118ecf3242
A session-device is a device that is bound to a seat and used by a
session-controller to run the session. This currently includes DRM, fbdev
and evdev devices. A session-device can be created via RequestDevice() on
the dbus API of the session. You can drop it via ReleaseDevice() again.
Once the session is destroyed or you drop control of the session, all
session-devices are automatically destroyed.
Session devices follow the session "active" state. A device can be
active/running or inactive/paused. Whenever a session is not the active
session, no session-device of it can be active. That is, if a session is
not in foreground, all session-devices are paused.
Whenever a session becomes active, all devices are resumed/activated by
logind. If it fails, a device may stay paused.
With every session-device you request, you also get a file-descriptor
back. logind keeps a copy of this fd and uses kernel specific calls to
pause/resume the file-descriptors. For example, a DRM fd is muted
by logind as long as a given session is not active. Hence, the fd of the
application is also muted. Once the session gets active, logind unmutes
the fd and the application will get DRM access again.
This, however, requires kernel support. DRM devices provide DRM-Master for
synchronization, evdev devices have EVIOCREVOKE (pending on
linux-input-ML). fbdev devices do not provide such synchronization methods
(and never will).
Note that for evdev devices, we call EVIOCREVOKE once a session gets
inactive. However, this cannot be undone (the fd is still valid but mostly
unusable). So we reopen a new fd once the session is activated and send it
together with the ResumeDevice() signal.
With this infrastructure in place, compositors can now run without
CAP_SYS_ADMIN (that is, without being root). They use RequestControl() to
acquire a session and listen for devices via udev_monitor. For every
device they want to open, they call RequestDevice() on logind. This
returns a fd which they can use now. They no longer have to open the
devices themselves or call any privileged ioctls. This is all done by
logind.
Session-switches are still bound to VTs. Hence, compositors will get
notified via the usual VT mechanisms and can cleanup their state. Once the
VT switch is acknowledged as usual, logind will get notified via sysfs and
pause the old-session's devices and resume the devices of the new session.
To allow using this infrastructure with systems without VTs, we provide
notification signals. logind sends PauseDevice("force") dbus signals to
the current session controller for every device that it pauses. And it
sends ResumeDevice signals for every device that it resumes. For
seats with VTs this is sent _after_ the VT switch is acknowledged. Because
the compositor already acknowledged that it cleaned-up all devices.
However, for seats without VTs, this is used to notify the active
compositor that the session is about to be deactivated. That is, logind
sends PauseDevice("force") for each active device and then performs the
session-switch. The session-switch changes the "Active" property of the
session which can be monitored by the compositor. The new session is
activated and the ResumeDevice events are sent.
For seats without VTs, this is a forced session-switch. As this is not
backwards-compatible (xserver actually crashes, weston drops the related
devices, ..) we also provide an acknowledged session-switch. Note that
this is never used for sessions with VTs. You use the acknowledged
VT-switch on these seats.
An acknowledged session switch sends PauseDevice("pause") instead of
PauseDevice("force") to the active session. It schedules a short timeout
and waits for the session to acknowledge each of them with
PauseDeviceComplete(). Once all are acknowledged, or the session ran out
of time, a PauseDevice("force") is sent for all remaining active devices
and the session switch is performed.
Note that this is only partially implemented, yet, as we don't allow
multi-session without VTs, yet. A follow up commit will hook it up and
implemented the acknowledgements+timeout.
The implementation is quite simple. We use major/minor exclusively to
identify devices on the bus. On RequestDevice() we retrieve the
udev_device from the major/minor and search for an existing "Device"
object. If no exists, we create it. This guarantees us that we are
notified whenever the device changes seats or is removed.
We create a new SessionDevice object and link it to the related Session
and Device. Session->devices is a hashtable to lookup SessionDevice
objects via major/minor. Device->session_devices is a linked list so we
can release all linked session-devices once a device vanishes.
Now we only have to hook this up in seat_set_active() so we correctly
change device states during session-switches. As mentioned earlier, these
are forced state-changes as VTs are currently used exclusively for
multi-session implementations.
Everything else are hooks to release all session-devices once the
controller changes or a session is closed or removed.
