compiler/clib/readlink.c

   1 /*
   2     Copyright © 1995-2010, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     ANSI C function readlink().
   6 */
   7
   8 #include <aros/debug.h>
   9
  10 #include <dos/filesystem.h>
  11 #include <proto/dos.h>
  12
  13 #include <errno.h>
  14
  15 #include "__arosc_privdata.h"
  16 #include "__errno.h"
  17 #include "__filesystem_support.h"
  18 #include "__upath.h"
  19
  20 /*****************************************************************************
  21
  22     NAME */
  23 #include <unistd.h>
  24
  25         ssize_t readlink(
  26
  27 /*  SYNOPSIS */
  28         const char *path,
  29         char       *buf,
  30         size_t      bufsize)
  31
  32 /*  FUNCTION
  33         Places the contents of a symbolic link in a buffer of given size. No NUL
  34         char is appended to the buffer.
  35
  36     INPUTS
  37         path    - the path to the symbolic link
  38         buf     - pointer to the buffer where to store the symbolic link content
  39         bufsize - the size of the buffer in bytes
  40
  41     RESULT
  42         The call returns the count of characters placed in the buffer if it
  43         succeeds, or a -1 if an error occurs, placing the error code in the
  44         global variable errno.
  45 */
  46 {
  47     ssize_t          res = -1;
  48     struct IOFileSys iofs;
  49     struct DevProc   *dvp = NULL;
  50     LONG             error;
  51     struct Process   *me = (struct Process *)FindTask(NULL);
  52
  53     /* check for empty path before potential conversion from "." to "" */
  54     if (__doupath && path && *path == '\0')
  55     {
  56         errno = ENOENT;
  57         return res;
  58     }
  59
  60     path = __path_u2a(path);
  61     if (path == NULL)
  62         return res;
  63
  64     /* we need to know if it is really a soft link */
  65     InitIOFS(&iofs, FSA_OPEN, DOSBase);
  66     iofs.io_Union.io_OPEN.io_FileMode = FMF_READ;
  67     iofs.io_Union.io_OPEN.io_Filename = StripVolume(path);
  68
  69     do
  70     {
  71         if ((dvp = GetDeviceProc(path, dvp)) == NULL)
  72         {
  73             error = IoErr();
  74             break;
  75         }
  76
  77         error = DoIOFS(&iofs, dvp, NULL, DOSBase);
  78     }
  79     while (error == ERROR_OBJECT_NOT_FOUND);
  80
  81     if (error == ERROR_NO_MORE_ENTRIES)
  82         error = me->pr_Result2 = ERROR_OBJECT_NOT_FOUND;
  83     else if (error == 0)
  84     {
  85         /* open I/O request successful, but this is not*/
  86         /* what we want, don't forget to close again */
  87         InitIOFS(&iofs, FSA_CLOSE, DOSBase);
  88         DoIO((struct IORequest *) &iofs);
  89         /* set an error that translates to EINVAL */
  90         error = me->pr_Result2 = ERROR_OBJECT_WRONG_TYPE;
  91     }
  92     else if (error == ERROR_IS_SOFT_LINK)
  93     {
  94         /* it is a soft link, try to read it */
  95         res = ReadLink(dvp->dvp_Port, dvp->dvp_Lock, path, buf, bufsize);
  96         if (res == -1)
  97             error = IoErr();
  98         else
  99         {
 100             if (res == -2)
 101                 res = bufsize;
 102
 103             /* clear the soft link error */
 104             error = me->pr_Result2 = 0;
 105         }
 106     }
 107
 108     FreeDeviceProc(dvp);
 109
 110     if (error)
 111         errno = IoErr2errno(error);
 112
 113     return res;
 114 }