From 48e82a11a3ee34c80f765ab5b195574fdda1e787 Mon Sep 17 00:00:00 2001
From: Josh Holtrop <jholtrop@gmail.com>
Date: Wed, 13 Jul 2016 21:41:30 -0400
Subject: [PATCH] add initial System module

---
 src/core/System.cc | 31 +++++++++++++++++++++++++++++++
 src/core/System.h  | 12 ++++++++++++
 src/jes.cc         |  6 ++++++
 3 files changed, 49 insertions(+)
 create mode 100644 src/core/System.cc
 create mode 100644 src/core/System.h

diff --git a/src/core/System.cc b/src/core/System.cc
new file mode 100644
index 0000000..a4e6660
--- /dev/null
+++ b/src/core/System.cc
@@ -0,0 +1,31 @@
+#include "System.h"
+#include <stdio.h>
+#include <unistd.h>
+#include <sys/mman.h>
+
+long System::page_size;
+
+bool System::init()
+{
+    System::page_size = sysconf(_SC_PAGESIZE);
+    if ((System::page_size == 0) ||
+            (System::page_size > (2 * 1024 * 1024)) ||
+            ((System::page_size & (System::page_size - 1)) != 0))
+    {
+        printf("Unsupported page size detected: %ld\n", System::page_size);
+        return false;
+    }
+
+    return true;
+}
+
+void * System::alloc_pages(int num)
+{
+    return mmap(
+            NULL,
+            num * System::page_size,
+            PROT_READ | PROT_WRITE,
+            MAP_PRIVATE | MAP_ANONYMOUS,
+            -1,
+            0);
+}
diff --git a/src/core/System.h b/src/core/System.h
new file mode 100644
index 0000000..b0727b8
--- /dev/null
+++ b/src/core/System.h
@@ -0,0 +1,12 @@
+#ifndef SYSTEM_H
+#define SYSTEM_H
+
+class System
+{
+public:
+    static bool init();
+    static long page_size;
+    static void * alloc_pages(int num);
+};
+
+#endif
diff --git a/src/jes.cc b/src/jes.cc
index 2160bdc..b8dd61f 100644
--- a/src/jes.cc
+++ b/src/jes.cc
@@ -2,9 +2,15 @@
 #include "Window.h"
 #include "Runtime.h"
 #include <memory>
+#include "System.h"
 
 int main(int argc, char * argv[])
 {
+    if (!System::init())
+    {
+        return 1;
+    }
+
     Runtime::init(argv[0], APPNAME);
 
     std::shared_ptr<Buffer> b = std::make_shared<Buffer>();