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
249
250
251
252
253
|
/*
* Copyright 2014, Michael Ellerman, IBM Corp.
* Licensed under GPLv2.
*/
#define _GNU_SOURCE /* For CPU_ZERO etc. */
#include <errno.h>
#include <sched.h>
#include <setjmp.h>
#include <stdlib.h>
#include <sys/wait.h>
#include "utils.h"
#include "lib.h"
int pick_online_cpu(void)
{
cpu_set_t mask;
int cpu;
CPU_ZERO(&mask);
if (sched_getaffinity(0, sizeof(mask), &mask)) {
perror("sched_getaffinity");
return -1;
}
/* We prefer a primary thread, but skip 0 */
for (cpu = 8; cpu < CPU_SETSIZE; cpu += 8)
if (CPU_ISSET(cpu, &mask))
return cpu;
/* Search for anything, but in reverse */
for (cpu = CPU_SETSIZE - 1; cpu >= 0; cpu--)
if (CPU_ISSET(cpu, &mask))
return cpu;
printf("No cpus in affinity mask?!\n");
return -1;
}
int bind_to_cpu(int cpu)
{
cpu_set_t mask;
printf("Binding to cpu %d\n", cpu);
CPU_ZERO(&mask);
CPU_SET(cpu, &mask);
return sched_setaffinity(0, sizeof(mask), &mask);
}
#define PARENT_TOKEN 0xAA
#define CHILD_TOKEN 0x55
int sync_with_child(union pipe read_pipe, union pipe write_pipe)
{
char c = PARENT_TOKEN;
FAIL_IF(write(write_pipe.write_fd, &c, 1) != 1);
FAIL_IF(read(read_pipe.read_fd, &c, 1) != 1);
if (c != CHILD_TOKEN) /* sometimes expected */
return 1;
return 0;
}
int wait_for_parent(union pipe read_pipe)
{
char c;
FAIL_IF(read(read_pipe.read_fd, &c, 1) != 1);
FAIL_IF(c != PARENT_TOKEN);
return 0;
}
int notify_parent(union pipe write_pipe)
{
char c = CHILD_TOKEN;
FAIL_IF(write(write_pipe.write_fd, &c, 1) != 1);
return 0;
}
int notify_parent_of_error(union pipe write_pipe)
{
char c = ~CHILD_TOKEN;
FAIL_IF(write(write_pipe.write_fd, &c, 1) != 1);
return 0;
}
int wait_for_child(pid_t child_pid)
{
int rc;
if (waitpid(child_pid, &rc, 0) == -1) {
perror("waitpid");
return 1;
}
if (WIFEXITED(rc))
rc = WEXITSTATUS(rc);
else
rc = 1; /* Signal or other */
return rc;
}
int kill_child_and_wait(pid_t child_pid)
{
kill(child_pid, SIGTERM);
return wait_for_child(child_pid);
}
static int eat_cpu_child(union pipe read_pipe, union pipe write_pipe)
{
volatile int i = 0;
/*
* We are just here to eat cpu and die. So make sure we can be killed,
* and also don't do any custom SIGTERM handling.
*/
signal(SIGTERM, SIG_DFL);
notify_parent(write_pipe);
wait_for_parent(read_pipe);
/* Soak up cpu forever */
while (1) i++;
return 0;
}
pid_t eat_cpu(int (test_function)(void))
{
union pipe read_pipe, write_pipe;
int cpu, rc;
pid_t pid;
cpu = pick_online_cpu();
FAIL_IF(cpu < 0);
FAIL_IF(bind_to_cpu(cpu));
if (pipe(read_pipe.fds) == -1)
return -1;
if (pipe(write_pipe.fds) == -1)
return -1;
pid = fork();
if (pid == 0)
exit(eat_cpu_child(write_pipe, read_pipe));
if (sync_with_child(read_pipe, write_pipe)) {
rc = -1;
goto out;
}
printf("main test running as pid %d\n", getpid());
rc = test_function();
out:
kill(pid, SIGKILL);
return rc;
}
struct addr_range libc, vdso;
int parse_proc_maps(void)
{
unsigned long start, end;
char execute, name[128];
FILE *f;
int rc;
f = fopen("/proc/self/maps", "r");
if (!f) {
perror("fopen");
return -1;
}
do {
/* This skips line with no executable which is what we want */
rc = fscanf(f, "%lx-%lx %*c%*c%c%*c %*x %*d:%*d %*d %127s\n",
&start, &end, &execute, name);
if (rc <= 0)
break;
if (execute != 'x')
continue;
if (strstr(name, "libc")) {
libc.first = start;
libc.last = end - 1;
} else if (strstr(name, "[vdso]")) {
vdso.first = start;
vdso.last = end - 1;
}
} while(1);
fclose(f);
return 0;
}
#define PARANOID_PATH "/proc/sys/kernel/perf_event_paranoid"
bool require_paranoia_below(int level)
{
unsigned long current;
char *end, buf[16];
FILE *f;
int rc;
rc = -1;
f = fopen(PARANOID_PATH, "r");
if (!f) {
perror("fopen");
goto out;
}
if (!fgets(buf, sizeof(buf), f)) {
printf("Couldn't read " PARANOID_PATH "?\n");
goto out_close;
}
current = strtoul(buf, &end, 10);
if (end == buf) {
printf("Couldn't parse " PARANOID_PATH "?\n");
goto out_close;
}
if (current >= level)
goto out;
rc = 0;
out_close:
fclose(f);
out:
return rc;
}
|
