forked from bloomberg/pystack
-
Notifications
You must be signed in to change notification settings - Fork 0
Expand file tree
/
Copy pathmaps.py
More file actions
327 lines (280 loc) · 10.1 KB
/
maps.py
File metadata and controls
327 lines (280 loc) · 10.1 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
import collections
import dataclasses
import logging
import os
import re
from pathlib import Path
from typing import Any
from typing import Dict
from typing import Iterable
from typing import List
from typing import Optional
from .errors import MissingExecutableMaps
from .errors import ProcessNotFound
from .errors import PystackError
LOGGER = logging.getLogger(__file__)
MAPS_REGEXP = re.compile(
r"""
(?P<start>[\da-f]+)
-
(?P<end>[\da-f]+)
\s
(?P<permissions>....)
\s
(?P<offset>[\da-f]+)
\s
(?P<dev>[\da-f][\da-f]+:[\da-f][\da-f]+)
\s
(?P<inode>\d+)
\s*
(?P<pathname>.+)?
$
""",
re.VERBOSE,
)
RawCoreMapList = List[Dict[str, Any]]
@dataclasses.dataclass(frozen=True, eq=True)
class VirtualMap:
start: int
end: int
filesize: int
offset: int
device: str
flags: str
inode: int
path: Optional[Path]
def contains(self, addr: int) -> bool:
return self.start <= addr < self.end
def is_executable(self) -> bool:
return "x" in self.flags
def is_readable(self) -> bool:
return "r" in self.flags
def is_writable(self) -> bool:
return "w" in self.flags
def is_private(self) -> bool:
return "p" in self.flags
@property
def size(self) -> int:
return self.end - self.start
def __repr__(self) -> str:
start = f"0x{self.start:016x}"
end = f"0x{self.end:016x}"
filesize = f"0x{self.filesize:x}"
offset = f"0x{self.offset:x}"
return (
f"VirtualMap(start={start!s}, end={end!s},"
f" filesize={filesize!s}, offset={offset!s},"
f" device={self.device!r}, flags={self.flags!r}, inode={self.inode!r},"
f" path={str(self.path)!r})"
)
@dataclasses.dataclass
class MemoryRange:
min_addr: int
max_addr: int
@dataclasses.dataclass
class MemoryMapInformation:
memory: MemoryRange
heap: Optional[VirtualMap]
bss: Optional[VirtualMap]
python: VirtualMap
libpython: Optional[VirtualMap]
def _read_maps(pid: int) -> List[str]:
try:
with open(f"/proc/{pid}/maps") as maps:
return maps.readlines()
except FileNotFoundError:
raise ProcessNotFound(f"No such process id: {pid}") from None
def generate_maps_for_process(pid: int) -> Iterable[VirtualMap]:
proc_maps_lines = _read_maps(pid)
for index, line in enumerate(proc_maps_lines):
line = line.rstrip("\n")
match = MAPS_REGEXP.match(line)
if not match:
LOGGER.debug("Line %r cannot be recognized!", line)
continue
path = match.group("pathname")
yield VirtualMap(
start=int(match.group("start"), 16),
end=int(match.group("end"), 16),
filesize=int(match.group("end"), 16) - int(match.group("start"), 16),
offset=int(match.group("offset"), 16),
device=match.group("dev"),
flags=match.group("permissions"),
inode=int(match.group("inode")),
path=Path(path) if path else None,
)
def generate_maps_from_core_data(
mapped_files: RawCoreMapList, memory_maps: RawCoreMapList
) -> Iterable[VirtualMap]:
memory_map_ranges = {(map["start"], map["end"]) for map in memory_maps}
missing_mapped_files = [
map
for map in mapped_files
if (map["start"], map["end"]) not in memory_map_ranges
]
all_maps: RawCoreMapList = sorted(
memory_maps + missing_mapped_files, key=lambda map: map["start"]
)
