1# 2# gdb helper commands and functions for Linux kernel debugging 3# 4# kernel log buffer dump 5# 6# Copyright (c) Siemens AG, 2011, 2012 7# 8# Authors: 9# Jan Kiszka <jan.kiszka@siemens.com> 10# 11# This work is licensed under the terms of the GNU GPL version 2. 12# 13 14import gdb 15import string 16 17from linux import utils 18 19 20class LxDmesg(gdb.Command): 21 """Print Linux kernel log buffer.""" 22 23 def __init__(self): 24 super(LxDmesg, self).__init__("lx-dmesg", gdb.COMMAND_DATA) 25 26 def invoke(self, arg, from_tty): 27 log_buf_addr = int(str(gdb.parse_and_eval("log_buf")).split()[0], 16) 28 log_first_idx = int(gdb.parse_and_eval("log_first_idx")) 29 log_next_idx = int(gdb.parse_and_eval("log_next_idx")) 30 log_buf_len = int(gdb.parse_and_eval("log_buf_len")) 31 32 inf = gdb.inferiors()[0] 33 start = log_buf_addr + log_first_idx 34 if log_first_idx < log_next_idx: 35 log_buf_2nd_half = -1 36 length = log_next_idx - log_first_idx 37 log_buf = inf.read_memory(start, length) 38 else: 39 log_buf_2nd_half = log_buf_len - log_first_idx 40 log_buf = inf.read_memory(start, log_buf_2nd_half) + \ 41 inf.read_memory(log_buf_addr, log_next_idx) 42 43 pos = 0 44 while pos < log_buf.__len__(): 45 length = utils.read_u16(log_buf[pos + 8:pos + 10]) 46 if length == 0: 47 if log_buf_2nd_half == -1: 48 gdb.write("Corrupted log buffer!\n") 49 break 50 pos = log_buf_2nd_half 51 continue 52 53 text_len = utils.read_u16(log_buf[pos + 10:pos + 12]) 54 text = log_buf[pos + 16:pos + 16 + text_len] 55 time_stamp = utils.read_u64(log_buf[pos:pos + 8]) 56 57 for line in memoryview(text).tobytes().splitlines(): 58 gdb.write("[{time:12.6f}] {line}\n".format( 59 time=time_stamp / 1000000000.0, 60 line=line)) 61 62 pos += length 63 64 65LxDmesg() 66