cmd/earlyinit: mount pseudo-filesystems

The proposal for merging both init programs was unanimously accepted, so this is set up here alongside devtmpfs.

Signed-off-by: Ophestra <cat@gensokyo.uk>

cmd/earlyinit/main.go

@@ -72,4 +72,40 @@ func main() {
 		}
 	}
 
+	// staying in rootfs, these are no longer used
+	must(os.Remove("/root"))
+	must(os.Remove("/init"))
+
+	must(os.Mkdir("/proc", 0))
+	mustSyscall("mount proc", Mount(
+		"proc",
+		"/proc",
+		"proc",
+		MS_NOSUID|MS_NOEXEC|MS_NODEV,
+		"hidepid=1",
+	))
+
+	must(os.Mkdir("/sys", 0))
+	mustSyscall("mount sysfs", Mount(
+		"sysfs",
+		"/sys",
+		"sysfs",
+		0,
+		"",
+	))
+
+}
+
+// mustSyscall calls [log.Fatalln] if err is non-nil.
+func mustSyscall(action string, err error) {
+	if err != nil {
+		log.Fatalln("cannot "+action+":", err)
+	}
+}
+
+// must calls [log.Fatal] with err if it is non-nil.
+func must(err error) {
+	if err != nil {
+		log.Fatal(err)
+	}
 }

internal/rosa/all.go

@@ -20,7 +20,7 @@ const (
 	LLVMRuntimes
 	LLVMClang
 
-	// EarlyInit is the Rosa OS initramfs init program.
+	// EarlyInit is the Rosa OS init program.
 	EarlyInit
 	// ImageSystem is the Rosa OS /system image.
 	ImageSystem