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Systemd/src/core/cgroup.c

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/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
/***
This file is part of systemd.
Copyright 2013 Lennart Poettering
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include <fcntl.h>
#include <fnmatch.h>
#include "path-util.h"
#include "special.h"
#include "cgroup-util.h"
#include "cgroup.h"
#define CGROUP_CPU_QUOTA_PERIOD_USEC ((usec_t) 100 * USEC_PER_MSEC)
void cgroup_context_init(CGroupContext *c) {
assert(c);
/* Initialize everything to the kernel defaults, assuming the
* structure is preinitialized to 0 */
c->cpu_shares = (unsigned long) -1;
c->startup_cpu_shares = (unsigned long) -1;
c->memory_limit = (uint64_t) -1;
c->blockio_weight = (unsigned long) -1;
c->startup_blockio_weight = (unsigned long) -1;
c->cpu_quota_per_sec_usec = USEC_INFINITY;
}
void cgroup_context_free_device_allow(CGroupContext *c, CGroupDeviceAllow *a) {
assert(c);
assert(a);
LIST_REMOVE(device_allow, c->device_allow, a);
free(a->path);
free(a);
}
void cgroup_context_free_blockio_device_weight(CGroupContext *c, CGroupBlockIODeviceWeight *w) {
assert(c);
assert(w);
LIST_REMOVE(device_weights, c->blockio_device_weights, w);
free(w->path);
free(w);
}
void cgroup_context_free_blockio_device_bandwidth(CGroupContext *c, CGroupBlockIODeviceBandwidth *b) {
assert(c);
assert(b);
LIST_REMOVE(device_bandwidths, c->blockio_device_bandwidths, b);
free(b->path);
free(b);
}
void cgroup_context_done(CGroupContext *c) {
assert(c);
while (c->blockio_device_weights)
cgroup_context_free_blockio_device_weight(c, c->blockio_device_weights);
while (c->blockio_device_bandwidths)
cgroup_context_free_blockio_device_bandwidth(c, c->blockio_device_bandwidths);
while (c->device_allow)
cgroup_context_free_device_allow(c, c->device_allow);
}
void cgroup_context_dump(CGroupContext *c, FILE* f, const char *prefix) {
CGroupBlockIODeviceBandwidth *b;
CGroupBlockIODeviceWeight *w;
CGroupDeviceAllow *a;
char u[FORMAT_TIMESPAN_MAX];
assert(c);
assert(f);
prefix = strempty(prefix);
fprintf(f,
"%sCPUAccounting=%s\n"
"%sBlockIOAccounting=%s\n"
"%sMemoryAccounting=%s\n"
"%sCPUShares=%lu\n"
"%sStartupCPUShares=%lu\n"
"%sCPUQuotaPerSecSec=%s\n"
"%sBlockIOWeight=%lu\n"
"%sStartupBlockIOWeight=%lu\n"
"%sMemoryLimit=%" PRIu64 "\n"
"%sDevicePolicy=%s\n"
"%sDelegate=%s\n",
prefix, yes_no(c->cpu_accounting),
prefix, yes_no(c->blockio_accounting),
prefix, yes_no(c->memory_accounting),
prefix, c->cpu_shares,
prefix, c->startup_cpu_shares,
prefix, format_timespan(u, sizeof(u), c->cpu_quota_per_sec_usec, 1),
prefix, c->blockio_weight,
prefix, c->startup_blockio_weight,
prefix, c->memory_limit,
prefix, cgroup_device_policy_to_string(c->device_policy),
prefix, yes_no(c->delegate));
LIST_FOREACH(device_allow, a, c->device_allow)
fprintf(f,
"%sDeviceAllow=%s %s%s%s\n",
prefix,
a->path,
a->r ? "r" : "", a->w ? "w" : "", a->m ? "m" : "");
LIST_FOREACH(device_weights, w, c->blockio_device_weights)
fprintf(f,
"%sBlockIODeviceWeight=%s %lu",
prefix,
w->path,
