uclibc-ng/libc/misc/dirent/opendir.c

/*
 * Copyright (C) 2000-2006 Erik Andersen <andersen@uclibc.org>
 *
 * Licensed under the LGPL v2.1, see the file COPYING.LIB in this tarball.
 */

#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/dir.h>
#include <sys/stat.h>
#include "dirstream.h"

libc_hidden_proto(opendir)
libc_hidden_proto(open)
libc_hidden_proto(fcntl)
libc_hidden_proto(close)
libc_hidden_proto(stat)
libc_hidden_proto(fstat)

/* opendir just makes an open() call - it return NULL if it fails
 * (open sets errno), otherwise it returns a DIR * pointer.
 */
DIR *opendir(const char *name)
{
	int fd;
	struct stat statbuf;
	DIR *ptr;

#ifndef O_DIRECTORY
	/* O_DIRECTORY is linux specific and has been around since like 2.1.x */
	if (stat(name, &statbuf))
		return NULL;
	if (!S_ISDIR(statbuf.st_mode)) {
		__set_errno(ENOTDIR);
		return NULL;
	}
# define O_DIRECTORY 0
#endif
	if ((fd = open(name, O_RDONLY|O_NDELAY|O_DIRECTORY)) < 0)
		return NULL;

	/* Note: we should check to make sure that between the stat() and open()
	 * call, 'name' didnt change on us, but that's only if O_DIRECTORY isnt
	 * defined and since Linux has supported it for like ever, i'm not going
	 * to worry about it right now (if ever). */
	if (fstat(fd, &statbuf) < 0)
		goto close_and_ret;

	/* According to POSIX, directory streams should be closed when
	 * exec. From "Anna Pluzhnikov" <besp@midway.uchicago.edu>.
	 */
	if (fcntl(fd, F_SETFD, FD_CLOEXEC) < 0) {
		int saved_errno;
close_and_ret:
		saved_errno = errno;
		close(fd);
		__set_errno(saved_errno);
		return NULL;
	}
	if (!(ptr = malloc(sizeof(*ptr))))
		goto nomem_close_and_ret;

	memset(ptr, '\0', sizeof(DIR));
	ptr->dd_fd = fd;

	ptr->dd_max = statbuf.st_blksize;
	if (ptr->dd_max < 512)
		ptr->dd_max = 512;

	if (!(ptr->dd_buf = calloc(1, ptr->dd_max))) {
		free(ptr);
nomem_close_and_ret:
		close(fd);
		__set_errno(ENOMEM);
		return NULL;
	}
	__pthread_mutex_init(&(ptr->dd_lock), NULL);
	return ptr;
}
libc_hidden_def(opendir)