From fb80c8b301e30ec77d1e644a4573822bd22cbdd2 Mon Sep 17 00:00:00 2001
From: Thomas Hebb <tommyhebb@gmail.com>
Date: Fri, 12 Sep 2025 12:12:15 -0400
Subject: [PATCH 1/7] messages_live: New module, initial implementation for
 non-terse messages

---
 src/main.py                  |   9 ++
 src/modules/messages_live.py | 205 +++++++++++++++++++++++++++++++++++
 2 files changed, 214 insertions(+)
 create mode 100644 src/modules/messages_live.py

diff --git a/src/main.py b/src/main.py
index 959b2da..c1029f8 100644
--- a/src/main.py
+++ b/src/main.py
@@ -13,6 +13,7 @@
 from .modules.cli import CommandLineInterface
 from .modules.dlf_dump import DlfDumper
 from .modules.info import InfoRetriever
+from .modules.messages_live import MessagePrinter
 from .modules._utils import FileType
 
 from .inputs.json_geo_read import JsonGeoReader
@@ -72,6 +73,7 @@ def main():
     modules.add_argument('--json-geo-dump', metavar = 'JSON_FILE', type = FileType('a'), help = 'Generate a JSON file containing both raw log frames and GPS coordinates, for further reprocessing. ' +
         'To be used in combination with --adb.')
     modules.add_argument('--decoded-sibs-dump', action = 'store_true', help = 'Print decoded SIBs to stdout (experimental, requires pycrate).')
+    modules.add_argument('--messages-live', action = 'store_true', help = 'Print modem log messages to stdout.')
 
     pcap_options = parser.add_argument_group(title = 'PCAP generation options', description = 'To be used along with --pcap-dump or --wireshark-live.')
 
@@ -84,6 +86,11 @@ def main():
     memory_options.add_argument('--start', metavar = 'MEMORY_START', default = '00000000', help = 'Offset at which to start to dump memory (hex number), by default 00000000.')
     memory_options.add_argument('--stop', metavar = 'MEMORY_STOP', default = 'ffffffff', help = 'Offset at which to stop to dump memory (hex number), by default ffffffff.')
 
+    messages_options = parser.add_argument_group(title = 'Modem log options', description = 'To be used along with --messages-live.')
+
+    messages_options.add_argument('--qdb', metavar = 'QSHRINK_DB', type = FileType('rb'), action = 'append', help = 'Optional QShrink database of terse message strings. If specified multiple times, later files take precedence.')
+    # TODO: subsystem argument?
+
     args = parser.parse_args()
 
     basicConfig(stream = stderr, level = DEBUG if args.verbose else INFO,
@@ -163,6 +170,8 @@ def parse_modules_args(args):
             diag_input.add_module(InfoRetriever(diag_input))
         if args.dlf_dump:
             diag_input.add_module(DlfDumper(diag_input, args.dlf_dump))
+        if args.messages_live:
+            diag_input.add_module(MessagePrinter(diag_input, args.qdb or []))
 
