Merge commit 'ad3ad82ad2fb99c424a8482bd1908d08b990ccea'

[unleashed.git] / usr / src / cmd / fs.d / mount.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (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 2015 Nexenta Systems, Inc.  All rights reserved.
 */

/*      Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
/*        All Rights Reserved   */


/*
 * Copyright 2010 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#include        <stdio.h>
#include        <stdio_ext.h>
#include        <limits.h>
#include        <fcntl.h>
#include        <unistd.h>
#include        <stdlib.h>
#include        <string.h>
#include        <stdarg.h>
#include        <sys/types.h>
#include        <sys/stat.h>
#include        <sys/statvfs.h>
#include        <errno.h>
#include        <sys/mnttab.h>
#include        <sys/mntent.h>
#include        <sys/mount.h>
#include        <sys/vfstab.h>
#include        <sys/param.h>
#include        <sys/wait.h>
#include        <sys/signal.h>
#include        <sys/resource.h>
#include        <stropts.h>
#include        <sys/conf.h>
#include        <locale.h>
#include        "fslib.h"

#define VFS_PATH        "/usr/lib/fs"
#define ALT_PATH        "/etc/fs"
#define REMOTE          "/etc/dfs/fstypes"

#define ARGV_MAX        16
#define TIME_MAX        50
#define FSTYPE_MAX      8
#define REMOTE_MAX      64

#define OLD     0
#define NEW     1

#define READONLY        0
#define READWRITE       1
#define SUID            2
#define NOSUID          3
#define SETUID          4
#define NOSETUID        5
#define DEVICES         6
#define NODEVICES       7

#define FORMAT  "%a %b %e %H:%M:%S %Y\n"        /* date time format */
                                /* a - abbreviated weekday name */
                                /* b - abbreviated month name */
                                /* e - day of month */
                                /* H - hour */
                                /* M - minute */
                                /* S - second */
                                /* Y - Year */
                                /* n - newline */

/*
 * The fs-local method understands this exit code to mean that one or
 * more failures occurred and that all the failures were of attempted
 * lofs mounts.
 */
#define ALL_LOFS_FAILURES       111

extern int      optind;
extern char     *optarg;

extern void     usage(void);
extern char     *flags(char *, int);
extern char     *remote(char *, FILE *);
extern char     *default_fstype(char *);

char    *myopts[] = {
        MNTOPT_RO,
        MNTOPT_RW,
        MNTOPT_SUID,
        MNTOPT_NOSUID,
        MNTOPT_SETUID,
        MNTOPT_NOSETUID,
        MNTOPT_DEVICES,
        MNTOPT_NODEVICES,
        NULL
};

static char     *myname;                /* point to argv[0] */

/*
 * Set the limit to double the number of characters a user should be allowed to
 * type in one line.
 * This should cover the different shells, which don't use POSIX_MAX_INPUT,
 * and should cover the case where a long option string can be in
 * the /etc/vfstab file.
 */
char    mntflags[(_POSIX_MAX_INPUT+1) * 2];

char    realdir[MAXPATHLEN];    /* buffer for realpath() calls */
char    *vfstab = VFSTAB;
char    *mnttab = MNTTAB;
char    *specific_opts;         /* holds specific mount options */
char    *generic_opts;          /* holds generic mount options */
int     maxrun;
int     nrun;
int     failcnt;                /* total count of failures */
int     lofscnt;                /* presence of lofs prohibits parallel */
                                /* mounting */
int     lofsfail;               /* count of failures of lofs mounts */
int     exitcode;
int     aflg, cflg, fflg, Fflg, oflg, pflg, rflg, vflg, Vflg, mflg, Oflg,
        dashflg, questflg, dflg, qflg;


/*
 * Each vfsent_t describes a vfstab entry.  It is used to manage and cleanup
 * each child that performs the particular mount for the entry.
 */

typedef struct vfsent {
        struct vfstab   v;              /* the vfstab entry */
        char            *rpath;         /* resolved pathname so far */
        int             mlevel;         /* how deep is this mount point */
        int             order;          /* vfstab serial order of this vfs */
        int             flag;
        pid_t           pid;            /* the pid of this mount process */
        int             exitcode;       /* process's exitcode */
#define RDPIPE          0
#define WRPIPE          1
        int             sopipe[2];      /* pipe attached to child's stdout */
        int             sepipe[2];      /* pipe attached to child's stderr */
        struct vfsent   *next;          /* used when in linked list */
} vfsent_t;

#define VRPFAILED       0x01            /* most recent realpath failed on */
                                        /* this mount point */
#define VNOTMOUNTED     0x02            /* mount point could not be mounted */

vfsent_t        *vfsll, *vfslltail;     /* head and tail of the global */
                                        /* linked list of vfstab entries */
vfsent_t        **vfsarray;             /* global array of vfsent_t's */
int             vfsarraysize;           /* length of the list */

/*
 * This structure is used to build a linked list of
 * mnttab structures from /etc/mnttab.
 */
typedef struct mountent {
        struct extmnttab        *ment;
        int             flag;
        struct mountent *next;
} mountent_t;

#define MSORTED         0x1

static vfsent_t **make_vfsarray(char **, int);
static vfsent_t *new_vfsent(struct vfstab *, int);
static vfsent_t *getvfsall(char *, int);

static void     doexec(char *, char **);
static void     nomem();
static void     cleanup(int);
static char     *setrpath(vfsent_t *);
static int      dowait();
static int      setup_iopipe(vfsent_t *);
static void     setup_output(vfsent_t *);
static void     doio(vfsent_t *);
static void     do_mounts();
static int      parmount(char **, int, char *);
static int      mlevelcmp(const void *, const void *);
static int      mordercmp(const void *, const void *);
static int      check_fields(char *, char *);
static int      cleanupkid(pid_t, int);
static void     print_mnttab(int, int);
static void     vfserror(int, char *);
static void     mnterror(int);
static int      ignore(char *);