w->weight);
LIST_FOREACH(device_bandwidths, b, c->blockio_device_bandwidths) {
char buf[FORMAT_BYTES_MAX];
fprintf(f,
"%s%s=%s %s\n",
prefix,
b->read ? "BlockIOReadBandwidth" : "BlockIOWriteBandwidth",
b->path,
format_bytes(buf, sizeof(buf), b->bandwidth));
}
}
static int lookup_blkio_device(const char *p, dev_t *dev) {
struct stat st;
int r;
assert(p);
assert(dev);
r = stat(p, &st);
if (r < 0)
return log_warning_errno(errno, "Couldn't stat device %s: %m", p);
if (S_ISBLK(st.st_mode))
*dev = st.st_rdev;
else if (major(st.st_dev) != 0) {
/* If this is not a device node then find the block
* device this file is stored on */
*dev = st.st_dev;
/* If this is a partition, try to get the originating
* block device */
block_get_whole_disk(*dev, dev);
} else {
log_warning("%s is not a block device and file system block device cannot be determined or is not local.", p);
return -ENODEV;
}
return 0;
}
static int whitelist_device(const char *path, const char *node, const char *acc) {
char buf[2+DECIMAL_STR_MAX(dev_t)*2+2+4];
struct stat st;
int r;
assert(path);
assert(acc);
if (stat(node, &st) < 0) {
log_warning("Couldn't stat device %s", node);
return -errno;
}
if (!S_ISCHR(st.st_mode) && !S_ISBLK(st.st_mode)) {
log_warning("%s is not a device.", node);
return -ENODEV;
}
sprintf(buf,
"%c %u:%u %s",
S_ISCHR(st.st_mode) ? 'c' : 'b',
major(st.st_rdev), minor(st.st_rdev),
acc);
r = cg_set_attribute("devices", path, "devices.allow", buf);
if (r < 0)
log_full_errno(IN_SET(r, -ENOENT, -EROFS, -EINVAL) ? LOG_DEBUG : LOG_WARNING, r,
"Failed to set devices.allow on %s: %m", path);
return r;
}
static int whitelist_major(const char *path, const char *name, char type, const char *acc) {
_cleanup_fclose_ FILE *f = NULL;
char line[LINE_MAX];
bool good = false;
int r;
assert(path);
assert(acc);
assert(type == 'b' || type == 'c');
f = fopen("/proc/devices", "re");
if (!f)
return log_warning_errno(errno, "Cannot open /proc/devices to resolve %s (%c): %m", name, type);
FOREACH_LINE(line, f, goto fail) {
char buf[2+DECIMAL_STR_MAX(unsigned)+3+4], *p, *w;
unsigned maj;
truncate_nl(line);
if (type == 'c' && streq(line, "Character devices:")) {
good = true;
continue;
}
if (type == 'b' && streq(line, "Block devices:")) {
good = true;
continue;
}
if (isempty(line)) {
good = false;
continue;
}
if (!good)
continue;
p = strstrip(line);
w = strpbrk(p, WHITESPACE);
if (!w)
continue;
*w = 0;
r = safe_atou(p, &maj);
if (r < 0)
continue;
if (maj <= 0)
continue;
w++;
w += strspn(w, WHITESPACE);
if (fnmatch(name, w, 0) != 0)
continue;
sprintf(buf,
"%c %u:* %s",
type,
maj,
acc);
r = cg_set_attribute("devices", path, "devices.allow", buf);
if (r < 0)
log_full_errno(IN_SET(r, -ENOENT, -EROFS, -EINVAL) ? LOG_DEBUG : LOG_WARNING, r,
"Failed to set devices.allow on %s: %m", path);
}
return 0;
fail:
log_warning_errno(errno, "Failed to read /proc/devices: %m");
return -errno;
}
void cgroup_context_apply(CGroupContext *c, CGroupControllerMask mask, const char *path, ManagerState state) {
bool is_root;
int r;
assert(c);
assert(path);
if (mask == 0)
return;
