[pcustom] Describe struct with struct member

[u0m3]

How does one describe a struct that has another struct as a member (or is it even possible)?

struct fosphor_cl_features
{
#define FLG_CL_GL_SHARING   (1<<0)
#define FLG_CL_NVIDIA_SM11  (1<<1)
#define FLG_CL_OPENCL_11    (1<<2)
#define FLG_CL_LOCAL_ATOMIC_EXT (1<<3)

    cl_device_type type;
    char vendor[128];
    unsigned long local_mem;
    int flags;
    int wg_size;
    int wg_size_dim[2];
};

struct fosphor_cl_state
{
    cl_platform_id   pl_id;
    cl_device_id     dev_id;
    cl_context       ctx;
    cl_command_queue cq;

    /* Features */
    struct fosphor_cl_features feat;

    /* FFT */
    cl_mem      mem_fft_in;
    cl_mem      mem_fft_out;
    cl_mem      mem_fft_win;

    cl_program  prog_fft;
    cl_kernel   kern_fft;

    float       *fft_win;
    int     fft_win_updated;

    /* Display */
    cl_mem      mem_waterfall;
    cl_mem      mem_histogram;
    cl_mem      mem_spectrum;

    cl_program  prog_display;
    cl_kernel   kern_display;

    /* Histogram range */
    float       histo_scale;
    float       histo_offset;

    /* State */
    int     waterfall_pos;
    enum {
        CL_BOOTING = 0,
        CL_PENDING,
        CL_READY,
    } state;
};

( code taken from https://github.com/osmocom/gr-fosphor/blob/master/lib/fosphor/cl.c )

[hugsy]

That's not implemented yet, but it's on the TODO list.

[Grazfather]

I played with this tonight. Shouldn't be too difficult.

We need a way to have structures reference eachother.

1. The name shoudn't have to be Template
2. We should allow more than one per file. Maybe they would be referenced by module? e.g. dt heap.main_arena, allowing something like heap.fast_bins to exist in the same module and obviously allow them to reference each other.
3. Should we allow inter-module? This gets a bit tricky because the importing between would be weird. I hacked this in a test module by editing sys.path which is very bad style

Note that this only works for embedded structures not pointers to structures.

[hugsy]

@Grazfather : I totally missed your comment on this ... I needed this feature on a CTF this weekend, so I was about to get to it. Do you already have a patch ready for that?

[Grazfather]

Mine is super ugly, but I can push it.

EDIT: https://github.com/Grazfather/gef/tree/embed

[hugsy]

I'll have a look but I've also started on my end 😄

[Grazfather]

For sure. It's easy enough to implement, I just wasn't sure a nice way to have the modules find each other (sys.path stuff) and how to make it look.

[hugsy]

For now, I'm using pcustom.struct_path to "manually" load the desired module (with imp): for every .py file in the directory, I am importing all classes from the variable exportables. This approach allows to not touch the Python path, but also to select which class are to be visible.

[hugsy]

This was fixed long ago.