/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 1980, 1991, 1993, 1994
 *      The Regents of the University of California.  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.
 * 3. 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.
 */

#include <sys/param.h>
#include <sys/stat.h>
#include <sys/mount.h>
#include <sys/disklabel.h>

#include <ufs/ufs/extattr.h>
#include <ufs/ufs/quota.h>
#include <ufs/ufs/dinode.h>
#include <ufs/ufs/ufsmount.h>
#include <ufs/ffs/fs.h>

#include <protocols/dumprestore.h>

#include <ctype.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <fstab.h>
#include <libufs.h>
#include <limits.h>
#include <signal.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <timeconv.h>
#include <unistd.h>

#include "dump.h"
#include "pathnames.h"

int     mapsize;        /* size of the state maps */
char    *usedinomap;    /* map of allocated inodes */
char    *dumpdirmap;    /* map of directories to be dumped */
char    *dumpinomap;    /* map of files to be dumped */
char    *disk;          /* name of the disk file */
char    *tape;          /* name of the tape file */
char    *popenout;      /* popen(3) per-"tape" command */
int     level;          /* dump level of this dump */
int     uflag;          /* update flag */
int     diskfd;         /* disk file descriptor */
int     pipeout;        /* true => output to standard output */
int     density = 0;    /* density in bytes/0.1" " <- this is for hilit19 */
long    tapesize;       /* estimated tape size, blocks */
long    tsize;          /* tape size in 0.1" units */
int     etapes;         /* estimated number of tapes */
int     nonodump;       /* if set, do not honor UF_NODUMP user flags */
int     unlimited;      /* if set, write to end of medium */
int     cachesize = 0;  /* block cache size (in bytes), defaults to 0 */
int     rsync_friendly; /* be friendly with rsync */
int     notify = 0;     /* notify operator flag */
int     blockswritten = 0; /* number of blocks written on current tape */
int     tapeno = 0;     /* current tape number */
int     ntrec = NTREC;  /* # tape blocks in each tape record */
long    blocksperfile;  /* number of blocks per output file */
int     cartridge = 0;  /* Assume non-cartridge tape */
char    *host = NULL;   /* remote host (if any) */
time_t  tstart_writing; /* when started writing the first tape block */
time_t  tend_writing;   /* after writing the last tape block */
int     passno;         /* current dump pass number */
struct  fs *sblock;     /* the file system super block */
long    dev_bsize = 1;  /* recalculated below */
int     dev_bshift;     /* log2(dev_bsize) */
int     tp_bshift;      /* log2(TP_BSIZE) */
int     snapdump = 0;   /* dumping live filesystem, so use snapshot */

static char *getmntpt(char *, int *);
static long numarg(const char *, long, long);
static void obsolete(int *, char **[]);
static void usage(void) __dead2;

int
main(int argc, char *argv[])
{
        struct stat sb;
        ino_t ino;
        int dirty;
        union dinode *dp;
        struct fstab *dt;
        char *map, *mntpt;
        int ch, mode, mntflags;
        int i, ret, anydirskipped, bflag = 0, Tflag = 0, honorlevel = 1;
        int just_estimate = 0;
        ino_t maxino;
        char *tmsg;

        spcl.c_date = _time_to_time64(time(NULL));

        tsize = 0;      /* Default later, based on 'c' option for cart tapes */
        dumpdates = _PATH_DUMPDATES;
        popenout = NULL;
        tape = NULL;
        if (TP_BSIZE / DEV_BSIZE == 0 || TP_BSIZE % DEV_BSIZE != 0)
                quit("TP_BSIZE must be a multiple of DEV_BSIZE\n");
        level = 0;
        rsync_friendly = 0;

        if (argc < 2)
                usage();

        obsolete(&argc, &argv);
        while ((ch = getopt(argc, argv,
            "0123456789aB:b:C:cD:d:f:h:LnP:RrSs:T:uWw")) != -1)
                switch (ch) {
                /* dump level */
                case '0': case '1': case '2': case '3': case '4':
                case '5': case '6': case '7': case '8': case '9':
                        level = 10 * level + ch - '0';
                        break;

                case 'a':               /* `auto-size', Write to EOM. */
                        unlimited = 1;
                        break;

                case 'B':               /* blocks per output file */
                        blocksperfile = numarg("number of blocks per file",
                            1L, 0L);
                        break;

