asnprintf followup

[Jeff Johnston]

Ok.

-- Jeff J.

Eric Blake wrote:
> May I commit this?  It turns out that GNU code found it useful to call 
> asnprintf with an existing buf not on the heap, but a calculated remaining size 
> of 0; asnprintf dumped core when it tried to realloc the user's buf to make 
> room for the trailing NUL.
> 
> 2007-05-09  Eric Blake  <ebb9@byu.net>
> 
> 	Allow zero size with non-null buf in *asnprintf.
> 	* libc/stdio/asnprintf.c (_asnprintf_r, asnprintf): Avoid free'ing
> 	user's buf.
> 	* libc/stdio/asniprintf.c (_asniprintf_r, asniprintf): Likewise.
> 	* libc/stdio/vasniprintf.c (_vasniprintf_r): Likewise.
> 	* libc/stdio/vasnprintf.c (_vasnprintf_r): Likewise.
> 
> Index: libc/stdio/asniprintf.c
> ===================================================================
> RCS file: /cvs/src/src/newlib/libc/stdio/asniprintf.c,v
> retrieving revision 1.1
> diff -u -r1.1 asniprintf.c
> --- libc/stdio/asniprintf.c	4 May 2007 02:55:16 -0000	1.1
> +++ libc/stdio/asniprintf.c	9 May 2007 16:36:23 -0000
> @@ -34,6 +34,7 @@
>        /* mark a zero-length reallocatable buffer */
>        f._flags = __SWR | __SSTR | __SMBF;
>        len = 0;
> +      buf = NULL;
>      }
>    f._bf._base = f._p = (unsigned char *) buf;
>    /* For now, inherit the 32-bit signed limit of FILE._bf._size.
> @@ -80,6 +81,7 @@
>        /* mark a zero-length reallocatable buffer */
>        f._flags = __SWR | __SSTR | __SMBF;
>        len = 0;
> +      buf = NULL;
>      }
>    f._bf._base = f._p = (unsigned char *) buf;
>    /* For now, inherit the 32-bit signed limit of FILE._bf._size.
> Index: libc/stdio/asnprintf.c
> ===================================================================
> RCS file: /cvs/src/src/newlib/libc/stdio/asnprintf.c,v
> retrieving revision 1.1
> diff -u -r1.1 asnprintf.c
> --- libc/stdio/asnprintf.c	4 May 2007 02:55:16 -0000	1.1
> +++ libc/stdio/asnprintf.c	9 May 2007 16:36:23 -0000
> @@ -34,6 +34,7 @@
>        /* mark a zero-length reallocatable buffer */
>        f._flags = __SWR | __SSTR | __SMBF;
>        len = 0;
> +      buf = NULL;
>      }
>    f._bf._base = f._p = (unsigned char *) buf;
>    /* For now, inherit the 32-bit signed limit of FILE._bf._size.
> @@ -80,6 +81,7 @@
>        /* mark a zero-length reallocatable buffer */
>        f._flags = __SWR | __SSTR | __SMBF;
>        len = 0;
> +      buf = NULL;
>      }
>    f._bf._base = f._p = (unsigned char *) buf;
>    /* For now, inherit the 32-bit signed limit of FILE._bf._size.
> Index: libc/stdio/vasniprintf.c
> ===================================================================
> RCS file: /cvs/src/src/newlib/libc/stdio/vasniprintf.c,v
> retrieving revision 1.1
> diff -u -r1.1 vasniprintf.c
> --- libc/stdio/vasniprintf.c	4 May 2007 02:55:16 -0000	1.1
> +++ libc/stdio/vasniprintf.c	9 May 2007 16:36:23 -0000
> @@ -34,6 +34,7 @@
>        /* mark a zero-length reallocatable buffer */
>        f._flags = __SWR | __SSTR | __SMBF;
>        len = 0;
> +      buf = NULL;
>      }
>    f._bf._base = f._p = (unsigned char *) buf;
>    /* For now, inherit the 32-bit signed limit of FILE._bf._size.
> Index: libc/stdio/vasnprintf.c
> ===================================================================
> RCS file: /cvs/src/src/newlib/libc/stdio/vasnprintf.c,v
> retrieving revision 1.1
> diff -u -r1.1 vasnprintf.c
> --- libc/stdio/vasnprintf.c	4 May 2007 02:55:16 -0000	1.1
> +++ libc/stdio/vasnprintf.c	9 May 2007 16:36:23 -0000
> @@ -34,6 +34,7 @@
>        /* mark a zero-length reallocatable buffer */
>        f._flags = __SWR | __SSTR | __SMBF;
>        len = 0;
> +      buf = NULL;
>      }
>    f._bf._base = f._p = (unsigned char *) buf;
>    /* For now, inherit the 32-bit signed limit of FILE._bf._size.
> 
>