1 files changed, 50 insertions, 7 deletions
diff --git a/doc/HACKING/CodingStandards.md b/doc/HACKING/CodingStandards.md
index 2c273910d1..7999724166 100644
--- a/doc/HACKING/CodingStandards.md
+++ b/doc/HACKING/CodingStandards.md
@@ -219,6 +219,9 @@ deviations from our C whitespace style.  Generally, we use:
    - No space between a function name and an opening paren. `puts(x)`, not
      `puts (x)`.
    - Function declarations at the start of the line.
+   - Use `void foo(void)` to declare a function with no arguments.  Saying
+     `void foo()` is C++ syntax.
+   - Use `const` for new APIs.
 
 If you use an editor that has plugins for editorconfig.org, the file
 `.editorconfig` will help you to conform this coding style.
@@ -235,20 +238,49 @@ 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.)
 
+Specifically, Don't use `malloc`, `realloc`, `calloc`, `free`, or
+`strdup`. Use `tor_malloc`, `tor_realloc`, `tor_calloc`, `tor_free`, or
+`tor_strdup`.
+
+Don't use `tor_realloc(x, y\*z)`. Use `tor_reallocarray(x, y, z)` instead.;
+
 You can get a full list of the compatibility functions that Tor provides by
 looking through `src/lib/*/*.h`.  You can see the
 available containers in `src/lib/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.
 
-We don't use `strcat` or `strcpy` or `sprintf` of any of those notoriously broken
-old C functions.  Use `strlcat`, `strlcpy`, or `tor_snprintf/tor_asprintf` instead.
+
+We don't use `strcat` or `strcpy` or `sprintf` of any of those notoriously
+broken old C functions.  We also avoid `strncat` and `strncpy`. Use
+`strlcat`, `strlcpy`, or `tor_snprintf/tor_asprintf` instead.
 
 We don't call `memcmp()` directly.  Use `fast_memeq()`, `fast_memneq()`,
-`tor_memeq()`, or `tor_memneq()` for most purposes.
+`tor_memeq()`, or `tor_memneq()` for most purposes.  If you really need a
+tristate return value, use `tor_memcmp()` or `fast_memcmp()`.
+
+Don't call `assert()` directly. For hard asserts, use `tor_assert()`. For
+soft asserts, use `tor_assert_nonfatal()` or `BUG()`. If you need to print
+debug information in assert error message, consider using `tor_assertf()` and
+`tor_assertf_nonfatal()`.  If you are writing code that is too low-level to
+use the logging subsystem, use `raw_assert()`.
+
+Don't use `toupper()` and `tolower()` functions. Use `TOR_TOUPPER` and
+`TOR_TOLOWER` macros instead. Similarly, use `TOR_ISALPHA`, `TOR_ISALNUM` et.
+al. instead of `isalpha()`, `isalnum()`, etc.
+
+When allocating new string to be added to a smartlist, use
+`smartlist_add_asprintf()` to do both at once.
+
+Avoid calling BSD socket functions directly. Use portable wrappers to work
+with sockets and socket addresses. Also, sockets should be of type
+`tor_socket_t`.
+
+Don't use any of these functions: they aren't portable. Use the
+version prefixed with `tor_` instead: strtok_r, memmem, memstr,
+asprintf, localtime_r, gmtime_r, inet_aton, inet_ntop, inet_pton,
+getpass, ntohll, htonll.  (This list is incomplete.)
 
-Also see a longer list of functions to avoid in:
-https://people.torproject.org/~nickm/tor-auto/internal/this-not-that.html
 
 What code can use what other code?
 ----------------------------------
@@ -338,8 +370,16 @@ definitions when necessary.)
 Assignment operators shouldn't nest inside other expressions.  (You can
 ignore this inside macro definitions when necessary.)
 
-Functions not to write
-----------------------
+Binary data and wire formats
+----------------------------
+
+Use pointer to `char` when representing NUL-terminated string. To represent
+arbitrary binary data, use pointer to `uint8_t`. (Many older Tor APIs ignore
+this rule.)
+
+Refrain from attempting to encode integers by casting their pointers to byte
+arrays. Use something like `set_uint32()`/`get_uint32()` instead and don't
+forget about endianness.
 
 Try to never hand-write new code to parse or generate binary
 formats. Instead, use trunnel if at all possible.  See
@@ -457,6 +497,9 @@ to use it as a function callback), define it with a name like
       abc_free_(obj);
     }
 
+When deallocating, don't say e.g. `if (x) tor_free(x)`. The convention is to
+have deallocators do nothing when NULL pointer is passed.
+
 Doxygen comment conventions
 ---------------------------