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-rw-r--r--src/getty-generator/getty-generator.c206
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);