/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 1980, 1989, 1993
 *      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/mount.h>
#include <sys/socket.h>
#include <sys/stat.h>

#include <netdb.h>
#include <rpc/rpc.h>
#include <rpcsvc/mount.h>
#include <nfs/nfssvc.h>

#include <ctype.h>
#include <err.h>
#include <errno.h>
#include <fstab.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "mounttab.h"

/* used by md_detach() */
#include <sys/ioctl.h>
#include <sys/mdioctl.h>
#include <fcntl.h>
#include <paths.h>

#define DEV_MD     _PATH_DEV   MD_NAME
#define DEV_MDCTL   _PATH_DEV  MDCTL_NAME

typedef enum { FIND, REMOVE, CHECKUNIQUE } dowhat;

static struct addrinfo *nfshost_ai = NULL;
static int      dflag, fflag, vflag;
static int      all;
static char     *nfshost;

struct statfs *checkmntlist(char *);
int      checkvfsname (const char *, char **);
struct statfs *getmntentry(const char *fromname, const char *onname,
             fsid_t *fsid, dowhat what);
char   **makevfslist (const char *);
size_t   mntinfo (struct statfs **);
int      namematch (struct addrinfo *);
int      parsehexfsid(const char *hex, fsid_t *fsid);
int      sacmp (void *, void *);
int      umountall (char **);
int      checkname (char *, char **);
int      umountfs(struct statfs *sfs);
void     usage (void);
int      xdr_dir (XDR *, char *);
int      md_detach(const char *);

int
main(int argc, char *argv[])
{
        int errs, ch, mntsize, error, nfsforce, ret;
        char **typelist = NULL;
        struct statfs *mntbuf, *sfs;
        struct addrinfo hints;

        nfsforce = all = errs = 0;
        while ((ch = getopt(argc, argv, "AadF:fh:Nnt:v")) != -1)
                switch (ch) {
                case 'A':
                        all = 2;
                        break;
                case 'a':
                        all = 1;
                        break;
                case 'd':
                        dflag = 1;
                        break;
                case 'F':
                        setfstab(optarg);
                        break;
                case 'f':
                        fflag |= MNT_FORCE;
                        break;
                case 'h':       /* -h implies -A. */
                        all = 2;
                        nfshost = optarg;
                        break;
                case 'N':
                        nfsforce = 1;
                        break;
                case 'n':
                        fflag |= MNT_NONBUSY;
                        break;
                case 't':
                        if (typelist != NULL)
                                err(1, "only one -t option may be specified");
                        typelist = makevfslist(optarg);
                        break;
                case 'v':
                        vflag = 1;
                        break;
                default:
                        usage();
                        /* NOTREACHED */
                }
        argc -= optind;
        argv += optind;

        if ((fflag & MNT_FORCE) != 0 && (fflag & MNT_NONBUSY) != 0)
                err(1, "-f and -n are mutually exclusive");

        if ((argc == 0 && !all) || (argc != 0 && all))
                usage();

        if (nfsforce != 0 && (argc == 0 || nfshost != NULL || typelist != NULL))
                usage();

        /* -h implies "-t nfs" if no -t flag. */
        if ((nfshost != NULL) && (typelist == NULL))
                typelist = makevfslist("nfs");

        if (nfshost != NULL) {
                memset(&hints, 0, sizeof hints);
                error = getaddrinfo(nfshost, NULL, &hints, &nfshost_ai);
                if (error)
                        errx(1, "%s: %s", nfshost, gai_strerror(error));
        }

        switch (all) {
        case 2:
                if ((mntsize = mntinfo(&mntbuf)) <= 0)
                        break;
                /*
                 * We unmount the nfs-mounts in the reverse order
                 * that they were mounted.
                 */
                for (errs = 0, mntsize--; mntsize > 0; mntsize--) {
                        sfs = &mntbuf[mntsize];
                        if (checkvfsname(sfs->f_fstypename, typelist))
                                continue;
                        if (strcmp(sfs->f_mntonname, "/dev") == 0)
                                continue;
                        if (umountfs(sfs) != 0)
                                errs = 1;
                }
                free(mntbuf);
                break;
        case 1:
                if (setfsent() == 0)
                        err(1, "%s", getfstab());
                errs = umountall(typelist);
                break;
        case 0:
                for (errs = 0; *argv != NULL; ++argv)
                        if (nfsforce != 0) {
                                /*
                                 * First do the nfssvc() syscall to shut down
                                 * the mount point and then do the forced
                                 * dismount.
                                 */
                                ret = nfssvc(NFSSVC_FORCEDISM, *argv);
                                if (ret >= 0)
                                        ret = unmount(*argv, MNT_FORCE);
                                if (ret < 0) {
                                        warn("%s", *argv);
                                        errs = 1;
                                }
                        } else if (checkname(*argv, typelist) != 0)
                                errs = 1;
                break;
        }
        exit(errs);
}