                case 'b':               /* blocks per tape write */
                        ntrec = numarg("number of blocks per write",
                            1L, 1000L);
                        break;

                case 'C':
                        cachesize = numarg("cachesize", 0, 0) * 1024 * 1024;
                        break;

                case 'c':               /* Tape is cart. not 9-track */
                        cartridge = 1;
                        break;

                case 'D':
                        dumpdates = optarg;
                        break;

                case 'd':               /* density, in bits per inch */
                        density = numarg("density", 10L, 327670L) / 10;
                        if (density >= 625 && !bflag)
                                ntrec = HIGHDENSITYTREC;
                        break;

                case 'f':               /* output file */
                        if (popenout != NULL)
                                errx(X_STARTUP, "You cannot use the P and f "
                                    "flags together.\n");
                        tape = optarg;
                        break;

                case 'h':
                        honorlevel = numarg("honor level", 0L, 10L);
                        break;

                case 'L':
                        snapdump = 1;
                        break;

                case 'n':               /* notify operators */
                        notify = 1;
                        break;

                case 'P':
                        if (tape != NULL)
                                errx(X_STARTUP, "You cannot use the P and f "
                                    "flags together.\n");
                        popenout = optarg;
                        break;

                case 'r': /* store slightly less data to be friendly to rsync */
                        if (rsync_friendly < 1)
                                rsync_friendly = 1;
                        break;

                case 'R': /* store even less data to be friendlier to rsync */
                        if (rsync_friendly < 2)
                                rsync_friendly = 2;
                        break;

                case 'S':               /* exit after estimating # of tapes */
                        just_estimate = 1;
                        break;

                case 's':               /* tape size, feet */
                        tsize = numarg("tape size", 1L, 0L) * 12 * 10;
                        break;

                case 'T':               /* time of last dump */
                        spcl.c_ddate = unctime(optarg);
                        if (spcl.c_ddate < 0) {
                                (void)fprintf(stderr, "bad time \"%s\"\n",
                                    optarg);
                                exit(X_STARTUP);
                        }
                        Tflag = 1;
                        lastlevel = -1;
                        break;

                case 'u':               /* update /etc/dumpdates */
                        uflag = 1;
                        break;

                case 'W':               /* what to do */
                case 'w':
                        lastdump(ch);
                        exit(X_FINOK);  /* do nothing else */

                default:
                        usage();
                }
        argc -= optind;
        argv += optind;

        if (argc < 1) {
                (void)fprintf(stderr, "Must specify disk or file system\n");
                exit(X_STARTUP);
        }
        disk = *argv++;
        argc--;
        if (argc >= 1) {
                (void)fprintf(stderr, "Unknown arguments to dump:");
                while (argc--)
                        (void)fprintf(stderr, " %s", *argv++);
                (void)fprintf(stderr, "\n");
                exit(X_STARTUP);
        }
        if (rsync_friendly && (level > 0)) {
                (void)fprintf(stderr, "%s %s\n", "rsync friendly options",
                    "can be used only with level 0 dumps.");
                exit(X_STARTUP);
        }
        if (Tflag && uflag) {
                (void)fprintf(stderr,
                    "You cannot use the T and u flags together.\n");
                exit(X_STARTUP);
        }
        if (popenout) {
                tape = "child pipeline process";
        } else if (tape == NULL && (tape = getenv("TAPE")) == NULL)
                tape = _PATH_DEFTAPE;
        if (strcmp(tape, "-") == 0) {
                pipeout++;
                tape = "standard output";
        }

        if (blocksperfile)
                blocksperfile = rounddown(blocksperfile, ntrec);
        else if (!unlimited) {
                /*
                 * Determine how to default tape size and density
                 *
                 *              density                         tape size
                 * 9-track      1600 bpi (160 bytes/.1")        2300 ft.
                 * 9-track      6250 bpi (625 bytes/.1")        2300 ft.
                 * cartridge    8000 bpi (100 bytes/.1")        1700 ft.
                 *                                              (450*4 - slop)
                 * hilit19 hits again: "
                 */
                if (density == 0)
                        density = cartridge ? 100 : 160;
                if (tsize == 0)
                        tsize = cartridge ? 1700L*120L : 2300L*120L;
        }

