Add `help set` to LLDB Pwndbg (#3068)

* Add `help set` to LLDB

* Change documentation to reflect it

docs/contributing/adding-a-parameter.md

@@ -76,7 +76,7 @@ bn-autosync                        whether to automatically run bn-sync every st
 ```
 Because of the various contexts in which a parameter can be show, the first letter of the `set_show_doc` string should be lowercase (unless the first word is a name or an abbreviation) and there should be no punctuation at the end. This way, Pwndbg and GDB can more easily modify the string to fit it into these contexts.
 ## help_docstring
-While `help_docstring` is not mandatory, it is highly recommended to use it. Put a detailed explanation of what the parameter does here, and explain any caveats. This string does not have a size limit and is shown with the following command in GDB:
+While `help_docstring` is not mandatory, it is highly recommended to use it. Put a detailed explanation of what the parameter does here, and explain any caveats. This string does not have a size limit and is shown with the following command in GDB and LLDB:
 ```text
 pwndbg> help set gdb-workaround-stop-event
 Set asynchronous stop events to improve 'commands' functionality.
@@ -92,8 +92,6 @@ Default: 'disabled'
 Valid values: 'disabled', 'disabled-deadlock', 'enabled'
 ```
 Note that the last two lines are automatically generated by Pwndbg.
-!!! note
-    There is currently no way to display this string nor the `set_show_doc` string in LLDB.
 
 When writing this explanation, it is important to take into account how it will be displayed [in the documentation](https://pwndbg.re/pwndbg/dev/configuration/) after being parsed as markdown. See what `gdb-workaround-stop-event` looks like here: https://pwndbg.re/pwndbg/dev/configuration/config/#gdb-workaround-stop-event . If there wasn't an empty line between `Values explained:` and ``+ `disabled`..`` the list wouldn't have rendered properly.
 ## param_class

pwndbg/commands/config.py

@@ -71,7 +71,9 @@ parser.add_argument(
 )
 
 
-def display_config(filter_pattern: str, scope: Scope, has_file_command: bool = True) -> None:
+def display_config(
+    filter_pattern: str, scope: Scope, has_file_command: bool = True, show_hints: bool = True
+) -> None:
     values = get_config_parameters(scope, filter_pattern)
 
     if not values:
@@ -97,18 +99,19 @@ def display_config(filter_pattern: str, scope: Scope, has_file_command: bool = T
 
         print_row(v.name, value, default, v.set_show_doc, longest_optname, longest_doc)
 
-    print(
-        hint(
-            f"You can set a {scope.name} variable with `set <{scope.name}-var> <value>`, and read more about it with `help set <{scope.name}-var>`."
-        )
-    )
-    if has_file_command:
+    if show_hints:
         print(
             hint(
-                f"You can generate a configuration file using `{scope.name}file` "
-                "- then put it in your .gdbinit after initializing pwndbg."
+                f"You can set a {scope.name} variable with `set <{scope.name}-var> <value>`, and read more about it with `help set <{scope.name}-var>`."
             )
         )
+        if has_file_command:
+            print(
+                hint(
+                    f"You can generate a configuration file using `{scope.name}file` "
+                    "- then put it in your .gdbinit after initializing pwndbg."
+                )
+            )
 
 
 @pwndbg.commands.Command(parser, category=CommandCategory.PWNDBG)

pwndbg/dbg/lldb/pset.py

@@ -1,6 +1,7 @@
 from __future__ import annotations
 
 from typing import Any
+from typing import Optional
 
 import pwndbg
 import pwndbg.color.message as message
@@ -8,16 +9,22 @@ import pwndbg.commands
 import pwndbg.lib.config as cfg
 
 
+def pget(name: str) -> Optional[pwndbg.lib.config.Parameter]:
+    """
+    Retrieves a parameter with a given name.
+    """
+    return pwndbg.config.params.get(name.replace("-", "_"))
+
+
 def pset(name: str, value: str) -> bool:
     """
     Parses and sets a Pwndbg configuration value.
     """
-    name = name.replace("-", "_")
-    if name not in pwndbg.config.params:
+    param = pget(name)
+    if param is None:
         print(message.error(f"Unknown setting '{name}'"))
         return False
 
-    param = pwndbg.config.params[name]
     try:
         new_value = parse_value(param, value)
     except InvalidParse as e:

pwndbg/dbg/lldb/repl/__init__.py

@@ -62,6 +62,7 @@ from pwndbg.color import message
 from pwndbg.dbg import EventType
 from pwndbg.dbg.lldb import LLDB
 from pwndbg.dbg.lldb import OneShotAwaitable
+from pwndbg.dbg.lldb.pset import pget
 from pwndbg.dbg.lldb.pset import pset
 from pwndbg.dbg.lldb.repl.io import IODriver
 from pwndbg.dbg.lldb.repl.io import get_io_driver
@@ -517,6 +518,52 @@ def exec_repl_command(
 
         return True
 
+    if (
+        (bits[0] == "h" or (bits[0].startswith("hel") and "help".startswith(bits[0])))
+        and len(bits) >= 2
+        and bits[1] == "set"
+    ):
+        # This is 'help set'
+        #
+        # We override this command to provide help for the 'set' command
+        # override.
+        warn = False
+        if len(bits) > 3:
+            print("Usage: help set [name]")
+            warn = True
+        elif len(bits) == 2:
+            # In LLDB style, list all valid settings.
+            print("Set a Pwndbg configuration parameter.")
+            print()
+            print("Syntax: set <name> <value>")
+            for scope in pwndbg.lib.config.Scope:
+                print()
+                print(f"Configuration parameters - {scope._name_}:")
+                pwndbg.commands.config.display_config(
+                    "", pwndbg.lib.config.Scope.config, show_hints=False
+                )
+        else:
+            # Show information about a single parameter.
+            param = pget(bits[2])
+            if param is None:
+                warn = True
+            else:
+                print(f"Set {param.set_show_doc}.")
+                print()
+                print(f"Syntax: set {param.name} <value>")
+                print()
+                if param.help_docstring:
+                    print(param.help_docstring)
+
+        if warn:
+            print(
+                message.warn(
+                    "The 'set' command is used exclusively for Pwndbg settings. If you meant to see help for LLDB settings, use the fully spelled-out 'settings' command, instead."
+                )
+            )
+
+        return True
+
     if bits[0] == "ipi":
         # Spawn IPython shell, easy for debugging
         run_ipython_shell()