att_lock/src/att_lock.h

#ifndef ATT_LOCK_H
#define ATT_LOCK_H

#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
#include <wayland-client.h>
#include <xkbcommon/xkbcommon.h>

/* 4x4 dot grid. Dot index = row * GRID_N + col, row/col in [0, GRID_N). */
#define GRID_N     4
#define DOT_COUNT  (GRID_N * GRID_N)
#define MAX_SEQ    DOT_COUNT

struct att;
struct att_output;

enum att_mode {
	MODE_UNLOCK,         /* verify a drawn pattern against the stored hash */
	MODE_SETUP_FIRST,    /* first run: draw a new pattern                 */
	MODE_SETUP_CONFIRM,  /* first run: draw it again to confirm           */
	MODE_PASSWORD,       /* PAM password fallback (keyboard entry)        */
};

enum att_feedback {
	FB_NONE,
	FB_ERROR,
	FB_OK,
};

/* Layout of the grid within one output, in surface-local (logical) pixels. */
struct grid {
	double ox, oy;   /* top-left of the grid square */
	double cell;     /* size of one cell            */
	double radius;   /* drawn dot radius            */
	double hit;      /* hit-test radius             */
};

struct att_pattern {
	int    seq[MAX_SEQ];
	int    len;
	bool   visited[DOT_COUNT];
	bool   drawing;
	double cur_x, cur_y;   /* live fingertip, in the active output's logical coords */
};

struct att_buffer {
	struct wl_buffer *wl_buffer;
	void   *data;
	size_t  size;
	int     width, height;   /* in device pixels */
	bool    busy;
};

struct att_output {
	struct wl_list      link;
	struct att         *app;
	struct wl_output   *wl_output;
	uint32_t            global_name;
	int32_t             scale;
	struct wl_surface  *surface;
	struct ext_session_lock_surface_v1 *lock_surface;
	int32_t             width, height;   /* logical size from configure */
	bool                configured;
	struct att_buffer   buffers[2];

	/* Output geometry as last advertised by wl_output. Only ever compared
	 * against the `cfg_*` snapshot below, never used to size a buffer: the
	 * buffer size must come from configure alone, and with fractional scale
	 * the integer wl_output.scale cannot reproduce the logical size anyway. */
	int32_t  mode_w, mode_h, transform;

	/* Same four values as of the most recent configure. A difference means
	 * the output changed and the compositor has not reconfigured us. */
	int32_t  cfg_mode_w, cfg_mode_h, cfg_transform, cfg_scale;

	/* Geometry we last recreated the lock surface for, so a compositor that
	 * ignores the recreate is nagged once rather than forever. */
	int32_t  retry_mode_w, retry_mode_h, retry_transform, retry_scale;
};

struct att_seat {
	struct wl_list       link;
	struct att          *app;
	struct wl_seat      *wl_seat;
	uint32_t             global_name;
	struct wl_pointer   *pointer;
	struct wl_touch     *touch;
	struct wl_keyboard  *keyboard;
	double               px, py;     /* latest pointer position (logical) */
	int32_t              touch_id;   /* active touch point, -1 if none */
	struct xkb_context  *xkb_ctx;
	struct xkb_keymap   *xkb_keymap;
	struct xkb_state    *xkb_state;
};

struct att {
	struct wl_display    *display;
	struct wl_registry   *registry;
	struct wl_compositor *compositor;
	struct wl_shm        *shm;
	struct ext_session_lock_manager_v1 *lock_manager;
	struct ext_session_lock_v1         *lock;

	struct wl_list outputs;   /* struct att_output.link */
	struct wl_list seats;     /* struct att_seat.link   */

	bool locked;
	bool running;
	bool dirty;

	enum att_mode     mode;
	enum att_feedback feedback;

	struct att_pattern  pattern;
	struct att_output  *active_output;   /* output currently receiving input */
	char  first_entry[128];              /* canonical string of first setup draw */

	char  password[256];
	int   password_len;

	/* Failed-attempt throttling. Kept in memory only: if this process dies
	 * the compositor keeps the session locked and there is no unlock UI at
	 * all, so there is no restart an attacker could use to clear these. */
	int      fail_count;     /* failed unlock attempts, pattern or password */
	int64_t  lockout_until;  /* CLOCK_MONOTONIC ms; 0 when not locked out   */

	/* CLOCK_MONOTONIC ms at which to re-examine output geometry, or 0. */
	int64_t  resize_recheck_at;

	/* configuration */
	const char *image_path;
	const char *pam_service;
	int         min_dots;

	void  *bg_surface;   /* cairo_surface_t*, or NULL */
	char  *hash_path;    /* XDG data path for the pattern hash */
};

/* main.c ------------------------------------------------------------------- */
int64_t att_now_ms(void);
int     att_lockout_secs(const struct att *app);   /* 0 when input is allowed */

/* pattern.c ---------------------------------------------------------------- */
void att_grid(const struct att_output *o, struct grid *g);
void pattern_reset(struct att_pattern *p);
int  pattern_hit(const struct grid *g, double x, double y);
void pattern_add(struct att_pattern *p, int idx);
int  pattern_to_string(const struct att_pattern *p, char *buf, size_t n);

/* render.c ----------------------------------------------------------------- */
void render_output(struct att_output *o);
void render_all(struct att *app);

/* image.c ------------------------------------------------------------------ */
/* PNG or PPM (P3/P6), by path or "-" for stdin. Returns a cairo_surface_t*,
 * or NULL after reporting why -- a missing background is never fatal. */
void *image_load(const char *path);

/* auth.c ------------------------------------------------------------------- */
enum auth_hash_state {
	AUTH_HASH_NONE,   /* no stored pattern yet                            */
	AUTH_HASH_STALE,  /* present but unreadable / written by an older ver */
	AUTH_HASH_OK,     /* usable with auth_verify()                        */
};

char *auth_hash_path(void);
enum auth_hash_state auth_hash_state(const char *path);
bool  auth_store(const char *path, const char *pattern_str);
bool  auth_verify(const char *path, const char *pattern_str);
bool  auth_pam(const char *service, const char *password);

#endif /* ATT_LOCK_H */