/* Some cgroup attributes are not supported on the root cgroup,
* hence silently ignore */
is_root = isempty(path) || path_equal(path, "/");
if (is_root)
/* Make sure we don't try to display messages with an empty path. */
path = "/";
/* We generally ignore errors caused by read-only mounted
* cgroup trees (assuming we are running in a container then),
* and missing cgroups, i.e. EROFS and ENOENT. */
if ((mask & CGROUP_CPU) && !is_root) {
char buf[MAX(DECIMAL_STR_MAX(unsigned long), DECIMAL_STR_MAX(usec_t)) + 1];
sprintf(buf, "%lu\n",
IN_SET(state, MANAGER_STARTING, MANAGER_INITIALIZING) && c->startup_cpu_shares != (unsigned long) -1 ? c->startup_cpu_shares :
c->cpu_shares != (unsigned long) -1 ? c->cpu_shares : 1024);
r = cg_set_attribute("cpu", path, "cpu.shares", buf);
if (r < 0)
log_full_errno(IN_SET(r, -ENOENT, -EROFS) ? LOG_DEBUG : LOG_WARNING, r,
"Failed to set cpu.shares on %s: %m", path);
sprintf(buf, USEC_FMT "\n", CGROUP_CPU_QUOTA_PERIOD_USEC);
r = cg_set_attribute("cpu", path, "cpu.cfs_period_us", buf);
if (r < 0)
log_full_errno(IN_SET(r, -ENOENT, -EROFS) ? LOG_DEBUG : LOG_WARNING, r,
"Failed to set cpu.cfs_period_us on %s: %m", path);
if (c->cpu_quota_per_sec_usec != USEC_INFINITY) {
sprintf(buf, USEC_FMT "\n", c->cpu_quota_per_sec_usec * CGROUP_CPU_QUOTA_PERIOD_USEC / USEC_PER_SEC);
r = cg_set_attribute("cpu", path, "cpu.cfs_quota_us", buf);
} else
r = cg_set_attribute("cpu", path, "cpu.cfs_quota_us", "-1");
if (r < 0)
log_full_errno(IN_SET(r, -ENOENT, -EROFS) ? LOG_DEBUG : LOG_WARNING, r,
"Failed to set cpu.cfs_quota_us on %s: %m", path);
}
if (mask & CGROUP_BLKIO) {
char buf[MAX3(DECIMAL_STR_MAX(unsigned long)+1,
DECIMAL_STR_MAX(dev_t)*2+2+DECIMAL_STR_MAX(unsigned long)*1,
DECIMAL_STR_MAX(dev_t)*2+2+DECIMAL_STR_MAX(uint64_t)+1)];
CGroupBlockIODeviceWeight *w;
CGroupBlockIODeviceBandwidth *b;
if (!is_root) {
sprintf(buf, "%lu\n", IN_SET(state, MANAGER_STARTING, MANAGER_INITIALIZING) && c->startup_blockio_weight != (unsigned long) -1 ? c->startup_blockio_weight :
c->blockio_weight != (unsigned long) -1 ? c->blockio_weight : 1000);
r = cg_set_attribute("blkio", path, "blkio.weight", buf);
if (r < 0)
log_full_errno(IN_SET(r, -ENOENT, -EROFS) ? LOG_DEBUG : LOG_WARNING, r,
"Failed to set blkio.weight on %s: %m", path);
/* FIXME: no way to reset this list */
LIST_FOREACH(device_weights, w, c->blockio_device_weights) {
dev_t dev;
r = lookup_blkio_device(w->path, &dev);
if (r < 0)
continue;
sprintf(buf, "%u:%u %lu", major(dev), minor(dev), w->weight);
r = cg_set_attribute("blkio", path, "blkio.weight_device", buf);
if (r < 0)
log_full_errno(IN_SET(r, -ENOENT, -EROFS) ? LOG_DEBUG : LOG_WARNING, r,
"Failed to set blkio.weight_device on %s: %m", path);
}
}
/* FIXME: no way to reset this list */
LIST_FOREACH(device_bandwidths, b, c->blockio_device_bandwidths) {
const char *a;
dev_t dev;
r = lookup_blkio_device(b->path, &dev);
if (r < 0)
continue;
a = b->read ? "blkio.throttle.read_bps_device" : "blkio.throttle.write_bps_device";
sprintf(buf, "%u:%u %" PRIu64 "\n", major(dev), minor(dev), b->bandwidth);
r = cg_set_attribute("blkio", path, a, buf);
