File: //usr/src/file_protector-1.1-1523/transport/transport.h
/**
@file
@brief Message transport between kernel and userspace
@details Copyright (c) 2017 Acronis International GmbH
@author Mikhail Krivtsov (mikhail.krivtsov@acronis.com)
@since $Id: $
*/
#pragma once
#include "ring.h"
#include "set.h"
#include "task_info_map.h"
#include <linux/fs.h>
#include <linux/types.h> // bool, [u]int(8|16|32|64)_t, pid_t
#include "transport_protocol.h"
// This is the header of the buffer that is 'mmap'd between kernel and user space.
// Both reader & write must use READ_ONCE/WRITE_ONCE/smp_* when accessing its contents.
typedef struct {
// 'head' and 'tail' is ring-like - reader reads from the 'head' and moves it to the 'tail'
// 'writer' moves the 'tail' as showing that more content is available.
// In our case, kernel=writer & userspace=reader
// Head is written only by userspace, it is specifying offset in 'entries' in bytes
// When head is written by userspace using 'smp_store_release', kernel must 'smp_load_acquire' it
uint32_t head ____cacheline_aligned_in_smp;
// Tail is written only by kernelspace, it is specifying offset in 'entries' in bytes
uint32_t tail ____cacheline_aligned_in_smp;
// Entries with the data, varsized struct where 'data_queue_entry_t' itself is varsized
data_queue_entry_t entries[0] ____cacheline_aligned_in_smp;
} shared_data_queue_t;
typedef struct {
struct list_head transport_list_node;
pid_t control_tgid;
atomic64_t events_mask;
// FIXME: Use 'msg_wait_queue.lock' instead of 'msg_spinlock'
// #define msg_spinlock msg_wait_queue.lock
spinlock_t msg_spinlock;
wait_queue_head_t msg_wait_queue;
atomic_t shutdown;
ring_t msg_ring;
// sent messages waiting for 'reply'
set_t sent_msgs_set;
uint32_t queue_size;
shared_data_queue_t *queue;
atomic_t queue_event;
unsigned char task_info_map_id;
} transport_t;
typedef struct {
struct mutex transport_mutex;
unsigned transport_count;
atomic64_t combined_events_mask;
spinlock_t transport_spinlock;
struct list_head transport_list;
msg_id_t msg_id_sequence;
} transport_global_t;
// 'module' 'init'/'down'
int transport_mod_init(void);
void transport_mod_down(void);
// 'device' 'fops'
int transport_device_open(struct inode *, struct file *);
long transport_device_ioctl(struct file *, unsigned int, unsigned long);
ssize_t transport_device_read(struct file *, char __user *, size_t, loff_t *);
ssize_t transport_device_write(struct file *, const char __user *, size_t,
loff_t *);
int transport_device_release(struct inode *, struct file *);
int transport_device_mmap(struct file *filp, struct vm_area_struct *vma);
uint64_t transport_global_get_combined_mask(void);