save/restore the tty

Save the tty configuration before calling lxc_start and
restore it right after it has been changed.

Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>

diff --git a/src/lxc/lxc_start.c b/src/lxc/lxc_start.c
index cfdb17a37c26d40d783d0f9f51dd6df69b0ea86b..8db3bd3c703e318db75154057d88fdb63c8c2368 100644 (file)
--- a/src/lxc/lxc_start.c
+++ b/src/lxc/lxc_start.c
@@ -26,6 +26,7 @@
 #include <string.h>
 #include <termios.h>
 #include <errno.h>
+#include <signal.h>
 #include <sys/param.h>
 #include <sys/utsname.h>
 #include <sys/types.h>
@@ -58,6 +59,46 @@ Options :\n\
        .checker  = NULL,
 };
 
+static int save_tty(struct termios *tios)
+{
+       if (!isatty(0))
+               return 0;
+
+       if (tcgetattr(0, tios))
+               WARN("failed to get current terminal settings : %s",
+                    strerror(errno));
+
+       return 0;
+}
+
+static int restore_tty(struct termios *tios)
+{
+       struct termios current_tios;
+       void (*oldhandler)(int);
+       int ret;
+
+       if (!isatty(0))
+               return 0;
+
+       if (tcgetattr(0, &current_tios)) {
+               ERROR("failed to get current terminal settings : %s",
+                     strerror(errno));
+               return -1;
+       }
+
+       if (!memcmp(tios, &current_tios, sizeof(*tios)))
+               return 0;
+
+
+       oldhandler = signal(SIGTTOU, SIG_IGN);
+       ret = tcsetattr(0, TCSADRAIN, tios);
+       if (ret)
+               ERROR("failed to restore terminal attributes");
+       signal(SIGTTOU, oldhandler);
+
+       return ret;
+}
+
 int main(int argc, char *argv[])
 {
        char *const *args;
@@ -81,17 +122,11 @@ int main(int argc, char *argv[])
                         my_args.progname, my_args.quiet))
                return err;
 
-       if (tcgetattr(0, &tios)) {
-               ERROR("failed to get current terminal settings : %s",
-                     strerror(errno));
-               return err;
-       }
+       save_tty(&tios);
 
        err = lxc_start(my_args.name, args);
 
-       if (tcsetattr(0, TCSAFLUSH, &tios))
-               ERROR("failed to restore terminal settings : %s",
-                     strerror(errno));
+       restore_tty(&tios);
 
        return err;
 }