Re: [1/6] try 2: msvcrt: Implement strcpy_s

[Detlef Riekenberg]

On Do, 2007-11-15 at 17:35 +0100, Stefan Dösinger wrote:
> +    memset(dest, 'X', sizeof(dest));
> +    ret = pstrcpy_s(dest, sizeof(dest), small);
> +    ok(ret == 0, "Copying a string into a big enough destination
> returned %d, expected 0\n", ret);
> +    ok(dest[0] == 's' && dest[1] == 'm' && dest[2] == 'a' && dest[3]
> == 'l' &&
> +       dest[4] == 'l' && dest[5] == '\0'&& dest[6] == 'X' && dest[7]
> == 'X',

Is it really needed to check the memory after the end of the string?
Does an application depend on this?

--- cut ---
  memset(dest, 'X', sizeof(dest)-1);
  /* never read past the buffer, when we check the result */
  dest[sizeof(dest)-1] = '\0';

  ret = pstrcpy_s(dest, sizeof(dest), small);
  ok( !ret && !lstrcmpA(dest, small), 
      "got %d and '%s' (expected '0' and '%s')\n", ret, dest, small);

-- cut --


For my tests with buffers, i found it useful to test with:
- buffer present, but size is 0
- buffer one byte smaller as the string (no space left for the '\0')
- buffer large enough for the string, but no space left for the '\0' 
- buffer exact as needed
- buffer one byte larger as needed
- empty source string
- NULL source
- NULL target

This allow you to verify, how the terminating '\0' is handled.

Did you test with invalid pointers (crash / handled graceful)?


-- 
 
By by ... Detlef

[1/6] try 2: msvcrt: Implement strcpy_s

[Stefan Dösinger]

Am Freitag, 16. November 2007 00:45:47 schrieb Detlef Riekenberg:
> On Do, 2007-11-15 at 17:35 +0100, Stefan Dösinger wrote:
> > +    memset(dest, 'X', sizeof(dest));
> > +    ret = pstrcpy_s(dest, sizeof(dest), small);
> > +    ok(ret == 0, "Copying a string into a big enough destination
> > returned %d, expected 0\n", ret);
> > +    ok(dest[0] == 's' && dest[1] == 'm' && dest[2] == 'a' && dest[3]
> > == 'l' &&
> > +       dest[4] == 'l' && dest[5] == '\0'&& dest[6] == 'X' && dest[7]
> > == 'X',
>
> Is it really needed to check the memory after the end of the string?
> Does an application depend on this?
> It shows that the msdn documents the function incorrectly: It says the string 
> is unmodified, which is apparently not the case.
> Did you test with invalid pointers (crash / handled graceful)?
> No, good idea, I'll try that now

[1/6] try 2: msvcrt: Implement strcpy_s

[Stefan Dösinger]

Am Freitag, 16. November 2007 11:25:39 schrieb Stefan Dösinger:
> > Did you test with invalid pointers (crash / handled graceful)?
>
> No, good idea, I'll try that now
> This crashes