[Libguestfs] [PATCH] fish: reset the console on ^Z RHBZ#1213844

[Maros Zatko]

Patch registers SIGTSTP hook where it sends reset terminal color
control sequence.
---
 fish/fish.c | 72 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 72 insertions(+)

diff --git a/fish/fish.c b/fish/fish.c
index d26f8b3..b579898 100644
--- a/fish/fish.c
+++ b/fish/fish.c
@@ -73,6 +73,11 @@ static void cleanup_readline (void);
 static char *decode_ps1 (const char *);
 static void add_history_line (const char *);
 #endif
+static void set_stophandler (void);
+static void restore_stophandler (void);
+static void user_control_z (int sig);
+
+static void (*otstpfn) = SIG_DFL;
 
 static int override_progress_bars = -1;
 static struct progress_bar *bar = NULL;
@@ -159,6 +164,64 @@ usage (int status)
   exit (status);
 }
 
+/*
+ * Set the TSTP handler.
+ */
+static void
+set_stophandler (void)
+{
+  otstpfn = signal (SIGTSTP, user_control_z);
+}
+
+/*
+ * Restore the TSTP handler.
+ */
+static void
+restore_stophandler (void)
+{
+  signal (SIGTSTP, otstpfn);
+}
+
+static void
+user_control_z (int sig)
+{
+  sigset_t oset, set;
+
+#ifdef HAVE_LIBREADLINE
+  /* Cleanup readline, unhook from terminal */
+  rl_free_line_state ();
+  rl_cleanup_after_signal ();
+#endif
+
+  /* Reset terminal color */
+#define RESETCOLOR "\033[0m"
+  printf (RESETCOLOR);
+  fflush (stdout);
+
+  /* Unblock SIGTSTP. */
+  sigemptyset (&set);
+  sigaddset (&set, SIGTSTP);
+  sigprocmask (SIG_UNBLOCK, &set, NULL);
+
+  restore_stophandler ();
+
+  /* Stop ourselves. */
+  kill (0, SIGTSTP);
+
+  /* Now we're stopped ... */
+
+  /* Reset the curses SIGTSTP signal handler. */
+  set_stophandler ();
+
+#ifdef HAVE_LIBREADLINE
+  /* Restore readline state */
+  rl_reset_after_signal ();
+#endif
+
+  /* Reset the signals. */
+  sigprocmask (SIG_SETMASK, &oset, NULL);
+}
+
 int
 main (int argc, char *argv[])
 {
@@ -439,6 +502,15 @@ main (int argc, char *argv[])
       exit (EXIT_FAILURE);
   }
 
+  /* Register ^Z handler. We need it to reset terminal colors
+   */
+  if (is_interactive) {
+    memset (&sa, 0, sizeof sa);
+    sa.sa_handler = user_control_z;
+    sa.sa_flags = SA_RESTART;
+    sigaction (SIGTSTP, &sa, NULL);
+  }
+
   /* Old-style -i syntax?  Since -a/-d/-N and -i was disallowed
    * previously, if we have -i without any drives but with something
    * on the command line, it must be old-style syntax.
-- 
2.5.0