stages/grub2: add support for terminal, serial and timeout config

This commit adds options to the org.osbuild.grub2 stage to configure
terminal input and output, serial console and timeout.

The functionality and configuration schema is the same as in the legacy
grub2 stage.

stages/org.osbuild.grub2

@@ -113,6 +113,13 @@ SCHEMA = """
         ]
       }
     }
+  },
+  "terminal": {
+    "description": "Terminal device",
+    "type": "array",
+    "items": {
+      "type": "string"
+    }
   }
 },
 "properties": {
@@ -191,6 +198,29 @@ SCHEMA = """
     "description": "Include support for fallback counting",
     "type": "boolean",
     "default": false
+  },
+  "config": {
+    "description": "Configuration options for grub itself",
+    "type": "object",
+    "additionalProperties": false,
+    "properties": {
+      "terminal_input": {
+         "$ref": "#/definitions/terminal"
+      },
+      "terminal_output": {
+         "$ref": "#/definitions/terminal"
+      },
+      "timeout": {
+        "description": "Timeout in seconds",
+        "type": "integer",
+        "minimum": 0,
+        "default": 0
+      },
+      "serial": {
+        "description": "The command to configure the serial console",
+        "type": "string"
+      }
+    }
   }
 }
 """
@@ -203,7 +233,7 @@ SCHEMA = """
 #   - $ignition: configuration for ignition, if support for ignition
 #     is enabled
 GRUB_CFG_TEMPLATE = """
-set timeout=0
+set timeout=${timeout}
 
 # load the grubenv file
 load_env
@@ -226,7 +256,7 @@ set boot=$${root}
 function load_video {
   insmod all_video
 }
-${features}
+${features}${serial}${terminal_input}${terminal_output}
 blscfg
 """
 
@@ -340,6 +370,11 @@ class GrubConfig:
         self.path = "boot/grub2/grub.cfg"
         self.ignition = False
         self.greenboot = False
+        self.kernel_opts = ""
+        self.serial = ""
+        self.terminal_input = None
+        self.terminal_output = None
+        self.timeout = 0
 
     @property
     def grubfs(self):
@@ -358,6 +393,19 @@ class GrubConfig:
     def grub_home(self):
         return "/" if self.separate_boot else "/boot/"
 
+    def make_terminal_config(self, terminal):
+        config = getattr(self, terminal)
+        if not config:
+            return {}
+
+        val = (
+            "\n" +
+            terminal +
+            " " +
+            " ".join(config)
+        )
+        return {terminal: val}
+
     def write(self, tree):
         """Write the grub config to `tree` at `self.path`"""
         path = os.path.join(tree, self.path)
@@ -382,10 +430,17 @@ class GrubConfig:
 
         # configuration options for the main template
         config = {
+            "timeout": self.timeout,
             "search": type2opt[fs_type] + " " + fs_id,
             "features": features,
         }
 
+        if self.serial:
+            config["serial"] = "\n" + self.serial
+
+        config.update(self.make_terminal_config("terminal_input"))
+        config.update(self.make_terminal_config("terminal_output"))
+
         tplt = string.Template(GRUB_CFG_TEMPLATE)
         data = tplt.safe_substitute(config)
 
@@ -408,6 +463,28 @@ class GrubConfig:
         with open(os.path.join(tree, path), "w") as cfg:
             cfg.write(data)
 
+    def defaults(self):
+        # NB: The "GRUB_CMDLINE_LINUX" variable contains the kernel command
+        # line but without the `root=` part, thus we just use `kernel_opts`.
+        data = (
+            f'GRUB_CMDLINE_LINUX="{self.kernel_opts}"\n'
+            f"GRUB_TIMEOUT={self.timeout}\n"
+            "GRUB_ENABLE_BLSCFG=true\n"
+        )
+
+        if self.serial:
+            data += f'GRUB_SERIAL_COMMAND="{self.serial}"\n'
+
+        if self.terminal_input:
+            val = " ".join(self.terminal_input)
+            data += f'GRUB_TERMINAL_INPUT="{val}"\n'
+
+        if self.terminal_output:
+            val = " ".join(self.terminal_output)
+            data += f'GRUB_TERMINAL_OUTPUT="{val}"\n'
+
+        return data
+
 
 #pylint: disable=too-many-statements
 def main(tree, options):
@@ -419,6 +496,7 @@ def main(tree, options):
     write_defaults = options.get("write_defaults", True)
     ignition = options.get("ignition", False)
     saved_entry = options.get("saved_entry")
+    cfg = options.get("config", {})
 
     # backwards compatibility
     if not root_fs:
@@ -442,16 +520,17 @@ def main(tree, options):
     config = GrubConfig(root_fs, boot_fs)
     config.ignition = ignition
     config.greenboot = options.get("greenboot", False)
+    config.kernel_opts = kernel_opts
+    config.serial = cfg.get("serial")
+    config.terminal_input = cfg.get("terminal_input")
+    config.terminal_output = cfg.get("terminal_output")
+    config.timeout = cfg.get("timeout", 0)
 
     # Create the configuration file that determines how grub.cfg is generated.
     if write_defaults:
         os.makedirs(f"{tree}/etc/default", exist_ok=True)
         with open(f"{tree}/etc/default/grub", "w") as default:
-            # NB: The "GRUB_CMDLINE_LINUX" variable contains the kernel command
-            # line but without the `root=` part, thus we just use `kernel_opts`.
-            default.write(f'GRUB_CMDLINE_LINUX="{kernel_opts}"\n'
-                          "GRUB_TIMEOUT=0\n"
-                          "GRUB_ENABLE_BLSCFG=true\n")
+            default.write(config.defaults())
 
     os.makedirs(f"{tree}/boot/grub2", exist_ok=True)
     grubenv = f"{tree}/boot/grub2/grubenv"

test/data/stages/grub2/b.json

@@ -356,6 +356,18 @@
               "vendor": "fedora",
               "install": true,
               "unified": true
+            },
+            "config": {
+              "timeout": 10,
+              "terminal_input": [
+                "serial",
+                "console"
+              ],
+              "terminal_output": [
+                "serial",
+                "console"
+              ],
+              "serial": "serial --speed=115200 --unit=0 --word=8 --parity=no --stop=1"
             }
           }
         }

test/data/stages/grub2/b.mpp.json

@@ -22,6 +22,18 @@
               "vendor": "fedora",
               "install": true,
               "unified": true
+            },
+            "config": {
+              "timeout": 10,
+              "terminal_input": [
+                "serial",
+                "console"
+              ],
+              "terminal_output": [
+                "serial",
+                "console"
+              ],
+              "serial": "serial --speed=115200 --unit=0 --word=8 --parity=no --stop=1"
             }
           }
         }