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/* SPDX-License-Identifier: LGPL-2.1-or-later */
#include <errno.h>
#include <fcntl.h>
#include <unistd.h>
#include "alloc-util.h"
#include "errno-util.h"
#include "fd-util.h"
#include "fileio.h"
#include "generator.h"
#include "log.h"
#include "mkdir-label.h"
#include "parse-util.h"
#include "path-util.h"
#include "process-util.h"
#include "proc-cmdline.h"
#include "strv.h"
#include "terminal-util.h"
#include "unit-name.h"
#include "util.h"
#include "virt.h"
static const char *arg_dest = NULL;
static bool arg_enabled = true;
static int add_symlink(const char *fservice, const char *tservice) {
char *from, *to;
int r;
assert(fservice);
assert(tservice);
from = strjoina(SYSTEM_DATA_UNIT_DIR "/", fservice);
to = strjoina(arg_dest, "/getty.target.wants/", tservice);
(void) mkdir_parents_label(to, 0755);
r = symlink(from, to);
if (r < 0) {
/* In case console=hvc0 is passed this will very likely result in EEXIST */
if (errno == EEXIST)
return 0;
return log_error_errno(errno, "Failed to create symlink %s: %m", to);
}
return 0;
}
static int add_serial_getty(const char *tty) {
_cleanup_free_ char *n = NULL;
int r;
assert(tty);
log_debug("Automatically adding serial getty for /dev/%s.", tty);
r = unit_name_from_path_instance("serial-getty", tty, ".service", &n);
if (r < 0)
return log_error_errno(r, "Failed to generate service name: %m");
return add_symlink("serial-getty@.service", n);
}
static int add_container_getty(const char *tty) {
_cleanup_free_ char *n = NULL;
int r;
assert(tty);
log_debug("Automatically adding container getty for /dev/pts/%s.", tty);
r = unit_name_from_path_instance("container-getty", tty, ".service", &n);
if (r < 0)
return log_error_errno(r, "Failed to generate service name: %m");
return add_symlink("container-getty@.service", n);
}
static int verify_tty(const char *name) {
_cleanup_close_ int fd = -1;
const char *p;
/* Some TTYs are weird and have been enumerated but don't work
* when you try to use them, such as classic ttyS0 and
* friends. Let's check that and open the device and run
* isatty() on it. */
p = strjoina("/dev/", name);
/* O_NONBLOCK is essential here, to make sure we don't wait
* for DCD */
fd = open(p, O_RDWR|O_NONBLOCK|O_NOCTTY|O_CLOEXEC|O_NOFOLLOW);
if (fd < 0)
return -errno;
errno = 0;
if (isatty(fd) <= 0)
return errno_or_else(EIO);
return 0;
}
static int run_container(void) {
_cleanup_free_ char *container_ttys = NULL;
int r;
log_debug("Automatically adding console shell.");
r = add_symlink("console-getty.service", "console-getty.service");
if (r < 0)
return r;
/* When $container_ttys is set for PID 1, spawn gettys on all ptys named therein.
* Note that despite the variable name we only support ptys here. */
(void) getenv_for_pid(1, "container_ttys", &container_ttys);
for (const char *p = container_ttys;;) {
_cleanup_free_ char *word = NULL;
r = extract_first_word(&p, &word, NULL, 0);
if (r < 0)
return log_error_errno(r, "Failed to parse $container_ttys: %m");
if (r == 0)
return 0;
const char *tty = word;
/* First strip off /dev/ if it is specified */
tty = path_startswith(tty, "/dev/") ?: tty;
/* Then, make sure it's actually a pty */
tty = path_startswith(tty, "pts/");
if (!tty)
continue;
r = add_container_getty(tty);
if (r < 0)
return r;
}
}
static int parse_proc_cmdline_item(const char *key, const char *value, void *data) {
int r;
assert(key);
if (proc_cmdline_key_streq(key, "systemd.getty_auto")) {
r = value ? parse_boolean(value) : 1;
if (r < 0)
log_warning_errno(r, "Failed to parse getty_auto switch \"%s\", ignoring: %m", value);
else
arg_enabled = r;
}
return 0;
}
static int run(const char *dest, const char *dest_early, const char *dest_late) {
_cleanup_free_ char *getty_auto = NULL;
int r;
assert_se(arg_dest = dest);
r = proc_cmdline_parse(parse_proc_cmdline_item, NULL, 0);
if (r < 0)
log_warning_errno(r, "Failed to parse kernel command line, ignoring: %m");
r = getenv_for_pid(1, "SYSTEMD_GETTY_AUTO", &getty_auto);
if (r < 0)
log_warning_errno(r, "Failed to parse $SYSTEMD_GETTY_AUTO environment variable, ignoring: %m");
else if (r > 0) {
r = parse_boolean(getty_auto);
if (r < 0)
log_warning_errno(r, "Failed to parse $SYSTEMD_GETTY_AUTO value \"%s\", ignoring: %m", getty_auto);
else
arg_enabled = r;
}
if (!arg_enabled) {
log_debug("Disabled, exiting.");
return 0;
}
if (detect_container() > 0)
/* Add console shell and look at $container_ttys, but don't do add any
* further magic if we are in a container. */
return run_container();
/* Automatically add in a serial getty on all active kernel consoles */
_cleanup_free_ char *active = NULL;
(void) read_one_line_file("/sys/class/tty/console/active", &active);
for (const char *p = active;;) {
_cleanup_free_ char *tty = NULL;
r = extract_first_word(&p, &tty, NULL, 0);
if (r < 0)
return log_error_errno(r, "Failed to parse /sys/class/tty/console/active: %m");
if (r == 0)
break;
/* We assume that gettys on virtual terminals are started via manual configuration and do
* this magic only for non-VC terminals. */
if (isempty(tty) || tty_is_vc(tty))
continue;
if (verify_tty(tty) < 0)
continue;
r = add_serial_getty(tty);
if (r < 0)
return r;
}
/* Automatically add in a serial getty on the first virtualizer console */
FOREACH_STRING(j,
"hvc0",
"xvc0",
"hvsi0",
"sclp_line0",
"ttysclp0",
"3270!tty1") {
_cleanup_free_ char *p = NULL;
p = path_join("/sys/class/tty", j);
if (!p)
return -ENOMEM;
if (access(p, F_OK) < 0)
continue;
r = add_serial_getty(j);
if (r < 0)
return r;
}
return 0;
}
DEFINE_MAIN_GENERATOR_FUNCTION(run);
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