        if (strchr(tape, ':')) {
                host = tape;
                tape = strchr(host, ':');
                *tape++ = '\0';
#ifdef RDUMP
                if (strchr(tape, '\n')) {
                    (void)fprintf(stderr, "invalid characters in tape\n");
                    exit(X_STARTUP);
                }
                if (rmthost(host) == 0)
                        exit(X_STARTUP);
#else
                (void)fprintf(stderr, "remote dump not enabled\n");
                exit(X_STARTUP);
#endif
        }
        (void)setuid(getuid()); /* rmthost() is the only reason to be setuid */

        if (signal(SIGHUP, SIG_IGN) != SIG_IGN)
                signal(SIGHUP, sig);
        if (signal(SIGTRAP, SIG_IGN) != SIG_IGN)
                signal(SIGTRAP, sig);
        if (signal(SIGFPE, SIG_IGN) != SIG_IGN)
                signal(SIGFPE, sig);
        if (signal(SIGBUS, SIG_IGN) != SIG_IGN)
                signal(SIGBUS, sig);
        if (signal(SIGSEGV, SIG_IGN) != SIG_IGN)
                signal(SIGSEGV, sig);
        if (signal(SIGTERM, SIG_IGN) != SIG_IGN)
                signal(SIGTERM, sig);
        if (signal(SIGINT, interrupt) == SIG_IGN)
                signal(SIGINT, SIG_IGN);

        dump_getfstab();        /* /etc/fstab snarfed */
        /*
         *      disk can be either the full special file name,
         *      the suffix of the special file name,
         *      the special name missing the leading '/',
         *      the file system name with or without the leading '/'.
         */
        dt = fstabsearch(disk);
        if (dt != NULL) {
                disk = rawname(dt->fs_spec);
                if (disk == NULL)
                        errx(X_STARTUP, "%s: unknown file system", dt->fs_spec);
                (void)strncpy(spcl.c_dev, dt->fs_spec, NAMELEN);
                (void)strncpy(spcl.c_filesys, dt->fs_file, NAMELEN);
        } else {
                (void)strncpy(spcl.c_dev, disk, NAMELEN);
                (void)strncpy(spcl.c_filesys, "an unlisted file system",
                    NAMELEN);
        }
        spcl.c_dev[NAMELEN-1]='\0';
        spcl.c_filesys[NAMELEN-1]='\0';

        if ((mntpt = getmntpt(disk, &mntflags)) != NULL) {
                if (mntflags & MNT_RDONLY) {
                        if (snapdump != 0) {
                                msg("WARNING: %s\n",
                                    "-L ignored for read-only filesystem.");
                                snapdump = 0;
                        }
                } else if (snapdump == 0) {
                        msg("WARNING: %s\n",
                            "should use -L when dumping live read-write "
                            "filesystems!");
                } else {
                        char snapname[BUFSIZ], snapcmd[BUFSIZ];

                        snprintf(snapname, sizeof snapname, "%s/.snap", mntpt);
                        if ((stat(snapname, &sb) < 0) || !S_ISDIR(sb.st_mode)) {
                                msg("WARNING: %s %s\n",
                                    "-L requested but snapshot location",
                                    snapname);
                                msg("         %s: %s\n",
                                    "is not a directory",
                                    "dump downgraded, -L ignored");
                                snapdump = 0;
                        } else {
                                snprintf(snapname, sizeof snapname,
                                    "%s/.snap/dump_snapshot", mntpt);
                                snprintf(snapcmd, sizeof snapcmd, "%s %s %s",
                                    _PATH_MKSNAP_FFS, mntpt, snapname);
                                unlink(snapname);
                                if (system(snapcmd) != 0)
                                        errx(X_STARTUP, "Cannot create %s: %s\n",
                                            snapname, strerror(errno));
                                if ((diskfd = open(snapname, O_RDONLY)) < 0) {
                                        unlink(snapname);
                                        errx(X_STARTUP, "Cannot open %s: %s\n",
                                            snapname, strerror(errno));
                                }
                                unlink(snapname);
                                if (fstat(diskfd, &sb) != 0)
                                        err(X_STARTUP, "%s: stat", snapname);
                                spcl.c_date = _time_to_time64(sb.st_mtime);
                        }
                }
        } else if (snapdump != 0) {
                msg("WARNING: Cannot use -L on an unmounted filesystem.\n");
                snapdump = 0;
        }
        if (snapdump == 0) {
                if ((diskfd = open(disk, O_RDONLY)) < 0)
                        err(X_STARTUP, "Cannot open %s", disk);
                if (fstat(diskfd, &sb) != 0)
                        err(X_STARTUP, "%s: stat", disk);
                if (S_ISDIR(sb.st_mode))
                        errx(X_STARTUP, "%s: unknown file system", disk);
        }