if (r < 0)
log_full_errno(IN_SET(r, -ENOENT, -EROFS) ? LOG_DEBUG : LOG_WARNING, r,
"Failed to set %s on %s: %m", a, path);
}
}
if ((mask & CGROUP_MEMORY) & !is_root) {
if (c->memory_limit != (uint64_t) -1) {
char buf[DECIMAL_STR_MAX(uint64_t) + 1];
sprintf(buf, "%" PRIu64 "\n", c->memory_limit);
r = cg_set_attribute("memory", path, "memory.limit_in_bytes", buf);
} else
r = cg_set_attribute("memory", path, "memory.limit_in_bytes", "-1");
if (r < 0)
log_full_errno(IN_SET(r, -ENOENT, -EROFS) ? LOG_DEBUG : LOG_WARNING, r,
"Failed to set memory.limit_in_bytes on %s: %m", path);
}
if ((mask & CGROUP_DEVICE) && !is_root) {
CGroupDeviceAllow *a;
/* Changing the devices list of a populated cgroup
* might result in EINVAL, hence ignore EINVAL
* here. */
if (c->device_allow || c->device_policy != CGROUP_AUTO)
r = cg_set_attribute("devices", path, "devices.deny", "a");
else
r = cg_set_attribute("devices", path, "devices.allow", "a");
if (r < 0)
log_full_errno(IN_SET(r, -ENOENT, -EROFS, -EINVAL) ? LOG_DEBUG : LOG_WARNING, r,
"Failed to reset devices.list on %s: %m", path);
if (c->device_policy == CGROUP_CLOSED ||
(c->device_policy == CGROUP_AUTO && c->device_allow)) {
static const char auto_devices[] =
"/dev/null\0" "rwm\0"
"/dev/zero\0" "rwm\0"
"/dev/full\0" "rwm\0"
"/dev/random\0" "rwm\0"
"/dev/urandom\0" "rwm\0"
"/dev/tty\0" "rwm\0"
"/dev/pts/ptmx\0" "rw\0"; /* /dev/pts/ptmx may not be duplicated, but accessed */
const char *x, *y;
NULSTR_FOREACH_PAIR(x, y, auto_devices)
whitelist_device(path, x, y);
whitelist_major(path, "pts", 'c', "rw");
whitelist_major(path, "kdbus", 'c', "rw");
whitelist_major(path, "kdbus/*", 'c', "rw");
}
LIST_FOREACH(device_allow, a, c->device_allow) {
char acc[4];
unsigned k = 0;
if (a->r)
acc[k++] = 'r';
if (a->w)
acc[k++] = 'w';
if (a->m)
acc[k++] = 'm';
if (k == 0)
continue;
acc[k++] = 0;
if (startswith(a->path, "/dev/"))
whitelist_device(path, a->path, acc);
else if (startswith(a->path, "block-"))
whitelist_major(path, a->path + 6, 'b', acc);
else if (startswith(a->path, "char-"))
whitelist_major(path, a->path + 5, 'c', acc);
else
log_debug("Ignoring device %s while writing cgroup attribute.", a->path);
}
}
}
CGroupControllerMask cgroup_context_get_mask(CGroupContext *c) {
CGroupControllerMask mask = 0;
/* Figure out which controllers we need */
if (c->cpu_accounting ||
c->cpu_shares != (unsigned long) -1 ||
c->startup_cpu_shares != (unsigned long) -1 ||
c->cpu_quota_per_sec_usec != USEC_INFINITY)
mask |= CGROUP_CPUACCT | CGROUP_CPU;
if (c->blockio_accounting ||
c->blockio_weight != (unsigned long) -1 ||
c->startup_blockio_weight != (unsigned long) -1 ||
c->blockio_device_weights ||
c->blockio_device_bandwidths)
mask |= CGROUP_BLKIO;
if (c->memory_accounting ||
c->memory_limit != (uint64_t) -1)
mask |= CGROUP_MEMORY;
if (c->device_allow ||
c->device_policy != CGROUP_AUTO)
mask |= CGROUP_DEVICE;
return mask;
}
CGroupControllerMask unit_get_cgroup_mask(Unit *u) {
CGroupContext *c;
c = unit_get_cgroup_context(u);
if (!c)
return 0;
/* If delegation is turned on, then turn on all cgroups,
