CFRunLoopServiceMachPort_hooks: Improve disable_mach_msg_errors to …

…generic solution

hilda/snippets/mach/CFRunLoopServiceMachPort_hooks.py

@@ -1,45 +1,44 @@
 import lldb
 
-from hilda.exceptions import SymbolAbsentError
 
-
-def _CFRunLoopServiceMachPort_hook(hilda, *args):
-    """
-    :param hilda.hilda_client.HildaClient hilda:
+def disable_mach_msg_errors() -> None:
     """
-    hilda.jump(hilda.CFRunLoopServiceMachPort_while_ea)
-    hilda.cont()
+    Remove the timeout validation from __CFRunLoopServiceMachPort. This is done by patching the mach_msg_timeout_t
+    parameter (4rd one) to MACH_MSG_TIMEOUT_NONE. On arm the parameter passes on `x3` register.
 
+        __int64 __fastcall __CFRunLoopServiceMachPort(
+            mach_port_name_t a1,
+            mach_msg_header_t **a2,
+            mach_port_t *a3,
+            mach_msg_timeout_t a4,
+            voucher_mach_msg_state_t *a5,
+            id *a6)
 
-def disable_mach_msg_errors() -> None:
-    """
-    Disable the error check inside the CFRunLoopServiceMachPort from the mach_msg syscall.
-    This is used to debug slow handling of mach messages.
+        CoreFoundation:__text:0000000186E5012C ___CFRunLoopServiceMachPort
+        CoreFoundation:__text:0000000186E5012C                 SUB             SP, SP, #0x70
+        CoreFoundation:__text:0000000186E50130                 STP             X28, X27, [SP,#0x60+var_50]
+        CoreFoundation:__text:0000000186E50134                 STP             X26, X25, [SP,#0x60+var_40]
+        CoreFoundation:__text:0000000186E50138                 STP             X24, X23, [SP,#0x60+var_30]
+        CoreFoundation:__text:0000000186E5013C                 STP             X22, X21, [SP,#0x60+var_20]
+        CoreFoundation:__text:0000000186E50140                 STP             X20, X19, [SP,#0x60+var_10]
+        CoreFoundation:__text:0000000186E50144                 STP             X29, X30, [SP,#0x60+var_s0]
+        CoreFoundation:__text:0000000186E50148                 ADD             X29, SP, #0x60
+        CoreFoundation:__text:0000000186E5014C                 MOV             X21, X5
+        CoreFoundation:__text:0000000186E50150                 MOV             X22, X4
+        CoreFoundation:__text:0000000186E50154                 MOV             X23, X3       <-------- Timeout parameter
     """
     hilda = lldb.hilda_client
-    with hilda.stopped():
-        instructions = hilda.symbols.__CFRunLoopServiceMachPort.disass(2000, should_print=False)
-        while_ea = None
-        for instruction in instructions:
-            if (while_ea is None) and instruction.DoesBranch():
-                # Beginning of the `while(true) { ... }`
-                while_ea = instruction.GetOperands(hilda.target)
-                hilda.CFRunLoopServiceMachPort_while_ea = int(hilda.file_symbol(eval(while_ea)))
-            elif instruction.GetMnemonic(hilda.target) in ('brk', 'ud2'):
-                symbol = hilda.symbol(instruction.addr.GetLoadAddress(hilda.target))
-                symbol.bp(
-                    _CFRunLoopServiceMachPort_hook,
-                    forced=True,
-                    name=f'__CFRunLoopServiceMachPort-brk-{int(symbol - hilda.symbols.__CFRunLoopServiceMachPort)}'
-                )
+    if hilda.arch == 'x86_64h':
+        return
 
-        # on iOS 16.x, will need to also patch this one
-        try:
-            handle_error = hilda.symbols['__CFRunLoopServiceMachPort.cold.1']
-        except SymbolAbsentError:
-            return
-
-        for instruction in handle_error.disass(2000, should_print=False):
-            if instruction.GetMnemonic(hilda.target) in ('brk', 'ud2'):
-                # mov x0, x0
-                hilda.symbol(instruction.addr.GetLoadAddress(hilda.target)).poke(b'\xe0\x03\x00\xaa')
+    with hilda.stopped():
+        for inst in hilda.symbols.__CFRunLoopServiceMachPort.disass(200, should_print=False):
+            mnemonic = inst.GetMnemonic(hilda.target)
+            operands = inst.GetOperands(hilda.target)
+            if mnemonic != 'mov' or not operands.endswith('x3'):
+                continue
+            addr = inst.GetAddress()
+            file_addr = addr.GetFileAddress()
+            new_inst = f'{mnemonic} {operands.replace("x3", "0")}'
+            hilda.file_symbol(file_addr).poke_text(new_inst)
+            break