fix(exec): redirect app output to /dev/null

[nnyyxxxx]

fixes #9278

this is a better approach to #1000 and yes waybar opens lol unlike #1013

[nnyyxxxx]

left is after, right is before

[PaideiaDilemma]

Also it is the same as #1000 right?
Both MRs leave STDIN open. Is there a reason why? It still points to the tty I think.

I also looked into this (and generally process spawning)
Tried to figure out why #1000 originally caused problem without success. Whatever caused waybar not to start, has probably been fixed.
I think std* pointing to /dev/null should not cause any problems.

[nnyyxxxx]

i have tried before and after, this one fixes the problem where waybar does not spawn, the other one still has the same problem.

not the same

not sure why the original one causes the issue either tbh

[nnyyxxxx]

heres an updated version of #1000 if you want to test for yourself

diff.txt

[PaideiaDilemma]

I used this on latest commit

diff --git a/src/managers/KeybindManager.cpp b/src/managers/KeybindManager.cpp
index 8daa6838..768f3198 100644
--- a/src/managers/KeybindManager.cpp
+++ b/src/managers/KeybindManager.cpp
@@ -24,6 +24,8 @@
 #include <string>
 #include <string_view>
 #include <cstring>
+#include <fcntl.h>
+#include <paths.h>
 
 #include <hyprutils/string/String.hpp>
 #include <hyprutils/os/FileDescriptor.hpp>
@@ -967,6 +969,22 @@ uint64_t CKeybindManager::spawnRawProc(std::string args, PHLWORKSPACE pInitialWo
                 setenv(e.first.c_str(), e.second.c_str(), 1);
             }
             setenv("WAYLAND_DISPLAY", g_pCompositor->m_szWLDisplaySocket.c_str(), 1);
+            close(STDOUT_FILENO);
+            close(STDERR_FILENO);
+
+            int devnull = open(_PATH_DEVNULL, O_WRONLY);
+            if (devnull == -1) {
+                Debug::log(LOG, "Unable to open /dev/null for writing");
+            }
+
+            if (dup2(devnull, STDOUT_FILENO) == -1) {
+                Debug::log(LOG, "Unable to duplicate /dev/null to stdout");
+            }
+            if (dup2(devnull, STDERR_FILENO) == -1) {
+                Debug::log(LOG, "Unable to duplicate /dev/null to stderr");
+            }
+
+            close(devnull);
             execl("/bin/sh", "/bin/sh", "-c", args.c_str(), nullptr);
             // exit grandchild
             _exit(0);

And waybar opens just fine ???

[PaideiaDilemma]

Shouldn't they be functionally equivalent?

Maybe opening devnull can fail??

[nnyyxxxx]

i think the issue is that it does not open with an exec-once, not the fact that it doesnt open in general

[nnyyxxxx]

could you clarify which way you are talking about? ^^

[PaideiaDilemma]

shi* I forgot that I wrapped waybar in uwsm 🙃
Ok yeah I can repo and how the f does your patch work xDDD

[nnyyxxxx]

skillz

[PaideiaDilemma]

is it _PATH_DEVNULL?

[nnyyxxxx]

nope

[PaideiaDilemma]

It's actually the closing of the stdin and stdout that breaks it.
That is pretty weird.

[PaideiaDilemma]

But if it works it works I guess. And stdin? Is it best to just leave it pointing to the tty/pts?

[nnyyxxxx]

ye

[vaxerski]

I feel alive