# Some paths in the mapped files can be absolute, but we need to work with the canonical
# paths that the linker reported, so we need to "unresolve" those path back to whatever
# the memory math paths are so we can properly group then together. For example, the map
# for the interpreter may be "/usr/bin/python" in the mapped files and "/venv/bin/python"
# in the memory maps.
missing_map_paths = {
Path(map["path"]) for map in missing_mapped_files if map is not None
}
file_maps = {}
for map in memory_maps:
if not map["path"]:
continue
the_path = Path(map["path"])
resolved_path = the_path.resolve()
if resolved_path in missing_map_paths:
file_maps[resolved_path] = the_path
for data_elem in all_maps:
path = Path(data_elem["path"]) if data_elem["path"] else None
if path is not None:
path = file_maps.get(path, path)
yield VirtualMap(
start=data_elem["start"],
end=data_elem["end"],
filesize=data_elem["filesize"],
offset=data_elem["offset"],
device=data_elem["device"],
flags=data_elem["flags"],
inode=data_elem["inode"],
path=path,
)
def parse_maps_file(pid: int, all_maps: Iterable[VirtualMap]) -> MemoryMapInformation:
binary_name = Path(os.readlink(f"/proc/{pid}/exe"))
return parse_maps_file_for_binary(binary_name, all_maps)
def _get_base_map(binary_maps: List[VirtualMap]) -> VirtualMap:
maybe_map = next(
(map for map in binary_maps if map.path is not None),
None,
)
if maybe_map is not None:
return maybe_map
first_map, *_ = binary_maps
return first_map
def _get_bss(elf_maps: List[VirtualMap], load_point: int) -> Optional[VirtualMap]:
binary_map = _get_base_map(elf_maps)
if not binary_map or not binary_map.path:
return None
try:
from ._pystack import get_bss_info
except ImportError: # pragma: no cover
return None
bss_info = get_bss_info(binary_map.path)
if not bss_info:
return None
start = load_point + bss_info["corrected_addr"]
LOGGER.info(
"Determined exact addr of .bss section: %s (%s + %s)",
hex(start),
hex(load_point),
hex(bss_info["corrected_addr"]),
)
offset = 0
# Calculate the offset based on the mapped files. The offset in core files
# is only present in the core (and not in the original ELF) so this
# operation allows us to correlate the bss section with some memory location
# within the core file.
first_matching_map = next((map for map in elf_maps if map.contains(start)), None)
if first_matching_map is None:
return None
offset = first_matching_map.offset + (start - first_matching_map.start)
bss = VirtualMap(
start=start,
end=start + bss_info["size"],
filesize=bss_info["size"],
offset=offset,
device="",
flags="",
inode=0,
path=None,
)
return bss
def parse_maps_file_for_binary(
binary_name: Path,
all_maps_iter: Iterable[VirtualMap],
load_point_by_module: Optional[Dict[str, int]] = None,
) -> MemoryMapInformation:
min_addr = float("inf")
max_addr = 0
maps_by_library: Dict[str, List[VirtualMap]] = collections.defaultdict(list)
current_lib = ""
all_maps = tuple(all_maps_iter)
if load_point_by_module is None:
load_point_by_module = collections.defaultdict(lambda: 2**64)
for memory_range in all_maps:
if memory_range.path is not None:
load_point_by_module[memory_range.path.name] = min(
memory_range.start,
load_point_by_module[memory_range.path.name],
)
for memory_range in all_maps:
current_lib = (
memory_range.path.name if memory_range.path is not None else current_lib
)
maps_by_library[current_lib].append(memory_range)
if memory_range.path is None or not memory_range.path.name.startswith("[v"):
min_addr = min(min_addr, memory_range.start)
max_addr = max(max_addr, memory_range.end)
maps_by_library = dict(maps_by_library)
python = libpython = bss = heap = None
try:
binary_maps = maps_by_library[binary_name.name]
python = _get_base_map(binary_maps)
except KeyError:
LOGGER.debug("Unable to find maps for %r in %r", binary_name, maps_by_library)
available_maps = {
str(map.path)
for map in all_maps
if map.path is not None and ".so" not in map.path.name
}
LOGGER.debug("Available executable maps: %s", ", ".join(available_maps))
if available_maps:
maps_txt = ", ".join(available_maps)
msg = f"These are the available executable memory maps: {maps_txt}"
else:
msg = "There are no available executable maps with known paths."
raise MissingExecutableMaps(
f"Unable to find maps for the executable {binary_name}. " + msg
)
LOGGER.info("python binary first map found: %r", python)
libpython_binaries = [lib for lib in maps_by_library if "libpython" in lib]
if len(libpython_binaries) > 1:
raise PystackError(
f"Unexpectedly found multiple libpython in process: {libpython_binaries}"
)
elif len(libpython_binaries) == 1:
libpython_name = libpython_binaries[0]
libpython_maps = maps_by_library[libpython_name]
load_point = load_point_by_module[libpython_name]
elf_maps = libpython_maps
libpython = _get_base_map(libpython_maps)
LOGGER.info("%r first map found: %r", libpython_name, libpython)
else:
LOGGER.info("Process does not have a libpython.so, reading from binary")
elf_maps = binary_maps
libpython = None
load_point = load_point_by_module[binary_name.name]
heap_maps = maps_by_library.get("[heap]")
if heap_maps is not None:
*_, heap = [m for m in heap_maps if getattr(m.path, "name", None) == "[heap]"]
LOGGER.info("Heap map found: %r", heap)
bss = _get_bss(elf_maps, load_point)
if bss is None:
bss = (
next(
(map for map in elf_maps if map.path is None and map.is_readable()),
None,
)
if elf_maps
else None
)
if bss:
LOGGER.info("bss map found: %r", bss)
memory = MemoryRange(min_addr=int(min_addr), max_addr=int(max_addr))
return MemoryMapInformation(memory, heap, bss, python, libpython)