/*
 * This is /usr/sbin/mount: the generic command that in turn
 * execs the appropriate /usr/lib/fs/{fstype}/mount.
 * The -F flag and argument are NOT passed.
 * If the usr file system is not mounted a duplicate copy
 * can be found in /sbin and this version execs the
 * appropriate /etc/fs/{fstype}/mount
 *
 * If the -F fstype, special or directory are missing,
 * /etc/vfstab is searched to fill in the missing arguments.
 *
 * -V will print the built command on the stdout.
 * It isn't passed either.
 */
int
main(int argc, char *argv[])
{
        char    *special,       /* argument of special/resource */
            *mountp,            /* argument of mount directory */
            *fstype,            /* wherein the fstype name is filled */
            *newargv[ARGV_MAX], /* arg list for specific command */
            *farg = NULL, *Farg = NULL;
        int     ii, ret, cc, fscnt;
        struct stat64   stbuf;
        struct vfstab   vget, vref;
        mode_t mode;
        FILE    *fd;

        (void) setlocale(LC_ALL, "");

#if !defined(TEXT_DOMAIN)
#define TEXT_DOMAIN "SYS_TEST"
#endif
        (void) textdomain(TEXT_DOMAIN);

        myname = strrchr(argv[0], '/');
        if (myname)
                myname++;
        else
                myname = argv[0];
        if (myname == 0) myname = "path unknown";

        /* Process the args.  */

        while ((cc = getopt(argc, argv, "?acd:f:F:mno:pqrt:vVO")) != -1)
                switch (cc) {
                        case 'a':
                                aflg++;
                                break;
                        case 'c':
                                cflg++;
                                break;

#ifdef DEBUG
                        case 'd':
                                dflg = atoi(optarg);
                                break;
#endif

                        case 'f':
                                fflg++;
                                farg = optarg;
                                break;
                        case 'F':
                        case 't':
                                Fflg++;
                                Farg = optarg;
                                break;
                        case 'm':
                                mflg++;
                                break; /* do not update /etc/mnttab */
                        case 'o':
                                oflg++;
                                if ((specific_opts = strdup(optarg)) == NULL)
                                        nomem();
                                break; /* fstype dependent options */
                        case 'O':
                                Oflg++;
                                break;
                        case 'p':
                                pflg++;
                                break;
                        case 'q':
                                qflg++;
                                break;
                        case 'r':
                                rflg++;
                                generic_opts = "ro";
                                break;
                        case 'v':
                                vflg++;
                                break;
                        case 'V':
                                Vflg++;
                                break;
                        case '?':
                                questflg++;
                                break;
                }

        /* copy '--' to specific */
        if (strcmp(argv[optind-1], "--") == 0)
                dashflg++;

        /* option checking */
        /* more than two args not allowed if !aflg */
        if (!aflg && (argc - optind > 2))
                usage();

        /* pv mututally exclusive */
        if (pflg + vflg + aflg > 1) {
                fprintf(stderr, gettext
                    ("%s: -a, -p, and -v are mutually exclusive\n"),
                    myname);
                usage();
        }

        /*
         * Can't have overlaying mounts on the same mount point during
         * a parallel mount.
         */
        if (aflg && Oflg) {
                fprintf(stderr, gettext
                    ("%s: -a and -O are mutually exclusive\n"), myname);
                usage();
        }

        /* dfF mutually exclusive */
        if (fflg + Fflg > 1) {
                fprintf(stderr, gettext
                    ("%s: More than one FSType specified\n"), myname);
                usage();
        }

        /* no arguments, only allow p,v,V or [F]? */
        if (!aflg && optind == argc) {
                if (cflg || fflg || mflg || oflg || rflg || qflg)
                        usage();

                if (Fflg && !questflg)
                        usage();

                if (questflg) {
                        if (Fflg) {
                                newargv[2] = "-?";
                                newargv[3] = NULL;
                                doexec(Farg, newargv);
                        }
                        usage();
                }
        }

        if (questflg)
                usage();

        /* one or two args, allow any but p,v */
        if (optind != argc && (pflg || vflg)) {
                fprintf(stderr,
gettext("%s: Cannot use -p and -v with arguments\n"), myname);
                usage();
        }


        /* if only reporting mnttab, generic prints mnttab and exits */
        if (!aflg && optind == argc) {
                if (Vflg) {
                        printf("%s", myname);
                        if (pflg)
                                printf(" -p");
                        if (vflg)
                                printf(" -v");
                        printf("\n");
                        exit(0);
                }

                print_mnttab(vflg, pflg);
                exit(0);
        }

        /*
         * Get filesystem type here.  If "-F FStype" is specified, use
         * that fs type.  Otherwise, determine the fs type from /etc/vfstab
         * if the entry exists.  Otherwise, determine the local or remote
         * fs type from /etc/default/df or /etc/dfs/fstypes respectively.
         */
        if (fflg) {
                if ((strcmp(farg, "S51K") != 0) &&
                    (strcmp(farg, "S52K") != 0)) {
                        fstype = farg;
                }
                else
                        fstype = "ufs";
        } else /* if (Fflg) */
                fstype = Farg;

        fscnt = argc - optind;
        if (aflg && (fscnt != 1))
                exit(parmount(argv + optind, fscnt, fstype));

        /*
         * Then don't bother with the parallel over head.  Everything
         * from this point is simple/normal single execution.
         */
        aflg = 0;

        /* get special and/or mount-point from arg(s) */
        if (fscnt == 2)
                special = argv[optind++];
        else
                special = NULL;
        if (optind < argc)
                mountp = argv[optind++];
        else
                mountp = NULL;

