Date: Sun, 12 Sep 2004 20:10:48 GMT From: Giorgos Keramidas <keramida@freebsd.org> To: freebsd-bugs@FreeBSD.org Subject: Re: bin/71628: [PATCH] cleanup of the usr.sbin/rpcbind code Message-ID: <200409122010.i8CKAmSf028200@freefall.freebsd.org>
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The following reply was made to PR bin/71628; it has been noted by GNATS.
From: Giorgos Keramidas <keramida@freebsd.org>
To: Dan Lukes <dan@obluda.cz>
Cc: alfred@freebsd.org, bug-followup@freebsd.org
Subject: Re: bin/71628: [PATCH] cleanup of the usr.sbin/rpcbind code
Date: Sun, 12 Sep 2004 22:39:20 +0300
On 2004-09-12 04:38, Dan Lukes <dan@obluda.cz> wrote:
> static int
> init_transport(struct netconfig *nconf)
> {
> - int fd;
> + int fd = fd; /* init to suppres "may be used uninitialized" warning */
Err, no please. GCC complains that fd "may be used uninitialized" because
of this construct near line 275 and the rest of the function body:
275 if (nconf->nc_semantics != NC_TPI_CLTS) {
276 if ((fd = __rpc_nconf2fd(nconf)) < 0) {
277 int non_fatal = 0;
...
283 return (1);
284 }
...
311 if (nconf->nc_semantics == NC_TPI_CLTS) {
...
334 while (nhostsbak > 0) {
...
339 if ((fd = __rpc_nconf2fd(nconf)) < 0) {
...
452 } else {
...
466 if (bind(fd, sa, addrlen) < 0) {
Pay attention to this last line. GCC believes that fd can be used
uninitialized because if NC_TPI_CLTS is not used the bind() call will
receive an uninitialized value of `fd'. I'm not acquainted with the
internals of rpcbind() at all, but I know that Alfred Perlstein is.
He's probably the best person to suggest a fix for this warning, if one
is really needed.
> struct t_bind taddr;
> struct addrinfo hints, *res = NULL;
> struct __rpc_sockinfo si;
> - SVCXPRT *my_xprt;
> ! SVCXPRT *my_xprt = my_xprt; /* init to suppres "may be used uninitialized" warning */
No. I don't know why you think that this is a good fix for all the
uninitialized pointer warnings. It's not. Never :-/
This warning is probably caused by GCC's inability to make sure that when
`bar' is a pointer this construct is perfectly fine:
if (foo) {
...
if (bar = baz())
...
} else {
...
if (bar = baz2())
...
}
if (blah(bar))
...
After a quick glance at the source of rpcbind() I think that there's no way
that my_xrpt can be used uninitialized. A proper fix for this warning
would be then to just set my_xrpt to NULL at first and let the rest of the
function unchanged regarding my_xrpt.
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