svn commit: r192464 - user/kmacy/releng_7_2_fcs/sys/kern

[Kip Macy]

Author: kmacy
Date: Wed May 20 19:19:41 2009
New Revision: 192464
URL: http://svn.freebsd.org/changeset/base/192464

Log:
  merge 192144
  Revert r192094. The revision caused problems for sysctl(3) consumers
  that expect that oldlen is filled with required buffer length even when
  supplied buffer is too short and returned error is ENOMEM.
  
  Redo the fix for kern.proc.filedesc, by reverting the req->oldidx when
  remaining buffer space is too short for the current kinfo_file structure.
  Also, only ignore ENOMEM. We have to convert ENOMEM to no error condition
  to keep existing interface for the sysctl, though.
  
  Reported by:	ed, Florian Smeets <flo kasimir com>
  Tested by:	pho

Modified:
  user/kmacy/releng_7_2_fcs/sys/kern/kern_descrip.c

Modified: user/kmacy/releng_7_2_fcs/sys/kern/kern_descrip.c
==============================================================================
--- user/kmacy/releng_7_2_fcs/sys/kern/kern_descrip.c	Wed May 20 18:58:07 2009	(r192463)
+++ user/kmacy/releng_7_2_fcs/sys/kern/kern_descrip.c	Wed May 20 19:19:41 2009	(r192464)
@@ -2872,6 +2872,7 @@ sysctl_kern_proc_filedesc(SYSCTL_HANDLER
 	struct file *fp;
 	struct proc *p;
 	int vfslocked;
+	size_t oldidx;
 
 	name = (int *)arg1;
 	if ((p = pfind((pid_t)name[0])) == NULL)
@@ -3036,14 +3037,26 @@ sysctl_kern_proc_filedesc(SYSCTL_HANDLER
 		    strlen(kif->kf_path) + 1;
 		kif->kf_structsize = roundup(kif->kf_structsize,
 		    sizeof(uint64_t));
+		oldidx = req->oldidx;
 		error = SYSCTL_OUT(req, kif, kif->kf_structsize);
-		if (error)
+		if (error) {
+			if (error == ENOMEM) {
+				/*
+				 * The hack to keep the ABI of sysctl
+				 * kern.proc.filedesc intact, but not
+				 * to account a partially copied
+				 * kinfo_file into the oldidx.
+				 */
+				req->oldidx = oldidx;
+				error = 0;
+			}
 			break;
+		}
 	}
 	FILEDESC_SUNLOCK(fdp);
 	fddrop(fdp);
 	free(kif, M_TEMP);
-	return (0);
+	return (error);
 }
 
 static SYSCTL_NODE(_kern_proc, KERN_PROC_FILEDESC, filedesc, CTLFLAG_RD,