        /* lookup only if we need to */
        if (fstype == NULL || specific_opts == NULL || special == NULL ||
            mountp == NULL) {
                if ((fd = fopen(vfstab, "r")) == NULL) {
                        if (fstype == NULL || special == NULL ||
                            mountp == NULL) {
                                fprintf(stderr, gettext(
                                    "%s: Cannot open %s\n"),
                                    myname, vfstab);
                                exit(1);
                        } else {
                                /*
                                 * No vfstab, but we know what we want
                                 * to mount.
                                 */
                                goto out;
                        }
                }
                vfsnull(&vref);
                vref.vfs_special = special;
                vref.vfs_mountp = mountp;
                vref.vfs_fstype = fstype;

                /* get a vfstab entry matching mountp or special */
                while ((ret = getvfsany(fd, &vget, &vref)) > 0)
                        vfserror(ret, vget.vfs_special);

                /* if no entry and there was only one argument */
                /* then the argument could be the special */
                /* and not mount point as we thought earlier */
                if (ret == -1 && special == NULL) {
                        rewind(fd);
                        special = vref.vfs_special = mountp;
                        mountp = vref.vfs_mountp = NULL;
                        /* skip erroneous lines; they were reported above */
                        while ((ret = getvfsany(fd, &vget, &vref)) > 0)
                                ;
                }

                fclose(fd);

                if (ret == 0) {
                        if (fstype == NULL)
                                fstype = vget.vfs_fstype;
                        if (special == NULL)
                                special = vget.vfs_special;
                        if (mountp == NULL)
                                mountp = vget.vfs_mountp;
                        if (oflg == 0 && vget.vfs_mntopts) {
                                oflg++;
                                specific_opts = vget.vfs_mntopts;
                        }
                } else if (special == NULL) {
                        if (stat64(mountp, &stbuf) == -1) {
                                fprintf(stderr, gettext("%s: cannot stat %s\n"),
                                    myname, mountp);
                                exit(2);
                        }
                        if (((mode = (stbuf.st_mode & S_IFMT)) == S_IFBLK) ||
                            (mode == S_IFCHR)) {
                                fprintf(stderr,
gettext("%s: mount point cannot be determined\n"),
                                    myname);
                                exit(1);
                        } else
                                {
                                fprintf(stderr,
gettext("%s: special cannot be determined\n"),
                                    myname);
                                exit(1);
                        }
                } else if (fstype == NULL)
                        fstype = default_fstype(special);
        }

out:
        if (realpath(mountp, realdir) == NULL) {
                (void) fprintf(stderr, "mount: ");
                perror(mountp);
                exit(1);
        }

        if ((mountp = strdup(realdir)) == NULL)
                nomem();

        if (check_fields(fstype, mountp))
                exit(1);

        /* create the new arg list, and end the list with a null pointer */
        ii = 2;
        if (cflg)
                newargv[ii++] = "-c";
        if (mflg)
                newargv[ii++] = "-m";
        /*
         * The q option needs to go before the -o option as some
         * filesystems complain during first pass option parsing.
         */
        if (qflg)
                newargv[ii++] = "-q";
        if (oflg) {
                newargv[ii++] = "-o";
                newargv[ii++] = specific_opts;
        }
        if (Oflg)
                newargv[ii++] = "-O";
        if (rflg)
                newargv[ii++] = "-r";
        if (dashflg)
                newargv[ii++] = "--";
        newargv[ii++] = special;
        newargv[ii++] = mountp;
        newargv[ii] = NULL;

        doexec(fstype, newargv);
        return (0);
}

void
usage(void)
{
        fprintf(stderr, gettext("Usage:\n%s [-v | -p]\n"), myname);
        fprintf(stderr, gettext(
            "%s [-F FSType] [-V] [current_options] [-o specific_options]"),
            myname);
        fprintf(stderr, gettext("\n\t{special | mount_point}\n"));

        fprintf(stderr, gettext(
            "%s [-F FSType] [-V] [current_options] [-o specific_options]"),
            myname);
        fprintf(stderr, gettext("\n\tspecial mount_point\n"));

        fprintf(stderr, gettext(
        "%s -a [-F FSType ] [-V] [current_options] [-o specific_options]\n"),
            myname);
        fprintf(stderr, gettext("\t[mount_point ...]\n"));

        exit(1);
}

/*
 * Get rid of "dev=[hex string]" clause, if any.  It's not legal
 * when printing in vfstab format.
 */
void
elide_dev(char *mntopts)
{
        char *dev, *other;

        if (mntopts != NULL) {
                dev = strstr(mntopts, "dev=");
                if (dev != NULL) {
                        other = strpbrk(dev, ",");
                        if (other == NULL) {
                                /* last option */
                                if (dev != mntopts) {
                                        *--dev = '\0';
                                } else {
                                        *dev = '\0';
                                }
                        } else {
                                /* first or intermediate option */
                                memmove(dev, other+1, strlen(other+1)+1);
                        }
                }
        }
}

void
print_mnttab(int vflg, int pflg)
{
        FILE    *fd;
        FILE    *rfp;                   /* this will be NULL if fopen fails */
        int     ret;
        char    time_buf[TIME_MAX];     /* array to hold date and time */
        struct extmnttab        mget;
        time_t  ltime;

