64DD titles can crash if stored on a read only volume as it tries to create ".disk_save" file.

[7oxicshadow]

As per the title, If a .disk_save file is required it will fail to create on a read only file system.

The following function blindly assumes that it can write to the path:

const char *get_dd_disk_save_path(const char* diskname, int save_format)
{
    char* newPath = (char*)malloc(PATH_MAX);
    strcpy(newPath, diskname);

    if(save_format == 0)
        strcat(newPath, ".disk_save");
    else
        strcat(newPath, ".ram");

    return newPath;
}

I am not familiar with the Retroarch API. Would it be possible to check if "savefile_directory" stored in the retroarch.cfg file is not NULL and use that instead?

Should the "savefile_directory" not be set, would it be possible to create a temporary file in ram or something? I noticed that there is a "save_format" variable that can be set to -1, would that work in this scenario?

[m4xw]

Generally mupen does not support running on readonly filesystems (exception being the angle branch). Few files need to be dropped, shader cache etc. Can't throw this through RA's io.

[m4xw]

Can consider adding some sanity checks tho

[7oxicshadow]

In my scenario only the rom is stored on a read only file system (NAS) but I can work around it by scripting the files to be copied to a temp ram drive before launching.

I agree that some sanity checks with feedback to the user would be handy.

[m4xw]

tbh the whole thing is quite janky. Currently causes me a bunch of conflicts so will have to rewrite all that media loader shenanigans. Theres a argument to be had to move this to savefiles, but theres some caveats iirc (that i dont fully recall)

[m4xw]

If u want to play around with it, feel free tho. Happy to accept any PR (but like i said, probably needs a rewrite anyway, including all the subsystem stuff)

[m4xw]

Some extra info, before i forget. Those codepaths exists first and foremost for static platforms (i.e. Switch). Subsystem is broken for them, so thats how the naming scheme came to be. For platforms where subsystem works its probably best to allow them as a optional input on selection. Iirc disk save is a copy of the disc with modifications applied so in that case it will be sub-ideal for your use case no matter what I fear

[m4xw]

Disk save / .ram in particular i just smacked in afterwards