dirent.h

  1/* SPDX-License-Identifier: LGPL-2.1 OR MIT */
  2/*
  3 * Directory access for NOLIBC
  4 * Copyright (C) 2025 Thomas Weißschuh <linux@weissschuh.net>
  5 */
  6
  7/* make sure to include all global symbols */
  8#include "nolibc.h"
  9
 10#ifndef _NOLIBC_DIRENT_H
 11#define _NOLIBC_DIRENT_H
 12
 13#include "compiler.h"
 14#include "stdint.h"
 15#include "types.h"
 16#include "fcntl.h"
 17
 18#include <linux/limits.h>
 19
 20struct dirent {
 21	ino_t	d_ino;
 22	char	d_name[NAME_MAX + 1];
 23};
 24
 25/* See comment of FILE in stdio.h */
 26typedef struct {
 27	char dummy[1];
 28} DIR;
 29
 30static __attribute__((unused))
 31DIR *fdopendir(int fd)
 32{
 33	if (fd < 0) {
 34		SET_ERRNO(EBADF);
 35		return NULL;
 36	}
 37	return (DIR *)(intptr_t)~fd;
 38}
 39
 40static __attribute__((unused))
 41DIR *opendir(const char *name)
 42{
 43	int fd;
 44
 45	fd = open(name, O_RDONLY);
 46	if (fd == -1)
 47		return NULL;
 48	return fdopendir(fd);
 49}
 50
 51static __attribute__((unused))
 52int closedir(DIR *dirp)
 53{
 54	intptr_t i = (intptr_t)dirp;
 55
 56	if (i >= 0) {
 57		SET_ERRNO(EBADF);
 58		return -1;
 59	}
 60	return close(~i);
 61}
 62
 63static __attribute__((unused))
 64int readdir_r(DIR *dirp, struct dirent *entry, struct dirent **result)
 65{
 66	char buf[sizeof(struct linux_dirent64) + NAME_MAX + 1] __nolibc_aligned_as(struct linux_dirent64);
 67	struct linux_dirent64 *ldir = (void *)buf;
 68	intptr_t i = (intptr_t)dirp;
 69	int fd, ret;
 70
 71	if (i >= 0)
 72		return EBADF;
 73
 74	fd = ~i;
 75
 76	ret = sys_getdents64(fd, ldir, sizeof(buf));
 77	if (ret < 0)
 78		return -ret;
 79	if (ret == 0) {
 80		*result = NULL;
 81		return 0;
 82	}
 83
 84	/*
 85	 * getdents64() returns as many entries as fit the buffer.
 86	 * readdir() can only return one entry at a time.
 87	 * Make sure the non-returned ones are not skipped.
 88	 */
 89	ret = sys_lseek(fd, ldir->d_off, SEEK_SET);
 90	if (ret < 0)
 91		return -ret;
 92
 93	entry->d_ino = ldir->d_ino;
 94	/* the destination should always be big enough */
 95	strlcpy(entry->d_name, ldir->d_name, sizeof(entry->d_name));
 96	*result = entry;
 97	return 0;
 98}
 99
100#endif /* _NOLIBC_DIRENT_H */