        if ((fd = fopen(mnttab, "r")) == NULL) {
                fprintf(stderr, gettext("%s: Cannot open mnttab\n"), myname);
                exit(1);
        }
        rfp = fopen(REMOTE, "r");
        while ((ret = getextmntent(fd, &mget, sizeof (struct extmnttab)))
            == 0) {
                if (ignore(mget.mnt_mntopts))
                        continue;
                if (mget.mnt_special && mget.mnt_mountp &&
                    mget.mnt_fstype && mget.mnt_time) {
                        ltime = atol(mget.mnt_time);
                        cftime(time_buf, FORMAT, &ltime);
                        if (pflg) {
                                elide_dev(mget.mnt_mntopts);
                                printf("%s - %s %s - no %s\n",
                                    mget.mnt_special,
                                    mget.mnt_mountp,
                                    mget.mnt_fstype,
                                    mget.mnt_mntopts != NULL ?
                                    mget.mnt_mntopts : "-");
                        } else if (vflg) {
                                printf("%s on %s type %s %s%s on %s",
                                    mget.mnt_special,
                                    mget.mnt_mountp,
                                    mget.mnt_fstype,
                                    remote(mget.mnt_fstype, rfp),
                                    flags(mget.mnt_mntopts, NEW),
                                    time_buf);
                        } else
                                printf("%s on %s %s%s on %s",
                                    mget.mnt_mountp,
                                    mget.mnt_special,
                                    remote(mget.mnt_fstype, rfp),
                                    flags(mget.mnt_mntopts, OLD),
                                    time_buf);
                }
        }
        if (ret > 0)
                mnterror(ret);
}

char    *
flags(char *mntopts, int flag)
{
        char    opts[sizeof (mntflags)];
        char    *value;
        int     rdwr = 1;
        int     suid = 1;
        int     devices = 1;
        int     setuid = 1;

        if (mntopts == NULL || *mntopts == '\0')
                return ("read/write/setuid/devices");

        strcpy(opts, "");
        while (*mntopts != '\0')  {
                switch (getsubopt(&mntopts, myopts, &value)) {
                case READONLY:
                        rdwr = 0;
                        break;
                case READWRITE:
                        rdwr = 1;
                        break;
                case SUID:
                        suid = 1;
                        break;
                case NOSUID:
                        suid = 0;
                        break;
                case SETUID:
                        setuid = 1;
                        break;
                case NOSETUID:
                        setuid = 0;
                        break;
                case DEVICES:
                        devices = 1;
                        break;
                case NODEVICES:
                        devices = 0;
                        break;
                default:
                        /* cat '/' separator to mntflags */
                        if (*opts != '\0' && value != NULL)
                                strcat(opts, "/");
                        strcat(opts, value);
                        break;
                }
        }

        strcpy(mntflags, "");
        if (rdwr)
                strcat(mntflags, "read/write");
        else if (flag == OLD)
                strcat(mntflags, "read only");
        else
                strcat(mntflags, "read-only");
        if (suid) {
                if (setuid)
                        strcat(mntflags, "/setuid");
                else
                        strcat(mntflags, "/nosetuid");
                if (devices)
                        strcat(mntflags, "/devices");
                else
                        strcat(mntflags, "/nodevices");
        } else {
                strcat(mntflags, "/nosetuid/nodevices");
        }
        if (*opts != '\0') {
                strcat(mntflags, "/");
                strcat(mntflags, opts);
        }

        /*
         * The assumed assertion
         *      assert (strlen(mntflags) < sizeof mntflags);
         * is valid at this point in the code. Note that a call to "assert"
         * is not appropriate in production code since it halts the program.
         */
        return (mntflags);
}

char    *
remote(char *fstype, FILE *rfp)
{
        char    buf[BUFSIZ];
        char    *fs;
        extern char *strtok();

        if (rfp == NULL || fstype == NULL ||
            strlen(fstype) > (size_t)FSTYPE_MAX)
                return ("");    /* not a remote */
        rewind(rfp);
        while (fgets(buf, sizeof (buf), rfp) != NULL) {
                fs = strtok(buf, " \t\n");
                if (strcmp(fstype, fs) == 0)
                        return ("remote/");     /* is a remote fs */
        }
        return ("");    /* not a remote */
}


void
vfserror(int flag, char *special)
{
        if (special == NULL)
                special = "<null>";
        switch (flag) {
        case VFS_TOOLONG:
                fprintf(stderr,
gettext("%s: Warning: Line in vfstab for \"%s\" exceeds %d characters\n"),
                    myname, special, VFS_LINE_MAX-1);
                break;
        case VFS_TOOFEW:
                fprintf(stderr,
gettext("%s: Warning: Line for \"%s\" in vfstab has too few entries\n"),
                    myname, special);
                break;
        case VFS_TOOMANY:
                fprintf(stderr,
gettext("%s: Warning: Line for \"%s\" in vfstab has too many entries\n"),
                    myname, special);
                break;
        default:
                fprintf(stderr, gettext(
                    "%s: Warning: Error in line for \"%s\" in vfstab\n"),
                    myname, special);
        }
}

void
mnterror(int flag)
{
        switch (flag) {
        case MNT_TOOLONG:
                fprintf(stderr,
                    gettext("%s: Line in mnttab exceeds %d characters\n"),
                    myname, MNT_LINE_MAX-2);
                break;
        case MNT_TOOFEW:
                fprintf(stderr,
                    gettext("%s: Line in mnttab has too few entries\n"),
                    myname);
                break;
        case MNT_TOOMANY:
                fprintf(stderr,
                    gettext("%s: Line in mnttab has too many entries\n"),
                    myname);
                break;
        }
        exit(1);
}

void
doexec(char *fstype, char *newargv[])
{
        char    full_path[PATH_MAX];
        char    alter_path[PATH_MAX];
        char    *vfs_path = VFS_PATH;
        char    *alt_path = ALT_PATH;
        int     i;

        /* build the full pathname of the fstype dependent command. */
        sprintf(full_path, "%s/%s/%s", vfs_path, fstype, myname);
        sprintf(alter_path, "%s/%s/%s", alt_path, fstype, myname);
        newargv[1] = myname;

        if (Vflg) {
                printf("%s -F %s", newargv[1], fstype);
                for (i = 2; newargv[i]; i++)
                        printf(" %s", newargv[i]);
                printf("\n");
                fflush(stdout);
                exit(0);
        }

