5868 Make checks in inet_matchaddr() more robust

[unleashed.git] / usr / src / cmd / fs.d / fslib.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 2008 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#pragma ident   "%Z%%M% %I%     %E% SMI"

#include        <stdio.h>
#include        <stdarg.h>
#include        <stdlib.h>
#include        <unistd.h>
#include        <libintl.h>
#include        <string.h>
#include        <fcntl.h>
#include        <errno.h>
#include        <syslog.h>
#include        <alloca.h>
#include        <sys/vfstab.h>
#include        <sys/mnttab.h>
#include        <sys/mntent.h>
#include        <sys/mount.h>
#include        <sys/filio.h>
#include        <sys/fs/ufs_filio.h>
#include        <sys/stat.h>
#include        <sys/param.h>
#include        <zone.h>
#include        <signal.h>
#include        <strings.h>
#include        "fslib.h"

/* LINTLIBRARY */

#define BUFLEN          256

#define TIME_MAX 16

/*
 * Reads all of the entries from the in-kernel mnttab, and returns the
 * linked list of the entries.
 */
mntlist_t *
fsgetmntlist(void)
{
        FILE *mfp;
        mntlist_t *mntl;
        char buf[BUFLEN];

        if ((mfp = fopen(MNTTAB, "r")) == NULL) {
                (void) snprintf(buf, BUFLEN, "fsgetmntlist: fopen %s", MNTTAB);
                perror(buf);
                return (NULL);
        }

        mntl = fsmkmntlist(mfp);

        (void) fclose(mfp);
        return (mntl);
}


static struct extmnttab zmnttab = { 0 };

struct extmnttab *
fsdupmnttab(struct extmnttab *mnt)
{
        struct extmnttab *new;

        new = (struct extmnttab *)malloc(sizeof (*new));
        if (new == NULL)
                goto alloc_failed;

        *new = zmnttab;
        /*
         * Allocate an extra byte for the mountpoint
         * name in case a space needs to be added.
         */
        new->mnt_mountp = (char *)malloc(strlen(mnt->mnt_mountp) + 2);
        if (new->mnt_mountp == NULL)
                goto alloc_failed;
        (void) strcpy(new->mnt_mountp, mnt->mnt_mountp);

        if ((new->mnt_special = strdup(mnt->mnt_special)) == NULL)
                goto alloc_failed;

        if ((new->mnt_fstype = strdup(mnt->mnt_fstype)) == NULL)
                goto alloc_failed;

        if (mnt->mnt_mntopts != NULL)
                if ((new->mnt_mntopts = strdup(mnt->mnt_mntopts)) == NULL)
                        goto alloc_failed;

        if (mnt->mnt_time != NULL)
                if ((new->mnt_time = strdup(mnt->mnt_time)) == NULL)
                        goto alloc_failed;

        new->mnt_major = mnt->mnt_major;
        new->mnt_minor = mnt->mnt_minor;
        return (new);

alloc_failed:
        (void) fprintf(stderr, gettext("fsdupmnttab: Out of memory\n"));
        fsfreemnttab(new);
        return (NULL);
}

/*
 * Free a single mnttab structure
 */
void
fsfreemnttab(struct extmnttab *mnt)
{

        if (mnt) {
                if (mnt->mnt_special)
                        free(mnt->mnt_special);
                if (mnt->mnt_mountp)
                        free(mnt->mnt_mountp);
                if (mnt->mnt_fstype)
                        free(mnt->mnt_fstype);
                if (mnt->mnt_mntopts)
                        free(mnt->mnt_mntopts);
                if (mnt->mnt_time)
                        free(mnt->mnt_time);
                free(mnt);
        }
}

void
fsfreemntlist(mntlist_t *mntl)
{
        mntlist_t *mntl_tmp;

        while (mntl) {
                fsfreemnttab(mntl->mntl_mnt);
                mntl_tmp = mntl;
                mntl = mntl->mntl_next;
                free(mntl_tmp);
        }
}

/*
 * Read the mnttab file and return it as a list of mnttab structs.
 * Returns NULL if there was a memory failure.
 */
mntlist_t *
fsmkmntlist(FILE *mfp)
{
        struct extmnttab        mnt;
        mntlist_t       *mhead, *mtail;
        int             ret;

        mhead = mtail = NULL;

        resetmnttab(mfp);
        while ((ret = getextmntent(mfp, &mnt, sizeof (struct extmnttab)))
            != -1) {
                mntlist_t       *mp;

                if (ret != 0)           /* bad entry */
                        continue;

                mp = (mntlist_t *)malloc(sizeof (*mp));
                if (mp == NULL)
                        goto alloc_failed;
                if (mhead == NULL)
                        mhead = mp;
                else
                        mtail->mntl_next = mp;
                mtail = mp;
                mp->mntl_next = NULL;
                mp->mntl_flags = 0;
                if ((mp->mntl_mnt = fsdupmnttab(&mnt)) == NULL)
                        goto alloc_failed;
        }
        return (mhead);

