[tor-commits] [tor/master] Move hacking documentation into a new subdirectory.
nickm at torproject.org
nickm at torproject.org
Fri Oct 9 14:40:57 UTC 2015
commit c751e5af4a87e9511f2c47725152d4a4ccb171b6
Author: Nick Mathewson <nickm at torproject.org>
Date: Fri Oct 9 09:28:24 2015 -0400
Move hacking documentation into a new subdirectory.
---
README | 2 +-
doc/GettingStarted.txt | 207 -------------
doc/HACKING | 662 ----------------------------------------
doc/HACKING/GettingStarted.txt | 207 +++++++++++++
doc/HACKING/HACKING_old | 662 ++++++++++++++++++++++++++++++++++++++++
doc/HACKING/WritingTests.txt | 401 ++++++++++++++++++++++++
doc/WritingTests.txt | 401 ------------------------
doc/include.am | 7 +-
8 files changed, 1275 insertions(+), 1274 deletions(-)
diff --git a/README b/README
index 342376f..d246a69 100644
--- a/README
+++ b/README
@@ -26,4 +26,4 @@ Frequently Asked Questions:
To get started working on Tor development:
- See the doc/HACKING file.
+ See the doc/HACKING directory.
diff --git a/doc/GettingStarted.txt b/doc/GettingStarted.txt
deleted file mode 100644
index 1f4b434..0000000
--- a/doc/GettingStarted.txt
+++ /dev/null
@@ -1,207 +0,0 @@
-
-
-(DRAFT)
-
-
-
-Getting started in Tor development
-==================================
-
-Congratulations! You've found this file, and you're reading it! This
-means that you might be interested in getting started in developing Tor.
-
-(This guide is just about Tor itself--the small network program at the
-heart of the Tor network--and not about all the other programs in the
-whole Tor ecosystem.)
-
-
-If you are looking for a more bare-bones, less user-friendly information
-dump of important information, you might like reading doc/HACKING
-instead. You should probably read it before you write your first patch.
-
-
-Required background
--------------------
-
-First, I'm going to assume that you can build Tor from source, and that
-you know enough of the C language to read and write it. (See the README
-file that comes with the Tor source for more information on building it,
-and any high-quality guide to C for information on programming.)
-
-I'm also going to assume that you know a little bit about how to use
-Git, or that you're able to fillow one of the several excellent guides
-at http://git-scm.org to learn.
-
-Most Tor developers develop using some Unix-based system, such as Linux,
-BSD, or OSX. It's okay to develop on Windows if you want, but you're
-going to have a more difficult time.
-
-
-Getting your first patch into Tor
----------------------------------
-
-Once you've reached this point, here's what you need to know.
-
- 1) Get the source.
-
- We keep our source under version control in Git. To get the latest
- version, run
- git clone https://git.torproject.org/git/tor
-
- This will give you a checkout of the master branch. If you're
- going to fix a bug that appears in a stable version, check out the
- appropriate "maint" branch, as in:
-
- git checkout maint-0.2.7
-
- 2) Find your way around the source
-
- Our overall code structure is explained in the "torguts" documents,
- currently at
- git clone https://git.torproject.org/user/nickm/torguts.git
-
- Find a part of the code that looks interesting to you, and start
- looking around it to see how it fits together!
-
- We do some unusual things in our codebase. Our testing-related
- practices and kludges are explained in doc/WritingTests.txt.
-
- If you see something that doesn't make sense, we love to get
- questions!
-
- 3) Find something cool to hack on.
-
- You may already have a good idea of what you'd like to work on, or
- you might be looking for a way to contribute.
-
- Many people have gotten started by looking for an area where they
- personally felt Tor was underperforming, and investigating ways to
- fix it. If you're looking for ideas, you can head to our bug
- tracker at trac.torproject.org and look for tickets that have
- received the "easy" tag: these are ones that developers think would
- be pretty simple for a new person to work on. For a bigger
- challenge, you might want to look for tickets with the "lorax"
- keyword: these are tickets that the developers think might be a
- good idea to build, but which we have no time to work on any time
- soon.
-
- Or you might find another open ticket that piques your
- interest. It's all fine!
-
- For your first patch, it is probably NOT a good idea to make
- something huge or invasive. In particular, you should probably
- avoid:
- * Major changes spread across many parts of the codebase.
- * Major changes to programming practice or coding style.
- * Huge new features or protocol changes.
-
- 4) Meet the developers!
-
- We discuss stuff on the tor-dev mailing list and on the #tor-dev
- IRC channel on OFTC. We're generally friendly and approachable,
- and we like to talk about how Tor fits together. If we have ideas
- about how something should be implemented, we'll be happy to share
- them.
-
- We currently have a patch workshop at least once a week, where
- people share patches they've made and discuss how to make them
- better. The time might change in the future, but generally,
- there's no bad time to talk, and ask us about patch ideas.
-
- 5) Do you need to write a design proposal?
-
- If your idea is very large, or it will require a change to Tor's
- protocols, there needs to be a written design proposal before it
- can be merged. (We use this process to manage changes in the
- protocols.) To write one, see the instructions at
- https://gitweb.torproject.org/torspec.git/tree/proposals/001-process.txt
- . If you'd like help writing a proposal, just ask! We're happy to
- help out with good ideas.
-
- You might also like to look around the rest of that directory, to
- see more about open and past proposed changes to Tor's behavior.
-
- 6) Writing your patch
-
- As you write your code, you'll probably want it to fit in with the
- standards of the rest of the Tor codebase so it will be easy for us
- to review and merge. You can learn our coding standards in
- doc/HACKING.
-
- If your patch is large and/or is divided into multiple logical
- components, remember to divide it into a series of Git commits. A
- series of small changes is much easier to review than one big lump.
-
- 7) Testing your patch
-
- We prefer that all new or modified code have unit tests for it to
- ensure that it runs correctly. Also, all code should actually be
- _run_ by somebody, to make sure it works.
-
- See doc/WritingTests.txt for more information on how we test things
- in Tor. If you'd like any help writing tests, just ask! We're
- glad to help out.
-
- 8) Submitting your patch
-
- We review patches through tickets on our bugtracker at
- trac.torproject.org. You can either upload your patches there, or
- put them at a public git repository somewhere we can fetch them
- (like github or bitbucket) and then paste a link on the appropriate
- trac ticket.
-
- Once your patches are available, write a short explanation of what
- you've done on trac, and then change the status of the ticket to
- needs_review.
-
- 9) Review, Revision, and Merge
-
- With any luck, somebody will review your patch soon! If not, you
- can ask on the IRC channel; sometimes we get really busy and take
- longer than we should. But don't let us slow you down: you're the
- one who's offering help here, and we should respect your time and
- contributions.
-
- When your patch is reviewed, one of these things will happen:
-
- * The reviewer will say "looks good to me" and your
- patch will get merged right into Tor. [Assuming we're not
- in the middle of a code-freeze window. If the codebase is
- frozen, your patch will go into the next release series.]
-
- * OR the reviewer will say "looks good, just needs some small
- changes!" And then the reviewer will make those changes,
- and merge the modified patch into Tor.
-
- * OR the reviewer will say "Here are some questions and
- comments," followed by a bunch of stuff that the reviewer
- thinks should change in your code, or questions that the
- reviewer has.
-
- At this point, you might want to make the requested changes
- yourself, and comment on the trac ticket once you have done
- so. Or if you disagree with any of the comments, you should
- say so! And if you won't have time to make some of the
- changes, you should say that too, so that other developers
- will be able to pick up the unfinished portion
-
- Congratulations! You have now written your first patch, and gotten
- it integrated into mainline Tor.
-
-
-Where do I go from here?
-------------------------
-
-doc/HACKING
-
-doc/WritingTests.txt
-
-torguts.git
-
-torspec.git
-
-The design paper
-
-freehaven.net/anonbib
-
-XXXX describe these and add links.
diff --git a/doc/HACKING b/doc/HACKING
deleted file mode 100644
index 5a1454e..0000000
--- a/doc/HACKING
+++ /dev/null
@@ -1,662 +0,0 @@
-Hacking Tor: An Incomplete Guide
-================================
-
-Important links
----------------
-
-For full information on how Tor is supposed to work, look at the files in
-https://gitweb.torproject.org/torspec.git/tree
-
-For an explanation of how to change Tor's design to work differently, look at
-https://gitweb.torproject.org/torspec.git/blob_plain/HEAD:/proposals/001-process.txt
-
-For the latest version of the code, get a copy of git, and
-
- git clone https://git.torproject.org/git/tor
-
-We talk about Tor on the tor-talk mailing list. Design proposals and
-discussion belong on the tor-dev mailing list. We hang around on
-irc.oftc.net, with general discussion happening on #tor and development
-happening on #tor-dev.
-
-For a nice quick-start guide to hacking on Tor, have a look at
-doc/GettingStarted.txt, included with the Tor distribution.
-
-How we use Git branches
------------------------
-
-Each main development series (like 0.2.1, 0.2.2, etc) has its main work
-applied to a single branch. At most one series can be the development series
-at a time; all other series are maintenance series that get bug-fixes only.
-The development series is built in a git branch called "master"; the
-maintenance series are built in branches called "maint-0.2.0", "maint-0.2.1",
-and so on. We regularly merge the active maint branches forward.
-
-For all series except the development series, we also have a "release" branch
-(as in "release-0.2.1"). The release series is based on the corresponding
-maintenance series, except that it deliberately lags the maint series for
-most of its patches, so that bugfix patches are not typically included in a
-maintenance release until they've been tested for a while in a development
-release. Occasionally, we'll merge an urgent bugfix into the release branch
-before it gets merged into maint, but that's rare.
-
-If you're working on a bugfix for a bug that occurs in a particular version,
-base your bugfix branch on the "maint" branch for the first supported series
-that has that bug. (As of June 2013, we're supporting 0.2.3 and later.) If
-you're working on a new feature, base it on the master branch.
-
-
-How we log changes
-------------------
-
-When you do a commit that needs a ChangeLog entry, add a new file to
-the "changes" toplevel subdirectory. It should have the format of a
-one-entry changelog section from the current ChangeLog file, as in
-
- o Major bugfixes:
- - Fix a potential buffer overflow. Fixes bug 99999; bugfix on
- 0.3.1.4-beta.
-
-To write a changes file, first categorize the change. Some common categories
-are: Minor bugfixes, Major bugfixes, Minor features, Major features, Code
-simplifications and refactoring. Then say what the change does. If
-it's a bugfix, mention what bug it fixes and when the bug was
-introduced. To find out which Git tag the change was introduced in,
-you can use "git describe --contains <sha1 of commit>".
-
-If at all possible, try to create this file in the same commit where you are
-making the change. Please give it a distinctive name that no other branch will
-use for the lifetime of your change. To verify the format of the changes file,
-you can use "make check-changes".
-
-When we go to make a release, we will concatenate all the entries
-in changes to make a draft changelog, and clear the directory. We'll
-then edit the draft changelog into a nice readable format.
