Hi Arturo,
On Fri, May 09, 2014 at 06:45:47PM +0200, Arturo Borrero Gonzalez wrote:
> When _snprintf() reports it would print n characters, that n doesn't include
> the trailing \0 that snprintf adds.
>
> Thus, we need to [re]allocate n+1 characters.
>
> While at it, change the reallocation trigger. If the length of the buffer we
> used is equals to the expanded string length, the output has been truncated.
> In other words, if ret == bufsiz, then the trailing \0 is missing.
>
> Signed-off-by: Arturo Borrero Gonzalez <arturo.borrero.glez@xxxxxxxxx>
> ---
> src/utils.c | 7 ++++---
> 1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/src/utils.c b/src/utils.c
> index 18917f5..b8094aa 100644
> --- a/src/utils.c
> +++ b/src/utils.c
> @@ -195,12 +195,13 @@ int nft_fprintf(FILE *fp, void *obj, uint32_t type, uint32_t flags,
> int ret;
>
> ret = snprintf_cb(buf, bufsiz, obj, type, flags);
I think we should also check here if snprintf returns -1 now that you
have fixed the SNPRINTF_ macro.
> - if (ret > NFT_SNPRINTF_BUFSIZ) {
> - buf = calloc(1, ret);
> + if (ret >= NFT_SNPRINTF_BUFSIZ) {
> + bufsiz = ret + 1;
> +
> + buf = calloc(1, bufsiz);
You can use malloc instead. Just make sure that the string is always
nul-terminated before printing, something like:
bufsiz = ret + 1;
buf = malloc(1, bufsiz);
if (buf == NULL)
return -1;
ret = snprintf(...
if (ret < 0)
...
}
buf[ret] = '\0';
... = fprintf(...
Thanks.
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