package stopevidence

import "errors"

// ErrForeignHolder is a database descriptor that root's observation cannot
// attribute to the admitted session's replicator.
var ErrForeignHolder = errors.New("stopevidence: a descriptor other than the replicator's holds the database")

// Descriptor is one open descriptor root observed holding a watched file:
// the process, the task whose table showed it, the descriptor number and
// the open file's device and inode. A zero identity is a match by name
// whose file could not be reached.
type Descriptor struct {
	PID    int    `json:"pid"`
	TID    int    `json:"tid"`
	FD     int    `json:"fd"`
	Device uint64 `json:"device"`
	Inode  uint64 `json:"inode"`
}

// DescriptorHint is the agent's record of one of its own replicator's
// descriptors, taken from its own table when the replicator opened. It is a
// narrowing hint only (claim Plan 11, R3): root exempts a descriptor only
// when its own scan finds it in the agent's authenticated process, at this
// number, on this file. A hint never adds a holder or names a process.
type DescriptorHint struct {
	FD     int    `json:"fd"`
	Device uint64 `json:"device"`
	Inode  uint64 `json:"inode"`
}

// FileIdentity names a file by device and inode, as the launch journal
// records it.
type FileIdentity struct {
	Device uint64 `json:"device"`
	Inode  uint64 `json:"inode"`
}

// Agent is the authenticated agent process root observed on its socket:
// its pid and its start time (field 22 of /proc/<pid>/stat). Root takes
// both from the peer credentials, never from a request.
type Agent struct {
	PID   int
	Start string
}