Error while reading file from CDROM

[VinegarLove]

Hi,
I have an ELF Executable with some data files and I would like it to be packaged into an ISO readable by the emulator.

I'm currently facing the problem of loading files into memory only when the ELF is packaged inside the ISO.

Using PCSX2 and enabling host filesystem, I can successfully load the file via SDL2 API.

// Open the file
SDL_RWops *file = SDL_RWFromFile("host:DATA/TEST.TXT", "r");
if (!file) {
    printf("Failed to open file: %s\n", SDL_GetError());
    exit(1);
}

However, when I try to read from the packed ISO with the following line, the file won't load correctly.

SDL_RWops *file = SDL_RWFromFile("cdrom0:DATA/TEST.TXT", "r");

I've attached the logs.
You may notice that there's an instruction that says "cdrom0:DATATEST.TXT" without the "/", but the file gets load correctly while using the host filesystem.

Trying to read anything from cdrom0: result in the same error.
"is not a regular file or pipe"

While accessing to "host:" related path gives just
"No such file or directory"

It seems like the cdrom0 FS isn't mounted for some reason.

EDIT:
The iso is formatted with this command.

    "mkisofs",
    "-udf",
    "-iso-level", "1",
    "-V", "PS2APP_ISO",
    "-o", output_iso,
    "-file-mode", "0400",
    "-dir-mode", "0500",
    "-relaxed-filenames",
    "-duplicates-once",
    "-volset", "PS2APP_ISO",
    "-sysid", "PLAYSTATION",
    "-appid", "PS2APP",
    disk_folder

Any help is appreciated 🙏

Thanks.
pcsx2_log.txt

[israpps]

CDVDMAN.IRX (the module that registers the cdrom0:\ device) is the only one that expects windows-like paths with backslashes.

[VinegarLove]

I tried with both Unix and Windows like backslashes and it still doesn't work.
I think SDL converts the call to be Unix like under the hood, which is why in the log I always see:
host:/DATA/IMG.PNG
or
cdrom0:/DATA/IMG.PNG
no matter what.

I'll try using the module directly and give you a feedback.

[HudsonSchumaker]

@VinegarLove did you found the solution ? i am havinf the same issue.

[94BILLY]

@VinegarLove did you found the solution ? i am havinf the same issue.

The issue is likely that CDVDMAN.IRX isn't loaded or the path format is wrong. You should try:

1. Make sure CDVDMAN is loaded:
   Check your IRX loading order. You need something like:
   siop_reset();
   load_module("CDVDMAN.IRX");
   load_module("CDVD.IRX");
   Before trying to access cdrom0:.

2. Use the correct path format:
   PS2 expects backslashes (even on Unix):
   SDL_RWops *file = SDL_RWFromFile("cdrom0:\DATA\TEST.TXT", "r");
   SDL might be converting them, but CDVDMAN is picky about it.

3. If SDL still doesn't work, use the IOP directly:
   Instead of relying on SDL's path conversion, use the PS2's file APIs:
   int fd = open("cdrom0:\DATA\TEST.TXT", O_RDONLY);
   if (fd < 0) {
   printf("Failed to open: %d\n", fd);
   }

4. Check your ISO:
   Your mkisofs command looks reasonable, but try:

• Add -J for Joliet (better filename support)
• Use -graft-points if you're using graft syntax
• Test with a simple flat structure first (no subdirectories)

Most likely CDVDMAN.IRX just isn't loaded when you're testing. Start there.

Hope it helps!

[VinegarLove]

I haven't worked at the project for a long, long time.
For future readers, here's my steps and my findings.

I looked up at SDL3 source code and saw that, somehow, it substitute the main() of the original main program. That should initialize all the driver needed by SDL before hand, but for me it wasn't working. Something with the driver init didn't work and SDL sound module was crashing.

So I had to avoid this by defining SDL_MAIN_HANDLED before including SDL header.
This disable the hijacking main system of SDL.
After that, I initialize the drivers on my own, which is what the SDL Library was doing anyway.

However, I'm not sure why, I had to initialize them like this.

static void _reset_IOP(void) {
    SifInitRpc(0);
    while (!SifIopReset(NULL, 0)) {};
    while (!SifIopSync()) {};
    SifInitRpc(0);
    sbv_patch_enable_lmb();
    sbv_patch_disable_prefix_check();
}

And then call this, or whatever driver needed.

#include <ps2_all_drivers.h>
...
init_ps2_filesystem_driver();

After this, I/O worked fine.

[sp193]

In the homebrew world, we have to reset the IOP to clear out whatever modules that were already loaded, as there's no standard to what the loader (e.g. LaunchELF) had left loaded. In Sony software, the reboot is done to ensure that there's the right IOP module versions that fit the SDK version of the software. If you have to do this, it implies that you needed to clear out the modules because of some compatibility problem. Maybe this part of the main() function provided by SDL is weak.

[VinegarLove]

@sp193 Main function is this one
https://github.com/libsdl-org/SDL/blob/main/src/main/ps2/SDL_sysmain_runapp.c

I'll probably look at my code and refactor it. Thanks!

[tifasoftware]

@VinegarLove Can I see your full working code?