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| -rw-r--r-- | COPYING | 340 | ||||
| -rw-r--r-- | ChangeLog | 1 | ||||
| -rw-r--r-- | docs/overview | 123 |
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diff --git a/COPYING b/COPYING new file mode 100644 index 0000000000..5b6e7c66c2 --- /dev/null +++ b/COPYING @@ -0,0 +1,340 @@ + GNU GENERAL PUBLIC LICENSE + Version 2, June 1991 + + Copyright (C) 1989, 1991 Free Software Foundation, Inc. + 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + Everyone is permitted to copy and distribute verbatim copies + of this license document, but changing it is not allowed. + + Preamble + + The licenses for most software are designed to take away your +freedom to share and change it. By contrast, the GNU General Public +License is intended to guarantee your freedom to share and change free +software--to make sure the software is free for all its users. This +General Public License applies to most of the Free Software +Foundation's software and to any other program whose authors commit to +using it. (Some other Free Software Foundation software is covered by +the GNU Library General Public License instead.) You can apply it to +your programs, too. + + When we speak of free software, we are referring to freedom, not +price. Our General Public Licenses are designed to make sure that you +have the freedom to distribute copies of free software (and charge for +this service if you wish), that you receive source code or can get it +if you want it, that you can change the software or use pieces of it +in new free programs; and that you know you can do these things. + + To protect your rights, we need to make restrictions that forbid +anyone to deny you these rights or to ask you to surrender the rights. +These restrictions translate to certain responsibilities for you if you +distribute copies of the software, or if you modify it. + + For example, if you distribute copies of such a program, whether +gratis or for a fee, you must give the recipients all the rights that +you have. You must make sure that they, too, receive or can get the +source code. And you must show them these terms so they know their +rights. + + We protect your rights with two steps: (1) copyright the software, and +(2) offer you this license which gives you legal permission to copy, +distribute and/or modify the software. + + Also, for each author's protection and ours, we want to make certain +that everyone understands that there is no warranty for this free +software. If the software is modified by someone else and passed on, we +want its recipients to know that what they have is not the original, so +that any problems introduced by others will not reflect on the original +authors' reputations. + + Finally, any free program is threatened constantly by software +patents. We wish to avoid the danger that redistributors of a free +program will individually obtain patent licenses, in effect making the +program proprietary. To prevent this, we have made it clear that any +patent must be licensed for everyone's free use or not licensed at all. + + The precise terms and conditions for copying, distribution and +modification follow. + + GNU GENERAL PUBLIC LICENSE + TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION + + 0. This License applies to any program or other work which contains +a notice placed by the copyright holder saying it may be distributed +under the terms of this General Public License. The "Program", below, +refers to any such program or work, and a "work based on the Program" +means either the Program or any derivative work under copyright law: +that is to say, a work containing the Program or a portion of it, +either verbatim or with modifications and/or translated into another +language. (Hereinafter, translation is included without limitation in +the term "modification".) Each licensee is addressed as "you". + +Activities other than copying, distribution and modification are not +covered by this License; they are outside its scope. The act of +running the Program is not restricted, and the output from the Program +is covered only if its contents constitute a work based on the +Program (independent of having been made by running the Program). +Whether that is true depends on what the Program does. + + 1. You may copy and distribute verbatim copies of the Program's +source code as you receive it, in any medium, provided that you +conspicuously and appropriately publish on each copy an appropriate +copyright notice and disclaimer of warranty; keep intact all the +notices that refer to this License and to the absence of any warranty; +and give any other recipients of the Program a copy of this License +along with the Program. + +You may charge a fee for the physical act of transferring a copy, and +you may at your option offer warranty protection in exchange for a fee. + + 2. You may modify your copy or copies of the Program or any portion +of it, thus forming a work based on the Program, and copy and +distribute such modifications or work under the terms of Section 1 +above, provided that you also meet all of these conditions: + + a) You must cause the modified files to carry prominent notices + stating that you changed the files and the date of any change. + + b) You must cause any work that you distribute or publish, that in + whole or in part contains or is derived from the Program or any + part thereof, to be licensed as a whole at no charge to all third + parties under the terms of this License. + + c) If the modified program normally reads commands interactively + when run, you must cause it, when started running for such + interactive use in the most ordinary way, to print or display an + announcement including an appropriate copyright notice and a + notice that there is no warranty (or else, saying that you provide + a warranty) and that users may redistribute the program under + these conditions, and telling the user how to view a copy of this + License. 