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#! /usr/bin/python
import os
import sys
import string
import re
## hash from symbol name to list of symbols with that name,
## where the list of symbols contains a list representing each symbol
symbols = {}
roots = {}
def createBacklinks(name, syms):
for s in syms:
refs = s[2]
for r in refs:
## for each ref, add ourselves as a referencer
if symbols.has_key(r):
targets = symbols[r]
for t in targets:
if name not in t[5]:
t[5].append(name)
def markSymbol(frm, name):
if not symbols.has_key(name):
print "%s referenced but was not in the objdump"
syms = symbols[name]
## print ambiguous references unless they are internal noise like ".L129"
if len(syms) > 1 and name[0] != '.':
print "Reference to symbol '%s' from '%s' is ambiguous, marking all '%s'" % (name, frm, name)
print syms
for s in syms:
if s[4]:
pass ## already marked
else:
s[4] = 1
refs = s[2]
for r in refs:
markSymbol(s[0], r)
def cmpFilename(a, b):
v = cmp(a[1], b[1])
if v == 0:
v = cmp(a[0], b[0])
return v
def sizeAsString(bytes):
if bytes < 1024:
return "%d bytes" % bytes
elif bytes < 1024*1024:
return "%.2gK" % (bytes / 1024.0)
else:
return "%.2gM" % (bytes / 1024.0 / 1024.0)
def printLost():
list = []
filename = None
for (name, syms) in symbols.items():
s = syms[0] ## we always mark all or none for now
if not s[4] and name[0] != '.': ## skip .L129 type symbols
filename = s[3]
if not filename:
filename = "unknown file"
list.append ((name, filename, s[5], s[7]))
file_summaries = []
total_unused = 0
total_this_file = 0
filename = None
list.sort(cmpFilename)
for l in list:
next_filename = l[1]
if next_filename != filename:
if total_this_file > 0:
file_summaries.append (" %s may be unused in %s" % (sizeAsString(total_this_file), filename))
print "%s has these symbols not reachable from exported symbols:" % next_filename
filename = next_filename
total_this_file = 0
print " %s %s" % (l[0], sizeAsString(l[3]))
total_unused = total_unused + l[3]
total_this_file = total_this_file + l[3]
for trace in l[2]:
print " referenced from %s" % trace
for fs in file_summaries:
print fs
print "%s total may be unused" % sizeAsString(total_unused)
def main():
## 0001aa44 <_dbus_message_get_network_data>:
sym_re = re.compile ('([0-9a-f]+) <([^>]+)>:')
## 1aa49: e8 00 00 00 00 call 1aa4e <_dbus_message_get_network_data+0xa>
ref_re = re.compile (' <([^>]+)> *$')
## /home/hp/dbus-cvs/dbus/dbus/dbus-message.c:139
file_re = re.compile ('^(\/[^:].*):[0-9]+$')
## _dbus_message_get_network_data+0xa
funcname_re = re.compile ('([^+]+)\+[0-9a-fx]+')
## 00005410 T dbus_address_entries_free
dynsym_re = re.compile ('T ([^ \n]+)$')
filename = sys.argv[1]
command = """
objdump -D --demangle -l %s
""" % filename
command = string.strip (command)
print "Running: %s" % command
f = os.popen(command)
## first we find which functions reference which other functions
current_sym = None
lines = f.readlines()
for l in lines:
addr = None
name = None
target = None
file = None
match = sym_re.match(l)
if match:
addr = match.group(1)
name = match.group(2)
else:
match = ref_re.search(l)
if match:
target = match.group(1)
else:
match = file_re.match(l)
if match:
file = match.group(1)
if name:
## 0 symname, 1 address, 2 references, 3 filename, 4 reached, 5 referenced-by 6 backlinked 7 approx size
item = [name, addr, [], None, 0, [], 0, 0]
if symbols.has_key(name):
symbols[name].append(item)
else:
symbols[name] = [item]
if current_sym:
prev_addr = long(current_sym[1], 16)
our_addr = long(item[1], 16)
item[7] = our_addr - prev_addr
if item[7] < 0:
print "Computed negative size %d for %s" % (item[7], item[0])
item[7] = 0
current_sym = item
elif target and current_sym:
match = funcname_re.match(target)
if match:
## dump the "+address"
target = match.group(1)
if target == current_sym[0]:
pass ## skip self-references
else:
current_sym[2].append (target)
elif file and current_sym:
if file.startswith('/usr/include'):
## inlined libc thingy
pass
elif current_sym[0].startswith('.debug'):
## debug info
pass
elif current_sym[3] and current_sym[3] != file:
raise Exception ("%s in both %s and %s" % (current_sym[0], current_sym[3], file))
else:
current_sym[3] = file
## now we need to find the roots (exported symbols)
command = "nm -D %s" % filename
print "Running: %s" % command
f = os.popen(command)
lines = f.readlines ()
for l in lines:
match = dynsym_re.search(l)
if match:
name = match.group(1)
if roots.has_key(name):
raise Exception("symbol %s exported twice?" % name)
else:
roots[name] = 1
print "%d symbols exported from this object" % len(roots)
## these functions are used only indirectly, so we don't
## notice they are used. Manually add them as roots...
vtable_roots = ['unix_finalize',
'unix_handle_watch',
'unix_disconnect',
'unix_connection_set',
'unix_do_iteration',
'unix_live_messages_changed',
'unix_get_unix_fd',
'handle_client_data_cookie_sha1_mech',
'handle_client_data_external_mech',
'handle_server_data_cookie_sha1_mech',
'handle_server_data_external_mech',
'handle_client_initial_response_cookie_sha1_mech',
'handle_client_initial_response_external_mech',
'handle_client_shutdown_cookie_sha1_mech',
'handle_client_shutdown_external_mech',
'handle_server_shutdown_cookie_sha1_mech',
'handle_server_shutdown_external_mech'
]
for vr in vtable_roots:
if roots.has_key(vr):
raise Exception("%s is already a root" % vr)
roots[vr] = 1
for k in roots.keys():
markSymbol("root", k)
for (k, v) in symbols.items():
createBacklinks(k, v)
print """
The symbols mentioned below don't appear to be reachable starting from
the dynamic exports of the library. However, this program is pretty
dumb; a limitation that creates false positives is that it can only
trace 'reachable' through hardcoded function calls, if a function is
called only through a vtable, it won't be marked reachable (and
neither will its children in the call graph).
Also, the sizes mentioned are more or less completely bogus.
"""
print "The following are hardcoded in as vtable roots: %s" % vtable_roots
printLost()
if __name__ == "__main__":
main()
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