Bug#666255: [grub-installer] Does not verify list of other operating systems when multiple targets (HDDs) detected
Package: grub-installer
Version: 1.70
Severity: normal
grub-installer generally prompts once, to confirm the list of other
operating systems detected:
Template: grub-installer/with_other_os
Type: boolean
Default: true
# :sl1:
_Description: Install the GRUB boot loader to the master boot record?
The following other operating systems have been detected on this
computer: ${OS_LIST}
.
If all of your operating systems are listed above, then it should be safe to
install the boot loader to the master boot record of your first hard
drive. When your computer boots, you will be able to choose to load one of
these operating systems or your new system.
This is not always the case however. When several possible target
devices for installing GRUB are detected, grub-installer prompts:
Template: grub-installer/bootdev
Type: string
# :sl2:
_Description: Device for boot loader installation:
You need to make the newly installed system bootable, by installing
the GRUB boot loader on a bootable device. The usual way to do this is to
install GRUB on the master boot record of your first hard drive. If you
prefer, you can install GRUB elsewhere on the drive, or to another drive,
or even to a floppy.
.
The device should be specified as a device in /dev. Below are some
examples:
- "/dev/sda" will install GRUB to the master boot record of your first
hard drive;
- "/dev/sda2" will use the second partition of your first hard drive;
- "/dev/sdc5" will use the first extended partition of your third hard
drive;
- "/dev/fd0" will install GRUB to a floppy.
This prompt is good in this case, but it does not *replace*
with_other_os. The list of other operating systems still needs to be
confirmed.
When no other operating systems are detected, the prompt is phrased
differently, but the idea is the same:
Template: grub-installer/only_debian
Type: boolean
Default: true
# :sl1:
_Description: Install the GRUB boot loader to the master boot record?
It seems that this new installation is the only operating system
on this computer. If so, it should be safe to install the GRUB boot loader
to the master boot record of your first hard drive.
.
Warning: If the installer failed to detect another operating system that
is present on your computer, modifying the master boot record will make
that operating system temporarily unbootable, though GRUB can be manually
configured later to boot it.
However, the phrasing here mixes a question about the target with a
question whether to install GRUB in general. This should simply say
"Install the GRUB boot loader?" Same for with_other_os, in fact.
Hum, there's a lot of cleanup to do here...
The code relevant to this specific problem is:
574 while : ; do
575 if [ "$state" = 1 ]; then
576 db_input high $q || true
577 if ! db_go; then
578 # back up to menu
579 db_progress STOP
580 exit 10
581 fi
582 db_get $q
583 if [ "$RET" = true ]; then
584 bootdev="$default_bootdev"
585 break
586 else
587 # Exit to menu if /boot is on SATA
RAID/multipath; we
588 # don't support device selection in that case
589 if [ "$frdev" ]; then
590 db_progress STOP
591 exit 10
592 fi
593 state=2
594 fi
595 elif [ "$state" = 2 ]; then
596 db_input critical grub-installer/bootdev || true
597 if ! db_go; then
598 if [ "$q" ]; then
599 state=1
600 else
601 # back up to menu
602 db_progress STOP
603 exit 10
604 fi
605 else
606 db_get grub-installer/bootdev
607 bootdev=$RET
608 if echo "$bootdev" | grep -qv '('; then
609 mappedbootdev=$(mapdevfs
"$bootdev") || true
610 if [ -n "$mappedbootdev" ]; then
611 bootdev="$mappedbootdev"
612 fi
613 fi
614 break
615 fi
616 else
617 break
618 fi
619 done
This could be solved by setting state to 1 at the end of the else (line
613). But then, grub-installer would prompt for bootdev and only then
for only_debian/with_other_os, which would mean asking where to install
before asking whether to install. I think this loop should be simplified
to 2 loops, a first that unconditionally (priority high) requests a
confirmation of detected other OS-es, and a second that may prompt for
GRUB's target. The state variable is too complicated. It should be
replaced by a simple boolean, say $severalbootdevices, if nothing else
needs to be stored.
The relevant variables are set above, basically:
496 if [ -n "$unsupported_os_list" ]; then
497 # Unsupported OS, jump straight to manual boot
device question.
498 state=2
499 else
500 q=grub-installer/with_other_os
501 db_subst $q OS_LIST "$supported_os_list"
502 state=1
503 fi
504 else
505 q=grub-installer/only_debian
506 state=1
507 fi
508
By the way, bootdev is not asked when a single boot device exists, but
it allows to install to a partition rather than to the MBR, which is
useful even if a single HDD is detected. It seems to me the question
should be asked at lowest priority in any case, and at critical priority
when several boot devices are detected.
This doesn't look too hard, but I'm not sure what the parts about
frdev/multipath do.
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