diff options
Diffstat (limited to 'src/systemd-getty-generator/getty-generator.c')
| -rw-r--r-- | src/systemd-getty-generator/getty-generator.c | 233 |
1 files changed, 233 insertions, 0 deletions
diff --git a/src/systemd-getty-generator/getty-generator.c b/src/systemd-getty-generator/getty-generator.c new file mode 100644 index 0000000000..6e60cbab4f --- /dev/null +++ b/src/systemd-getty-generator/getty-generator.c @@ -0,0 +1,233 @@ +/*** + 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 <errno.h> +#include <fcntl.h> +#include <string.h> +#include <unistd.h> + +#include "systemd-basic/alloc-util.h" +#include "systemd-basic/fd-util.h" +#include "systemd-basic/fileio.h" +#include "systemd-basic/log.h" +#include "systemd-basic/mkdir.h" +#include "systemd-basic/path-util.h" +#include "systemd-basic/process-util.h" +#include "systemd-basic/string-util.h" +#include "systemd-basic/terminal-util.h" +#include "systemd-basic/unit-name.h" +#include "systemd-basic/util.h" +#include "systemd-basic/virt.h" + +static const char *arg_dest = "/tmp"; + +static int add_symlink(const char *fservice, const char *tservice) { + char *from, *to; + int r; + + assert(fservice); + assert(tservice); + + from = strjoina(SYSTEM_DATA_UNIT_PATH "/", fservice); + to = strjoina(arg_dest, "/getty.target.wants/", tservice); + + 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 > 0 ? -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" + "3270!tty1\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() > 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) { + const char *word, *state; + size_t l; + + FOREACH_WORD(word, l, container_ttys, state) { + const char *t; + char tty[l + 1]; + + memcpy(tty, word, 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) { + const char *word, *state; + size_t l; + + /* Automatically add in a serial getty on all active + * kernel consoles */ + FOREACH_WORD(word, l, active, state) { + _cleanup_free_ char *tty = NULL; + + tty = strndup(word, 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) { + char *p; + + p = strjoina("/sys/class/tty/", j); + if (access(p, F_OK) < 0) + continue; + + if (add_serial_getty(j) < 0) + return EXIT_FAILURE; + } + + return EXIT_SUCCESS; +} |