[src/trunk]: src/lib/libkvm Keep /dev/ksyms open in _kvm_open(). This way /de...

[maxv <maxv%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/191592a49793
branches:  trunk
changeset: 359347:191592a49793
user:      maxv <maxv%NetBSD.org@localhost>
date:      Wed Feb 07 14:03:18 2018 +0000

description:
Keep /dev/ksyms open in _kvm_open(). This way /dev/ksyms can be put into
$g_kmem without breaking the tools that need kmem+ksyms.

Discussed on tech-kern@ three weeks ago. The original issue was reported
by maya@, the patch was written by Tom Ivar Helbekkmo, ok christos@.

diffstat:

 lib/libkvm/kvm.c |  34 ++++------------------------------
 1 files changed, 4 insertions(+), 30 deletions(-)

diffs (70 lines):

diff -r 166fc55f2690 -r 191592a49793 lib/libkvm/kvm.c
--- a/lib/libkvm/kvm.c  Wed Feb 07 13:22:41 2018 +0000
+++ b/lib/libkvm/kvm.c  Wed Feb 07 14:03:18 2018 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: kvm.c,v 1.102 2016/03/29 06:51:40 mrg Exp $    */
+/*     $NetBSD: kvm.c,v 1.103 2018/02/07 14:03:18 maxv Exp $   */
 
 /*-
  * Copyright (c) 1989, 1992, 1993
@@ -38,7 +38,7 @@
 #if 0
 static char sccsid[] = "@(#)kvm.c      8.2 (Berkeley) 2/13/94";
 #else
-__RCSID("$NetBSD: kvm.c,v 1.102 2016/03/29 06:51:40 mrg Exp $");
+__RCSID("$NetBSD: kvm.c,v 1.103 2018/02/07 14:03:18 maxv Exp $");
 #endif
 #endif /* LIBC_SCCS and not lint */
 
@@ -322,15 +322,6 @@
                strlcpy(kd->kernelname, uf, sizeof(kd->kernelname));
        } else {
                strlcpy(kd->kernelname, _PATH_KSYMS, sizeof(kd->kernelname));
-               /*
-                * We're here because /dev/ksyms was opened
-                * successfully.  However, we don't want to keep it
-                * open, so we close it now.  Later, we will open
-                * it again, since it will be the only case where
-                * kd->nlfd is negative.
-                */
-               close(kd->nlfd);
-               kd->nlfd = -1;
        }
 
        if ((kd->pmfd = open(mf, flag | O_CLOEXEC, 0)) < 0) {
@@ -769,33 +760,16 @@
 int
 kvm_nlist(kvm_t *kd, struct nlist *nl)
 {
-       int rv, nlfd;
-
-       /*
-        * kd->nlfd might be negative when we get here, and in that
-        * case that means that we're using /dev/ksyms.
-        * So open it again, just for the time we retrieve the list.
-        */
-       if (kd->nlfd < 0) {
-               nlfd = open(_PATH_KSYMS, O_RDONLY | O_CLOEXEC, 0);
-               if (nlfd < 0) {
-                       _kvm_err(kd, 0, "failed to open %s", _PATH_KSYMS);
-                       return (nlfd);
-               }
-       } else
-               nlfd = kd->nlfd;
+       int rv;
 
        /*
         * Call the nlist(3) routines to retrieve the given namelist.
         */
-       rv = __fdnlist(nlfd, nl);
+       rv = __fdnlist(kd->nlfd, nl);
 
        if (rv == -1)
                _kvm_err(kd, 0, "bad namelist");
 
-       if (kd->nlfd < 0)
-               close(nlfd);
-
        return (rv);
 }