     # if args.efs_dump:
     #     raise NotImplementedError
diff --git a/src/modules/messages_live.py b/src/modules/messages_live.py
new file mode 100644
index 0000000..c97f67b
--- /dev/null
+++ b/src/modules/messages_live.py
@@ -0,0 +1,205 @@
+#!/usr/bin/python3
+#-*- encoding: Utf-8 -*-
+from collections import namedtuple
+from logging import warning
+from struct import Struct, pack # TODO: Clean up?
+
+from ..inputs._base_input import message_id_to_name, MSG_EXT_SUBCMD_SET_ALL_RT_MASKS
+
+from ..protocol.messages import *
+
+class ParseableStruct:
+
+    @classmethod
+    def _parse(cls, data):
+        return cls._make(cls.STRUCT.unpack(data))
+
+    @classmethod
+    def _parse_start(cls, data):
+        parsed = cls._parse(data[:cls.STRUCT.size])
+        remainder = data[cls.STRUCT.size:]
+        return parsed, remainder
+
+
+# From https://github.com/osmocom/osmo-qcdiag/blob/5b01f0bedd70f0c0df589eba347a8580d510d737/src/protocol/protocol.h#L26-L33
+class MsgHeader(ParseableStruct, namedtuple('MsgHeader', ['ts_type', 'num_args', 'drop_cnt', 'timestamp'])):
+    STRUCT = Struct('<BBBQ')
+
+class NormalMeta(ParseableStruct, namedtuple('NormalMeta', ['line', 'ssid', 'ss_mask'])):
+    STRUCT = Struct('<HHI')
+
+
+def args_at_start(data, arg_size, num_args):
+
+    args_size = arg_size * num_args
+
+    if args_size == 0:
+        return [], data
+
+    # TODO: Catch too few bytes
+    args = [data[i:i+arg_size] for i in range(0, args_size, arg_size)]
+    rest = data[args_size:]
+
+    return args, rest
+
+
+"""
+    This module collects, formats, and prints modem debugging logs sourced from
+    diag MSG events.
+"""
+
+class MessagePrinter:
+
+    def __init__(self, diag_input, qshrink_fds):
+
+        self.diag_input = diag_input
+
+
+    def on_init(self):
+
+        self.diag_input.send_recv(DIAG_EXT_MSG_CONFIG_F, pack('<BxxI', MSG_EXT_SUBCMD_SET_ALL_RT_MASKS, 0xffffffff), accept_error = False)
+
+
+    def on_deinit(self):
+
+        self.diag_input.send_recv(DIAG_EXT_MSG_CONFIG_F, pack('<BxxI', MSG_EXT_SUBCMD_SET_ALL_RT_MASKS, 0), accept_error = False)
+
+
+    """
+        Process a single message event, either terse or non-terse.
+    """
+
+    def on_message(self, opcode, payload):
+
+        hdr, data = MsgHeader._parse_start(payload)
+
+        if opcode == DIAG_EXT_MSG_F:
+            meta, rest = NormalMeta._parse_start(data)
+            args, rest = args_at_start(rest, 4, hdr.num_args)
+            string, file, _ = rest.split(b'\x00')
+
+            self.log_message(meta.ssid, meta.ss_mask, meta.line, file, string, args)
+        else:
+            warning(f'Unhandled message opcode {message_id_to_name.get(opcode, opcode)}')
+
+
+    def log_message(self, ssid, ss_mask, line, file, string, args):
+
+        try:
+            formatted = cprintf(string, args).decode('ascii', 'replace')
+        except IndexError:
+            fallback_string = string.decode('ascii', 'replace')
+            fallback_args = ', '.join(f'{int.from_bytes(arg, 'little', signed=False):#010x}' for arg in args)
+
+            formatted = f'{fallback_string} ← [{fallback_args}]'
+
+        # Replace newlines with a glyph so that each message appears on a single line
+        formatted = formatted.replace('\n', '⏎')
+
+        file = file.decode('utf-8', 'replace')
+        line_spec = f'{file}:{line}'
+
+        print(f'[{ssid:5}] {line_spec:44} {formatted}')
+
+
+PRINTF_FLAG = [b'#', b'0', b'-', b' ', b'+']
+PRINTF_LENGTH = [b'hh', b'h', b'll', b'l', b'q', b'L', b'j', b'z', b'Z', b't']
+PRINTF_CONV = [b'd', b'i', b'o', b'u', b'x', b'X', b'e', b'E', b'f', b'F', b'g', b'G', b'a', b'A', b'c', b's', b'p', b'%']
+def cprintf(fmt, args):
+
+    result = bytearray()
+    pos = 0
+
+    def take_int():
+        nonlocal pos
+
+        val = None
+        while pos < len(fmt) and (c := chr(fmt[pos])).isdigit():
+            val = ((val or 0) * 10) + int(c)
+            pos += 1
+        return val
+
+    def take_token(tokens):
+        nonlocal pos
+
+        for t in tokens:
+            if fmt[pos:pos+len(t)] == t:
+                pos += len(t)
+                return t
+        return None
+
+    def take_repeated_tokens(tokens):
+        res = set()
+        while (t := take_token(tokens)) is not None:
+            res.add(t)
+        return res
+
+    # For efficient pop()ing
+    args.reverse()
+
+    while pos < len(fmt):
+        try:
+            conv_start = fmt.index(b'%', pos)
+        except ValueError:
+            result.extend(fmt[pos:])
+            break
+
+        result.extend(fmt[pos:conv_start])
+        pos = conv_start + 1
+
+        flags = take_repeated_tokens(PRINTF_FLAG)
+        width = take_int()
+        if take_token((b'.',)):
+            precision = take_token((b'*',)) or take_int()
+        else:
+            precision = None
+        length = take_token(PRINTF_LENGTH)
+        conv = take_token(PRINTF_CONV)
+
+        if conv is None:
+            # Malformed. Unroll and treat as literal.
+            pos = conv_start + 1
+            result.extend(b'%')
+            continue
+
+        if precision == b'#':
+            precision = int.from_bytes(args.pop(), 'little', signed=True)
+            if precision < 0:
+                precision = None
+
+        # TODO: Trim args based on length?
+
+        signed = False
+        if conv == b'p':
+            flags.add(b'#')
+            conv = b'x'
+        elif conv in (b'd', b'i'):
+            signed = True
+            conv = b'u'
+
+        if conv in (b'u', b'o', b'x', b'X', b'c'):
+            py_flags = b''.join(flags).decode('ascii')
+            py_width = str(width) if width is not None else ''
+            py_precision = f'.{precision}' if precision is not None else ''
+            py_conv = conv.decode('ascii')
+
+            val = int.from_bytes(args.pop(), 'little', signed=signed)
+            formatted = f'%{py_flags}{py_width}{py_precision}{py_conv}' % val
+
+            result.extend(formatted.encode('ascii'))
+        elif conv == b'%':
+            result.extend(b'%')
+        else:
+            # The Qualcomm arg list doesn't really support non-integral types,
+            # so just print the raw conversion specifier and argument value.
+            py_conv = conv.decode('ascii')
+
+            val = int.from_bytes(args.pop(), 'little', signed=False)
+            formatted = f'%{py_conv}[{val:#010x}]'
+
+            result.extend(formatted.encode('ascii'))
+
+    if len(args):
+        raise IndexError('more arguments than format conversions')
+
+    return result

