core: add an option to accept or discard command output

fixes #1973.

metadata/workarounds.xml

@@ -49,6 +49,10 @@
     <option name="enable_so_unloading" type="bool">
       <_short>Enable calling dlclose() when a plugin is unloaded. Note that this may not work well with all plugins.</_short>
       <default>false</default>
+    </option>
+    <option name="discard_command_output" type="bool">
+      <_short>Discard output from commands invoked by Wayfire, so that they don't end up in the logs.</_short>
+      <default>true</default>
     </option>
 	</plugin>
 </wayfire>

src/core/core-impl.hpp

@@ -81,6 +81,9 @@ class compositor_core_impl_t : public compositor_core_t
     compositor_state_t state = compositor_state_t::UNKNOWN;
     compositor_core_impl_t();
     virtual ~compositor_core_impl_t();
+
+  private:
+    wf::option_wrapper_t<bool> discard_command_output;
 };
 
 compositor_core_impl_t& get_core_impl();

src/core/core.cpp

@@ -216,6 +216,8 @@ void wf::compositor_core_impl_t::post_init()
     // Start processing cursor events
     seat->priv->cursor->setup_listeners();
 
+    discard_command_output.load_option("workarounds/discard_command_output");
+
     core_startup_finished_signal startup_ev;
     this->emit(&startup_ev);
 }
@@ -391,10 +393,13 @@ pid_t wf::compositor_core_impl_t::run(std::string command)
             }
 
 #endif
-            int dev_null = open("/dev/null", O_WRONLY);
-            dup2(dev_null, 1);
-            dup2(dev_null, 2);
-            close(dev_null);
+            if (discard_command_output)
+            {
+                int dev_null = open("/dev/null", O_WRONLY);
+                dup2(dev_null, 1);
+                dup2(dev_null, 2);
+                close(dev_null);
+            }
 
             _exit(execl("/bin/sh", "/bin/sh", "-c", command.c_str(), NULL));
         } else