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dump using mechanically generated/extracted debugging output rather than a simple memory dump. Current sources of debugging output are: - DDB output capture buffer, if there is captured output to save - Kernel message buffer - Kernel configuration, if included in kernel - Kernel version string - Panic message Textdumps are stored in swap/dump partitions as with regular dumps, but are laid out as ustar files in order to allow multiple parts to be stored as a stream of sequentially written blocks. Blocks are written out in reverse order, as the size of a textdump isn't known a priori. As with regular dumps, they will be extracted using savecore(8). One new DDB(4) command is added, "textdump", which accepts "set", "unset", and "status" arguments. By default, normal kernel dumps are generated unless "textdump set" is run in order to schedule a textdump. It can be canceled using "textdump unset" to restore generation of a normal kernel dump. Several sysctls exist to configure aspects of textdumps; debug.ddb.textdump.pending can be set to check whether a textdump is pending, or set/unset in order to control whether the next kernel dump will be a textdump from userspace. While textdumps don't have to be generated as a result of a DDB script run automatically as part of a kernel panic, this is a particular useful way to use them, as instead of generating a complete memory dump, a simple transcript of an automated DDB session can be captured using the DDB output capture and textdump facilities. This can be used to generate quite brief kernel bug reports rich in debugging information but not dependent on kernel symbol tables or precisely synchronized source code. Most textdumps I generate are less than 100k including the full message buffer. Using textdumps with an interactive debugging session is also useful, with capture being enabled/disabled in order to record some but not all of the DDB session. MFC after: 3 months
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. 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