int
umountall(char **typelist)
{
        struct xvfsconf vfc;
        struct fstab *fs;
        int rval;
        char *cp;
        static int firstcall = 1;

        if ((fs = getfsent()) != NULL)
                firstcall = 0;
        else if (firstcall)
                errx(1, "fstab reading failure");
        else
                return (0);
        do {
                /* Ignore the root. */
                if (strcmp(fs->fs_file, "/") == 0)
                        continue;
                /*
                 * !!!
                 * Historic practice: ignore unknown FSTAB_* fields.
                 */
                if (strcmp(fs->fs_type, FSTAB_RW) &&
                    strcmp(fs->fs_type, FSTAB_RO) &&
                    strcmp(fs->fs_type, FSTAB_RQ))
                        continue;
                /* Ignore unknown file system types. */
                if (getvfsbyname(fs->fs_vfstype, &vfc) == -1)
                        continue;
                if (checkvfsname(fs->fs_vfstype, typelist))
                        continue;

                /*
                 * We want to unmount the file systems in the reverse order
                 * that they were mounted.  So, we save off the file name
                 * in some allocated memory, and then call recursively.
                 */
                if ((cp = malloc((size_t)strlen(fs->fs_file) + 1)) == NULL)
                        err(1, "malloc failed");
                (void)strcpy(cp, fs->fs_file);
                rval = umountall(typelist);
                rval = checkname(cp, typelist) || rval;
                free(cp);
                return (rval);
        } while ((fs = getfsent()) != NULL);
        return (0);
}

/*
 * Do magic checks on mountpoint/device/fsid, and then call unmount(2).
 */
int
checkname(char *mntname, char **typelist)
{
        char buf[MAXPATHLEN];
        struct statfs sfsbuf;
        struct stat sb;
        struct statfs *sfs;
        char *delimp;
        dev_t dev;
        int len;

        /*
         * 1. Check if the name exists in the mounttable.
         */
        sfs = checkmntlist(mntname);
        /*
         * 2. Remove trailing slashes if there are any. After that
         * we look up the name in the mounttable again.
         */
        if (sfs == NULL) {
                len = strlen(mntname);
                while (len > 1 && mntname[len - 1] == '/')
                        mntname[--len] = '\0';
                sfs = checkmntlist(mntname);
        }
        /*
         * 3. Check if the deprecated NFS syntax with an '@' has been used
         * and translate it to the ':' syntax. Look up the name in the
         * mount table again.
         */
        if (sfs == NULL && (delimp = strrchr(mntname, '@')) != NULL) {
                snprintf(buf, sizeof(buf), "%s:%.*s", delimp + 1,
                    (int)(delimp - mntname), mntname);
                len = strlen(buf);
                while (len > 1 && buf[len - 1] == '/')
                        buf[--len] = '\0';
                sfs = checkmntlist(buf);
        }
        /*
         * 4. Resort to a statfs(2) call. This is the last check so that
         * hung NFS filesystems for example can be unmounted without
         * potentially blocking forever in statfs() as long as the
         * filesystem is specified unambiguously. This covers all the
         * hard cases such as symlinks and mismatches between the
         * mount list and reality.
         * We also do this if an ambiguous mount point was specified.
         */
        if (sfs == NULL || (getmntentry(NULL, mntname, NULL, FIND) != NULL &&
            getmntentry(NULL, mntname, NULL, CHECKUNIQUE) == NULL)) {
                if (statfs(mntname, &sfsbuf) != 0) {
                        warn("%s: statfs", mntname);
                } else if (stat(mntname, &sb) != 0) {
                        warn("%s: stat", mntname);
                } else if (S_ISDIR(sb.st_mode)) {
                        /* Check that `mntname' is the root directory. */
                        dev = sb.st_dev;
                        snprintf(buf, sizeof(buf), "%s/..", mntname);
                        if (stat(buf, &sb) != 0) {
                                warn("%s: stat", buf);
                        } else if (sb.st_dev == dev) {
                                warnx("%s: not a file system root directory",
                                    mntname);
                                return (1);
                        } else
                                sfs = &sfsbuf;
                }
        }
        if (sfs == NULL) {
                warnx("%s: unknown file system", mntname);
                return (1);
        }
        if (checkvfsname(sfs->f_fstypename, typelist))
                return (1);
        return (umountfs(sfs));
}

