From 96ff1a24a7474b91c44a3dcd6f3abf3ec0542191 Mon Sep 17 00:00:00 2001
From: Ada Christine <adachristine18@gmail.com>
Date: Tue, 13 Feb 2024 01:04:02 +0000
Subject: reorganize a bit

---
 kjarna/efi/runtime.c | 195 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 195 insertions(+)
 create mode 100644 kjarna/efi/runtime.c

(limited to 'kjarna/efi/runtime.c')

diff --git a/kjarna/efi/runtime.c b/kjarna/efi/runtime.c
new file mode 100644
index 0000000..5f2e7e1
--- /dev/null
+++ b/kjarna/efi/runtime.c
@@ -0,0 +1,195 @@
+#include <posix/unistd.h>
+#include <posix/fcntl.h>
+#include <kjarna/interface.h>
+#include <libc/string.h>
+#include <lib/elf.h>
+
+#include "kjarna_efi.h"
+
+#include <efi/error.h>
+
+struct runtime_buffer
+{
+	char *base;
+	size_t length;
+};
+
+static ssize_t read_ehdr(int fd, Elf64_Ehdr *ehdr)
+{
+	ssize_t result;
+
+	if (efi_lseek(fd, 0, SEEK_SET) == -1)
+	{
+		return -1;
+	}
+	else if ((result = efi_read(fd, ehdr, sizeof(*ehdr))) == -1)
+	{
+		return -1;
+	}
+	else if (!elf64_validate(ehdr, ET_DYN, EM_X86_64))
+	{
+		return -1;
+	}
+
+	return result;
+}
+
+static ssize_t read_phdrs(int fd, Elf64_Ehdr *ehdr, Elf64_Phdr *phdrs)
+{
+	if (efi_lseek(fd, ehdr->e_phoff, SEEK_SET) != -1)
+	{
+		return efi_read(fd, phdrs, ehdr->e_phnum * ehdr->e_phentsize);
+	}
+
+	return -1;
+}
+
+static void create_runtime_buffer(Elf64_Ehdr *ehdr, Elf64_Phdr *phdrs, struct runtime_buffer *buffer)
+{
+	buffer->length = elf64_size(ehdr, phdrs);
+	buffer->base = efi_mmap(nullptr, buffer->length, 0, 0, -1, 0);
+}
+
+static ssize_t load_segment(int fd, Elf64_Phdr *phdr, char *buffer)
+{
+	if (efi_lseek(fd, phdr->p_offset, SEEK_SET) == -1)
+	{
+		return -1;
+	}
+
+	int result = efi_read(fd, &buffer[phdr->p_offset], phdr->p_filesz);
+
+	if (result > 0 && phdr->p_memsz > phdr->p_filesz)
+	{
+		memset(&buffer[phdr->p_offset + phdr->p_filesz], 0, phdr->p_memsz - phdr->p_filesz);
+	}
+	
+	return result;
+}
+
+static ssize_t load_segments(int fd, Elf64_Ehdr *ehdr, Elf64_Phdr *phdrs, char *buffer)
+{
+	int i;
+
+	for (i = 0; i < ehdr->e_phnum; i++)
+	{
+		if (phdrs[i].p_type != PT_LOAD)
+		{
+			continue;
+		}
+
+		if (load_segment(fd, &phdrs[i], buffer) == -1)
+		{
+			return -1;
+		}
+	}
+
+	return i;
+}
+
+static struct runtime_buffer load_runtime(void)
+{
+	const char *runtime_entry_path = "\\adasoft\\sophia\\efi.os";
+
+	int runtime_fd;
+
+	struct runtime_buffer buffer = { nullptr, 0 };
+
+	if ((runtime_fd = efi_open(runtime_entry_path, O_RDONLY, 0)) == -1)
+	{
+		return buffer;
+	}
+
+	Elf64_Ehdr ehdr;
+
+	if (read_ehdr(runtime_fd, &ehdr) == -1)
+	{
+		return buffer;
+	}
+	
+	Elf64_Phdr *phdrs = efi_calloc_pool(ehdr.e_phnum, ehdr.e_phentsize);
+	
+	if (phdrs == nullptr)
+	{
+		return buffer;
+	}
+	else if(read_phdrs(runtime_fd, &ehdr, phdrs) != -1)
+	{
+		create_runtime_buffer(&ehdr, phdrs, &buffer);
+	}
+
+	if (buffer.base != nullptr && load_segments(runtime_fd, &ehdr, phdrs, buffer.base) == -1)
+	{
+		efi_munmap(buffer.base, buffer.length);
+		buffer.base = nullptr;
+	}
+
+	efi_free_pool(phdrs);
+
+	return buffer;
+}
+
+kjarna_runtime_entry_func *runtime_entry_addr(struct runtime_buffer *buffer)
+{
+	if (buffer->base == nullptr)
+	{
+		return nullptr;
+	}
+
+	Elf64_Ehdr *ehdr = (Elf64_Ehdr *)buffer->base;
+
+	return (kjarna_runtime_entry_func *)(buffer->base + ehdr->e_entry);
+}
+
+int runtime_start(void)
+{
+	struct kjarna_interface interface =
+	{
+		efi_open,
+		efi_close,
+		efi_lseek,
+		efi_read,
+		efi_write,
+		efi_mmap,
+		efi_munmap
+	};
+
+	struct kjarna_entry_params params =
+	{
+		&interface,
+		0,
+		nullptr,
+		nullptr
+	};
+
+	struct runtime_buffer buffer = load_runtime();
+
+	kjarna_runtime_entry_func *runtime_entry = nullptr;
+
+	if (buffer.base != nullptr)
+	{
+		runtime_entry = runtime_entry_addr(&buffer);
+	}
+
+	if (runtime_entry != nullptr)
+	{
+		runtime_entry(&params);
+	}
+
+	if (efi_munmap(buffer.base, buffer.length) == -1)
+	{
+		efi_write(STDOUT_FILENO, "failed unmap\r\n", -1);
+
+		if (efi_errno == EFI_NOT_FOUND)
+		{
+			efi_write(STDOUT_FILENO, "not found\r\n", -1);
+		}
+		else
+		{
+			efi_write(STDOUT_FILENO, "bad alignment?\r\n", -1);
+		}
+	}
+
+	return -1;
+}
+
-- 
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