{ "mode": "info", "parameter": "find-maint", "section": "", "url": "https://www.chedong.com/phpMan.php/info/find-maint/json", "generated": "2026-07-31T02:25:45Z", "sections": { "File: find-maint.info, Node: Top, Next: Introduction, Prev: (dir), Up: (dir)": { "content": "", "subsections": [] }, "Maintaining GNU Findutils": { "content": "", "subsections": [] }, "This manual explains how GNU findutils is maintained, how changes should": { "content": "be made and tested, and what resources exist to help developers.\n\nThis document corresponds to version 4.8.0 of the GNU findutils.\n\nCopyright (C) 2007-2021 Free Software Foundation, Inc.\n\nPermission is granted to copy, distribute and/or modify this\ndocument under the terms of the GNU Free Documentation License,\nVersion 1.3 or any later version published by the Free Software\nFoundation; with no Invariant Sections, no Front-Cover Texts, and\nno Back-Cover Texts. A copy of the license is included in the\nsection entitled \"GNU Free Documentation License\".\n\n* Menu:\n\n* Introduction::\n* Maintaining GNU Programs::\n* Design Issues::\n* Coding Conventions::\n* Tools::\n* Using the GNU Portability Library::\n* Documentation::\n* Testing::\n* Bugs::\n* Distributions::\n* Internationalisation::\n* Security::\n* Making Releases::\n* GNU Free Documentation License::\n", "subsections": [] }, "File: find-maint.info, Node: Introduction, Next: Maintaining GNU Programs, Up: Top": { "content": "", "subsections": [] }, "1 Introduction": { "content": "This document explains how to contribute to and maintain GNU Findutils.", "subsections": [] }, "It concentrates on developer-specific issues. For information about how": { "content": "to use the software please refer to *Note Introduction:\n(find)Introduction.\n\nThis manual aims to be useful without necessarily being verbose.", "subsections": [] }, "It's also a recent document, so there will be a many areas in which": { "content": "improvements can be made. If you find that the document misses out\nimportant information or any part of the document is be so terse as to\nbe unuseful, please ask for help on the mailing\nlist. We'll try to improve this document too.\n", "subsections": [] }, "File: find-maint.info, Node: Maintaining GNU Programs, Next: Design Issues, Prev: Introduction, Up: Top": { "content": "", "subsections": [] }, "2 Maintaining GNU Programs": { "content": "GNU Findutils is part of the GNU Project and so there are a number of\ndocuments which set out standards for the maintenance of GNU software.\n\n'standards.texi'\nGNU Project Coding Standards. All changes to findutils should\ncomply with these standards. In some areas we go somewhat beyond\nthe requirements of the standards, but these cases are explained in\nthis manual.\n'maintain.texi'\nInformation for Maintainers of GNU Software. This document\nprovides guidance for GNU maintainers. Everybody with commit\naccess should read this document. Everybody else is welcome to do\nso too, of course.\n", "subsections": [] }, "File: find-maint.info, Node: Design Issues, Next: Coding Conventions, Prev: Maintaining GNU Programs, Up: Top": { "content": "", "subsections": [] }, "3 Design Issues": { "content": "", "subsections": [] }, "The findutils package is installed on many many systems, usually as a": { "content": "fundamental component. The programs in the package are often used in\norder to successfully boot or fix the system.\n\nThis fact means that for findutils we bear in mind considerations\nthat may not apply so much as for other packages. For example, the fact\nthat findutils is often a base component motivates us to\n* Limit dependencies on libraries\n* Avoid dependencies on other large packages (for example,\ninterpreters)\n* Be conservative when making changes to the 'stable' release branch\n\nAll those considerations come before functionality. Functional\nenhancements are still made to findutils, but these are almost\nexclusively introduced in the 'development' release branch, to allow\nextensive testing and proving.\n\nSometimes it is useful to have a priority list to provide guidance\nwhen making design trade-offs. For findutils, that priority list is:\n\n1. Correctness\n2. Standards compliance\n3. Security\n4. Backward compatibility\n5. Performance\n6. Functionality\n\nFor example, we support the '-exec' action because POSIX compliance\nrequires this, even though there are security problems with it and we\nwould otherwise prefer people to use '-execdir'. There are also cases\nwhere some performance is sacrificed in the name of security. For\nexample, the sanity checks that 'find' performs while traversing a\ndirectory tree may slow it down. We adopt functional changes, and\nfunctional changes are allowed to make 'find' slower, but only if there\nis no detectable impact on users who don't use the feature.\n\nBackward-incompatible changes do get made in order to comply with\nstandards (for example the behaviour of '-perm -...' changed in order to\ncomply with POSIX). However, they don't get made in order to provide\nbetter ease of use; for example the semantics of '-size -2G' are almost\nalways unexpected by users, but we retain the current behaviour because\nof backward compatibility and for its similarity to the block-rounding\nbehaviour of '-size -30'. We might introduce a change which does not\nhave the unfortunate rounding behaviour, but we would choose another\nsyntax (for example '-size '<2G'') for this.\n\nIn a general sense, we try to do test-driven development of the\nfindutils code; that is, we try to implement test cases for new features\nand bug fixes before modifying the code to make the test pass. Some\nfeatures of the code are tested well, but the test coverage for other\nfeatures is less good. If you are about to modify the code for a\npredicate and aren't sure about the test coverage, use 'grep' on the\ntest directories and measure the coverage with 'lcov' or another test\ncoverage tool.\n\nYou should be able to use the 'coverage' Makefile target (it's\ndefined in 'maint.mk' to generate a test coverage report for findutils.", "subsections": [] }, "Due to limitations in 'lcov', this only works if your build directory is": { "content": "the same asthe source directory (that is, you're not using a VPATH build\nconfiguration).\n\nLastly, we try not to depend on having a \"working system\". The\nfindutils suite is used for diagnosis of problems, and this applies\nespecially to 'find'. We should ensure that 'find' still works on\nrelatively broken systems, for example systems with damaged\n'/etc/passwd' or '/etc/fstab' files. Another interesting example is the\ncase where a system is a client of one or more unresponsive NFS servers.", "subsections": [] }, "On such a system, if you try to stat all mount points, your program will": { "content": "hang indefinitely, waiting for the remote NFS server to respond.\n\nAnother interesting but unusual case is broken NFS servers and\ncorrupt filesystems; sometimes they return 'impossible' file modes.", "subsections": [] }, "It's important that find does not entirely fail when encountering such a": { "content": "file.\n", "subsections": [] }, "File: find-maint.info, Node: Coding Conventions, Next: Tools, Prev: Design Issues, Up: Top": { "content": "", "subsections": [] }, "4 Coding Conventions": { "content": "", "subsections": [] }, "Coding style documents which set out to establish a uniform look and": { "content": "feel to source code have worthy goals, for example greater ease of\nmaintenance and readability. However, I do not believe that in general\ncoding style guide authors can envisage every situation, and it is\nalways possible that it might on occasion be necessary to break the\nletter of the style guide in order to honour its spirit, or to better\nachieve the style guide's goals.\n\nI've certainly seen many style guides outside the free software world\nwhich make bald statements such as \"functions shall have exactly one\nreturn statement\". The desire to ensure consistency and obviousness of\ncontrol flow is laudable, but it is all too common for such bald\nrequirements to be followed unthinkingly. Certainly I've seen such\ncoding standards result in unmaintainable code with terrible\ninfelicities such as functions containing 'if' statements nested nine\nlevels deep. I suppose such coding standards don't survive in free\nsoftware projects because they tend to drive away potential contributors\nor tend to generate heated discussions on mailing lists. Equally, a\nnine-level-deep function in a free software program would quickly get\nrefactored, assuming it is obvious what the function is supposed to\ndo...