        (void)strcpy(spcl.c_label, "none");
        (void)gethostname(spcl.c_host, NAMELEN);
        spcl.c_level = level;
        spcl.c_type = TS_TAPE;
        if (rsync_friendly) {
                /* don't store real dump times */
                spcl.c_date = 0;
                spcl.c_ddate = 0;
        }
        if (spcl.c_date == 0) {
                tmsg = "the epoch\n";
        } else {
                time_t t = _time64_to_time(spcl.c_date);
                tmsg = ctime(&t);
        }
        msg("Date of this level %d dump: %s", level, tmsg);

        if (!Tflag && (!rsync_friendly))
                getdumptime();          /* /etc/dumpdates snarfed */
        if (spcl.c_ddate == 0) {
                tmsg = "the epoch\n";
        } else {
                time_t t = _time64_to_time(spcl.c_ddate);
                tmsg = ctime(&t);
        }
        if (lastlevel < 0)
                msg("Date of last (level unknown) dump: %s", tmsg);
        else
                msg("Date of last level %d dump: %s", lastlevel, tmsg);

        msg("Dumping %s%s ", snapdump ? "snapshot of ": "", disk);
        if (dt != NULL)
                msgtail("(%s) ", dt->fs_file);
        if (host)
                msgtail("to %s on host %s\n", tape, host);
        else
                msgtail("to %s\n", tape);

        sync();
        if ((ret = sbget(diskfd, &sblock, UFS_STDSB, UFS_NOCSUM)) != 0) {
                switch (ret) {
                case ENOENT:
                        warn("Cannot find file system superblock");
                        return (1);
                default:
                        warn("Unable to read file system superblock");
                        return (1);
                }
        }
        dev_bsize = sblock->fs_fsize / fsbtodb(sblock, 1);
        dev_bshift = ffs(dev_bsize) - 1;
        if (dev_bsize != (1 << dev_bshift))
                quit("dev_bsize (%ld) is not a power of 2", dev_bsize);
        tp_bshift = ffs(TP_BSIZE) - 1;
        if (TP_BSIZE != (1 << tp_bshift))
                quit("TP_BSIZE (%d) is not a power of 2", TP_BSIZE);
        maxino = sblock->fs_ipg * sblock->fs_ncg;
        mapsize = roundup(howmany(maxino, CHAR_BIT), TP_BSIZE);
        usedinomap = (char *)calloc((unsigned) mapsize, sizeof(char));
        dumpdirmap = (char *)calloc((unsigned) mapsize, sizeof(char));
        dumpinomap = (char *)calloc((unsigned) mapsize, sizeof(char));
        tapesize = 3 * (howmany(mapsize * sizeof(char), TP_BSIZE) + 1);

        nonodump = spcl.c_level < honorlevel;

        passno = 1;
        setproctitle("%s: pass 1: regular files", disk);
        msg("mapping (Pass I) [regular files]\n");
        anydirskipped = mapfiles(maxino, &tapesize);

        passno = 2;
        setproctitle("%s: pass 2: directories", disk);
        msg("mapping (Pass II) [directories]\n");
        while (anydirskipped) {
                anydirskipped = mapdirs(maxino, &tapesize);
        }

        if (pipeout || unlimited) {
                tapesize += 10; /* 10 trailer blocks */
                msg("estimated %ld tape blocks.\n", tapesize);
        } else {
                double fetapes;

