[action] [PR:237] [kdump-config] Update kdump default config with pre-defined value in /proc/cmdline (installer.conf) (#315)

#### Why I did it
Modify the hostcfgd to handle the kdump enabled to the CONFIG_DB when kdump is enabled by default in the platform installer.conf . Related PR for 202405 is: #236

### How I did it
Added a new method init_kdump_config_from_cmdline() in the KdumpCfg class to check the /proc/cmdline. If key "crashkernel=" exists in /proc/cmdline when system is up, this means that the kdump is enabled. init_kdump_config_from_cmdline() will update the kdump_defaults and CONFIG_DB when if the current config data are not matched the pre-defined data in the /proc/cmdline. This happens during a new image upgrade with the crashkernel is defined the platform installer.conf.

### How to verify it
1) install an image with predefine kdump enabled in the grub.conf.
2) execute the "config load_minigraph"
 - check it should not any error in the syslog
 - After the hostcfgd is running, execute "show kdump config" should show kdump is enabled. Output as below
 ```
admin@sonic:~$ show kdump config
Kdump administrative mode: Enabled
Kdump operational mode: Ready
Kdump memory reservation: 8G-:1G
Maximum number of Kdump files: 3
```

3) save config and reboot the system
4) show command should show the kdump is enabled and also there should not be any kdump/hostcfgd error log in syslog

### Which release branch to backport (provide reason below if selected)
- [ ] 201811
- [ ] 201911
- [ ] 202006
- [ ] 202012
- [ ] 202106
- [ ] 202111
- [ ] 202205
- [ ] 202211
- [ ] 202305
- [x] 202405

Author: mssonicbld

scripts/hostcfgd

@@ -1137,6 +1137,40 @@ class KdumpCfg(object):
                                 "memory": "0M-2G:256M,2G-4G:320M,4G-8G:384M,8G-:448M",
                                 "num_dumps": "3" }
 
+        # check if kdump is enabled by default with grub config
+        self.update_config_from_proc_cmdline = False
+        self.init_kdump_config_from_cmdline()
+
+    def init_kdump_config_from_cmdline(self):
+        # Update the kdump_defaults with value found /proc/cmdline if
+        # key "crashkernel=" is pre-defined in and /proc/cmdline (grub.conf)
+        if os.environ.get("HOSTCFGD_UNIT_TESTING") == "2":
+            modules_path = os.path.join(os.path.dirname(__file__), "..")
+            tests_path = os.path.join(modules_path, "tests")
+            cmdline = os.path.join(tests_path, "proc","cmdline")
+        else:
+            cmdline = "/proc/cmdline"
+
+        expected_str = ' crashkernel='
+        if os.path.exists(cmdline):
+            lines= [line.rstrip('\n') for line in open(cmdline)]
+            p = lines[0].find(expected_str)
+            if p == -1:
+                return
+            kdump_config = self.config_db.get_entry("KDUMP", "config") 
+            syslog.syslog(syslog.LOG_INFO, "kdump enabled is found in /proc/cmdline")
+            self.kdump_defaults["enabled"] = "true"
+            next_space = lines[0].find(" ", p+1)
+            if next_space == -1:
+                memory = lines[0][p+len(expected_str):]
+            else:
+                memory = lines[0][p+len(expected_str):next_space]
+            self.kdump_defaults["memory"] = memory
+            if not kdump_config or kdump_config.get("enabled") != self.kdump_defaults["enabled"] or kdump_config.get("memory") != self.kdump_defaults["memory"]:
+                self.update_config_from_proc_cmdline = True
+                syslog.syslog(syslog.LOG_INFO, "Update KDUMP config entry with data from /proc/cmdline")
+                self.config_db.mod_entry("KDUMP", "config", self.kdump_defaults)
+
     def load(self, kdump_table):
         """
         Set the KDUMP table in CFG DB to kdump_defaults if not set by the user
@@ -1155,6 +1189,10 @@ class KdumpCfg(object):
 
     def kdump_update(self, key, data):
         syslog.syslog(syslog.LOG_INFO, "Kdump global configuration update")
+        if self.update_config_from_proc_cmdline and os.environ.get("HOSTCFGD_UNIT_TESTING") != "2":
+            self.update_config_from_proc_cmdline = False
+            syslog.syslog(syslog.LOG_INFO, "Kdump is enabled by default with /proc/cmdline. Skip the first update")
+            return
         if key == "config":
             # Admin mode
             kdump_enabled = self.kdump_defaults["enabled"]

tests/hostcfgd/hostcfgd_test.py

@@ -236,6 +236,31 @@ def test_kdump_load(self):
 
             mocked_subprocess.check_call.assert_has_calls(expected, any_order=True)
 
+    def test_kdump_event_with_proc_cmdline(self):
+        os.environ["HOSTCFGD_UNIT_TESTING"] = "2"
+        MockConfigDb.set_config_db(HOSTCFG_DAEMON_CFG_DB)
+        daemon = hostcfgd.HostConfigDaemon()
+        default=daemon.kdumpCfg.kdump_defaults
+        daemon.kdumpCfg.load(default)
+        daemon.register_callbacks()
+        MockConfigDb.event_queue = [('KDUMP', 'config')]
+        with mock.patch('hostcfgd.subprocess') as mocked_subprocess:
+            popen_mock = mock.Mock()
+            attrs = {'communicate.return_value': ('output', 'error')}
+            popen_mock.configure_mock(**attrs)
+            mocked_subprocess.Popen.return_value = popen_mock
+            try:
+                daemon.start()
+            except TimeoutError:
+                pass
+            expected = [
+                call(['sonic-kdump-config', '--enable']),
+                call(['sonic-kdump-config', '--num_dumps', '3']),
+                call(['sonic-kdump-config', '--memory', '8G-:1G'])
+            ]
+            mocked_subprocess.check_call.assert_has_calls(expected, any_order=True)
+        os.environ["HOSTCFGD_UNIT_TESTING"] = ""
+        
     def test_devicemeta_event(self):
         """
         Test handling DEVICE_METADATA events.

tests/proc/cmdline

@@ -0,0 +1 @@
+BOOT_IMAGE=/image-202405.0-dirty-20250403.162657/boot/vmlinuz-6.1.0-22-2-amd64 root=UUID=bba2ec4f-9141-4069-a41e-230ecac4a5fb rw console=tty0 console=ttyS0,115200n8 quiet processor.max_cstate=1 amd_idle.max_cstate=0 sonic_fips=1 net.ifnames=0 biosdevname=0 loop=image-202405.0-dirty-20250403.162657/fs.squashfs loopfstype=squashfs systemd.unified_cgroup_hierarchy=0 apparmor=1 security=apparmor varlog_size=4096 usbcore.autosuspend=-1 amd_iommu=off pci=resource_alignment=48@00:03.1 crashkernel=8G-:1G