\n\nBe that as it may, the approach I will take for this document is to\nexplain some idioms and practices in use in the findutils source code,\nand leave it up to the reader's engineering judgement to decide which\nconsiderations apply to the code they are working on, and whether or not\nthere is sufficient reason to ignore the guidance in current\ncircumstances.\n\n* Menu:\n\n* Make the Compiler Find the Bugs::\n* Factor Out Repeated Code::\n* Debugging is For Users Too::\n* Don't Trust the File System Contents::\n* The File System Is Being Modified::\n", "subsections": [] }, "File: find-maint.info, Node: Make the Compiler Find the Bugs, Next: Factor Out Repeated Code, Up: Coding Conventions": { "content": "", "subsections": [ { "name": "4.1 Make the Compiler Find the Bugs", "content": "" } ] }, "Finding bugs is tedious. If I have a filesystem containing two million": { "content": "files, and a find command line should print one million of them, but in\nfact it misses out 1%, you can tell the program is printing the wrong\nresult only if you know the right answer for that filesystem at that\ntime. If you don't know this, you may just not find out about that bug.\nFor this reason it is important to have a comprehensive test suite.\n\nThe test suite is of course not the only way to find the bugs. The\nfindutils source code makes liberal use of the assert macro. While on\nthe one hand these might be a performance drain, the performance impact\nof most of these is negligible compared to the time taken to fetch even\none sector from a disk drive.\n\nAssertions should not be used to check the results of operations\nwhich may be affected by the program's external environment. For\nexample, never assert that a file could be opened successfully. Errors\nrelating to problems with the program's execution environment should be\ndiagnosed with a user-oriented error message. An assertion failure\nshould always denote a bug in the program.\n\nAvoid using 'assert' to mark not-fully-implemented features of your\ncode as such. Finish the implementation, disable the code, or leave the\nunfinished version on a local branch.\n\nSeveral programs in the findutils suite perform self-checks. See for\nexample the function 'predsanitycheck' in 'find/pred.c'. This is\ngenerally desirable.\n\nThere are also a number of small ways in which we can help the\ncompiler to find the bugs for us.\n\n\nIt's a common error to write '=' when '==' is meant. Sometimes this\nhappens in new code and is simply due to finger trouble. Sometimes it\nis the result of the inadvertent deletion of a character. In any case,\nthere is a subset of cases where we can persuade the compiler to\ngenerate an error message when we make this mistake; this is where the\nequality test is with a constant.\n\nThis is an example of a vulnerable piece of code.\n\nif (x == 2)\n...\n\nA simple typo converts the above into\n\nif (x = 2)\n...\n\nWe've introduced a bug; the condition is always true, and the value\nof 'x' has been changed. However, a simple change to our practice would\nhave made us immune to this problem:\n\nif (2 == x)\n...\n\nUsually, the Emacs keystroke 'M-t' can be used to swap the operands.\n\n", "subsections": [] }, "Strings in C are just sequences of characters terminated by a NUL. The": { "content": "ASCII NUL character has the numerical value zero. It is normally\nrepresented in C code as '\\0'. Here is a typical piece of C code:\n\n*p = '\\0';\n\nConsider what happens if there is an unfortunate typo:\n\n*p = '0';\n\nWe have changed the meaning of our program and the compiler cannot\ndiagnose this as an error. Our string is no longer terminated. Bad\nthings will probably happen. It would be better if the compiler could\nhelp us diagnose this problem.\n\nIn C, the type of ''\\0'' is in fact int, not char. This provides us\nwith a simple way to avoid this error. The constant '0' has the same\nvalue and type as the constant ''\\0''. However, it is not as vulnerable\nto typos. For this reason I normally prefer to use this code:\n\n*p = 0;\n", "subsections": [] }, "File: find-maint.info, Node: Factor Out Repeated Code, Next: Debugging is For Users Too, Prev: Make the Compiler Find the Bugs, Up: Coding Conventions": { "content": "", "subsections": [ { "name": "4.2 Factor Out Repeated Code", "content": "" } ] }, "Repeated code imposes a greater maintenance burden and increases the": { "content": "exposure to bugs. For example, if you discover that something you want\nto implement has some similarity with an existing piece of code, don't\ncut and paste it. Instead, factor the code out. The risk of cutting\nand pasting the code, particularly if you do this several times, is that\nyou end up with several copies of the same code.\n\nIf the original code had a bug, you now have N places where this\nneeds to be fixed. It's all to easy to miss some out when trying to fix\nthe bug. Equally, it's quite possible that when pasting the code into\nsome function, the pasted code was not quite adapted correctly to its\nnew environment. To pick a contrived example, perhaps it modifies a\nglobal variable which it (that [original] code) shouldn't be touching in\nits new home. Worse, perhaps it makes some unstated assumption about\nthe nature of the input arguments which is in fact not true for the\ncontext of the now duplicated code.\n\nA good example of the use of refactoring in findutils is the\n'collectarg' function in 'find/parser.c'. A less clear-cut but larger\nexample is the factoring out of code which would otherwise have been\nduplicated between 'find/oldfind.c' and 'find/ftsfind.c'.\n\nThe findutils test suite is comprehensive enough that refactoring\ncode should not generally be a daunting prospect from a testing point of\nview. Nevertheless there are some areas which are only lightly-tested:\n\n1. Tests on the ages of files\n2. Code which deals with the values returned by operating system calls\n(for example handling of ENOENT)\n3. Code dealing with OS limits (for example, limits on path length or\nexec arguments)\n4. Code relating to features not all systems have (for example Solaris\nDoors)\n\nPlease exercise caution when working in those areas.\n", "subsections": [] }, "File: find-maint.info, Node: Debugging is For Users Too, Next: Don't Trust the File System Contents, Prev: Factor Out Repeated Code, Up: Coding Conventions": { "content": "", "subsections": [ { "name": "4.3 Debugging is For Users Too", "content": "" } ] }, "Debug and diagnostic code is often used to verify that a program is": { "content": "working in the way its author thinks it should be. But users are often\nuncertain about what a program is doing, too. Exposing them a little\nmore diagnostic information can help. Much of the diagnostic code in\n'find', for example, is controlled by the '-D' flag, as opposed to C\npreprocessor directives.\n\nMaking diagnostic messages available to users also means that the\nphrasing of the diagnostic messages becomes important, too.\n", "subsections": [] }, "File: find-maint.info, Node: Don't Trust the File System Contents, Next: The File System Is Being Modified, Prev: Debugging is For Users Too, Up: Coding Conventions": { "content": "", "subsections": [ { "name": "4.4 Don't Trust the File System Contents", "content": "People use 'find' to search in directories created by other people." } ] }, "Sometimes they do this to check to suspicious activity (for example to": { "content": "look for new setuid binaries). This means that it would be bad if\n'find' were vulnerable to, say, a security problem exploitable by\nconstructing a specially-crafted filename. The same consideration would\napply to 'locate' and 'updatedb'.\n\nHenry Spencer said this well in his fifth commandment:\nThou shalt check the array bounds of all strings (indeed, all\narrays), for surely where thou typest 'foo' someone someday shall\ntype 'supercalifragilisticexpialidocious'.\n\nSymbolic links can often be a problem. If 'find' calls 'lstat' on\nsomething and discovers that it is a directory, it's normal for 'find'\nto recurse into it. Even if the 'chdir' system call is used\nimmediately, there is still a window of opportunity between the 'lstat'\nand the 'chdir' in which a malicious person could rename the directory\nand substitute a symbolic link to some other directory.\n", "subsections": [] }, "File: find-maint.info, Node: The File System Is Being Modified, Prev: Don't Trust the File System Contents, Up: Coding Conventions": { "content": "", "subsections": [ { "name": "4.5 The File System Is Being Modified", "content": "" } ] }, "The filesystem gets modified while you are traversing it. For, example,": { "content": "it's normal for files to get deleted while 'find' is traversing a\ndirectory. Issuing an error message seems helpful when a file is\ndeleted from the one directory you are interested in, but if 'find' is\nsearching 15000 directories, such a message becomes less helpful.