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#include <assert.h>
#include <errno.h>
#include <fcntl.h>
#include <poll.h>
#include <stdbool.h>
#include <stdlib.h>
#include <string.h>
#include <signal.h>
#include <sys/socket.h>
#include <unistd.h>
#include "backend.h"
#include "log.h"
#include "terminal.h"
struct backend_noop {
struct libseat base;
const struct libseat_seat_listener *seat_listener;
void *seat_listener_data;
bool initial_setup;
int sockets[2];
};
static int vt;
bool should_reenable;
extern const struct seat_impl noop_impl;
static int vt_toggle(int vt, bool enable) {
int ttyfd = terminal_open(vt);
if (ttyfd == -1) {
log_errorf("Could not open terminal to switch to VT %d: %s", vt, strerror(errno));
return -1;
}
terminal_set_process_switching(ttyfd, true);
terminal_set_keyboard(ttyfd, !enable);
terminal_set_graphics(ttyfd, enable);
close(ttyfd);
return 0;
}
static struct backend_noop *backend_noop_from_libseat_backend(struct libseat *base) {
assert(base->impl == &noop_impl);
return (struct backend_noop *)base;
}
static void destroy(struct backend_noop *backend) {
close(backend->sockets[0]);
close(backend->sockets[1]);
free(backend);
}
static void vt_acq(int signal) {
(void)signal;
int ttyfd = terminal_open(vt);
if (ttyfd == -1) {
log_errorf("Could not open terminal to switch to VT %d: %s", vt, strerror(errno));
return;
}
terminal_ack_acquire(ttyfd);
close(ttyfd);
}
static void vt_rel(int signal) {
(void)signal;
int ttyfd = terminal_open(vt);
if (ttyfd == -1) {
log_errorf("Could not open terminal to switch to VT %d: %s",
vt, strerror(errno));
return;
}
terminal_ack_release(ttyfd);
vt_toggle(vt, false);
close(ttyfd);
}
static int close_seat(struct libseat *base) {
struct backend_noop *backend = backend_noop_from_libseat_backend(base);
destroy(backend);
return 0;
}
static int disable_seat(struct libseat *base) {
(void)base;
return 0;
}
static const char *seat_name(struct libseat *base) {
(void)base;
return "seat0";
}
static int open_device(struct libseat *base, const char *path, int *fd) {
(void)base;
int tmpfd = open(path, O_RDWR | O_NOCTTY | O_NOFOLLOW | O_CLOEXEC | O_NONBLOCK);
if (tmpfd < 0) {
log_errorf("Failed to open device: %s", strerror(errno));
return -1;
}
*fd = tmpfd;
return tmpfd;
}
static int close_device(struct libseat *base, int device_id) {
(void)base;
(void)device_id;
return 0;
}
static int switch_session(struct libseat *base, int s) {
struct backend_noop *backend = backend_noop_from_libseat_backend(base);
int ttyfd = terminal_open(vt);
if (ttyfd == -1) {
log_errorf("Could not open terminal to switch to VT %d: %s", vt, strerror(errno));
return -1;
}
backend->seat_listener->disable_seat(&backend->base, backend->seat_listener_data);
int ret = terminal_switch_vt(ttyfd, s);
should_reenable = false;
close(ttyfd);
return ret;
}
static int get_fd(struct libseat *base) {
struct backend_noop *backend = backend_noop_from_libseat_backend(base);
return backend->sockets[0];
}
static void noop(int signal) {
log_debugf("Handling sig %d", signal);
}
static int dispatch_background(struct libseat *base, int timeout) {
struct backend_noop *backend = backend_noop_from_libseat_backend(base);
if (backend->initial_setup) {
backend->initial_setup = false;
backend->seat_listener->enable_seat(&backend->base, backend->seat_listener_data);
}
if (should_reenable) {
backend->seat_listener->enable_seat(&backend->base, backend->seat_listener_data);
vt_toggle(vt, true);
should_reenable = false;
}
struct pollfd fd = {
.fd = backend->sockets[0],
.events = POLLIN,
};
if (poll(&fd, 1, timeout) < 0) {
if (errno == EAGAIN || errno == EINTR) {
return 0;
} else {
return -1;
}
}
return 0;
}
static struct libseat *noop_open_seat(const struct libseat_seat_listener *listener, void *data) {
struct backend_noop *backend = calloc(1, sizeof(struct backend_noop));
if (backend == NULL) {
return NULL;
}
if (socketpair(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, 0, backend->sockets) != 0) {
log_errorf("socketpair() failed: %s", strerror(errno));
free(backend);
return NULL;
}
int _vt;
const char *vt_env = getenv("LIBSEAT_VT");
if (!vt_env || (_vt = atoi(vt_env)) == 0) {
log_error("LIBSEAT_VT must be set to the current VT for the noop backend");
free(backend);
return NULL;
}
vt = _vt;
vt_toggle(vt, true);
{
struct sigaction sa;
sa.sa_handler = vt_rel;
sigemptyset(&sa.sa_mask);
sa.sa_flags = 0;
sigaction(SIGUSR1, &sa, NULL);
}
{
struct sigaction sa;
sa.sa_handler = vt_acq;
sigemptyset(&sa.sa_mask);
sa.sa_flags = 0;
sigaction(SIGUSR2, &sa, NULL);
}
backend->initial_setup = true;
backend->seat_listener = listener;
backend->seat_listener_data = data;
backend->base.impl = &noop_impl;
should_reenable = false;
return &backend->base;
}
const struct seat_impl noop_impl = {
.open_seat = noop_open_seat,
.disable_seat = disable_seat,
.close_seat = close_seat,
.seat_name = seat_name,
.open_device = open_device,
.close_device = close_device,
.switch_session = switch_session,
.get_fd = get_fd,
.dispatch = dispatch_background,
};
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