Luna/kernel/src/sys/getdents.cpp

#include "Pledge.h"
#include "fs/VFS.h"
#include "memory/MemoryManager.h"
#include "sys/Syscall.h"
#include "thread/Scheduler.h"
#include <bits/getdents.h>

Result<u64> sys_getdents(Registers*, SyscallArgs args)
{
    int fd = (int)args[0];
    luna_dirent* ent = (luna_dirent*)args[1];
    usize count = (usize)args[2];

    Thread* current = Scheduler::current();
    TRY(check_pledge(current, Promise::p_stdio));

    auto& descriptor = *TRY(current->resolve_fd(fd));

    if (descriptor.inode()->type() != VFS::InodeType::Directory) return err(ENOTDIR);

    usize nwrite = 0;
    while (nwrite < count)
    {
        VFS::DirectoryEntry entry;
        bool ok = descriptor.inode()->get(descriptor.offset).try_set_value(entry);
        if (!ok) break;

        descriptor.offset++;

        luna_dirent kent;
        kent.inode = entry.inode->metadata().inum;
        strlcpy(kent.name, entry.name.chars(), entry.name.length() + 1);

        if (!MemoryManager::copy_to_user_typed(ent, &kent)) return err(EFAULT);

        ent++;
        nwrite++;
    }

    return nwrite;
}