\n\nBear in mind also that it is possible for the directory 'find' is\nsearching to be concurrently moved elsewhere in the file system, and\nthat the directory in which 'find' was started could be deleted.\n\nHenry Spencer's sixth commandment is also apposite here:\nIf a function be advertised to return an error code in the event of\ndifficulties, thou shalt check for that code, yea, even though the\nchecks triple the size of thy code and produce aches in thy typing\nfingers, for if thou thinkest \"it cannot happen to me\", the gods\nshall surely punish thee for thy arrogance.\n\nThere are a lot of files out there. They come in all dates and\nsizes. There is a condition out there in the real world to exercise\nevery bit of the code base. So we try to test that code base before\nsomeone falls over a bug.\n", "subsections": [] }, "File: find-maint.info, Node: Tools, Next: Using the GNU Portability Library, Prev: Coding Conventions, Up: Top": { "content": "", "subsections": [] }, "5 Tools": { "content": "", "subsections": [] }, "Most of the tools required to build findutils are mentioned in the file": { "content": "'README-hacking'. We also use some other tools:\n", "subsections": [] }, "System call traces": { "content": "Much of the execution time of find is spent waiting for filesystem\noperations. A system call trace (for example, that provided by\n'strace') shows what system calls are being made. Using this\ninformation we can work to remove unnecessary file system\noperations.\n", "subsections": [] }, "Valgrind": { "content": "Valgrind is a tool which dynamically verifies the memory accesses a\nprogram makes to ensure that they are valid (for example, that the\nbehaviour of the program does not in any way depend on the contents\nof uninitialized memory).\n", "subsections": [] }, "DejaGnu": { "content": "DejaGnu is the test framework used to run the findutils test suite\n(the 'runtest' program is part of DejaGnu). It would be ideal if\neverybody building 'findutils' also ran the test suite, but many\npeople don't have DejaGnu installed. When changes are made to\nfindutils, DejaGnu is invoked a lot. *Note Testing::, for more\ninformation.\n", "subsections": [] }, "File: find-maint.info, Node: Using the GNU Portability Library, Next: Documentation, Prev: Tools, Up: Top": { "content": "", "subsections": [] }, "6 Using the GNU Portability Library": { "content": "The Gnulib library () makes a\nvariety of systems look more like a GNU/Linux system and also applies a\nbunch of automatic bug fixes and workarounds. Some of these also apply\nto GNU/Linux systems too. For example, the Gnulib regex implementation\nis used when we determine that we are building on a GNU libc system with\na bug in the regex implementation.\n", "subsections": [ { "name": "6.1 How and Why we Import the Gnulib Code", "content": "" } ] }, "Gnulib does not have a release process which results in a source tarball": { "content": "you can download. Instead, the code is simply made available by GIT, so\nwe import gnulib via the submodule feature. The bootstrap script\nperforms the necessary steps.\n\nFindutils does not use all the Gnulib code. The modules we need are\nlisted in the file 'bootstrap.conf'.\n\nThe upshot of all this is that we can use the findutils git\nrepository to track which version of Gnulib every findutils release\nuses.\n\nA small number of files are installed by automake and will therefore\nvary according to which version of automake was used to generate a\nrelease. This includes for example boiler-plate GNU files such as\n'ABOUT-NLS', 'INSTALL' and 'COPYING'.\n", "subsections": [ { "name": "6.2 How We Fix Gnulib Bugs", "content": "" } ] }, "Gnulib is used by quite a number of GNU projects, and this means that it": { "content": "gets plenty of testing. Therefore there are relatively few bugs in the\nGnulib code, but it does happen from time to time.\n\nHowever, since there is no waiting around for a Gnulib source release\ntarball, Gnulib bugs are generally fixed quickly. Here is an outline of\nthe way we would contribute a fix to Gnulib (assuming you know it is not\nalready fixed in the current Gnulib git tree):\n", "subsections": [] }, "Check you already completed a copyright assignment for Gnulib": { "content": "", "subsections": [] }, "Begin with a vanilla git tree": { "content": "Download the Findutils source code from git (or use the tree you\nhave already)", "subsections": [] }, "Run the bootstrap script": { "content": "", "subsections": [] }, "Run configure": { "content": "", "subsections": [] }, "Build findutils": { "content": "Build findutils and run the test suite, which should pass. In our\nexample we assume you have just noticed a bug in Gnulib, not that\nrecent Gnulib changes broke the findutils regression tests.", "subsections": [] }, "Write a test case": { "content": "If in fact Gnulib did break the findutils regression tests, you can\nprobably skip this step, since you already have a test case\ndemonstrating the problem. Otherwise, write a findutils test case\nfor the bug and/or a Gnulib test case.", "subsections": [] }, "Fix the Gnulib bug": { "content": "Make sure your editor follows symbolic links so that your changes\nto 'gnulib/...' actually affect the files in the git working\ndirectory you checked out earlier. Observe that your test now\npasses.", "subsections": [] }, "Prepare a Gnulib patch": { "content": "In the gnulib subdirectory, use 'git format-patch' to prepare the\npatch. Follow the normal usage for checkin comments (take a look\nat the output of 'git log'). Check that the patch conforms with\nthe GNU coding standards, and email it to the Gnulib mailing list.", "subsections": [] }, "Wait for the patch to be applied": { "content": "Once your bug fix has been applied, you can update your gnulib\ndirectory from git, and then check in the change to the submodule\nas normal (you can check 'git help submodule' for details).\n\nThere is an alternative to the method above; it is possible to store\nlocal diffs to be patched into gnulib beneath the 'gnulib-local'.", "subsections": [] }, "Normally however, there is no need for this, since gnulib updates are": { "content": "very prompt.\n", "subsections": [ { "name": "6.3 How to update Gnulib to latest", "content": "" } ] }, "With a non-dirty working tree, the command 'make": { "content": "update-gnulib-to-latest' (or the shorter alias 'make gnulib-sync'\nallows, well, to update the gnulib submodule. In detail, that is:\n1. Fetching the latest upstream gnulib reference.\n2. Copying the files which should stay in sync like 'bootstrap' from\ngnulib into the findutils working tree.\n3. And finally showing the 'git status' for the gnulib submodule and\nthe above copied files.\nAfter that, the maintainer compares if all is correct, if the\nfindutils build and run correct, and finally commits with the new gnulib\nversion, e.g. via 'git gui'.\n\nThe 'gnulib-sync' target can be run any time - after a 'configure'\nrun -, and only rejects to run if the working tree is dirty.\n", "subsections": [] }, "File: find-maint.info, Node: Documentation, Next: Testing, Prev: Using the GNU Portability Library, Up: Top": { "content": "", "subsections": [] }, "7 Documentation": { "content": "", "subsections": [] }, "The findutils git tree includes several different types of": { "content": "documentation.\n", "subsections": [ { "name": "7.1 git change log", "content": "" } ] }, "The git change log for the source tree contains check-in messages which": { "content": "describe each check-in. These have a standard format:\n\nSummary of the change.\n\n(ChangeLog-style detail)\n\nHere, the format of the detail part follows the standard GNU", "subsections": [] }, "ChangeLog style, but without whitespace in the left margin and without": { "content": "author/date headers. Take a look at the output of 'git log' to see some\nexamples. The README-hacking file also contains an example with an\nexplanation.\n", "subsections": [ { "name": "7.2 User Documentation", "content": "User-oriented documentation is provided as manual pages and in Texinfo.\nSee *note Introduction: (find)Introduction.