Im honestly a bit lost and looking for general pointers. Here is the general flow of my project. I have an Xcode project where I want to return and convert the temperature values accessed from the apple smc and I found a GitHub repo with all the smc key sensors for the M3Pros/Max chips: https://github.com/exelban/stats/issues/1703 basically, I have all these keys stored in an array in obj-c like so:
NSArray *smcKeys = @[ @"Tp01", @"Tp05", @"Tp09", @"Tp0D", @"Tp0b", @"Tp0f", @"Tp0j", @"Tp0n",@"Tp0h", @"Tp0L", @"Tp0S", @"Tp0V", @"Tp0z", @"Tp0v", @"Tp17", @"Tp1F", @"Tp1J", @"Tp1p", @"Tp1h", @"Tp1R", ];
I am passing all these keys by passing 'smcKeys' in a regular C code file I have here that is meant to open, close and read the data shown here:
#include "smc.h"
#include <mach/mach.h>
#include <IOKit/IOKitLib.h>
#include "smckeys.h"
io_connect_t conn;
kern_return_t openSMC(void) {
kern_return_t result;
kern_return_t service;
io_iterator_t iterator;
service = IOServiceGetMatchingServices(kIOMainPortDefault, IOServiceMatching("AppleSMC"), &iterator);
if(service == 0) {
printf("error: could not match dictionary");
return 0;
}
result = IOServiceOpen(service, mach_task_self(), 0, &conn);
IOObjectRelease(service);
return 0;
}
kern_return_t closeSMC(void) {
return IOServiceClose(conn);
}
kern_return_t readSMC(char *smcKeys, SMCVal_t *val) {
kern_return_t result;
uint32_t keyCode = *(uint32_t *)smcKeys;
SMCVal_t inputStruct;
SMCVal_t outputStruct;
inputStruct.datasize = sizeof(SMCVal_t);
inputStruct.datatype = 'I' << 24; //a left shift operation. turning the I into an int by shifting the ASCII value 24 bits to the left
inputStruct.data[0] = keyCode;
result = IOConnectCallStructMethod(conn, 5, &inputStruct, sizeof(SMCVal_t), &outputStruct, (size_t*)&inputStruct.datasize);
if (result == kIOReturnSuccess) {
if (val -> datasize > 0) {
if (val -> datatype == ('f' << 24 | 'l' << 16 | 't' << 8 )) { //bit shifting to from 32bit operation associated with the ASCII charecters'f', 'l', and 't', sets datatype field.
double temp = *(double *)val -> data;
return temp;
}
}
}
return 0.0;
}
Which I am then then calling the functions from this file in a swift file and converting the values to Fahrenheit but no data is being printed in my console:
import IOKit
public class getTemperature {
public struct SMCVal_t {
var datasize: UInt32
var datatype: UInt32
var data: (UInt8, UInt8, UInt8, UInt8, UInt8, UInt8, UInt8, UInt8)
}
@_silgen_name("openSMC")
func openSMC() -> kern_return_t
@_silgen_name("closeSMC")
func closeSMC() -> kern_return_t
@_silgen_name("readSMC")
func readSMC(key: UnsafePointer<CChar>?,val: UnsafeMutablePointer<SMCVal_t>) -> kern_return_t
func convertAndPrintTempValue(key:UnsafePointer<CChar>?,scale: Character, showTemp: Bool ) -> kern_return_t {
let openSM = openSMC()
guard openSM == 0 else {
print("Failed to open SMC: \(openSM)")
return kern_return_t()
}
let closeSM = closeSMC()
guard closeSM == 0 else {
print("could not close SMC: \(closeSM)")
return IOServiceClose(conn)
}
func convertAndPrint(val: SMCVal_t) -> Double {
if val.datatype == (UInt32("f".utf8.first!) << 24 | UInt32("l".utf8.first!) << 16 | UInt32("t".utf8.first!) << 8) {
let extractedTemp = Double(val.data.0)
return( extractedTemp * 9.0 / 5.0 + 32.0 )
}
return 0.0
}
let smcValue = SMCVal_t(datasize: 0, datatype: 0, data: (0,0,0,0,0,0,0,0))
let convertedVal = convertAndPrint(val: smcValue)
print("Temperarure:\(convertedVal)F°")
return kern_return_t()
}
}
I know this is a lot but I am honestly looking for any tips to fill in any gaps in my knowledge for anyone who's built a similar application meant to extract any sort of data from Mac hardware.