        /*
         * Try to exec the fstype dependent portion of the mount.
         * See if the directory is there before trying to exec dependent
         * portion.  This is only useful for eliminating the
         * '..mount: not found' message when '/usr' is mounted
         */
        if (access(full_path, 0) == 0) {
                execv(full_path, &newargv[1]);
                if (errno == EACCES) {
                        fprintf(stderr,
                        gettext("%s: Cannot execute %s - permission denied\n"),
                            myname, full_path);
                }
                if (errno == ENOEXEC) {
                        newargv[0] = "sh";
                        newargv[1] = full_path;
                        execv("/sbin/sh", &newargv[0]);
                }
        }
        execv(alter_path, &newargv[1]);
        if (errno == EACCES) {
                fprintf(stderr, gettext(
                    "%s: Cannot execute %s - permission denied\n"),
                    myname, alter_path);
                exit(1);
        }
        if (errno == ENOEXEC) {
                newargv[0] = "sh";
                newargv[1] = alter_path;
                execv("/sbin/sh", &newargv[0]);
        }
        fprintf(stderr,
            gettext("%s: Operation not applicable to FSType %s\n"),
            myname, fstype);
        exit(1);
}

char *mntopts[] = { MNTOPT_IGNORE, NULL };
#define IGNORE    0

/*
 * Return 1 if "ignore" appears in the options string
 */
int
ignore(char *opts)
{
        char *value;
        char *saveptr, *my_opts;
        int rval = 0;

        if (opts == NULL || *opts == '\0')
                return (0);

        /*
         * we make a copy of the option string to pass to getsubopt(),
         * because getsubopt() modifies the string.  We also save
         * the original pointer returned by strdup, because getsubopt
         * changes the pointer passed into it.  If strdup fails (unlikely),
         * we act as if the "ignore" option isn't set rather than fail.
         */

        if ((saveptr = my_opts = strdup(opts)) == NULL)
                nomem();

        while (*my_opts != '\0') {
                if (getsubopt(&my_opts, mntopts, &value) == IGNORE)
                        rval = 1;
        }

        free(saveptr);

        return (rval);
}

/*
 * Perform the parallel version of mount.  If count == 0, mount all
 * vfstab filesystems with the automnt field == "yes".  Use fstype if
 * supplied.  If mntlist supplied, then attempt to only mount those.
 */

int
parmount(char **mntlist, int count, char *fstype)
{
        int             maxfd = OPEN_MAX;
        struct          rlimit rl;
        vfsent_t        **vl, *vp;

        /*
         * Process scaling.  After running a series
         * of tests based on the number of simultaneous processes and
         * processors available, optimum performance was achieved near or
         * at (PROCN * 2).
         */
        if ((maxrun = sysconf(_SC_NPROCESSORS_ONLN)) == -1)
                maxrun = 4;
        else
                maxrun = maxrun * 2 + 1;

        if (getrlimit(RLIMIT_NOFILE, &rl) == 0) {
                rl.rlim_cur = rl.rlim_max;
                if (setrlimit(RLIMIT_NOFILE, &rl) == 0)
                        maxfd = (int)rl.rlim_cur;
        }
        (void) enable_extended_FILE_stdio(-1, -1);

        /*
         * The parent needs to maintain 3 of its own fd's, plus 2 for
         * each child (the stdout and stderr pipes).
         */
        maxfd = (maxfd / 2) - 6;        /* 6 takes care of temporary  */
                                        /* periods of open fds */
        if (maxfd < maxrun)
                maxrun = maxfd;
        if (maxrun < 4)
                maxrun = 4;             /* sanity check */

        if (count == 0)
                mntlist = NULL;         /* used as a flag later */
        else
                fstype = NULL;          /* mount points supplied: */
                                        /* ignore fstype */
        /*
         * Read the whole vfstab into a linked list for quick processing.
         * On average, this is the most efficient way to collect and
         * manipulate the vfstab data.
         */
        vfsll = getvfsall(fstype, mntlist == NULL);

        /*
         * Make an array out of the vfs linked list for sorting purposes.
         */
        if (vfsll == NULL ||
            (vfsarray = make_vfsarray(mntlist, count)) == NULL) {
                if (mntlist == NULL)    /* not an error - just none found */
                        return (0);

                fprintf(stderr, gettext("%s: No valid entries found in %s\n"),
                    myname, vfstab);
                return (1);
        }

        /*
         * Sort the entries based on their resolved path names
         *
         * If an lofs is encountered, then the original order of the vfstab
         * file needs to be maintained until we are done mounting lofs's.
         */
        if (!lofscnt)
                qsort((void *)vfsarray, vfsarraysize, sizeof (vfsent_t *),
                    mlevelcmp);

        /*
         * Shrink the vfsll linked list down to the new list.  This will
         * speed up the pid search in cleanupkid() later.
         */
        vfsll = vfsarray[0];
        for (vl = vfsarray; vp = *vl; )
                vp->next = *++vl;

        /*
         * Try to handle interrupts in a reasonable way.
         */
        sigset(SIGHUP, cleanup);
        sigset(SIGQUIT, cleanup);
        sigset(SIGINT, cleanup);

        do_mounts();            /* do the mounts */

        if (failcnt > 0 && failcnt == lofsfail)
                return (ALL_LOFS_FAILURES);

        return (exitcode);
}

/*
 * Read all vstab (fp) entries into memory if fstype == NULL.
 * If fstype is specified, than read all those that match it.
 *
 * Returns a linked list.
 */
vfsent_t *
getvfsall(char *fstype, int takeall)
{
        vfsent_t        *vhead, *vtail;
        struct vfstab   vget;
        FILE            *fp;
        int             cnt = 0, ret;

        if ((fp = fopen(vfstab, "r")) == NULL) {
                fprintf(stderr, gettext("%s: Cannot open %s\n"),
                    myname, vfstab);
                exit(1);
        }

        vhead = vtail = NULL;

        while ((ret = getvfsent(fp, &vget)) != -1) {
                vfsent_t *vp;

                if (ret > 0) {
                        vfserror(ret, vget.vfs_mountp);
                        continue;
                }