\n\nPlease make sure both sets of documentation are updated if you make a\nchange to the code. The GNU coding standards do not normally call for\nmaintaining manual pages on the grounds of effort duplication. However,\nthe manual page format is more convenient for quick reference, and so\nit's worth maintaining both types of documentation. However, the manual\npages are normally rather more terse than the Texinfo documentation." } ] }, "The manual pages are suitable for reference use, but the Texinfo manual": { "content": "should also include introductory and tutorial material.\n\nWe make the user documentation available on the web, on the GNU\nproject web site. These web pages are source-controlled via CVS\n(still!). If you are a member of the 'findutils' project on Savannah\nyou should be able to check the web pages out like this ('$USER' is a\nplaceholder for your Savannah username):\n\ncvs -d :ext:$USER@cvs.savannah.gnu.org:/web/findutils checkout findutils/manual\n\nYou can automatically update the documentation in this repository\nusing the script 'build-aux/update-online-manual.sh' in the findutils\nGit repository.\n", "subsections": [ { "name": "7.3 Build Guidance", "content": "'ABOUT-NLS'\nDescribes the Free Translation Project, the translation status of\nvarious GNU projects, and how to participate by translating an\napplication.\n'AUTHORS'\nLists the authors of findutils.\n'COPYING'\nThe copyright license covering findutils; currently, the GNU GPL,\nversion 3.\n'INSTALL'\nGeneric installation instructions for installing GNU programs.\n'README'\nInformation about how to compile findutils in particular\n'README-hacking'\nDescribes how to build findutils from the code in git.\n'THANKS'\nThanks for people who contributed to findutils. Generally, if\nsomeone's contribution was significant enough to need a copyright\nassignment, their name should go in here.\n'TODO'\nMainly obsolete. Please add bugs to the Savannah bug tracker\ninstead of adding entries to this file.\n" }, { "name": "7.4 Release Information", "content": "'NEWS'\nEnumerates the user-visible change in each release. Typical\nchanges are fixed bugs, functionality changes and documentation\nchanges. Include the date when a release is made.\n'ChangeLog'\nThis file enumerates all changes to the findutils source code (with\nthe possible exception of '.cvsignore' and '.gitignore' changes).\nThe level of detail used for this file should be sufficient to\nanswer the questions \"what changed?\" and \"why was it changed?\".\nThe file is generated from the git commit messages during 'make\ndist'. If a change fixes a bug, always give the bug reference\nnumber in the 'NEWS' file and of course also in the checkin\nmessage. In general, it should be possible to enumerate all\nmaterial changes to a function by searching for its name in\n'ChangeLog'. Mention when each release is made.\n" } ] }, "File: find-maint.info, Node: Testing, Next: Bugs, Prev: Documentation, Up: Top": { "content": "", "subsections": [] }, "8 Testing": { "content": "", "subsections": [] }, "This chapter will explain the general procedures for adding tests to the": { "content": "test suite, and the functions defined in the findutils-specific DejaGnu\nconfiguration. Where appropriate references will be made to the DejaGnu\ndocumentation.\n", "subsections": [] }, "File: find-maint.info, Node: Bugs, Next: Distributions, Prev: Testing, Up: Top": { "content": "", "subsections": [] }, "9 Bugs": { "content": "", "subsections": [] }, "Bugs are logged in the Savannah bug tracker": { "content": ". The tracker offers\nseveral fields but their use is largely obvious. The life-cycle of a\nbug is like this:\n", "subsections": [] }, "Open": { "content": "Someone, usually a maintainer, a distribution maintainer or a user,\ncreates a bug by filling in the form. They fill in field values as\nthey see fit. This will generate an email to\n.\n", "subsections": [] }, "Triage": { "content": "The bug hangs around with 'Status=None' until someone begins to\nwork on it. At that point they set the \"Assigned To\" field and\nwill sometimes set the status to 'In Progress', especially if the\nbug will take a while to fix.\n", "subsections": [] }, "Non-bugs": { "content": "Quite a lot of reports are not actually bugs; for these the usual\nprocedure is to explain why the problem is not a bug, set the\nstatus to 'Invalid' and close the bug. Make sure you set the\n'Assigned to' field to yourself before closing the bug.\n", "subsections": [] }, "Fixing": { "content": "When you commit a bug fix into git (or in the case of a contributed\npatch, commit the change), mark the bug as 'Fixed'. Make sure you\ninclude a new test case where this is relevant. If you can figure\nout which releases are affected, please also set the 'Release'\nfield to the earliest release which is affected by the bug.\nIndicate which source branch the fix is included in (for example,\n4.2.x or 4.3.x). Don't close the bug yet.\n", "subsections": [] }, "Release": { "content": "When a release is made which includes the bug fix, make sure the\nbug is listed in the NEWS file. Once the release is made, fill in\nthe 'Fixed Release' field and close the bug.\n", "subsections": [] }, "File: find-maint.info, Node: Distributions, Next: Internationalisation, Prev: Bugs, Up: Top": { "content": "", "subsections": [] }, "10 Distributions": { "content": "", "subsections": [] }, "Almost all GNU/Linux distributions include findutils, but only some of": { "content": "them have a package maintainer who is a member of the mailing list.", "subsections": [] }, "Distributions don't often feed back patches to the": { "content": " list, but on the other hand many of their\npatches relate only to standards for file locations and so forth, and\nare therefore distribution specific. On an irregular basis I check the\ncurrent patches being used by one or two distributions, but the total\nnumber of GNU/Linux distributions is large enough that we could not hope\nto cover them all.\n\nOften, bugs are raised against a distribution's bug tracker instead\nof GNU's. Periodically (about every six months) I take a look at some\nof the more accessible bug trackers to indicate which bugs have been\nfixed upstream.\n\nMany distributions include both findutils and the slocate package,\nwhich provides a replacement 'locate'.\n", "subsections": [] }, "File: find-maint.info, Node: Internationalisation, Next: Security, Prev: Distributions, Up: Top": { "content": "", "subsections": [] }, "11 Internationalisation": { "content": "", "subsections": [] }, "Translation is essentially automated from the maintainer's point of": { "content": "view. The TP mails the maintainer when a new PO file is available, and\nwe just download it and check it in. The 'bootstrap' script copies\n'.po' files into the working tree. For more information, please see\n.\n", "subsections": [] }, "File: find-maint.info, Node: Security, Next: Making Releases, Prev: Internationalisation, Up: Top": { "content": "", "subsections": [] }, "12 Security": { "content": "See *note Security Considerations: (find)Security Considerations, for a\nfull description of the findutils approach to security considerations\nand discussion of particular tools.\n\nIf someone reports a security bug publicly, we should fix this as\nrapidly as possible. If necessary, this can mean issuing a fixed\nrelease containing just the one bug fix. We try to avoid issuing\nreleases which include both significant security fixes and functional\nchanges.\n\nWhere someone reports a security problem privately, we generally try\nto construct and test a patch without pushing the intermediate code to\nthe public repository.\n\nOnce everything has been tested, this allows us to make a release and\npush the patch. The advantage of doing things this way is that we avoid\nsituations where people watching for git commits can figure out and\nexploit a security problem before a fixed release is available.\n\nIt's important that security problems be fixed promptly, but don't\nrush so much that things go wrong. Make sure the new release really\nfixes the problem. It's usually best not to include functional changes\nin your security-fix release.\n\nIf the security problem is serious, send an alert to\n. The members of the list include most GNU/Linux\ndistributions. The point of doing this is to allow them to prepare to\nrelease your security fix to their customers, once the fix becomes\navailable. Here is an example alert:-\n\nGNU findutils heap buffer overrun (potential privilege escalation)\n\n\n", "subsections": [ { "name": "I. BACKGROUND", "content": "GNU findutils is a set of programs which search for files on Unix-like\nsystems. It is maintained by the GNU Project of the Free Software\nFoundation. For more information, see\n.\n\n" }, { "name": "II. DESCRIPTION", "content": "When GNU locate reads filenames from an old-format locate database,\nthey are read into a fixed-length buffer allocated on the heap.