I am submitting the following fast-track on behalf of Konstanin Ananyev
and Sherry Moore. Minor release binding is requested. The timeout is
set for 02-18-2009.
-jg
1. Introduction
1.1. Project/Component Working Name:
Introducing libgrubmgmt library for GRUB menu management.
1.2. Name of Document Author/Supplier:
Konstantin Ananyev
1.3. Date of This Document:
01/07/2009
1.3.1. Date this project was conceived:
06/01/2008
2. Project Summary
2.1. Project Description:
This project will provide a library to process the GRUB menu. The
library libgrubmgmt provides APIs to locate the active menu.lst,
parse it and interpret GRUB menu entries.
2.2 Risks and Assumptions:
This project has dependencies on stable GRUB menu format for
Solaris.
4. Technical Description:
4.1. Details:
The library libgrubmgmt provides APIs to locate the active
menu.lst, parse the menu and interpret GRUB menu entries. It
will interpret the following GRUB menu entry commands:
findroot, bootfs, kernel, kernel$, module, module$.
When Fast Reboot is enabled either by setting the
"config/fastreboot_default" property in "system/boot-config"
service to "true", or by invoking reboot(1M) with the "-f"
option directly, the library will be used by commands
reboot(1M) or init(1M) 6 to extract boot arguments associated
with the default or specified menu entry from menu.lst. If
libgrubmgmt fails to interpret the GRUB menu entry, reboot(1M)
and init(1M) would fall back to the regular reboot behavior.
4.1.1 APIs and Consumers
With initial integration, the consumers of the library are
reboot(1M) and init(1M) on x86. They are only using the
two of the interfaces listed in section 4.5 Interfaces
grub_get_boot_args()
grub_cleanup_boot_args()
Other utilities that manipulate GRUB menus, such as
bootadm(1M), can be modified to leverage this library, at
which point additional interfaces can be ARC'ed.
4.1.2 Examples
On systems with "config/fastreboot_default" set to "true":
# reboot
# init 6
Fast reboot with bootargs from the default GRUB menu
entry.
# reboot 3
Fast reboot with bootargs from the 3rd GRUB menu entry.
For example for the following default GRUB menu entry:
title benew1
findroot (BE_benew1,0,a)
bootfs rpool/ROOT/benew1
kernel$ /platform/i86pc/kernel/$ISADIR/unix -B $ZFS-BOOTFS
module$ /platform/i86pc/$ISADIR/boot_archive
# reboot
is equivalent to:
# reboot -f -- rpool/ROOT/benew1 \
/platform/i86pc/kernel/amd64/unix \
-B zfs-bootfs=rpool/ROOT/benew1,\
bootpath="/pci at 0,0/pci10de,5c at 9/pci108e,4131 at 1/sd at
0,0:a"
4.2. Bug/RFE Number(s):
6768468 Introducing svc:/system/boot-config service
6775160 reboot -f ignores active BE and resets zfs pool bootfs property
4.5. Interfaces:
Minor binding only.
INTERFACE COMMITMENT LEVEL
=====================================================
/lib/libgrubmgmt.so.1 consolidation private
/lib/libgrubmgmt.so consolidation private
/usr/include/libgrubmgmt.h consolidation private
SUNWgrubu consolidation private
grub_get_boot_args() consolidation private
grub_cleanup_boot_args() consolidation private
grub_strerror() consolidation private
4.6. Doc Impact:
Man pages for reboot(1M) needs to be modified.
4.6.1 Man pages for reboot(1M)
Example 3 Fast Rebooting
The following examples use the f option to perform fast
reboots.
The following command reboots to the default entry in the grub |
menu file menu.lst. |
example# reboot -f
4.6.2 New man pages for libgrubmgmt
See appendix A.
4.7. Admin/Config Impact
The System Administration Guide needs to be updated to reflect
the change in the behavior when no command line arguments are
provided to reboot(1M).
6. Resources and Schedule:
6.4. Steering Committee requested information
6.4.1. Consolidation C-team Name:
ON
6.5. ARC review type: FastTrack
6.6. ARC Exposure: open
Appendix A
GRUB Menu Management Library Functions
grubmgmt(3GRUBMGMT)
NAME
grub_get_boot_args - collect boot argument from the specified GRUB
menu entry. If entrynum == -1, default GRUB menu entry will be used.
grub_cleanup_boot_args - clean up and releases all the resources
allocated by grub_get_boot_args.
SYNOPSIS
cc [ flag... ] file... -lgrubmgmt [ library... ]
#include <libgrubmgmt.h>
int grub_get_boot_args(grub_boot_args_t *bargs, int entrynum);
void grub_cleanup_boot_args(grub_boot_args_t *bargs);
PARAMETERS
entrynum Integer representing the entry or line number
in the menu.
bargs Pointer to boot argument data structure.
DESCRIPTION
The grub_get_boot_args() function returns the boot arguments from
the specified GRUB menu entry in the first argument. If entrynum
is -1, default GRUB menu entry will be used. Caller must allocate
grub_boot_args_t and call the function with a pointer to it as its
first argument.
The grub_cleanup_boot_args() function clean up and releases all the
resources allocated by grub_get_boot_args().
RETURN VALUES
grub_get_boot_args() returns zero on success and an error value on
failrue. See errno.h for details.
ATTRIBUTES
See attributes(5) for descriptions of the following attri-
butes:
____________________________________________________________
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
|_____________________________|_____________________________|
| Interface Stability | Evolving |
|_____________________________|_____________________________|
| MT-Level | Safe |
|_____________________________|_____________________________|
SEE ALSO
errno.h(3HEAD)
