[gthumb] script: fixed task cancellation when using a shell script

[Paolo Bacchilega <paobac src gnome org>]

commit a1afc2f315ef2cfd8da36beeb05e1c5eff4b918e
Author: Paolo Bacchilega <paobac src gnome org>
Date:   Sat Feb 22 08:14:46 2020 +0100

    script: fixed task cancellation when using a shell script
    
    Kill the process group to stop the shell subprocess as well.

 extensions/list_tools/gth-script-task.c | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)
---
diff --git a/extensions/list_tools/gth-script-task.c b/extensions/list_tools/gth-script-task.c
index ed689e84..7a49db5c 100644
--- a/extensions/list_tools/gth-script-task.c
+++ b/extensions/list_tools/gth-script-task.c
@@ -95,6 +95,20 @@ watch_script_cb (GPid     pid,
 }
 
 
+static void
+child_setup (gpointer user_data)
+{
+       /* detach from the tty */
+
+       setsid ();
+
+       /* create a process group to kill all the child processes when
+        * canceling the operation. */
+
+       setpgid (0, 0);
+}
+
+
 static void
 _gth_script_task_exec (GthScriptTask *self)
 {
@@ -155,7 +169,7 @@ _gth_script_task_exec (GthScriptTask *self)
                                                   argv,
                                                   NULL,
                                                   G_SPAWN_DO_NOT_REAP_CHILD | G_SPAWN_SEARCH_PATH,
-                                                  NULL,
+                                                  child_setup,
                                                   NULL,
                                                   &self->priv->pid,
                                                   &error))
@@ -251,7 +265,7 @@ gth_script_task_cancelled (GthTask *task)
        self = GTH_SCRIPT_TASK (task);
 
        if (self->priv->pid != 0)
-               kill (self->priv->pid, SIGTERM);
+               killpg (self->priv->pid, SIGTERM);
 }