\nFilenames longer than the 1026-byte buffer can cause a buffer overrun.\nThe overrunning data can be chosen by any person able to control the\nnames of filenames created on the local system. This will normally\ninclude all local users, but in many cases also remote users (for\nexample in the case of FTP servers allowing uploads).\n" }, { "name": "III. ANALYSIS", "content": "Findutils supports three different formats of locate database, its\nnative format \"LOCATE02\", the slocate variant of LOCATE02, and a\ntraditional (\"old\") format that locate uses on other Unix systems.\n\nWhen locate reads filenames from a LOCATE02 database (the default\nformat), the buffer into which data is read is automatically extended\nto accommodate the length of the filenames.\n\nThis automatic buffer extension does not happen for old-format\ndatabases. Instead a 1026-byte buffer is used. When a longer\npathname appears in the locate database, the end of this buffer is\noverrun. The buffer is allocated on the heap (not the stack).\n\nIf the locate database is in the default LOCATE02 format, the locate\nprogram does perform automatic buffer extension, and the program is\nnot vulnerable to this problem. The software used to build the\nold-format locate database is not itself vulnerable to the same\nattack.\n\nMost installations of GNU findutils do not use the old database\nformat, and so will not be vulnerable.\n\n" }, { "name": "IV. DETECTION", "content": "All existing releases of findutils are affected.\n\n\n\nTo discover the longest path name on a given system, you can use the\nfollowing command (requires GNU findutils and GNU coreutils):\n\nfind / -print0 | tr -c '\\0' 'x' | tr '\\0' '\\n' | wc -L\n" }, { "name": "V. EXAMPLE", "content": "This section includes a shell script which determines which of a list\nof locate binaries is vulnerable to the problem. The shell script has\nbeen tested only on glibc based systems having a mktemp binary.\n\nNOTE: This script deliberately overruns the buffer in order to\ndetermine if a binary is affected. Therefore running it on your\nsystem may have undesirable effects. We recommend that you read the\nscript before running it.\n\n#! /bin/sh\nset +m\nif vanilladb=\"$(mktemp nicedb.XXXXXX)\" ; then\nif updatedb --prunepaths=\"\" --old-format --localpaths=\"/tmp\" \\\n--output=\"$@{vanilladb@}\" ; then\ntrue\nelse\nrm -f \"$@{vanilladb@}\"\nvanilladb=\"\"\necho \"Failed to create old-format locate database; skipping the sanity checks\" >&2\nfi\nfi\n\nmakeoverrundb() @{\n# Start with a valid database\ncat \"$@{vanilladb@}\"\n# Make the final entry really long\ndd if=/dev/zero bs=1 count=1500 2>/dev/null | tr '\\000' 'x'\n@}\n\n\n\nulimit -c 0\n\nusage() @{ echo \"usage: $0 binary [binary...]\" >&2; exit $1; @}\n[ $# -eq 0 ] && usage 1\n\nbad=\"\"\ngood=\"\"\nugly=\"\"\nif dbfile=\"$(mktemp nasty.XXXXXX)\"\nthen\nmakeoverrundb > \"$dbfile\"\nfor locate ; do\nver=\"$locate = $(\"$locate\" --version | head -1)\"\nif [ -z \"$vanilladb\" ] || \"$locate\" -d \"$vanilladb\" \"\" >/dev/null ; then\n\"$locate\" -d \"$dbfile\" \"\" >/dev/null\nif [ $? -gt 128 ] ; then\nbad=\"$bad\nvulnerable: $ver\"\nelse\ngood=\"$good\ngood: $ver\"\nfi\nelse\n# the regular locate failed\nugly=\"$ugly\nbuggy, may or may not be vulnerable: $ver\"\nfi\ndone\nrm -f \"$@{dbfile@}\" \"$@{vanilladb@}\"\n# good: unaffected. bad: affected (vulnerable).\n# ugly: doesn't even work for a normal old-format database.\necho \"$good\"\necho \"$bad\"\necho \"$ugly\"\nelse\nexit 1\nfi\n\n\n\n" }, { "name": "VI. VENDOR RESPONSE", "content": "The GNU project discovered the problem while 'locate' was being worked\non; this is the first public announcement of the problem.\n\nThe GNU findutils mantainer has issued a patch as p[art of this\nannouncement. The patch appears below.\n\nA source release of findutils-4.2.31 will be issued on 2007-05-30.\nThat release will of course include the patch. The patch will be\ncommitted to the public CVS repository at the same time. Public\nannouncements of the release, including a description of the bug, will\nbe made at the same time as the release.\n\nA release of findutils-4.3.x will follow and will also include the\npatch.\n\n" }, { "name": "VII. PATCH", "content": "This patch should apply to findutils-4.2.23 and later.\nFindutils-4.2.23 was released almost two years ago." }, { "name": "Index: locate/locate.c", "content": "RCS file: /cvsroot/findutils/findutils/locate/locate.c,v\nretrieving revision 1.58.2.2\ndiff -u -p -r1.58.2.2 locate.c\n--- locate/locate.c\t22 Apr 2007 16:57:42 -0000\t1.58.2.2\n+++ locate/locate.c\t28 May 2007 10:18:16 -0000\n@@@@ -124,9 +124,9 @@@@ extern int errno;\n\n#include \"locatedb.h\"\n#include \n-#include \"../gnulib/lib/xalloc.h\"\n-#include \"../gnulib/lib/error.h\"\n-#include \"../gnulib/lib/human.h\"\n+#include \"xalloc.h\"\n+#include \"error.h\"\n+#include \"human.h\"\n#include \"dirname.h\"\n#include \"closeout.h\"\n#include \"nextelem.h\"\n@@@@ -468,10 +468,36 @@@@ visitjustprintunquoted(struct process\nreturn VISITCONTINUE;\n@}\n\n+static void\n+toolong (struct processdata *procdata)\n+@{\n+ error (EXITFAILURE, 0,\n+\t (\"locate database %s contains a \"\n+\t \"filename longer than locate can handle\"),\n+\t procdata->dbfile);\n+@}\n+\n+static void\n+extend (struct processdata *procdata, sizet siz1, sizet siz2)\n+@{\n+ /* Figure out if the addition operation is safe before performing it. */\n+ if (SIZEMAX - siz1 < siz2)\n+ @{\n+ toolong (procdata);\n+ @}\n+ else if (procdata->pathsize < (siz1+siz2))\n+ @{\n+ procdata->pathsize = siz1+siz2;\n+ procdata->originalfilename = x2nrealloc (procdata->originalfilename,\n+\t\t\t\t\t\t&procdata->pathsize,\n+\t\t\t\t\t\t1);\n+ @}\n+@}\n+\nstatic int\nvisitoldformat(struct processdata *procdata, void *context)\n@{\n- register char *s;\n+ register sizet i;\n(void) context;\n\n/* Get the offset in the path where this path info starts. */\n@@@@ -479,20 +505,35 @@@@ visitoldformat(struct processdata *pr\nprocdata->count += getw (procdata->fp) - LOCATEDBOLDOFFSET;\nelse\nprocdata->count += procdata->c - LOCATEDBOLDOFFSET;\n+ assert(procdata->count > 0);\n\n- /* Overlay the old path with the remainder of the new. */\n- for (s = procdata->originalfilename + procdata->count;\n+ /* Overlay the old path with the remainder of the new. Read\n+ * more data until we get to the next filename.\n+ */\n+ for (i=procdata->count;\n(procdata->c = getc (procdata->fp)) > LOCATEDBOLDESCAPE;)\n- if (procdata->c < 0200)\n- *s++ = procdata->c;\t\t/* An ordinary character. */\n- else\n- @{\n-\t/* Bigram markers have the high bit set. */\n-\tprocdata->c &= 0177;\n-\t*s++ = procdata->bigram1[procdata->c];\n-\t*s++ = procdata->bigram2[procdata->c];\n- @}\n- *s-- = '\\0';\n+ @{\n+ if (procdata->c < 0200)\n+\t@{\n+\t /* An ordinary character. */\n+\t extend (procdata, i, 1u);\n+\t procdata->originalfilename[i++] = procdata->c;\n+\t@}\n+ else\n+\t@{\n+\t /* Bigram markers have the high bit set. */\n+\t extend (procdata, i, 2u);\n+\t procdata->c &= 0177;\n+\t procdata->originalfilename[i++] = procdata->bigram1[procdata->c];\n+\t procdata->originalfilename[i++] = procdata->bigram2[procdata->c];\n+\t@}\n+ @}\n+\n+ /* Consider the case where we executed the loop body zero times; we\n+ * still need space for the terminating null byte.\n+ */\n+ extend (procdata, i, 1u);\n+ procdata->originalfilename[i] = 0;\n\nprocdata->mungedfilename = procdata->originalfilename;\n\n" }, { "name": "VIII. THANKS", "content": "Thanks to Rob Holland and Tavis Ormandy.\n\n" }, { "name": "VIII. CVE INFORMATION", "content": "No CVE candidate number has yet been assigned for this vulnerability.\nIf someone provides one, I will include it in the public announcement\nand change logs.\n\nThe original announcement above was sent out with a cleartext PGP\nsignature, of course, but that has been omitted from the example.\n\nOnce a fixed release is available, announce the new release using the\nnormal channels. Any CVE number assigned for the problem should be\nincluded in the 'ChangeLog' and 'NEWS' entries. See\n for an explanation of CVE numbers.\n" } ] }, "File: find-maint.info, Node: Making Releases, Next: GNU Free Documentation License, Prev: Security, Up: Top": { "content": "", "subsections": [] }, "13 Making Releases": { "content": "", "subsections": [] }, "This section will explain how to make a findutils release. For the time": { "content": "being here is a terse description of the main steps:\n\n1. Commit changes; make sure your working directory has no uncommitted\nchanges.\n2. Update translation files; re-run bootstrap to download the newest\n'.po' files.