                /*
                 * If mount points were not specified, then we ignore
                 * entries that aren't marked "yes".
                 */
                if (takeall &&
                    (vget.vfs_automnt == NULL ||
                    strcmp(vget.vfs_automnt, "yes")))
                        continue;

                if (fstype && vget.vfs_fstype &&
                    strcmp(fstype, vget.vfs_fstype))
                        continue;

                if (vget.vfs_mountp == NULL ||
                    (vget.vfs_fstype && (strcmp(vget.vfs_fstype, "swap") == 0)))
                        continue;

                if (check_fields(vget.vfs_fstype, vget.vfs_mountp)) {
                        exitcode = 1;
                        continue;
                }

                vp = new_vfsent(&vget, cnt);    /* create new vfs entry */
                if (vhead == NULL)
                        vhead = vp;
                else
                        vtail->next = vp;
                vtail = vp;
                cnt++;
        }
        fclose(fp);
        if (vtail == NULL) {
                vfsarraysize = 0;
                vfslltail = NULL;
                return (NULL);
        }
        vtail->next = NULL;
        vfslltail = vtail;      /* save it in the global variable */
        vfsarraysize = cnt;
        return (vhead);
}


/*
 * Returns an array of vfsent_t's based on vfsll & mntlist.
 */
vfsent_t **
make_vfsarray(char **mntlist, int count)
{
        vfsent_t        *vp, *vmark, *vpprev, **vpp;
        int             ndx, found;

        if (vfsll == NULL)
                return (NULL);

        if (count > 0)
                vfsarraysize = count;

        vpp = (vfsent_t **)malloc(sizeof (*vpp) * (vfsarraysize + 1));
        if (vpp == NULL)
                nomem();

        if (mntlist == NULL) {
                /*
                 * No mount list specified: take all vfstab mount points.
                 */
                for (ndx = 0, vp = vfsll; vp; vp = vp->next) {
                        (void) setrpath(vp);
                        /*
                         * Sigh. lofs entries can complicate matters so much
                         * that the best way to avoid problems is to
                         * stop parallel mounting when an lofs is
                         * encountered, so we keep a count of how many
                         * there are.
                         * Fortunately this is rare.
                         */
                        if (vp->v.vfs_fstype &&
                            (strcmp(vp->v.vfs_fstype, MNTTYPE_LOFS) == 0))
                                lofscnt++;

                        vpp[ndx++] = vp;
                }
                vpp[ndx] = NULL;
                return (vpp);
        }

        /*
         * A list of mount points was specified on the command line
         * and we need to search for each one.
         */
        vpprev = vfslltail;
        vpprev->next = vfsll;   /* make a circle out of it */
        vmark = vp = vfsll;
        /*
         * For each specified mount point:
         */
        for (ndx = 0; *mntlist; mntlist++) {
                found = 0;
                /*
                 * Circle our entire linked list, looking for *mntlist.
                 */
                while (vp) {
                        if (strcmp(*mntlist, vp->v.vfs_mountp) == 0) {
                                vpp[ndx++] = vp;        /* found it. */
                                (void) setrpath(vp);
                                if (vp->v.vfs_fstype &&
                                    (strcmp(vp->v.vfs_fstype,
                                    MNTTYPE_LOFS) == 0))
                                        lofscnt++;

                                if (vp == vpprev) {     /* list exhausted */
                                        vp = NULL;
                                        found++;
                                        break;
                                }
                                /*
                                 * Remove it from the circular list.  vpprev
                                 * remains unchanged.
                                 */
                                vp = vp->next;
                                vpprev->next->next = NULL;
                                vpprev->next = vp;
                                /*
                                 * Set vmark to the first elem that we check
                                 * each time.
                                 */
                                vmark = vp;
                                found++;
                                break;
                        }
                        vpprev = vp;
                        vp = vp->next;
                        if (vp == vmark)        /* break out if we completed */
                                                /* the circle */
                                break;
                }

                if (!found) {
                        fprintf(stderr, gettext(
                            "%s: Warning: %s not found in %s\n"),
                            myname, *mntlist, vfstab);
                        exitcode = 1;
                }
        }
        if (ndx == 0)
                return (NULL);

        vpp[ndx] = NULL;        /* null terminate the list */
        vfsarraysize = ndx;     /* adjust vfsarraysize */
        return (vpp);
}

/*
 * Performs the exec argument processing, all  of the child forking and
 * execing, and child cleanup.
 * Sets exitcode to non-zero if any errors occurred.
 */
void
do_mounts(void)
{
        int             i, isave, cnt;
        vfsent_t        *vp, *vpprev, **vl;
        char            *newargv[ARGV_MAX];
        pid_t           child;

        /*
         * create the arg list once;  the only differences among
         * the calls are the options, special and mountp fields.
         */
        i = 2;
        if (cflg)
                newargv[i++] = "-c";
        if (mflg)
                newargv[i++] = "-m";
        if (Oflg)
                newargv[i++] = "-O";
        if (qflg)
                newargv[i++] = "-q";
        if (rflg)
                newargv[i++] = "-r";
        if (dashflg)
                newargv[i++] = "--";
        if (oflg) {
                newargv[i++] = "-o";
                newargv[i++] = specific_opts;
        }
        isave = i;

