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
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
|
/* SPDX-License-Identifier: GPL-2.0 */
#define _GNU_SOURCE
#include <errno.h>
#include <fcntl.h>
#include <linux/limits.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
#include "cgroup_util.h"
static ssize_t read_text(const char *path, char *buf, size_t max_len)
{
ssize_t len;
int fd;
fd = open(path, O_RDONLY);
if (fd < 0)
return fd;
len = read(fd, buf, max_len - 1);
if (len < 0)
goto out;
buf[len] = 0;
out:
close(fd);
return len;
}
static ssize_t write_text(const char *path, char *buf, ssize_t len)
{
int fd;
fd = open(path, O_WRONLY | O_APPEND);
if (fd < 0)
return fd;
len = write(fd, buf, len);
if (len < 0) {
close(fd);
return len;
}
close(fd);
return len;
}
char *cg_name(const char *root, const char *name)
{
size_t len = strlen(root) + strlen(name) + 2;
char *ret = malloc(len);
snprintf(ret, len, "%s/%s", root, name);
return ret;
}
char *cg_name_indexed(const char *root, const char *name, int index)
{
size_t len = strlen(root) + strlen(name) + 10;
char *ret = malloc(len);
snprintf(ret, len, "%s/%s_%d", root, name, index);
return ret;
}
int cg_read(const char *cgroup, const char *control, char *buf, size_t len)
{
char path[PATH_MAX];
snprintf(path, sizeof(path), "%s/%s", cgroup, control);
if (read_text(path, buf, len) >= 0)
return 0;
return -1;
}
int cg_read_strcmp(const char *cgroup, const char *control,
const char *expected)
{
size_t size;
char *buf;
int ret;
/* Handle the case of comparing against empty string */
if (!expected)
size = 32;
else
size = strlen(expected) + 1;
buf = malloc(size);
if (!buf)
return -1;
if (cg_read(cgroup, control, buf, size)) {
free(buf);
return -1;
}
ret = strcmp(expected, buf);
free(buf);
return ret;
}
int cg_read_strstr(const char *cgroup, const char *control, const char *needle)
{
char buf[PAGE_SIZE];
if (cg_read(cgroup, control, buf, sizeof(buf)))
return -1;
return strstr(buf, needle) ? 0 : -1;
}
long cg_read_long(const char *cgroup, const char *control)
{
char buf[128];
if (cg_read(cgroup, control, buf, sizeof(buf)))
return -1;
return atol(buf);
}
long cg_read_key_long(const char *cgroup, const char *control, const char *key)
{
char buf[PAGE_SIZE];
char *ptr;
if (cg_read(cgroup, control, buf, sizeof(buf)))
return -1;
ptr = strstr(buf, key);
if (!ptr)
return -1;
return atol(ptr + strlen(key));
}
int cg_write(const char *cgroup, const char *control, char *buf)
{
char path[PATH_MAX];
ssize_t len = strlen(buf);
snprintf(path, sizeof(path), "%s/%s", cgroup, control);
if (write_text(path, buf, len) == len)
return 0;
return -1;
}
int cg_find_unified_root(char *root, size_t len)
{
char buf[10 * PAGE_SIZE];
char *fs, *mount, *type;
const char delim[] = "\n\t ";
if (read_text("/proc/self/mounts", buf, sizeof(buf)) <= 0)
return -1;
/*
* Example:
* cgroup /sys/fs/cgroup cgroup2 rw,seclabel,noexec,relatime 0 0
*/
for (fs = strtok(buf, delim); fs; fs = strtok(NULL, delim)) {
mount = strtok(NULL, delim);
type = strtok(NULL, delim);
strtok(NULL, delim);
strtok(NULL, delim);
strtok(NULL, delim);
if (strcmp(fs, "cgroup") == 0 &&
strcmp(type, "cgroup2") == 0) {
strncpy(root, mount, len);
return 0;
}
}
return -1;
}
int cg_create(const char *cgroup)
{
return mkdir(cgroup, 0644);
}
static int cg_killall(const char *cgroup)
{
char buf[PAGE_SIZE];
char *ptr = buf;
if (cg_read(cgroup, "cgroup.procs", buf, sizeof(buf)))
return -1;
while (ptr < buf + sizeof(buf)) {
int pid = strtol(ptr, &ptr, 10);
if (pid == 0)
break;
if (*ptr)
ptr++;
else
break;
if (kill(pid, SIGKILL))
return -1;
}
return 0;
}
int cg_destroy(const char *cgroup)
{
int ret;
retry:
ret = rmdir(cgroup);
if (ret && errno == EBUSY) {
ret = cg_killall(cgroup);
if (ret)
return ret;
usleep(100);
goto retry;
}
if (ret && errno == ENOENT)
ret = 0;
return ret;
}
int cg_enter_current(const char *cgroup)
{
char pidbuf[64];
snprintf(pidbuf, sizeof(pidbuf), "%d", getpid());
return cg_write(cgroup, "cgroup.procs", pidbuf);
}
int cg_run(const char *cgroup,
int (*fn)(const char *cgroup, void *arg),
void *arg)
{
int pid, retcode;
pid = fork();
if (pid < 0) {
return pid;
} else if (pid == 0) {
char buf[64];
snprintf(buf, sizeof(buf), "%d", getpid());
if (cg_write(cgroup, "cgroup.procs", buf))
exit(EXIT_FAILURE);
exit(fn(cgroup, arg));
} else {
waitpid
|