/*      $OpenBSD: readlabel.c,v 1.16 2025/09/17 16:16:20 deraadt Exp $  */

/*
 * 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 <sys/types.h>
#include <sys/disk.h>
#include <sys/dkio.h>
#define DKTYPENAMES
#include <sys/disklabel.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <stdio.h>
#include <err.h>
#include <errno.h>
#include <limits.h>
#include <fcntl.h>
#include <paths.h>
#include <string.h>
#include <unistd.h>

#include "util.h"

/*
 * Try to get a disklabel for the specified device, and return mount_xxx
 * style filesystem type name for the specified partition.
 */
char *
readlabelfs(char *device, int verbose)
{
        char rpath[PATH_MAX];
        struct dk_diskmap dm;
        struct disklabel dk;
        char part, *type;
        struct stat sbuf;
        int fd = -1, partno;

        /* Perform disk mapping if device is given as a DUID. */
        if (isduid(device, 0)) {
                if ((fd = open("/dev/diskmap", O_RDONLY|O_CLOEXEC)) != -1) {
                        bzero(&dm, sizeof(struct dk_diskmap));
                        strlcpy(rpath, device, sizeof(rpath));
                        part = rpath[strlen(rpath) - 1];
                        dm.device = rpath;
                        dm.fd = fd;
                        dm.flags = DM_OPENPART;
                        if (ioctl(fd, DIOCMAP, &dm) == -1)
                                close(fd);
                        else
                                goto disklabel;
                }
        }

        /* Assuming device is of the form /dev/??p, build a raw partition. */
        if (stat(device, &sbuf) == -1) {
                if (verbose)
                        warn("%s", device);
                return (NULL);
        }
        switch (sbuf.st_mode & S_IFMT) {
        case S_IFCHR:
                /* Ok... already a raw device.  Hmm. */
                strlcpy(rpath, device, sizeof(rpath));

                /* Change partition name. */
                part = rpath[strlen(rpath) - 1];
                rpath[strlen(rpath) - 1] = 'a' + getrawpartition();
                break;
        case S_IFBLK:
                if (strlen(device) > sizeof(_PATH_DEV) - 1) {
                        snprintf(rpath, sizeof(rpath), "%sr%s", _PATH_DEV,
                            &device[sizeof(_PATH_DEV) - 1]);
                        /* Change partition name. */
                        part = rpath[strlen(rpath) - 1];
                        rpath[strlen(rpath) - 1] = 'a' + getrawpartition();
                        break;
                }
                /* FALLTHROUGH */
        default:
                if (verbose)
                        warnx("%s: not a device node", device);
                return (NULL);
        }

        /* If rpath doesn't exist, change that partition back. */
        fd = open(rpath, O_RDONLY|O_CLOEXEC);
        if (fd == -1) {
                if (errno == ENOENT) {
                        rpath[strlen(rpath) - 1] = part;

                        fd = open(rpath, O_RDONLY|O_CLOEXEC);
                        if (fd == -1) {
                                if (verbose)
                                        warn("%s", rpath);
                                return (NULL);
                        }
                } else {
                        if (verbose)
                                warn("%s", rpath);
                        return (NULL);
                }
        }

disklabel:
        partno = DL_PARTNAME2NUM(part);
        if (partno == -1) {
                if (verbose)
                        warn("%s: diskmap provided weird partition", rpath);
                close(fd);
                return NULL;
        }
        if (ioctl(fd, DIOCGDINFO, &dk) == -1) {
                if (verbose)
                        warn("%s: couldn't read disklabel", rpath);
                close(fd);
                return (NULL);
        }
        close(fd);

        if (dk.d_partitions[partno].p_fstype >= FSMAXTYPES) {
                if (verbose)
                        warnx("%s: bad filesystem type in label", rpath);
                return (NULL);
        }

        type = fstypesnames[dk.d_partitions[partno].p_fstype];
        return ((type[0] == '\0') ? NULL : type);
}