source: bootcd/isolinux/syslinux-6.03/com32/lib/syslinux/setup_data.c

#include <stdlib.h>
#include <syslinux/linux.h>
#include <syslinux/loadfile.h>

struct setup_data *setup_data_init(void)
{
    struct setup_data *setup_data;

    setup_data = zalloc(sizeof(*setup_data));
    if (!setup_data)
        return NULL;

    setup_data->prev = setup_data->next = setup_data;
    return setup_data;
}

int setup_data_add(struct setup_data *head, uint32_t type,
                   const void *data, size_t data_len)
{
        struct setup_data *setup_data;

        setup_data = zalloc(sizeof(*setup_data));
        if (!setup_data)
            return -1;

        setup_data->data     = data;
        setup_data->hdr.len  = data_len;
        setup_data->hdr.type = type;
        setup_data->prev     = head->prev;
        setup_data->next     = head;
        head->prev->next     = setup_data;
        head->prev           = setup_data;

        return 0;
}

int setup_data_load(struct setup_data *head, uint32_t type,
                    const char *filename)
{
        void *data;
        size_t len;

        if (loadfile(filename, &data, &len))
                return -1;

        return setup_data_add(head, type, data, len);
}