/*      $OpenBSD: opendev.c,v 1.18 2025/08/25 14:59:13 claudio Exp $    */

/*
 * Copyright (c) 2000, Todd C. Miller.  All rights reserved.
 * Copyright (c) 1996, Jason Downs.  All rights reserved.
 *
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``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(S) 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.
 */

#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <paths.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>

#include <sys/ioctl.h>
#include <sys/limits.h>
#include <sys/disk.h>
#include <sys/dkio.h>

#include "util.h"

/*
 * This routine is a generic rewrite of the original code found in
 * disklabel(8).
 */
int
opendev(const char *path, int oflags, int dflags, char **realpath)
{
        static char namebuf[PATH_MAX];
        struct dk_diskmap dm;
        char *slash, *prefix;
        int fd, ret;

        /* Initial state */
        fd = -1;
        errno = ENOENT;

        if (dflags & OPENDEV_BLCK)
                prefix = "";                    /* block device */
        else
                prefix = "r";                   /* character device */

        if ((slash = strchr(path, '/'))) {
                strlcpy(namebuf, path, sizeof(namebuf));
                fd = open(namebuf, oflags);
        } else if (isduid(path, dflags)) {
                strlcpy(namebuf, path, sizeof(namebuf));
                if ((fd = open("/dev/diskmap", oflags)) != -1) {
                        bzero(&dm, sizeof(struct dk_diskmap));
                        dm.device = namebuf;
                        dm.fd = fd;
                        if (dflags & OPENDEV_PART)
                                dm.flags |= DM_OPENPART;
                        if (dflags & OPENDEV_BLCK)
                                dm.flags |= DM_OPENBLCK;

                        if (ioctl(fd, DIOCMAP, &dm) == -1) {
                                close(fd);
                                fd = -1;
                                errno = ENOENT;
                        }
                }
        }
        if (!slash && fd == -1 && errno == ENOENT) {
                if (dflags & OPENDEV_PART) {
                        /*
                         * First try raw partition (for removable drives)
                         */
                        ret = snprintf(namebuf, sizeof(namebuf), "%s%s%s%c",
                            _PATH_DEV, prefix, path, 'a' + getrawpartition());
                        if (ret < 0 || (size_t)ret >= sizeof(namebuf))
                                errno = ENAMETOOLONG;
                        else
                                fd = open(namebuf, oflags);
                }
                if (fd == -1 && errno == ENOENT) {
                        ret = snprintf(namebuf, sizeof(namebuf), "%s%s%s",
                            _PATH_DEV, prefix, path);
                        if (ret < 0 || (size_t)ret >= sizeof(namebuf))
                                errno = ENAMETOOLONG;
                        else
                                fd = open(namebuf, oflags);
                }
        }
        if (realpath)
                *realpath = namebuf;

        return (fd);
}