[src/trunk]: src/sys/dev Make kernel core dumps on cgd(4) work.

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

details:   https://anonhg.NetBSD.org/src/rev/cb7a83854d63
branches:  trunk
changeset: 346363:cb7a83854d63
user:      riastradh <riastradh%NetBSD.org@localhost>
date:      Sun Jul 10 17:40:23 2016 +0000

description:
Make kernel core dumps on cgd(4) work.

diffstat:

 sys/dev/cgd.c |  53 ++++++++++++++++++++++++++++++++++++++++++++++++++---
 1 files changed, 50 insertions(+), 3 deletions(-)

diffs (88 lines):

diff -r 06b2ae841843 -r cb7a83854d63 sys/dev/cgd.c
--- a/sys/dev/cgd.c     Sun Jul 10 04:44:47 2016 +0000
+++ b/sys/dev/cgd.c     Sun Jul 10 17:40:23 2016 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: cgd.c,v 1.107 2016/07/07 06:55:40 msaitoh Exp $ */
+/* $NetBSD: cgd.c,v 1.108 2016/07/10 17:40:23 riastradh Exp $ */
 
 /*-
  * Copyright (c) 2002 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: cgd.c,v 1.107 2016/07/07 06:55:40 msaitoh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: cgd.c,v 1.108 2016/07/10 17:40:23 riastradh Exp $");
 
 #include <sys/types.h>
 #include <sys/param.h>
@@ -106,6 +106,7 @@
 
 static int     cgd_diskstart(device_t, struct buf *);
 static void    cgdiodone(struct buf *);
+static int     cgd_dumpblocks(device_t, void *, daddr_t, int);
 
 static int     cgd_ioctl_set(struct cgd_softc *, void *, struct lwp *);
 static int     cgd_ioctl_clr(struct cgd_softc *, struct lwp *);
@@ -122,7 +123,7 @@
         .d_strategy = cgdstrategy,
         .d_iosize = NULL,
         .d_diskstart = cgd_diskstart,
-        .d_dumpblocks = NULL,
+        .d_dumpblocks = cgd_dumpblocks,
         .d_lastclose = NULL
 };
 
@@ -494,6 +495,52 @@
        dk_start(dksc, NULL);
 }
 
+static int
+cgd_dumpblocks(device_t dev, void *va, daddr_t blkno, int nblk)
+{
+       struct cgd_softc *sc = device_private(dev);
+       struct dk_softc *dksc = &sc->sc_dksc;
+       struct disk_geom *dg = &dksc->sc_dkdev.dk_geom;
+       size_t nbytes, blksize;
+       void *buf;
+       int error;
+
+       /*
+        * dk_dump gives us units of disklabel sectors.  Everything
+        * else in cgd uses units of diskgeom sectors.  These had
+        * better agree; otherwise we need to figure out how to convert
+        * between them.
+        */
+       KASSERTMSG((dg->dg_secsize == dksc->sc_dkdev.dk_label->d_secsize),
+           "diskgeom secsize %"PRIu32" != disklabel secsize %"PRIu32,
+           dg->dg_secsize, dksc->sc_dkdev.dk_label->d_secsize);
+       blksize = dg->dg_secsize;
+
+       /*
+        * Compute the number of bytes in this request, which dk_dump
+        * has `helpfully' converted to a number of blocks for us.
+        */
+       nbytes = nblk*blksize;
+
+       /* Try to acquire a buffer to store the ciphertext.  */
+       buf = cgd_getdata(dksc, nbytes);
+       if (buf == NULL)
+               /* Out of memory: give up.  */
+               return ENOMEM;
+
+       /* Encrypt the caller's data into the temporary buffer.  */
+       cgd_cipher(sc, buf, va, nbytes, blkno, blksize, CGD_CIPHER_ENCRYPT);
+
+       /* Pass it on to the underlying disk device.  */
+       error = bdev_dump(sc->sc_tdev, blkno, buf, nbytes);
+
+       /* Release the buffer.  */
+       cgd_putdata(dksc, buf);
+
+       /* Return any error from the underlying disk device.  */
+       return error;
+}
+
 /* XXX: we should probably put these into dksubr.c, mostly */
 static int
 cgdread(dev_t dev, struct uio *uio, int flags)