/*
 * NFS stuff and unmount(2) call
 */
int
umountfs(struct statfs *sfs)
{
        char fsidbuf[64];
        enum clnt_stat clnt_stat;
        struct timeval try;
        struct addrinfo *ai, hints;
        int do_rpc;
        CLIENT *clp;
        char *nfsdirname, *orignfsdirname;
        char *hostp, *delimp;
        char buf[1024];
        struct nfscl_dumpmntopts dumpmntopts;
        const char *proto_ptr = NULL;

        ai = NULL;
        do_rpc = 0;
        hostp = NULL;
        nfsdirname = delimp = orignfsdirname = NULL;
        memset(&hints, 0, sizeof hints);

        if (strcmp(sfs->f_fstypename, "nfs") == 0) {
                if ((nfsdirname = strdup(sfs->f_mntfromname)) == NULL)
                        err(1, "strdup");
                orignfsdirname = nfsdirname;
                if (*nfsdirname == '[' &&
                    (delimp = strchr(nfsdirname + 1, ']')) != NULL &&
                    *(delimp + 1) == ':') {
                        hostp = nfsdirname + 1;
                        nfsdirname = delimp + 2;
                } else if ((delimp = strrchr(nfsdirname, ':')) != NULL) {
                        hostp = nfsdirname;
                        nfsdirname = delimp + 1;
                }
                if (hostp != NULL) {
                        *delimp = '\0';
                        getaddrinfo(hostp, NULL, &hints, &ai);
                        if (ai == NULL) {
                                warnx("can't get net id for host");
                        }
                }

                /*
                 * Check if we have to start the rpc-call later.
                 * If there are still identical nfs-names mounted,
                 * we skip the rpc-call. Obviously this has to
                 * happen before unmount(2), but it should happen
                 * after the previous namecheck.
                 * A non-NULL return means that this is the last
                 * mount from mntfromname that is still mounted.
                 */
                if (getmntentry(sfs->f_mntfromname, NULL, NULL,
                    CHECKUNIQUE) != NULL) {
                        do_rpc = 1;
                        proto_ptr = "udp";
                        /*
                         * Try and find out whether this NFS mount is NFSv4 and
                         * what protocol is being used. If this fails, the
                         * default is NFSv2,3 and use UDP for the Unmount RPC.
                         */
                        dumpmntopts.ndmnt_fname = sfs->f_mntonname;
                        dumpmntopts.ndmnt_buf = buf;
                        dumpmntopts.ndmnt_blen = sizeof(buf);
                        if (nfssvc(NFSSVC_DUMPMNTOPTS, &dumpmntopts) >= 0) {
                                if (strstr(buf, "nfsv4,") != NULL)
                                        do_rpc = 0;
                                else if (strstr(buf, ",tcp,") != NULL)
                                        proto_ptr = "tcp";
                        }
                }
        }

