diff options
Diffstat (limited to 'doc/HACKING/CodeStructure.md')
| -rw-r--r-- | doc/HACKING/CodeStructure.md | 152 |
1 files changed, 73 insertions, 79 deletions
diff --git a/doc/HACKING/CodeStructure.md b/doc/HACKING/CodeStructure.md index 736d6cd484..d387018f9b 100644 --- a/doc/HACKING/CodeStructure.md +++ b/doc/HACKING/CodeStructure.md @@ -1,129 +1,123 @@ +# Code Structure TODO: revise this to talk about how things are, rather than how things have changed. -TODO: Make this into good markdown. - - - -For quite a while now, the program "tor" has been built from source -code in just two directories: src/common and src/or. +For quite a while now, the program *tor* has been built from source +code in just two directories: **src/common** and **src/or**. This has become more-or-less untenable, for a few reasons -- most notably of which is that it has led our code to become more spaghetti-ish than I can endorse with a clean conscience. So to fix that, we've gone and done a huge code movement in our git -master branch, which will land in a release once Tor 0.3.5.1-alpha is +master branch, which will land in a release once Tor `0.3.5.1-alpha` is out. Here's what we did: - * src/common has been turned into a set of static libraries. These -all live in the "src/lib/*" directories. The dependencies between + * **src/common** has been turned into a set of static libraries. These +all live in the **src/lib/*** directories. The dependencies between these libraries should have no cycles. The libraries are: - arch -- Headers to handle architectural differences - cc -- headers to handle differences among compilers - compress -- wraps zlib, zstd, lzma - container -- high-level container types - crypt_ops -- Cryptographic operations. Planning to split this into + - **arch** -- Headers to handle architectural differences + - **cc** -- headers to handle differences among compilers + - **compress** -- wraps zlib, zstd, lzma + - **container** -- high-level container types + - **crypt_ops** -- Cryptographic operations. Planning to split this into a higher and lower level library - ctime -- Operations that need to run in constant-time. (Properly, + - **ctime** -- Operations that need to run in constant-time. (Properly, data-invariant time) - defs -- miscelaneous definitions needed throughout Tor. - encoding -- transforming one data type into another, and various + - **defs** -- miscelaneous definitions needed throughout Tor. + - **encoding** -- transforming one data type into another, and various data types into strings. - err -- lowest-level error handling, in cases where we can't use + - **err** -- lowest-level error handling, in cases where we can't use the logs because something that the logging system needs has broken. - evloop -- Generic event-loop handling logic - fdio -- Low-level IO wrapper functions for file descriptors. - fs -- Operations on the filesystem - intmath -- low-level integer math and misc bit-twiddling hacks - lock -- low-level locking code - log -- Tor's logging module. This library sits roughly halfway up + - **evloop** -- Generic event-loop handling logic + - **fdio** -- Low-level IO wrapper functions for file descriptors. + - **fs** -- Operations on the filesystem + - **intmath** -- low-level integer math and misc bit-twiddling hacks + - **lock** -- low-level locking code + - **log** -- Tor's logging module. This library sits roughly halfway up the library dependency diagram, since everything it depends on has to be carefully crafted to *not* log. - malloc -- Low-level wrappers for the platform memory allocation functions. - math -- Higher-level mathematical functions, and floating-point math - memarea -- An arena allocator - meminfo -- Functions for querying the current process's memory + - **malloc** -- Low-level wrappers for the platform memory allocation functions. + - **math** -- Higher-level mathematical functions, and floating-point math + - **memarea** -- An arena allocator + - **meminfo** -- Functions for querying the current process's memory status and resources - net -- Networking compatibility and convenience code - osinfo -- Querying information about the operating system - process -- Launching and querying the status of other processes - sandbox -- Backend for the linux seccomp2 sandbox - smartlist_core -- The lowest-level of the smartlist_t data type. + - **net** -- Networking compatibility and convenience code + - **osinfo** -- Querying information about the operating system + - **process** -- Launching and querying the status of other processes + - **sandbox** -- Backend for the linux seccomp2 sandbox + - **smartlist_core** -- The lowest-level of the smartlist_t data type. Separated from the rest of the containers library because the logging subsystem depends on it. - string -- Compatibility and convenience functions for manipulating + - **string** -- Compatibility and convenience functions for manipulating C strings. - term -- Terminal-related functions (currently limited to a getpass + - **term** -- Terminal-related functions (currently limited to a getpass function). - testsupport -- Macros for mocking, unit tests, etc. - thread -- Higher-level thread compatibility code - time -- Higher-level time management code, including format + - **testsupport** -- Macros for mocking, unit tests, etc. + - **thread** -- Higher-level thread compatibility code + - **time** -- Higher-level time