From 6185ef6b8b7e8d5891794d48f54b2c8182440c7a Mon Sep 17 00:00:00 2001
From: Thomas Hebb <tommyhebb@gmail.com>
Date: Fri, 12 Sep 2025 15:26:24 -0400
Subject: [PATCH 2/7] messages_live: Put argument pretty-printing in its own
 function

---
 src/modules/messages_live.py | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/src/modules/messages_live.py b/src/modules/messages_live.py
index c97f67b..02b57ea 100644
--- a/src/modules/messages_live.py
+++ b/src/modules/messages_live.py
@@ -89,9 +89,7 @@ def log_message(self, ssid, ss_mask, line, file, string, args):
             formatted = cprintf(string, args).decode('ascii', 'replace')
         except IndexError:
             fallback_string = string.decode('ascii', 'replace')
-            fallback_args = ', '.join(f'{int.from_bytes(arg, 'little', signed=False):#010x}' for arg in args)
-
-            formatted = f'{fallback_string} ← [{fallback_args}]'
+            formatted = f'{fallback_string} ← {self.debug_args(args)}'
 
         # Replace newlines with a glyph so that each message appears on a single line
         formatted = formatted.replace('\n', '⏎')
@@ -102,6 +100,12 @@ def log_message(self, ssid, ss_mask, line, file, string, args):
         print(f'[{ssid:5}] {line_spec:44} {formatted}')
 
 
+    @staticmethod
+    def debug_args(args):
+        values = ', '.join(f'{int.from_bytes(arg, 'little', signed=False):#010x}' for arg in args)
+        return f'[{values}]'
+
+
 PRINTF_FLAG = [b'#', b'0', b'-', b' ', b'+']
 PRINTF_LENGTH = [b'hh', b'h', b'll', b'l', b'q', b'L', b'j', b'z', b'Z', b't']
 PRINTF_CONV = [b'd', b'i', b'o', b'u', b'x', b'X', b'e', b'E', b'f', b'F', b'g', b'G', b'a', b'A', b'c', b's', b'p', b'%']

From ea59f6a67c66d8b31abdfe3c58feab4be96c03f8 Mon Sep 17 00:00:00 2001
From: Thomas Hebb <tommyhebb@gmail.com>
Date: Fri, 12 Sep 2025 16:01:44 -0400
Subject: [PATCH 3/7] messages_live: Warn of dropped messages