\n3. Make sure compiler warnings would block the release; re-run\n'configure' with the options '--enable-compiler-warnings\n--enable-compiler-warnings-are-errors'.\n4. Test; make sure that all changes you have made have tests, and that\nthe tests pass. Verify this with 'env RUNEXPENSIVETESTS=yes make\ndistcheck'.\n5. Bugs; make sure all Savannah bug entries fixed in this release are\nmarked as fixed in Savannah. Optionally close them too to save\nduplicate work (otherwise, close them after the release is\nuploaded).\n6. Add new release in Savannah field values; see the 'Bugs > Edit\nField Values' menu item. Add a field value for the release you are\nabout to make so that users can report bugs in it.\n7. Update version; make sure that the NEWS file is updated with the\nnew release number (and checked in).\n8. Tag the release; findutils releases are tagged like this for\nexample: v4.5.5. You can create a tag with the a command like\nthis:\ngit tag -s -m \"Findutils release X.Y.Z\" vX.Y.Z\n9. Build the release tarball; do this with 'make distcheck'. Copy the\ntarball somewhere safe.\n10. Merge; if the release (and signed tag) were made on a local\nbranch, merge the branch to your local master.\n11. Push; push your master to origin/master.\n12. Push the new release tag; assuming that the name of your remote is\n'origin', this is:\ngit push origin tag vX.Y.Z\n13. Prepare the upload and upload it. You can do this with\nbuild-aux/gnupload --to ftp.gnu.org:findutils findutils-X.Y.Z.tar.xz\nUse 'alpha.gnu.org:findutils' for an alpha or beta release. *Note\nAutomated FTP Uploads: (maintain)Automated FTP Uploads, for\ndetailed upload instructions.\n14. Check the FTP upload worked; you can look for an email from the\nrobot or check the contents of the actual FTP site.\n15. Make a release announcement; include an extract from the NEWS file\nwhich explains what's changed. Announcements for test releases\nshould just go to . Announcements for\nstable releases should go to as well.\n16. Post-release administrativa: add a new dummy release header in\nNEWS:\n\n'* Major changes in release ?.?.?, YYYY-MM-DD'\n\nand update the 'oldNEWShash' in 'cfg.mk' with 'make\nupdate-NEWS-hash'. Commit both changes.\n17. Close bugs; any bugs recorded on Savannah which were fixed in this\nrelease should now be marked as closed if there were not already.\nUpdate the 'Fixed Release' field of these bugs appropriately and\nmake sure the 'Assigned to' field is populated.\n", "subsections": [] }, "File: find-maint.info, Node: GNU Free Documentation License, Prev: Making Releases, Up: Top": { "content": "", "subsections": [] }, "Appendix A GNU Free Documentation License": { "content": "Version 1.3, 3 November 2008\n\nCopyright (C) 2000, 2001, 2002, 2007, 2008 Free Software Foundation, Inc.\n\n\nEveryone is permitted to copy and distribute verbatim copies\nof this license document, but changing it is not allowed.\n\n0. PREAMBLE\n\nThe purpose of this License is to make a manual, textbook, or other\nfunctional and useful document \"free\" in the sense of freedom: to\nassure everyone the effective freedom to copy and redistribute it,\nwith or without modifying it, either commercially or\nnoncommercially. Secondarily, this License preserves for the\nauthor and publisher a way to get credit for their work, while not\nbeing considered responsible for modifications made by others.\n\nThis License is a kind of \"copyleft\", which means that derivative\nworks of the document must themselves be free in the same sense.\nIt complements the GNU General Public License, which is a copyleft\nlicense designed for free software.\n\nWe have designed this License in order to use it for manuals for\nfree software, because free software needs free documentation: a\nfree program should come with manuals providing the same freedoms\nthat the software does. But this License is not limited to\nsoftware manuals; it can be used for any textual work, regardless\nof subject matter or whether it is published as a printed book. We\nrecommend this License principally for works whose purpose is\ninstruction or reference.\n\n1. APPLICABILITY AND DEFINITIONS\n\nThis License applies to any manual or other work, in any medium,\nthat contains a notice placed by the copyright holder saying it can\nbe distributed under the terms of this License. Such a notice\ngrants a world-wide, royalty-free license, unlimited in duration,\nto use that work under the conditions stated herein. The\n\"Document\", below, refers to any such manual or work. Any member\nof the public is a licensee, and is addressed as \"you\". You accept\nthe license if you copy, modify or distribute the work in a way\nrequiring permission under copyright law.\n\nA \"Modified Version\" of the Document means any work containing the\nDocument or a portion of it, either copied verbatim, or with\nmodifications and/or translated into another language.\n\nA \"Secondary Section\" is a named appendix or a front-matter section\nof the Document that deals exclusively with the relationship of the\npublishers or authors of the Document to the Document's overall\nsubject (or to related matters) and contains nothing that could\nfall directly within that overall subject. (Thus, if the Document\nis in part a textbook of mathematics, a Secondary Section may not\nexplain any mathematics.) The relationship could be a matter of\nhistorical connection with the subject or with related matters, or\nof legal, commercial, philosophical, ethical or political position\nregarding them.\n\nThe \"Invariant Sections\" are certain Secondary Sections whose\ntitles are designated, as being those of Invariant Sections, in the\nnotice that says that the Document is released under this License.\nIf a section does not fit the above definition of Secondary then it\nis not allowed to be designated as Invariant. The Document may\ncontain zero Invariant Sections. If the Document does not identify\nany Invariant Sections then there are none.\n\nThe \"Cover Texts\" are certain short passages of text that are\nlisted, as Front-Cover Texts or Back-Cover Texts, in the notice\nthat says that the Document is released under this License. A\nFront-Cover Text may be at most 5 words, and a Back-Cover Text may\nbe at most 25 words.\n\nA \"Transparent\" copy of the Document means a machine-readable copy,\nrepresented in a format whose specification is available to the\ngeneral public, that is suitable for revising the document\nstraightforwardly with generic text editors or (for images composed\nof pixels) generic paint programs or (for drawings) some widely\navailable drawing editor, and that is suitable for input to text\nformatters or for automatic translation to a variety of formats\nsuitable for input to text formatters. A copy made in an otherwise\nTransparent file format whose markup, or absence of markup, has\nbeen arranged to thwart or discourage subsequent modification by\nreaders is not Transparent. An image format is not Transparent if\nused for any substantial amount of text. A copy that is not\n\"Transparent\" is called \"Opaque\".\n\nExamples of suitable formats for Transparent copies include plain\nASCII without markup, Texinfo input format, LaTeX input format,\nSGML or XML using a publicly available DTD, and standard-conforming\nsimple HTML, PostScript or PDF designed for human modification.\nExamples of transparent image formats include PNG, XCF and JPG.\nOpaque formats include proprietary formats that can be read and\nedited only by proprietary word processors, SGML or XML for which\nthe DTD and/or processing tools are not generally available, and\nthe machine-generated HTML, PostScript or PDF produced by some word\nprocessors for output purposes only.\n\nThe \"Title Page\" means, for a printed book, the title page itself,\nplus such following pages as are needed to hold, legibly, the\nmaterial this License requires to appear in the title page. For\nworks in formats which do not have any title page as such, \"Title\nPage\" means the text near the most prominent appearance of the\nwork's title, preceding the beginning of the body of the text.\n\nThe \"publisher\" means any person or entity that distributes copies\nof the Document to the public.\n\nA section \"Entitled XYZ\" means a named subunit of the Document\nwhose title either is precisely XYZ or contains XYZ in parentheses\nfollowing text that translates XYZ in another language. (Here XYZ\nstands for a specific section name mentioned below, such as\n\"Acknowledgements\", \"Dedications\", \"Endorsements\", or \"History\".)\nTo \"Preserve the Title\" of such a section when you modify the\nDocument means that it remains a section \"Entitled XYZ\" according\nto this definition.