kern/78664: truss does not work on 5-STABLE(5.4-PRERELEASE)

[Dan Nelson]

The following reply was made to PR kern/78664; it has been noted by GNATS.

From: Dan Nelson <dnelson at allantgroup.com>
To: freebsd-gnats-submit at FreeBSD.org, hashiz at tomba.cskk-sv.co.jp,
	jeffr at FreeBSD.org
Cc:  
Subject: Re: kern/78664: truss does not work on 5-STABLE(5.4-PRERELEASE)
Date: Fri, 18 Mar 2005 13:08:01 -0600

 In the last episode (Mar 17), Dan Nelson said:
 > HASHI Hiroaki wrote:
 > > truss command does not work with below message.
 > >
 > > "truss: PIOCBIS: Inappropriate ioctl for device"
 > 
 > I've narrowed it down to something committed between 02-24 and 02-27,
 > but can't continue the binary search until tonight.  It would be
 > really nice if this was fixed before 5.4 gets released :)
 
 Jeff, it looks like your fdesc-locking MFC inadvertantly broke the
 PIOCBIS ioctl.  Craig Rodrigues' analysis at
 http://lists.freebsd.org/pipermail/freebsd-current/2004-November/043647.html
 looks accurate: the extra argument checking in
 kern/sys_generic.c:ioctl() is failing on a 0-byte IOC_IN ioctl that
 really should have used _IO().
 
 A quick grep shows some misuse in the other direction.  All the ioctls
 in aac_ioctl.h are _IO(), but many take struct* arguments and should
 have been _IOR or _IOW.  Since the ioctl definition itself is
 consistent though, it would still pass the checks.  I didn't see any
 ioctls (besides the pioctl.h ones) that would fail the checks, but
 since you can't guarantee that 3rd-party drivers aren't doing the same
 thing with private ioctls of their own, I think removing the size
 checks completely (maybe sending a kernel printf saying "this will fail
 on 6.x" on first occurance or something) is the best solution.
 
 Index: sys_generic.c
 ===================================================================
 RCS file: /home/ncvs/src/sys/kern/sys_generic.c,v
 retrieving revision 1.132.2.3
 diff -u -r1.132.2.3 sys_generic.c
 --- sys_generic.c	27 Feb 2005 02:42:55 -0000	1.132.2.3
 +++ sys_generic.c	18 Mar 2005 18:32:53 -0000
 @@ -500,9 +503,7 @@
  	 */
  	size = IOCPARM_LEN(com);
  	if ((size > IOCPARM_MAX) ||
 -	    ((com & (IOC_VOID  | IOC_IN | IOC_OUT)) == 0) ||
 -	    ((com & IOC_VOID) && size > 0) ||
 -	    ((com & (IOC_IN | IOC_OUT)) && size == 0)) {
 +	    ((com & (IOC_VOID | IOC_IN | IOC_OUT)) == 0)) {
  		fdrop(fp, td);
  		return (ENOTTY);
  	}
 
 
 -- 
 	Dan Nelson
 	dnelson at allantgroup.com