RossComputerGuy/stardustos

/**
 * NewLand Kernel - (C) 2019 Tristan Ross
 */
#include <newland/alloc.h>
#include <newland/dev.h>
#include <newland/errno.h>

SLIST_HEAD(dev_list, device_t);
static struct dev_list devices = { NULL };
static size_t dev_count = 0;

size_t device_count() {
    return dev_count;
}

size_t device_indexof(device_t* device) {
    device_t* dev = NULL;
    size_t index = 0;
    SLIST_FOREACH(dev, &devices, dev_list) {
        if (!strcmp(dev->name, device->name)) return index;
        index++;
    }
    return -1;
}

device_t* device_get(size_t i) {
    device_t* device = NULL;
    size_t index = 0;
    SLIST_FOREACH(device, &devices, dev_list) {
        if (index == i) return device;
        index++;
    }
    return NULL;
}

device_t* device_fromdev(dev_t dev) {
    device_t* device = NULL;
    SLIST_FOREACH(device, &devices, dev_list) {
        if (device->dev == dev) return device;
    }
    return NULL;
}

device_t* device_fromname(const char* name) {
    if (strlen(name) > NAME_MAX) return NULL;
    device_t* device = NULL;
    SLIST_FOREACH(device, &devices, dev_list) {
        if (!strcmp(device->name, name)) return device;
    }
    return NULL;
}

int register_device(dev_t dev, const char* name, fs_node_opts_t opts, size_t size) {
    if (strlen(name) > NAME_MAX) return -NEWLAND_ENAMETOOLONG;
    if (device_fromname(name) != NULL || device_fromdev(dev) != NULL) return -NEWLAND_EEXIST;
    device_t* device = kmalloc(sizeof(device_t));
    if (device == NULL) return -NEWLAND_ENOMEM;
    device->dev = dev;
    device->size = size;
    strcpy((char*)device->name, name);
    device->opts = opts;
    SLIST_INSERT_HEAD(&devices, device, dev_list);
    dev_count++;
    return 0;
}

int unregister_device(dev_t dev) {
    device_t* device = device_fromdev(dev);
    if (device == NULL) return -NEWLAND_ENODEV;
    SLIST_REMOVE(&devices, device, device_t, dev_list);
    dev_count--;
    kfree(device);
    return 0;
}