        /*
         * Main loop for the mount processes
         */
        vl = vfsarray;
        cnt = vfsarraysize;
        for (vpprev = *vl; vp = *vl; vpprev = vp, vl++, cnt--) {
                /*
                 * Check to see if we cross a mount level: e.g.,
                 * /a/b -> /a/b/c.  If so, we need to wait for all current
                 * mounts to finish, rerun realpath on the remaining mount
                 * points, and resort the list.
                 *
                 * Also, we mount serially as long as there are lofs's
                 * to mount to avoid improper mount ordering.
                 */
                if (vp->mlevel > vpprev->mlevel || lofscnt > 0) {
                        vfsent_t **vlp;

                        while (nrun > 0 && (dowait() != -1))
                                ;
                        /*
                         * Gads! It's possible for real path mounts points to
                         * change after mounts are done at a lower mount
                         * level.
                         * Thus, we need to recalculate mount levels and
                         * resort the list from this point.
                         */
                        for (vlp = vl; *vlp; vlp++)
                                (void) setrpath(*vlp);
                        /*
                         * Sort the remaining entries based on their newly
                         * resolved path names.
                         * Do not sort if we still have lofs's to mount.
                         */
                        if (lofscnt == 0) {
                                qsort((void *)vl, cnt, sizeof (vfsent_t *),
                                    mlevelcmp);
                                vp = *vl;
                        }
                }

                if (vp->flag & VRPFAILED) {
                        fprintf(stderr, gettext(
                            "%s: Nonexistent mount point: %s\n"),
                            myname, vp->v.vfs_mountp);
                        vp->flag |= VNOTMOUNTED;
                        exitcode = 1;
                        continue;
                }

                /*
                 * If mount options were not specified on the command
                 * line, then use the ones found in the vfstab entry,
                 * if any.
                 */
                i = isave;
                if (!oflg && vp->v.vfs_mntopts) {
                        newargv[i++] = "-o";
                        newargv[i++] = vp->v.vfs_mntopts;
                }
                newargv[i++] = vp->v.vfs_special;
                newargv[i++] = vp->rpath;
                newargv[i] = NULL;

                /*
                 * This should never really fail.
                 */
                while (setup_iopipe(vp) == -1 && (dowait() != -1))
                        ;

                while (nrun >= maxrun && (dowait() != -1))      /* throttle */
                        ;

                if ((child = fork()) == -1) {
                        perror("fork");
                        cleanup(-1);
                        /* not reached */
                }
                if (child == 0) {               /* child */
                        signal(SIGHUP, SIG_IGN);
                        signal(SIGQUIT, SIG_IGN);
                        signal(SIGINT, SIG_IGN);
                        setup_output(vp);
                        doexec(vp->v.vfs_fstype, newargv);
                        perror("exec");
                        exit(1);
                }

                /* parent */
                (void) close(vp->sopipe[WRPIPE]);
                (void) close(vp->sepipe[WRPIPE]);
                vp->pid = child;
                nrun++;
        }
        /*
         * Mostly done by now - wait and clean up the stragglers.
         */
        cleanup(0);
}


/*
 * Setup stdout and stderr pipes for the children's output.
 */
int
setup_iopipe(vfsent_t *mp)
{
        /*
         * Make a stdout and stderr pipe.  This should never fail.
         */
        if (pipe(mp->sopipe) == -1)
                return (-1);
        if (pipe(mp->sepipe) == -1) {
                (void) close(mp->sopipe[RDPIPE]);
                (void) close(mp->sopipe[WRPIPE]);
                return (-1);
        }
        /*
         * Don't block on an empty pipe.
         */
        (void) fcntl(mp->sopipe[RDPIPE], F_SETFL, O_NDELAY|O_NONBLOCK);
        (void) fcntl(mp->sepipe[RDPIPE], F_SETFL, O_NDELAY|O_NONBLOCK);
        /*
         * Don't pass extra fds into children.
         */
        (void) fcntl(mp->sopipe[RDPIPE], F_SETFD, FD_CLOEXEC);
        (void) fcntl(mp->sepipe[RDPIPE], F_SETFD, FD_CLOEXEC);

        return (0);
}

/*
 * Called by a child to attach its stdout and stderr to the write side of
 * the pipes.
 */
void
setup_output(vfsent_t *vp)
{

        (void) close(fileno(stdout));
        (void) dup(vp->sopipe[WRPIPE]);
        (void) close(vp->sopipe[WRPIPE]);

        (void) close(fileno(stderr));
        (void) dup(vp->sepipe[WRPIPE]);
        (void) close(vp->sepipe[WRPIPE]);
}

/*
 * Parent uses this to print any stdout or stderr output issued by
 * the child.
 */
static void
doio(vfsent_t *vp)
{
        int bytes;
        char ibuf[BUFSIZ];

        while ((bytes = read(vp->sepipe[RDPIPE], ibuf, sizeof (ibuf))) > 0)
                write(fileno(stderr), ibuf, bytes);
        while ((bytes = read(vp->sopipe[RDPIPE], ibuf, sizeof (ibuf))) > 0)
                write(fileno(stdout), ibuf, bytes);

        (void) close(vp->sopipe[RDPIPE]);
        (void) close(vp->sepipe[RDPIPE]);
}

/*
 * Waits for 1 child to die.
 *
 * Returns -1 if no children are left to wait for.
 * Returns 0 if a child died without an error.
 * Returns 1 if a child died with an error.
 */
int
dowait(void)
{
        int child, wstat;

        if ((child = wait(&wstat)) == -1)
                return (-1);
        nrun--;
        return (cleanupkid(child, wstat) != 0);
}

