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#pragma once
#include <camellia/flags.h>
#include <camellia/types.h>
#include <kernel/proc.h>
#include <stdbool.h>
#include <stddef.h>
// describes something which can act as an access function
struct vfs_backend {
size_t refcount;
/* references:
* struct vfs_mount
* struct vfs_request
* struct process
* struct handle
*/
bool heap;
size_t potential_handlers; // 0 - orphaned
struct vfs_request *queue;
bool is_user;
union {
struct {
struct process *handler;
} user;
struct {
bool (*ready)(struct vfs_backend *);
void (*accept)(struct vfs_request *);
} kern;
};
};
// describes an in-process vfs call
struct vfs_request {
enum vfs_operation type;
struct {
bool kern; // if false: use .buf ; if true: use .buf_kern
union {
char __user *buf;
char *buf_kern;
};
size_t len;
} input;
struct {
char __user *buf;
size_t len;
} output;
void __user *id; // handle.file.id
long offset;
int flags;
/* if caller != NULL, owned by it - don't free, the allocation will be reused
* if caller == NULL, free on finish */
struct process *caller;
struct vfs_backend *backend;
struct vfs_request *queue_next;
struct vfs_request *postqueue_next; /* used by kernel backends */
/* only one of these queues is in use at a given moment, they could
* be merged into a single field */
};
/** Assigns the vfs_request to the caller, and dispatches the call */
void vfsreq_create(struct vfs_request);
void vfsreq_finish(struct vfs_request*, char __user *stored, long ret, int flags, struct process *handler);
static inline void vfsreq_finish_short(struct vfs_request *req, long ret) {
vfsreq_finish(req, (void __user *)ret, ret, 0, NULL);
}
/** Try to accept an enqueued request */
void vfs_backend_tryaccept(struct vfs_backend *);
void vfs_backend_user_accept(struct vfs_request *req);
void vfs_backend_refdown(struct vfs_backend *);
#define BACKEND_KERN(ready, accept) ((struct vfs_backend){\
.is_user = false, \
.heap = false, \
.potential_handlers = 1, \
.refcount = 1, \
.kern = {ready, accept}})
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