        if (!namematch(ai)) {
                free(orignfsdirname);
                return (1);
        }
        /* First try to unmount using the file system ID. */
        snprintf(fsidbuf, sizeof(fsidbuf), "FSID:%d:%d", sfs->f_fsid.val[0],
            sfs->f_fsid.val[1]);
        if (unmount(fsidbuf, fflag | MNT_BYFSID) != 0) {
                /* XXX, non-root users get a zero fsid, so don't warn. */
                if (errno != ENOENT || sfs->f_fsid.val[0] != 0 ||
                    sfs->f_fsid.val[1] != 0)
                        warn("unmount of %s failed", sfs->f_mntonname);
                if (errno != ENOENT) {
                        free(orignfsdirname);
                        return (1);
                }
                /* Compatibility for old kernels. */
                if (sfs->f_fsid.val[0] != 0 || sfs->f_fsid.val[1] != 0)
                        warnx("retrying using path instead of file system ID");
                if (unmount(sfs->f_mntonname, fflag) != 0) {
                        warn("unmount of %s failed", sfs->f_mntonname);
                        free(orignfsdirname);
                        return (1);
                }
        }
        /* Mark this file system as unmounted. */
        getmntentry(NULL, NULL, &sfs->f_fsid, REMOVE);
        if (vflag)
                (void)printf("%s: unmount from %s\n", sfs->f_mntfromname,
                    sfs->f_mntonname);
        /*
         * Report to mountd-server which nfsname
         * has been unmounted.
         */
        if (ai != NULL && !(fflag & MNT_FORCE) && do_rpc) {
                clp = clnt_create(hostp, MOUNTPROG, MOUNTVERS3, proto_ptr);
                if (clp  == NULL) {
                        warnx("%s: %s", hostp,
                            clnt_spcreateerror("MOUNTPROG"));
                        free(orignfsdirname);
                        return (1);
                }
                clp->cl_auth = authsys_create_default();
                try.tv_sec = 20;
                try.tv_usec = 0;
                clnt_stat = clnt_call(clp, MOUNTPROC_UMNT, (xdrproc_t)xdr_dir,
                    nfsdirname, (xdrproc_t)xdr_void, (caddr_t)0, try);
                if (clnt_stat != RPC_SUCCESS) {
                        warnx("%s: %s", hostp,
                            clnt_sperror(clp, "RPCMNT_UMOUNT"));
                        free(orignfsdirname);
                        return (1);
                }
                /*
                 * Remove the unmounted entry from /var/db/mounttab.
                 */
                if (read_mtab()) {
                        clean_mtab(hostp, nfsdirname, vflag);
                        if(!write_mtab(vflag))
                                warnx("cannot remove mounttab entry %s:%s",
                                    hostp, nfsdirname);
                        free_mtab();
                }
                auth_destroy(clp->cl_auth);
                clnt_destroy(clp);
        }
        free(orignfsdirname);

        if (dflag) {
                if (md_detach(sfs->f_mntfromname) == 0) {
                        if (vflag)
                                (void)printf("%s: detached\n",
                                    sfs->f_mntfromname);
                } else if (!all)
                        return (-1);
        }

        return (0);
}

struct statfs *
getmntentry(const char *fromname, const char *onname, fsid_t *fsid, dowhat what)
{
        static struct statfs *mntbuf;
        static size_t mntsize = 0;
        static int *mntcheck = NULL;
        struct statfs *sfs, *foundsfs;
        int i, count;

        if (mntsize <= 0) {
                if ((mntsize = mntinfo(&mntbuf)) <= 0)
                        return (NULL);
        }
        if (mntcheck == NULL) {
                if ((mntcheck = calloc(mntsize + 1, sizeof(int))) == NULL)
                        err(1, "calloc");
        }
        /*
         * We want to get the file systems in the reverse order
         * that they were mounted. Unmounted file systems are marked
         * in a table called 'mntcheck'.
         */
        count = 0;
        foundsfs = NULL;
        for (i = mntsize - 1; i >= 0; i--) {
                if (mntcheck[i])
                        continue;
                sfs = &mntbuf[i];
                if (fromname != NULL && strcmp(sfs->f_mntfromname,
                    fromname) != 0)
                        continue;
                if (onname != NULL && strcmp(sfs->f_mntonname, onname) != 0)
                        continue;
                if (fsid != NULL && fsidcmp(&sfs->f_fsid, fsid) != 0)
                        continue;

                switch (what) {
                case CHECKUNIQUE:
                        foundsfs = sfs;
                        count++;
                        continue;
                case REMOVE:
                        mntcheck[i] = 1;
                        break;
                default:
                        break;
                }
                return (sfs);
        }

        if (what == CHECKUNIQUE && count == 1)
                return (foundsfs);
        return (NULL);
}

int
sacmp(void *sa1, void *sa2)
{
        void *p1, *p2;
        int len;

        if (((struct sockaddr *)sa1)->sa_family !=
            ((struct sockaddr *)sa2)->sa_family)
                return (1);

