sys/common/getdents.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 1994 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#pragma ident   "%Z%%M% %I% %E% SMI"

#include <unistd.h>
#include <sys/types.h>
#include <sys/dirent.h>
#include <sys/syscall.h>
#include <sys/param.h>
#include <sys/errno.h>

#define ALIGN   4

extern int errno;

struct n_dirent{
    unsigned long   d_ino;
    long        d_off;
    unsigned short  d_reclen;
    char        d_name[1];
};


int getdents(fd, buf, bytes)
int fd;
char *buf;
int bytes;
{
    return(bc_getdents(fd, buf, bytes));
}


int bc_getdents(fd, buf, bytes)
int fd;
char *buf;
int bytes;
{
    int ret, nbytes;
    char *nbuf;
    struct dirent *dir;
    struct n_dirent *ndir;
    int count=0;
    off_t last_off;

    if (buf == (char *)0 || buf == (char *)-1) {
        errno = EFAULT;
        return(-1);
    }

    nbytes = bytes; /* buffer can only be as large as user expects */

    if ((nbuf = (char *)malloc(nbytes)) == NULL) {
        return(-1);
    }

    if ((ret = _syscall(SYS_getdents, fd, nbuf, nbytes)) == -1) {
        free(nbuf);
        return(ret);
    }


    dir = (struct dirent *)buf;
    ndir = (struct n_dirent *)nbuf; /* source directory format */

    while ((((int)(((char *)dir) + sizeof(struct n_dirent) +
        strlen(ndir->d_name) + ALIGN) & ~(ALIGN - 1)) <
        (int)(buf + bytes)) &&
        ((char *)ndir + sizeof(struct n_dirent) <= (nbuf + ret))) {
        dir->d_off = ndir->d_off;
        dir->d_fileno = ndir->d_ino;    /* NOT VALID */
        dir->d_namlen = strlen(ndir->d_name);
        dir->d_reclen = (short)((sizeof(struct dirent) - MAXNAMLEN +
            dir->d_namlen + ALIGN) & -ALIGN);
        strncpy(dir->d_name, ndir->d_name, dir->d_namlen);
        dir->d_name[dir->d_namlen] = '\0';
        count += dir->d_reclen;
        last_off = ndir->d_off;
        dir  = (struct dirent *)((char *)dir +
                    ((int)( dir->d_reclen)));
        ndir = (struct n_dirent *)((char *)ndir +
                    ((int)(ndir->d_reclen)));
    }

    /*
     * Seek to the next entry in the directory. If all entries
     * in ndir were not copied to dir, the next getdents syscall
     * will start reading from there.
     */
    (void)lseek(fd, last_off, SEEK_SET);
    free(nbuf);
    return(count);
}