* unless the process we fork into it is known to drop
* privileges anyway, and shouldn't get access to the
* controllers anyway. */
if (c->delegate) {
ExecContext *e;
e = unit_get_exec_context(u);
if (!e || exec_context_maintains_privileges(e))
return _CGROUP_CONTROLLER_MASK_ALL;
}
return cgroup_context_get_mask(c);
}
CGroupControllerMask unit_get_members_mask(Unit *u) {
assert(u);
if (u->cgroup_members_mask_valid)
return u->cgroup_members_mask;
u->cgroup_members_mask = 0;
if (u->type == UNIT_SLICE) {
Unit *member;
Iterator i;
SET_FOREACH(member, u->dependencies[UNIT_BEFORE], i) {
if (member == u)
continue;
if (UNIT_DEREF(member->slice) != u)
continue;
u->cgroup_members_mask |=
unit_get_cgroup_mask(member) |
unit_get_members_mask(member);
}
}
u->cgroup_members_mask_valid = true;
return u->cgroup_members_mask;
}
CGroupControllerMask unit_get_siblings_mask(Unit *u) {
assert(u);
if (UNIT_ISSET(u->slice))
return unit_get_members_mask(UNIT_DEREF(u->slice));
return unit_get_cgroup_mask(u) | unit_get_members_mask(u);
}
CGroupControllerMask unit_get_target_mask(Unit *u) {
CGroupControllerMask mask;
mask = unit_get_cgroup_mask(u) | unit_get_members_mask(u) | unit_get_siblings_mask(u);
mask &= u->manager->cgroup_supported;
return mask;
}
/* Recurse from a unit up through its containing slices, propagating
* mask bits upward. A unit is also member of itself. */
void unit_update_cgroup_members_masks(Unit *u) {
CGroupControllerMask m;
bool more;
assert(u);
/* Calculate subtree mask */
m = unit_get_cgroup_mask(u) | unit_get_members_mask(u);
/* See if anything changed from the previous invocation. If
* not, we're done. */
if (u->cgroup_subtree_mask_valid && m == u->cgroup_subtree_mask)
return;
more =
u->cgroup_subtree_mask_valid &&
((m & ~u->cgroup_subtree_mask) != 0) &&
((~m & u->cgroup_subtree_mask) == 0);
u->cgroup_subtree_mask = m;
u->cgroup_subtree_mask_valid = true;
if (UNIT_ISSET(u->slice)) {
Unit *s = UNIT_DEREF(u->slice);
if (more)
/* There's more set now than before. We
* propagate the new mask to the parent's mask
* (not caring if it actually was valid or
* not). */
s->cgroup_members_mask |= m;
else
/* There's less set now than before (or we
* don't know), we need to recalculate
* everything, so let's invalidate the
* parent's members mask */
s->cgroup_members_mask_valid = false;
/* And now make sure that this change also hits our
* grandparents */
unit_update_cgroup_members_masks(s);
}
}
static const char *migrate_callback(CGroupControllerMask mask, void *userdata) {
Unit *u = userdata;
assert(mask != 0);
assert(u);
while (u) {
if (u->cgroup_path &&
u->cgroup_realized &&
(u->cgroup_realized_mask & mask) == mask)
return u->cgroup_path;
u = UNIT_DEREF(u->slice);
}
return NULL;
}
static int unit_create_cgroups(Unit *u, CGroupControllerMask mask) {
CGroupContext *c;
int r;
assert(u);
c = unit_get_cgroup_context(u);
if (!c)
return 0;
if (!u->cgroup_path) {
_cleanup_free_ char *path = NULL;
path = unit_default_cgroup_path(u);
if (!path)
return log_oom();
r = hashmap_put(u->manager->cgroup_unit, path, u);
if (r < 0) {