\n\nThe Document may include Warranty Disclaimers next to the notice\nwhich states that this License applies to the Document. These\nWarranty Disclaimers are considered to be included by reference in\nthis License, but only as regards disclaiming warranties: any other\nimplication that these Warranty Disclaimers may have is void and\nhas no effect on the meaning of this License.\n\n2. VERBATIM COPYING\n\nYou may copy and distribute the Document in any medium, either\ncommercially or noncommercially, provided that this License, the\ncopyright notices, and the license notice saying this License\napplies to the Document are reproduced in all copies, and that you\nadd no other conditions whatsoever to those of this License. You\nmay not use technical measures to obstruct or control the reading\nor further copying of the copies you make or distribute. However,\nyou may accept compensation in exchange for copies. If you\ndistribute a large enough number of copies you must also follow the\nconditions in section 3.\n\nYou may also lend copies, under the same conditions stated above,\nand you may publicly display copies.\n\n3. COPYING IN QUANTITY\n\nIf you publish printed copies (or copies in media that commonly\nhave printed covers) of the Document, numbering more than 100, and\nthe Document's license notice requires Cover Texts, you must\nenclose the copies in covers that carry, clearly and legibly, all\nthese Cover Texts: Front-Cover Texts on the front cover, and\nBack-Cover Texts on the back cover. Both covers must also clearly\nand legibly identify you as the publisher of these copies. The\nfront cover must present the full title with all words of the title\nequally prominent and visible. You may add other material on the\ncovers in addition. Copying with changes limited to the covers, as\nlong as they preserve the title of the Document and satisfy these\nconditions, can be treated as verbatim copying in other respects.\n\nIf the required texts for either cover are too voluminous to fit\nlegibly, you should put the first ones listed (as many as fit\nreasonably) on the actual cover, and continue the rest onto\nadjacent pages.\n\nIf you publish or distribute Opaque copies of the Document\nnumbering more than 100, you must either include a machine-readable\nTransparent copy along with each Opaque copy, or state in or with\neach Opaque copy a computer-network location from which the general\nnetwork-using public has access to download using public-standard\nnetwork protocols a complete Transparent copy of the Document, free\nof added material. If you use the latter option, you must take\nreasonably prudent steps, when you begin distribution of Opaque\ncopies in quantity, to ensure that this Transparent copy will\nremain thus accessible at the stated location until at least one\nyear after the last time you distribute an Opaque copy (directly or\nthrough your agents or retailers) of that edition to the public.\n\nIt is requested, but not required, that you contact the authors of\nthe Document well before redistributing any large number of copies,\nto give them a chance to provide you with an updated version of the\nDocument.\n\n4. MODIFICATIONS\n\nYou may copy and distribute a Modified Version of the Document\nunder the conditions of sections 2 and 3 above, provided that you\nrelease the Modified Version under precisely this License, with the\nModified Version filling the role of the Document, thus licensing\ndistribution and modification of the Modified Version to whoever\npossesses a copy of it. In addition, you must do these things in\nthe Modified Version:\n\nA. Use in the Title Page (and on the covers, if any) a title\ndistinct from that of the Document, and from those of previous\nversions (which should, if there were any, be listed in the\nHistory section of the Document). You may use the same title\nas a previous version if the original publisher of that\nversion gives permission.\n\nB. List on the Title Page, as authors, one or more persons or\nentities responsible for authorship of the modifications in\nthe Modified Version, together with at least five of the\nprincipal authors of the Document (all of its principal\nauthors, if it has fewer than five), unless they release you\nfrom this requirement.\n\nC. State on the Title page the name of the publisher of the\nModified Version, as the publisher.\n\nD. Preserve all the copyright notices of the Document.\n\nE. Add an appropriate copyright notice for your modifications\nadjacent to the other copyright notices.\n\nF. Include, immediately after the copyright notices, a license\nnotice giving the public permission to use the Modified\nVersion under the terms of this License, in the form shown in\nthe Addendum below.\n\nG. Preserve in that license notice the full lists of Invariant\nSections and required Cover Texts given in the Document's\nlicense notice.\n\nH. Include an unaltered copy of this License.\n\nI. Preserve the section Entitled \"History\", Preserve its Title,\nand add to it an item stating at least the title, year, new\nauthors, and publisher of the Modified Version as given on the\nTitle Page. If there is no section Entitled \"History\" in the\nDocument, create one stating the title, year, authors, and\npublisher of the Document as given on its Title Page, then add\nan item describing the Modified Version as stated in the\nprevious sentence.\n\nJ. Preserve the network location, if any, given in the Document\nfor public access to a Transparent copy of the Document, and\nlikewise the network locations given in the Document for\nprevious versions it was based on. These may be placed in the\n\"History\" section. You may omit a network location for a work\nthat was published at least four years before the Document\nitself, or if the original publisher of the version it refers\nto gives permission.\n\nK. For any section Entitled \"Acknowledgements\" or \"Dedications\",\nPreserve the Title of the section, and preserve in the section\nall the substance and tone of each of the contributor\nacknowledgements and/or dedications given therein.\n\nL. Preserve all the Invariant Sections of the Document, unaltered\nin their text and in their titles. Section numbers or the\nequivalent are not considered part of the section titles.\n\nM. Delete any section Entitled \"Endorsements\". Such a section\nmay not be included in the Modified Version.\n\nN. Do not retitle any existing section to be Entitled\n\"Endorsements\" or to conflict in title with any Invariant\nSection.\n\nO. Preserve any Warranty Disclaimers.\n\nIf the Modified Version includes new front-matter sections or\nappendices that qualify as Secondary Sections and contain no\nmaterial copied from the Document, you may at your option designate\nsome or all of these sections as invariant. To do this, add their\ntitles to the list of Invariant Sections in the Modified Version's\nlicense notice. These titles must be distinct from any other\nsection titles.\n\nYou may add a section Entitled \"Endorsements\", provided it contains\nnothing but endorsements of your Modified Version by various\nparties--for example, statements of peer review or that the text\nhas been approved by an organization as the authoritative\ndefinition of a standard.\n\nYou may add a passage of up to five words as a Front-Cover Text,\nand a passage of up to 25 words as a Back-Cover Text, to the end of\nthe list of Cover Texts in the Modified Version. Only one passage\nof Front-Cover Text and one of Back-Cover Text may be added by (or\nthrough arrangements made by) any one entity. If the Document\nalready includes a cover text for the same cover, previously added\nby you or by arrangement made by the same entity you are acting on\nbehalf of, you may not add another; but you may replace the old\none, on explicit permission from the previous publisher that added\nthe old one.\n\nThe author(s) and publisher(s) of the Document do not by this\nLicense give permission to use their names for publicity for or to\nassert or imply endorsement of any Modified Version.\n\n5. COMBINING DOCUMENTS\n\nYou may combine the Document with other documents released under\nthis License, under the terms defined in section 4 above for\nmodified versions, provided that you include in the combination all\nof the Invariant Sections of all of the original documents,\nunmodified, and list them all as Invariant Sections of your\ncombined work in its license notice, and that you preserve all\ntheir Warranty Disclaimers.