RENAMED_SCRATCHPAD_PATCH: AppImage Fails to Launch

[n1ck3]

Hi,

First of all, thank you for the incredible work you've done with dwm-flexipatch. If it weren't for this project, I probably wouldn’t be using dwm due to the challenges of managing multiple patches. 🙏

I’m facing an issue with the RENAMED_SCRATCHPAD_PATCH while trying to set up two applications as scratchpads: bitwarden-desktop (installed via AUR) and plexamp (AppImage).

Bitwarden Setup

The bitwarden-desktop scratchpad works perfectly:

• Keybinding: I can toggle the scratchpad if it's running.
• Keybinding: It launches bitwarden if it's not running.

Plexamp Setup

However, the plexamp scratchpad setup is not functioning as expected:

• My configuration for plexamp matches that of bitwarden, with only the command differing.
• Keybinding: I can toggle the scratchpad if plexamp is already running.
• Keybinding: It does not launch when plexamp isn’t running.

Error Logs

When attempting to launch plexamp with the keybinding, I see the following error in the dwm logs:

terminate called after throwing an instance of 'std::runtime_error'
what():  Headless detection failed: unexpected exit code from xhost

Troubleshooting Steps

Here are the steps I’ve taken to troubleshoot the issue:

1. Binding the AppImage to launch with a regular non-scratchpad key: works.
2. Creating a launch script (plexamp.sh) and executing it in a shell: works.
3. Binding the scratchpad command in config.h to execute the plexamp.sh script: The script runs, but the AppImage doesn’t launch.
4. Testing with another AppImage: same result and error as plexamp.

Configuration Snippets

Here are the relevant excerpts from my config.h:

Scratchpad Commands

...
#if RENAMED_SCRATCHPADS_PATCH
static const char *plexspcmd_p[] = {"p", "/home/nicke/Applications/Plexamp-4.12.0_b485663b1703b7f9c635b26577fd4f95.AppImage", NULL};
static const char *bitwardenspcmd_b[] = {"b", "bitwarden-desktop", NULL};
...

Rules

...
#if RENAMED_SCRATCHPADS_PATCH
RULE(.instance = "plexamp", .scratchkey = 'p', .isfloating = 1)
RULE(.instance = "bitwarden", .scratchkey = 'b', .isfloating = 1)
...

Keybindings

...
#if RENAMED_SCRATCHPADS_PATCH
{ MODKEY|ShiftMask,             XK_p,          togglescratch,          {.v = plexspcmd_p } },
{ MODKEY|ShiftMask,             XK_b,          togglescratch,          {.v = bitwardenspcmd_b } },
...

---

I would appreciate any guidance or suggestions to resolve this issue. Thank you again for your wonderful work and support!

[bakkeby]

I have to say; impressive writeup. You haven't left anything out.

I am currently on holiday so don't have an opportunity to test, but here is my impression.

Considering troubleshooting step 1 where you say spawning the command works if using a normal keybinding rather than a scratchpad; I suspect that this may be due to the upstream changes to use sigaction, which the scratchpad implementation does not have.

dwm-flexipatch/patch/renamed_scratchpads.c

Lines 20 to 31 in fd6db40

	void spawnscratch(const Arg *arg)
	{
	if (fork() == 0) {
	if (dpy)
	close(ConnectionNumber(dpy));
	setsid();
	execvp(((char **)arg->v)[1], ((char **)arg->v)+1);
	fprintf(stderr, "dwm: execvp %s", ((char **)arg->v)[1]);
	perror(" failed");
	exit(EXIT_SUCCESS);
	}
	}

vs

dwm-flexipatch/dwm.c

Lines 4171 to 4179 in fd6db40

	setsid();
	sigemptyset(&sa.sa_mask);
	sa.sa_flags = 0;
	sa.sa_handler = SIG_DFL;
	sigaction(SIGCHLD, &sa, NULL);
	execvp(((char **)arg->v)[0], (char **)arg->v);
	die("dwm: execvp '%s' failed:", ((char **)arg->v)[0]);

Might be worth trying to add that to the scratchpad implementation to see if that fixes the issue.

[n1ck3]

Hi,

Thanks for a quick response.

I tried this, but please keep in mind that I am not a C programmer.

This is what my dwm-flexipatch/patch/renamed_scratchpads.c looks like when trying the change:

void spawnscratch(const Arg *arg)
{
        if (fork() == 0) {
                if (dpy)
                        close(ConnectionNumber(dpy));
                // setsid();
                // execvp(((char **)arg->v)[1], ((char **)arg->v)+1);
                // fprintf(stderr, "dwm: execvp %s", ((char **)arg->v)[1]);
                // perror(" failed");
                // exit(EXIT_SUCCESS);

                struct sigaction sa; // Had to add this because it was complaining when compiling otherwise.
                setsid();

                sigemptyset(&sa.sa_mask);
                sa.sa_flags = 0;
                sa.sa_handler = SIG_DFL;
                sigaction(SIGCHLD, &sa, NULL);

                execvp(((char **)arg->v)[0], (char **)arg->v);
                die("dwm: execvp '%s' failed:", ((char **)arg->v)[0]);
        }
}

Dwm compiles, but I get this error when trying to invoke the AppImage now:

dwm: execvp 'p' failed: No such file or directory

Anything that stands out to you right off the bat?

[bakkeby]

Yes. The execvp call, you should keep the original one. It looks slightly different as it skips the first character, which is used as the scratch key.

[n1ck3]

Hi again,

Thanks for the pointer. That worked like a charm.

I created a pull request on the changes for you to look over.

Thanks again!