Initial ramdisk support

- Create initrd library to support definitions and loading
- Allow tools compiled for the host machine to be built by wscript
- Create makerd tool to build initrd from manifest
- Move screenfont to initrd, so don't load framebuffer initially

src/tools/makerd/entry.cpp

@@ -0,0 +1,10 @@
+#include "entry.h"
+
+entry::entry(const std::string &in, const std::string &out) :
+	m_in(in), m_out(out), m_file(in, std::ios_base::binary)
+{
+	m_file.seekg(0, std::ios_base::end);
+	m_size = m_file.tellg();
+	m_file.seekg(0);
+}
+

src/tools/makerd/entry.h

@@ -0,0 +1,23 @@
+#pragma once
+#include <string>
+#include <fstream>
+
+class entry
+{
+public:
+	entry(const std::string &in, const std::string &out);
+
+	inline const std::string & in() const { return m_in; }
+	inline const std::string & out() const { return m_out; }
+	inline const std::ifstream & file() const { return m_file; }
+
+	inline size_t size() const { return m_size; }
+	inline bool good() const { return m_file.good(); }
+
+private:
+	std::string m_in;
+	std::string m_out;
+	std::ifstream m_file;
+	size_t m_size;
+};
+

src/tools/makerd/main.cpp

@@ -0,0 +1,115 @@
+#include <cstring>
+#include <fstream>
+#include <iostream>
+#include <string>
+#include <vector>
+#include "initrd/headers.h"
+#include "entry.h"
+
+int main(int argc, char **argv)
+{
+	if (argc != 3) {
+		std::cerr << "Usage: " << argv[0] << " <manifest> <output>" << std::endl;
+		return 1;
+	}
+
+	std::vector<entry> entries;
+	std::ifstream manifest(argv[1]);
+
+	size_t files_size = 0;
+	size_t names_size = 0;
+
+	while (manifest.good()) {
+		std::string in, out;
+
+		manifest >> in;
+		if (in.length() < 1)
+			continue;
+
+		manifest >> out;
+		if (in.front() == '#')
+			continue;
+
+		entries.emplace_back(in, out);
+		const entry &e = entries.back();
+
+		if (!e.good()) {
+			std::cerr << "Error reading file: " << in << std::endl;
+			return 1;
+		}
+
+		files_size += e.size();
+		names_size += out.length() + 1;
+	}
+
+	std::fstream out(argv[2],
+		std::ios_base::binary |
+		std::ios_base::trunc |
+		std::ios_base::out |
+		std::ios_base::in);
+
+	if (!out.good()) {
+		std::cerr << "Error opening file: " << argv[2] << std::endl;
+		return 1;
+	}
+
+	uint32_t total_length =
+		sizeof(initrd::disk_header) +
+		sizeof(initrd::file_header) * entries.size() +
+		names_size + files_size;
+
+	initrd::disk_header dheader;
+	std::memset(&dheader, 0, sizeof(dheader));
+
+	dheader.file_count = entries.size();
+	dheader.length = total_length;
+	out.write(reinterpret_cast<const char *>(&dheader), sizeof(dheader));
+
+	size_t name_offset =
+		sizeof(initrd::disk_header) +
+		sizeof(initrd::file_header) * entries.size();
+
+	size_t file_offset = name_offset + names_size;
+
+	for (auto &e : entries) {
+		initrd::file_header fheader;
+		std::memset(&fheader, 0, sizeof(fheader));
+		fheader.offset = file_offset;
+		fheader.length = e.size();
+		fheader.name_offset = name_offset;
+
+		out.write(
+			reinterpret_cast<const char *>(&fheader),
+			sizeof(fheader));
+
+		name_offset += e.out().length() + 1;
+		file_offset += e.size();
+	}
+
+	for (auto &e : entries) {
+		out.write(e.out().c_str(), e.out().length() + 1);
+	}
+
+	for (auto &e : entries) {
+		out << e.file().rdbuf();
+	}
+
+	char buffer[1024];
+	uint8_t checksum = 0;
+
+	out.seekg(0);
+	while (true) {
+		size_t n = out.readsome(&buffer[0], 1024);
+		if (n == 0 || out.eof()) break;
+
+		for (size_t i=0; i<n; ++i)
+			checksum += static_cast<uint8_t>(buffer[i]);
+	}
+
+	dheader.checksum = static_cast<uint8_t>(0 - checksum);
+	out.seekp(0);
+	out.write(reinterpret_cast<const char *>(&dheader), sizeof(dheader));
+
+	out.close();
+	return 0;
+}

src/tools/makerd/wscript

@@ -0,0 +1,15 @@
+
+def configure(ctx):
+    pass
+
+def build(bld):
+    sources = bld.path.ant_glob("**/*.cpp")
+
+    bld.program(
+        source = sources,
+        name = 'makerd',
+        target = 'makerd',
+        use = 'initrd',
+    )
+
+# vim: ft=python et