HelenOS sources

root/uspace/lib/c/generic/dirent.c

DEFINITIONS

1. opendir
2. readdir
3. rewinddir
4. closedir

/*
 * Copyright (c) 2008 Jakub Jermar
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/** @addtogroup libc
 * @{
 */
/** @file
 */

#include <vfs/vfs.h>
#include <stdlib.h>
#include <dirent.h>
#include <stddef.h>
#include <errno.h>
#include <assert.h>
#include <string.h>

struct __dirstream {
        int fd;
        struct dirent res;
        aoff64_t pos;
};

/** Open directory.
 *
 * @param dirname Directory pathname
 *
 * @return Non-NULL pointer on success. On error returns @c NULL and sets errno.
 */
DIR *opendir(const char *dirname)
{
        DIR *dirp = malloc(sizeof(DIR));
        if (!dirp) {
                errno = ENOMEM;
                return NULL;
        }

        int fd;
        errno_t rc = vfs_lookup(dirname, WALK_DIRECTORY, &fd);
        if (rc != EOK) {
                free(dirp);
                errno = rc;
                return NULL;
        }

        rc = vfs_open(fd, MODE_READ);
        if (rc != EOK) {
                free(dirp);
                vfs_put(fd);
                errno = rc;
                return NULL;
        }

        dirp->fd = fd;
        dirp->pos = 0;
        return dirp;
}

/** Read directory entry.
 *
 * @param dirp Open directory
 * @return Non-NULL pointer to directory entry on success. On error returns
 *         @c NULL and sets errno.
 */
struct dirent *readdir(DIR *dirp)
{
        errno_t rc;
        ssize_t len = 0;

        rc = vfs_read_short(dirp->fd, dirp->pos, dirp->res.d_name,
            sizeof(dirp->res.d_name), &len);
        if (rc != EOK) {
                errno = rc;
                return NULL;
        }

        assert(strnlen(dirp->res.d_name, sizeof(dirp->res.d_name)) < sizeof(dirp->res.d_name));

        dirp->pos += len;

        return &dirp->res;
}

/** Rewind directory position to the beginning.
 *
 * @param dirp Open directory
 */
void rewinddir(DIR *dirp)
{
        dirp->pos = 0;
}

/** Close directory.
 *
 * @param dirp Open directory
 * @return 0 on success. On error returns -1 and sets errno.
 */
int closedir(DIR *dirp)
{
        errno_t rc = vfs_put(dirp->fd);
        free(dirp);

        if (rc == EOK) {
                return 0;
        } else {
                errno = rc;
                return -1;
        }
}

/** @}
 */