management code, including format conversions and monotonic time - tls -- Our wrapper around our TLS library - trace -- Formerly src/trace -- a generic event tracing API - wallclock -- Low-level time code, used by the log module. + - **tls** -- Our wrapper around our TLS library + - **trace** -- Formerly src/trace -- a generic event tracing API + - **wallclock** -- Low-level time code, used by the log module. - * To ensure that the dependency graph in src/common remains under -control, there is a tool that you can run called "make -check-includes". It verifies that each module in Tor only includes + * To ensure that the dependency graph in **src/common** remains under +control, there is a tool that you can run called `make +check-includes`. It verifies that each module in Tor only includes the headers that it is permitted to include, using a per-directory -".may_include" file. +*.may_include* file. - * The src/or/or.h header has been split into numerous smaller + * The **src/or/or.h** header has been split into numerous smaller headers. Notably, many important structures are now declared in a -header called foo_st.h, where "foo" is the name of the structure. +header called *foo_st.h*, where "foo" is the name of the structure. - * The src/or directory, which had most of Tor's code, had been split + * The **src/or** directory, which had most of Tor's code, had been split up into several directories. This is still a work in progress: This code has not itself been refactored, and its dependency graph is still a tangled web. I hope we'll be working on that over the coming releases, but it will take a while to do. - The new top-level source directories are: - - src/core -- Code necessary to actually perform or use onion routing. - src/feature -- Code used only by some onion routing + - The new top-level source directories are: + - **src/core** -- Code necessary to actually perform or use onion routing. + - **src/feature** -- Code used only by some onion routing configurations, or only for a special purpose. - src/app -- Top-level code to run, invoke, and configure the + - **src/app** -- Top-level code to run, invoke, and configure the lower-level code - The new second-level source directories are: - src/core/crypto -- High-level cryptographic protocols used in Tor - src/core/mainloop -- Tor's event loop, connection-handling, and + - The new second-level source directories are: + - **src/core/crypto** -- High-level cryptographic protocols used in Tor + - **src/core/mainloop** -- Tor's event loop, connection-handling, and traffic-routing code. - src/core/or -- Parts related to handling onion routing itself - src/core/proto -- support for encoding and decoding different + - **src/core/or** -- Parts related to handling onion routing itself + - **src/core/proto** -- support for encoding and decoding different wire protocols - - src/feature/api -- Support for making Tor embeddable - src/feature/client -- Functionality which only Tor clients need - src/feature/control -- Controller implementation - src/feature/dirauth -- Directory authority - src/feature/dircache -- Directory cache - src/feature/dirclient -- Directory client - src/feature/dircommon -- Shared code between the other directory modules - src/feature/hibernate -- Hibernating when Tor is out of bandwidth + - **src/feature/api** -- Support for making Tor embeddable + - **src/feature/client** -- Functionality which only Tor clients need + - **src/feature/control** -- Controller implementation + - **src/feature/dirauth** -- Directory authority + - **src/feature/dircache** -- Directory cache + - **src/feature/dirclient** -- Directory client + - **src/feature/dircommon** -- Shared code between the other directory modules + - **src/feature/hibernate** -- Hibernating when Tor is out of bandwidth or shutting down - src/feature/hs -- v3 onion service implementation - src/feature/hs_common -- shared code between both onion service + - **src/feature/hs** -- v3 onion service implementation + - **src/feature/hs_common** -- shared code between both onion service implementations - src/feature/nodelist -- storing and accessing the list of relays on + - **src/feature/nodelist** -- storing and accessing the list of relays on the network. - src/feature/relay -- code that only relay servers and exit servers need. - src/feature/rend -- v2 onion service implementation - src/feature/stats -- statistics and history - - src/app/config -- configuration and state for Tor - src/app/main -- Top-level functions to invoke the rest or Tor. + - **src/feature/relay** -- code that only relay servers and exit servers need. + - **src/feature/rend** -- v2 onion service implementation + - **src/feature/stats** -- statistics and history + - **src/app/config** -- configuration and state for Tor + - **src/app/main** -- Top-level functions to invoke the rest or Tor. - * The "tor" executable is now built in src/app/tor rather than src/or/tor. + * The `tor` executable is now built in **src/app/tor** rather than **src/or/tor**. * There are more static libraries than before that you need to build into your application if you want to embed Tor. Rather than -maintaining this list yourself, I recommend that you run "make -show-libs" to have Tor emit a list of what you need to link. +maintaining this list yourself, I recommend that you run `make +show-libs` to have Tor emit a list of what you need to link. |