326 lines
7.5 KiB
C
326 lines
7.5 KiB
C
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
|
|
|
|
#pragma once
|
|
|
|
/***
|
|
This file is part of systemd.
|
|
|
|
Copyright 2010 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/>.
|
|
***/
|
|
|
|
/* Missing glibc definitions to access certain kernel APIs */
|
|
|
|
#include <sys/resource.h>
|
|
#include <sys/syscall.h>
|
|
#include <fcntl.h>
|
|
#include <stdlib.h>
|
|
#include <unistd.h>
|
|
#include <linux/oom.h>
|
|
#include <linux/input.h>
|
|
|
|
#ifdef HAVE_AUDIT
|
|
#include <libaudit.h>
|
|
#endif
|
|
|
|
#include "macro.h"
|
|
|
|
#ifdef ARCH_MIPS
|
|
#include <asm/sgidefs.h>
|
|
#endif
|
|
|
|
#ifndef RLIMIT_RTTIME
|
|
#define RLIMIT_RTTIME 15
|
|
#endif
|
|
|
|
#ifndef F_LINUX_SPECIFIC_BASE
|
|
#define F_LINUX_SPECIFIC_BASE 1024
|
|
#endif
|
|
|
|
#ifndef F_SETPIPE_SZ
|
|
#define F_SETPIPE_SZ (F_LINUX_SPECIFIC_BASE + 7)
|
|
#endif
|
|
|
|
#ifndef F_GETPIPE_SZ
|
|
#define F_GETPIPE_SZ (F_LINUX_SPECIFIC_BASE + 8)
|
|
#endif
|
|
|
|
#ifndef IP_FREEBIND
|
|
#define IP_FREEBIND 15
|
|
#endif
|
|
|
|
#ifndef OOM_SCORE_ADJ_MIN
|
|
#define OOM_SCORE_ADJ_MIN (-1000)
|
|
#endif
|
|
|
|
#ifndef OOM_SCORE_ADJ_MAX
|
|
#define OOM_SCORE_ADJ_MAX 1000
|
|
#endif
|
|
|
|
#ifndef AUDIT_SERVICE_START
|
|
#define AUDIT_SERVICE_START 1130 /* Service (daemon) start */
|
|
#endif
|
|
|
|
#ifndef AUDIT_SERVICE_STOP
|
|
#define AUDIT_SERVICE_STOP 1131 /* Service (daemon) stop */
|
|
#endif
|
|
|
|
#ifndef TIOCVHANGUP
|
|
#define TIOCVHANGUP 0x5437
|
|
#endif
|
|
|
|
#ifndef IP_TRANSPARENT
|
|
#define IP_TRANSPARENT 19
|
|
#endif
|
|
|
|
#if !HAVE_DECL_PIVOT_ROOT
|
|
static inline int pivot_root(const char *new_root, const char *put_old) {
|
|
return syscall(SYS_pivot_root, new_root, put_old);
|
|
}
|
|
#endif
|
|
|
|
#ifdef __x86_64__
|
|
# ifndef __NR_fanotify_init
|
|
# define __NR_fanotify_init 300
|
|
# endif
|
|
# ifndef __NR_fanotify_mark
|
|
# define __NR_fanotify_mark 301
|
|
# endif
|
|
#elif defined _MIPS_SIM
|
|
# if _MIPS_SIM == _MIPS_SIM_ABI32
|
|
# ifndef __NR_fanotify_init
|
|
# define __NR_fanotify_init 4336
|
|
# endif
|
|
# ifndef __NR_fanotify_mark
|
|
# define __NR_fanotify_mark 4337
|
|
# endif
|
|
# elif _MIPS_SIM == _MIPS_SIM_NABI32
|
|
# ifndef __NR_fanotify_init
|
|
# define __NR_fanotify_init 6300
|
|
# endif
|
|
# ifndef __NR_fanotify_mark
|
|
# define __NR_fanotify_mark 6301
|
|
# endif
|
|
# elif _MIPS_SIM == _MIPS_SIM_ABI64
|
|
# ifndef __NR_fanotify_init
|
|
# define __NR_fanotify_init 5295
|
|
# endif
|
|
# ifndef __NR_fanotify_mark
|
