dirent.c

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/*-
 * Copyright (c) 1991 The Regents of the University of California.
 * All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Kenneth Almquist.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. 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.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the University of
 *      California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 REGENTS OR CONTRIBUTORS 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.
 */

#ifndef lint
static char sccsid[] = "@(#)dirent.c    5.1 (Berkeley) 3/7/91";
#endif /* not lint */

#include "shell.h"      /* definitions for pointer, NULL, DIRENT, and BSD */

#if ! DIRENT

#include <errno.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <dirent.h>

#ifndef S_ISDIR                         /* macro to test for directory file */
#define S_ISDIR(mode)           (((mode) & S_IFMT) == S_IFDIR)
#endif

#ifdef BSD

#ifdef __STDC__
int stat(char *, struct stat *);
#else
int stat();
#endif


/*
 * The BSD opendir routine doesn't check that what is being opened is a
 * directory, so we have to include the check in a wrapper routine.
 */

#undef opendir

DIR *
myopendir(dirname)
        char *dirname;                  /* name of directory */
        {
        struct stat statb;

        if (stat(dirname, &statb) != 0 || ! S_ISDIR(statb.st_mode)) {
                errno = ENOTDIR;
                return NULL;            /* not a directory */
        }
        return opendir(dirname);
}

#else /* not BSD */

/*
 * Dirent routines for old style file systems.
 */

#ifdef __STDC__
pointer malloc(unsigned);
void free(pointer);
int open(char *, int, ...);
int close(int);
int fstat(int, struct stat *);
#else
pointer malloc();
void free();
int open();
int close();
int fstat();
#endif


DIR *
opendir(dirname)
        char            *dirname;       /* name of directory */
        {
        register DIR    *dirp;          /* -> malloc'ed storage */
        register int    fd;             /* file descriptor for read */
        struct stat     statb;          /* result of fstat() */

#ifdef O_NDELAY
        fd = open(dirname, O_RDONLY|O_NDELAY);
#else
        fd = open(dirname, O_RDONLY);
#endif
        if (fd < 0)
                return NULL;            /* errno set by open() */

        if (fstat(fd, &statb) != 0 || !S_ISDIR(statb.st_mode)) {
                (void)close(fd);
                errno = ENOTDIR;
                return NULL;            /* not a directory */
        }

        if ((dirp = (DIR *)malloc(sizeof(DIR))) == NULL) {
                (void)close(fd);
                errno = ENOMEM;
                return NULL;            /* not enough memory */
        }

        dirp->dd_fd = fd;
        dirp->dd_nleft = 0;             /* refill needed */

        return dirp;
}



int
closedir(dirp)
        register DIR *dirp;             /* stream from opendir() */
        {
        register int fd;

        if (dirp == NULL) {
                errno = EFAULT;
                return -1;                      /* invalid pointer */
        }

        fd = dirp->dd_fd;
        free((pointer)dirp);
        return close(fd);
}



struct dirent *
readdir(dirp)
        register DIR *dirp;             /* stream from opendir() */
        {
        register struct direct *dp;
        register char *p, *q;
        register int i;

        do {
                if ((dirp->dd_nleft -= sizeof (struct direct)) < 0) {
                        if ((i = read(dirp->dd_fd,
                                           (char *)dirp->dd_buf,
                                           DIRBUFENT*sizeof(struct direct))) <= 0) {
                                if (i == 0)
                                        errno = 0;      /* unnecessary */
                                return NULL;            /* EOF or error */
                        }
                        dirp->dd_loc = dirp->dd_buf;
                        dirp->dd_nleft = i - sizeof (struct direct);
                }
                dp = dirp->dd_loc++;
        } while (dp->d_ino == 0);
        dirp->dd_entry.d_ino = dp->d_ino;

        /* now copy the name, nul terminating it */
        p = dp->d_name;
        q = dirp->dd_entry.d_name;
        i = DIRSIZ;
        while (--i >= 0 && *p != '\0')
                *q++ = *p++;
        *q = '\0';
        return &dirp->dd_entry;
}

#endif /* BSD */
#endif /* DIRENT */

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