[src/trunk]: src/sys/arch/macppc/macppc Add support for BSD disklabels, scann...

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

details:   https://anonhg.NetBSD.org/src/rev/79cce7806405
branches:  trunk
changeset: 773004:79cce7806405
user:      hauke <hauke%NetBSD.org@localhost>
date:      Tue Jan 24 15:24:55 2012 +0000

description:
Add support for BSD disklabels, scanning the beginning of the disk
in four-byte strides, like disklabel(8) does it.

Since the netbsd-6 branch is around the corner, this is a
minimally-intrusive addition.

Note there is no write support, for good reasons.
Note also that disksubr.c is in dire need of re-structuring.

diffstat:

 sys/arch/macppc/macppc/disksubr.c |  83 +++++++++++++++++++++++++++++++++++++-
 1 files changed, 79 insertions(+), 4 deletions(-)

diffs (118 lines):

diff -r e40f90330550 -r 79cce7806405 sys/arch/macppc/macppc/disksubr.c
--- a/sys/arch/macppc/macppc/disksubr.c Tue Jan 24 09:57:40 2012 +0000
+++ b/sys/arch/macppc/macppc/disksubr.c Tue Jan 24 15:24:55 2012 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: disksubr.c,v 1.47 2009/03/16 23:11:12 dsl Exp $        */
+/*     $NetBSD: disksubr.c,v 1.48 2012/01/24 15:24:55 hauke Exp $      */
 
 /*
  * Copyright (c) 1982, 1986, 1988 Regents of the University of California.
@@ -106,7 +106,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: disksubr.c,v 1.47 2009/03/16 23:11:12 dsl Exp $");
+__KERNEL_RCSID(0, "$NetBSD: disksubr.c,v 1.48 2012/01/24 15:24:55 hauke Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -137,6 +137,8 @@
                struct disklabel *, struct cpu_disklabel *);
 static const char *read_dos_label(dev_t, void (*)(struct buf *),
                struct disklabel *, struct cpu_disklabel *);
+static const char *read_bsd_label(dev_t, void (*)(struct buf *),
+               struct disklabel *, struct cpu_disklabel *);
 static int get_netbsd_label(dev_t, void (*)(struct buf *),
                struct disklabel *, struct cpu_disklabel *);
 
@@ -387,6 +389,78 @@
        return msg;
 }
 
+/*
+ * Scan the disk buffer in four byte strides for a native BSD
+ * disklabel (different ports have variably-sized bootcode before
+ * the label)
+ */
+static const char *
+read_bsd_label(dev_t dev, void (*strat)(struct buf *), struct disklabel *lp,
+    struct cpu_disklabel *osdep)
+{
+       struct disklabel *dlp;
+       struct buf *bp;
+       const char *msg;
+       struct disklabel *blk_start, *blk_end;
+       int size, match;
+       
+       msg = NULL;
+
+       /* 
+        * Read in the first #(NUM_PARTS + 1) blocks of the disk.
+        * The native Macintosh partition table starts at 
+        * sector #1, but we want #0 too for the BSD label.
+        */
+       size = roundup((NUM_PARTS + 1) << DEV_BSHIFT, lp->d_secsize);
+       bp = geteblk(size);
+
+       bp->b_dev = dev;
+       bp->b_blkno = 0;
+       bp->b_resid = 0;
+       bp->b_bcount = size;
+       bp->b_flags |= B_READ;
+       bp->b_cylinder = 1 / lp->d_secpercyl;
+       (*strat)(bp);
+
+       match = 0;
+       
+       if (biowait(bp)) {
+               msg = "I/O error reading BSD disklabel";
+       } else {
+               /*
+                * Hunt the label, starting at the beginning of the disk.
+                * When we find an inconsistent label, report and continue.
+                */
+               blk_start = (struct disklabel *)bp->b_data;
+               blk_end = (struct disklabel *)((char *)bp->b_data +
+                   (NUM_PARTS << DEV_BSHIFT) - sizeof(struct disklabel));
+
+               for (dlp = blk_start; dlp <= blk_end; 
+                    dlp = (struct disklabel *)((char *)dlp + sizeof(long))) {
+                       if (dlp->d_magic == DISKMAGIC &&
+                           dlp->d_magic2 == DISKMAGIC) {
+                               /* Sanity check */
+                               if (dlp->d_npartitions <= MAXPARTITIONS && 
+                                   dkcksum(dlp) == 0) {
+                                       *lp = *dlp;
+                                       match = -1;
+                                       break;
+#ifdef DIAGNOSTIC
+                               } else {
+                                       printf("read_bsd_label() found "
+                                           "damaged disklabel starting at "
+                                           "0x0%p, ignore\n", dlp);
+#endif /* DIAGNOSTIC */
+                               }
+                       }
+               }
+               if (!match)
+                       msg = "BSD disklabel not found";
+       }
+       brelse(bp, 0);
+       return msg;
+}
+
 /* Read MS-DOS partition table.
  *
  * XXX -
@@ -597,8 +671,9 @@
                        if (!msg)
                                osdep->cd_start = 0;
                } else {
-                       msg = "no disk label -- NetBSD or Macintosh";
-                       osdep->cd_start = 0;    /* XXX for now */
+                       msg = read_bsd_label(dev, strat, lp, osdep);
+                       if (!msg)
+                               osdep->cd_start = 0;    /* XXX for now */
                }
        }