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Support ZM 1.38.0 SharedData struct format and fix decode errors #58

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156 changes: 101 additions & 55 deletions pyzm/ZMMemory.py
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Original file line number Diff line number Diff line change
Expand Up @@ -2,6 +2,9 @@
ZMMemory
=====================
Wrapper to access SHM for Monitor status

Supports both ZoneMinder 1.36.x and 1.38.0+ SharedData struct formats.
The version is auto-detected from the 'size' field in shared memory.
"""


Expand All @@ -13,51 +16,45 @@
import pyzm.helpers.globals as g


"""
shared_data => { type=>'SharedData', seq=>$mem_seq++, contents=> {
size => { type=>'uint32', seq=>$mem_seq++ }, I
last_write_index => { type=>'uint32', seq=>$mem_seq++ }, i
last_read_index => { type=>'uint32', seq=>$mem_seq++ }, i
state => { type=>'uint32', seq=>$mem_seq++ }, I
capture_fps => { type=>'double', seq=>$mem_seq++ }, d
analysis_fps => { type=>'double', seq=>$mem_seq++ }, d
last_event => { type=>'uint64', seq=>$mem_seq++ }, Q
action => { type=>'uint32', seq=>$mem_seq++ }, I
brightness => { type=>'int32', seq=>$mem_seq++ }, i
hue => { type=>'int32', seq=>$mem_seq++ }, i
colour => { type=>'int32', seq=>$mem_seq++ }, i
contrast => { type=>'int32', seq=>$mem_seq++ }, i
alarm_x => { type=>'int32', seq=>$mem_seq++ }, i
alarm_y => { type=>'int32', seq=>$mem_seq++ }, i
valid => { type=>'uint8', seq=>$mem_seq++ }, ?
active => { type=>'uint8', seq=>$mem_seq++ }, ?
signal => { type=>'uint8', seq=>$mem_seq++ }, ?
format => { type=>'uint8', seq=>$mem_seq++ }, ?
imagesize => { type=>'uint32', seq=>$mem_seq++ }, I
last_frame_score => { type=>'uint32', seq=>$mem_seq++ }, I
audio_frequency => { type=>'uint32', seq=>$mem_seq++ }, I
audio_channels => { type=>'uint32', seq=>$mem_seq++ }, I
startup_time => { type=>'time_t64', seq=>$mem_seq++ }, q
zmc_heartbeat_time => { type=>'time_t64', seq=>$mem_seq++ }, q
last_write_time => { type=>'time_t64', seq=>$mem_seq++ }, q
last_read_time => { type=>'time_t64', seq=>$mem_seq++ }, q
control_state => { type=>'uint8[256]', seq=>$mem_seq++ }, s256
alarm_cause => { type=>'int8[256]', seq=>$mem_seq++ }, s256
video_fifo => { type=>'int8[64]', seq=>$mem_seq++ }, s64
audio_fifo => { type=>'int8[64]', seq=>$mem_seq++ } s64
"""
# ZM 1.36.x SharedData struct format and field names
_STRUCT_FMT_136 = '@IiiIddQIiiiiii????IIIIqqqq256s256s64s64s'
_FIELDS_136 = (
'size last_write_index last_read_index state '
'capture_fps analysis_fps last_event action '
'brightness hue color contrast alarm_x alarm_y '
'valid active signal format '
'imagesize last_frame_score audio_frequency audio_channels '
'startup_time heartbeat_time last_write_time last_read_time '
'control_state alarm_cause video_fifo audio_fifo'
)
_SD_STRING_FIELDS_136 = [
'alarm_cause', 'control_state', 'audio_fifo', 'video_fifo'
]

# ZM 1.38.0+ SharedData struct format and field names
_STRUCT_FMT_138 = '@IiiiIddddQIiiiiii????????IIIIqqqqqq256s256s64s64s64s'
_FIELDS_138 = (
'size last_write_index last_read_index image_count state '
'capture_fps analysis_fps latitude longitude last_event action '
'brightness hue color contrast alarm_x alarm_y '
'valid capturing analysing recording signal format reserved1 reserved2 '
'imagesize last_frame_score audio_frequency audio_channels '
'startup_time heartbeat_time last_write_time last_read_time '
'last_viewed_time last_analysis_viewed_time '
'control_state alarm_cause video_fifo audio_fifo janus_pin'
)
_SD_STRING_FIELDS_138 = [
'alarm_cause', 'control_state', 'audio_fifo', 'video_fifo', 'janus_pin'
]

# Pre-calculate struct sizes for version detection
_SIZE_136 = struct.calcsize(_STRUCT_FMT_136)
_SIZE_138 = struct.calcsize(_STRUCT_FMT_138)

# TriggerData struct (unchanged between versions)
_TRIGGER_FMT = 'IIII32s256s256s'
_TRIGGER_SIZE = struct.calcsize(_TRIGGER_FMT)

