FreeBSD src
other than the one specified by the BOOTP server. This configures NFS using the BOOTP protocol while also respecting other root-path options such as setting vfs.root.mountfrom in the environment or using the RB_DFLTROOT boot option. It allows you to override the root path provided by the server, or to supply a root path when the server provides IP configuration but no root path info. This maintains the historical BOOTP_NFSROOT behavior of panicking on a failure to mount the root path provided by the server, unless you've provided an alternative via the ROOTDEVNAME kernel option or by setting vfs.root.mountfrom. The behavior of panicking when given no other options is preserved because it amounts to a bit of a retry loop that could eventually recover from a transient network or server problem. The user can now override the root path from loader(8) even if the kernel is compiled with BOOTP_NFSROOT. If vfs.root.mountfrom is set in the environment it is used unconditionally -- it always overrides the BOOTP info. If it begins with [old]nfs: then the BOOTP code uses it instead of the server-provided info. If it specifies some other filesystem then the bootp code will not panic like it used to and the code in vfs_mountroot.c will invoke the right filesystem to do the mount. If the kernel is compiled with the ROOTDEVNAME option, then that name is used by the BOOTP code if either * The server doesn't provide a pathname. * The boothowto flags include RB_DFLTROOT. The latter allows the user to compile in alternate path in ROOTDEVNAME such as ufs:/dev/da0s1a and boot from that path by setting boot_dftlroot=1 in loader(8) or using the '-r' option in boot(8). The one thing not provided here is automatic failover from a server-provided path to a compiled-in one without the user manually requesting that. The code just isn't currently structured in a way that makes that possible with a lot of rewrite. I think the ability to set vfs.root.mountfrom and to use ROOTDEVNAME automatically when the server doesn't provide a name covers the most common needs. A set of patches submitted by Lars Eggert provided the part I couldn't figure out by myself when I tried to do this last year; many thanks. Reviewed by: rodrigc |
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bin | ||
cddl | ||
contrib | ||
crypto | ||
etc | ||
games | ||
gnu | ||
include | ||
kerberos5 | ||
lib | ||
libexec | ||
release | ||
rescue | ||
sbin | ||
secure | ||
share | ||
sys | ||
tools | ||
usr.bin | ||
usr.sbin | ||
COPYRIGHT | ||
LOCKS | ||
MAINTAINERS | ||
Makefile | ||
Makefile.inc1 | ||
ObsoleteFiles.inc | ||
README | ||
UPDATING |
This is the top level of the FreeBSD source directory. This file was last revised on: $FreeBSD$ For copyright information, please see the file COPYRIGHT in this directory (additional copyright information also exists for some sources in this tree - please see the specific source directories for more information). The Makefile in this directory supports a number of targets for building components (or all) of the FreeBSD source tree, the most commonly used one being ``world'', which rebuilds and installs everything in the FreeBSD system from the source tree except the kernel, the kernel-modules and the contents of /etc. The ``world'' target should only be used in cases where the source tree has not changed from the currently running version. See: http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/makeworld.html for more information, including setting make(1) variables. The ``buildkernel'' and ``installkernel'' targets build and install the kernel and the modules (see below). Please see the top of the Makefile in this directory for more information on the standard build targets and compile-time flags. Building a kernel is a somewhat more involved process, documentation for which can be found at: http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/kernelconfig.html And in the config(8) man page. Note: If you want to build and install the kernel with the ``buildkernel'' and ``installkernel'' targets, you might need to build world before. More information is available in the handbook. The sample kernel configuration files reside in the sys/<arch>/conf sub-directory (assuming that you've installed the kernel sources), the file named GENERIC being the one used to build your initial installation kernel. The file NOTES contains entries and documentation for all possible devices, not just those commonly used. It is the successor of the ancient LINT file, but in contrast to LINT, it is not buildable as a kernel but a pure reference and documentation file. Source Roadmap: --------------- bin System/user commands. cddl Various commands and libraries under the Common Development and Distribution License. contrib Packages contributed by 3rd parties. crypto Cryptography stuff (see crypto/README). etc Template files for /etc. games Amusements. gnu Various commands and libraries under the GNU Public License. Please see gnu/COPYING* for more information. include System include files. kerberos5 Kerberos5 (Heimdal) package. lib System libraries. libexec System daemons. release Release building Makefile & associated tools. rescue Build system for statically linked /rescue utilities. sbin System commands. secure Cryptographic libraries and commands. share Shared resources. sys Kernel sources. tools Utilities for regression testing and miscellaneous tasks. usr.bin User commands. usr.sbin System administration commands. For information on synchronizing your source tree with one or more of the FreeBSD Project's development branches, please see: http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/synching.html