---
 src/modules/messages_live.py | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/modules/messages_live.py b/src/modules/messages_live.py
index 02b57ea..fff8ddf 100644
--- a/src/modules/messages_live.py
+++ b/src/modules/messages_live.py
@@ -73,6 +73,9 @@ def on_message(self, opcode, payload):
 
         hdr, data = MsgHeader._parse_start(payload)
 
+        if hdr.drop_cnt > 0:
+            warning(f"Dropped {hdr.drop_cnt} log message(s); consider adding filters")
+
         if opcode == DIAG_EXT_MSG_F:
             meta, rest = NormalMeta._parse_start(data)
             args, rest = args_at_start(rest, 4, hdr.num_args)

From e090823333f471746222e08dbd24d1039cf3e14c Mon Sep 17 00:00:00 2001
From: Thomas Hebb <tommyhebb@gmail.com>
Date: Fri, 12 Sep 2025 15:27:19 -0400
Subject: [PATCH 4/7] messages_live: Support terse messages

---
 src/modules/messages_live.py | 152 ++++++++++++++++++++++++++++++++++-
 1 file changed, 151 insertions(+), 1 deletion(-)

diff --git a/src/modules/messages_live.py b/src/modules/messages_live.py
index fff8ddf..3ba12a9 100644
--- a/src/modules/messages_live.py
+++ b/src/modules/messages_live.py
@@ -1,8 +1,12 @@
 #!/usr/bin/python3
 #-*- encoding: Utf-8 -*-
 from collections import namedtuple
-from logging import warning
+import io
+from logging import warning, debug
+import re
 from struct import Struct, pack # TODO: Clean up?
+import uuid
+import zlib
 
 from ..inputs._base_input import message_id_to_name, MSG_EXT_SUBCMD_SET_ALL_RT_MASKS
 
@@ -28,6 +32,12 @@ class MsgHeader(ParseableStruct, namedtuple('MsgHeader', ['ts_type', 'num_args',
 class NormalMeta(ParseableStruct, namedtuple('NormalMeta', ['line', 'ssid', 'ss_mask'])):
     STRUCT = Struct('<HHI')
 
+class TerseMeta(ParseableStruct, namedtuple('TerseMeta', ['line', 'ssid', 'ss_mask', 'hash'])):
+    STRUCT = Struct('<HHII')
+
+class Qsr4TerseMeta(ParseableStruct, namedtuple('Qsr4TerseMeta', ['hash', 'magic'])):
+    STRUCT = Struct('<IH')
+
 
 def args_at_start(data, arg_size, num_args):
 
@@ -54,6 +64,10 @@ def __init__(self, diag_input, qshrink_fds):
 
         self.diag_input = diag_input
 
+        self.qdb = QdbFile()
+        for fd in qshrink_fds:
+            self.qdb.parse(fd)
+
 
     def on_init(self):
 
@@ -82,6 +96,27 @@ def on_message(self, opcode, payload):
             string, file, _ = rest.split(b'\x00')
 
             self.log_message(meta.ssid, meta.ss_mask, meta.line, file, string, args)
+        elif opcode == DIAG_QSR_EXT_MSG_TERSE_F:
+            meta, rest = TerseMeta._parse_start(data)
+            args, rest = args_at_start(rest, 4, hdr.num_args)
+
+            h = self.qdb.messages.get(meta.hash)
+            if h is not None:
+                self.log_message(meta.ssid, meta.ss_mask, meta.line, h.file, h.string, args)
+            else:
+                warning(f'Unmapped terse message (try --qdb): {meta.hash}{self.debug_args(args)}')
+        elif opcode == DIAG_QSR4_EXT_MSG_TERSE_F:
+            meta, rest = Qsr4TerseMeta._parse_start(data)
+
+            arg_size = (hdr.num_args >> 4) & 0xf
+            num_args = (hdr.num_args >> 0) & 0xf
+            args, _ = args_at_start(rest, arg_size, num_args)
+
+            h = self.qdb.qsr4_messages.get(meta.hash)
+            if h is not None:
+                self.log_message(h.ssid, h.ss_mask, h.line, h.file, h.string, args)
+            else:
+                warning(f'Unmapped terse message (try --qdb): {meta.hash}{self.debug_args(args)}')
         else:
             warning(f'Unhandled message opcode {message_id_to_name.get(opcode, opcode)}')
 
@@ -109,6 +144,89 @@ def debug_args(args):
         return f'[{values}]'
 
