Re: [PATCH] Add compat/vsnprintf.c for systems that returns -1 on maxsize reached

From: Wayne Davison <wayne@opencoder.net>
Date: Mar 5, 2008, 15:54 UTC
Message-ID: <20080305155412.GA19295@herod.dreamhost.com>
In-Reply-To: <200803051600.06605.michal.rokos@nextsoft.cz>

On Wed, Mar 05, 2008 at 04:00:06PM +0100, Michal Rokos wrote:

> +		[[char buf[1];
> +		  if (test_vsnprintf(buf, 1, "%s", "12345") != 5) return 1;
> +		  if (snprintf(buf, 1, "%s", "12345") != 5) return 1]])],

I'd suggest using a longer buf, requesting a longer length (e.g. 3 instead of 1), and then making sure that the resulting buf is right (e.g. "12" instead of "123").

		[[char buf[6];
		  if (test_vsnprintf(buf, 3, "%s", "12345") != 5
		   || strcmp(buf, "12") != 0) return 1;
		  if (snprintf(buf, 3, "%s", "12345") != 5
		   || strcmp(buf, "12") != 0) return 1]])],

Then, set a define that snprintf is bogus and use a version of snprintf() based on this instead:

http://rsync.samba.org/ftp/unpacked/rsync/lib/snprintf.c

That defines rsync_snprintf() and rsync_vsnprintf() functions (which could be renamed for git). Then, in a global .h file, add something like this:

#if !defined HAVE_VSNPRINTF || !defined HAVE_C99_VSNPRINTF #define vsnprintf rsync_vsnprintf int vsnprintf(char *str, size_t count, const char *fmt, va_list args); #endif

#if !defined HAVE_SNPRINTF || !defined HAVE_C99_VSNPRINTF #define snprintf rsync_snprintf int snprintf(char *str, size_t count, const char *fmt,...); #endif

Just be sure to put those that after the various system includes so that they are not adversely affected.

..wayne..