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But when you +distribute the same sections as part of a whole which is a work based +on the Program, the distribution of the whole must be on the terms of +this License, whose permissions for other licensees extend to the +entire whole, and thus to each and every part regardless of who wrote it. + +Thus, it is not the intent of this section to claim rights or contest +your rights to work written entirely by you; rather, the intent is to +exercise the right to control the distribution of derivative or +collective works based on the Program. + +In addition, mere aggregation of another work not based on the Program +with the Program (or with a work based on the Program) on a volume of +a storage or distribution medium does not bring the other work under +the scope of this License. + + 3. You may copy and distribute the Program (or a work based on it, +under Section 2) in object code or executable form under the terms of +Sections 1 and 2 above provided that you also do one of the following: + + a) Accompany it with the complete corresponding machine-readable + source code, which must be distributed under the terms of Sections + 1 and 2 above on a medium customarily used for software interchange; or, + + b) Accompany it with a written offer, valid for at least three + years, to give any third party, for a charge no more than your + cost of physically performing source distribution, a complete + machine-readable copy of the corresponding source code, to be + distributed under the terms of Sections 1 and 2 above on a medium + customarily used for software interchange; or, + + c) Accompany it with the information you received as to the offer + to distribute corresponding source code. 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The Free Software Foundation may publish revised and/or new versions +of the General Public License from time to time. Such new versions will +be similar in spirit to the present version, but may differ in detail to +address new problems or concerns. + +Each version is given a distinguishing version number. If the Program +specifies a version number of this License which applies to it and "any +later version", you have the option of following the terms and conditions +either of that version or of any later version published by the Free +Software Foundation. If the Program does not specify a version number of +this License, you may choose any version ever published by the Free Software +Foundation. + + 10. If you wish to incorporate parts of the Program into other free +programs whose distribution conditions are different, write to the author +to ask for permission. For software which is copyrighted by the Free +Software Foundation, write to the Free Software Foundation; we sometimes +make exceptions for this. Our decision will be guided by the two goals +of preserving the free status of all derivatives of our free software and +of promoting the sharing and reuse of software generally. + + NO WARRANTY + + 11. BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY +FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN +OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES +PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED +OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF +MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS +TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU. SHOULD THE +PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING, +REPAIR OR CORRECTION. + + 12. IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING +WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR +REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, +INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING +OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED +TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY +YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER +PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE +POSSIBILITY OF SUCH DAMAGES. + + END OF TERMS AND CONDITIONS + + How to Apply These Terms to Your New Programs + + If you develop a new program, and you want it to be of the greatest +possible use to the public, the best way to achieve this is to make it +free software which everyone can redistribute and change under these terms. + + To do so, attach the following notices to the program. It is safest +to attach them to the start of each source file to most effectively +convey the exclusion of warranty; and each file should have at least +the "copyright" line and a pointer to where the full notice is found. + + <one line to give the program's name and a brief idea of what it does.> + Copyright (C) <year> <name of author> + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 2 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + + +Also add information on how to contact you by electronic and paper mail. + +If the program is interactive, make it output a short notice like this +when it starts in an interactive mode: + + Gnomovision version 69, Copyright (C) year name of author + Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type `show w'. + This is free software, and you are welcome to redistribute it + under certain conditions; type `show c' for details. + +The hypothetical commands `show w' and `show c' should show the appropriate +parts of the General Public License. Of course, the commands you use may +be called something other than `show w' and `show c'; they could even be +mouse-clicks or menu items--whatever suits your program. + +You should also get your employer (if you work as a programmer) or your +school, if any, to sign a "copyright disclaimer" for the program, if +necessary. Here is a sample; alter the names: + + Yoyodyne, Inc., hereby disclaims all copyright interest in the program + `Gnomovision' (which makes passes at compilers) written by James Hacker. + + <signature of Ty Coon>, 1 April 1989 + Ty Coon, President of Vice + +This General Public License does not permit incorporating your program into +proprietary programs. If your program is a subroutine library, you may +consider it more useful to permit linking proprietary applications with the +library. If this is what you want to do, use the GNU Library General +Public License instead of this License. diff --git