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, gflg, 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:gmno:pqrvVO")) != -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':
                Fflg++;
                Farg = optarg;
                break;
            case 'g':
                gflg++;
                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 (gflg)
        newargv[ii++] = "-g";
    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 == NULL)
        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 (gflg)
        newargv[i++] = "-g";
    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;

    if (vp->rpath)
        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);
}