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,
92 size_t size = strlen(expected) + 1;
99 if (cg_read(cgroup, control, buf, size))
102 return strcmp(expected, buf);
105 int cg_read_strstr(const char *cgroup, const char *control, const char *needle)
109 if (cg_read(cgroup, control, buf, sizeof(buf)))
112 return strstr(buf, needle) ? 0 : -1;
115 long cg_read_long(const char *cgroup, const char *control)
119 if (cg_read(cgroup, control, buf, sizeof(buf)))
125 long cg_read_key_long(const char *cgroup, const char *control, const char *key)
130 if (cg_read(cgroup, control, buf, sizeof(buf)))
133 ptr = strstr(buf, key);
137 return atol(ptr + strlen(key));
140 int cg_write(const char *cgroup, const char *control, char *buf)
143 ssize_t len = strlen(buf);
145 snprintf(path, sizeof(path), "%s/%s", cgroup, control);
147 if (write_text(path, buf, len) == len)
153 int cg_find_unified_root(char *root, size_t len)
155 char buf[10 * PAGE_SIZE];
156 char *fs, *mount, *type;
157 const char delim[] = "\n\t ";
159 if (read_text("/proc/self/mounts", buf, sizeof(buf)) <= 0)
164 * cgroup /sys/fs/cgroup cgroup2 rw,seclabel,noexec,relatime 0 0
166 for (fs = strtok(buf, delim); fs; fs = strtok(NULL, delim)) {
167 mount = strtok(NULL, delim);
168 type = strtok(NULL, delim);
173 if (strcmp(fs, "cgroup") == 0 &&
174 strcmp(type, "cgroup2") == 0) {
175 strncpy(root, mount, len);
183 int cg_create(const char *cgroup)
185 return mkdir(cgroup, 0644);
188 static int cg_killall(const char *cgroup)
193 if (cg_read(cgroup, "cgroup.procs", buf, sizeof(buf)))
196 while (ptr < buf + sizeof(buf)) {
197 int pid = strtol(ptr, &ptr, 10);
205 if (kill(pid, SIGKILL))
212 int cg_destroy(const char *cgroup)
218 if (ret && errno == EBUSY) {
219 ret = cg_killall(cgroup);
226 if (ret && errno == ENOENT)
232 int cg_enter_current(const char *cgroup)
236 snprintf(pidbuf, sizeof(pidbuf), "%d", getpid());
237 return cg_write(cgroup, "cgroup.procs", pidbuf);
240 int cg_run(const char *cgroup,
241 int (*fn)(const char *cgroup, void *arg),
249 } else if (pid == 0) {
252 snprintf(buf, sizeof(buf), "%d", getpid());
253 if (cg_write(cgroup, "cgroup.procs", buf))
255 exit(fn(cgroup, arg));
257 waitpid(pid, &retcode, 0);
258 if (WIFEXITED(retcode))
259 return WEXITSTATUS(retcode);
265 int cg_run_nowait(const char *cgroup,
266 int (*fn)(const char *cgroup, void *arg),
275 snprintf(buf, sizeof(buf), "%d", getpid());
276 if (cg_write(cgroup, "cgroup.procs", buf))
278 exit(fn(cgroup, arg));
284 int get_temp_fd(void)
286 return open(".", O_TMPFILE | O_RDWR | O_EXCL);
289 int alloc_pagecache(int fd, size_t size)
300 if (ftruncate(fd, size))
303 for (i = 0; i < size; i += sizeof(buf))
304 read(fd, buf, sizeof(buf));
312 int alloc_anon(const char *cgroup, void *arg)
314 size_t size = (unsigned long)arg;
318 for (ptr = buf; ptr < buf + size; ptr += PAGE_SIZE)
325 int is_swap_enabled(void)
328 const char delim[] = "\n";
332 if (read_text("/proc/swaps", buf, sizeof(buf)) <= 0)
335 for (line = strtok(buf, delim); line; line = strtok(NULL, delim))