| Andrew Scull | b4b6d4a | 2019-01-02 15:54:55 +0000 | [diff] [blame^] | 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 | |
| 14 | import gdb |
| 15 | import sys |
| 16 | |
| 17 | from linux import utils |
| 18 | |
| 19 | |
| 20 | class 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( |
| 28 | "(void *)'printk.c'::log_buf")).split()[0], 16) |
| 29 | log_first_idx = int(gdb.parse_and_eval("'printk.c'::log_first_idx")) |
| 30 | log_next_idx = int(gdb.parse_and_eval("'printk.c'::log_next_idx")) |
| 31 | log_buf_len = int(gdb.parse_and_eval("'printk.c'::log_buf_len")) |
| 32 | |
| 33 | inf = gdb.inferiors()[0] |
| 34 | start = log_buf_addr + log_first_idx |
| 35 | if log_first_idx < log_next_idx: |
| 36 | log_buf_2nd_half = -1 |
| 37 | length = log_next_idx - log_first_idx |
| 38 | log_buf = utils.read_memoryview(inf, start, length).tobytes() |
| 39 | else: |
| 40 | log_buf_2nd_half = log_buf_len - log_first_idx |
| 41 | a = utils.read_memoryview(inf, start, log_buf_2nd_half) |
| 42 | b = utils.read_memoryview(inf, log_buf_addr, log_next_idx) |
| 43 | log_buf = a.tobytes() + b.tobytes() |
| 44 | |
| 45 | pos = 0 |
| 46 | while pos < log_buf.__len__(): |
| 47 | length = utils.read_u16(log_buf[pos + 8:pos + 10]) |
| 48 | if length == 0: |
| 49 | if log_buf_2nd_half == -1: |
| 50 | gdb.write("Corrupted log buffer!\n") |
| 51 | break |
| 52 | pos = log_buf_2nd_half |
| 53 | continue |
| 54 | |
| 55 | text_len = utils.read_u16(log_buf[pos + 10:pos + 12]) |
| 56 | text = log_buf[pos + 16:pos + 16 + text_len].decode( |
| 57 | encoding='utf8', errors='replace') |
| 58 | time_stamp = utils.read_u64(log_buf[pos:pos + 8]) |
| 59 | |
| 60 | for line in text.splitlines(): |
| 61 | msg = u"[{time:12.6f}] {line}\n".format( |
| 62 | time=time_stamp / 1000000000.0, |
| 63 | line=line) |
| 64 | # With python2 gdb.write will attempt to convert unicode to |
| 65 | # ascii and might fail so pass an utf8-encoded str instead. |
| 66 | if sys.hexversion < 0x03000000: |
| 67 | msg = msg.encode(encoding='utf8', errors='replace') |
| 68 | gdb.write(msg) |
| 69 | |
| 70 | pos += length |
| 71 | |
| 72 | |
| 73 | LxDmesg() |