 
+class QdbFile:
+
+    HashedMessage = namedtuple('HashedMessage', ['hash', 'file', 'string'])
+    Qsr4HashedMessage = namedtuple('Qsr4HashedMessage', ['hash', 'ss_mask', 'ssid', 'line', 'file', 'string'])
+
+    QDB_HEADER_SIZE = 0x40
+    TAG_REGEX = re.compile(rb'<(\w+)>(?:\s*(.*?)\s*<[\\/]\1>)?\s*')
+
+
+    def __init__(self):
+
+        self.messages = {}
+        self.qsr4_messages = {}
+
+
+    def parse(self, file):
+
+        qdb_header = file.read(self.QDB_HEADER_SIZE)
+        if len(qdb_header) == self.QDB_HEADER_SIZE and qdb_header.startswith(b'\x7fQDB'):
+            # Compressed `.qdb` file
+            guid = uuid.UUID(bytes=qdb_header[4:20])
+            debug(f'Detected compressed .qdb file with GUID {guid}')
+
+            inner = io.BufferedReader(ZlibReader(file))
+            parsed = self.parse_uncompressed(inner)
+
+            # TODO: check GUID match
+        else:
+            # Not compressed, try to parse directly
+            file.seek(0)
+            parsed = self.parse_uncompressed(file)
+
+        debug(f'Parsed QDB {parsed}')
+        return parsed
+
+
+    def parse_uncompressed(self, file):
+
+        meta = {}
+
+        cur_tag = None
+        expected_close = None
+        for line in file:
+            line = line.rstrip(b'\n')
+            if not line or line.startswith(b'#'):
+                continue
+            elif cur_tag is not None and line.rstrip() in expected_close:
+                cur_tag = None
+                expected_close = None
+            elif cur_tag is None and (match := self.TAG_REGEX.fullmatch(line)):
+                tag, singleline_content = match.groups()
+                if singleline_content is not None:
+                    # Single-line tags contain file metadata
+                    meta[tag] = singleline_content
+                else:
+                    cur_tag = tag
+                    expected_close = [rb'<\%s>' % cur_tag, rb'</%s>' % cur_tag]
+            else:
+                self.process_line(cur_tag, line)
+
+        if cur_tag is not None:
+            raise ValueError('unclosed tag', cur_tag)
+
+        return meta
+
+
+    def process_line(self, tag, line):
+
+        if tag is None:
+            m = self.intify(self.HashedMessage, line.split(b':', 2), ('hash',))
+            self.messages[m.hash] = m
+        elif tag == b'Content':
+            m = self.intify(self.Qsr4HashedMessage, line.split(b':', 5), ('hash', 'ss_mask', 'ssid', 'line'))
+            self.qsr4_messages[m.hash] = m
+
+
+    @staticmethod
+    def intify(tuple_type, tuple_values, to_convert):
+
+        mapped = (int(v) if tuple_type._fields[i] in to_convert else v for i, v in enumerate(tuple_values))
+        return tuple_type._make(mapped)
+
+
 PRINTF_FLAG = [b'#', b'0', b'-', b' ', b'+']
 PRINTF_LENGTH = [b'hh', b'h', b'll', b'l', b'q', b'L', b'j', b'z', b'Z', b't']
 PRINTF_CONV = [b'd', b'i', b'o', b'u', b'x', b'X', b'e', b'E', b'f', b'F', b'g', b'G', b'a', b'A', b'c', b's', b'p', b'%']
@@ -210,3 +328,35 @@ def take_repeated_tokens(tokens):
         raise IndexError('more arguments than format conversions')
 
     return result
+
+
+class ZlibReader(io.RawIOBase):
+
+    def __init__(self, raw):
+
+        self.raw = raw
+        self.decompressor = zlib.decompressobj()
+
+
+    def readable(self):
+
+        return True
+
+
+    def readinto(self, buf):
+
+        if not len(buf):
+            return 0
+
+        compressed = self.decompressor.unconsumed_tail or self.raw.read(io.DEFAULT_BUFFER_SIZE)
+        decompressed = self.decompressor.decompress(compressed, len(buf))
+
+        buf[:len(decompressed)] = decompressed
+        return len(decompressed)
+
+
+    def close(self):
+
+        self.decompressor = None
+        self.raw.close()
+        return super().close()

