[Updated] Add process_info/1 and process_info/2 with list argument

CHANGELOG.md

@@ -32,10 +32,15 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Added USB CDC port drivers for ESP32, RP2, and STM32 platforms
 - Added a Linux `gpio` driver for the generic_unix port (in `avm_unix`) using sysfs
 - Added `console:print_err/1` to write to standard error
+- Added support for `process_info/1` and `process_info/2` with list argument
 - Added `erlang:term_to_binary/2`, `erlang:is_builtin/3` and `erlang:bitstring_to_list/1`
 - Added `lists:mapfoldr/3`
 
 ### Changed
+- `erlang:process_info/2` now accepts only pids of local processes, as Erlang/OTP does:
+  calling it with a port now raises `badarg` (previous versions accepted any id-carrying
+  term, so it could be used to read port information; there is no `erlang:port_info/2`
+  in AtomVM yet to migrate such code to)
 - Updated network type db() to dbm() to reflect the actual representation of the type
 - Use ES6 modules for emscripten port, using .mjs suffix
 - `ahttp_client` now returns `{error, {parser, incomplete_response}}` when a socket closes mid-response
@@ -77,6 +82,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Fixed `ahttp_client` crash on headers with empty or all-whitespace values
 - Fixed a bug in `supervisor` handling of failing child
 - Fixed two bugs related to closing fds in `atomvm:subprocess/4`
+- Fixed `message_queue_len` (as reported by `erlang:process_info/2`): unprocessed signals,
+  such as monitor or unlink requests, were counted as queued messages
+- Fixed a process hanging forever after catching an exception raised asynchronously by a
+  trapping BIF: the trap flag was left set, so the process parked at the next scheduling
+  point and never ran again
 - Fixed `erlang:localtime/1` memory leak, use-after-free, and TZ restore bugs on newlib/picolibc
 - Fixed ESP32 I2C driver resource leaks, half-closed state, and close-during-transmission errors
 - Fixed several underallocation issues that could trigger data corruption on `binary:replace`, `zlib:compress` and bsd socket recv code.

UPDATING.md

@@ -19,6 +19,10 @@ bitshifts: e.g. `(16#FFFF band 0xF) bsl 252`.
 - `binary_to_integer` and `list_to_integer` do not raise `overflow` error anymore, they instead
 raise `badarg` when trying to parse an integer that exceeds 256 bits. Update any relevant error
 handling code.
+- `erlang:process_info/2` now accepts only pids of local processes, as Erlang/OTP does: calling
+it with a port raises `badarg`. Previous versions accepted any id-carrying term, so it could be
+used to read port information; there is no `erlang:port_info/2` in AtomVM yet, so such calls
+must be removed or guarded when updating.
 - ESP32 builds with Elixir support may be configured without making changes to git-tracked files
 using `idf.py -DATOMVM_ELIXIR_SUPPORT=on set-target ${CHIP}` instead of copying
 partitions-elixir.csv to partitions.csv. This configures the build to use partitions-elixir.csv for

doc/src/apidocs/libatomvm/data_structures.rst

@@ -15,18 +15,12 @@ Data Structures
    :maxdepth: 4
    :caption: Structs
 
-.. doxygenstruct:: AtomsHashTable
-   :allow-dot-graphs:
 .. doxygenstruct:: AtomStringIntPair
    :allow-dot-graphs:
 .. doxygenstruct:: AtomTable
    :allow-dot-graphs:
 .. doxygenstruct:: AVMPackData
    :allow-dot-graphs:
-.. doxygenstruct:: BuiltInAtomRequestSignal
-   :allow-dot-graphs:
-.. doxygenstruct:: BuiltInAtomSignal
-   :allow-dot-graphs:
 .. doxygenstruct:: CharDataToBytesAcc
    :allow-dot-graphs:
 .. doxygenstruct:: CharDataToBytesSizeAcc
@@ -68,6 +62,8 @@ Data Structures
    :allow-dot-graphs:
 .. doxygenstruct:: IFFRecord
    :allow-dot-graphs:
+.. doxygenstruct:: ImmediateSignal
+   :allow-dot-graphs:
 .. doxygenstruct:: InMemoryAVMPack
    :allow-dot-graphs:
 .. defined in excluded opcodesswitch.h
@@ -116,6 +112,8 @@ Data Structures
 .. doxygenstruct:: Nif
    :allow-dot-graphs:
 .. doxygenstruct:: PrinterFun
+.. doxygenstruct:: ProcessInfoRequestSignal
+   :allow-dot-graphs:
 .. doxygenstruct:: RefcBinary
    :allow-dot-graphs:
 .. doxygenstruct:: RefcBinaryAVMPack

doc/src/programmers-guide.md

@@ -576,22 +576,27 @@ You can obtain a list of all processes in the system via [`erlang:processes/0`](
 Pids = erlang:processes().
 ```
 
-And for each process, you can get detailed process information via the [`erlang:process_info/2`](./apidocs/erlang/estdlib/erlang.md#process_info2) function:
+And for each process, you can get detailed process information via the [`erlang:process_info/1`](./apidocs/erlang/estdlib/erlang.md#process_info1) and [`erlang:process_info/2`](./apidocs/erlang/estdlib/erlang.md#process_info2) functions:
 