alloc_failed:
        fsfreemntlist(mhead);
        return (NULL);
}

/*
 * Return the last entry that matches mntin's special
 * device and/or mountpt.
 * Helps to be robust here, so we check for NULL pointers.
 */
mntlist_t *
fsgetmlast(mntlist_t *ml, struct mnttab *mntin)
{
        mntlist_t       *delete = NULL;

        for (; ml; ml = ml->mntl_next) {
                if (mntin->mnt_mountp && mntin->mnt_special) {
                        /*
                         * match if and only if both are equal.
                         */
                        if ((strcmp(ml->mntl_mnt->mnt_mountp,
                            mntin->mnt_mountp) == 0) &&
                            (strcmp(ml->mntl_mnt->mnt_special,
                            mntin->mnt_special) == 0))
                                delete = ml;
                } else if (mntin->mnt_mountp) {
                        if (strcmp(ml->mntl_mnt->mnt_mountp,
                            mntin->mnt_mountp) == 0)
                                delete = ml;
                } else if (mntin->mnt_special) {
                        if (strcmp(ml->mntl_mnt->mnt_special,
                            mntin->mnt_special) == 0)
                                delete = ml;
                }
        }
        return (delete);
}


/*
 * Returns the mountlevel of the pathname in cp.  As examples,
 * / => 1, /bin => 2, /bin/ => 2, ////bin////ls => 3, sdf => 0, etc...
 */
int
fsgetmlevel(char *cp)
{
        int     mlevel;
        char    *cp1;

        if (cp == NULL || *cp == NULL || *cp != '/')
                return (0);     /* this should never happen */

        mlevel = 1;                     /* root (/) is the minimal case */

        for (cp1 = cp + 1; *cp1; cp++, cp1++)
                if (*cp == '/' && *cp1 != '/')  /* "///" counts as 1 */
                        mlevel++;

        return (mlevel);
}

/*
 * Returns non-zero if string s is a member of the strings in ps.
 */
int
fsstrinlist(const char *s, const char **ps)
{
        const char *cp;
        cp = *ps;
        while (cp) {
                if (strcmp(s, cp) == 0)
                        return (1);
                ps++;
                cp = *ps;
        }
        return (0);
}

static char *empty_opt_vector[] = {
        NULL
};
/*
 * Compare the mount options that were requested by the caller to
 * the options actually supported by the file system.  If any requested
 * options are not supported, print a warning message.
 *
 * WARNING: this function modifies the string pointed to by
 *      the requested_opts argument.
 *
 * Arguments:
 *      requested_opts - the string containing the requested options.
 *      actual_opts - the string returned by mount(2), which lists the
 *              options actually supported.  It is normal for this
 *              string to contain more options than the requested options.
 *              (The actual options may contain the default options, which
 *              may not have been included in the requested options.)
 *      special - device being mounted (only used in error messages).
 *      mountp - mount point (only used in error messages).
 */
void
cmp_requested_to_actual_options(char *requested_opts, char *actual_opts,
        char *special, char *mountp)
{
        char    *option_ptr, *actopt, *equalptr;
        int     found;
        char    *actual_opt_hold, *bufp;

        if (requested_opts == NULL)
                return;

        bufp = alloca(strlen(actual_opts) + 1);

        while (*requested_opts != '\0') {
                (void) getsubopt(&requested_opts, empty_opt_vector,
                    &option_ptr);

                /*
                 * Truncate any "=<value>" string from the end of
                 * the option.
                 */
                if ((equalptr = strchr(option_ptr, '=')) != NULL)
                        *equalptr = '\0';

                if (*option_ptr == '\0')
                        continue;

                /*
                 * Whilst we don't need this option to perform a lofi
                 * mount, let's not be mendacious enough to complain
                 * about it.
                 */
                if (strcmp(option_ptr, "loop") == 0)
                        continue;

                /*
                 * Search for the requested option in the list of options
                 * actually supported.
                 */
                found = 0;

                /*
                 * Need to use a copy of actual_opts because getsubopt
                 * is destructive and we need to scan the actual_opts
                 * string more than once.
                 *
                 * We also need to reset actual_opt_hold to the
                 * beginning of the buffer because getsubopt changes
                 * actual_opt_hold (the pointer).
                 */
                actual_opt_hold = bufp;
                if (actual_opts != NULL)
                        (void) strcpy(actual_opt_hold, actual_opts);
                else
                        *actual_opt_hold = '\0';

                while (*actual_opt_hold != '\0') {
                        (void) getsubopt(&actual_opt_hold, empty_opt_vector,
                            &actopt);

