1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
|
/* Copyright (C) 2005-2020 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public License as
published by the Free Software Foundation; either version 2.1 of the
License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#include <stdio.h>
#include <string.h>
#include <sysdep.h>
#include <signal.h>
#include <execinfo.h>
extern int
_identify_sighandler (unsigned long fp, unsigned long pc,
unsigned long *pprev_fp, unsigned long *pprev_pc,
unsigned long *retaddr);
static inline long
get_frame_size (unsigned long instr)
{
return abs ((short signed) (instr & 0xFFFF));
}
static unsigned long *
find_frame_creation (unsigned long *pc)
{
int i;
/* NOTE: Distance to search is arbitrary.
250 works well for most things,
750 picks up things like tcp_recvmsg,
1000 needed for fat_fill_super. */
for (i = 0; i < 1000; i++, pc--)
{
unsigned long instr;
unsigned long frame_size;
instr = *pc;
/* Is the instruction of the form
addik r1, r1, foo ? */
if ((instr & 0xFFFF0000) != 0x30210000)
continue;
frame_size = get_frame_size (instr);
if ((frame_size < 8) || (frame_size & 3))
return NULL;
return pc;
}
return NULL;
}
static int
lookup_prev_stack_frame (unsigned long fp, unsigned long pc,
unsigned long *pprev_fp, unsigned long *pprev_pc,
unsigned long *retaddr)
{
unsigned long *prologue = NULL;
int is_signalhandler = _identify_sighandler (fp, pc, pprev_fp,
pprev_pc, retaddr);
if (!is_signalhandler)
{
prologue = find_frame_creation ((unsigned long *) pc);
if (prologue)
{
long frame_size = get_frame_size (*prologue);
*pprev_fp = fp + frame_size;
if (*retaddr != 0)
*pprev_pc = *retaddr;
else
*pprev_pc = *(unsigned long *) fp;
*retaddr = 0;
if (!*pprev_pc || (*pprev_pc & 3))
prologue=0;
}
else
{
*pprev_pc = 0;
*pprev_fp = fp;
*retaddr = 0;
}
}
return (!*pprev_pc || (*pprev_pc & 3)) ? -1 : 0;
}
int
__backtrace (void **array, int size)
{
unsigned long pc, fp;
unsigned long ppc, pfp;
/* Return address(r15) is required in the signal handler case, since the
return address of the function which causes the signal may not be
recorded in the stack. */
unsigned long retaddr;
int count;
int rc = 0;
if (size <= 0)
return 0;
__asm__ __volatile__ ("mfs %0, rpc"
: "=r"(pc));
__asm__ __volatile__ ("add %0, r1, r0"
: "=r"(fp));
array[0] = (void *) pc;
retaddr = 0;
for (count = 1; count < size; count++)
{
rc = lookup_prev_stack_frame (fp, pc, &pfp, &ppc, &retaddr);
fp = pfp;
pc = ppc;
array[count] = (void *) pc;
if (rc)
return count;
}
return count;
}
weak_alias (__backtrace, backtrace)
libc_hidden_def (__backtrace)
|