|
# define __NR_fanotify_mark 5296
|
|
# endif
|
|
# endif
|
|
#else
|
|
# ifndef __NR_fanotify_init
|
|
# define __NR_fanotify_init 338
|
|
# endif
|
|
# ifndef __NR_fanotify_mark
|
|
# define __NR_fanotify_mark 339
|
|
# endif
|
|
#endif
|
|
|
|
#ifndef HAVE_FANOTIFY_INIT
|
|
static inline int fanotify_init(unsigned int flags, unsigned int event_f_flags) {
|
|
return syscall(__NR_fanotify_init, flags, event_f_flags);
|
|
}
|
|
#endif
|
|
|
|
#ifndef HAVE_FANOTIFY_MARK
|
|
static inline int fanotify_mark(int fanotify_fd, unsigned int flags, uint64_t mask,
|
|
int dfd, const char *pathname) {
|
|
#if defined _MIPS_SIM && _MIPS_SIM == _MIPS_SIM_ABI32 || defined __powerpc__ && !defined __powerpc64__ \
|
|
|| defined __arm__ && !defined __aarch64__
|
|
union {
|
|
uint64_t _64;
|
|
uint32_t _32[2];
|
|
} _mask;
|
|
_mask._64 = mask;
|
|
|
|
return syscall(__NR_fanotify_mark, fanotify_fd, flags,
|
|
_mask._32[0], _mask._32[1], dfd, pathname);
|
|
#else
|
|
return syscall(__NR_fanotify_mark, fanotify_fd, flags, mask, dfd, pathname);
|
|
#endif
|
|
}
|
|
#endif
|
|
|
|
#ifndef BTRFS_IOCTL_MAGIC
|
|
#define BTRFS_IOCTL_MAGIC 0x94
|
|
#endif
|
|
|
|
#ifndef BTRFS_PATH_NAME_MAX
|
|
#define BTRFS_PATH_NAME_MAX 4087
|
|
#endif
|
|
|
|
#ifndef BTRFS_DEVICE_PATH_NAME_MAX
|
|
#define BTRFS_DEVICE_PATH_NAME_MAX 1024
|
|
#endif
|
|
|
|
#ifndef BTRFS_FSID_SIZE
|
|
#define BTRFS_FSID_SIZE 16
|
|
#endif
|
|
|
|
#ifndef BTRFS_UUID_SIZE
|
|
#define BTRFS_UUID_SIZE 16
|
|
#endif
|
|
|
|
#ifndef HAVE_LINUX_BTRFS_H
|
|
struct btrfs_ioctl_vol_args {
|
|
int64_t fd;
|
|
char name[BTRFS_PATH_NAME_MAX + 1];
|
|
};
|
|
|
|
struct btrfs_ioctl_dev_info_args {
|
|
uint64_t devid; /* in/out */
|
|
uint8_t uuid[BTRFS_UUID_SIZE]; /* in/out */
|
|
uint64_t bytes_used; /* out */
|
|
uint64_t total_bytes; /* out */
|
|
uint64_t unused[379]; /* pad to 4k */
|
|
char path[BTRFS_DEVICE_PATH_NAME_MAX]; /* out */
|
|
};
|
|
|
|
struct btrfs_ioctl_fs_info_args {
|
|
uint64_t max_id; /* out */
|
|
uint64_t num_devices; /* out */
|
|
uint8_t fsid[BTRFS_FSID_SIZE]; /* out */
|
|
uint64_t reserved[124]; /* pad to 1k */
|
|
};
|
|
#endif
|
|
|
|
#ifndef BTRFS_IOC_DEFRAG
|
|
#define BTRFS_IOC_DEFRAG _IOW(BTRFS_IOCTL_MAGIC, 2, struct btrfs_ioctl_vol_args)
|
|
#endif
|
|
|
|
#ifndef BTRFS_IOC_DEV_INFO
|
|
#define BTRFS_IOC_DEV_INFO _IOWR(BTRFS_IOCTL_MAGIC, 30, \
|
|
struct btrfs_ioctl_dev_info_args)
|
|
#endif
|
|
|
|
#ifndef BTRFS_IOC_FS_INFO
|
|
#define BTRFS_IOC_FS_INFO _IOR(BTRFS_IOCTL_MAGIC, 31, \
|
|
struct btrfs_ioctl_fs_info_args)
|
|
#endif
|
|
