diff options
Diffstat (limited to 'src/getty-generator/getty-generator.c')
| -rw-r--r-- | src/getty-generator/getty-generator.c | 206 |
1 files changed, 206 insertions, 0 deletions
diff --git a/src/getty-generator/getty-generator.c b/src/getty-generator/getty-generator.c new file mode 100644 index 0000000..35501b6 --- /dev/null +++ b/src/getty-generator/getty-generator.c @@ -0,0 +1,206 @@ +/* SPDX-License-Identifier: LGPL-2.1+ */ + +#include <errno.h> +#include <fcntl.h> +#include <string.h> +#include <unistd.h> + +#include "alloc-util.h" +#include "fd-util.h" +#include "fileio.h" +#include "generator.h" +#include "log.h" +#include "mkdir.h" +#include "path-util.h" +#include "process-util.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 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; +} + +static int run(const char *dest, const char *dest_early, const char *dest_late) { + _cleanup_free_ char *active = NULL; + const char *j; + int r; + + assert_se(arg_dest = dest); + + if (detect_container() > 0) { + _cleanup_free_ char *container_ttys = NULL; + + 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. */ + + 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; + + r = add_container_getty(t); + if (r < 0) + return r; + } + } + + /* Don't add any further magic if we are in a container */ + return 0; + } + + 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) + return log_oom(); + + /* 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") { + const char *p; + + p = strjoina("/sys/class/tty/", j); + if (access(p, F_OK) < 0) + continue; + + r = add_serial_getty(j); + if (r < 0) + return r; + } + + return 0; +} + +DEFINE_MAIN_GENERATOR_FUNCTION(run); |