Re: fdisk flag bootable partition during install

[Matthew Dempsky]

On Tue, Apr 24, 2012 at 08:14:19PM +0200, Alexander Hall wrote:
> You do not flag which "to use". Multiple A6 entries brings problems
> since you get multiple disklabels.

Perhaps it's worthwhile for fdisk to sanity check for errors like this
before writing out an MBR?

Index: cmd.c
===================================================================
RCS file: /home/mdempsky/anoncvs/cvs/src/sbin/fdisk/cmd.c,v
retrieving revision 1.46
diff -u -p -r1.46 cmd.c
--- cmd.c       11 Nov 2011 18:21:06 -0000      1.46
+++ cmd.c       25 Apr 2012 03:00:16 -0000
@@ -328,7 +328,16 @@ int
 Xwrite(cmd_t *cmd, disk_t *disk, mbr_t *mbr, mbr_t *tt, int offset)
 {
        char mbr_buf[DEV_BSIZE];
-       int fd;
+       int fd, i, n;
+
+       for (i = 0, n = 0; i < NDOSPART; i++)
+               if (mbr->part[i].id == 0xA6)
+                       n++;
+       if (n >= 2) {
+               warnx("MBR contains more than one OpenBSD partition!");
+               if (!ask_yn("Write MBR anyway?"))
+                       return (CMD_CONT);
+       }
 
        fd = DISK_open(disk->name, O_RDWR);
        MBR_make(mbr, mbr_buf);