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 char *cg_control(const char *cgroup, const char *control)
79 size_t len = strlen(cgroup) + strlen(control) + 2;
80 char *ret = malloc(len);
82 snprintf(ret, len, "%s/%s", cgroup, control);
87 int cg_read(const char *cgroup, const char *control, char *buf, size_t len)
91 snprintf(path, sizeof(path), "%s/%s", cgroup, control);
93 if (read_text(path, buf, len) >= 0)
99 int cg_read_strcmp(const char *cgroup, const char *control,
100 const char *expected)
106 /* Handle the case of comparing against empty string */
110 size = strlen(expected) + 1;
116 if (cg_read(cgroup, control, buf, size)) {
121 ret = strcmp(expected, buf);
126 int cg_read_strstr(const char *cgroup, const char *control, const char *needle)
130 if (cg_read(cgroup, control, buf, sizeof(buf)))
133 return strstr(buf, needle) ? 0 : -1;
136 long cg_read_long(const char *cgroup, const char *control)
140 if (cg_read(cgroup, control, buf, sizeof(buf)))
146 long cg_read_key_long(const char *cgroup, const char *control, const char *key)
151 if (cg_read(cgroup, control, buf, sizeof(buf)))
154 ptr = strstr(buf, key);
158 return atol(ptr + strlen(key));
161 long cg_read_lc(const char *cgroup, const char *control)
164 const char delim[] = "\n";
168 if (cg_read(cgroup, control, buf, sizeof(buf)))
171 for (line = strtok(buf, delim); line; line = strtok(NULL, delim))
177 int cg_write(const char *cgroup, const char *control, char *buf)
180 ssize_t len = strlen(buf);
182 snprintf(path, sizeof(path), "%s/%s", cgroup, control);
184 if (write_text(path, buf, len) == len)
190 int cg_find_unified_root(char *root, size_t len)
192 char buf[10 * PAGE_SIZE];
193 char *fs, *mount, *type;
194 const char delim[] = "\n\t ";
196 if (read_text("/proc/self/mounts", buf, sizeof(buf)) <= 0)
201 * cgroup /sys/fs/cgroup cgroup2 rw,seclabel,noexec,relatime 0 0
203 for (fs = strtok(buf, delim); fs; fs = strtok(NULL, delim)) {
204 mount = strtok(NULL, delim);
205 type = strtok(NULL, delim);
210 if (strcmp(type, "cgroup2") == 0) {
211 strncpy(root, mount, len);
219 int cg_create(const char *cgroup)
221 return mkdir(cgroup, 0644);
224 int cg_wait_for_proc_count(const char *cgroup, int count)
226 char buf[10 * PAGE_SIZE] = {0};
230 for (attempts = 10; attempts >= 0; attempts--) {
233 if (cg_read(cgroup, "cgroup.procs", buf, sizeof(buf)))
236 for (ptr = buf; *ptr; ptr++)
249 int cg_killall(const char *cgroup)
254 if (cg_read(cgroup, "cgroup.procs", buf, sizeof(buf)))
257 while (ptr < buf + sizeof(buf)) {
258 int pid = strtol(ptr, &ptr, 10);
266 if (kill(pid, SIGKILL))
273 int cg_destroy(const char *cgroup)
279 if (ret && errno == EBUSY) {
285 if (ret && errno == ENOENT)
291 int cg_enter(const char *cgroup, int pid)
295 snprintf(pidbuf, sizeof(pidbuf), "%d", pid);
296 return cg_write(cgroup, "cgroup.procs", pidbuf);
299 int cg_enter_current(const char *cgroup)
301 return cg_write(cgroup, "cgroup.procs", "0");
304 int cg_enter_current_thread(const char *cgroup)
306 return cg_write(cgroup, "cgroup.threads", "0");
309 int cg_run(const char *cgroup,
310 int (*fn)(const char *cgroup, void *arg),
318 } else if (pid == 0) {
321 snprintf(buf, sizeof(buf), "%d", getpid());
322 if (cg_write(cgroup, "cgroup.procs", buf))
324 exit(fn(cgroup, arg));
326 waitpid(pid, &retcode, 0);
327 if (WIFEXITED(retcode))
328 return WEXITSTATUS(retcode);
334 int cg_run_nowait(const char *cgroup,
335 int (*fn)(const char *cgroup, void *arg),
344 snprintf(buf, sizeof(buf), "%d", getpid());
345 if (cg_write(cgroup, "cgroup.procs", buf))
347 exit(fn(cgroup, arg));
353 int get_temp_fd(void)
355 return open(".", O_TMPFILE | O_RDWR | O_EXCL);
358 int alloc_pagecache(int fd, size_t size)
369 if (ftruncate(fd, size))
372 for (i = 0; i < size; i += sizeof(buf))
373 read(fd, buf, sizeof(buf));
381 int alloc_anon(const char *cgroup, void *arg)
383 size_t size = (unsigned long)arg;
387 for (ptr = buf; ptr < buf + size; ptr += PAGE_SIZE)
394 int is_swap_enabled(void)
397 const char delim[] = "\n";
401 if (read_text("/proc/swaps", buf, sizeof(buf)) <= 0)
404 for (line = strtok(buf, delim); line; line = strtok(NULL, delim))
410 int set_oom_adj_score(int pid, int score)
415 sprintf(path, "/proc/%d/oom_score_adj", pid);
417 fd = open(path, O_WRONLY | O_APPEND);
421 len = dprintf(fd, "%d", score);
431 ssize_t proc_read_text(int pid, bool thread, const char *item, char *buf, size_t size)
436 snprintf(path, sizeof(path), "/proc/%s/%s",
437 thread ? "thread-self" : "self", item);
439 snprintf(path, sizeof(path), "/proc/%d/%s", pid, item);
441 return read_text(path, buf, size);
444 int proc_read_strstr(int pid, bool thread, const char *item, const char *needle)
448 if (proc_read_text(pid, thread, item, buf, sizeof(buf)) < 0)
451 return strstr(buf, needle) ? 0 : -1;