a/ChangeLog b/ChangeLog new file mode 100644 index 0000000000..6a7969d298 --- /dev/null +++ b/ChangeLog @@ -0,0 +1 @@ +0.1 - initial release diff --git a/docs/overview b/docs/overview new file mode 100644 index 0000000000..6528b058c2 --- /dev/null +++ b/docs/overview @@ -0,0 +1,123 @@ + +Instead of heading in on another "proposal" document, I thought I'd send out +this email describing ideas I've had about udev - thanks to the comments I've +received. The idea is starting to mushroom a bit and I'd like to get people's +comments before I go further down the path. + +As I see it, we've got a couple goals for udev: + +1) dynamic replacement for /dev +2) device naming +3) API to access info about current system devices + +I'd like to split these goals into separate subsystems: + +1) udev - dynamic replacement for /dev +2) namedev - device naming +3) libsysfs - a standard library for accessing device information on the +system. + +Udev +------ + +Udev will be responsible for responding to /sbin/hotplug on device events. It +will receive the device class information along with device's sysfs +directory. Udev will call the name_device function from the naming device +subsystem with that information and receive a unique device name in return. +Udev will then query sysfs through the libsysfs for specific device +information required for creating the /dev node like major and minor number. +Once it has the important information, udev will create a /dev entry for the +device, add the device to the in memory table of current devices, and send +notification of the successful event. On a remove call, udev will remove the +/dev entry, remove the device from the in memory table, and send +notification. + +Udev will consist of a command udev - to be called from /sbin/hotplug. It will +require the in memory dynamic database/table for keeping track of current +system devices, and a library of routines for accessing that database/table. +Udev will not care about "how" devices are named, that will be separated into +the device naming subsystem. It's presented a common device naming API by the +device naming subsystem to use for naming devices. + +namedev +---------- + +From comments Martin has made, I've decided to push out the device naming part +of udev into its own "subsystem". The reason is to make this as flexible and +pluggable as possible. The device naming subsystem, or namedev, will present +a standard interface for udev to call for naming a particular device. Under +that interface, system administrators can plug in their own methods for +device naming. + +We would provide a default naming scheme. The first prototype implementation +could simply take the sysfs directory passed in with the device name +function, query sysfs for the major and minor numbers, and then look up in a +static device name mapping file the name of the device. The static device +naming file could look just like devices.txt in the Linux kernel's +Documentation directory. Obviously, this isn't a great implementation because +eventually we'd like major an minor numbers to be dynamic. + +The default naming scheme in the future would have a set of policies to go +through, these were given to me by Greg. The device naming subsystem would +get the sysfs directory of the to be named device and would use the following +information in order to map the device's name: + +1) Label info - like SCSI's UUID +2) Bus Device Number +3) Topology on Bus +4) Kernel Name - DEFAULT + +System administrators could use the default naming system or enterprise +computing environments could plug in their Universal Unique Identifier (UUID) +policies. The idea is to make the device naming as flexible and pluggable as +possible. + +The device naming subsystem would require accessing sysfs for device +information. It will receive the device's sysfs directory in the call from +udev and use it to get more information to determine naming. The namedev +subsystem will include a standard naming API for udev to use. The default +naming scheme will include a set of functions and a static device naming +file, which will reside in /etc or /var. + +libsysfs +-------- + +Greg may object, but I believe there's a need for a common API to access +device information in sysfs. The device naming subsystem and the udev +subsystem need to take the sysfs directory path and query device information. +Instead of copying code so each one will have to readdir, etc., I've decided +to split out the sysfs calls into a separate library that will sit atop +sysfs. Sysfs callbacks aren't standard across devices, I beleive this is +another reason for creating a common and standard library interface for +querying device information. + +Another reason for libsysfs is it satisfies requirements the LTC RAS team has +for getting current system device information. Rather than keeping tons of +information in udev's in memory database, or even querying that database for +the sysfs directory that will require storing extra reference info in memory, +I've decided the RAS requirements can be fulfilled with a library atop sysfs. +Sysfs contains devices currently on the system. + +Applications like the Error Log Analysis piece, for example, can query the +sysfs library for device information. ELA gets specific information in an +error message thanks to the dev_* and soon to be proposed netdev_* macros. +One goal of the ELA is to gather as much information about an erroring device +so service engineers and administrators can diagnose the problem. The ELA +will get an error message with the bus id and driver name of the device. It +will then need to query sysfs for other VPD information. + +I've used syfs in the name of libsysfs for a reason, I believe sysfs will be +the device tree to use in the future. Until all VPD info is in sysfs, the +library could also make use of /proc, sginfo, and other sources for device +information under the covers so ELA and other applications don' t need to all +have that knowledge. + + +I'd like to know what everyone thinks about my proposal to split this all up +into three separate subsystems. All comments are welcome. + +Thanks, + +Dan + + |