Problem report #7

Problem report #7

[Dan Nicolaescu]

CID: 7
Checker: DEADCODE (help)
File: emacs/src/fileio.c
Function: Finsert_file_contents
Description: After this line, the value of "fd" is equal to -1

Event assignment: Assigning "-1" to "fd"
Event const: After this line, the value of "fd" is equal to -1
Also see events: [dead_error_line][dead_error_condition][const]

3799 	  fd = -1;
3800 	
3801 	#ifdef WINDOWSNT
3802 	  {
3803 	    Lisp_Object tem = Vw32_get_true_file_attributes;
3804 	
3805 	    /* Tell stat to use expensive method to get accurate info.  */
3806 	    Vw32_get_true_file_attributes = Qt;
3807 	    total = stat (SDATA (filename), &st);
3808 	    Vw32_get_true_file_attributes = tem;
3809 	  }
3810 	  if (total < 0)
3811 	#else
3812 	#ifndef APOLLO
3813 	  if (stat (SDATA (filename), &st) < 0)
3814 	#else
3815 	  if ((fd = emacs_open (SDATA (filename), O_RDONLY, 0)) < 0
3816 	      || fstat (fd, &st) < 0)
3817 	#endif /* not APOLLO */
3818 	#endif /* WINDOWSNT */
3819 	    {

Event dead_error_line: Cannot reach this line of code
Event dead_error_condition: On this path, the condition "fd >= 0" could not be true
Also see events: [dead_error_condition][assignment][const]

3820 	      if (fd >= 0) emacs_close (fd);
3821 	    badopen:
3822 	      if (NILP (visit))
3823 		report_file_error ("Opening input file", Fcons (orig_filename, Qnil));
3824 	      st.st_mtime = -1;
3825 	      how_much = 0;
3826 	      if (!NILP (Vcoding_system_for_read))
3827 		Fset (Qbuffer_file_coding_system, Vcoding_system_for_read);
3828 	      goto notfound;
3829 	    }

Re: Problem report #7

[Stuart D. Herring]

> 3815 	  if ((fd = emacs_open (SDATA (filename), O_RDONLY, 0)) < 0
> 3816 	      || fstat (fd, &st) < 0)
> 3817 	#endif /* not APOLLO */
> 3818 	#endif /* WINDOWSNT */

This code can certainly assign interesting values to fd.

> 3819 	    {
>
> Event dead_error_line: Cannot reach this line of code
> Event dead_error_condition: On this path, the condition "fd >= 0" could
> not be true
> Also see events: [dead_error_condition][assignment][const]
>
> 3820 	      if (fd >= 0) emacs_close (fd);

So this test isn't useless.  But maybe this line should be moved to just
under the emacs_open() call, since it's only useful there?  This fails to
imply any dangerous bug, in any event.

Davis

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Re: Problem report #7

[Andreas Schwab]

Dan Nicolaescu <dann@ics.uci.edu> writes:

> 3812 	#ifndef APOLLO
> 3813 	  if (stat (SDATA (filename), &st) < 0)
> 3814 	#else
> 3815 	  if ((fd = emacs_open (SDATA (filename), O_RDONLY, 0)) < 0
> 3816 	      || fstat (fd, &st) < 0)
> 3817 	#endif /* not APOLLO */
> 3818 	#endif /* WINDOWSNT */
> 3819 	    {
>
> Event dead_error_line: Cannot reach this line of code
> Event dead_error_condition: On this path, the condition "fd >= 0" could not be true

Unless APOLLO is defined.

Andreas.

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