                if (blocksperfile)
                        fetapes = (double) tapesize / blocksperfile;
                else if (cartridge) {
                        /* Estimate number of tapes, assuming streaming stops at
                           the end of each block written, and not in mid-block.
                           Assume no erroneous blocks; this can be compensated
                           for with an artificially low tape size. */
                        fetapes =
                        (         (double) tapesize     /* blocks */
                                * TP_BSIZE      /* bytes/block */
                                * (1.0/density) /* 0.1" / byte " */
                          +
                                  (double) tapesize     /* blocks */
                                * (1.0/ntrec)   /* streaming-stops per block */
                                * 15.48         /* 0.1" / streaming-stop " */
                        ) * (1.0 / tsize );     /* tape / 0.1" " */
                } else {
                        /* Estimate number of tapes, for old fashioned 9-track
                           tape */
                        int tenthsperirg = (density == 625) ? 3 : 7;
                        fetapes =
                        (         (double) tapesize     /* blocks */
                                * TP_BSIZE      /* bytes / block */
                                * (1.0/density) /* 0.1" / byte " */
                          +
                                  (double) tapesize     /* blocks */
                                * (1.0/ntrec)   /* IRG's / block */
                                * tenthsperirg  /* 0.1" / IRG " */
                        ) * (1.0 / tsize );     /* tape / 0.1" " */
                }
                etapes = fetapes;               /* truncating assignment */
                etapes++;
                /* count the dumped inodes map on each additional tape */
                tapesize += (etapes - 1) *
                        (howmany(mapsize * sizeof(char), TP_BSIZE) + 1);
                tapesize += etapes + 10;        /* headers + 10 trailer blks */
                msg("estimated %ld tape blocks on %3.2f tape(s).\n",
                    tapesize, fetapes);
        }

        /*
         * If the user only wants an estimate of the number of
         * tapes, exit now.
         */
        if (just_estimate)
                exit(0);

        /*
         * Allocate tape buffer.
         */
        if (!alloctape())
                quit(
        "can't allocate tape buffers - try a smaller blocking factor.\n");

        startnewtape(1);
        (void)time((time_t *)&(tstart_writing));
        dumpmap(usedinomap, TS_CLRI, maxino - 1);

        passno = 3;
        setproctitle("%s: pass 3: directories", disk);
        msg("dumping (Pass III) [directories]\n");
        dirty = 0;              /* XXX just to get gcc to shut up */
        for (map = dumpdirmap, ino = 1; ino < maxino; ino++) {
                if (((ino - 1) % CHAR_BIT) == 0)        /* map is offset by 1 */
                        dirty = *map++;
                else
                        dirty >>= 1;
                if ((dirty & 1) == 0)
                        continue;
                /*
                 * Skip directory inodes deleted and maybe reallocated
                 */
                dp = getino(ino, &mode);
                if (mode != IFDIR)
                        continue;
                (void)dumpino(dp, ino);
        }

        passno = 4;
        setproctitle("%s: pass 4: regular files", disk);
        msg("dumping (Pass IV) [regular files]\n");
        for (map = dumpinomap, ino = 1; ino < maxino; ino++) {
                if (((ino - 1) % CHAR_BIT) == 0)        /* map is offset by 1 */
                        dirty = *map++;
                else
                        dirty >>= 1;
                if ((dirty & 1) == 0)
                        continue;
                /*
                 * Skip inodes deleted and reallocated as directories.
                 */
                dp = getino(ino, &mode);
                if (mode == IFDIR)
                        continue;
                (void)dumpino(dp, ino);
        }

        (void)time((time_t *)&(tend_writing));
        spcl.c_type = TS_END;
        for (i = 0; i < ntrec; i++)
                writeheader(maxino - 1);
        if (pipeout)
                msg("DUMP: %jd tape blocks\n", (intmax_t)spcl.c_tapea);
        else
                msg("DUMP: %jd tape blocks on %d volume%s\n",
                    (intmax_t)spcl.c_tapea, spcl.c_volume,
                    (spcl.c_volume == 1) ? "" : "s");

        /* report dump performance, avoid division through zero */
        if (tend_writing - tstart_writing == 0)
                msg("finished in less than a second\n");
        else
                msg("finished in %jd seconds, throughput %jd KBytes/sec\n",
                    (intmax_t)tend_writing - tstart_writing, 
                    (intmax_t)(spcl.c_tapea / 
                    (tend_writing - tstart_writing)));

        putdumptime();
        trewind();
        broadcast("DUMP IS DONE!\a\a\n");
        msg("DUMP IS DONE\n");
        Exit(X_FINOK);
        /* NOTREACHED */
}

static void
usage(void)
{
        fprintf(stderr,
                "usage: dump [-0123456789acLnSu] [-B records] [-b blocksize] [-C cachesize]\n"
                "            [-D dumpdates] [-d density] [-f file | -P pipecommand] [-h level]\n"
                "            [-s feet] [-T date] filesystem\n"
                "       dump -W | -w\n");
        exit(X_STARTUP);
}

