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294 lines
9.3 KiB
Markdown
294 lines
9.3 KiB
Markdown
Useful tools
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============
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These aren't strictly necessary for hacking on Tor, but they can help track
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down bugs.
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Jenkins
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-------
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https://jenkins.torproject.org
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Dmalloc
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-------
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The dmalloc library will keep track of memory allocation, so you can find out
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if we're leaking memory, doing any double-frees, or so on.
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dmalloc -l -/dmalloc.log
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(run the commands it tells you)
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./configure --with-dmalloc
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Valgrind
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--------
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valgrind --leak-check=yes --error-limit=no --show-reachable=yes src/or/tor
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(Note that if you get a zillion openssl warnings, you will also need to
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pass `--undef-value-errors=no` to valgrind, or rebuild your openssl
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with `-DPURIFY`.)
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Coverity
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--------
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Nick regularly runs the coverity static analyzer on the Tor codebase.
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The preprocessor define `__COVERITY__` is used to work around instances
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where coverity picks up behavior that we wish to permit.
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clang Static Analyzer
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---------------------
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The clang static analyzer can be run on the Tor codebase using Xcode (WIP)
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or a command-line build.
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The preprocessor define `__clang_analyzer__` is used to work around instances
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where clang picks up behavior that we wish to permit.
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clang Runtime Sanitizers
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------------------------
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To build the Tor codebase with the clang Address and Undefined Behavior
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sanitizers, see the file `contrib/clang/sanitize_blacklist.txt`.
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Preprocessor workarounds for instances where clang picks up behavior that
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we wish to permit are also documented in the blacklist file.
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Running lcov for unit test coverage
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-----------------------------------
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Lcov is a utility that generates pretty HTML reports of test code coverage.
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To generate such a report:
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./configure --enable-coverage
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make
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make coverage-html
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$BROWSER ./coverage_html/index.html
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This will run the tor unit test suite `./src/test/test` and generate the HTML
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coverage code report under the directory `./coverage_html/`. To change the
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output directory, use `make coverage-html HTML_COVER_DIR=./funky_new_cov_dir`.
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Coverage diffs using lcov are not currently implemented, but are being
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investigated (as of July 2014).
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Running the unit tests
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----------------------
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To quickly run all the tests distributed with Tor:
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make check
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To run the fast unit tests only:
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make test
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To selectively run just some tests (the following can be combined
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arbitrarily):
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./src/test/test <name_of_test> [<name of test 2>] ...
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./src/test/test <prefix_of_name_of_test>.. [<prefix_of_name_of_test2>..] ...
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./src/test/test :<name_of_excluded_test> [:<name_of_excluded_test2]...
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To run all tests, including those based on Stem or Chutney:
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make test-full
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To run all tests, including those based on Stem or Chutney that require a
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working connection to the internet:
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make test-full-online
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Running gcov for unit test coverage
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-----------------------------------
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./configure --enable-coverage
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make
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make check
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# or--- make test-full ? make test-full-online?
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mkdir coverage-output
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./scripts/test/coverage coverage-output
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(On OSX, you'll need to start with `--enable-coverage CC=clang`.)
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Then, look at the .gcov files in `coverage-output`. '-' before a line means
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that the compiler generated no code for that line. '######' means that the
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line was never reached. Lines with numbers were called that number of times.
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If that doesn't work:
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* Try configuring Tor with `--disable-gcc-hardening`
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* You might need to run `make clean` after you run `./configure`.
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If you make changes to Tor and want to get another set of coverage results,
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you can run `make reset-gcov` to clear the intermediary gcov output.
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If you have two different `coverage-output` directories, and you want to see
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a meaningful diff between them, you can run:
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./scripts/test/cov-diff coverage-output1 coverage-output2 | less
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In this diff, any lines that were visited at least once will have coverage
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"1". This lets you inspect what you (probably) really want to know: which
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untested lines were changed? Are there any new untested lines?
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Running integration tests
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-------------------------
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We have the beginnings of a set of scripts to run integration tests using
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Chutney. To try them, set CHUTNEY_PATH to your chutney source directory, and
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run `make test-network`.
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We also have scripts to run integration tests using Stem. To try them, set
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`STEM_SOURCE_DIR` to your Stem source directory, and run `test-stem`.
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Profiling Tor with oprofile
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---------------------------
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The oprofile tool runs (on Linux only!) to tell you what functions Tor is
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spending its CPU time in, so we can identify performance bottlenecks.