-
-What needs a changes file?::
- A not-exhaustive list: Anything that might change user-visible
- behavior. Anything that changes internals, documentation, or the build
- system enough that somebody could notice. Big or interesting code
- rewrites. Anything about which somebody might plausibly wonder "when
- did that happen, and/or why did we do that" 6 months down the line.
-
-Why use changes files instead of Git commit messages?::
- Git commit messages are written for developers, not users, and they
- are nigh-impossible to revise after the fact.
-
-Why use changes files instead of entries in the ChangeLog?::
- Having every single commit touch the ChangeLog file tended to create
- zillions of merge conflicts.
-
-Useful tools
-------------
-
-These aren't strictly necessary for hacking on Tor, but they can help track
-down bugs.
-
-Jenkins
-~~~~~~~
-
-https://jenkins.torproject.org
-
-Dmalloc
-~~~~~~~
-
-The dmalloc library will keep track of memory allocation, so you can find out
-if we're leaking memory, doing any double-frees, or so on.
-
- dmalloc -l ~/dmalloc.log
- (run the commands it tells you)
- ./configure --with-dmalloc
-
-Valgrind
-~~~~~~~~
-
-valgrind --leak-check=yes --error-limit=no --show-reachable=yes src/or/tor
-
-(Note that if you get a zillion openssl warnings, you will also need to
-pass --undef-value-errors=no to valgrind, or rebuild your openssl
-with -DPURIFY.)
-
-Coverity
-~~~~~~~~
-
-Nick regularly runs the coverity static analyzer on the Tor codebase.
-
-The preprocessor define __COVERITY__ is used to work around instances
-where coverity picks up behavior that we wish to permit.
-
-clang Static Analyzer
-~~~~~~~~~~~~~~~~~~~~~
-
-The clang static analyzer can be run on the Tor codebase using Xcode (WIP)
-or a command-line build.
-
-The preprocessor define __clang_analyzer__ is used to work around instances
-where clang picks up behavior that we wish to permit.
-
-clang Runtime Sanitizers
-~~~~~~~~~~~~~~~~
-
-To build the Tor codebase with the clang Address and Undefined Behavior
-sanitizers, see the file contrib/clang/sanitize_blacklist.txt.
-
-Preprocessor workarounds for instances where clang picks up behavior that
-we wish to permit are also documented in the blacklist file.
-
-Running lcov for unit test coverage
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-Lcov is a utility that generates pretty HTML reports of test code coverage.
-To generate such a report:
-
------
- ./configure --enable-coverage
- make
- make coverage-html
- $BROWSER ./coverage_html/index.html
------
-
-This will run the tor unit test suite `./src/test/test` and generate the HTML
-coverage code report under the directory ./coverage_html/. To change the
-output directory, use `make coverage-html HTML_COVER_DIR=./funky_new_cov_dir`.
-
-Coverage diffs using lcov are not currently implemented, but are being
-investigated (as of July 2014).
-
-Running the unit tests
-~~~~~~~~~~~~~~~~~~~~~~
-
-To quickly run all the tests distributed with Tor:
------
- make check
------
-
-To run the fast unit tests only:
------
- make test
------
-
-To selectively run just some tests (the following can be combined
-arbitrarily):
------
- ./src/test/test <name_of_test> [<name of test 2>] ...
- ./src/test/test <prefix_of_name_of_test>.. [<prefix_of_name_of_test2>..] ...
- ./src/test/test :<name_of_excluded_test> [:<name_of_excluded_test2]...
------
-
-To run all tests, including those based on Stem or Chutney:
------
- make test-full
------
-
-To run all tests, including those basedd on Stem or Chutney that require a
-working connection to the internet:
------
- make test-full-online
------
-
-Running gcov for unit test coverage
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
------
- ./configure --enable-coverage
- make
- make check
- # or--- make test-full ? make test-full-online?
- mkdir coverage-output
- ./scripts/test/coverage coverage-output
------
-
-(On OSX, you'll need to start with "--enable-coverage CC=clang".)
-
-Then, look at the .gcov files in coverage-output. '-' before a line means
-that the compiler generated no code for that line. '######' means that the
-line was never reached. Lines with numbers were called that number of times.
-
-If that doesn't work:
- * Try configuring Tor with --disable-gcc-hardening
- * You might need to run 'make clean' after you run './configure'.
-
-If you make changes to Tor and want to get another set of coverage results,
-you can run "make reset-gcov" to clear the intermediary gcov output.
-
-If you have two different "coverage-output" directories, and you want to see
-a meaningful diff between them, you can run:
-
------
- ./scripts/test/cov-diff coverage-output1 coverage-output2 | less
------
-
-In this diff, any lines that were visited at least once will have coverage
-"1". This lets you inspect what you (probably) really want to know: which
-untested lines were changed? Are there any new untested lines?
-
-Running integration tests
-~~~~~~~~~~~~~~~~~~~~~~~~~
-
-We have the beginnings of a set of scripts to run integration tests using
-Chutney. To try them, set CHUTNEY_PATH to your chutney source directory, and
-run "make test-network".
-
-We also have scripts to run integration tests using Stem. To try them, set
-STEM_SOURCE_DIR to your Stem source directory, and run "test-stem".
-
-Profiling Tor with oprofile
-~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-The oprofile tool runs (on Linux only!) to tell you what functions Tor is
-spending its CPU time in, so we can identify berformance pottlenecks.
-
-Here are some basic instructions
-
- - Build tor with debugging symbols (you probably already have, unless
- you messed with CFLAGS during the build process).
- - Build all the libraries you care about with debugging symbols
- (probably you only care about libssl, maybe zlib and Libevent).
- - Copy this tor to a new directory
- - Copy all the libraries it uses to that dir too (ldd ./tor will
- tell you)
- - Set LD_LIBRARY_PATH to include that dir. ldd ./tor should now
- show you it's using the libs in that dir
- - Run that tor
- - Reset oprofiles counters/start it
- * "opcontrol --reset; opcontrol --start", if Nick remembers right.
- - After a while, have it dump the stats on tor and all the libs
- in that dir you created.
- * "opcontrol --dump;"
- * "opreport -l that_dir/*"
- - Profit
-
-Generating and analyzing a callgraph
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-1. Run ./scripts/maint/generate_callgraph.sh . This will generate a
- bunch of files in a new ./callgraph directory.
-
-2. Run ./scripts/maint/analyze_callgraph.py callgraph/src/*/* . This
- will do a lot of graph operations and then dump out a new
- "callgraph.pkl" file, containing data in Python's "pickle" format.
-
-3. Run ./scripts/maint/display_callgraph.py . It will display:
- - the number of functions reachable from each function.
- - all strongly-connnected components in the Tor callgraph
- - the largest bottlenecks in the largest SCC in the Tor callgraph.
-
-Note that currently the callgraph generator can't detect calls that pass
-through function pointers.
-
-Coding conventions
-------------------
-
-Patch checklist
-~~~~~~~~~~~~~~~
-
-If possible, send your patch as one of these (in descending order of
-preference)
-
- - A git branch we can pull from
- - Patches generated by git format-patch
- - A unified diff
-
-Did you remember...
-
- - To build your code while configured with --enable-gcc-warnings?
- - To run "make check-spaces" on your code?
- - To run "make check-docs" to see whether all new options are on
- the manpage?
- - To write unit tests, as possible?
- - To base your code on the appropriate branch?
- - To include a file in the "changes" directory as appropriate?
-
-Whitespace and C conformance
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-Invoke "make check-spaces" from time to time, so it can tell you about
-deviations from our C whitespace style. Generally, we use:
-
- - Unix-style line endings
- - K&R-style indentation
- - No space before newlines
- - A blank line at the end of each file
- - Never more than one blank line in a row
- - Always spaces, never tabs
- - No more than 79-columns per line.
- - Two spaces per indent.
- - A space between control keywords and their corresponding paren
- "if (x)", "while (x)", and "switch (x)", never "if(x)", "while(x)", or
- "switch(x)".
- - A space between anything and an open brace.
- - No space between a function name and an opening paren. "puts(x)", not
- "puts (x)".
- - Function declarations at the start of the line.
-
-We try hard to build without warnings everywhere. In particular, if you're
-using gcc, you should invoke the configure script with the option
-"--enable-gcc-warnings". This will give a bunch of extra warning flags to
-the compiler, and help us find divergences from our preferred C style.
-
-Getting emacs to edit Tor source properly
-^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-
-Nick likes to put the following snippet in his .emacs file:
-
------
- (add-hook 'c-mode-hook
- (lambda ()
- (font-lock-mode 1)
- (set-variable 'show-trailing-whitespace t)
-
- (let ((fname (expand-file-name (buffer-file-name))))
- (cond
- ((string-match "^/home/nickm/src/libevent" fname)
- (set-variable 'indent-tabs-mode t)
- (set-variable 'c-basic-offset 4)
- (set-variable 'tab-width 4))
- ((string-match "^/home/nickm/src/tor" fname)
- (set-variable 'indent-tabs-mode nil)
- (set-variable 'c-basic-offset 2))
- ((string-match "^/home/nickm/src/openssl" fname)
- (set-variable 'indent-tabs-mode t)
- (set-variable 'c-basic-offset 8)
- (set-variable 'tab-width 8))
- ))))
------
-
-You'll note that it defaults to showing all trailing whitespace. The "cond"
-test detects whether the file is one of a few C free software projects that I
-often edit, and sets up the indentation level and tab preferences to match
-what they want.
-
-If you want to try this out, you'll need to change the filename regex
-patterns to match where you keep your Tor files.
-
-If you use emacs for editing Tor and nothing else, you could always just say:
-
------
- (add-hook 'c-mode-hook
- (lambda ()
- (font-lock-mode 1)
- (set-variable 'show-trailing-whitespace t)
- (set-variable 'indent-tabs-mode nil)
- (set-variable 'c-basic-offset 2)))
------
-
-There is probably a better way to do this. No, we are probably not going
-to clutter the files with emacs stuff.
-
-
-Functions to use
-~~~~~~~~~~~~~~~~
-
-We have some wrapper functions like tor_malloc, tor_free, tor_strdup, and
-tor_gettimeofday; use them instead of their generic equivalents. (They
-always succeed or exit.)
-
-You can get a full list of the compatibility functions that Tor provides by
-looking through src/common/util.h and src/common/compat.h. You can see the
-available containers in src/common/containers.h. You should probably
-familiarize yourself with these modules before you write too much code, or
-else you'll wind up reinventing the wheel.
-
-Use 'INLINE' instead of 'inline', so that we work properly on Windows.
-
-Calling and naming conventions
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-Whenever possible, functions should return -1 on error and 0 on success.
-
-For multi-word identifiers, use lowercase words combined with
-underscores. (e.g., "multi_word_identifier"). Use ALL_CAPS for macros and
-constants.
-
-Typenames should end with "_t".
-
-Function names should be prefixed with a module name or object name. (In
-general, code to manipulate an object should be a module with the same name
-as the object, so it's hard to tell which convention is used.)
-
-Functions that do things should have imperative-verb names
-(e.g. buffer_clear, buffer_resize); functions that return booleans should
-have predicate names (e.g. buffer_is_empty, buffer_needs_resizing).
