libvirt/src/util/vircgrouppriv.h
Pavel Hrdina 48423a0b5d vircgroup: introduce virCgroupV2DevicesAttachProg
This function loads the BPF prog with prepared map into kernel and
attaches it into guest cgroup.  It can be also used to replace existing
program in the cgroup if we need to resize BPF map to store more rules
for devices. The old program will be closed and removed from kernel.

There are two possible ways how to create BPF program:

    - One way is to write simple C-like code which can by compiled into
      BPF object file which can be loaded into kernel using elfutils.

    - The second way is to define macros which look like assembler
      instructions and can be used directly to create BPF program that
      can be directly loaded into kernel.

Since the program is not too complex we can use the second option.

If there is no program, all devices are allowed, if there is some
program it is executed and based on the exit status the access is
denied for 0 and allowed for 1.

Our program will follow these rules:

    - first it will try to look for the specific key using major and
      minor to see if there is any rule for that specific device

    - if there is no specific rule it will try to look for any rule that
      matches only major of the device

    - if there is no match with major it will try the same but with
      minor of the device

    - as the last attempt it will try to look for rule for all devices
      and if there is no match it will return 0 to deny that access

Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
2019-11-15 12:58:05 +01:00

143 lines
4.6 KiB
C

/*
* vircgrouppriv.h: methods for managing control cgroups
*
* Copyright (C) 2011-2013 Red Hat, Inc.
* Copyright IBM Corp. 2008
*
* This library 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.
*
* This library 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 this library. If not, see
* <http://www.gnu.org/licenses/>.
*/
#ifndef LIBVIRT_VIRCGROUPPRIV_H_ALLOW
# error "vircgrouppriv.h may only be included by vircgroup.c or its test suite"
#endif /* LIBVIRT_VIRCGROUPPRIV_H_ALLOW */
#pragma once
#include "vircgroup.h"
#include "vircgroupbackend.h"
struct _virCgroupV1Controller {
int type;
char *mountPoint;
/* If mountPoint holds several controllers co-mounted,
* then linkPoint is path of the symlink to the mountPoint
* for just the one controller
*/
char *linkPoint;
char *placement;
};
typedef struct _virCgroupV1Controller virCgroupV1Controller;
typedef virCgroupV1Controller *virCgroupV1ControllerPtr;
struct _virCgroupV2Devices {
int mapfd;
int progfd;
ssize_t count;
ssize_t max;
};
typedef struct _virCgroupV2Devices virCgroupV2Devices;
typedef virCgroupV2Devices *virCgroupV2DevicesPtr;
struct _virCgroupV2Controller {
int controllers;
char *mountPoint;
char *placement;
virCgroupV2Devices devices;
};
typedef struct _virCgroupV2Controller virCgroupV2Controller;
typedef virCgroupV2Controller *virCgroupV2ControllerPtr;
struct _virCgroup {
char *path;
virCgroupBackendPtr backends[VIR_CGROUP_BACKEND_TYPE_LAST];
virCgroupV1Controller legacy[VIR_CGROUP_CONTROLLER_LAST];
virCgroupV2Controller unified;
};
int virCgroupSetValueRaw(const char *path,
const char *value);
int virCgroupGetValueRaw(const char *path,
char **value);
int virCgroupSetValueStr(virCgroupPtr group,
int controller,
const char *key,
const char *value);
int virCgroupGetValueStr(virCgroupPtr group,
int controller,
const char *key,
char **value);
int virCgroupSetValueU64(virCgroupPtr group,
int controller,
const char *key,
unsigned long long int value);
int virCgroupGetValueU64(virCgroupPtr group,
int controller,
const char *key,
unsigned long long int *value);
int virCgroupSetValueI64(virCgroupPtr group,
int controller,
const char *key,
long long int value);
int virCgroupGetValueI64(virCgroupPtr group,
int controller,
const char *key,
long long int *value);
int virCgroupPartitionEscape(char **path);
char *virCgroupGetBlockDevString(const char *path);
int virCgroupGetValueForBlkDev(const char *str,
const char *devPath,
char **value);
int virCgroupNew(pid_t pid,
const char *path,
virCgroupPtr parent,
int controllers,
virCgroupPtr *group);
int virCgroupNewPartition(const char *path,
bool create,
int controllers,
virCgroupPtr *group)
ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(4);
int virCgroupNewDomainPartition(virCgroupPtr partition,
const char *driver,
const char *name,
bool create,
virCgroupPtr *group)
ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2) ATTRIBUTE_NONNULL(5);
int virCgroupRemoveRecursively(char *grppath);
int virCgroupKillRecursiveInternal(virCgroupPtr group,
int signum,
virHashTablePtr pids,
int controller,
const char *taskFile,
bool dormdir);