From bc613ad4089a3c67a93bdbf420255a1b7fe6fe22 Mon Sep 17 00:00:00 2001
From: Pritam Ghanghas <pghanghas@nebra.com>
Date: Mon, 6 Mar 2023 18:41:53 +0530
Subject: [PATCH] fix: Use proc/cpuinfo for hardware serial #496

---
 hw_diag/utilities/balena_migration.py |  8 +------
 hw_diag/utilities/hardware.py         | 30 +++++++++++++++++++++++++--
 hw_diag/utilities/system_metrics.py   | 17 ++++++++++-----
 3 files changed, 41 insertions(+), 14 deletions(-)

diff --git a/hw_diag/utilities/balena_migration.py b/hw_diag/utilities/balena_migration.py
index b97da565..fb99c8b6 100644
--- a/hw_diag/utilities/balena_migration.py
+++ b/hw_diag/utilities/balena_migration.py
@@ -3,7 +3,7 @@
 import subprocess
 import requests
 from hw_diag.utilities.osutils import balena_boot_partition
-from hw_diag.utilities.hardware import get_serial_number
+from hw_diag.utilities.hardware import fetch_serial_number
 from hw_diag.utilities.balena_supervisor import BalenaSupervisor
 from hm_pyhelper.logger import get_logger
 from typing import Dict, Union
@@ -101,12 +101,6 @@ def update_config(old_config) -> Union[Dict, None]:
     return new_config
 
 
-def fetch_serial_number() -> Union[str, None]:
-    diag = {}
-    get_serial_number(diag)
-    return diag.get("serial_number")
-
-
 def read_config() -> Dict:
     # read only mount would have been great but that isn't
     # possible as the fs is mounted in host os as rw.
diff --git a/hw_diag/utilities/hardware.py b/hw_diag/utilities/hardware.py
index 31ba9792..300bcbcd 100644
--- a/hw_diag/utilities/hardware.py
+++ b/hw_diag/utilities/hardware.py
@@ -1,6 +1,7 @@
 import re
 import dbus
 import psutil
+from typing import Union
 from urllib.parse import urlparse
 from hm_pyhelper.logger import get_logger
 from hm_pyhelper.miner_param import get_public_keys_rust
@@ -240,6 +241,12 @@ def detect_ecc(diagnostics):
             logging.error(e)
 
 
+def fetch_serial_number() -> Union[str, None]:
+    diag = {}
+    get_serial_number(diag)
+    return diag.get("serial_number")
+
+
 def get_serial_number(diagnostics):
     """
     input:
@@ -251,8 +258,13 @@ def get_serial_number(diagnostics):
     Writes the received value to the dictionary
     """
     try:
-        serial_number = open("/proc/device-tree/serial-number").readline() \
-            .rstrip('\x00')
+        cpuinfo = load_cpu_info()
+        serial_number = ""
+        if "serial" in cpuinfo:
+            serial_number = cpuinfo["serial"]
+        else:
+            serial_number = open("/proc/device-tree/serial-number").readline() \
+                .rstrip('\x00')
     except FileNotFoundError as e:
         raise e
     except PermissionError as e:
@@ -261,6 +273,20 @@ def get_serial_number(diagnostics):
     diagnostics["serial_number"] = serial_number
 
 
+def load_cpu_info() -> dict:
+    '''
+    returns /proc/cpuinfo as dict, keys are case-insensitive
+    '''
+    with open("/proc/cpuinfo", "r") as f:
+        cpuinfo = {}
+        lines = f.readlines()
+        for line in lines:
+            pair = line.split(":")
+            if len(pair) == 2:
+                cpuinfo[pair[0].strip().lower()] = pair[1].strip()
+        return cpuinfo
+
+
 @retry(Exception, tries=5, delay=5, max_delay=15, backoff=2, logger=logging)
 def lora_module_test():
     """
diff --git a/hw_diag/utilities/system_metrics.py b/hw_diag/utilities/system_metrics.py
index 5c802b86..f37785ed 100644
--- a/hw_diag/utilities/system_metrics.py
+++ b/hw_diag/utilities/system_metrics.py
@@ -1,6 +1,7 @@
 from typing import Dict, Any
 import logging
 import os
+from hw_diag.utilities.hardware import fetch_serial_number
 from hw_diag.utilities.balena_supervisor import BalenaSupervisor
 
 
@@ -48,11 +49,17 @@ def read_proc_file(file_path: str, default_value: str) -> Any:
 
 
 def get_serial_number() -> str:
+    '''
+    returns a valid serial number or empty string if none can
+    be determined. No exceptions.
+    '''
     try:
-        with open("/proc/device-tree/serial-number", 'r') as f:
-            return f.readline().rstrip('\x00')
+        serial_number = fetch_serial_number()
+        if not serial_number:
+            serial_number = ""
+        return serial_number
     except Exception as e:
-        log.warning(f"can't read serial number {e}")
+        log.error(f"failed to get serial number {e}")
         return ""
 
 
@@ -74,10 +81,10 @@ def get_network_statistics(interface_list=['wlan0', 'eth0']) -> Dict:
         stats[iface_name] = {
             "rx_errors": int(
                 read_proc_file(f"/sys/class/net/{iface_name}/statistics/rx_errors", "0")
-                ),
+            ),
             "tx_errors": int(
                 read_proc_file(f"/sys/class/net/{iface_name}/statistics/tx_errors", "0")
-                )
+            )
         }
     return stats