log_error(r == -EEXIST ? "cgroup %s exists already: %s" : "hashmap_put failed for %s: %s", path, strerror(-r));
return r;
}
if (r > 0) {
u->cgroup_path = path;
path = NULL;
}
}
/* First, create our own group */
r = cg_create_everywhere(u->manager->cgroup_supported, mask, u->cgroup_path);
if (r < 0)
return log_error_errno(r, "Failed to create cgroup %s: %m", u->cgroup_path);
/* Keep track that this is now realized */
u->cgroup_realized = true;
u->cgroup_realized_mask = mask;
if (u->type != UNIT_SLICE && !c->delegate) {
/* Then, possibly move things over, but not if
* subgroups may contain processes, which is the case
* for slice and delegation units. */
r = cg_migrate_everywhere(u->manager->cgroup_supported, u->cgroup_path, u->cgroup_path, migrate_callback, u);
if (r < 0)
log_warning_errno(r, "Failed to migrate cgroup from to %s: %m", u->cgroup_path);
}
return 0;
}
int unit_attach_pids_to_cgroup(Unit *u) {
int r;
assert(u);
r = unit_realize_cgroup(u);
if (r < 0)
return r;
r = cg_attach_many_everywhere(u->manager->cgroup_supported, u->cgroup_path, u->pids, migrate_callback, u);
if (r < 0)
return r;
return 0;
}
static bool unit_has_mask_realized(Unit *u, CGroupControllerMask mask) {
assert(u);
return u->cgroup_realized && u->cgroup_realized_mask == mask;
}
/* Check if necessary controllers and attributes for a unit are in place.
*
* If so, do nothing.
* If not, create paths, move processes over, and set attributes.
*
* Returns 0 on success and < 0 on failure. */
static int unit_realize_cgroup_now(Unit *u, ManagerState state) {
CGroupControllerMask mask;
int r;
assert(u);
if (u->in_cgroup_queue) {
LIST_REMOVE(cgroup_queue, u->manager->cgroup_queue, u);
u->in_cgroup_queue = false;
}
mask = unit_get_target_mask(u);
if (unit_has_mask_realized(u, mask))
return 0;
/* First, realize parents */
if (UNIT_ISSET(u->slice)) {
r = unit_realize_cgroup_now(UNIT_DEREF(u->slice), state);
if (r < 0)
return r;
}
/* And then do the real work */
r = unit_create_cgroups(u, mask);
if (r < 0)
return r;
/* Finally, apply the necessary attributes. */
cgroup_context_apply(unit_get_cgroup_context(u), mask, u->cgroup_path, state);
return 0;
}
static void unit_add_to_cgroup_queue(Unit *u) {
if (u->in_cgroup_queue)
return;
LIST_PREPEND(cgroup_queue, u->manager->cgroup_queue, u);
u->in_cgroup_queue = true;
}
unsigned manager_dispatch_cgroup_queue(Manager *m) {
ManagerState state;
unsigned n = 0;
Unit *i;
int r;
state = manager_state(m);
while ((i = m->cgroup_queue)) {
assert(i->in_cgroup_queue);
r = unit_realize_cgroup_now(i, state);
if (r < 0)
log_warning_errno(r, "Failed to realize cgroups for queued unit %s: %m", i->id);
n++;
}
return n;
}
static void unit_queue_siblings(Unit *u) {
Unit *slice;
/* This adds the siblings of the specified unit and the
* siblings of all parent units to the cgroup queue. (But
* neither the specified unit itself nor the parents.) */
while ((slice = UNIT_DEREF(u->slice))) {
Iterator i;
Unit *m;
SET_FOREACH(m, slice->dependencies[UNIT_BEFORE], i) {
if (m == u)
continue;
/* Skip units that have a dependency on the slice