/*
 * Check to see if a disk is currently mounted.
 */
static char *
getmntpt(char *name, int *mntflagsp)
{
        long mntsize, i;
        struct statfs *mntbuf;

        mntsize = getmntinfo(&mntbuf, MNT_NOWAIT);
        for (i = 0; i < mntsize; i++) {
                if (!strcmp(mntbuf[i].f_mntfromname, name)) {
                        *mntflagsp = mntbuf[i].f_flags;
                        return (mntbuf[i].f_mntonname);
                }
        }
        return (0);
}

/*
 * Pick up a numeric argument.  It must be nonnegative and in the given
 * range (except that a vmax of 0 means unlimited).
 */
static long
numarg(const char *meaning, long vmin, long vmax)
{
        char *p;
        long val;

        val = strtol(optarg, &p, 10);
        if (*p)
                errx(1, "illegal %s -- %s", meaning, optarg);
        if (val < vmin || (vmax && val > vmax))
                errx(1, "%s must be between %ld and %ld", meaning, vmin, vmax);
        return (val);
}

void
sig(int signo)
{
        switch(signo) {
        case SIGALRM:
        case SIGBUS:
        case SIGFPE:
        case SIGHUP:
        case SIGTERM:
        case SIGTRAP:
                if (pipeout)
                        quit("Signal on pipe: cannot recover\n");
                msg("Rewriting attempted as response to unknown signal.\n");
                (void)fflush(stderr);
                (void)fflush(stdout);
                close_rewind();
                exit(X_REWRITE);
                /* NOTREACHED */
        case SIGSEGV:
                msg("SIGSEGV: ABORTING!\n");
                (void)signal(SIGSEGV, SIG_DFL);
                (void)kill(0, SIGSEGV);
                /* NOTREACHED */
        }
}

char *
rawname(char *cp)
{
        struct stat sb;

        /*
         * Ensure that the device passed in is a raw device.
         */
        if (stat(cp, &sb) == 0 && (sb.st_mode & S_IFMT) == S_IFCHR)
                return (cp);

        /*
         * Since there's only one device type now, we can't construct any
         * better name, so we have to return NULL.
         */
        return (NULL);
}

/*
 * obsolete --
 *      Change set of key letters and ordered arguments into something
 *      getopt(3) will like.
 */
static void
obsolete(int *argcp, char **argvp[])
{
        int argc, flags;
        char *ap, **argv, *flagsp, **nargv, *p;

        /* Setup. */
        argv = *argvp;
        argc = *argcp;

        /*
         * Return if no arguments or first argument has leading
         * dash or slash.
         */
        ap = argv[1];
        if (argc == 1 || *ap == '-' || *ap == '/')
                return;

        /* Allocate space for new arguments. */
        if ((*argvp = nargv = malloc((argc + 1) * sizeof(char *))) == NULL ||
            (p = flagsp = malloc(strlen(ap) + 2)) == NULL)
                err(1, NULL);

        *nargv++ = *argv;
        argv += 2;

        for (flags = 0; *ap; ++ap) {
                switch (*ap) {
                case 'B':
                case 'b':
                case 'd':
                case 'f':
                case 'D':
                case 'C':
                case 'h':
                case 's':
                case 'T':
                        if (*argv == NULL) {
                                warnx("option requires an argument -- %c", *ap);
                                usage();
                        }
                        if ((nargv[0] = malloc(strlen(*argv) + 2 + 1)) == NULL)
                                err(1, NULL);
                        nargv[0][0] = '-';
                        nargv[0][1] = *ap;
                        (void)strcpy(&nargv[0][2], *argv);
                        ++argv;
                        ++nargv;
                        break;
                default:
                        if (!flags) {
                                *p++ = '-';
                                flags = 1;
                        }
                        *p++ = *ap;
                        break;
                }
        }

        /* Terminate flags. */
        if (flags) {
                *p = '\0';
                *nargv++ = flagsp;
        } else
                free(flagsp);

        /* Copy remaining arguments. */
        while ((*nargv++ = *argv++));

        /* Update argument count. */
        *argcp = nargv - *argvp - 1;
}