/*
* called during cgroup.c:cgroup_ops_init(), at startup. No threads.
* We check whether we can talk to cgmanager, escape to root cgroup if
* we are root, then close the connection.
*/
struct cgroup_ops *cgm_ops_init(void)
{
check_supports_multiple_controllers(-1);
if (!collect_subsytems())
return NULL;
if (api_version < CGM_SUPPORTS_MULT_CONTROLLERS)
cgm_supports_multiple_controllers = false;
// if root, try to escape to root cgroup
if (geteuid() == 0 && !cgm_escape()) {
free_subsystems();
return NULL;
}
return &cgmanager_ops;
}
/*
* called during cgroup.c:cgroup_ops_init(), at startup. No threads.
* We check whether we can talk to cgmanager, escape to root cgroup if
* we are root, then close the connection.
*/
struct cgroup_ops *cgm_ops_init(void)
{
if (!collect_subsytems())
return NULL;
if (!cgm_dbus_connect())
goto err1;
// root; try to escape to root cgroup
if (geteuid() == 0 && !lxc_cgmanager_escape())
goto err2;
cgm_dbus_disconnect();
return &cgmanager_ops;
err2:
cgm_dbus_disconnect();
err1:
free_subsystems();
return NULL;
}
static bool collect_subsytems(void)
{
char *line = NULL;
nih_local char **cgm_subsys_list = NULL;
size_t sz = 0;
FILE *f = NULL;
if (subsystems) // already initialized
return true;
subsystems_inone = malloc(2 * sizeof(char *));
if (!subsystems_inone)
return false;
subsystems_inone[0] = "all";
subsystems_inone[1] = NULL;
if (lxc_list_controllers(&cgm_subsys_list)) {
while (cgm_subsys_list[nr_subsystems]) {
char **tmp = NIH_MUST( realloc(subsystems,
(nr_subsystems+2)*sizeof(char *)) );
tmp[nr_subsystems] = NIH_MUST(
strdup(cgm_subsys_list[nr_subsystems++]) );
subsystems = tmp;
}
if (nr_subsystems)
subsystems[nr_subsystems] = NULL;
goto collected;
}
INFO("cgmanager_list_controllers failed, falling back to /proc/self/cgroups");
f = fopen_cloexec("/proc/self/cgroup", "r");
if (!f) {
f = fopen_cloexec("/proc/1/cgroup", "r");
if (!f)
return false;
}
while (getline(&line, &sz, f) != -1) {
/* file format: hierarchy:subsystems:group,
* with multiple subsystems being ,-separated */
char *slist, *end, *p, *saveptr = NULL, **tmp;
if (!line[0])
continue;
slist = strchr(line, ':');
if (!slist)
continue;
slist++;
end = strchr(slist, ':');
if (!end)
continue;
*end = '\0';
for (p = strtok_r(slist, ",", &saveptr);
p;
p = strtok_r(NULL, ",", &saveptr)) {
tmp = realloc(subsystems, (nr_subsystems+2)*sizeof(char *));
if (!tmp)
goto out_free;
subsystems = tmp;
tmp[nr_subsystems] = strdup(p);
tmp[nr_subsystems+1] = NULL;
if (!tmp[nr_subsystems])
goto out_free;
nr_subsystems++;
}
}
fclose(f);
f = NULL;
free(line);
line = NULL;
collected:
if (!nr_subsystems) {
ERROR("No cgroup subsystems found");
return false;
}
/* make sure that cgroup.use can be and is honored */
const char *cgroup_use = lxc_global_config_value("lxc.cgroup.use");
if (!cgroup_use && errno != 0)
goto final_verify;
if (cgroup_use) {
if (!verify_and_prune(cgroup_use)) {
free_subsystems();
return false;
}
subsystems_inone[0] = NIH_MUST( strdup(cgroup_use) );
cgm_all_controllers_same = false;
}
final_verify:
return verify_final_subsystems(cgroup_use);
out_free:
free(line);
if (f)
fclose(f);
free_subsystems();
return false;
}
static bool collect_subsytems(void)
{
char *line = NULL;
size_t sz = 0;
FILE *f;
if (subsystems) // already initialized
return true;
subsystems_inone = malloc(2 * sizeof(char *));
if (!subsystems_inone)
return false;
subsystems_inone[0] = "all";
subsystems_inone[1] = NULL;
f = fopen_cloexec("/proc/self/cgroup", "r");
if (!f) {
f = fopen_cloexec("/proc/1/cgroup", "r");
if (!f)
return false;
}
while (getline(&line, &sz, f) != -1) {
/* file format: hierarchy:subsystems:group,
* with multiple subsystems being ,-separated */
char *slist, *end, *p, *saveptr = NULL, **tmp;
if (!line[0])
continue;
slist = strchr(line, ':');
if (!slist)
continue;
slist++;
end = strchr(slist, ':');
if (!end)
continue;
*end = '\0';
for (p = strtok_r(slist, ",", &saveptr);
p;
p = strtok_r(NULL, ",", &saveptr)) {
tmp = realloc(subsystems, (nr_subsystems+2)*sizeof(char *));
if (!tmp)
goto out_free;
subsystems = tmp;
tmp[nr_subsystems] = strdup(p);
tmp[nr_subsystems+1] = NULL;
if (!tmp[nr_subsystems])
goto out_free;
nr_subsystems++;
}
}
fclose(f);
free(line);
if (!nr_subsystems) {
ERROR("No cgroup subsystems found");
return false;
}
return true;
out_free:
free(line);
fclose(f);
free_subsystems();
return false;
}
