1 /* SPDX-License-Identifier: GPL-2.0 */
7 #include <linux/limits.h>
13 #include <sys/types.h>
17 #include "cgroup_util.h"
19 static ssize_t read_text(const char *path, char *buf, size_t max_len)
24 fd = open(path, O_RDONLY);
28 len = read(fd, buf, max_len - 1);
38 static ssize_t write_text(const char *path, char *buf, ssize_t len)
42 fd = open(path, O_WRONLY | O_APPEND);
46 len = write(fd, buf, len);
57 char *cg_name(const char *root, const char *name)
59 size_t len = strlen(root) + strlen(name) + 2;
60 char *ret = malloc(len);
62 snprintf(ret, len, "%s/%s", root, name);
67 char *cg_name_indexed(const char *root, const char *name, int index)
69 size_t len = strlen(root) + strlen(name) + 10;
70 char *ret = malloc(len);
72 snprintf(ret, len, "%s/%s_%d", root, name, index);
77 int cg_read(const char *cgroup, const char *control, char *buf, size_t len)
81 snprintf(path, sizeof(path), "%s/%s", cgroup, control);
83 if (read_text(path, buf, len) >= 0)
89 int cg_read_strcmp(const char *cgroup, const char *control,
96 /* Handle the case of comparing against empty string */
100 size = strlen(expected) + 1;
106 if (cg_read(cgroup, control, buf, size)) {
111 ret = strcmp(expected, buf);
116 int cg_read_strstr(const char *cgroup, const char *control, const char *needle)
120 if (cg_read(cgroup, control, buf, sizeof(buf)))
123 return strstr(buf, needle) ? 0 : -1;
126 long cg_read_long(const char *cgroup, const char *control)
130 if (cg_read(cgroup, control, buf, sizeof(buf)))
136 long cg_read_key_long(const char *cgroup, const char *control, const char *key)
141 if (cg_read(cgroup, control, buf, sizeof(buf)))
144 ptr = strstr(buf, key);
148 return atol(ptr + strlen(key));
151 int cg_write(const char *cgroup, const char *control, char *buf)
154 ssize_t len = strlen(buf);
156 snprintf(path, sizeof(path), "%s/%s", cgroup, control);
158 if (write_text(path, buf, len) == len)
164 int cg_find_unified_root(char *root, size_t len)
166 char buf[10 * PAGE_SIZE];
167 char *fs, *mount, *type;
168 const char delim[] = "\n\t ";
170 if (read_text("/proc/self/mounts", buf, sizeof(buf)) <= 0)
175 * cgroup /sys/fs/cgroup cgroup2 rw,seclabel,noexec,relatime 0 0
177 for (fs = strtok(buf, delim); fs; fs = strtok(NULL, delim)) {
178 mount = strtok(NULL, delim);
179 type = strtok(NULL, delim);
184 if (strcmp(fs, "cgroup") == 0 &&
185 strcmp(type, "cgroup2") == 0) {
186 strncpy(root, mount, len);
194 int cg_create(const char *cgroup)
196 return mkdir(cgroup, 0644);
199 static int cg_killall(const char *cgroup)
204 if (cg_read(cgroup, "cgroup.procs", buf, sizeof(buf)))
207 while (ptr < buf + sizeof(buf)) {
208 int pid = strtol(ptr, &ptr, 10);
216 if (kill(pid, SIGKILL))
223 int cg_destroy(const char *cgroup)
229 if (ret && errno == EBUSY) {
230 ret = cg_killall(cgroup);
237 if (ret && errno == ENOENT)
243 int cg_enter_current(const char *cgroup)
247 snprintf(pidbuf, sizeof(pidbuf), "%d", getpid());
248 return cg_write(cgroup, "cgroup.procs", pidbuf);
251 int cg_run(const char *cgroup,
252 int (*fn)(const char *cgroup, void *arg),
260 } else if (pid == 0) {
263 snprintf(buf, sizeof(buf), "%d", getpid());
264 if (cg_write(cgroup, "cgroup.procs", buf))
266 exit(fn(cgroup, arg));
268 waitpid(pid, &retcode, 0);
269 if (WIFEXITED(retcode))
270 return WEXITSTATUS(retcode);
276 int cg_run_nowait(const char *cgroup,
277 int (*fn)(const char *cgroup, void *arg),
286 snprintf(buf, sizeof(buf), "%d", getpid());
287 if (cg_write(cgroup, "cgroup.procs", buf))
289 exit(fn(cgroup, arg));
295 int get_temp_fd(void)
297 return open(".", O_TMPFILE | O_RDWR | O_EXCL);
300 int alloc_pagecache(int fd, size_t size)
311 if (ftruncate(fd, size))
314 for (i = 0; i < size; i += sizeof(buf))
315 read(fd, buf, sizeof(buf));
323 int alloc_anon(const char *cgroup, void *arg)
325 size_t size = (unsigned long)arg;
329 for (ptr = buf; ptr < buf + size; ptr += PAGE_SIZE)
336 int is_swap_enabled(void)
339 const char delim[] = "\n";
343 if (read_text("/proc/swaps", buf, sizeof(buf)) <= 0)
346 for (line = strtok(buf, delim); line; line = strtok(NULL, delim))
352 int set_oom_adj_score(int pid, int score)
357 sprintf(path, "/proc/%d/oom_score_adj", pid);
359 fd = open(path, O_WRONLY | O_APPEND);
363 len = dprintf(fd, "%d", score);