/*
 * Locates the child mount process represented by pid, outputs any io
 * it may have, and returns its exit code.
 * Sets the global exitcode if an error occurred.
 */
int
cleanupkid(pid_t pid, int wstat)
{
        vfsent_t *vp, *prevp;
        int ret;

        if (WIFEXITED(wstat))           /* this should always be true */
                ret = WEXITSTATUS(wstat);
        else
                ret = 1;                /* assume some kind of error */
        if (ret) {
                exitcode = 1;
                failcnt++;
        }

        /*
         * Find our child.
         * This search gets smaller and smaller as children are cleaned
         * up.
         */
        for (prevp = NULL, vp = vfsll; vp; vp = vp->next) {
                if (vp->pid != pid) {
                        prevp = vp;
                        continue;
                }
                /*
                 * Found: let's remove it from this linked list.
                 */
                if (prevp) {
                        prevp->next = vp->next;
                        vp->next = NULL;
                }
                break;
        }

        if (vp == NULL) {
                /*
                 * This should never happen.
                 */
                fprintf(stderr, gettext(
                    "%s: Unknown child %d\n"), myname, pid);
                exitcode = 1;
                return (ret);
        }
        doio(vp);       /* Any output? */

        if (vp->v.vfs_fstype &&
            (strcmp(vp->v.vfs_fstype, MNTTYPE_LOFS) == 0)) {
                lofscnt--;
                if (ret)
                        lofsfail++;
        }

        vp->exitcode = ret;
        return (ret);
}


static vfsent_t zvmount = { 0 };

vfsent_t *
new_vfsent(struct vfstab *vin, int order)
{
        vfsent_t *new;

        new = (vfsent_t *)malloc(sizeof (*new));
        if (new == NULL)
                nomem();

        *new = zvmount;
        if (vin->vfs_special &&
            (new->v.vfs_special = strdup(vin->vfs_special)) == NULL)
                nomem();
        if (vin->vfs_mountp &&
            (new->v.vfs_mountp = strdup(vin->vfs_mountp)) == NULL)
                nomem();
        if (vin->vfs_fstype &&
            (new->v.vfs_fstype = strdup(vin->vfs_fstype)) == NULL)
                nomem();
        /*
         * If specific mount options were specified on the command
         * line, then use those.  Else, use the ones on the vfstab
         * line, if any.  In other words, specific options on the
         * command line override those in /etc/vfstab.
         */
        if (oflg) {
                if ((new->v.vfs_mntopts = strdup(specific_opts)) == NULL)
                        nomem();
        } else if (vin->vfs_mntopts &&
            (new->v.vfs_mntopts = strdup(vin->vfs_mntopts)) == NULL)
                        nomem();

        new->order = order;
        return (new);
}

/*
 * Runs realpath on vp's mount point, records success or failure,
 * resets the mount level based on the new realpath, and returns
 * realpath()'s return value.
 */
char *
setrpath(vfsent_t *vp)
{
        char *rp;

        if ((rp = realpath(vp->v.vfs_mountp, realdir)) == NULL)
                vp->flag |= VRPFAILED;
        else
                vp->flag &= ~VRPFAILED;

        free(vp->rpath);
        if ((vp->rpath = strdup(realdir)) == NULL)
                nomem();
        vp->mlevel = fsgetmlevel(vp->rpath);
        return (rp);
}


/*
 * sort first by mlevel (1...N), then by vfstab order.
 */
int
mlevelcmp(const void *a, const void *b)
{
        vfsent_t *a1, *b1;
        int     lcmp;

        a1 = *(vfsent_t **)a;
        b1 = *(vfsent_t **)b;

        lcmp = a1->mlevel - b1->mlevel;
        if (lcmp == 0)
                lcmp = a1->order - b1->order;
        return (lcmp);
}

/* sort by vfstab order.  0..N */
static int
mordercmp(const void *a, const void *b)
{
        vfsent_t *a1, *b1;

        a1 = *(vfsent_t **)a;
        b1 = *(vfsent_t **)b;
        return (a1->order - b1->order);
}

/*
 * cleanup the existing children and exit with an error
 * if asig != 0.
 */
void
cleanup(int asig)
{
        while (nrun > 0 && (dowait() != -1))
                ;

        if (asig != 0)
                exit(1);
}


int
check_fields(char *fstype, char *mountp)
{
        struct stat64 stbuf;

        if (fstype == NULL) {
                fprintf(stderr,
                    gettext("%s: FSType cannot be determined\n"),
                    myname);
                return (1);
        }
        if (strlen(fstype) > (size_t)FSTYPE_MAX) {
                fprintf(stderr,
                    gettext("%s: FSType %s exceeds %d characters\n"),
                    myname, fstype, FSTYPE_MAX);
                return (1);
        }

        if (mountp == NULL) {
                fprintf(stderr,
                    gettext("%s: Mount point cannot be determined\n"),
                    myname);
                return (1);
        }
        if (*mountp != '/') {
                fprintf(stderr, gettext(
                    "%s: Mount point %s is not an absolute pathname.\n"),
                    myname, mountp);
                return (1);
        }
        /*
         * Don't do some of these checks if aflg because a mount point may
         * not exist now, but will be mounted before we get to it.
         * This is one of the quirks of "secondary mounting".
         */
        if (!aflg && stat64(mountp, &stbuf) < 0) {
                if (errno == ENOENT || errno == ENOTDIR)
                        fprintf(stderr,
                            gettext("%s: Mount point %s does not exist.\n"),
                            myname, mountp);
                else {
                        fprintf(stderr,
                            gettext("%s: Cannot stat mount point %s.\n"),
                            myname, mountp);
                        perror(myname);
                }
                return (1);
        }
        return (0);
}

void
nomem(void)
{
        fprintf(stderr, gettext("%s: Out of memory\n"), myname);
        while (nrun > 0 && (dowait() != -1))
                ;
        exit(1);
}