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OPNsense - FreeBSD source
852a0932c1
that keeps track of a particular region of the image. In particular the image_data() function needs to return to the caller whether a region contains data or is all zeroes. This required reading the region from the temporary file and comparing the bytes. When image_data() is used multiple times for the same region, this will get painful fast. With a chunk describing a region of the image, we now also have a way to refer to the image provided on the command line. This means we don't need to copy the image into a temporary file. We just keep track of the file descriptor and offset within the source file on a per-chunk basis. For streams (pipes, sockets, fifos, etc) we now use the temporary file as a swap file. We read from the input file and create a chunk of type "zeroes" for each sequence of zeroes that's a multiple of the sector size. Otherwise, we allocte from the swap file, mmap(2) it, read into the mmap(2)'d memory and create a chunk representing data. For regular files, we use SEEK_HOLE and SEEK_DATA to handle sparse files eficiently and create a chunk of type zeroes for holes and a chunk of type data for data regions. For data regions, we still compare the bytes we read to handle differences between a file system's block size and our sector size. After reading all files, image_write() is used by schemes to scribble in the reserved sectors. Since this never amounts to much, keep this data in memory in chunks of exactly 1 sector. The output image is created by looking using the chunk list to find the data and write it out to the output file. For chunks of type "zeroes" we prefer to seek, but fall back to writing zeroes to handle pipes. For chunks of type "file" and "memoty" we simply write. The net effect of this is that for reasonably large images the execution time drops from 1-2 minutes to 10-20 seconds. A typical speedup is about 5 to 8 times, depending on partition sizes, output format whether in input files are sparse or not. Bump version to 20141001. |
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| bin | ||
| cddl | ||
| contrib | ||
| crypto | ||
| etc | ||
| games | ||
| gnu | ||
| include | ||
| kerberos5 | ||
| lib | ||
| libexec | ||
| release | ||
| rescue | ||
| sbin | ||
| secure | ||
| share | ||
| sys | ||
| tests | ||
| tools | ||
| usr.bin | ||
| usr.sbin | ||
| .arcconfig | ||
| .arclint | ||
| 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