-
-If you find that you have four or more possible return code values, it's
-probably time to create an enum. If you find that you are passing three or
-more flags to a function, it's probably time to create a flags argument that
-takes a bitfield.
-
-What To Optimize
-~~~~~~~~~~~~~~~~
-
-Don't optimize anything if it's not in the critical path. Right now, the
-critical path seems to be AES, logging, and the network itself. Feel free to
-do your own profiling to determine otherwise.
-
-Log conventions
-~~~~~~~~~~~~~~~
-
-https://www.torproject.org/docs/faq#LogLevel
-
-No error or warning messages should be expected during normal OR or OP
-operation.
-
-If a library function is currently called such that failure always means ERR,
-then the library function should log WARN and let the caller log ERR.
-
-Every message of severity INFO or higher should either (A) be intelligible
-to end-users who don't know the Tor source; or (B) somehow inform the
-end-users that they aren't expected to understand the message (perhaps
-with a string like "internal error"). Option (A) is to be preferred to
-option (B).
-
-Doxygen
-~~~~~~~~
-
-We use the 'doxygen' utility to generate documentation from our
-source code. Here's how to use it:
-
- 1. Begin every file that should be documented with
- /**
- * \file filename.c
- * \brief Short description of the file.
- **/
-
- (Doxygen will recognize any comment beginning with /** as special.)
-
- 2. Before any function, structure, #define, or variable you want to
- document, add a comment of the form:
-
- /** Describe the function's actions in imperative sentences.
- *
- * Use blank lines for paragraph breaks
- * - and
- * - hyphens
- * - for
- * - lists.
- *
- * Write <b>argument_names</b> in boldface.
- *
- * \code
- * place_example_code();
- * between_code_and_endcode_commands();
- * \endcode
- */
-
- 3. Make sure to escape the characters "<", ">", "\", "%" and "#" as "\<",
- "\>", "\\", "\%", and "\#".
-
- 4. To document structure members, you can use two forms:
-
- struct foo {
- /** You can put the comment before an element; */
- int a;
- int b; /**< Or use the less-than symbol to put the comment
- * after the element. */
- };
-
- 5. To generate documentation from the Tor source code, type:
-
- $ doxygen -g
-
- To generate a file called 'Doxyfile'. Edit that file and run
- 'doxygen' to generate the API documentation.
-
- 6. See the Doxygen manual for more information; this summary just
- scratches the surface.
-
-Doxygen comment conventions
-^^^^^^^^^^^^^^^^^^^^^^^^^^^
-
-Say what functions do as a series of one or more imperative sentences, as
-though you were telling somebody how to be the function. In other words, DO
-NOT say:
-
- /** The strtol function parses a number.
- *
- * nptr -- the string to parse. It can include whitespace.
- * endptr -- a string pointer to hold the first thing that is not part
- * of the number, if present.
- * base -- the numeric base.
- * returns: the resulting number.
- */
- long strtol(const char *nptr, char **nptr, int base);
-
-Instead, please DO say:
-
- /** Parse a number in radix <b>base</b> from the string <b>nptr</b>,
- * and return the result. Skip all leading whitespace. If
- * <b>endptr</b> is not NULL, set *<b>endptr</b> to the first character
- * after the number parsed.
- **/
- long strtol(const char *nptr, char **nptr, int base);
-
-Doxygen comments are the contract in our abstraction-by-contract world: if
-the functions that call your function rely on it doing something, then your
-function should mention that it does that something in the documentation. If
-you rely on a function doing something beyond what is in its documentation,
-then you should watch out, or it might do something else later.
-
-Putting out a new release
--------------------------
-
-Here are the steps Roger takes when putting out a new Tor release:
-
-1) Use it for a while, as a client, as a relay, as a hidden service,
-and as a directory authority. See if it has any obvious bugs, and
-resolve those.
-
-1.5) As applicable, merge the maint-X branch into the release-X branch.
-
-2) Gather the changes/* files into a changelog entry, rewriting many
-of them and reordering to focus on what users and funders would find
-interesting and understandable.
-
- 2.1) Make sure that everything that wants a bug number has one.
- Make sure that everything which is a bugfix says what version
- it was a bugfix on.
- 2.2) Concatenate them.
- 2.3) Sort them by section. Within each section, sort by "version it's
- a bugfix on", else by numerical ticket order.
-
- 2.4) Clean them up:
-
- Standard idioms:
- "Fixes bug 9999; bugfix on 0.3.3.3-alpha."
-
- One space after a period.
-
- Make stuff very terse
-
- Make sure each section name ends with a colon
-
- Describe the user-visible problem right away
-
- Mention relevant config options by name. If they're rare or unusual,
- remind people what they're for
-
- Avoid starting lines with open-paren
-
- Present and imperative tense: not past.
-
- 'Relays', not 'servers' or 'nodes' or 'Tor relays'.
-
- "Stop FOOing", not "Fix a bug where we would FOO".
-
- Try not to let any given section be longer than about a page. Break up
- long sections into subsections by some sort of common subtopic. This
- guideline is especially important when organizing Release Notes for
- new stable releases.
-
- If a given changes stanza showed up in a different release (e.g.
- maint-0.2.1), be sure to make the stanzas identical (so people can
- distinguish if these are the same change).
-
- 2.5) Merge them in.
-
- 2.6) Clean everything one last time.
-
- 2.7) Run ./scripts/maint/format_changelog.py to make it prettier.
-
-3) Compose a short release blurb to highlight the user-facing
-changes. Insert said release blurb into the ChangeLog stanza. If it's
-a stable release, add it to the ReleaseNotes file too. If we're adding
-to a release-0.2.x branch, manually commit the changelogs to the later
-git branches too.
-
-4) In maint-0.2.x, bump the version number in configure.ac and run
- scripts/maint/updateVersions.pl to update version numbers in other
- places, and commit. Then merge maint-0.2.x into release-0.2.x.
-
- (NOTE: TO bump the version number, edit configure.ac, and then run
- either make, or 'perl scripts/maint/updateVersions.pl', depending on
- your version.)
-
-5) Make dist, put the tarball up somewhere, and tell #tor about it. Wait
-a while to see if anybody has problems building it. Try to get Sebastian
-or somebody to try building it on Windows.
-
-6) Get at least two of weasel/arma/sebastian to put the new version number
-in their approved versions list.
-
-7) Sign the tarball, then sign and push the git tag:
- gpg -ba <the_tarball>
- git tag -u <keyid> tor-0.2.x.y-status
- git push origin tag tor-0.2.x.y-status
-
-8a) scp the tarball and its sig to the dist website, i.e.
-/srv/dist-master.torproject.org/htdocs/ on dist-master. When you want
-it to go live, you run "static-update-component dist.torproject.org"
-on dist-master.
-
-8b) Edit "include/versions.wmi" and "Makefile" to note the new version.
-
-9) Email the packagers (cc'ing tor-assistants) that a new tarball is up.
- The current list of packagers is:
- {weasel,gk,mikeperry} at torproject dot org
- {blueness} at gentoo dot org
- {paul} at invizbox dot io
- {ondrej.mikle} at gmail dot com
- {lfleischer} at archlinux dot org
-
-10) Add the version number to Trac. To do this, go to Trac, log in,
-select "Admin" near the top of the screen, then select "Versions" from
-the menu on the left. At the right, there will be an "Add version"
-box. By convention, we enter the version in the form "Tor:
-0.2.2.23-alpha" (or whatever the version is), and we select the date as
-the date in the ChangeLog.
-
-11) Forward-port the ChangeLog.
-
-12) Wait up to a day or two (for a development release), or until most
-packages are up (for a stable release), and mail the release blurb and
-changelog to tor-talk or tor-announce.
-
- (We might be moving to faster announcements, but don't announce until
- the website is at least updated.)
-
-13) If it's a stable release, bump the version number in the maint-x.y.z
- branch to "newversion-dev", and do a "merge -s ours" merge to avoid
- taking that change into master. Do a similar 'merge -s theirs'
- merge to get the change (and only that change) into release. (Some
- of the build scripts require that maint merge cleanly into release.)
-
diff --git a/doc/HACKING/GettingStarted.txt b/doc/HACKING/GettingStarted.txt
new file mode 100644
index 0000000..1f4b434
--- /dev/null
+++ b/doc/HACKING/GettingStarted.txt
@@ -0,0 +1,207 @@
+
+
+(DRAFT)
+
+
+
+Getting started in Tor development
+==================================
+
+Congratulations! You've found this file, and you're reading it! This
+means that you might be interested in getting started in developing Tor.
+
+(This guide is just about Tor itself--the small network program at the
+heart of the Tor network--and not about all the other programs in the
+whole Tor ecosystem.)
+
+
+If you are looking for a more bare-bones, less user-friendly information
+dump of important information, you might like reading doc/HACKING
+instead. You should probably read it before you write your first patch.
+
+
+Required background
+-------------------
+
+First, I'm going to assume that you can build Tor from source, and that
+you know enough of the C language to read and write it. (See the README
+file that comes with the Tor source for more information on building it,
+and any high-quality guide to C for information on programming.)
+
+I'm also going to assume that you know a little bit about how to use
+Git, or that you're able to fillow one of the several excellent guides
+at http://git-scm.org to learn.
+
+Most Tor developers develop using some Unix-based system, such as Linux,
+BSD, or OSX. It's okay to develop on Windows if you want, but you're
+going to have a more difficult time.
+
+
+Getting your first patch into Tor
+---------------------------------
+
+Once you've reached this point, here's what you need to know.
+
+ 1) Get the source.
+
+ We keep our source under version control in Git. To get the latest
+ version, run
+ git clone https://git.torproject.org/git/tor
+
+ This will give you a checkout of the master branch. If you're
+ going to fix a bug that appears in a stable version, check out the
+ appropriate "maint" branch, as in:
+
+ git checkout maint-0.2.7
+
+ 2) Find your way around the source
+
+ Our overall code structure is explained in the "torguts" documents,
+ currently at
+ git clone https://git.torproject.org/user/nickm/torguts.git
+
+ Find a part of the code that looks interesting to you, and start
+ looking around it to see how it fits together!
+
+ We do some unusual things in our codebase. Our testing-related
+ practices and kludges are explained in doc/WritingTests.txt.
+
+ If you see something that doesn't make sense, we love to get
+ questions!
+
+ 3) Find something cool to hack on.
+
+ You may already have a good idea of what you'd like to work on, or
+ you might be looking for a way to contribute.
+
+ Many people have gotten started by looking for an area where they
+ personally felt Tor was underperforming, and investigating ways to
+ fix it. If you're looking for ideas, you can head to our bug
+ tracker at trac.torproject.org and look for tickets that have
+ received the "easy" tag: these are ones that developers think would
+ be pretty simple for a new person to work on. For a bigger
+ challenge, you might want to look for tickets with the "lorax"
+ keyword: these are tickets that the developers think might be a
+ good idea to build, but which we have no time to work on any time
+ soon.
+
+ Or you might find another open ticket that piques your
+ interest. It's all fine!
