On 11/13/14 1:14 PM, Mark Tinguely wrote:
> Linux strcpy() corrupts the output string when the input
Not Linux strcpy in particular; per C99:
> The strcpy function copies the string pointed to by s2
> (including the terminating null character) into the array
> pointed to by s1. If copying takes place between objects
> that overlap, the behavior is undefined.
^^^^^^^^^^^^^^^^^^^^^^^^^
> and output strings overlap. The shrink() function in xfsrestore
> uses an overlapping strcpy() to remove special characters when
> processing an interactive command line. The resultant command
> will fail.
>
> examples:
> -> cd "AOGC exome chip core genotyping"
> AOGC exome chp core genotyping not found
> -> cd "t t"
> tt not found
>
> Fix my manually moving the characters in the array.
>
> Signed-off-by: Mark Tinguely <tinguely@xxxxxxx>
> ---
> restore/tree.c | 14 +++++++++++++-
> 1 file changed, 13 insertions(+), 1 deletion(-)
>
> Index: b/restore/tree.c
> ===================================================================
> --- a/restore/tree.c
> +++ b/restore/tree.c
> @@ -4857,7 +4857,19 @@ distance_to_space( char *s, char *l )
> static void
> shrink( char *s, size_t cnt )
> {
> - strcpy( s, s + cnt );
> + /*
> + * Linux strcpy corrupts the string if the src and dst overlap.
> + * Manually copy the entries to the left.
> + *
> + * Since the liter array is mostly nulls, shrink is not moving
what is the "liter array?" Ah well. Context. ;)
> + * the array left as intended. Does not seem to be many embedded
> + * processing characters, so leaving it for now
> + */
> + char *m = s + cnt;
> + while (*m != '\0')
> + *s++ = *m++;
> + /* NULL the last character of the string */
> + *s = '\0';
> }
Would this be any less manual?
size_t n = strlen(s+cnt) + 1; /* 1 for terminating NULL */
memmove(s, s + cnt, n);
because memmove is ok with overlaps.
-Eric
> static int
>
>
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