* but aren't actually in it. */
if (UNIT_DEREF(m->slice) != slice)
continue;
/* No point in doing cgroup application for units
* without active processes. */
if (UNIT_IS_INACTIVE_OR_FAILED(unit_active_state(m)))
continue;
/* If the unit doesn't need any new controllers
* and has current ones realized, it doesn't need
* any changes. */
if (unit_has_mask_realized(m, unit_get_target_mask(m)))
continue;
unit_add_to_cgroup_queue(m);
}
u = slice;
}
}
int unit_realize_cgroup(Unit *u) {
CGroupContext *c;
assert(u);
c = unit_get_cgroup_context(u);
if (!c)
return 0;
/* So, here's the deal: when realizing the cgroups for this
* unit, we need to first create all parents, but there's more
* actually: for the weight-based controllers we also need to
* make sure that all our siblings (i.e. units that are in the
* same slice as we are) have cgroups, too. Otherwise, things
* would become very uneven as each of their processes would
* get as much resources as all our group together. This call
* will synchronously create the parent cgroups, but will
* defer work on the siblings to the next event loop
* iteration. */
/* Add all sibling slices to the cgroup queue. */
unit_queue_siblings(u);
/* And realize this one now (and apply the values) */
return unit_realize_cgroup_now(u, manager_state(u->manager));
}
void unit_destroy_cgroup_if_empty(Unit *u) {
int r;
assert(u);
if (!u->cgroup_path)
return;
r = cg_trim_everywhere(u->manager->cgroup_supported, u->cgroup_path, !unit_has_name(u, SPECIAL_ROOT_SLICE));
if (r < 0) {
log_debug_errno(r, "Failed to destroy cgroup %s: %m", u->cgroup_path);
return;
}
hashmap_remove(u->manager->cgroup_unit, u->cgroup_path);
free(u->cgroup_path);
u->cgroup_path = NULL;
u->cgroup_realized = false;
u->cgroup_realized_mask = 0;
}
pid_t unit_search_main_pid(Unit *u) {
_cleanup_fclose_ FILE *f = NULL;
pid_t pid = 0, npid, mypid;
assert(u);
if (!u->cgroup_path)
return 0;
if (cg_enumerate_processes(SYSTEMD_CGROUP_CONTROLLER, u->cgroup_path, &f) < 0)
return 0;
mypid = getpid();
while (cg_read_pid(f, &npid) > 0) {
pid_t ppid;
if (npid == pid)
continue;
/* Ignore processes that aren't our kids */
if (get_parent_of_pid(npid, &ppid) >= 0 && ppid != mypid)
continue;
if (pid != 0) {
/* Dang, there's more than one daemonized PID
in this group, so we don't know what process
is the main process. */
pid = 0;
break;
}
pid = npid;
}
return pid;
}
int manager_setup_cgroup(Manager *m) {
_cleanup_free_ char *path = NULL;
int r;
assert(m);
/* 1. Determine hierarchy */
free(m->cgroup_root);
m->cgroup_root = NULL;
r = cg_pid_get_path(SYSTEMD_CGROUP_CONTROLLER, 0, &m->cgroup_root);
if (r < 0)
return log_error_errno(r, "Cannot determine cgroup we are running in: %m");
/* LEGACY: Already in /system.slice? If so, let's cut this
* off. This is to support live upgrades from older systemd
* versions where PID 1 was moved there. */
if (m->running_as == SYSTEMD_SYSTEM) {
char *e;
e = endswith(m->cgroup_root, "/" SPECIAL_SYSTEM_SLICE);
if (!e)
e = endswith(m->cgroup_root, "/system");
if (e)
*e = 0;
}
/* And make sure to store away the root value without trailing
