| # |
| # gdb helper commands and functions for Linux kernel debugging |
| # |
| # kernel log buffer dump |
| # |
| # Copyright (c) Siemens AG, 2011, 2012 |
| # |
| # Authors: |
| # Jan Kiszka <jan.kiszka@siemens.com> |
| # |
| # This work is licensed under the terms of the GNU GPL version 2. |
| # |
| |
| import gdb |
| import sys |
| |
| from linux import utils |
| |
| printk_log_type = utils.CachedType("struct printk_log") |
| |
| |
| class LxDmesg(gdb.Command): |
| """Print Linux kernel log buffer.""" |
| |
| def __init__(self): |
| super(LxDmesg, self).__init__("lx-dmesg", gdb.COMMAND_DATA) |
| |
| def invoke(self, arg, from_tty): |
| log_buf_addr = int(str(gdb.parse_and_eval( |
| "(void *)'printk.c'::log_buf")).split()[0], 16) |
| log_first_idx = int(gdb.parse_and_eval("'printk.c'::log_first_idx")) |
| log_next_idx = int(gdb.parse_and_eval("'printk.c'::log_next_idx")) |
| log_buf_len = int(gdb.parse_and_eval("'printk.c'::log_buf_len")) |
| |
| inf = gdb.inferiors()[0] |
| start = log_buf_addr + log_first_idx |
| if log_first_idx < log_next_idx: |
| log_buf_2nd_half = -1 |
| length = log_next_idx - log_first_idx |
| log_buf = utils.read_memoryview(inf, start, length).tobytes() |
| else: |
| log_buf_2nd_half = log_buf_len - log_first_idx |
| a = utils.read_memoryview(inf, start, log_buf_2nd_half) |
| b = utils.read_memoryview(inf, log_buf_addr, log_next_idx) |
| log_buf = a.tobytes() + b.tobytes() |
| |
| length_offset = printk_log_type.get_type()['len'].bitpos // 8 |
| text_len_offset = printk_log_type.get_type()['text_len'].bitpos // 8 |
| time_stamp_offset = printk_log_type.get_type()['ts_nsec'].bitpos // 8 |
| text_offset = printk_log_type.get_type().sizeof |
| |
| pos = 0 |
| while pos < log_buf.__len__(): |
| length = utils.read_u16(log_buf, pos + length_offset) |
| if length == 0: |
| if log_buf_2nd_half == -1: |
| gdb.write("Corrupted log buffer!\n") |
| break |
| pos = log_buf_2nd_half |
| continue |
| |
| text_len = utils.read_u16(log_buf, pos + text_len_offset) |
| text_start = pos + text_offset |
| text = log_buf[text_start:text_start + text_len].decode( |
| encoding='utf8', errors='replace') |
| time_stamp = utils.read_u64(log_buf, pos + time_stamp_offset) |
| |
| for line in text.splitlines(): |
| msg = u"[{time:12.6f}] {line}\n".format( |
| time=time_stamp / 1000000000.0, |
| line=line) |
| # With python2 gdb.write will attempt to convert unicode to |
| # ascii and might fail so pass an utf8-encoded str instead. |
| if sys.hexversion < 0x03000000: |
| msg = msg.encode(encoding='utf8', errors='replace') |
| gdb.write(msg) |
| |
| pos += length |
| |
| |
| LxDmesg() |
