ug_set_errno(IoErr());
 103 #endif
 104
 105  fail:
 106   if (lock != NULL)
 107     UnLock(lock);
 108
 109   return -1;
 110 }