bool tty_is_vc_resolve(const char *tty) {
_cleanup_free_ char *active = NULL;
assert(tty);
if (startswith(tty, "/dev/"))
tty += 5;
if (streq(tty, "console")) {
tty = resolve_dev_console(&active);
if (!tty)
return false;
}
return tty_is_vc(tty);
}
int vt_disallocate(const char *name) {
int fd, r;
unsigned u;
/* Deallocate the VT if possible. If not possible
* (i.e. because it is the active one), at least clear it
* entirely (including the scrollback buffer) */
if (!startswith(name, "/dev/"))
return -EINVAL;
if (!tty_is_vc(name)) {
/* So this is not a VT. I guess we cannot deallocate
* it then. But let's at least clear the screen */
fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC);
if (fd < 0)
return fd;
loop_write(fd,
"\033[r" /* clear scrolling region */
"\033[H" /* move home */
"\033[2J", /* clear screen */
10, false);
safe_close(fd);
return 0;
}
if (!startswith(name, "/dev/tty"))
return -EINVAL;
r = safe_atou(name+8, &u);
if (r < 0)
return r;
if (u <= 0)
return -EINVAL;
/* Try to deallocate */
fd = open_terminal("/dev/tty0", O_RDWR|O_NOCTTY|O_CLOEXEC|O_NONBLOCK);
if (fd < 0)
return fd;
r = ioctl(fd, VT_DISALLOCATE, u);
safe_close(fd);
if (r >= 0)
return 0;
if (errno != EBUSY)
return -errno;
/* Couldn't deallocate, so let's clear it fully with
* scrollback */
fd = open_terminal(name, O_RDWR|O_NOCTTY|O_CLOEXEC);
if (fd < 0)
return fd;
loop_write(fd,
"\033[r" /* clear scrolling region */
"\033[H" /* move home */
"\033[3J", /* clear screen including scrollback, requires Linux 2.6.40 */
10, false);
safe_close(fd);
return 0;
}
int main(int argc, char *argv[]) {
static const char virtualization_consoles[] =
"hvc0\0"
"xvc0\0"
"hvsi0\0";
int r = EXIT_SUCCESS;
char *active;
const char *j;
if (argc > 1 && argc != 4) {
log_error("This program takes three or no arguments.");
return EXIT_FAILURE;
}
if (argc > 1)
arg_dest = argv[1];
log_set_target(LOG_TARGET_SAFE);
log_parse_environment();
log_open();
umask(0022);
if (detect_container(NULL) > 0) {
log_debug("Automatically adding console shell.");
if (add_symlink("console-getty.service", "console-getty.service") < 0)
r = EXIT_FAILURE;
/* Don't add any further magic if we are in a container */
goto finish;
}
if (read_one_line_file("/sys/class/tty/console/active", &active) >= 0) {
const char *tty;
tty = strrchr(active, ' ');
if (tty)
tty ++;
else
tty = active;
/* Automatically add in a serial getty on the kernel
* console */
if (isempty(tty) || tty_is_vc(tty))
free(active);
else {
int k;
/* We assume that gettys on virtual terminals are
* started via manual configuration and do this magic
* only for non-VC terminals. */
k = add_serial_getty(tty);
free(active);
if (k < 0) {
r = EXIT_FAILURE;
goto finish;
}
}
}
/* Automatically add in a serial getty on the first
* virtualizer console */
NULSTR_FOREACH(j, virtualization_consoles) {
char *p;
int k;
if (asprintf(&p, "/sys/class/tty/%s", j) < 0) {
log_oom();
r = EXIT_FAILURE;
goto finish;
}
k = access(p, F_OK);
free(p);
if (k < 0)
continue;
k = add_serial_getty(j);
if (k < 0) {
r = EXIT_FAILURE;
goto finish;
}
}