From beb12a4d288a62458def22ecc97a8c25296a9d32 Mon Sep 17 00:00:00 2001
From: Thomas Hebb <tommyhebb@gmail.com>
Date: Sat, 13 Sep 2025 12:28:44 -0400
Subject: [PATCH 5/7] messages_live: Print substituted argument values in bold

---
 src/main.py                  |  3 ++-
 src/modules/messages_live.py | 23 +++++++++++++++++------
 2 files changed, 19 insertions(+), 7 deletions(-)

diff --git a/src/main.py b/src/main.py
index c1029f8..510c626 100644
--- a/src/main.py
+++ b/src/main.py
@@ -89,6 +89,7 @@ def main():
     messages_options = parser.add_argument_group(title = 'Modem log options', description = 'To be used along with --messages-live.')
 
     messages_options.add_argument('--qdb', metavar = 'QSHRINK_DB', type = FileType('rb'), action = 'append', help = 'Optional QShrink database of terse message strings. If specified multiple times, later files take precedence.')
+    messages_options.add_argument('--no-style', action = 'store_true', help = "Don't highlight argument values in bold even when a TTY is present.")
     # TODO: subsystem argument?
 
     args = parser.parse_args()
@@ -171,7 +172,7 @@ def parse_modules_args(args):
         if args.dlf_dump:
             diag_input.add_module(DlfDumper(diag_input, args.dlf_dump))
         if args.messages_live:
-            diag_input.add_module(MessagePrinter(diag_input, args.qdb or []))
+            diag_input.add_module(MessagePrinter(diag_input, args.qdb or [], not args.no_style))
 
     # if args.efs_dump:
     #     raise NotImplementedError
diff --git a/src/modules/messages_live.py b/src/modules/messages_live.py
index 3ba12a9..f71706c 100644
--- a/src/modules/messages_live.py
+++ b/src/modules/messages_live.py
@@ -5,6 +5,7 @@
 from logging import warning, debug
 import re
 from struct import Struct, pack # TODO: Clean up?
+import sys
 import uuid
 import zlib
 
@@ -60,10 +61,12 @@ def args_at_start(data, arg_size, num_args):
 
 class MessagePrinter:
 
-    def __init__(self, diag_input, qshrink_fds):
+    def __init__(self, diag_input, qshrink_fds, enable_style):
 
         self.diag_input = diag_input
 
+        self.enable_style = enable_style and sys.stdout.isatty()
+
         self.qdb = QdbFile()
         for fd in qshrink_fds:
             self.qdb.parse(fd)
@@ -124,10 +127,10 @@ def on_message(self, opcode, payload):
     def log_message(self, ssid, ss_mask, line, file, string, args):
 
         try:
-            formatted = cprintf(string, args).decode('ascii', 'replace')
+            formatted = cprintf(string, args, self.bold).decode('ascii', 'replace')
         except IndexError:
             fallback_string = string.decode('ascii', 'replace')
-            formatted = f'{fallback_string} ← {self.debug_args(args)}'
+            formatted = f'{fallback_string} ← {self.bold(self.debug_args(args))}'
 
         # Replace newlines with a glyph so that each message appears on a single line
         formatted = formatted.replace('\n', '⏎')
@@ -138,6 +141,14 @@ def log_message(self, ssid, ss_mask, line, file, string, args):
         print(f'[{ssid:5}] {line_spec:44} {formatted}')
 
 
+    def bold(self, text):
+
+        if self.enable_style:
+            return f'\x1b[1m{text}\x1b[0m'
+        else:
+            return text
+
+
     @staticmethod
     def debug_args(args):
         values = ', '.join(f'{int.from_bytes(arg, 'little', signed=False):#010x}' for arg in args)
@@ -230,7 +241,7 @@ def intify(tuple_type, tuple_values, to_convert):
 PRINTF_FLAG = [b'#', b'0', b'-', b' ', b'+']
 PRINTF_LENGTH = [b'hh', b'h', b'll', b'l', b'q', b'L', b'j', b'z', b'Z', b't']
 PRINTF_CONV = [b'd', b'i', b'o', b'u', b'x', b'X', b'e', b'E', b'f', b'F', b'g', b'G', b'a', b'A', b'c', b's', b'p', b'%']
-def cprintf(fmt, args):
+def cprintf(fmt, args, arg_styler=lambda x: x):
 