+
+ For your first patch, it is probably NOT a good idea to make
+ something huge or invasive. In particular, you should probably
+ avoid:
+ * Major changes spread across many parts of the codebase.
+ * Major changes to programming practice or coding style.
+ * Huge new features or protocol changes.
+
+ 4) Meet the developers!
+
+ We discuss stuff on the tor-dev mailing list and on the #tor-dev
+ IRC channel on OFTC. We're generally friendly and approachable,
+ and we like to talk about how Tor fits together. If we have ideas
+ about how something should be implemented, we'll be happy to share
+ them.
+
+ We currently have a patch workshop at least once a week, where
+ people share patches they've made and discuss how to make them
+ better. The time might change in the future, but generally,
+ there's no bad time to talk, and ask us about patch ideas.
+
+ 5) Do you need to write a design proposal?
+
+ If your idea is very large, or it will require a change to Tor's
+ protocols, there needs to be a written design proposal before it
+ can be merged. (We use this process to manage changes in the
+ protocols.) To write one, see the instructions at
+ https://gitweb.torproject.org/torspec.git/tree/proposals/001-process.txt
+ . If you'd like help writing a proposal, just ask! We're happy to
+ help out with good ideas.
+
+ You might also like to look around the rest of that directory, to
+ see more about open and past proposed changes to Tor's behavior.
+
+ 6) Writing your patch
+
+ As you write your code, you'll probably want it to fit in with the
+ standards of the rest of the Tor codebase so it will be easy for us
+ to review and merge. You can learn our coding standards in
+ doc/HACKING.
+
+ If your patch is large and/or is divided into multiple logical
+ components, remember to divide it into a series of Git commits. A
+ series of small changes is much easier to review than one big lump.
+
+ 7) Testing your patch
+
+ We prefer that all new or modified code have unit tests for it to
+ ensure that it runs correctly. Also, all code should actually be
+ _run_ by somebody, to make sure it works.
+
+ See doc/WritingTests.txt for more information on how we test things
+ in Tor. If you'd like any help writing tests, just ask! We're
+ glad to help out.
+
+ 8) Submitting your patch
+
+ We review patches through tickets on our bugtracker at
+ trac.torproject.org. You can either upload your patches there, or
+ put them at a public git repository somewhere we can fetch them
+ (like github or bitbucket) and then paste a link on the appropriate
+ trac ticket.
+
+ Once your patches are available, write a short explanation of what
+ you've done on trac, and then change the status of the ticket to
+ needs_review.
+
+ 9) Review, Revision, and Merge
+
+ With any luck, somebody will review your patch soon! If not, you
+ can ask on the IRC channel; sometimes we get really busy and take
+ longer than we should. But don't let us slow you down: you're the
+ one who's offering help here, and we should respect your time and
+ contributions.
+
+ When your patch is reviewed, one of these things will happen:
+
+ * The reviewer will say "looks good to me" and your
+ patch will get merged right into Tor. [Assuming we're not
+ in the middle of a code-freeze window. If the codebase is
+ frozen, your patch will go into the next release series.]
+
+ * OR the reviewer will say "looks good, just needs some small
+ changes!" And then the reviewer will make those changes,
+ and merge the modified patch into Tor.
+
+ * OR the reviewer will say "Here are some questions and
+ comments," followed by a bunch of stuff that the reviewer
+ thinks should change in your code, or questions that the
+ reviewer has.
+
+ At this point, you might want to make the requested changes
+ yourself, and comment on the trac ticket once you have done
+ so. Or if you disagree with any of the comments, you should
+ say so! And if you won't have time to make some of the
+ changes, you should say that too, so that other developers
+ will be able to pick up the unfinished portion
+
+ Congratulations! You have now written your first patch, and gotten
+ it integrated into mainline Tor.
+
+
+Where do I go from here?
+------------------------
+
+doc/HACKING
+
+doc/WritingTests.txt
+
+torguts.git
+
+torspec.git
+
+The design paper
+
+freehaven.net/anonbib
+
+XXXX describe these and add links.
diff --git a/doc/HACKING/HACKING_old b/doc/HACKING/HACKING_old
new file mode 100644
index 0000000..5a1454e
--- /dev/null
+++ b/doc/HACKING/HACKING_old
@@ -0,0 +1,662 @@
+Hacking Tor: An Incomplete Guide
+================================
+
+Important links
+---------------
+
+For full information on how Tor is supposed to work, look at the files in
+https://gitweb.torproject.org/torspec.git/tree
+
+For an explanation of how to change Tor's design to work differently, look at
+https://gitweb.torproject.org/torspec.git/blob_plain/HEAD:/proposals/001-process.txt
+
+For the latest version of the code, get a copy of git, and
+
+ git clone https://git.torproject.org/git/tor
+
+We talk about Tor on the tor-talk mailing list. Design proposals and
+discussion belong on the tor-dev mailing list. We hang around on
+irc.oftc.net, with general discussion happening on #tor and development
+happening on #tor-dev.
+
+For a nice quick-start guide to hacking on Tor, have a look at
+doc/GettingStarted.txt, included with the Tor distribution.
+
+How we use Git branches
+-----------------------
+
+Each main development series (like 0.2.1, 0.2.2, etc) has its main work
+applied to a single branch. At most one series can be the development series
+at a time; all other series are maintenance series that get bug-fixes only.
+The development series is built in a git branch called "master"; the
+maintenance series are built in branches called "maint-0.2.0", "maint-0.2.1",
+and so on. We regularly merge the active maint branches forward.
+
+For all series except the development series, we also have a "release" branch
+(as in "release-0.2.1"). The release series is based on the corresponding
+maintenance series, except that it deliberately lags the maint series for
+most of its patches, so that bugfix patches are not typically included in a
+maintenance release until they've been tested for a while in a development
+release. Occasionally, we'll merge an urgent bugfix into the release branch
+before it gets merged into maint, but that's rare.
+
+If you're working on a bugfix for a bug that occurs in a particular version,
+base your bugfix branch on the "maint" branch for the first supported series
+that has that bug. (As of June 2013, we're supporting 0.2.3 and later.) If
+you're working on a new feature, base it on the master branch.
+
+
+How we log changes
+------------------
+
+When you do a commit that needs a ChangeLog entry, add a new file to
+the "changes" toplevel subdirectory. It should have the format of a
+one-entry changelog section from the current ChangeLog file, as in
+
+ o Major bugfixes:
+ - Fix a potential buffer overflow. Fixes bug 99999; bugfix on
+ 0.3.1.4-beta.
+
+To write a changes file, first categorize the change. Some common categories
+are: Minor bugfixes, Major bugfixes, Minor features, Major features, Code
+simplifications and refactoring. Then say what the change does. If
+it's a bugfix, mention what bug it fixes and when the bug was
+introduced. To find out which Git tag the change was introduced in,
+you can use "git describe --contains <sha1 of commit>".
+
+If at all possible, try to create this file in the same commit where you are
+making the change. Please give it a distinctive name that no other branch will
+use for the lifetime of your change. To verify the format of the changes file,
+you can use "make check-changes".
+
+When we go to make a release, we will concatenate all the entries
+in changes to make a draft changelog, and clear the directory. We'll
+then edit the draft changelog into a nice readable format.
+
+What needs a changes file?::
+ A not-exhaustive list: Anything that might change user-visible
+ behavior. Anything that changes internals, documentation, or the build
+ system enough that somebody could notice. Big or interesting code
+ rewrites. Anything about which somebody might plausibly wonder "when
+ did that happen, and/or why did we do that" 6 months down the line.
+
+Why use changes files instead of Git commit messages?::
+ Git commit messages are written for developers, not users, and they
+ are nigh-impossible to revise after the fact.
+
+Why use changes files instead of entries in the ChangeLog?::
+ Having every single commit touch the ChangeLog file tended to create
+ zillions of merge conflicts.
+
+Useful tools
+------------
+
+These aren't strictly necessary for hacking on Tor, but they can help track
+down bugs.
+
+Jenkins
+~~~~~~~
+
+https://jenkins.torproject.org
+
+Dmalloc
+~~~~~~~
+
+The dmalloc library will keep track of memory allocation, so you can find out
+if we're leaking memory, doing any double-frees, or so on.
+
+ dmalloc -l ~/dmalloc.log
+ (run the commands it tells you)
+ ./configure --with-dmalloc
+
+Valgrind
+~~~~~~~~
+
+valgrind --leak-check=yes --error-limit=no --show-reachable=yes src/or/tor
+
+(Note that if you get a zillion openssl warnings, you will also need to
+pass --undef-value-errors=no to valgrind, or rebuild your openssl
+with -DPURIFY.)
+
+Coverity
+~~~~~~~~
+
+Nick regularly runs the coverity static analyzer on the Tor codebase.
+
+The preprocessor define __COVERITY__ is used to work around instances
+where coverity picks up behavior that we wish to permit.
+
+clang Static Analyzer
+~~~~~~~~~~~~~~~~~~~~~
+
+The clang static analyzer can be run on the Tor codebase using Xcode (WIP)
+or a command-line build.
+
+The preprocessor define __clang_analyzer__ is used to work around instances
+where clang picks up behavior that we wish to permit.
+
+clang Runtime Sanitizers
+~~~~~~~~~~~~~~~~
+
+To build the Tor codebase with the clang Address and Undefined Behavior
+sanitizers, see the file contrib/clang/sanitize_blacklist.txt.
+
+Preprocessor workarounds for instances where clang picks up behavior that
+we wish to permit are also documented in the blacklist file.
+
+Running lcov for unit test coverage
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Lcov is a utility that generates pretty HTML reports of test code coverage.
+To generate such a report:
+
+-----
+ ./configure --enable-coverage
+ make
+ make coverage-html
+ $BROWSER ./coverage_html/index.html
+-----
+
+This will run the tor unit test suite `./src/test/test` and generate the HTML
+coverage code report under the directory ./coverage_html/. To change the
+output directory, use `make coverage-html HTML_COVER_DIR=./funky_new_cov_dir`.
+
+Coverage diffs using lcov are not currently implemented, but are being
+investigated (as of July 2014).
+
+Running the unit tests
+~~~~~~~~~~~~~~~~~~~~~~
+
+To quickly run all the tests distributed with Tor:
+-----
+ make check
+-----
+
+To run the fast unit tests only:
+-----
+ make test
+-----
+
+To selectively run just some tests (the following can be combined
+arbitrarily):
+-----
+ ./src/test/test <name_of_test> [<name of test 2>] ...
+ ./src/test/test <prefix_of_name_of_test>.. [<prefix_of_name_of_test2>..] ...
+ ./src/test/test :<name_of_excluded_test> [:<name_of_excluded_test2]...
+-----
+
+To run all tests, including those based on Stem or Chutney:
+-----
+ make test-full
+-----
+
+To run all tests, including those basedd on Stem or Chutney that require a
+working connection to the internet:
+-----
+ make test-full-online
+-----
+
+Running gcov for unit test coverage
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+-----
+ ./configure --enable-coverage
+ make
+ make check
+ # or--- make test-full ? make test-full-online?
