add vty_is_active()

For async callbacks it is useful to determine whether a given VTY pointer is still valid.

For example, in osmo-msc, a silent call can be triggered by VTY, which causes a
Paging. The paging_cb then writes to the VTY console that the silent call has
succeeded. Unless the telnet vty session has already ended, in which case
osmo-msc crashes; e.g. from an osmo_interact_vty.py command invocation. With
this function, osmo-msc can ask whether the vty pointer passed to the paging
callback is still active, and skip vty_out() if not.

Change-Id: I42cf2af47283dd42c101faae0fac293c3a68d599

1 files changed, 2 insertions, 0 deletions

diff --git a/include/osmocom/vty/vty.h b/include/osmocom/vty/vty.h
index 8d2e1b36..03a29248 100644
--- a/include/osmocom/vty/vty.h
+++ b/include/osmocom/vty/vty.h
@@ -2,6 +2,7 @@
 
 #include <stdio.h>
 #include <stdarg.h>
+#include <stdbool.h>
 
 #include <osmocom/core/linuxlist.h>
 
@@ -192,6 +193,7 @@ void vty_init_vtysh (void);
 void vty_reset (void);
 struct vty *vty_new (void);
 struct vty *vty_create (int vty_sock, void *priv);
+bool vty_is_active(struct vty *vty);
 int vty_out (struct vty *, const char *, ...) VTY_PRINTF_ATTRIBUTE(2, 3);
 int vty_out_va(struct vty *vty, const char *format, va_list ap);
 int vty_out_newline(struct vty *);