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#include <kernel/panic.h>
#include <kernel/proc.h>
#include <kernel/vfs/backend.h>
#include <kernel/vfs/root.h>
// dispatches a VFS operation to the correct process
_Noreturn void vfs_backend_dispatch(struct vfs_backend *backend, struct vfs_op op) {
struct vfs_op_request req = {
.op = op,
.caller = process_current,
.backend = backend,
};
switch (backend->type) {
case VFS_BACK_ROOT:
int ret = vfs_root_handler(&req);
vfs_backend_finish(&req, ret);
case VFS_BACK_USER:
process_current->state = PS_WAITS4FS;
if (backend->handler == NULL) { // backend not ready yet
if (backend->queue == NULL) {
backend->queue = process_current;
process_switch_any();
} else {
panic(); // TODO implement a proper queue
}
} else {
if (backend->handler->state != PS_WAITS4REQUEST)
panic(); // invalid state
panic(); // TODO
}
default:
panic();
}
}
// returns from a VFS operation to the calling process
_Noreturn void vfs_backend_finish(struct vfs_op_request *req, int ret) {
if (req->op.type == VFSOP_OPEN && ret >= 0) {
// open() calls need special handling
// we need to wrap the id returned by the VFS in a handle passed to
// the client
handle_t handle = process_find_handle(req->caller);
if (handle < 0) panic();
req->caller->handles[handle] = (struct handle){
.type = HANDLE_FILE,
.file = {
.backend = req->backend,
.id = ret,
},
};
ret = handle;
}
req->caller->state = PS_RUNNING;
regs_savereturn(&req->caller->regs, ret);
process_switch(req->caller);
}
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