+ mkdir coverage-output
+ ./scripts/test/coverage coverage-output
+-----
+
+(On OSX, you'll need to start with "--enable-coverage CC=clang".)
+
+Then, look at the .gcov files in coverage-output. '-' before a line means
+that the compiler generated no code for that line. '######' means that the
+line was never reached. Lines with numbers were called that number of times.
+
+If that doesn't work:
+ * Try configuring Tor with --disable-gcc-hardening
+ * You might need to run 'make clean' after you run './configure'.
+
+If you make changes to Tor and want to get another set of coverage results,
+you can run "make reset-gcov" to clear the intermediary gcov output.
+
+If you have two different "coverage-output" directories, and you want to see
+a meaningful diff between them, you can run:
+
+-----
+ ./scripts/test/cov-diff coverage-output1 coverage-output2 | less
+-----
+
+In this diff, any lines that were visited at least once will have coverage
+"1". This lets you inspect what you (probably) really want to know: which
+untested lines were changed? Are there any new untested lines?
+
+Running integration tests
+~~~~~~~~~~~~~~~~~~~~~~~~~
+
+We have the beginnings of a set of scripts to run integration tests using
+Chutney. To try them, set CHUTNEY_PATH to your chutney source directory, and
+run "make test-network".
+
+We also have scripts to run integration tests using Stem. To try them, set
+STEM_SOURCE_DIR to your Stem source directory, and run "test-stem".
+
+Profiling Tor with oprofile
+~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+The oprofile tool runs (on Linux only!) to tell you what functions Tor is
+spending its CPU time in, so we can identify berformance pottlenecks.
+
+Here are some basic instructions
+
+ - Build tor with debugging symbols (you probably already have, unless
+ you messed with CFLAGS during the build process).
+ - Build all the libraries you care about with debugging symbols
+ (probably you only care about libssl, maybe zlib and Libevent).
+ - Copy this tor to a new directory
+ - Copy all the libraries it uses to that dir too (ldd ./tor will
+ tell you)
+ - Set LD_LIBRARY_PATH to include that dir. ldd ./tor should now
+ show you it's using the libs in that dir
+ - Run that tor
+ - Reset oprofiles counters/start it
+ * "opcontrol --reset; opcontrol --start", if Nick remembers right.
+ - After a while, have it dump the stats on tor and all the libs
+ in that dir you created.
+ * "opcontrol --dump;"
+ * "opreport -l that_dir/*"
+ - Profit
+
+Generating and analyzing a callgraph
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+1. Run ./scripts/maint/generate_callgraph.sh . This will generate a
+ bunch of files in a new ./callgraph directory.
+
+2. Run ./scripts/maint/analyze_callgraph.py callgraph/src/*/* . This
+ will do a lot of graph operations and then dump out a new
+ "callgraph.pkl" file, containing data in Python's "pickle" format.
+
+3. Run ./scripts/maint/display_callgraph.py . It will display:
+ - the number of functions reachable from each function.
+ - all strongly-connnected components in the Tor callgraph
+ - the largest bottlenecks in the largest SCC in the Tor callgraph.
+
+Note that currently the callgraph generator can't detect calls that pass
+through function pointers.
+
+Coding conventions
+------------------
+
+Patch checklist
+~~~~~~~~~~~~~~~
+
+If possible, send your patch as one of these (in descending order of
+preference)
+
+ - A git branch we can pull from
+ - Patches generated by git format-patch
+ - A unified diff
+
+Did you remember...
+
+ - To build your code while configured with --enable-gcc-warnings?
+ - To run "make check-spaces" on your code?
+ - To run "make check-docs" to see whether all new options are on
+ the manpage?
+ - To write unit tests, as possible?
+ - To base your code on the appropriate branch?
+ - To include a file in the "changes" directory as appropriate?
+
+Whitespace and C conformance
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Invoke "make check-spaces" from time to time, so it can tell you about
+deviations from our C whitespace style. Generally, we use:
+
+ - Unix-style line endings
+ - K&R-style indentation
+ - No space before newlines
+ - A blank line at the end of each file
+ - Never more than one blank line in a row
+ - Always spaces, never tabs
+ - No more than 79-columns per line.
+ - Two spaces per indent.
+ - A space between control keywords and their corresponding paren
+ "if (x)", "while (x)", and "switch (x)", never "if(x)", "while(x)", or
+ "switch(x)".
+ - A space between anything and an open brace.
+ - No space between a function name and an opening paren. "puts(x)", not
+ "puts (x)".
+ - Function declarations at the start of the line.
+
+We try hard to build without warnings everywhere. In particular, if you're
+using gcc, you should invoke the configure script with the option
+"--enable-gcc-warnings". This will give a bunch of extra warning flags to
+the compiler, and help us find divergences from our preferred C style.
+
+Getting emacs to edit Tor source properly
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Nick likes to put the following snippet in his .emacs file:
+
+-----
+ (add-hook 'c-mode-hook
+ (lambda ()
+ (font-lock-mode 1)
+ (set-variable 'show-trailing-whitespace t)
+
+ (let ((fname (expand-file-name (buffer-file-name))))
+ (cond
+ ((string-match "^/home/nickm/src/libevent" fname)
+ (set-variable 'indent-tabs-mode t)
+ (set-variable 'c-basic-offset 4)
+ (set-variable 'tab-width 4))
+ ((string-match "^/home/nickm/src/tor" fname)
+ (set-variable 'indent-tabs-mode nil)
+ (set-variable 'c-basic-offset 2))
+ ((string-match "^/home/nickm/src/openssl" fname)
+ (set-variable 'indent-tabs-mode t)
+ (set-variable 'c-basic-offset 8)
+ (set-variable 'tab-width 8))
+ ))))
+-----
+
+You'll note that it defaults to showing all trailing whitespace. The "cond"
+test detects whether the file is one of a few C free software projects that I
+often edit, and sets up the indentation level and tab preferences to match
+what they want.
+
+If you want to try this out, you'll need to change the filename regex
+patterns to match where you keep your Tor files.
+
+If you use emacs for editing Tor and nothing else, you could always just say:
+
+-----
+ (add-hook 'c-mode-hook
+ (lambda ()
+ (font-lock-mode 1)
+ (set-variable 'show-trailing-whitespace t)
+ (set-variable 'indent-tabs-mode nil)
+ (set-variable 'c-basic-offset 2)))
+-----
+
+There is probably a better way to do this. No, we are probably not going
+to clutter the files with emacs stuff.
+
+
+Functions to use
+~~~~~~~~~~~~~~~~
+
+We have some wrapper functions like tor_malloc, tor_free, tor_strdup, and
+tor_gettimeofday; use them instead of their generic equivalents. (They
+always succeed or exit.)
+
+You can get a full list of the compatibility functions that Tor provides by
+looking through src/common/util.h and src/common/compat.h. You can see the
+available containers in src/common/containers.h. You should probably
+familiarize yourself with these modules before you write too much code, or
+else you'll wind up reinventing the wheel.
+
+Use 'INLINE' instead of 'inline', so that we work properly on Windows.
+
+Calling and naming conventions
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Whenever possible, functions should return -1 on error and 0 on success.
+
+For multi-word identifiers, use lowercase words combined with
+underscores. (e.g., "multi_word_identifier"). Use ALL_CAPS for macros and
+constants.
+
+Typenames should end with "_t".
+
+Function names should be prefixed with a module name or object name. (In
+general, code to manipulate an object should be a module with the same name
+as the object, so it's hard to tell which convention is used.)
+
+Functions that do things should have imperative-verb names
+(e.g. buffer_clear, buffer_resize); functions that return booleans should
+have predicate names (e.g. buffer_is_empty, buffer_needs_resizing).
+
+If you find that you have four or more possible return code values, it's
+probably time to create an enum. If you find that you are passing three or
+more flags to a function, it's probably time to create a flags argument that
+takes a bitfield.
+
+What To Optimize
+~~~~~~~~~~~~~~~~
+
+Don't optimize anything if it's not in the critical path. Right now, the
+critical path seems to be AES, logging, and the network itself. Feel free to
+do your own profiling to determine otherwise.
+
+Log conventions
+~~~~~~~~~~~~~~~
+
+https://www.torproject.org/docs/faq#LogLevel
+
+No error or warning messages should be expected during normal OR or OP
+operation.
+
+If a library function is currently called such that failure always means ERR,
+then the library function should log WARN and let the caller log ERR.
+
+Every message of severity INFO or higher should either (A) be intelligible
+to end-users who don't know the Tor source; or (B) somehow inform the
+end-users that they aren't expected to understand the message (perhaps
+with a string like "internal error"). Option (A) is to be preferred to
+option (B).
+
+Doxygen
+~~~~~~~~
+
+We use the 'doxygen' utility to generate documentation from our
+source code. Here's how to use it:
+
+ 1. Begin every file that should be documented with
+ /**
+ * \file filename.c
+ * \brief Short description of the file.
+ **/
+
+ (Doxygen will recognize any comment beginning with /** as special.)
+
+ 2. Before any function, structure, #define, or variable you want to
+ document, add a comment of the form:
+
+ /** Describe the function's actions in imperative sentences.
+ *
+ * Use blank lines for paragraph breaks
+ * - and
+ * - hyphens
+ * - for
+ * - lists.
+ *
+ * Write <b>argument_names</b> in boldface.
+ *
+ * \code
+ * place_example_code();
+ * between_code_and_endcode_commands();
+ * \endcode
+ */
+
+ 3. Make sure to escape the characters "<", ">", "\", "%" and "#" as "\<",
+ "\>", "\\", "\%", and "\#".
+
+ 4. To document structure members, you can use two forms:
+
+ struct foo {
+ /** You can put the comment before an element; */
+ int a;
+ int b; /**< Or use the less-than symbol to put the comment
+ * after the element. */
+ };
+
+ 5. To generate documentation from the Tor source code, type:
+
+ $ doxygen -g
+
+ To generate a file called 'Doxyfile'. Edit that file and run
+ 'doxygen' to generate the API documentation.
+
+ 6. See the Doxygen manual for more information; this summary just
+ scratches the surface.
+
+Doxygen comment conventions
+^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Say what functions do as a series of one or more imperative sentences, as
+though you were telling somebody how to be the function. In other words, DO
+NOT say:
+
+ /** The strtol function parses a number.
+ *
+ * nptr -- the string to parse. It can include whitespace.
+ * endptr -- a string pointer to hold the first thing that is not part
+ * of the number, if present.
+ * base -- the numeric base.
+ * returns: the resulting number.
+ */
+ long strtol(const char *nptr, char **nptr, int base);
+
+Instead, please DO say:
+
+ /** Parse a number in radix <b>base</b> from the string <b>nptr</b>,
+ * and return the result. Skip all leading whitespace. If
+ * <b>endptr</b> is not NULL, set *<b>endptr</b> to the first character
+ * after the number parsed.
+ **/
+ long strtol(const char *nptr, char **nptr, int base);
+
+Doxygen comments are the contract in our abstraction-by-contract world: if
+the functions that call your function rely on it doing something, then your
+function should mention that it does that something in the documentation. If
+you rely on a function doing something beyond what is in its documentation,
+then you should watch out, or it might do something else later.
