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pid1: add support for cgroup.kill

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This commit is contained in:
Albert Brox 2021-07-20 18:24:20 -04:00 committed by Lennart Poettering
parent 2846007ecf
commit 8a513eee30
2 changed files with 74 additions and 23 deletions
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95
src/basic/cgroup-util.c
View File

@ -160,6 +160,24 @@ bool cg_freezer_supported(void) {
return supported;
}
bool cg_kill_supported(void) {
static thread_local int supported = -1;
if (supported >= 0)
return supported;
if (cg_all_unified() <= 0)
supported = false;
else if (access("/sys/fs/cgroup/init.scope/cgroup.kill", F_OK) < 0) {
if (errno != ENOENT)
log_debug_errno(errno, "Failed to check if cgroup.kill is available, assuming not: %m");
supported = false;
} else
supported = true;
return supported;
}
int cg_enumerate_subgroups(const char *controller, const char *path, DIR **_d) {
_cleanup_free_ char *fs = NULL;
int r;
@ -358,6 +376,29 @@ int cg_kill(
return cg_kill_items(controller, path, sig, flags, s, log_kill, userdata, "cgroup.threads");
}
int cg_kill_kernel_sigkill(const char *controller, const char *path) {
/* Kills the cgroup at `path` directly by writing to its cgroup.kill file.
* This sends SIGKILL to all processes in the cgroup and has the advantage of
* being completely atomic, unlike cg_kill_items. */
int r;
_cleanup_free_ char *killfile = NULL;
assert(path);
if (!cg_kill_supported())
return -EOPNOTSUPP;
r = cg_get_path(controller, path, "cgroup.kill", &killfile);
if (r < 0)
return r;
r = write_string_file(killfile, "1", WRITE_STRING_FILE_DISABLE_BUFFER);
if (r < 0)
return r;
return 0;
}
int cg_kill_recursive(
const char *controller,
const char *path,
@ -375,38 +416,46 @@ int cg_kill_recursive(
assert(path);
assert(sig >= 0);
if (!s) {
s = allocated_set = set_new(NULL);
if (!s)
return -ENOMEM;
}
if (sig == SIGKILL && cg_kill_supported() &&
!FLAGS_SET(flags, CGROUP_IGNORE_SELF) && !s && !log_kill) {
/* ignore CGROUP_SIGCONT, since this is a no-op alongside SIGKILL */
ret = cg_kill_kernel_sigkill(controller, path);
if (ret < 0)
return ret;
} else {
if (!s) {
s = allocated_set = set_new(NULL);
if (!s)
return -ENOMEM;
}
ret = cg_kill(controller, path, sig, flags, s, log_kill, userdata);
ret = cg_kill(controller, path, sig, flags, s, log_kill, userdata);
r = cg_enumerate_subgroups(controller, path, &d);
if (r < 0) {
if (ret >= 0 && r != -ENOENT)
return r;
r = cg_enumerate_subgroups(controller, path, &d);
if (r < 0) {
if (ret >= 0 && r != -ENOENT)
return r;
return ret;
}
return ret;
}
while ((r = cg_read_subgroup(d, &fn)) > 0) {
_cleanup_free_ char *p = NULL;
while ((r = cg_read_subgroup(d, &fn)) > 0) {
_cleanup_free_ char *p = NULL;
p = path_join(empty_to_root(path), fn);
free(fn);
if (!p)
return -ENOMEM;
p = path_join(empty_to_root(path), fn);
free(fn);
if (!p)
return -ENOMEM;
r = cg_kill_recursive(controller, p, sig, flags, s, log_kill, userdata);
if (r != 0 && ret >= 0)
r = cg_kill_recursive(controller, p, sig, flags, s, log_kill, userdata);
if (r != 0 && ret >= 0)
ret = r;
}
if (ret >= 0 && r < 0)
ret = r;
}
if (ret >= 0 && r < 0)
ret = r;
if (flags & CGROUP_REMOVE) {
if (FLAGS_SET(flags, CGROUP_REMOVE)) {
r = cg_rmdir(controller, path);
if (r < 0 && ret >= 0 && !IN_SET(r, -ENOENT, -EBUSY))
return r;

2
src/basic/cgroup-util.h
View File

@ -172,6 +172,7 @@ typedef enum CGroupFlags {
typedef int (*cg_kill_log_func_t)(pid_t pid, int sig, void *userdata);
int cg_kill(const char *controller, const char *path, int sig, CGroupFlags flags, Set *s, cg_kill_log_func_t kill_log, void *userdata);
int cg_kill_kernel_sigkill(const char *controller, const char *path);
int cg_kill_recursive(const char *controller, const char *path, int sig, CGroupFlags flags, Set *s, cg_kill_log_func_t kill_log, void *userdata);
int cg_split_spec(const char *spec, char **ret_controller, char **ret_path);
@ -272,6 +273,7 @@ int cg_kernel_controllers(Set **controllers);
bool cg_ns_supported(void);
bool cg_freezer_supported(void);
bool cg_kill_supported(void);
int cg_all_unified(void);
int cg_hybrid_unified(void);