Re: [PATCH] error.c: fix gcc warning (vasprintf)

On Tue, Feb 27, 2007 at 10:43:13PM +0200, Kalle Olavi Niemitalo wrote:
> Alexey Tourbin <[email protected]> writes:
> 
> >  	va_start(params, fmt);
> > -	vasprintf((char **) &buf, fmt, params);
> > +	rv = vasprintf((char **) &buf, fmt, params);
> > +	if (rv < 0) {
> > +		perror("vasprintf");
> > +		return;
> > +	}
> >  	va_end(params);
> >  	elinks_internal("assertion failed: %s", buf);
> 
> This is wrong.  va_end and elinks_internal must be called even if
> vasprintf fails.
> 
> Possibilities to be handled:
> (a) vasprintf returns an error and doesn't alter buf.  Because
>     buf is initialized as NULL, this is the same as (b).
> (b) vasprintf returns an error and sets buf = NULL.  This NULL
>     should not be passed to elinks_internal because it will go
>     to snprintf from there and perhaps cause a crash.  The NULL
>     could be replaced with an empty string.  Displaying the
>     error from vasprintf may be useful but may also distract
>     users into reporting that error instead of the file name and
>     line number.
> (c) vasprintf returns an error but sets buf != NULL.  In this
>     case the string probably contains something sensible so it
>     should be used.
> (d) vasprintf returns success but sets buf = NULL.  That should
>     not be possible.
> (e) vasprintf returns success and sets buf != NULL.  This is the
>     usual case.

commit 021a1d43da2db001436d777eeb2f533f011aa471
Author: Alexey Tourbin <[email protected]>
Date:   Sun Oct 15 17:42:31 2006 +0400

    error.c: fix gcc warning (vasprintf)
    (cherry picked from commit 55dff3d9c23e2c8f3358fa265fc4276616713ed5)
    
    Actually if vasprintf fails, use plain fmt string.

diff --git a/src/util/error.c b/src/util/error.c
index 34e4c88..ba6b0ee 100644
--- a/src/util/error.c
+++ b/src/util/error.c
@@ -145,13 +145,16 @@ void
 elinks_assertm(int x, unsigned char *fmt, ...)
 {
 	unsigned char *buf = NULL;
+	int rv;
 	va_list params;
 
 	if (assert_failed) return;
 	if (!(assert_failed = !x)) return;
 
 	va_start(params, fmt);
-	vasprintf((char **) &buf, fmt, params);
+	rv = vasprintf((char **) &buf, fmt, params);
+	if (rv < 0)
+		buf = fmt;
 	va_end(params);
 	elinks_internal("assertion failed: %s", buf);
 	if (buf) free(buf);

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