+
+Putting out a new release
+-------------------------
+
+Here are the steps Roger takes when putting out a new Tor release:
+
+1) Use it for a while, as a client, as a relay, as a hidden service,
+and as a directory authority. See if it has any obvious bugs, and
+resolve those.
+
+1.5) As applicable, merge the maint-X branch into the release-X branch.
+
+2) Gather the changes/* files into a changelog entry, rewriting many
+of them and reordering to focus on what users and funders would find
+interesting and understandable.
+
+ 2.1) Make sure that everything that wants a bug number has one.
+ Make sure that everything which is a bugfix says what version
+ it was a bugfix on.
+ 2.2) Concatenate them.
+ 2.3) Sort them by section. Within each section, sort by "version it's
+ a bugfix on", else by numerical ticket order.
+
+ 2.4) Clean them up:
+
+ Standard idioms:
+ "Fixes bug 9999; bugfix on 0.3.3.3-alpha."
+
+ One space after a period.
+
+ Make stuff very terse
+
+ Make sure each section name ends with a colon
+
+ Describe the user-visible problem right away
+
+ Mention relevant config options by name. If they're rare or unusual,
+ remind people what they're for
+
+ Avoid starting lines with open-paren
+
+ Present and imperative tense: not past.
+
+ 'Relays', not 'servers' or 'nodes' or 'Tor relays'.
+
+ "Stop FOOing", not "Fix a bug where we would FOO".
+
+ Try not to let any given section be longer than about a page. Break up
+ long sections into subsections by some sort of common subtopic. This
+ guideline is especially important when organizing Release Notes for
+ new stable releases.
+
+ If a given changes stanza showed up in a different release (e.g.
+ maint-0.2.1), be sure to make the stanzas identical (so people can
+ distinguish if these are the same change).
+
+ 2.5) Merge them in.
+
+ 2.6) Clean everything one last time.
+
+ 2.7) Run ./scripts/maint/format_changelog.py to make it prettier.
+
+3) Compose a short release blurb to highlight the user-facing
+changes. Insert said release blurb into the ChangeLog stanza. If it's
+a stable release, add it to the ReleaseNotes file too. If we're adding
+to a release-0.2.x branch, manually commit the changelogs to the later
+git branches too.
+
+4) In maint-0.2.x, bump the version number in configure.ac and run
+ scripts/maint/updateVersions.pl to update version numbers in other
+ places, and commit. Then merge maint-0.2.x into release-0.2.x.
+
+ (NOTE: TO bump the version number, edit configure.ac, and then run
+ either make, or 'perl scripts/maint/updateVersions.pl', depending on
+ your version.)
+
+5) Make dist, put the tarball up somewhere, and tell #tor about it. Wait
+a while to see if anybody has problems building it. Try to get Sebastian
+or somebody to try building it on Windows.
+
+6) Get at least two of weasel/arma/sebastian to put the new version number
+in their approved versions list.
+
+7) Sign the tarball, then sign and push the git tag:
+ gpg -ba <the_tarball>
+ git tag -u <keyid> tor-0.2.x.y-status
+ git push origin tag tor-0.2.x.y-status
+
+8a) scp the tarball and its sig to the dist website, i.e.
+/srv/dist-master.torproject.org/htdocs/ on dist-master. When you want
+it to go live, you run "static-update-component dist.torproject.org"
+on dist-master.
+
+8b) Edit "include/versions.wmi" and "Makefile" to note the new version.
+
+9) Email the packagers (cc'ing tor-assistants) that a new tarball is up.
+ The current list of packagers is:
+ {weasel,gk,mikeperry} at torproject dot org
+ {blueness} at gentoo dot org
+ {paul} at invizbox dot io
+ {ondrej.mikle} at gmail dot com
+ {lfleischer} at archlinux dot org
+
+10) Add the version number to Trac. To do this, go to Trac, log in,
+select "Admin" near the top of the screen, then select "Versions" from
+the menu on the left. At the right, there will be an "Add version"
+box. By convention, we enter the version in the form "Tor:
+0.2.2.23-alpha" (or whatever the version is), and we select the date as
+the date in the ChangeLog.
+
+11) Forward-port the ChangeLog.
+
+12) Wait up to a day or two (for a development release), or until most
+packages are up (for a stable release), and mail the release blurb and
+changelog to tor-talk or tor-announce.
+
+ (We might be moving to faster announcements, but don't announce until
+ the website is at least updated.)
+
+13) If it's a stable release, bump the version number in the maint-x.y.z
+ branch to "newversion-dev", and do a "merge -s ours" merge to avoid
+ taking that change into master. Do a similar 'merge -s theirs'
+ merge to get the change (and only that change) into release. (Some
+ of the build scripts require that maint merge cleanly into release.)
+
diff --git a/doc/HACKING/WritingTests.txt b/doc/HACKING/WritingTests.txt
new file mode 100644
index 0000000..977b836
--- /dev/null
+++ b/doc/HACKING/WritingTests.txt
@@ -0,0 +1,401 @@
+
+Writing tests for Tor: an incomplete guide
+==========================================
+
+Tor uses a variety of testing frameworks and methodologies to try to
+keep from introducing bugs. The major ones are:
+
+ 1. Unit tests written in C and shipped with the Tor distribution.
+
+ 2. Integration tests written in Python and shipped with the Tor
+ distribution.
+
+ 3. Integration tests written in Python and shipped with the Stem
+ library. Some of these use the Tor controller protocol.
+
+ 4. System tests written in Python and SH, and shipped with the
+ Chutney package. These work by running many instances of Tor
+ locally, and sending traffic through them.
+
+ 5. The Shadow network simulator.
+
+How to run these tests
+----------------------
+
+=== The easy version
+
+To run all the tests that come bundled with Tor, run "make check"
+
+To run the Stem tests as well, fetch stem from the git repository,
+set STEM_SOURCE_DIR to the checkout, and run "make test-stem".
+
+To run the Chutney tests as well, fetch chutney from the git repository,
+set CHUTNEY_PATH to the checkout, and run "make test-network".
+
+To run all of the above, run "make test-full".
+
+To run all of the above, plus tests that require a working connection to the
+internet, run "make test-full-online".
+
+=== Running particular subtests
+
+The Tor unit tests are divided into separate programs and a couple of
+bundled unit test programs.
+
+Separate programs are easy. For example, to run the memwipe tests in
+isolation, you just run ./src/test/test-memwipe .
+
+To run tests within the unit test programs, you can specify the name
+of the test. The string ".." can be used as a wildcard at the end of the
+test name. For example, to run all the cell format tests, enter
+"./src/test/test cellfmt/..". To run
+
+Many tests that need to mess with global state run in forked subprocesses in
+order to keep from contaminating one another. But when debugging a failing test,
+you might want to run it without forking a subprocess. To do so, use the
+"--no-fork" option with a single test. (If you specify it along with
+multiple tests, they might interfere.)
+
+You can turn on logging in the unit tests by passing one of "--debug",
+"--info", "--notice", or "--warn". By default only errors are displayed.
+
+Unit tests are divided into "./src/test/test" and "./src/test/test-slow".
+The former are those that should finish in a few seconds; the latter tend to
+take more time, and may include CPU-intensive operations, deliberate delays,
+and stuff like that.
+
+=== Finding test coverage
+
+Test coverage is a measurement of which lines your tests actually visit.
+
+When you configure Tor with the --enable-coverage option, it should
+build with support for coverage in the unit tests, and in a special
+"tor-cov" binary.
+
+Then, run the tests you'd like to see coverage from. If you have old
+coverage output, you may need to run "reset-gcov" first.
+
+Now you've got a bunch of files scattered around your build directories
+called "*.gcda". In order to extract the coverage output from them, make a
+temporary directory for them and run "./scripts/test/coverage ${TMPDIR}",
+where ${TMPDIR} is the temporary directory you made. This will create a
+".gcov" file for each source file under tests, containing that file's source
+annotated with the number of times the tests hit each line. (You'll need to
+have gcov installed.)
+
+You can get a summary of the test coverage for each file by running
+"./scripts/test/cov-display ${TMPDIR}/*" . Each line lists the file's name,
+the number of uncovered lines, the number of uncovered lines, and the
+coverage percentage.
+
+For a summary of the test coverage for each _function_, run
+"./scripts/test/cov-display -f ${TMPDIR}/*" .
+
+=== Comparing test coverage
+
+Sometimes it's useful to compare test coverage for a branch you're writing to
+coverage from another branch (such as git master, for example). But you
+can't run "diff" on the two coverage outputs directly, since the actual
+number of times each line is executed aren't so important, and aren't wholly
+deterministic.
+
+Instead, follow the instructions above for each branch, creating a separate
+temporary directory for each. Then, run "./scripts/test/cov-diff ${D1}
+${D2}", where D1 and D2 are the directories you want to compare. This will
+produce a diff of the two directories, with all lines normalized to be either
+covered or uncovered.
+
+To count new or modified uncovered lines in D2, you can run:
+
+ "./scripts/test/cov-diff ${D1} ${D2}" | grep '^+ *\#' |wc -l
+
+
+What kinds of test should I write?
+----------------------------------
+
+Integration testing and unit testing are complementary: it's probably a
+good idea to make sure that your code is hit by both if you can.
+
+If your code is very-low level, and its behavior is easily described in
+terms of a relation between inputs and outputs, or a set of state
+transitions, then it's a natural fit for unit tests. (If not, please
+consider refactoring it until most of it _is_ a good fit for unit
+tests!)
+
+If your code adds new externally visible functionality to Tor, it would
+be great to have a test for that functionality. That's where
+integration tests more usually come in.
+
+Unit and regression tests: Does this function do what it's supposed to?
+-----------------------------------------------------------------------
+
+Most of Tor's unit tests are made using the "tinytest" testing framework.
+You can see a guide to using it in the tinytest manual at
+
+ https://github.com/nmathewson/tinytest/blob/master/tinytest-manual.md
+
+To add a new test of this kind, either edit an existing C file in src/test/,
+or create a new C file there. Each test is a single function that must
+be indexed in the table at the end of the file. We use the label "done:" as
+a cleanup point for all test functions.
+
+(Make sure you read tinytest-manual.md before proceeding.)
+
+I use the term "unit test" and "regression tests" very sloppily here.
+
+=== A simple example
+
+Here's an example of a test function for a simple function in util.c:
+
+ static void
+ test_util_writepid(void *arg)
+ {
+ (void) arg;
+
+ char *contents = NULL;
+ const char *fname = get_fname("tmp_pid");
+ unsigned long pid;
+ char c;
+
+ write_pidfile(fname);
+
+ contents = read_file_to_str(fname, 0, NULL);
+ tt_assert(contents);
+
+ int n = sscanf(contents, "%lu\n%c", &pid, &c);
+ tt_int_op(n, OP_EQ, 1);
+ tt_int_op(pid, OP_EQ, getpid());
+
+ done:
+ tor_free(contents);
+ }
+
+This should look pretty familiar to you if you've read the tinytest
+manual. One thing to note here is that we use the testing-specific
+function "get_fname" to generate a file with respect to a temporary
+directory that the tests use. You don't need to delete the file;
+it will get removed when the tests are done.
