exec: hangup/reset/deallocate VTs in gettys

Explicitly disconnect all clients from a VT when a getty starts/finishes
(requires TIOCVHANGUP, available in 2.6.29).

Explicitly deallocate getty VTs in order to flush scrollback buffer.

Explicitly reset terminals to a defined state before spawning getty.

1 files changed, 30 insertions, 5 deletions

diff --git a/src/execute.c b/src/execute.c
index 745dcfcdb8..a62f9dbbc6 100644
--- a/src/execute.c
+++ b/src/execute.c
@@ -140,6 +140,19 @@ static const char *tty_path(const ExecContext *context) {
         return "/dev/console";
 }
 
+void exec_context_tty_reset(const ExecContext *context) {
+        assert(context);
+
+        if (context->tty_vhangup)
+                terminal_vhangup(tty_path(context));
+
+        if (context->tty_reset)
+                reset_terminal(tty_path(context));
+
+        if (context->tty_vt_disallocate && context->tty_path)
+                vt_disallocate(context->tty_path);
+}
+
 static int open_null_as(int flags, int nfd) {
         int fd, r;
 
@@ -1089,6 +1102,8 @@ int exec_spawn(ExecCommand *command,
                         }
                 }
 
+                exec_context_tty_reset(context);
+
                 /* We skip the confirmation step if we shall not apply the TTY */
                 if (confirm_spawn &&
                     (!is_terminal_input(context->std_input) || apply_tty_stdin)) {
@@ -1700,8 +1715,14 @@ void exec_context_dump(ExecContext *c, FILE* f, const char *prefix) {
 
         if (c->tty_path)
                 fprintf(f,
-                        "%sTTYPath: %s\n",
-                        prefix, c->tty_path);
+                        "%sTTYPath: %s\n"
+                        "%sTTYReset: %s\n"
+                        "%sTTYVHangup: %s\n"
+                        "%sTTYVTDisallocate: %s\n",
+                        prefix, c->tty_path,
+                        prefix, yes_no(c->tty_reset),
+                        prefix, yes_no(c->tty_vhangup),
+                        prefix, yes_no(c->tty_vt_disallocate));
 
         if (c->std_output == EXEC_OUTPUT_SYSLOG || c->std_output == EXEC_OUTPUT_KMSG ||
             c->std_output == EXEC_OUTPUT_SYSLOG_AND_CONSOLE || c->std_output == EXEC_OUTPUT_KMSG_AND_CONSOLE ||
@@ -1802,7 +1823,7 @@ void exec_status_start(ExecStatus *s, pid_t pid) {
         dual_timestamp_get(&s->start_timestamp);
 }
 
-void exec_status_exit(ExecStatus *s, pid_t pid, int code, int status, const char *utmp_id) {
+void exec_status_exit(ExecStatus *s, ExecContext *context, pid_t pid, int code, int status) {
         assert(s);
 
         if ((s->pid && s->pid != pid) ||
@@ -1815,8 +1836,12 @@ void exec_status_exit(ExecStatus *s, pid_t pid, int code, int status, const char
         s->code = code;
         s->status = status;
 
-        if (utmp_id)
-                utmp_put_dead_process(utmp_id, pid, code, status);
+        if (context) {
+                if (context->utmp_id)
+                        utmp_put_dead_process(context->utmp_id, pid, code, status);
+
+                exec_context_tty_reset(context);
+        }
 }
 
 void exec_status_dump(ExecStatus *s, FILE *f, const char *prefix) {