     result = bytearray()
     pos = 0
@@ -309,7 +320,7 @@ def take_repeated_tokens(tokens):
             py_conv = conv.decode('ascii')
 
             val = int.from_bytes(args.pop(), 'little', signed=signed)
-            formatted = f'%{py_flags}{py_width}{py_precision}{py_conv}' % val
+            formatted = arg_styler(f'%{py_flags}{py_width}{py_precision}{py_conv}' % val)
 
             result.extend(formatted.encode('ascii'))
         elif conv == b'%':
@@ -320,7 +331,7 @@ def take_repeated_tokens(tokens):
             py_conv = conv.decode('ascii')
 
             val = int.from_bytes(args.pop(), 'little', signed=False)
-            formatted = f'%{py_conv}[{val:#010x}]'
+            formatted = arg_styler(f'%{py_conv}[{val:#010x}]')
 
             result.extend(formatted.encode('ascii'))
 

From 0a5aedec9ec997b1b73fd2b57a6eeb5f10549748 Mon Sep 17 00:00:00 2001
From: Thomas Hebb <tommyhebb@gmail.com>
Date: Sat, 13 Sep 2025 12:36:13 -0400
Subject: [PATCH 6/7] messages_live: Allow filtering to specific subsystems

This doesn't currently allow sending a range of subsystem IDs, nor do we
print the mask of each log message, making the mask piece of the
argument difficult to determine. But it's a good start.
---
 src/inputs/_base_input.py    |  1 +
 src/main.py                  | 14 ++++++++++++--
 src/modules/messages_live.py | 11 ++++++++---
 3 files changed, 21 insertions(+), 5 deletions(-)

diff --git a/src/inputs/_base_input.py b/src/inputs/_base_input.py
index 51a67c0..a89ace6 100644
--- a/src/inputs/_base_input.py
+++ b/src/inputs/_base_input.py
@@ -15,6 +15,7 @@
 
 LOG_CONFIG_DISABLE_OP = 0
 
+MSG_EXT_SUBCMD_SET_RT_MASK = 4
 MSG_EXT_SUBCMD_SET_ALL_RT_MASKS = 5
 MSG_LVL_NONE = 0
 
diff --git a/src/main.py b/src/main.py
index 510c626..ebaef2c 100644
--- a/src/main.py
+++ b/src/main.py
@@ -88,9 +88,19 @@ def main():
 
     messages_options = parser.add_argument_group(title = 'Modem log options', description = 'To be used along with --messages-live.')
 
+    def msg_filter(string):
+        parts = [int(x, 0) for x in string.split(':')]
+        if len(parts) == 1:
+            # Enable all mask bits
+            return [parts[0], 0xffffffff]
+        elif len(parts) == 2:
+            return parts
+        else:
+            raise ValueError('message filter must be in the format SUBSYS[:MASK]')
+
     messages_options.add_argument('--qdb', metavar = 'QSHRINK_DB', type = FileType('rb'), action = 'append', help = 'Optional QShrink database of terse message strings. If specified multiple times, later files take precedence.')
     messages_options.add_argument('--no-style', action = 'store_true', help = "Don't highlight argument values in bold even when a TTY is present.")
-    # TODO: subsystem argument?
+    messages_options.add_argument('--msg-filter', metavar = 'SUBSYS[:MASK]', type = msg_filter, action = 'append', help = 'Enable messages for the given subsystem. Specify multiple times, or omit to show all messages.')
 
     args = parser.parse_args()
 
@@ -172,7 +182,7 @@ def parse_modules_args(args):
         if args.dlf_dump:
             diag_input.add_module(DlfDumper(diag_input, args.dlf_dump))
         if args.messages_live:
-            diag_input.add_module(MessagePrinter(diag_input, args.qdb or [], not args.no_style))
+            diag_input.add_module(MessagePrinter(diag_input, args.qdb or [], args.msg_filter, not args.no_style))
 
     # if args.efs_dump:
     #     raise NotImplementedError
diff --git a/src/modules/messages_live.py b/src/modules/messages_live.py
index f71706c..6c165bd 100644
--- a/src/modules/messages_live.py
+++ b/src/modules/messages_live.py
@@ -9,7 +9,7 @@
 import uuid
 import zlib
 