 ```erlang
 io:format("Heap size for Pid ~p: ~p~n", [Pid, erlang:process_info(Pid, heap_size)]).
 ```
 
-The return value is a tuple containing the key passed into the `erlang:process_info/2` function and its associated value.
+The return value is a tuple containing the key passed into the `erlang:process_info/2` function and its associated value, e.g. `{heap_size, 170}`. A list of keys may be passed instead of a single key, in which case the result is a list with one `{Key, Value}` tuple per requested key, in request order. `erlang:process_info/1` returns the default key set in one call. As in Erlang/OTP, these functions return `undefined` if the process is not alive, and querying the single key `registered_name` on a process without a registered name returns `[]`.
 
 The currently supported keys are enumerated in the following table:
 
 | Key | Value Type | Description |
 |-----|------------|-------------|
 | `heap_size` | `non_neg_integer()` | Number of terms (in machine words) used in the process heap |
+| `total_heap_size` | `non_neg_integer()` | Number of terms (in machine words) used in the process heap, including heap fragments |
 | `stack_size` | `non_neg_integer()` | Number of terms (in machine words) used in the process stack |
 | `message_queue_len` | `non_neg_integer()` | Number of unprocessed messages in the process mailbox |
 | `memory` | `non_neg_integer()` | Total number of bytes used by the process (estimate) |
+| `registered_name` | `atom()` | The registered name of the process |
+| `links` | `[pid()]` | The processes and ports the process is linked to |
+| `monitored_by` | `[pid() \| port() \| resource()]` | The processes, ports and NIF resources monitoring the process |
+| `trap_exit` | `boolean()` | Whether the process is trapping exits |
 
 See the `word_size` key in the [System APIs](#system-apis) section for information about how to find the number of bytes used in a machine word on the current platform.
 

libs/estdlib/src/erlang.erl

@@ -31,6 +31,7 @@
     start_timer/3, start_timer/4,
     cancel_timer/1,
     send_after/3,
+    process_info/1,
     process_info/2,
     system_info/1,
     system_flag/2,
@@ -319,6 +320,39 @@ cancel_timer(TimerRef) ->
 send_after(Time, Dest, Msg) ->
     timer_manager:send_after(Time, Dest, Msg).
 
+%%-----------------------------------------------------------------------------
+%% @param   Pid the process pid.
+%% @returns a list of `{Key, Value}' tuples, or `undefined' if the process
+%%          is not alive.
+%% @doc     Return information about the specified process.
+%%
+%% As in Erlang/OTP, the result covers a default set of keys; AtomVM returns
+%% the supported subset of OTP's default set, in the same relative order:
+%% `registered_name' (omitted when the process is not registered, first
+%% otherwise), `message_queue_len', `links', `trap_exit', `total_heap_size',
+%% `heap_size' and `stack_size'.
+%% @end
+%%-----------------------------------------------------------------------------
+-spec process_info(Pid :: pid()) -> [{atom(), term()}] | undefined.
+process_info(Pid) when erlang:is_pid(Pid) ->
+    case
+        erlang:process_info(Pid, [
+            registered_name,
+            message_queue_len,
+            links,
+            trap_exit,
+            total_heap_size,
+            heap_size,
+            stack_size
+        ])
+    of
+        undefined -> undefined;
+        [{registered_name, []} | Info] -> Info;
+        Info -> Info
+    end;
+process_info(Pid) ->
+    erlang:error(badarg, [Pid]).
+
 %%-----------------------------------------------------------------------------
 %% @param   Pid the process pid.
 %% @param   Key key used to find process information.
@@ -338,20 +372,26 @@ send_after(Time, Dest, Msg) ->
 %%      <li><b>memory</b> the estimated total number of bytes in use by the process (integer)</li>
 %%      <li><b>links</b> the list of linked processes</li>
 %%      <li><b>monitored_by</b> the list of processes, NIF resources or ports that monitor the process</li>
+%%      <li><b>trap_exit</b> whether the process is trapping exits (boolean)</li>
 %% </ul>
-%% Specifying an unsupported term or atom raises a bad_arg error.
+%% A list of keys may also be specified, in which case the result is a list
+%% with one `{Key, Value}' tuple per requested key, in the same order and
+%% with duplicates preserved, or `undefined' if the process is not alive.
+%% Specifying an unsupported term or atom raises a badarg error.
 %%
 %% @end
 %%-----------------------------------------------------------------------------
 -spec process_info
-    (Pid :: pid(), heap_size) -> {heap_size, non_neg_integer()};
-    (Pid :: pid(), total_heap_size) -> {total_heap_size, non_neg_integer()};
-    (Pid :: pid(), registered_name) -> {registered_name, term()} | [];
-    (Pid :: pid(), stack_size) -> {stack_size, non_neg_integer()};
-    (Pid :: pid(), message_queue_len) -> {message_queue_len, non_neg_integer()};
-    (Pid :: pid(), memory) -> {memory, non_neg_integer()};
-    (Pid :: pid(), links) -> {links, [pid()]};
-    (Pid :: pid(), monitored_by) -> {monitored_by, [pid() | resource() | port()]}.
+    (Pid :: pid(), heap_size) -> {heap_size, non_neg_integer()} | undefined;
+    (Pid :: pid(), total_heap_size) -> {total_heap_size, non_neg_integer()} | undefined;
+    (Pid :: pid(), registered_name) -> {registered_name, term()} | [] | undefined;
+    (Pid :: pid(), stack_size) -> {stack_size, non_neg_integer()} | undefined;
+    (Pid :: pid(), message_queue_len) -> {message_queue_len, non_neg_integer()} | undefined;
+    (Pid :: pid(), memory) -> {memory, non_neg_integer()} | undefined;
+    (Pid :: pid(), links) -> {links, [pid()]} | undefined;
+    (Pid :: pid(), monitored_by) -> {monitored_by, [pid() | resource() | port()]} | undefined;
+    (Pid :: pid(), trap_exit) -> {trap_exit, boolean()} | undefined;
+    (Pid :: pid(), [atom()]) -> [{atom(), term()}] | undefined.
 process_info(_Pid, _Key) ->
     erlang:nif_error(undefined).