[patch, libgfortran] PR30005 Open errors (not/already exists etc.): show also the file name

[Jerry DeLisle <jvdelisle at verizon dot net>]

:ADDPATCH fortran:

Hi All,

This straight forward patch provides easier to understand error messages on file 
open and includes the file path in the message so users will have a clue where 
to look.

This is an enhancement and therefore should only go to trunk.

Regression tested on x86-64-linux.

I will work up a suitable test case.

If I hear no comments from anyone in the next few days, I will commit.

OK for trunk.

Jerry

2006-12-03  Jerry DeLisle  <jvdelisle@gcc.gnu.org>

	PR libfortran/30005
	* io/open.c: Add errno.h include.
	(new_unit): Add new error messages with file name for file open.

Index: open.c
===================================================================
*** open.c	(revision 119453)
--- open.c	(working copy)
*************** Boston, MA 02110-1301, USA.  */
*** 32,37 ****
--- 32,38 ----
  #include <unistd.h>
  #include <stdio.h>
  #include <string.h>
+ #include <errno.h>
  #include "libgfortran.h"
  #include "io.h"
  
*************** new_unit (st_parameter_open *opp, gfc_un
*** 374,380 ****
    s = open_external (opp, flags);
    if (s == NULL)
      {
!       generate_error (&opp->common, ERROR_OS, NULL);
        goto cleanup;
      }
  
--- 375,411 ----
    s = open_external (opp, flags);
    if (s == NULL)
      {
!       char *path, *msg;
!       path = (char *) gfc_alloca (opp->file_len + 1);
!       msg = (char *) gfc_alloca (opp->file_len + 51);
!       unpack_filename (path, opp->file, opp->file_len);
! 
!       switch (errno)
! 	{
! 	case ENOENT: 
! 	  st_sprintf (msg, "File '%s' does not exist", path);
! 	  generate_error (&opp->common, ERROR_OS, msg);
! 	  break;
! 
! 	case EEXIST:
! 	  st_sprintf (msg, "File '%s' already exists", path);
! 	  generate_error (&opp->common, ERROR_OS, msg);
! 	  break;
! 
! 	case EACCES:
! 	  st_sprintf (msg, "Permission denied trying to open file '%s'", path);
! 	  generate_error (&opp->common, ERROR_OS, msg);
! 	  break;
! 
! 	case EISDIR:
! 	  st_sprintf (msg, "'%s' is a directory", path);
! 	  generate_error (&opp->common, ERROR_OS, msg);
! 	  break;
! 
! 	default:
! 	  generate_error (&opp->common, ERROR_OS, NULL);
! 	}
! 
        goto cleanup;
      }