|
|
#ifndef BTRFS_SUPER_MAGIC
|
|
#define BTRFS_SUPER_MAGIC 0x9123683E
|
|
#endif
|
|
|
|
#ifndef MS_MOVE
|
|
#define MS_MOVE 8192
|
|
#endif
|
|
|
|
#ifndef MS_PRIVATE
|
|
#define MS_PRIVATE (1 << 18)
|
|
#endif
|
|
|
|
#if !HAVE_DECL_GETTID
|
|
static inline pid_t gettid(void) {
|
|
return (pid_t) syscall(SYS_gettid);
|
|
}
|
|
#endif
|
|
|
|
#ifndef SCM_SECURITY
|
|
#define SCM_SECURITY 0x03
|
|
#endif
|
|
|
|
#ifndef MS_STRICTATIME
|
|
#define MS_STRICTATIME (1<<24)
|
|
#endif
|
|
|
|
#ifndef MS_REC
|
|
#define MS_REC 16384
|
|
#endif
|
|
|
|
#ifndef MS_SHARED
|
|
#define MS_SHARED (1<<20)
|
|
#endif
|
|
|
|
#ifndef PR_SET_NO_NEW_PRIVS
|
|
#define PR_SET_NO_NEW_PRIVS 38
|
|
#endif
|
|
|
|
#ifndef PR_SET_CHILD_SUBREAPER
|
|
#define PR_SET_CHILD_SUBREAPER 36
|
|
#endif
|
|
|
|
#ifndef MAX_HANDLE_SZ
|
|
#define MAX_HANDLE_SZ 128
|
|
#endif
|
|
|
|
#if defined __x86_64__
|
|
# ifndef __NR_name_to_handle_at
|
|
# define __NR_name_to_handle_at 303
|
|
# endif
|
|
#elif defined __i386__
|
|
# ifndef __NR_name_to_handle_at
|
|
# define __NR_name_to_handle_at 341
|
|
# endif
|
|
#elif defined __arm__
|
|
# ifndef __NR_name_to_handle_at
|
|
# define __NR_name_to_handle_at 370
|
|
# endif
|
|
#elif defined __powerpc__
|
|
# ifndef __NR_name_to_handle_at
|
|
# define __NR_name_to_handle_at 345
|
|
# endif
|
|
#else
|
|
# ifndef __NR_name_to_handle_at
|
|
# error __NR_name_to_handle_at is not defined
|
|
# endif
|
|
#endif
|
|
|
|
#if !HAVE_DECL_NAME_TO_HANDLE_AT
|
|
struct file_handle {
|
|
unsigned int handle_bytes;
|
|
int handle_type;
|
|
unsigned char f_handle[0];
|
|
};
|
|
|
|
static inline int name_to_handle_at(int fd, const char *name, struct file_handle *handle, int *mnt_id, int flags) {
|
|
return syscall(__NR_name_to_handle_at, fd, name, handle, mnt_id, flags);
|
|
}
|
|
#endif
|
|
|
|
#ifndef HAVE_SECURE_GETENV
|
|
# ifdef HAVE___SECURE_GETENV
|
|
# define secure_getenv __secure_getenv
|
|
# else
|
|
# error neither secure_getenv nor __secure_getenv are available
|
|
# endif
|
|
#endif
|
|
|
|
#ifndef CIFS_MAGIC_NUMBER
|
|
#define CIFS_MAGIC_NUMBER 0xFF534D42
|
|
#endif
|
|
|
|
#ifndef TFD_TIMER_CANCEL_ON_SET
|
|
#define TFD_TIMER_CANCEL_ON_SET (1 << 1)
|
|
#endif
|
|
|
|
#ifndef SO_REUSEPORT
|
|
#define SO_REUSEPORT 15
|
|
#endif
|
|
|
|
#ifndef EVIOCREVOKE
|
|
#define EVIOCREVOKE _IOW('E', 0x91, int)
|
|
#endif
|
|
|
|
#ifndef DRM_IOCTL_SET_MASTER
|
|
#define DRM_IOCTL_SET_MASTER _IO('d', 0x1e)
|
|
#endif
|
|
|
|
#ifndef DRM_IOCTL_DROP_MASTER
|
|
#define DRM_IOCTL_DROP_MASTER _IO('d', 0x1f)
|
|
#endif
|