getty-generator.c revision 543407517e05688915128cfc544c5d7f97f240ef
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
/***
This file is part of systemd.
Copyright 2010 Lennart Poettering
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <fcntl.h>
#include "log.h"
#include "util.h"
#include "mkdir.h"
#include "unit-name.h"
#include "virt.h"
#include "fileio.h"
#include "path-util.h"
static const char *arg_dest = "/tmp";
static int add_symlink(const char *fservice, const char *tservice) {
_cleanup_free_ char *from = NULL, *to = NULL;
int r;
assert(fservice);
assert(tservice);
from = strappend(SYSTEM_DATA_UNIT_PATH "/", fservice);
if (!from)
return log_oom();
to = strjoin(arg_dest,"/getty.target.wants/", tservice, NULL);
if (!to)
return log_oom();
mkdir_parents_label(to, 0755);
r = symlink(from, to);
if (r < 0) {
if (errno == EEXIST)
/* In case console=hvc0 is passed this will very likely result in EEXIST */
return 0;
else {
log_error("Failed to create symlink %s: %m", to);
return -errno;
}
}
return 0;
}
static int add_serial_getty(const char *tty) {
_cleanup_free_ char *n = NULL;
assert(tty);
log_debug("Automatically adding serial getty for /dev/%s.", tty);
n = unit_name_replace_instance("serial-getty@.service", tty);
if (!n)
return log_oom();
return add_symlink("serial-getty@.service", n);
}
static int add_container_getty(const char *tty) {
_cleanup_free_ char *n = NULL;
assert(tty);
log_debug("Automatically adding container getty for /dev/pts/%s.", tty);
n = unit_name_replace_instance("container-getty@.service", tty);
if (!n)
return log_oom();
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 = strappenda("/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 ? -errno : -EIO;
return 0;
}
int main(int argc, char *argv[]) {
static const char virtualization_consoles[] =
"hvc0\0"
"xvc0\0"
"hvsi0\0"
"sclp_line0\0"
"ttysclp0\0";
_cleanup_free_ char *active = NULL;
const char *j;
int r;
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) {
_cleanup_free_ char *container_ttys = NULL;
log_debug("Automatically adding console shell.");
if (add_symlink("console-getty.service", "console-getty.service") < 0)
return EXIT_FAILURE;
/* 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. */
r = getenv_for_pid(1, "container_ttys", &container_ttys);
if (r > 0) {
char *w, *state;
size_t l;
FOREACH_WORD(w, l, container_ttys, state) {
const char *t;
char tty[l + 1];
memcpy(tty, w, l);
tty[l] = 0;
/* First strip off /dev/ if it is specified */
t = path_startswith(tty, "/dev/");
if (!t)
t = tty;
/* Then, make sure it's actually a pty */
t = path_startswith(t, "pts/");
if (!t)
continue;
if (add_container_getty(t) < 0)
return EXIT_FAILURE;
}
}
/* Don't add any further magic if we are in a container */
return EXIT_SUCCESS;
}
if (read_one_line_file("/sys/class/tty/console/active", &active) >= 0) {
char *w, *state;
size_t l;
/* Automatically add in a serial getty on all active
* kernel consoles */
FOREACH_WORD(w, l, active, state) {
_cleanup_free_ char *tty = NULL;
tty = strndup(w, l);
if (!tty) {
log_oom();
return EXIT_FAILURE;
}
if (isempty(tty) || tty_is_vc(tty))
continue;
if (verify_tty(tty) < 0)
continue;
/* We assume that gettys on virtual terminals are
* started via manual configuration and do this magic
* only for non-VC terminals. */
if (add_serial_getty(tty) < 0)
return EXIT_FAILURE;
}
}
/* Automatically add in a serial getty on the first
* virtualizer console */
NULSTR_FOREACH(j, virtualization_consoles) {
_cleanup_free_ char *p = NULL;
p = strappend("/sys/class/tty/", j);
if (!p) {
log_oom();
return EXIT_FAILURE;
}
if (access(p, F_OK) < 0)
continue;
if (add_serial_getty(j) < 0)
return EXIT_FAILURE;
}
return EXIT_SUCCESS;
}