flb_utils: add code for getting the machineID on macOS.

src/flb_utils.c

@@ -46,6 +46,11 @@ extern struct flb_aws_error_reporter *error_reporter;
 #include <openssl/rand.h>
 #endif
 
+#ifdef FLB_SYSTEM_MACOS
+#include <CoreFoundation/CoreFoundation.h>
+#include <IOKit/IOKitLib.h>
+#endif
+
 /*
  * The following block descriptor describes the private use unicode character range
  * used for denoting invalid utf-8 fragments. Invalid fragment 0xCE would become
@@ -1416,6 +1421,46 @@ int flb_utils_get_machine_id(char **out_id, size_t *out_size)
         }
 
         *out_size = dwBufSize;
+        return 0;
+    }
+#elif defined (FLB_SYSTEM_MACOS)
+    bool bret;
+    CFStringRef serialNumber;
+    io_service_t platformExpert = IOServiceGetMatchingService(kIOMainPortDefault,
+        IOServiceMatching("IOPlatformExpertDevice"));
+
+    if (platformExpert) {
+        CFTypeRef serialNumberAsCFString =
+            IORegistryEntryCreateCFProperty(platformExpert,
+                                        CFSTR(kIOPlatformSerialNumberKey),
+                                        kCFAllocatorDefault, 0);
+        if (serialNumberAsCFString) {
+            serialNumber = (CFStringRef)serialNumberAsCFString;
+        }
+        else {
+            IOObjectRelease(platformExpert);
+            return -1;
+        }
+        IOObjectRelease(platformExpert);
+
+        *out_size = CFStringGetLength(serialNumber);
+        *out_id = flb_malloc(CFStringGetLength(serialNumber)+1);
+
+        if (*out_id == NULL) {
+            return -1;
+        }
+
+        bret = CFStringGetCString(serialNumber, *out_id,
+                                  CFStringGetLength(serialNumber)+1,
+                                  kCFStringEncodingUTF8);
+        CFRelease(serialNumber);
+
+        if (bret == false) {
+            flb_free(*out_size);
+            *out_size = 0;
+            return -1;
+        }
+
         return 0;
     }
 #endif