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Re: [PATCH 2/3] libio: Update tst-fmemopen2.c
- From: Rasmus Villemoes <rv at rasmusvillemoes dot dk>
- To: Adhemerval Zanella <azanella at linux dot vnet dot ibm dot com>
- Cc: "GNU C. Library" <libc-alpha at sourceware dot org>
- Date: Mon, 23 Jun 2014 20:39:10 +0200
- Subject: Re: [PATCH 2/3] libio: Update tst-fmemopen2.c
- Authentication-results: sourceware.org; auth=none
- References: <53A82999 dot 3040108 at linux dot vnet dot ibm dot com>
Adhemerval Zanella <azanella@linux.vnet.ibm.com> writes:
> This patch updates tst-fmemopen2 to check for fmemopen with NULL buffer
> inputs and also refactor the code a bit.
>
> --
>
> * stdio-common/tst-fmemopen2.c (do_test): Add test for NULL and zero
> length buffers.
>
> ---
>
> diff --git a/stdio-common/tst-fmemopen2.c b/stdio-common/tst-fmemopen2.c
> index c2a4baa..652c412 100644
> --- a/stdio-common/tst-fmemopen2.c
> +++ b/stdio-common/tst-fmemopen2.c
[snip]
> +}
> +
> +static int
> +do_test_length_zero (void)
> +{
> + int result = 0;
> + FILE *fp;
> + char buf[] = "";
> + const size_t nbuf = 0;
> + int r;
> +
> + fp = fmemopen (buf, nbuf, "r");
> + if (fp == NULL)
> + {
> + printf ("%s: fmemopen failed\n", __FUNCTION__);
> + return 1;
> + }
> +
> + /* Reading any data on a zero-length buffer should return EOF */
Missing full stop.
> + if ((r = fgetc (fp)) != EOF)
> + {
> + printf ("%s: fgetc on a zero-lenght returned: %d\n",
s/lenght/length/
>
> + __FUNCTION__, r);
> + result = 1;
> + }
> + off_t o = ftello (fp);
> + if (o != 0)
> + {
> + printf ("%s: first ftello returned %ld, expected 0\n",
> + __FUNCTION__, o);
> + result = 1;
> + }
> + fclose (fp);
> +
> + /* Writing any data shall start at current position and shall not pass
> + current buffer size beyond the size in fmemopen call. */
> + fp = fmemopen (buf, nbuf, "w");
> + if (fp == NULL)
> + {
> + printf ("%s: second fmemopen failed\n", __FUNCTION__);
> + return 1;
> + }
> +
> + static const char str[] = "hello world";
> + /* Because of buffering, fputs call itself don't fail, however the final
> + buffer should be not changed because of lenght 0 passed in fmemopen
s/lenght/length/
> + call. */
> + fputs (str, fp);
I think it would be useful to do an fflush(fp) and check that the error
flag is set, and perhaps also to check that errno is set to ENOSPC.
> + fclose (fp);
> +
> + if (strcmp (buf, "") != 0)
> + {
> + printf ("%s: strcmp (%s, "") failed\n", __FUNCTION__, buf);
> + return 1;
> + }
> +
Maybe it would be a bit more robust if buf was declared with a somewhat
larger size than the 1 implied from its initialization with "", so that
if the write test fails, adjacent stack variables are not necessarily
overwritten.
Rasmus
PS: Thanks for allowing len==0 :-)