[process-reboot-cause]Address the issue: Incorrect reboot cause returned when warm reboot follows a hardware caused reboot

files/image_config/process-reboot-cause/process-reboot-cause

@@ -11,6 +11,7 @@ try:
     import pwd
     import sys
     import syslog
+    import re
 except ImportError as err:
     raise ImportError("%s - required module not found" % str(err))
 
@@ -22,6 +23,9 @@ REBOOT_CAUSE_DIR = "/host/reboot-cause/"
 REBOOT_CAUSE_FILE = REBOOT_CAUSE_DIR + "reboot-cause.txt"
 PREVIOUS_REBOOT_CAUSE_FILE = REBOOT_CAUSE_DIR + "previous-reboot-cause.txt"
 FIRST_BOOT_PLATFORM_FILE = "/tmp/notify_firstboot_to_platform"
+REBOOT_CAUSE_KEXEC = "/proc/cmdline"
+# The following SONIC_BOOT_TYPEs come from the warm/fast reboot script which is in sonic-utilities
+REBOOT_CAUSE_KEXEC_PATTERN = ".*SONIC_BOOT_TYPE=(fast-reboot|warm|fastfast)$"
 
 UNKNOWN_REBOOT_CAUSE = "Unknown"
 
@@ -47,6 +51,16 @@ def log_error(msg):
 
 
 # ============================= Functions =============================
+def is_warmfast_reboot_from_proc_cmdline():
+    if os.path.isfile(REBOOT_CAUSE_KEXEC):
+        cause_file = open(REBOOT_CAUSE_KEXEC, "r")
+        cause_file_kexec = cause_file.readline()
+        m = re.match(REBOOT_CAUSE_KEXEC_PATTERN, cause_file_kexec)
+        if m and m.group(1):
+            # the pattern matched so it's a fast/warm reboot
+            return True
+    return False
+
 
 def main():
     log_info("Starting up...")
@@ -73,31 +87,49 @@ def main():
     try:
         import sonic_platform
 
-        # Check if the previous reboot was caused by hardware
-        platform = sonic_platform.platform.Platform()
-
-        chassis = platform.get_chassis()
+        proc_cmdline_reboot_cause = None
 
-        hardware_reboot_cause, optional_details = chassis.get_reboot_cause()
-
-        if hardware_reboot_cause == chassis.REBOOT_CAUSE_NON_HARDWARE:
-            # The reboot was not caused by hardware. If there is a REBOOT_CAUSE_FILE, it will
-            # contain any software-related reboot info. We will use it as the previous cause.
+        # 1. Check if the previous reboot was warm/fast reboot by testing whether there is "fast|fastfast|warm" in /proc/cmdline
+        #    If yes, the content of /hosts/reboot-cause/reboot-cause.txt will be treated as the reboot cause
+        if is_warmfast_reboot_from_proc_cmdline():
             if os.path.isfile(REBOOT_CAUSE_FILE):
                 cause_file = open(REBOOT_CAUSE_FILE, "r")
-                previous_reboot_cause = cause_file.readline().rstrip('\n')
+                proc_cmdline_reboot_cause = cause_file.readline().rstrip('\n')
                 cause_file.close()
-            # If it is FirstTime Boot and previous_reboot_cause is unknown
-            # and hardware_reboot cause is non_hardware then
-            # Update the reboot cause as required
-            if os.path.isfile(FIRST_BOOT_PLATFORM_FILE):
-                if (previous_reboot_cause == UNKNOWN_REBOOT_CAUSE):
-                     previous_reboot_cause = UNKNOWN_REBOOT_CAUSE
-                os.remove(FIRST_BOOT_PLATFORM_FILE)
-        elif hardware_reboot_cause == chassis.REBOOT_CAUSE_HARDWARE_OTHER:
-            previous_reboot_cause = "{} ({})".format(hardware_reboot_cause, optional_details)
+            else:
+                # /proc/cmdline says it's a warm/fast reboot but /host/reboot-cause.txt doesn't exist.
+                # report an error.
+                log_error("/proc/cmdline indicates a fast/warm reboot but {} doesn't exist".format(REBOOT_CAUSE_DIR))
+
+        if proc_cmdline_reboot_cause is not None:
+            previous_reboot_cause = proc_cmdline_reboot_cause
         else:
-            previous_reboot_cause = hardware_reboot_cause
+            # 2. Check if the previous reboot was caused by hardware
+            #    If yes, the hardware reboot cause will be treated as teh reboot cause
+            platform = sonic_platform.platform.Platform()
+
+            chassis = platform.get_chassis()
+
+            hardware_reboot_cause, optional_details = chassis.get_reboot_cause()
+
+            if hardware_reboot_cause == chassis.REBOOT_CAUSE_NON_HARDWARE:
+                # The reboot was not caused by hardware. If there is a REBOOT_CAUSE_FILE, it will
+                # contain any software-related reboot info. We will use it as the previous cause.
+                if os.path.isfile(REBOOT_CAUSE_FILE):
+                    cause_file = open(REBOOT_CAUSE_FILE, "r")
+                    previous_reboot_cause = cause_file.readline().rstrip('\n')
+                    cause_file.close()
+                # If it is FirstTime Boot and previous_reboot_cause is unknown
+                # and hardware_reboot cause is non_hardware then
+                # Update the reboot cause as required
+                if os.path.isfile(FIRST_BOOT_PLATFORM_FILE):
+                    if (previous_reboot_cause == UNKNOWN_REBOOT_CAUSE):
+                        previous_reboot_cause = UNKNOWN_REBOOT_CAUSE
+                    os.remove(FIRST_BOOT_PLATFORM_FILE)
+            elif hardware_reboot_cause == chassis.REBOOT_CAUSE_HARDWARE_OTHER:
+                previous_reboot_cause = "{} ({})".format(hardware_reboot_cause, optional_details)
+            else:
+                previous_reboot_cause = hardware_reboot_cause
     except ImportError as err:
         log_warning("sonic_platform package not installed. Unable to detect hardware reboot causes.")