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@pawlos

pawlos/parser.py

Created Aug 11, 2017
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The parser for gdb remote protocol
import sys
readingMem = False
addr = 0x0
def decode(m):
result = ""
index = 0
while '*' in m:
n_index = m.index('*')
result += m[0:n_index]
what = m[n_index-1]
how_many = ord(m[n_index+1]) - 29
result += what * how_many
m = m[n_index+2:]
index = n_index+1
return result+m[0:]
def readMem(m):
global readingMem
global addr
checksum = m[1:].index('#')
split = m[1:1+checksum].split(',')
print 'Reading memory at: 0x'+split[0]+' of 0x'+split[1]+' bytes'
readingMem = True #if '55555555' in split[0] else False
addr = int(split[0],16)
#print 'Addr: ',addr
def readRegs(x):
print 'Reading registers', x
def qSymbol(x):
checksum = x.index('#')
x = x[0:checksum]
x = x.replace('qSymbol','')
x = x.replace(':','')
#print 'q: ',decode(x)
return decode(x).decode('hex')
def vFile(x):
option = x[6:x.index(':',6)]
if option == 'open':
#print 'vfile:',x[11:x.index(',')]
return 'open: '+x[11:x.index(',')].decode('hex')+" "+x[x.index(','):]
return x
with open('data.file') as f, open('a.out','wb') as g:
data = f.read()
packets = data.split('$')
mappings = {
'!': lambda x: sys.stdout.write('Extended mode, '+x+'\n'),
'+': lambda x: sys.stdout.write(''),
'm': lambda x: readMem(x),
'g': lambda x: readRegs(x),
'qSymbol': lambda x: sys.stdout.write('qSymbol: '+qSymbol(x)+'\n'),#[8:].decode('hex'),
'qSupported': lambda x: sys.stdout.write(x),
'PacketSize': lambda x: sys.stdout.write(x),
'vFile': lambda x: sys.stdout.write('File: '+vFile(x)+'\n')
}
for p in packets:
packet_type = p[0]
if packet_type in mappings:
mappings[packet_type](p)
continue
else:
if ':' in p:
packet_type = p[0:p.index(':')]
if packet_type in mappings:
mappings[packet_type](p)
continue
data = decode(p[:p.index('#')])
sys.stdout.write('Unk: '+data+'\n')
base = 0x555555554000
if readingMem:
readingMem = False
if '55555555' in hex(addr):
sys.stdout.write('Saving @: '+str(addr-base)+'\n')
g.seek(addr-base)
g.write(data.decode('hex'))
try:
sys.stdout.write(data.decode('hex')+'\n')
except:
pass
sys.stdout.flush()
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