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
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
|
/*
* probe-event.c : perf-probe definition to kprobe_events format converter
*
* Written by Masami Hiramatsu <mhiramat@redhat.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
*/
#define _GNU_SOURCE
#include <sys/utsname.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <errno.h>
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#undef _GNU_SOURCE
#include "event.h"
#include "string.h"
#include "debug.h"
#include "parse-events.h" /* For debugfs_path */
#include "probe-event.h"
#define MAX_CMDLEN 256
#define MAX_PROBE_ARGS 128
#define PERFPROBE_GROUP "probe"
#define semantic_error(msg ...) die("Semantic error :" msg)
/* Parse probepoint definition. */
static void parse_perf_probe_probepoint(char *arg, struct probe_point *pp)
{
char *ptr, *tmp;
char c, nc = 0;
/*
* <Syntax>
* perf probe SRC:LN
* perf probe FUNC[+OFFS|%return][@SRC]
*/
ptr = strpbrk(arg, ":+@%");
if (ptr) {
nc = *ptr;
*ptr++ = '\0';
}
/* Check arg is function or file and copy it */
if (strchr(arg, '.')) /* File */
pp->file = strdup(arg);
else /* Function */
pp->function = strdup(arg);
DIE_IF(pp->file == NULL && pp->function == NULL);
/* Parse other options */
while (ptr) {
arg = ptr;
c = nc;
ptr = strpbrk(arg, ":+@%");
if (ptr) {
nc = *ptr;
*ptr++ = '\0';
}
switch (c) {
case ':': /* Line number */
pp->line = strtoul(arg, &tmp, 0);
if (*tmp != '\0')
semantic_error("There is non-digit charactor"
" in line number.");
break;
case '+': /* Byte offset from a symbol */
pp->offset = strtoul(arg, &tmp, 0);
if (*tmp != '\0')
semantic_error("There is non-digit charactor"
" in offset.");
break;
case '@': /* File name */
if (pp->file)
semantic_error("SRC@SRC is not allowed.");
pp->file = strdup(arg);
DIE_IF(pp->file == NULL);
if (ptr)
semantic_error("@SRC must be the last "
"option.");
break;
case '%': /* Probe places */
if (strcmp(arg, "return") == 0) {
pp->retprobe = 1;
} else /* Others not supported yet */
semantic_error("%%%s is not supported.", arg);
break;
default:
DIE_IF("Program has a bug.");
break;
}
}
/* Exclusion check */
if (pp->line && pp->offset)
semantic_error("Offset can't be used with line number.");
if (!pp->line && pp->file && !pp->function)
semantic_error("File always requires line number.");
if (pp->offset && !pp->function)
semantic_error("Offset requires an entry function.");
if (pp->retprobe && !pp->function)
semantic_error("Return probe requires an entry function.");
if ((pp->offset || pp->line) && pp->retprobe)
semantic_error("Offset/Line can't be used with return probe.");
pr_debug("symbol:%s file:%s line:%d offset:%d, return:%d\n",
pp->function, pp->file, pp->line, pp->offset, pp->retprobe);
}
/* Parse perf-probe event definition */
int parse_perf_probe_event(const char *str, struct probe_point *pp)
{
char **argv;
int argc, i, need_dwarf = 0;
argv = argv_split(str, &argc);
if (!argv)
die("argv_split failed.");
if (argc > MAX_PROBE_ARGS + 1)
semantic_error("Too many arguments");
/* Parse probe point */
parse_perf_probe_probepoint(argv[0], pp);
if (pp->file || pp->line)
need_dwarf = 1;
/* Copy arguments and ensure return probe has no C argument */
pp->nr_args = argc - 1;
pp->args = zalloc(sizeof(char *) * pp->nr_args);
for (i = 0; i < pp->nr_args; i++) {
pp->args[i] = strdup(argv[i + 1]);
if (!pp->args[i])
die("Failed to copy argument.");
if (is_c_varname(pp->args[i])) {
if (pp->retprobe)
semantic_error("You can't specify local"
" variable for kretprobe");
need_dwarf = 1;
}
}
argv_free(argv);
return need_dwarf;
}
int synthesize_trace_kprobe_event(struct probe_point *pp)
{
char *buf;
int i, len, ret;
pp->probes[0] = buf = zalloc(MAX_CMDLEN);
if (!buf)
die("Failed to allocate memory by zalloc.");
ret = snprintf(buf, MAX_CMDLEN, "%s+%d", pp->function, pp->offset);
if (ret <= 0 || ret >= MAX_CMDLEN)
goto error;
len = ret;
for (i = 0; i < pp->nr_args; i++) {
ret = snprintf(&buf[len], MAX_CMDLEN - len, " %s",
pp->args[i]);
if (ret <= 0 || ret >= MAX_CMDLEN - len)
goto error;
len += ret;
}
pp->found = 1;
return pp->found;
error:
free(pp->probes[0]);
if (ret > 0)
ret = -E2BIG;
return ret;
}
static int write_trace_kprobe_event(int fd, const char *buf)
{
int ret;
ret = write(fd, buf, strlen(buf));
if (ret <= 0)
die("Failed to create event.");
else
printf("Added new event: %s\n", buf);
return ret;
}
void add_trace_kprobe_events(struct probe_point *probes, int nr_probes)
{
int i, j, fd;
struct probe_point *pp;
char buf[MAX_CMDLEN];
snprintf(buf, MAX_CMDLEN, "%s/../kprobe_events", debugfs_path);
fd = open(buf, O_WRONLY, O_APPEND);
if (fd < 0) {
if (errno == ENOENT)
die("kprobe_events file does not exist -"
" please rebuild with CONFIG_KPROBE_TRACER.");
else
die("Could not open kprobe_events file: %s",
strerror(errno));
}
for (j = 0; j < nr_probes; j++) {
pp = probes + j;
if (pp->found == 1) {
snprintf(buf, MAX_CMDLEN, "%c:%s/%s_%x %s\n",
pp->retprobe ? 'r' : 'p', PERFPROBE_GROUP,
pp->function, pp->offset, pp->probes[0]);
write_trace_kprobe_event(fd, buf);
} else
for (i = 0; i < pp->found; i++) {
snprintf(buf, MAX_CMDLEN, "%c:%s/%s_%x_%d %s\n",
pp->retprobe ? 'r' : 'p',
PERFPROBE_GROUP,
pp->function, pp->offset, i,
pp->probes[i]);
write_trace_kprobe_event(fd, buf);
}
}
close(fd);
}
|
