GDB Mozilla symbol server
# Any copyright is dedicated to the Public Domain. | |
# http://creativecommons.org/publicdomain/zero/1.0/ | |
# | |
# A GDB Python script to fetch debug symbols from the Mozilla symbol server. | |
# | |
# To use, run `source /path/to/symbols.py` in GDB 7.9 or newer, or | |
# put that in your ~/.gdbinit. | |
from __future__ import print_function | |
import gzip | |
import io | |
import itertools | |
import os | |
import shutil | |
import sys | |
try: | |
from urllib.request import urlopen | |
from urllib.parse import urljoin, quote | |
except ImportError: | |
from urllib2 import urlopen | |
from urllib import quote | |
from urlparse import urljoin | |
SYMBOL_SERVER_URL = 'https://s3-us-west-2.amazonaws.com/org.mozilla.crash-stats.symbols-public/v1/' | |
debug_dir = os.path.join(os.environ['HOME'], '.cache', 'gdb') | |
cache_dir = os.path.join(debug_dir, '.build-id') | |
def munge_build_id(build_id): | |
''' | |
Breakpad stuffs the build id into a GUID struct so the bytes are | |
flipped from the standard presentation. | |
''' | |
b = list(map(''.join, list(zip(*[iter(build_id.upper())]*2)))) | |
return ''.join(itertools.chain(reversed(b[:4]), reversed(b[4:6]), | |
reversed(b[6:8]), b[8:16])) + '0' | |
def try_fetch_symbols(filename, build_id, destination): | |
debug_file = os.path.join(destination, build_id[:2], build_id[2:] + '.debug') | |
if os.path.exists(debug_file): | |
return debug_file | |
try: | |
d = os.path.dirname(debug_file) | |
if not os.path.isdir(d): | |
os.makedirs(d) | |
except OSError: | |
pass | |
path = os.path.join(filename, munge_build_id(build_id), filename + '.dbg.gz') | |
url = urljoin(SYMBOL_SERVER_URL, quote(path)) | |
try: | |
u = urlopen(url) | |
if u.getcode() != 200: | |
return None | |
print('Fetching symbols from {0}'.format(url)) | |
with open(debug_file, 'wb') as f, gzip.GzipFile(fileobj=io.BytesIO(u.read()), mode='r') as z: | |
shutil.copyfileobj(z, f) | |
return debug_file | |
except: | |
return None | |
def is_moz_binary(filename): | |
''' | |
Try to determine if a file lives in a Firefox install dir, to save | |
HTTP requests for things that aren't going to work. | |
''' | |
# The linux-gate VDSO doesn't have a real filename. | |
if not os.path.isfile(filename): | |
return False | |
while True: | |
filename = os.path.dirname(filename) | |
if filename == '/': | |
return False | |
if os.path.isfile(os.path.join(filename, 'application.ini')): | |
return True | |
def fetch_symbols_for(objfile): | |
build_id = objfile.build_id if hasattr(objfile, 'build_id') else None | |
if getattr(objfile, 'owner', None) is not None or any(o.owner == objfile for o in gdb.objfiles()): | |
# This is either a separate debug file or this file already | |
# has symbols in a separate debug file. | |
return | |
if build_id and is_moz_binary(objfile.filename): | |
debug_file = try_fetch_symbols(os.path.basename(objfile.filename), build_id, cache_dir) | |
if debug_file: | |
objfile.add_separate_debug_file(debug_file) | |
def new_objfile(event): | |
fetch_symbols_for(event.new_objfile) | |
def fetch_symbols(): | |
''' | |
Try to fetch symbols for all loaded modules. | |
''' | |
for objfile in gdb.objfiles(): | |
fetch_symbols_for(objfile) | |
# Create our debug cache dir. | |
try: | |
if not os.path.isdir(cache_dir): | |
os.makedirs(cache_dir) | |
except OSError: | |
pass | |
# Set it as a debug-file-directory. | |
try: | |
dirs = gdb.parameter('debug-file-directory').split(':') | |
except gdb.error: | |
dirs = [] | |
if debug_dir not in dirs: | |
dirs.append(debug_dir) | |
gdb.execute('set debug-file-directory %s' % ':'.join(dirs)) | |
gdb.events.new_objfile.connect(new_objfile) |
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Thanks! That hang on startup had been driving me nuts but I never got around to investigating it! |
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symbols.mozilla.org is switching to GCP soon. One of the consequences of that is that it'll no longer be saving uploaded symbols to that S3 bucket. I suggest switching to |
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I got an infinite loop in
def is_moz_binary(filename):
with anobjfile.filename
that issystem-supplied DSO at 0x7fff4939b000
. Stripping dirnames from that lead to an empty string.I changed it like this: