From 738f9de9a9e30032183f59416af5695b15ed39fc Mon Sep 17 00:00:00 2001
From: Conrad Pankoff <deoxxa@fknsrs.biz>
Date: Tue, 4 Jun 2019 20:54:27 +1000
Subject: [PATCH] Kernel: Add KParams class for accessing kernel cmdline
 parameters (#188)

---
 Kernel/KParams.cpp | 34 ++++++++++++++++++++++++++++++++++
 Kernel/KParams.h   | 19 +++++++++++++++++++
 Kernel/Makefile    |  1 +
 Kernel/grub.cfg    |  2 +-
 Kernel/init.cpp    |  6 ++++--
 5 files changed, 59 insertions(+), 3 deletions(-)
 create mode 100644 Kernel/KParams.cpp
 create mode 100644 Kernel/KParams.h

diff --git a/Kernel/KParams.cpp b/Kernel/KParams.cpp
new file mode 100644
index 00000000000..37e3ee72751
--- /dev/null
+++ b/Kernel/KParams.cpp
@@ -0,0 +1,34 @@
+#include <Kernel/KParams.h>
+
+static KParams* s_the;
+
+KParams& KParams::the()
+{
+    return *s_the;
+}
+
+KParams::KParams(const String& cmdline)
+    : m_cmdline(cmdline)
+{
+    s_the = this;
+
+    for (auto str : m_cmdline.split(' ')) {
+        auto pair = str.split_limit('=', 2);
+
+        if (pair.size() == 1) {
+            m_params.set(pair[0], "");
+        } else {
+            m_params.set(pair[0], pair[1]);
+        }
+    }
+}
+
+String KParams::get(const String& key) const
+{
+    return m_params.get(key);
+}
+
+bool KParams::has(const String& key) const
+{
+    return m_params.contains(key);
+}
diff --git a/Kernel/KParams.h b/Kernel/KParams.h
new file mode 100644
index 00000000000..51da17006a7
--- /dev/null
+++ b/Kernel/KParams.h
@@ -0,0 +1,19 @@
+#pragma once
+
+#include <AK/AKString.h>
+#include <AK/HashMap.h>
+
+class KParams {
+    AK_MAKE_ETERNAL
+public:
+    static KParams& the();
+
+    KParams(const String& cmdline);
+
+    const String& cmdline() const { return m_cmdline; }
+    String get(const String& key) const;
+    bool has(const String& key) const;
+private:
+    String m_cmdline;
+    HashMap<String, String> m_params;
+};
diff --git a/Kernel/Makefile b/Kernel/Makefile
index ac124001d73..3479d8eed2e 100644
--- a/Kernel/Makefile
+++ b/Kernel/Makefile
@@ -32,6 +32,7 @@ KERNEL_OBJS = \
        Scheduler.o \
        DoubleBuffer.o \
        KSyms.o \
+       KParams.o \
        SharedMemory.o \
        FileSystem/DevPtsFS.o \
        Devices/BXVGADevice.o \
diff --git a/Kernel/grub.cfg b/Kernel/grub.cfg
index be638e928e8..31a55e9aff1 100644
--- a/Kernel/grub.cfg
+++ b/Kernel/grub.cfg
@@ -2,5 +2,5 @@ timeout=0
 
 menuentry 'Serenity' {
   root=hd0,1
-  multiboot /boot/kernel Hello from grub!
+  multiboot /boot/kernel root=hd0,1
 }
diff --git a/Kernel/init.cpp b/Kernel/init.cpp
index 098e81c9d1a..7939bd86700 100644
--- a/Kernel/init.cpp
+++ b/Kernel/init.cpp
@@ -28,6 +28,7 @@
 #include <Kernel/Net/NetworkTask.h>
 #include <Kernel/Devices/DebugLogDevice.h>
 #include <Kernel/Multiboot.h>
+#include <Kernel/KParams.h>
 
 //#define STRESS_TEST_SPAWNING
 
@@ -123,13 +124,14 @@ multiboot_info_t* multiboot_info_ptr;
 
 extern "C" [[noreturn]] void init()
 {
-    kprintf("Kernel command line: '%s'\n", multiboot_info_ptr->cmdline);
-
     sse_init();
 
     kmalloc_init();
     init_ksyms();
 
+    // must come after kmalloc_init because we use AK_MAKE_ETERNAL in KParams
+    new KParams(String(reinterpret_cast<const char*>(multiboot_info_ptr->cmdline)));
+
     vfs = new VFS;
     dev_debuglog = new DebugLogDevice;