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Here are some basic instructions
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- Build tor with debugging symbols (you probably already have, unless
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you messed with CFLAGS during the build process).
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- Build all the libraries you care about with debugging symbols
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(probably you only care about libssl, maybe zlib and Libevent).
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- Copy this tor to a new directory
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- Copy all the libraries it uses to that dir too (`ldd ./tor` will
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tell you)
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- Set LD_LIBRARY_PATH to include that dir. `ldd ./tor` should now
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show you it's using the libs in that dir
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- Run that tor
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- Reset oprofiles counters/start it
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* `opcontrol --reset; opcontrol --start`, if Nick remembers right.
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- After a while, have it dump the stats on tor and all the libs
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in that dir you created.
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* `opcontrol --dump;`
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* `opreport -l that_dir/*`
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- Profit
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Generating and analyzing a callgraph
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------------------------------------
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1. Run `./scripts/maint/generate_callgraph.sh`. This will generate a
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bunch of files in a new ./callgraph directory.
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2. Run `./scripts/maint/analyze_callgraph.py callgraph/src/*/*`. This
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will do a lot of graph operations and then dump out a new
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`callgraph.pkl` file, containing data in Python's 'pickle' format.
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3. Run `./scripts/maint/display_callgraph.py`. It will display:
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- the number of functions reachable from each function.
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- all strongly-connnected components in the Tor callgraph
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- the largest bottlenecks in the largest SCC in the Tor callgraph.
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Note that currently the callgraph generator can't detect calls that pass
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through function pointers.
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Getting emacs to edit Tor source properly
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-----------------------------------------
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Nick likes to put the following snippet in his .emacs file:
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(add-hook 'c-mode-hook
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(lambda ()
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(font-lock-mode 1)
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(set-variable 'show-trailing-whitespace t)
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(let ((fname (expand-file-name (buffer-file-name))))
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(cond
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((string-match "^/home/nickm/src/libevent" fname)
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(set-variable 'indent-tabs-mode t)
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(set-variable 'c-basic-offset 4)
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(set-variable 'tab-width 4))
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((string-match "^/home/nickm/src/tor" fname)
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(set-variable 'indent-tabs-mode nil)
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(set-variable 'c-basic-offset 2))
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((string-match "^/home/nickm/src/openssl" fname)
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(set-variable 'indent-tabs-mode t)
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(set-variable 'c-basic-offset 8)
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(set-variable 'tab-width 8))
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))))
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You'll note that it defaults to showing all trailing whitespace. The `cond`
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test detects whether the file is one of a few C free software projects that I
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often edit, and sets up the indentation level and tab preferences to match
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what they want.
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If you want to try this out, you'll need to change the filename regex
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patterns to match where you keep your Tor files.
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If you use emacs for editing Tor and nothing else, you could always just say:
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(add-hook 'c-mode-hook
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(lambda ()
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(font-lock-mode 1)
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(set-variable 'show-trailing-whitespace t)
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(set-variable 'indent-tabs-mode nil)
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(set-variable 'c-basic-offset 2)))
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There is probably a better way to do this. No, we are probably not going
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to clutter the files with emacs stuff.
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Doxygen
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-------
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We use the 'doxygen' utility to generate documentation from our
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source code. Here's how to use it:
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1. Begin every file that should be documented with
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/**
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* \file filename.c
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* \brief Short description of the file.
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*/
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(Doxygen will recognize any comment beginning with /** as special.)
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2. Before any function, structure, #define, or variable you want to
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document, add a comment of the form:
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/** Describe the function's actions in imperative sentences.
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*
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* Use blank lines for paragraph breaks
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* - and
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* - hyphens
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* - for
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* - lists.
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*
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* Write <b>argument_names</b> in boldface.
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*
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* \code
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* place_example_code();
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* between_code_and_endcode_commands();
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* \endcode
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*/
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3. Make sure to escape the characters `<`, `>`, `\`, `%` and `#` as `\<`,
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`\>`, `\\`, `\%` and `\#`.
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4. To document structure members, you can use two forms:
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struct foo {
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/** You can put the comment before an element; */
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int a;
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int b; /**< Or use the less-than symbol to put the comment
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* after the element. */
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};
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5. To generate documentation from the Tor source code, type:
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$ doxygen -g
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to generate a file called `Doxyfile`. Edit that file and run
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`doxygen` to generate the API documentation.
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6. See the Doxygen manual for more information; this summary just
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scratches the surface.
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