+
+Also note our use of OP_EQ instead of == in the tt_int_op() calls.
+We define OP_* macros to use instead of the binary comparison
+operators so that analysis tools can more easily parse our code.
+(Coccinelle really hates to see == used as a macro argument.)
+
+Finally, remember that by convention, all *_free() functions that
+Tor defines are defined to accept NULL harmlessly. Thus, you don't
+need to say "if (contents)" in the cleanup block.
+
+=== Exposing static functions for testing
+
+Sometimes you need to test a function, but you don't want to expose
+it outside its usual module.
+
+To support this, Tor's build system compiles a testing version of
+each module, with extra identifiers exposed. If you want to
+declare a function as static but available for testing, use the
+macro "STATIC" instead of "static". Then, make sure there's a
+macro-protected declaration of the function in the module's header.
+
+For example, crypto_curve25519.h contains:
+
+#ifdef CRYPTO_CURVE25519_PRIVATE
+STATIC int curve25519_impl(uint8_t *output, const uint8_t *secret,
+ const uint8_t *basepoint);
+#endif
+
+The crypto_curve25519.c file and the test_crypto.c file both define
+CRYPTO_CURVE25519_PRIVATE, so they can see this declaration.
+
+=== Mock functions for testing in isolation
+
+Often we want to test that a function works right, but the function to
+be tested depends on other functions whose behavior is hard to observe,
+or which require a working Tor network, or something like that.
+
+To write tests for this case, you can replace the underlying functions
+with testing stubs while your unit test is running. You need to declare
+the underlying function as 'mockable', as follows:
+
+ MOCK_DECL(returntype, functionname, (argument list));
+
+and then later implement it as:
+
+ MOCK_IMPL(returntype, functionname, (argument list))
+ {
+ /* implementation here */
+ }
+
+For example, if you had a 'connect to remote server' function, you could
+declare it as:
+
+
+ MOCK_DECL(int, connect_to_remote, (const char *name, status_t *status));
+
+When you declare a function this way, it will be declared as normal in
+regular builds, but when the module is built for testing, it is declared
+as a function pointer initialized to the actual implementation.
+
+In your tests, if you want to override the function with a temporary
+replacement, you say:
+
+ MOCK(functionname, replacement_function_name);
+
+And later, you can restore the original function with:
+
+ UNMOCK(functionname);
+
+For more information, see the definitions of this mocking logic in
+testsupport.h.
+
+=== Okay but what should my tests actually do?
+
+We talk above about "test coverage" -- making sure that your tests visit
+every line of code, or every branch of code. But visiting the code isn't
+enough: we want to verify that it's correct.
+
+So when writing tests, try to make tests that should pass with any correct
+implementation of the code, and that should fail if the code doesn't do what
+it's supposed to do.
+
+You can write "black-box" tests or "glass-box" tests. A black-box test is
+one that you write without looking at the structure of the function. A
+glass-box one is one you implement while looking at how the function is
+implemented.
+
+In either case, make sure to consider common cases *and* edge cases; success
+cases and failure csaes.
+
+For example, consider testing this function:
+
+ /** Remove all elements E from sl such that E==element. Preserve
+ * the order of any elements before E, but elements after E can be
+ * rearranged.
+ */
+ void smartlist_remove(smartlist_t *sl, const void *element);
+
+In order to test it well, you should write tests for at least all of the
+following cases. (These would be black-box tests, since we're only looking
+at the declared behavior for the function:
+
+ * Remove an element that is in the smartlist.
+ * Remove an element that is not in the smartlist.
+ * Remove an element that appears in the smartlist more than once.
+
+And your tests should verify that it behaves correct. At minimum, you should
+test:
+
+ * That other elements before E are in the same order after you call the
+ functions.
+ * That the target element is really removed.
+ * That _only_ the target element is removed.
+
+When you consider edge cases, you might try:
+
+ * Remove an element from an empty list.
+ * Remove an element from a singleton list containing that element.
+ * Remove an element for a list containing several instances of that
+ element, and nothing else.
+
+Now let's look at the implementation:
+
+ void
+ smartlist_remove(smartlist_t *sl, const void *element)
+ {
+ int i;
+ if (element == NULL)
+ return;
+ for (i=0; i < sl->num_used; i++)
+ if (sl->list[i] == element) {
+ sl->list[i] = sl->list[--sl->num_used]; /* swap with the end */
+ i--; /* so we process the new i'th element */
+ sl->list[sl->num_used] = NULL;
+ }
+ }
+
+Based on the implementation, we now see three more edge cases to test:
+
+ * Removing NULL from the list.
+ * Removing an element from the end of the list
+ * Removing an element from a position other than the end of the list.
+
+
+=== What should my tests NOT do?
+
+Tests shouldn't require a network connection.
+
+Whenever possible, tests shouldn't take more than a second. Put the test
+into test/slow if it genuinely needs to be run.
+
+Tests should not alter global state unless they run with TT_FORK: Tests
+should not require other tests to be run before or after them.
+
+Tests should not leak memory or other resources.
+
+When possible, tests should not be over-fit to the implementation. That is,
+the test should verify that the documented behavior is implemented, but
+should not break if other permissible behavior is later implemented.
+
+
+=== Advanced techniques: Namespaces
+
+Sometimes, when you're doing a lot of mocking at once, it's convenient to
+isolate your identifiers within a single namespace. If this were C++, we'd
+already have namespaces, but for C, we do the best we can with macros and
+token-pasting.
+
+We have some macros defined for this purpose in src/test/test.h. To use
+them, you define NS_MODULE to a prefix to be used for your identifiers, and
+then use other macros in place of identifier names. See src/test/test.h for
+more documentation.
+
+
+Integration tests: Calling Tor from the outside
+-----------------------------------------------
+
+Some tests need to invoke Tor from the outside, and shouldn't run from the
+same process as the Tor test program. Reasons for doing this might include:
+
+ * Testing the actual behavior of Tor when run from the command line
+ * Testing that a crash-handler correctly logs a stack trace
+ * Verifying that a violating a sandbox or capability requirement will
+ actually crash the program.
+ * Needing to run as root in order to test capability inheritance or
+ user switching.
+
+To add one of these, you generally want a new C program in src/test. Add it
+to TESTS and noinst_PROGRAMS if it can run on its own and return success or
+failure. If it needs to be invoked multiple times, or it needs to be
+wrapped, add a new shell script to TESTS, and the new program to
+noinst_PROGRAMS. If you need access to any environment variable from the
+makefile (eg ${PYTHON} for a python interpreter), then make sure that the
+makefile exports them.
+
+Writing integration tests with Stem
+-----------------------------------
+
+The 'stem' library includes extensive unit tests for the Tor controller
+protocol.
+
+For more information on writing new tests for stem, have a look around
+the tst/* directory in stem, and find a good example to emulate. You
+might want to start with
+https://gitweb.torproject.org/stem.git/tree/test/integ/control/controller.py
+to improve Tor's test coverage.
+
+You can run stem tests from tor with "make test-stem", or see
+https://stem.torproject.org/faq.html#how-do-i-run-the-tests .
+
+System testing with Chutney
+---------------------------
+
+The 'chutney' program configures and launches a set of Tor relays,
+authorities, and clients on your local host. It has a 'test network'
+functionality to send traffic through them and verify that the traffic
+arrives correctly.
+
+You can write new test networks by adding them to 'networks'. To add
+them to Tor's tests, add them to the test-network or test-network-all
+targets in Makefile.am.
+
+(Adding new kinds of program to chutney will still require hacking the
+code.)
diff --git a/doc/WritingTests.txt b/doc/WritingTests.txt
deleted file mode 100644
index 977b836..0000000
--- a/doc/WritingTests.txt
+++ /dev/null
@@ -1,401 +0,0 @@
-
-Writing tests for Tor: an incomplete guide
-==========================================
-
-Tor uses a variety of testing frameworks and methodologies to try to
-keep from introducing bugs. The major ones are:
-
- 1. Unit tests written in C and shipped with the Tor distribution.
-
- 2. Integration tests written in Python and shipped with the Tor
- distribution.
-
- 3. Integration tests written in Python and shipped with the Stem
- library. Some of these use the Tor controller protocol.
-
- 4. System tests written in Python and SH, and shipped with the
- Chutney package. These work by running many instances of Tor
- locally, and sending traffic through them.
-
- 5. The Shadow network simulator.
-
-How to run these tests
-----------------------
-
-=== The easy version
-
-To run all the tests that come bundled with Tor, run "make check"
-
-To run the Stem tests as well, fetch stem from the git repository,
-set STEM_SOURCE_DIR to the checkout, and run "make test-stem".
-
-To run the Chutney tests as well, fetch chutney from the git repository,
-set CHUTNEY_PATH to the checkout, and run "make test-network".
-
-To run all of the above, run "make test-full".
-
-To run all of the above, plus tests that require a working connection to the
-internet, run "make test-full-online".
-
-=== Running particular subtests
-
-The Tor unit tests are divided into separate programs and a couple of
-bundled unit test programs.
-
-Separate programs are easy. For example, to run the memwipe tests in
-isolation, you just run ./src/test/test-memwipe .
-
-To run tests within the unit test programs, you can specify the name
-of the test. The string ".." can be used as a wildcard at the end of the
-test name. For example, to run all the cell format tests, enter
-"./src/test/test cellfmt/..". To run
-
-Many tests that need to mess with global state run in forked subprocesses in
-order to keep from contaminating one another. But when debugging a failing test,
-you might want to run it without forking a subprocess. To do so, use the
-"--no-fork" option with a single test. (If you specify it along with
-multiple tests, they might interfere.)
-
-You can turn on logging in the unit tests by passing one of "--debug",
-"--info", "--notice", or "--warn". By default only errors are displayed.
-
-Unit tests are divided into "./src/test/test" and "./src/test/test-slow".
-The former are those that should finish in a few seconds; the latter tend to
-take more time, and may include CPU-intensive operations, deliberate delays,
-and stuff like that.
-
-=== Finding test coverage
-
-Test coverage is a measurement of which lines your tests actually visit.
-
-When you configure Tor with the --enable-coverage option, it should
-build with support for coverage in the unit tests, and in a special
-"tor-cov" binary.
-
-Then, run the tests you'd like to see coverage from. If you have old
-coverage output, you may need to run "reset-gcov" first.
-
-Now you've got a bunch of files scattered around your build directories
-called "*.gcda". In order to extract the coverage output from them, make a
-temporary directory for them and run "./scripts/test/coverage ${TMPDIR}",
-where ${TMPDIR} is the temporary directory you made. This will create a
-".gcov" file for each source file under tests, containing that file's source
-annotated with the number of times the tests hit each line. (You'll need to
-have gcov installed.)
-
-You can get a summary of the test coverage for each file by running
-"./scripts/test/cov-display ${TMPDIR}/*" . Each line lists the file's name,
-the number of uncovered lines, the number of uncovered lines, and the
-coverage percentage.
