matos/custom_gdb_extension.py

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from gdb.printing import PrettyPrinter, register_pretty_printer
import gdb
class KthreadPrettyPrinter(object):
def __init__(self, val):
self.val = val
def to_string(self):
result = ""
name = self.val["name"]
state = self.val["state"]
# Should get PC on stack for non-current thread otherwise will only get address in cpu_context_switch
cpuState = self.val["cpuState"]
cmdline = "info line *%s"%int(cpuState["eip"].cast(gdb.lookup_type("long").pointer()))
line = gdb.execute(cmdline, to_string=True)
#line = gdb.find_pc_line(int(cpuState["eip"].cast(gdb.lookup_type("long").pointer()).referenced_value()))
currentThread = gdb.parse_and_eval("currentThread")
if self.val == currentThread:
result += "->"
else:
result += " "
result += "Addr: 0x%x, name: %s, state: %s, PC: %s" % (self.val, name, state, line)
return result
class CustomPrettyPrinterLocator(PrettyPrinter):
"""Given a gdb.Value, search for a custom pretty printer"""
def __init__(self):
super(CustomPrettyPrinterLocator, self).__init__(
"matos_pretty_printers", []
)
def __call__(self, val):
"""Return the custom formatter if the type can be handled"""
typename = gdb.types.get_basic_type(val.type).tag
if typename is None:
typename = val.type.name
if typename == "kthread":
return KthreadPrettyPrinter(val)
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class KthreadListDumpCmd(gdb.Command):
"""Prints the kthread list"""
def __init__(self):
super(KthreadListDumpCmd, self).__init__(
"kthread_list_dump", gdb.COMMAND_USER
)
def _kthread_list_to_str(self, val):
"""Walk through the Kthread list.
We will simply follow the 'next' pointers until we encounter the HEAD again
"""
idx = 0
head = val
kthread_ptr = val
result = ""
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while kthread_ptr != 0 and (idx == 0 or kthread_ptr != head):
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result += "\n%d: %s" % (idx, KthreadPrettyPrinter(kthread_ptr).to_string())
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kthread_ptr = kthread_ptr["next"]
idx += 1
result = ("Found a Linked List with %d kthread:" % idx) + result
return result
def complete(self, text, word):
# We expect the argument passed to be a symbol so fallback to the
# internal tab-completion handler for symbols
return gdb.COMPLETE_SYMBOL
def invoke(self, args, from_tty):
# We can pass args here and use Python CLI utilities like argparse
# to do argument parsing
print("Args Passed: %s" % args)
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if args:
kthread_ptr_val = gdb.parse_and_eval(args)
else:
kthread_ptr_val = gdb.parse_and_eval("currentThread")
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if str(kthread_ptr_val.type) != "struct kthread *":
print("Expected pointer argument of type (struct kthread *)")
return
print(self._kthread_list_to_str(kthread_ptr_val))
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class PhyMemDescListDumpCmd(gdb.Command):
"""Prints the memDesc list"""
def __init__(self):
super(PhyMemDescListDumpCmd, self).__init__(
"phyMem_list_dump", gdb.COMMAND_USER)
def _phy_memDesc_lit_to_str(self, val):
result = ""
idx = 0
head = val
memDesc_ptr = val
prevAddr = None
printBegin = True
memAddrs = []
while memDesc_ptr != 0 and (idx == 0 or memDesc_ptr != head):
memAddrs.append(int(memDesc_ptr["phy_addr"]))
memDesc_ptr = memDesc_ptr["next"]
idx += 1
memAddrs.sort()
for currAddr in memAddrs:
if printBegin:
prevAddr = currAddr
result += "[0x%x" % prevAddr
printBegin = False
if currAddr > prevAddr + 4096:
result += "->0x%x[\n[0x%x" % ((prevAddr+4096), currAddr)
prevAddr = currAddr
if prevAddr:
result += "->0x%x[\n" % (prevAddr+4096)
result = ("Found a List with %d memDesc:\n" % idx) + result
return result
def complete(self, text, word):
return gdb.COMPLETE_SYMBOL
def invoke(self, args, from_tty):
if args:
desc = gdb.parse_and_eval(args)
else:
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desc = gdb.parse_and_eval("phyFreePage")
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if str(desc.type) != "struct memDesc *":
print("Expected pointer argument of type (struct memDesc *)")
return
print(self._phy_memDesc_lit_to_str(desc))
class PrintStructC99Cmd(gdb.Command):
def __init__(self):
super(PrintStructC99Cmd, self).__init__(
"print_struct_c99",
gdb.COMMAND_USER,
)
def complete(self, text, word):
return gdb.COMPLETE_SYMBOL
def get_count_heading(self, string):
for i, s in enumerate(string):
if s != ' ':
break
return i
def extract_typename(self, string):
first_line = string.split('\n')[0]
return first_line.split('=')[1][:-1].strip()
def invoke(self, arg, from_tty):
gdb.execute("set print pretty")
gdb.execute('set pagination off')
gdb.execute('set print repeats 0')
gdb.execute('set print elements unlimited')
ret_ptype = gdb.execute('ptype {}'.format(arg), to_string=True)
tname = self.extract_typename(ret_ptype)
print('{} {} = {{'.format(tname, arg))
r = gdb.execute('p {}'.format(arg), to_string=True)
r = r.split('\n')
for rr in r[1:]:
if '=' not in rr:
print(rr)
continue
hs = self.get_count_heading(rr)
rr_s = rr.strip().split('=', 1)
rr_rval = rr_s[1].strip()
print(' ' * hs + '.' + rr_s[0] + '= ' + rr_rval)
class ListDumpCmd(gdb.Command):
"""Prints a linked list"""
def __init__(self):
super(ListDumpCmd, self).__init__(
"list_dump", gdb.COMMAND_USER
)
def _print_list(self, val):
"""Walk through the linked list.
We will simply follow the 'next' pointers until we encounter the HEAD again
"""
idx = 0
head = val
kthread_ptr = val
result = ""
while kthread_ptr != 0 and (idx == 0 or kthread_ptr != head):
result += gdb.execute('p *({}){}'.format(str(kthread_ptr.type),kthread_ptr), to_string=True)
kthread_ptr = kthread_ptr["next"]
idx += 1
result = ("Found a Linked List with %d items:" % idx) + "\n"+ result
return result
def complete(self, text, word):
# We expect the argument passed to be a symbol so fallback to the
# internal tab-completion handler for symbols
return gdb.COMPLETE_SYMBOL
def invoke(self, args, from_tty):
# We can pass args here and use Python CLI utilities like argparse
# to do argument parsing
print("Args Passed: %s" % args)
if args:
ptr_val = gdb.parse_and_eval(args)
else:
ptr_val = gdb.parse_and_eval("currentThread")
try:
ptr_val["next"]
except:
print("Expected pointer argument with a next field")
return
print(self._print_list(ptr_val))
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register_pretty_printer(None, CustomPrettyPrinterLocator(), replace=True)
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KthreadListDumpCmd()
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PhyMemDescListDumpCmd()
PrintStructC99Cmd()
ListDumpCmd()