\n\nThe combined work need only contain one copy of this License, and\nmultiple identical Invariant Sections may be replaced with a single\ncopy. If there are multiple Invariant Sections with the same name\nbut different contents, make the title of each such section unique\nby adding at the end of it, in parentheses, the name of the\noriginal author or publisher of that section if known, or else a\nunique number. Make the same adjustment to the section titles in\nthe list of Invariant Sections in the license notice of the\ncombined work.\n\nIn the combination, you must combine any sections Entitled\n\"History\" in the various original documents, forming one section\nEntitled \"History\"; likewise combine any sections Entitled\n\"Acknowledgements\", and any sections Entitled \"Dedications\". You\nmust delete all sections Entitled \"Endorsements.\"\n\n6. COLLECTIONS OF DOCUMENTS\n\nYou may make a collection consisting of the Document and other\ndocuments released under this License, and replace the individual\ncopies of this License in the various documents with a single copy\nthat is included in the collection, provided that you follow the\nrules of this License for verbatim copying of each of the documents\nin all other respects.\n\nYou may extract a single document from such a collection, and\ndistribute it individually under this License, provided you insert\na copy of this License into the extracted document, and follow this\nLicense in all other respects regarding verbatim copying of that\ndocument.\n\n7. AGGREGATION WITH INDEPENDENT WORKS\n\nA compilation of the Document or its derivatives with other\nseparate and independent documents or works, in or on a volume of a\nstorage or distribution medium, is called an \"aggregate\" if the\ncopyright resulting from the compilation is not used to limit the\nlegal rights of the compilation's users beyond what the individual\nworks permit. When the Document is included in an aggregate, this\nLicense does not apply to the other works in the aggregate which\nare not themselves derivative works of the Document.\n\nIf the Cover Text requirement of section 3 is applicable to these\ncopies of the Document, then if the Document is less than one half\nof the entire aggregate, the Document's Cover Texts may be placed\non covers that bracket the Document within the aggregate, or the\nelectronic equivalent of covers if the Document is in electronic\nform. Otherwise they must appear on printed covers that bracket\nthe whole aggregate.\n\n8. TRANSLATION\n\nTranslation is considered a kind of modification, so you may\ndistribute translations of the Document under the terms of section\n4. Replacing Invariant Sections with translations requires special\npermission from their copyright holders, but you may include\ntranslations of some or all Invariant Sections in addition to the\noriginal versions of these Invariant Sections. You may include a\ntranslation of this License, and all the license notices in the\nDocument, and any Warranty Disclaimers, provided that you also\ninclude the original English version of this License and the\noriginal versions of those notices and disclaimers. In case of a\ndisagreement between the translation and the original version of\nthis License or a notice or disclaimer, the original version will\nprevail.\n\nIf a section in the Document is Entitled \"Acknowledgements\",\n\"Dedications\", or \"History\", the requirement (section 4) to\nPreserve its Title (section 1) will typically require changing the\nactual title.\n\n9. TERMINATION\n\nYou may not copy, modify, sublicense, or distribute the Document\nexcept as expressly provided under this License. Any attempt\notherwise to copy, modify, sublicense, or distribute it is void,\nand will automatically terminate your rights under this License.\n\nHowever, if you cease all violation of this License, then your\nlicense from a particular copyright holder is reinstated (a)\nprovisionally, unless and until the copyright holder explicitly and\nfinally terminates your license, and (b) permanently, if the\ncopyright holder fails to notify you of the violation by some\nreasonable means prior to 60 days after the cessation.\n\nMoreover, your license from a particular copyright holder is\nreinstated permanently if the copyright holder notifies you of the\nviolation by some reasonable means, this is the first time you have\nreceived notice of violation of this License (for any work) from\nthat copyright holder, and you cure the violation prior to 30 days\nafter your receipt of the notice.\n\nTermination of your rights under this section does not terminate\nthe licenses of parties who have received copies or rights from you\nunder this License. If your rights have been terminated and not\npermanently reinstated, receipt of a copy of some or all of the\nsame material does not give you any rights to use it.\n\n10. FUTURE REVISIONS OF THIS LICENSE\n\nThe Free Software Foundation may publish new, revised versions of\nthe GNU Free Documentation License from time to time. Such new\nversions will be similar in spirit to the present version, but may\ndiffer in detail to address new problems or concerns. See\n.\n\nEach version of the License is given a distinguishing version\nnumber. If the Document specifies that a particular numbered\nversion of this License \"or any later version\" applies to it, you\nhave the option of following the terms and conditions either of\nthat specified version or of any later version that has been\npublished (not as a draft) by the Free Software Foundation. If the\nDocument does not specify a version number of this License, you may\nchoose any version ever published (not as a draft) by the Free\nSoftware Foundation. If the Document specifies that a proxy can\ndecide which future versions of this License can be used, that\nproxy's public statement of acceptance of a version permanently\nauthorizes you to choose that version for the Document.\n\n11. RELICENSING\n\n\"Massive Multiauthor Collaboration Site\" (or \"MMC Site\") means any\nWorld Wide Web server that publishes copyrightable works and also\nprovides prominent facilities for anybody to edit those works. A\npublic wiki that anybody can edit is an example of such a server.\nA \"Massive Multiauthor Collaboration\" (or \"MMC\") contained in the\nsite means any set of copyrightable works thus published on the MMC\nsite.\n\n\"CC-BY-SA\" means the Creative Commons Attribution-Share Alike 3.0\nlicense published by Creative Commons Corporation, a not-for-profit\ncorporation with a principal place of business in San Francisco,\nCalifornia, as well as future copyleft versions of that license\npublished by that same organization.\n\n\"Incorporate\" means to publish or republish a Document, in whole or\nin part, as part of another Document.\n\nAn MMC is \"eligible for relicensing\" if it is licensed under this\nLicense, and if all works that were first published under this\nLicense somewhere other than this MMC, and subsequently\nincorporated in whole or in part into the MMC, (1) had no cover\ntexts or invariant sections, and (2) were thus incorporated prior\nto November 1, 2008.\n\nThe operator of an MMC Site may republish an MMC contained in the\nsite under CC-BY-SA on the same site at any time before August 1,\n2009, provided the MMC is eligible for relicensing.\n", "subsections": [ { "name": "ADDENDUM: How to use this License for your documents", "content": "" } ] }, "To use this License in a document you have written, include a copy of": { "content": "the License in the document and put the following copyright and license\nnotices just after the title page:\n\nCopyright (C) YEAR YOUR NAME.\nPermission is granted to copy, distribute and/or modify this document\nunder the terms of the GNU Free Documentation License, Version 1.3\nor any later version published by the Free Software Foundation;\nwith no Invariant Sections, no Front-Cover Texts, and no Back-Cover\nTexts. A copy of the license is included in the section entitled ``GNU\nFree Documentation License''.\n\nIf you have Invariant Sections, Front-Cover Texts and Back-Cover\nTexts, replace the \"with...Texts.\" line with this:\n\nwith the Invariant Sections being LIST THEIR TITLES, with\nthe Front-Cover Texts being LIST, and with the Back-Cover Texts\nbeing LIST.\n\nIf you have Invariant Sections without Cover Texts, or some other\ncombination of the three, merge those two alternatives to suit the\nsituation.\n\nIf your document contains nontrivial examples of program code, we\nrecommend releasing these examples in parallel under your choice of free\nsoftware license, such as the GNU General Public License, to permit\ntheir use in free software.\n\n", "subsections": [] } }, "flags": [], "examples": [], "see_also": [] }