-
-For a summary of the test coverage for each _function_, run
-"./scripts/test/cov-display -f ${TMPDIR}/*" .
-
-=== Comparing test coverage
-
-Sometimes it's useful to compare test coverage for a branch you're writing to
-coverage from another branch (such as git master, for example). But you
-can't run "diff" on the two coverage outputs directly, since the actual
-number of times each line is executed aren't so important, and aren't wholly
-deterministic.
-
-Instead, follow the instructions above for each branch, creating a separate
-temporary directory for each. Then, run "./scripts/test/cov-diff ${D1}
-${D2}", where D1 and D2 are the directories you want to compare. This will
-produce a diff of the two directories, with all lines normalized to be either
-covered or uncovered.
-
-To count new or modified uncovered lines in D2, you can run:
-
- "./scripts/test/cov-diff ${D1} ${D2}" | grep '^+ *\#' |wc -l
-
-
-What kinds of test should I write?
-----------------------------------
-
-Integration testing and unit testing are complementary: it's probably a
-good idea to make sure that your code is hit by both if you can.
-
-If your code is very-low level, and its behavior is easily described in
-terms of a relation between inputs and outputs, or a set of state
-transitions, then it's a natural fit for unit tests. (If not, please
-consider refactoring it until most of it _is_ a good fit for unit
-tests!)
-
-If your code adds new externally visible functionality to Tor, it would
-be great to have a test for that functionality. That's where
-integration tests more usually come in.
-
-Unit and regression tests: Does this function do what it's supposed to?
------------------------------------------------------------------------
-
-Most of Tor's unit tests are made using the "tinytest" testing framework.
-You can see a guide to using it in the tinytest manual at
-
- https://github.com/nmathewson/tinytest/blob/master/tinytest-manual.md
-
-To add a new test of this kind, either edit an existing C file in src/test/,
-or create a new C file there. Each test is a single function that must
-be indexed in the table at the end of the file. We use the label "done:" as
-a cleanup point for all test functions.
-
-(Make sure you read tinytest-manual.md before proceeding.)
-
-I use the term "unit test" and "regression tests" very sloppily here.
-
-=== A simple example
-
-Here's an example of a test function for a simple function in util.c:
-
- static void
- test_util_writepid(void *arg)
- {
- (void) arg;
-
- char *contents = NULL;
- const char *fname = get_fname("tmp_pid");
- unsigned long pid;
- char c;
-
- write_pidfile(fname);
-
- contents = read_file_to_str(fname, 0, NULL);
- tt_assert(contents);
-
- int n = sscanf(contents, "%lu\n%c", &pid, &c);
- tt_int_op(n, OP_EQ, 1);
- tt_int_op(pid, OP_EQ, getpid());
-
- done:
- tor_free(contents);
- }
-
-This should look pretty familiar to you if you've read the tinytest
-manual. One thing to note here is that we use the testing-specific
-function "get_fname" to generate a file with respect to a temporary
-directory that the tests use. You don't need to delete the file;
-it will get removed when the tests are done.
-
-Also note our use of OP_EQ instead of == in the tt_int_op() calls.
-We define OP_* macros to use instead of the binary comparison
-operators so that analysis tools can more easily parse our code.
-(Coccinelle really hates to see == used as a macro argument.)
-
-Finally, remember that by convention, all *_free() functions that
-Tor defines are defined to accept NULL harmlessly. Thus, you don't
-need to say "if (contents)" in the cleanup block.
-
-=== Exposing static functions for testing
-
-Sometimes you need to test a function, but you don't want to expose
-it outside its usual module.
-
-To support this, Tor's build system compiles a testing version of
-each module, with extra identifiers exposed. If you want to
-declare a function as static but available for testing, use the
-macro "STATIC" instead of "static". Then, make sure there's a
-macro-protected declaration of the function in the module's header.
-
-For example, crypto_curve25519.h contains:
-
-#ifdef CRYPTO_CURVE25519_PRIVATE
-STATIC int curve25519_impl(uint8_t *output, const uint8_t *secret,
- const uint8_t *basepoint);
-#endif
-
-The crypto_curve25519.c file and the test_crypto.c file both define
-CRYPTO_CURVE25519_PRIVATE, so they can see this declaration.
-
-=== Mock functions for testing in isolation
-
-Often we want to test that a function works right, but the function to
-be tested depends on other functions whose behavior is hard to observe,
-or which require a working Tor network, or something like that.
-
-To write tests for this case, you can replace the underlying functions
-with testing stubs while your unit test is running. You need to declare
-the underlying function as 'mockable', as follows:
-
- MOCK_DECL(returntype, functionname, (argument list));
-
-and then later implement it as:
-
- MOCK_IMPL(returntype, functionname, (argument list))
- {
- /* implementation here */
- }
-
-For example, if you had a 'connect to remote server' function, you could
-declare it as:
-
-
- MOCK_DECL(int, connect_to_remote, (const char *name, status_t *status));
-
-When you declare a function this way, it will be declared as normal in
-regular builds, but when the module is built for testing, it is declared
-as a function pointer initialized to the actual implementation.
-
-In your tests, if you want to override the function with a temporary
-replacement, you say:
-
- MOCK(functionname, replacement_function_name);
-
-And later, you can restore the original function with:
-
- UNMOCK(functionname);
-
-For more information, see the definitions of this mocking logic in
-testsupport.h.
-
-=== Okay but what should my tests actually do?
-
-We talk above about "test coverage" -- making sure that your tests visit
-every line of code, or every branch of code. But visiting the code isn't
-enough: we want to verify that it's correct.
-
-So when writing tests, try to make tests that should pass with any correct
-implementation of the code, and that should fail if the code doesn't do what
-it's supposed to do.
-
-You can write "black-box" tests or "glass-box" tests. A black-box test is
-one that you write without looking at the structure of the function. A
-glass-box one is one you implement while looking at how the function is
-implemented.
-
-In either case, make sure to consider common cases *and* edge cases; success
-cases and failure csaes.
-
-For example, consider testing this function:
-
- /** Remove all elements E from sl such that E==element. Preserve
- * the order of any elements before E, but elements after E can be
- * rearranged.
- */
- void smartlist_remove(smartlist_t *sl, const void *element);
-
-In order to test it well, you should write tests for at least all of the
-following cases. (These would be black-box tests, since we're only looking
-at the declared behavior for the function:
-
- * Remove an element that is in the smartlist.
- * Remove an element that is not in the smartlist.
- * Remove an element that appears in the smartlist more than once.
-
-And your tests should verify that it behaves correct. At minimum, you should
-test:
-
- * That other elements before E are in the same order after you call the
- functions.
- * That the target element is really removed.
- * That _only_ the target element is removed.
-
-When you consider edge cases, you might try:
-
- * Remove an element from an empty list.
- * Remove an element from a singleton list containing that element.
- * Remove an element for a list containing several instances of that
- element, and nothing else.
-
-Now let's look at the implementation:
-
- void
- smartlist_remove(smartlist_t *sl, const void *element)
- {
- int i;
- if (element == NULL)
- return;
- for (i=0; i < sl->num_used; i++)
- if (sl->list[i] == element) {
- sl->list[i] = sl->list[--sl->num_used]; /* swap with the end */
- i--; /* so we process the new i'th element */
- sl->list[sl->num_used] = NULL;
- }
- }
-
-Based on the implementation, we now see three more edge cases to test:
-
- * Removing NULL from the list.
- * Removing an element from the end of the list
- * Removing an element from a position other than the end of the list.
-
-
-=== What should my tests NOT do?
-
-Tests shouldn't require a network connection.
-
-Whenever possible, tests shouldn't take more than a second. Put the test
-into test/slow if it genuinely needs to be run.
-
-Tests should not alter global state unless they run with TT_FORK: Tests
-should not require other tests to be run before or after them.
-
-Tests should not leak memory or other resources.
-
-When possible, tests should not be over-fit to the implementation. That is,
-the test should verify that the documented behavior is implemented, but
-should not break if other permissible behavior is later implemented.
-
-
-=== Advanced techniques: Namespaces
-
-Sometimes, when you're doing a lot of mocking at once, it's convenient to
-isolate your identifiers within a single namespace. If this were C++, we'd
-already have namespaces, but for C, we do the best we can with macros and
-token-pasting.
-
-We have some macros defined for this purpose in src/test/test.h. To use
-them, you define NS_MODULE to a prefix to be used for your identifiers, and
-then use other macros in place of identifier names. See src/test/test.h for
-more documentation.
-
-
-Integration tests: Calling Tor from the outside
------------------------------------------------
-
-Some tests need to invoke Tor from the outside, and shouldn't run from the
-same process as the Tor test program. Reasons for doing this might include:
-
- * Testing the actual behavior of Tor when run from the command line
- * Testing that a crash-handler correctly logs a stack trace
- * Verifying that a violating a sandbox or capability requirement will
- actually crash the program.
- * Needing to run as root in order to test capability inheritance or
- user switching.
-
-To add one of these, you generally want a new C program in src/test. Add it
-to TESTS and noinst_PROGRAMS if it can run on its own and return success or
-failure. If it needs to be invoked multiple times, or it needs to be
-wrapped, add a new shell script to TESTS, and the new program to
-noinst_PROGRAMS. If you need access to any environment variable from the
-makefile (eg ${PYTHON} for a python interpreter), then make sure that the
-makefile exports them.
-
-Writing integration tests with Stem
------------------------------------
-
-The 'stem' library includes extensive unit tests for the Tor controller
-protocol.
-
-For more information on writing new tests for stem, have a look around
-the tst/* directory in stem, and find a good example to emulate. You
-might want to start with
-https://gitweb.torproject.org/stem.git/tree/test/integ/control/controller.py
-to improve Tor's test coverage.
-
-You can run stem tests from tor with "make test-stem", or see
-https://stem.torproject.org/faq.html#how-do-i-run-the-tests .
-
-System testing with Chutney
----------------------------
-
-The 'chutney' program configures and launches a set of Tor relays,
-authorities, and clients on your local host. It has a 'test network'
-functionality to send traffic through them and verify that the traffic
-arrives correctly.
-
-You can write new test networks by adding them to 'networks'. To add
-them to Tor's tests, add them to the test-network or test-network-all
-targets in Makefile.am.
-
-(Adding new kinds of program to chutney will still require hacking the
-code.)
diff --git a/doc/include.am b/doc/include.am
index f33103b..5decfe5 100644
--- a/doc/include.am
+++ b/doc/include.am
@@ -34,13 +34,14 @@ nodist_man1_MANS =
doc_DATA =
endif
-EXTRA_DIST+= doc/HACKING doc/asciidoc-helper.sh \
+EXTRA_DIST+= doc/asciidoc-helper.sh \
$(html_in) $(man_in) $(txt_in) \
doc/state-contents.txt \
doc/torrc_format.txt \
doc/TUNING \
- doc/WritingTests.txt \
- doc/GettingStarted.txt
+ doc/HACKING/WritingTests.txt \
+ doc/HACKING/GettingStarted.txt \
+ doc/HACKING/HACKING_old
docdir = @docdir@
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