"""
trigger_data => { type=>'TriggerData', seq=>$mem_seq++, 'contents'=> {
size => { type=>'uint32', seq=>$mem_seq++ }, I
trigger_state => { type=>'uint32', seq=>$mem_seq++ }, I
trigger_score => { type=>'uint32', seq=>$mem_seq++ }, I
padding => { type=>'uint32', seq=>$mem_seq++ }, I
trigger_cause => { type=>'int8[32]', seq=>$mem_seq++ }, s32
trigger_text => { type=>'int8[256]', seq=>$mem_seq++ }, s256
trigger_showtext => { type=>'int8[256]', seq=>$mem_seq++ }, s256
}
"""

class ZMMemory(Base):

Expand All @@ -82,6 +79,7 @@ def __init__(self,api=None, path='/dev/shm', mid=None):
}
self.fhandle = None
self.mhandle = None
self._zm_version = None # Will be '1.36' or '1.38' after first read

if not mid:
raise ValueError ('No monitor specified')
Expand All @@ -104,6 +102,7 @@ def reload(self):
self.mhandle = mmap.mmap(self.fhandle.fileno(), 0, access=mmap.ACCESS_READ)
self.sd = None
self.td = None
self._zm_version = None
self._read()

def is_valid(self):
Expand Down Expand Up @@ -205,21 +204,70 @@ def trigger(self):

}

def _detect_version(self):
"""Detect ZM version from the size field in SharedData.

The first uint32 in SharedData is the struct size, which differs
between ZM versions:
- ZM 1.36.x: 760 bytes
- ZM 1.38.0+: 872 bytes
"""
self.mhandle.seek(0)
size_bytes = self.mhandle.read(4)
size_val = struct.unpack('@I', size_bytes)[0]
if size_val == _SIZE_138:
self._zm_version = '1.38'
elif size_val == _SIZE_136:
self._zm_version = '1.36'
else:
# Default to 1.36 format but warn
self._zm_version = '1.36'
try:
g.logger.Warning(
'ZMMemory: Unknown SharedData size {} in {}, '
'expected {} (ZM 1.36) or {} (ZM 1.38). '
'Falling back to ZM 1.36 format.'.format(
size_val, self.fname, _SIZE_136, _SIZE_138
)
)
except Exception:
pass

def _read(self):
# Detect version on first read
if self._zm_version is None:
self._detect_version()

self.mhandle.seek(0)
struct_fmt = '@IiiIddQIiiiiii????IIIIqqqq256s256s64s64s'
SharedData = namedtuple('SharedData', 'size last_write_index last_read_index state capture_fps analysis_fps last_event action brightness hue color contrast alarm_x alarm_y valid active signal format imagesize last_frame_score audio_frequency audio_channels startup_time heartbeat_time last_write_time last_read_time control_state alarm_cause video_fifo audio_fifo')
s = SharedData._make(struct.unpack(struct_fmt, self.mhandle.read(struct.calcsize(struct_fmt))))

if self._zm_version == '1.38':
struct_fmt = _STRUCT_FMT_138
fields = _FIELDS_138
string_fields = _SD_STRING_FIELDS_138
else:
struct_fmt = _STRUCT_FMT_136
fields = _FIELDS_136
string_fields = _SD_STRING_FIELDS_136

SharedData = namedtuple('SharedData', fields)
struct_size = struct.calcsize(struct_fmt)
s = SharedData._make(struct.unpack(struct_fmt, self.mhandle.read(struct_size)))

TriggerData = namedtuple('TriggerData', 'size trigger_state trigger_score padding trigger_cause trigger_text trigger_showtext')
t = TriggerData._make(struct.unpack('IIII32s256s256s', self.mhandle.read(560)))
t = TriggerData._make(struct.unpack(_TRIGGER_FMT, self.mhandle.read(_TRIGGER_SIZE)))
self.sd = s._asdict()
self.td = t._asdict()

for key in ['alarm_cause', 'control_state', 'audio_fifo', 'video_fifo']:
self.sd[key] = self.sd[key].split(b'\0',1)[0].decode()
self.td['trigger_cause'] = self.td['trigger_cause'].split(b'\0',1)[0].decode()
self.td['trigger_text'] = self.td['trigger_text'].split(b'\0',1)[0].decode()
self.td['trigger_showtext'] = self.td['trigger_showtext'].split(b'\0',1)[0].decode()
for key in string_fields:
self.sd[key] = self.sd[key].split(b'\0',1)[0].decode(errors='replace')
self.td['trigger_cause'] = self.td['trigger_cause'].split(b'\0',1)[0].decode(errors='replace')
self.td['trigger_text'] = self.td['trigger_text'].split(b'\0',1)[0].decode(errors='replace')
self.td['trigger_showtext'] = self.td['trigger_showtext'].split(b'\0',1)[0].decode(errors='replace')

# For backward compatibility, add 'active' as alias for 'capturing' in ZM 1.38
if self._zm_version == '1.38' and 'capturing' in self.sd:
self.sd['active'] = self.sd['capturing']

return {'shared_data': self.sd, 'trigger_data': self.td}


Expand Down Expand Up @@ -261,5 +309,3 @@ def close(self):
if self.fhandle: self.fhandle.close()
except Exception as e:
pass