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
|
// SPDX-License-Identifier: GPL-2.0
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <errno.h>
#include <fcntl.h>
#include <poll.h>
#include <unistd.h>
#include <linux/perf_event.h>
#include <sys/mman.h>
#include "trace_helpers.h"
#define DEBUGFS "/sys/kernel/debug/tracing/"
#define MAX_SYMS 300000
static struct ksym syms[MAX_SYMS];
static int sym_cnt;
static int ksym_cmp(const void *p1, const void *p2)
{
return ((struct ksym *)p1)->addr - ((struct ksym *)p2)->addr;
}
int load_kallsyms(void)
{
FILE *f = fopen("/proc/kallsyms", "r");
char func[256], buf[256];
char symbol;
void *addr;
int i = 0;
if (!f)
return -ENOENT;
while (fgets(buf, sizeof(buf), f)) {
if (sscanf(buf, "%p %c %s", &addr, &symbol, func) != 3)
break;
if (!addr)
continue;
syms[i].addr = (long) addr;
syms[i].name = strdup(func);
i++;
}
fclose(f);
sym_cnt = i;
qsort(syms, sym_cnt, sizeof(struct ksym), ksym_cmp);
return 0;
}
struct ksym *ksym_search(long key)
{
int start = 0, end = sym_cnt;
int result;
/* kallsyms not loaded. return NULL */
if (sym_cnt <= 0)
return NULL;
while (start < end) {
size_t mid = start + (end - start) / 2;
result = key - syms[mid].addr;
if (result < 0)
end = mid;
else if (result > 0)
start = mid + 1;
else
return &syms[mid];
}
if (start >= 1 && syms[start - 1].addr < key &&
key < syms[start].addr)
/* valid ksym */
return &syms[start - 1];
/* out of range. return _stext */
return &syms[0];
}
long ksym_get_addr(const char *name)
{
int i;
for (i = 0; i < sym_cnt; i++) {
if (strcmp(syms[i].name, name) == 0)
return syms[i].addr;
}
return 0;
}
/* open kallsyms and read symbol addresses on the fly. Without caching all symbols,
* this is faster than load + find.
*/
int kallsyms_find(const char *sym, unsigned long long *addr)
{
char type, name[500];
unsigned long long value;
int err = 0;
FILE *f;
f = fopen("/proc/kallsyms", "r");
if (!f)
return -EINVAL;
while (fscanf(f, "%llx %c %499s%*[^\n]\n", &value, &type, name) > 0) {
if (strcmp(name, sym) == 0) {
*addr = value;
goto out;
}
}
err = -ENOENT;
out:
fclose(f);
return err;
}
void read_trace_pipe(void)
{
int trace_fd;
trace_fd = open(DEBUGFS "trace_pipe", O_RDONLY, 0);
if (trace_fd < 0)
return;
while (1) {
static char buf[4096];
ssize_t sz;
sz = read(trace_fd, buf, sizeof(buf) - 1);
if (sz > 0) {
buf[sz] = 0;
puts(buf);
}
}
}
|
