1 # 1 #
2 # gdb helper commands and functions for Linux 2 # gdb helper commands and functions for Linux kernel debugging
3 # 3 #
4 # kernel log buffer dump 4 # kernel log buffer dump
5 # 5 #
6 # Copyright (c) Siemens AG, 2011, 2012 6 # Copyright (c) Siemens AG, 2011, 2012
7 # 7 #
8 # Authors: 8 # Authors:
9 # Jan Kiszka <jan.kiszka@siemens.com> 9 # Jan Kiszka <jan.kiszka@siemens.com>
10 # 10 #
11 # This work is licensed under the terms of the 11 # This work is licensed under the terms of the GNU GPL version 2.
12 # 12 #
13 13
14 import gdb 14 import gdb
15 import sys <<
16 15
17 from linux import utils 16 from linux import utils
18 17
19 printk_info_type = utils.CachedType("struct pr <<
20 prb_data_blk_lpos_type = utils.CachedType("str <<
21 prb_desc_type = utils.CachedType("struct prb_d <<
22 prb_desc_ring_type = utils.CachedType("struct <<
23 prb_data_ring_type = utils.CachedType("struct <<
24 printk_ringbuffer_type = utils.CachedType("str <<
25 18
26 class LxDmesg(gdb.Command): 19 class LxDmesg(gdb.Command):
27 """Print Linux kernel log buffer.""" 20 """Print Linux kernel log buffer."""
28 21
29 def __init__(self): 22 def __init__(self):
30 super(LxDmesg, self).__init__("lx-dmes 23 super(LxDmesg, self).__init__("lx-dmesg", gdb.COMMAND_DATA)
31 24
32 def invoke(self, arg, from_tty): 25 def invoke(self, arg, from_tty):
33 inf = gdb.inferiors()[0] !! 26 log_buf_addr = int(str(gdb.parse_and_eval(
>> 27 "'printk.c'::log_buf")).split()[0], 16)
>> 28 log_first_idx = int(gdb.parse_and_eval("'printk.c'::log_first_idx"))
>> 29 log_next_idx = int(gdb.parse_and_eval("'printk.c'::log_next_idx"))
>> 30 log_buf_len = int(gdb.parse_and_eval("'printk.c'::log_buf_len"))
34 31
35 # read in prb structure !! 32 inf = gdb.inferiors()[0]
36 prb_addr = int(str(gdb.parse_and_eval( !! 33 start = log_buf_addr + log_first_idx
37 sz = printk_ringbuffer_type.get_type() !! 34 if log_first_idx < log_next_idx:
38 prb = utils.read_memoryview(inf, prb_a !! 35 log_buf_2nd_half = -1
39 !! 36 length = log_next_idx - log_first_idx
40 # read in descriptor ring structure !! 37 log_buf = utils.read_memoryview(inf, start, length).tobytes()
41 off = printk_ringbuffer_type.get_type( !! 38 else:
42 addr = prb_addr + off !! 39 log_buf_2nd_half = log_buf_len - log_first_idx
43 sz = prb_desc_ring_type.get_type().siz !! 40 a = utils.read_memoryview(inf, start, log_buf_2nd_half)
44 desc_ring = utils.read_memoryview(inf, !! 41 b = utils.read_memoryview(inf, log_buf_addr, log_next_idx)
45 !! 42 log_buf = a.tobytes() + b.tobytes()
46 # read in descriptor count, size, and !! 43
47 off = prb_desc_ring_type.get_type()['c !! 44 pos = 0
48 desc_ring_count = 1 << utils.read_u32( !! 45 while pos < log_buf.__len__():
49 desc_sz = prb_desc_type.get_type().siz !! 46 length = utils.read_u16(log_buf[pos + 8:pos + 10])
50 off = prb_desc_ring_type.get_type()['d !! 47 if length == 0:
51 desc_addr = utils.read_ulong(desc_ring !! 48 if log_buf_2nd_half == -1:
52 !! 49 gdb.write("Corrupted log buffer!\n")
53 # read in info size and address <<
54 info_sz = printk_info_type.get_type(). <<
55 off = prb_desc_ring_type.get_type()['i <<
56 info_addr = utils.read_ulong(desc_ring <<