        switch (((struct sockaddr *)sa1)->sa_family) {
        case AF_INET:
                p1 = &((struct sockaddr_in *)sa1)->sin_addr;
                p2 = &((struct sockaddr_in *)sa2)->sin_addr;
                len = 4;
                break;
        case AF_INET6:
                p1 = &((struct sockaddr_in6 *)sa1)->sin6_addr;
                p2 = &((struct sockaddr_in6 *)sa2)->sin6_addr;
                len = 16;
                if (((struct sockaddr_in6 *)sa1)->sin6_scope_id !=
                    ((struct sockaddr_in6 *)sa2)->sin6_scope_id)
                        return (1);
                break;
        default:
                return (1);
        }

        return memcmp(p1, p2, len);
}

int
namematch(struct addrinfo *ai)
{
        struct addrinfo *aip;

        if (nfshost == NULL || nfshost_ai == NULL)
                return (1);

        while (ai != NULL) {
                aip = nfshost_ai;
                while (aip != NULL) {
                        if (sacmp(ai->ai_addr, aip->ai_addr) == 0)
                                return (1);
                        aip = aip->ai_next;
                }
                ai = ai->ai_next;
        }

        return (0);
}

struct statfs *
checkmntlist(char *mntname)
{
        struct statfs *sfs;
        fsid_t fsid;

        sfs = NULL;
        if (parsehexfsid(mntname, &fsid) == 0)
                sfs = getmntentry(NULL, NULL, &fsid, FIND);
        if (sfs == NULL)
                sfs = getmntentry(NULL, mntname, NULL, FIND);
        if (sfs == NULL)
                sfs = getmntentry(mntname, NULL, NULL, FIND);
        return (sfs);
}

size_t
mntinfo(struct statfs **mntbuf)
{
        static struct statfs *origbuf;
        size_t bufsize;
        int mntsize;

        mntsize = getfsstat(NULL, 0, MNT_NOWAIT);
        if (mntsize <= 0)
                return (0);
        bufsize = (mntsize + 1) * sizeof(struct statfs);
        if ((origbuf = malloc(bufsize)) == NULL)
                err(1, "malloc");
        mntsize = getfsstat(origbuf, (long)bufsize, MNT_NOWAIT);
        *mntbuf = origbuf;
        return (mntsize);
}

/*
 * Convert a hexadecimal filesystem ID to an fsid_t.
 * Returns 0 on success.
 */
int
parsehexfsid(const char *hex, fsid_t *fsid)
{
        char hexbuf[3];
        int i;

        if (strlen(hex) != sizeof(*fsid) * 2)
                return (-1);
        hexbuf[2] = '\0';
        for (i = 0; i < (int)sizeof(*fsid); i++) {
                hexbuf[0] = hex[i * 2];
                hexbuf[1] = hex[i * 2 + 1];
                if (!isxdigit(hexbuf[0]) || !isxdigit(hexbuf[1]))
                        return (-1);
                ((u_char *)fsid)[i] = strtol(hexbuf, NULL, 16);
        }
        return (0);
}

/*
 * xdr routines for mount rpc's
 */
int
xdr_dir(XDR *xdrsp, char *dirp)
{

        return (xdr_string(xdrsp, &dirp, MNTPATHLEN));
}

void
usage(void)
{

        (void)fprintf(stderr, "%s\n%s\n",
            "usage: umount [-dfNnv] special ... | node ... | fsid ...",
            "       umount -a | -A [-F fstab] [-dfnv] [-h host] [-t type]");
        exit(1);
}

int
md_detach(const char *device)
{
        struct md_ioctl mdio;
        char *eptr;
        int fd;

        if (strncmp(device, DEV_MD, sizeof(DEV_MD) - 1)) {
                if (!all)
                        warnx("invalid md device: %s", device);
                return (-1);
        }

        memset(&mdio, 0, sizeof(mdio));
        mdio.md_version = MDIOVERSION;
        mdio.md_options = fflag ? MD_FORCE : 0;
        mdio.md_unit = strtoul(device + sizeof(DEV_MD) - 1, &eptr, 0);
        if (mdio.md_unit == (unsigned)ULONG_MAX || eptr - device == sizeof(DEV_MD) - 1) {
                warnx("invalid md device: %s", device);
                return (-1);
        }

        fd = open(DEV_MDCTL, O_RDWR, 0);
        if (fd < 0) {
                warn("%s", DEV_MDCTL);
                return (-1);
        }

        if (ioctl(fd, MDIOCDETACH, &mdio) < 0) {
                warn("%s", DEV_MD);
                close(fd);
                return (-1);
        }

        close(fd);
        return (0);
}