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#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 "config.h"
#include <efi/error.h>
struct image_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_image_buffer(Elf64_Ehdr *ehdr, Elf64_Phdr *phdrs, struct image_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 image_buffer load_image(void)
{
const char *image_entry_path = SERVICE_FILE_PATH;
int image_fd;
struct image_buffer buffer = { nullptr, 0 };
if ((image_fd = efi_open(image_entry_path, O_RDONLY, 0)) == -1)
{
return buffer;
}
Elf64_Ehdr ehdr;
if (read_ehdr(image_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(image_fd, &ehdr, phdrs) != -1)
{
create_image_buffer(&ehdr, phdrs, &buffer);
}
if (buffer.base != nullptr && load_segments(image_fd, &ehdr, phdrs, buffer.base) == -1)
{
efi_munmap(buffer.base, buffer.length);
buffer.base = nullptr;
}
efi_close(image_fd);
efi_free_pool(phdrs);
return buffer;
}
kjarna_image_entry_func *image_entry_addr(struct image_buffer *buffer)
{
if (buffer->base == nullptr)
{
return nullptr;
}
Elf64_Ehdr *ehdr = (Elf64_Ehdr *)buffer->base;
return (kjarna_image_entry_func *)(buffer->base + ehdr->e_entry);
}
int image_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 image_buffer buffer = load_image();
kjarna_image_entry_func *image_entry = nullptr;
if (buffer.base != nullptr)
{
image_entry = image_entry_addr(&buffer);
}
if (image_entry != nullptr)
{
image_entry(¶ms);
}
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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