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 15 16from linux import utils 17 18 19class LxDmesg(gdb.Command): 20 """Print Linux kernel log buffer.""" 21 22 def __init__(self): 23 super(LxDmesg, self).__init__("lx-dmesg", gdb.COMMAND_DATA) 24 25 def invoke(self, arg, from_tty): 26 log_buf_addr = int(str(gdb.parse_and_eval("log_buf")).split()[0], 16) 27 log_first_idx = int(gdb.parse_and_eval("log_first_idx")) 28 log_next_idx = int(gdb.parse_and_eval("log_next_idx")) 29 log_buf_len = int(gdb.parse_and_eval("log_buf_len")) 30 31 inf = gdb.inferiors()[0] 32 start = log_buf_addr + log_first_idx 33 if log_first_idx < log_next_idx: 34 log_buf_2nd_half = -1 35 length = log_next_idx - log_first_idx 36 log_buf = inf.read_memory(start, length) 37 else: 38 log_buf_2nd_half = log_buf_len - log_first_idx 39 log_buf = inf.read_memory(start, log_buf_2nd_half) + \ 40 inf.read_memory(log_buf_addr, log_next_idx) 41 42 pos = 0 43 while pos < log_buf.__len__(): 44 length = utils.read_u16(log_buf[pos + 8:pos + 10]) 45 if length == 0: 46 if log_buf_2nd_half == -1: 47 gdb.write("Corrupted log buffer!\n") 48 break 49 pos = log_buf_2nd_half 50 continue 51 52 text_len = utils.read_u16(log_buf[pos + 10:pos + 12]) 53 text = log_buf[pos + 16:pos + 16 + text_len] 54 time_stamp = utils.read_u64(log_buf[pos:pos + 8]) 55 56 for line in memoryview(text).tobytes().splitlines(): 57 gdb.write("[{time:12.6f}] {line}\n".format( 58 time=time_stamp / 1000000000.0, 59 line=line)) 60 61 pos += length 62 63 64LxDmesg() 65