svn commit: r207304 - in stable/8: sbin/ifconfig share/man/man4 sys/net

[Xin LI]

Author: delphij
Date: Wed Apr 28 00:49:24 2010
New Revision: 207304
URL: http://svn.freebsd.org/changeset/base/207304

Log:
  MFC r206637:
  
  When an underlying ioctl(2) handler returns an error, our ioctl(2)
  interface considers that it hits a fatal error, and will not copyout
  the request structure back for _IOW and _IOWR ioctls, keeping them
  untouched.
  
  The previous implementation of the SIOCGIFDESCR ioctl intends to
  feed the buffer length back to userland.  However, if we return
  an error, the feedback would be defeated and ifconfig(8) would
  trap into an infinite loop.
  
  This commit changes SIOCGIFDESCR to set buffer field to NULL to
  indicate the previous ENAMETOOLONG case.
  
  Reported by:	bschmidt

Modified:
  stable/8/sbin/ifconfig/ifconfig.c
  stable/8/share/man/man4/netintro.4
  stable/8/sys/net/if.c
Directory Properties:
  stable/8/sbin/ifconfig/   (props changed)
  stable/8/share/man/man4/   (props changed)
  stable/8/sys/   (props changed)
  stable/8/sys/amd64/include/xen/   (props changed)
  stable/8/sys/cddl/contrib/opensolaris/   (props changed)
  stable/8/sys/contrib/dev/acpica/   (props changed)
  stable/8/sys/contrib/pf/   (props changed)
  stable/8/sys/dev/xen/xenpci/   (props changed)
  stable/8/sys/geom/sched/   (props changed)

Modified: stable/8/sbin/ifconfig/ifconfig.c
==============================================================================
--- stable/8/sbin/ifconfig/ifconfig.c	Tue Apr 27 23:48:50 2010	(r207303)
+++ stable/8/sbin/ifconfig/ifconfig.c	Wed Apr 28 00:49:24 2010	(r207304)
@@ -906,19 +906,20 @@ status(const struct afswtch *afp, const 
 			ifr.ifr_buffer.buffer = descr;
 			ifr.ifr_buffer.length = descrlen;
 			if (ioctl(s, SIOCGIFDESCR, &ifr) == 0) {
-				if (strlen(descr) > 0)
-					printf("\tdescription: %s\n", descr);
-				break;
-			} else if (errno == ENAMETOOLONG)
-				descrlen = ifr.ifr_buffer.length;
-			else
-				break;
-		} else {
+				if (ifr.ifr_buffer.buffer == descr) {
+					if (strlen(descr) > 0)
+						printf("\tdescription: %s\n",
+						    descr);
+				} else if (ifr.ifr_buffer.length > descrlen) {
+					descrlen = ifr.ifr_buffer.length;
+					continue;
+				}
+			}
+		} else
 			warn("unable to allocate memory for interface"
 			    "description");
-			break;
-		}
-	};
+		break;
+	}
 
 	if (ioctl(s, SIOCGIFCAP, (caddr_t)&ifr) == 0) {
 		if (ifr.ifr_curcap != 0) {

Modified: stable/8/share/man/man4/netintro.4
==============================================================================
--- stable/8/share/man/man4/netintro.4	Tue Apr 27 23:48:50 2010	(r207303)
+++ stable/8/share/man/man4/netintro.4	Wed Apr 28 00:49:24 2010	(r207304)
@@ -32,7 +32,7 @@
 .\"     @(#)netintro.4	8.2 (Berkeley) 11/30/93
 .\" $FreeBSD$
 .\"
-.Dd January 26, 2010
+.Dd April 14, 2010
 .Dt NETINTRO 4
 .Os
 .Sh NAME
@@ -292,8 +292,11 @@ field of
 struct passed in as parameter, and the length would include
 the terminating nul character.
 If there is not enough space to hold the interface length,
-no copy would be done and an
-error would be returned.
+no copy would be done and the
+.Va buffer
+field of
+.Va ifru_buffer
+would be set to NULL.
 The kernel will store the buffer length in the
 .Va length
 field upon return, regardless whether the buffer itself is

Modified: stable/8/sys/net/if.c
==============================================================================
--- stable/8/sys/net/if.c	Tue Apr 27 23:48:50 2010	(r207303)
+++ stable/8/sys/net/if.c	Wed Apr 28 00:49:24 2010	(r207304)
@@ -2115,14 +2115,13 @@ ifhwioctl(u_long cmd, struct ifnet *ifp,
 	case SIOCGIFDESCR:
 		error = 0;
 		sx_slock(&ifdescr_sx);
-		if (ifp->if_description == NULL) {
-			ifr->ifr_buffer.length = 0;
+		if (ifp->if_description == NULL)
 			error = ENOMSG;
-		} else {
+		else {
 			/* space for terminating nul */
 			descrlen = strlen(ifp->if_description) + 1;
 			if (ifr->ifr_buffer.length < descrlen)
-				error = ENAMETOOLONG;
+				ifr->ifr_buffer.buffer = NULL;
 			else
 				error = copyout(ifp->if_description,
 				    ifr->ifr_buffer.buffer, descrlen);