-from ..inputs._base_input import message_id_to_name, MSG_EXT_SUBCMD_SET_ALL_RT_MASKS
+from ..inputs._base_input import message_id_to_name, MSG_EXT_SUBCMD_SET_RT_MASK, MSG_EXT_SUBCMD_SET_ALL_RT_MASKS
 
 from ..protocol.messages import *
 
@@ -61,10 +61,11 @@ def args_at_start(data, arg_size, num_args):
 
 class MessagePrinter:
 
-    def __init__(self, diag_input, qshrink_fds, enable_style):
+    def __init__(self, diag_input, qshrink_fds, msg_filters, enable_style):
 
         self.diag_input = diag_input
 
+        self.msg_filters = msg_filters
         self.enable_style = enable_style and sys.stdout.isatty()
 
         self.qdb = QdbFile()
@@ -74,7 +75,11 @@ def __init__(self, diag_input, qshrink_fds, enable_style):
 
     def on_init(self):
 
-        self.diag_input.send_recv(DIAG_EXT_MSG_CONFIG_F, pack('<BxxI', MSG_EXT_SUBCMD_SET_ALL_RT_MASKS, 0xffffffff), accept_error = False)
+        if self.msg_filters is None:
+            self.diag_input.send_recv(DIAG_EXT_MSG_CONFIG_F, pack('<BxxI', MSG_EXT_SUBCMD_SET_ALL_RT_MASKS, 0xffffffff), accept_error = False)
+        else:
+            for f in self.msg_filters:
+                self.diag_input.send_recv(DIAG_EXT_MSG_CONFIG_F, pack('<BHHxxI', MSG_EXT_SUBCMD_SET_RT_MASK, f[0], f[0], f[1]), accept_error = False)
 
 
     def on_deinit(self):

From a447d929116b9b8618065fec911b3a6d39b41e5d Mon Sep 17 00:00:00 2001
From: Thomas Hebb <tommyhebb@gmail.com>
Date: Sat, 13 Sep 2025 13:44:07 -0400
Subject: [PATCH 7/7] messages_live: Stylistic cleanups

---
 src/modules/messages_live.py | 31 +++++++++++++++----------------
 1 file changed, 15 insertions(+), 16 deletions(-)

diff --git a/src/modules/messages_live.py b/src/modules/messages_live.py
index 6c165bd..dac359a 100644
--- a/src/modules/messages_live.py
+++ b/src/modules/messages_live.py
@@ -40,20 +40,6 @@ class Qsr4TerseMeta(ParseableStruct, namedtuple('Qsr4TerseMeta', ['hash', 'magic
     STRUCT = Struct('<IH')
 
 
-def args_at_start(data, arg_size, num_args):
-
-    args_size = arg_size * num_args
-
-    if args_size == 0:
-        return [], data
-
-    # TODO: Catch too few bytes
-    args = [data[i:i+arg_size] for i in range(0, args_size, arg_size)]
-    rest = data[args_size:]
-
-    return args, rest
-
-
 """
     This module collects, formats, and prints modem debugging logs sourced from
     diag MSG events.
@@ -156,6 +142,7 @@ def bold(self, text):
 
     @staticmethod
     def debug_args(args):
+
         values = ', '.join(f'{int.from_bytes(arg, 'little', signed=False):#010x}' for arg in args)
         return f'[{values}]'
 
@@ -253,7 +240,6 @@ def cprintf(fmt, args, arg_styler=lambda x: x):
 
     def take_int():
         nonlocal pos
-
         val = None
         while pos < len(fmt) and (c := chr(fmt[pos])).isdigit():
             val = ((val or 0) * 10) + int(c)
@@ -262,7 +248,6 @@ def take_int():
 
     def take_token(tokens):
         nonlocal pos
-
         for t in tokens:
             if fmt[pos:pos+len(t)] == t:
                 pos += len(t)
@@ -346,6 +331,20 @@ def take_repeated_tokens(tokens):
     return result
 
 
+def args_at_start(data, arg_size, num_args):
+
+    args_size = arg_size * num_args
+
+    if args_size == 0:
+        return [], data
+
+    # TODO: Catch too few bytes
+    args = [data[i:i+arg_size] for i in range(0, args_size, arg_size)]
+    rest = data[args_size:]
+
+    return args, rest
+
+
 class ZlibReader(io.RawIOBase):
 
     def __init__(self, raw):