#include "ELF.h"
#include "Log.h"
#include "fs/VFS.h"
#include "memory/MemoryManager.h"
#include "sys/Syscall.h"
#include "thread/Scheduler.h"
#include "thread/ThreadImage.h"
#include <bits/modes.h>
#include <luna/CString.h>
#include <luna/ScopeGuard.h>

Result<u64> sys_exec(Registers* regs, SyscallArgs args)
{
    auto path = TRY(MemoryManager::strdup_from_user(args[0]));

    auto inode = TRY(VFS::resolve_path(path.chars()));

    // Not executable
    if ((inode->mode() & S_IXUSR) != S_IXUSR) return err(EACCES);

    kinfoln("exec: attempting to replace current image with %s", path.chars());

    auto current = Scheduler::current();

    auto image = TRY(ThreadImage::try_load_from_elf(inode));

    // From now on, nothing should fail.

    kinfoln("exec: image load ok, will now replace existing process image");

    // FIXME: Close only O_CLOEXEC file descriptors.
    for (int i = 0; i < FD_MAX; i++) { current->fd_table[i] = {}; }

    MMU::delete_userspace_page_directory(current->directory);

    image->apply(current);

    MMU::switch_page_directory(current->directory);

    memcpy(regs, &current->regs, sizeof(*regs));

    kinfoln("exec: done");

    return 0;
}