57 <<
58 # read in text data ring structure <<
59 off = printk_ringbuffer_type.get_type( <<
60 addr = prb_addr + off <<
61 sz = prb_data_ring_type.get_type().siz <<
62 text_data_ring = utils.read_memoryview <<
63 <<
64 # read in text data size and address <<
65 off = prb_data_ring_type.get_type()['s <<
66 text_data_sz = 1 << utils.read_u32(tex <<
67 off = prb_data_ring_type.get_type()['d <<
68 text_data_addr = utils.read_ulong(text <<
69 <<
70 sv_off = prb_desc_type.get_type()['sta <<
71 <<
72 off = prb_desc_type.get_type()['text_b <<
73 begin_off = off + (prb_data_blk_lpos_t <<
74 next_off = off + (prb_data_blk_lpos_ty <<
75 <<
76 ts_off = printk_info_type.get_type()[' <<
77 len_off = printk_info_type.get_type()[ <<
78 <<
79 # definitions from kernel/printk/print <<
80 desc_committed = 1 <<
81 desc_finalized = 2 <<
82 desc_sv_bits = utils.get_long_type().s <<
83 desc_flags_shift = desc_sv_bits - 2 <<
84 desc_flags_mask = 3 << desc_flags_shif <<
85 desc_id_mask = ~desc_flags_mask <<
86 <<
87 # read in tail and head descriptor ids <<
88 off = prb_desc_ring_type.get_type()['t <<
89 tail_id = utils.read_atomic_long(desc_ <<
90 off = prb_desc_ring_type.get_type()['h <<
91 head_id = utils.read_atomic_long(desc_ <<
92 <<
93 did = tail_id <<
94 while True: <<
95 ind = did % desc_ring_count <<
96 desc_off = desc_sz * ind <<
97 info_off = info_sz * ind <<
98 <<
99 desc = utils.read_memoryview(inf, <<
100 <<
101 # skip non-committed record <<
102 state = 3 & (utils.read_atomic_lon <<
103 if state != desc_committed and sta <<
104 if did == head_id: <<
105 break 50 break
106 did = (did + 1) & desc_id_mask !! 51 pos = log_buf_2nd_half
107 continue 52 continue
108 53
109 begin = utils.read_ulong(desc, beg !! 54 text_len = utils.read_u16(log_buf[pos + 10:pos + 12])
110 end = utils.read_ulong(desc, next_ !! 55 text = log_buf[pos + 16:pos + 16 + text_len].decode()
111 !! 56 time_stamp = utils.read_u64(log_buf[pos:pos + 8])
112 info = utils.read_memoryview(inf, <<
113 <<
114 # handle data-less record <<
115 if begin & 1 == 1: <<
116 text = "" <<
117 else: <<
118 # handle wrapping data block <<
119 if begin > end: <<
120 begin = 0 <<
121 <<
122 # skip over descriptor id <<
123 text_start = begin + utils.get <<
124 <<
125 text_len = utils.read_u16(info <<
126 <<
127 # handle truncated message <<
128 if end - text_start < text_len <<
129 text_len = end - text_star <<
130 <<
131 text_data = utils.read_memoryv <<
132 <<
133 text = text_data[0:text_len].d <<
134 <<
135 time_stamp = utils.read_u64(info, <<
136 57
137 for line in text.splitlines(): 58 for line in text.splitlines():
138 msg = u"[{time:12.6f}] {line}\ !! 59 gdb.write("[{time:12.6f}] {line}\n".format(
139 time=time_stamp / 10000000 60 time=time_stamp / 1000000000.0,
140 line=line) !! 61 line=line))
141 # With python2 gdb.write will !! 62
142 # ascii and might fail so pass !! 63 pos += length
143 if sys.hexversion < 0x03000000 <<
144 msg = msg.encode(encoding= <<
145 gdb.write(msg) <<
146 <<
147 if did == head_id: <<
148 break <<
149 did = (did + 1) & desc_id_mask <<
150 64
151 65
152 LxDmesg() 66 LxDmesg()
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