banan-os/libc/dirent.cpp

85 lines
1.4 KiB
C++

#include <dirent.h>
#include <errno.h>
#include <fcntl.h>
#include <stdlib.h>
#include <sys/syscall.h>
#include <unistd.h>
struct __DIR
{
int fd { -1 };
size_t entry_count { 0 };
size_t entry_index { 0 };
// FIXME: we should probably allocate entries dynamically
// based if syscall returns ENOBUFS
dirent entries[128];
};
int closedir(DIR* dirp)
{
if (dirp == nullptr || dirp->fd == -1)
{
errno = EBADF;
return -1;
}
close(dirp->fd);
free(dirp);
return 0;
}
int dirfd(DIR* dirp)
{
if (dirp == nullptr || dirp->fd == -1)
{
errno = EINVAL;
return -1;
}
return dirp->fd;
}
DIR* fdopendir(int fd)
{
DIR* dirp = (DIR*)malloc(sizeof(DIR));
if (dirp == nullptr)
return nullptr;
dirp->fd = fd;
dirp->entry_count = 0;
dirp->entry_index = 0;
return dirp;
}
DIR* opendir(const char* dirname)
{
int fd = open(dirname, O_RDONLY);
if (fd == -1)
return nullptr;
return fdopendir(fd);
}
struct dirent* readdir(DIR* dirp)
{
if (dirp == nullptr || dirp->fd == -1)
{
errno = EBADF;
return nullptr;
}
dirp->entry_index++;
if (dirp->entry_index < dirp->entry_count)
return &dirp->entries[dirp->entry_index];
long entry_count = syscall(SYS_READ_DIR, dirp->fd, dirp->entries, sizeof(dirp->entries) / sizeof(dirp->entries[0]));
if (entry_count <= 0)
return nullptr;
dirp->entry_count = entry_count;
dirp->entry_index = 0;
return &dirp->entries[0];
}