* slash, even for the root dir, so that we can easily prepend
* it everywhere. */
if (streq(m->cgroup_root, "/"))
m->cgroup_root[0] = 0;
/* 2. Show data */
r = cg_get_path(SYSTEMD_CGROUP_CONTROLLER, m->cgroup_root, NULL, &path);
if (r < 0)
return log_error_errno(r, "Cannot find cgroup mount point: %m");
log_debug("Using cgroup controller " SYSTEMD_CGROUP_CONTROLLER ". File system hierarchy is at %s.", path);
if (!m->test_run) {
/* 3. Install agent */
if (m->running_as == SYSTEMD_SYSTEM) {
r = cg_install_release_agent(SYSTEMD_CGROUP_CONTROLLER, SYSTEMD_CGROUP_AGENT_PATH);
if (r < 0)
log_warning_errno(r, "Failed to install release agent, ignoring: %m");
else if (r > 0)
log_debug("Installed release agent.");
else
log_debug("Release agent already installed.");
}
/* 4. Make sure we are in the root cgroup */
r = cg_create_and_attach(SYSTEMD_CGROUP_CONTROLLER, m->cgroup_root, 0);
if (r < 0)
return log_error_errno(r, "Failed to create root cgroup hierarchy: %m");
/* 5. And pin it, so that it cannot be unmounted */
safe_close(m->pin_cgroupfs_fd);
m->pin_cgroupfs_fd = open(path, O_RDONLY|O_CLOEXEC|O_DIRECTORY|O_NOCTTY|O_NONBLOCK);
if (m->pin_cgroupfs_fd < 0)
return log_error_errno(errno, "Failed to open pin file: %m");
/* 6. Always enable hierarchical support if it exists... */
cg_set_attribute("memory", "/", "memory.use_hierarchy", "1");
}
/* 7. Figure out which controllers are supported */
m->cgroup_supported = cg_mask_supported();
return 0;
}
void manager_shutdown_cgroup(Manager *m, bool delete) {
assert(m);
/* We can't really delete the group, since we are in it. But
* let's trim it. */
if (delete && m->cgroup_root)
cg_trim(SYSTEMD_CGROUP_CONTROLLER, m->cgroup_root, false);
m->pin_cgroupfs_fd = safe_close(m->pin_cgroupfs_fd);
free(m->cgroup_root);
m->cgroup_root = NULL;
}
Unit* manager_get_unit_by_cgroup(Manager *m, const char *cgroup) {
char *p;
Unit *u;
assert(m);
assert(cgroup);
u = hashmap_get(m->cgroup_unit, cgroup);
if (u)
return u;
p = strdupa(cgroup);
for (;;) {
char *e;
e = strrchr(p, '/');
if (e == p || !e)
return NULL;
*e = 0;
u = hashmap_get(m->cgroup_unit, p);
if (u)
return u;
}
}
Unit *manager_get_unit_by_pid(Manager *m, pid_t pid) {
_cleanup_free_ char *cgroup = NULL;
int r;
assert(m);
if (pid <= 1)
return NULL;
r = cg_pid_get_path(SYSTEMD_CGROUP_CONTROLLER, pid, &cgroup);
if (r < 0)
return NULL;
return manager_get_unit_by_cgroup(m, cgroup);
}
int manager_notify_cgroup_empty(Manager *m, const char *cgroup) {
Unit *u;
int r;
assert(m);
assert(cgroup);
u = manager_get_unit_by_cgroup(m, cgroup);
if (u) {
r = cg_is_empty_recursive(SYSTEMD_CGROUP_CONTROLLER, u->cgroup_path, true);
if (r > 0) {
if (UNIT_VTABLE(u)->notify_cgroup_empty)
UNIT_VTABLE(u)->notify_cgroup_empty(u);
unit_add_to_gc_queue(u);
}
}
return 0;
}
static const char* const cgroup_device_policy_table[_CGROUP_DEVICE_POLICY_MAX] = {
[CGROUP_AUTO] = "auto",
[CGROUP_CLOSED] = "closed",
[CGROUP_STRICT] = "strict",
};
DEFINE_STRING_TABLE_LOOKUP(cgroup_device_policy, CGroupDevicePolicy);
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