+
+
+inline static int init_gIOOptionsEntry(void)
+{
+ IORegistryEntry *entry;
+ void *nvram_entry;
+ volatile void **options;
+ int ret = -1;
+
+ if (gIOOptionsEntry)
+ return 0;
+
+ entry = IORegistryEntry::fromPath( "/options", gIODTPlane );
+ if (!entry)
+ return -1;
+
+ nvram_entry = (void *) OSDynamicCast(IODTNVRAM, entry);
+ if (!nvram_entry)
+ goto release;
+
+ options = (volatile void **) &gIOOptionsEntry;
+ if (!OSCompareAndSwapPtr(NULL, nvram_entry, options)) {
+ ret = 0;
+ goto release;
+ }
+
+ return 0;
+
+release:
+ entry->release();
+ return ret;
+
+}
+
+/* pass in a NULL value if you just want to figure out the len */
+boolean_t PEReadNVRAMProperty(const char *symbol, void *value,
+ unsigned int *len)
+{
+ OSObject *obj;
+ OSData *data;
+ unsigned int vlen;
+
+ if (!symbol || !len)
+ goto err;
+
+ if (init_gIOOptionsEntry() < 0)
+ goto err;
+
+ vlen = *len;
+ *len = 0;
+
+ obj = gIOOptionsEntry->getProperty(symbol);
+ if (!obj)
+ goto err;
+
+ /* convert to data */
+ data = OSDynamicCast(OSData, obj);
+ if (!data)
+ goto err;
+
+ *len = data->getLength();
+ vlen = min(vlen, *len);
+ if (value && vlen)
+ memcpy((void *) value, data->getBytesNoCopy(), vlen);
+
+ return TRUE;
+
+err:
+ return FALSE;
+}
+
+boolean_t
+PEWriteNVRAMBooleanProperty(const char *symbol, boolean_t value)
+{
+ const OSSymbol *sym = NULL;
+ OSBoolean *data = NULL;
+ bool ret = false;
+
+ if (symbol == NULL) {
+ goto exit;
+ }
+
+ if (init_gIOOptionsEntry() < 0) {
+ goto exit;
+ }
+
+ if ((sym = OSSymbol::withCStringNoCopy(symbol)) == NULL) {
+ goto exit;
+ }
+
+ data = value ? kOSBooleanTrue : kOSBooleanFalse;
+ ret = gIOOptionsEntry->setProperty(sym, data);
+
+ sym->release();
+
+ /* success, force the NVRAM to flush writes */
+ if (ret == true) {
+ gIOOptionsEntry->sync();
+ }
+
+exit:
+ return ret;
+}
+
+boolean_t PEWriteNVRAMProperty(const char *symbol, const void *value,
+ const unsigned int len)
+{
+ const OSSymbol *sym;
+ OSData *data;
+ bool ret = false;
+
+ if (!symbol || !value || !len)
+ goto err;
+
+ if (init_gIOOptionsEntry() < 0)
+ goto err;
+
+ sym = OSSymbol::withCStringNoCopy(symbol);
+ if (!sym)
+ goto err;
+
+ data = OSData::withBytes((void *) value, len);
+ if (!data)
+ goto sym_done;
+
+ ret = gIOOptionsEntry->setProperty(sym, data);
+ data->release();
+
+sym_done:
+ sym->release();
+
+ if (ret == true) {
+ gIOOptionsEntry->sync();
+ return TRUE;
+ }
+
+err:
+ return FALSE;
+}
+
+
+boolean_t PERemoveNVRAMProperty(const char *symbol)
+{
+ const OSSymbol *sym;
+
+ if (!symbol)
+ goto err;
+
+ if (init_gIOOptionsEntry() < 0)
+ goto err;
+
+ sym = OSSymbol::withCStringNoCopy(symbol);
+ if (!sym)
+ goto err;
+
+ gIOOptionsEntry->removeProperty(sym);
+
+ sym->release();
+
+ gIOOptionsEntry->sync();
+ return TRUE;
+
+err:
+ return FALSE;
+
+}
+