[Differential] [Request, 22 lines] D2690: In ypbind, eliminate error: dereferencing type-punned pointer will break strict-aliasing rules

[rodrigc (Craig Rodrigues)]

rodrigc created this revision.
rodrigc added reviewers: araujo, bapt, emaste, dim.
rodrigc added a subscriber: freebsd-toolchain.
rodrigc set the repository for this revision to rS FreeBSD src repository.
Herald added a subscriber: imp.

REVISION SUMMARY
  Without this fix, compiling ypbind with gcc 4.9 will give warnings such as this:
  
  ```
  /opt2/branches/head/usr.sbin/ypbind/ypbind.c: In function 'rpc_received':
  /opt2/branches/head/usr.sbin/ypbind/ypbind.c:948:2: warning: dereferencing type-punned pointer will break strict-aliasing rules [-Wstrict-aliasing]
    *(u_int32_t *)&ybr.ypbind_resp_u.ypbind_bindinfo.ypbind_binding_addr = raddrp->sin_addr.s_addr;
    ^
  ```

REPOSITORY
  rS FreeBSD src repository

REVISION DETAIL
  https://reviews.freebsd.org/D2690

AFFECTED FILES
  usr.sbin/ypbind/ypbind.c

CHANGE DETAILS
  diff --git a/usr.sbin/ypbind/ypbind.c b/usr.sbin/ypbind/ypbind.c
  --- a/usr.sbin/ypbind/ypbind.c
  +++ b/usr.sbin/ypbind/ypbind.c
  @@ -225,10 +225,10 @@
   
   	res.ypbind_status = YPBIND_SUCC_VAL;
   	res.ypbind_resp_u.ypbind_error = 0; /* Success */
  -	*(u_int32_t *)&res.ypbind_resp_u.ypbind_bindinfo.ypbind_binding_addr =
  -		ypdb->dom_server_addr.sin_addr.s_addr;
  -	*(u_short *)&res.ypbind_resp_u.ypbind_bindinfo.ypbind_binding_port =
  -		ypdb->dom_server_addr.sin_port;
  +	memcpy(&res.ypbind_resp_u.ypbind_bindinfo.ypbind_binding_addr,
  +	    &ypdb->dom_server_addr.sin_addr.s_addr, sizeof(u_int32_t));
  +	memcpy(&res.ypbind_resp_u.ypbind_bindinfo.ypbind_binding_port,
  +	    &ypdb->dom_server_addr.sin_port, sizeof(u_short));
   	/*printf("domain %s at %s/%d\n", ypdb->dom_domain,
   		inet_ntoa(ypdb->dom_server_addr.sin_addr),
   		ntohs(ypdb->dom_server_addr.sin_port));*/
  @@ -275,8 +275,12 @@
   
   	bzero(&bindsin, sizeof bindsin);
   	bindsin.sin_family = AF_INET;
  -	bindsin.sin_addr.s_addr = *(u_int32_t *)argp->ypsetdom_binding.ypbind_binding_addr;
  -	bindsin.sin_port = *(u_short *)argp->ypsetdom_binding.ypbind_binding_port;
  +	memcpy(&bindsin.sin_addr.s_addr,
  +	    &argp->ypsetdom_binding.ypbind_binding_addr,
  +	    sizeof(u_int32_t));
  +	memcpy(&bindsin.sin_port,
  +	    &argp->ypsetdom_binding.ypbind_binding_port,
  +	    sizeof(u_short));
   	rpc_received(argp->ypsetdom_domain, &bindsin, 1);
   
   	return((void *) &result);
  @@ -945,8 +949,10 @@
   
   	bzero(&ybr, sizeof ybr);
   	ybr.ypbind_status = YPBIND_SUCC_VAL;
  -	*(u_int32_t *)&ybr.ypbind_resp_u.ypbind_bindinfo.ypbind_binding_addr = raddrp->sin_addr.s_addr;
  -	*(u_short *)&ybr.ypbind_resp_u.ypbind_bindinfo.ypbind_binding_port = raddrp->sin_port;
  +	memcpy(ybr.ypbind_resp_u.ypbind_bindinfo.ypbind_binding_addr,
  +	    &raddrp->sin_addr.s_addr, sizeof(u_int32_t));
  +	memcpy(&ybr.ypbind_resp_u.ypbind_bindinfo.ypbind_binding_port,
  +	    &raddrp->sin_port, sizeof(u_short));
   
   	if (writev(ypdb->dom_lockfd, iov, 2) != iov[0].iov_len + iov[1].iov_len) {
   		syslog(LOG_WARNING, "write: %m");

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To: rodrigc, araujo, bapt, emaste, dim
Cc: imp, freebsd-toolchain
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