                        /* Truncate the "=<value>", if any. */
                        if ((equalptr = strchr(actopt, '=')) != NULL)
                                *equalptr = '\0';

                        if ((strcmp(option_ptr, actopt)) == 0) {
                                found = 1;
                                break;
                        }
                }

                if (found == 0) {
                        /*
                         * That we're ignoring the option is always
                         * truthful; the old message that the option
                         * was unknown is often not correct.
                         */
                        (void) fprintf(stderr, gettext(
                            "mount: %s on %s - WARNING ignoring option "
                            "\"%s\"\n"), special, mountp, option_ptr);
                }
        }
}
/*
 * FUNCTION:    fsgetmaxphys(int *, int *)
 *
 * INPUT:       int *maxphys - a pointer to an integer that will hold
 *                      the value for the system maxphys value.
 *              int *error - 0 means completed successfully
 *                           otherwise this indicates the errno value.
 *
 * RETURNS:     int     - 0 if maxphys not found
 *                      - 1 if maxphys is found
 */
int
fsgetmaxphys(int *maxphys, int *error) {

        int     gotit = 0;
        int     fp = open("/", O_RDONLY);

        *error = 0;

        /*
         * For some reason cannot open root as read only. Need a valid file
         * descriptor to call the ufs private ioctl. If this open failes,
         * just assume we cannot get maxphys in this case.
         */
        if (fp == -1) {
                return (gotit);
        }

        if (ioctl(fp, _FIOGETMAXPHYS, maxphys) == -1) {
                *error = errno;
                (void) close(fp);
                return (gotit);
        }

        (void) close(fp);
        gotit = 1;
        return (gotit);

}

/*
 * The below is limited support for zone-aware commands.
 */
struct zone_summary {
        zoneid_t        zoneid;
        char            rootpath[MAXPATHLEN];
        size_t          rootpathlen;
};

struct zone_summary *
fs_get_zone_summaries(void)
{
        uint_t numzones = 0, oldnumzones = 0;
        uint_t i, j;
        zoneid_t *ids = NULL;
        struct zone_summary *summaries;
        zoneid_t myzoneid = getzoneid();

        for (;;) {
                if (zone_list(ids, &numzones) < 0) {
                        perror("unable to retrieve list of zones");
                        if (ids != NULL)
                                free(ids);
                        return (NULL);
                }
                if (numzones <= oldnumzones)
                        break;
                if (ids != NULL)
                        free(ids);
                ids = malloc(numzones * sizeof (*ids));
                if (ids == NULL) {
                        perror("malloc failed");
                        return (NULL);
                }
                oldnumzones = numzones;
        }

        summaries = malloc((numzones + 1) * sizeof (*summaries));
        if (summaries == NULL) {
                free(ids);
                perror("malloc failed");
                return (NULL);
        }


        for (i = 0, j = 0; i < numzones; i++) {
                ssize_t len;

                if (ids[i] == myzoneid)
                        continue;
                len = zone_getattr(ids[i], ZONE_ATTR_ROOT,
                    summaries[j].rootpath, sizeof (summaries[j].rootpath));
                if (len < 0) {
                        /*
                         * Zone must have gone away. Skip.
                         */
                        continue;
                }
                /*
                 * Adding a trailing '/' to the zone's rootpath allows us to
                 * use strncmp() to see if a given path resides within that
                 * zone.
                 *
                 * As an example, if the zone's rootpath is "/foo/root",
                 * "/foo/root/usr" resides within the zone, while
                 * "/foo/rootpath" doesn't.
                 */
                (void) strlcat(summaries[j].rootpath, "/",
                    sizeof (summaries[j].rootpath));
                summaries[j].rootpathlen = len;
                summaries[j].zoneid = ids[i];
                j++;
        }
        summaries[j].zoneid = -1;
        free(ids);
        return (summaries);
}

static zoneid_t
fs_find_zone(const struct zone_summary *summaries, const char *mntpt)
{
        uint_t i;

        for (i = 0; summaries[i].zoneid != -1; i++) {
                if (strncmp(mntpt, summaries[i].rootpath,
                    summaries[i].rootpathlen) == 0)
                        return (summaries[i].zoneid);
        }
        /*
         * (-1) is the special token we return to the caller if the mount
         * wasn't found in any other mounts on the system.  This means it's
         * only visible to our zone.
         *
         * Odd choice of constant, I know, but it beats calling getzoneid() a
         * million times.
         */
        return (-1);
}

boolean_t
fs_mount_in_other_zone(const struct zone_summary *summaries, const char *mntpt)
{
        return (fs_find_zone(summaries, mntpt) != -1);
}

/*
 * List of standard options.
 */
static const char *stdopts[] = {
        MNTOPT_RO,                      MNTOPT_RW,
        MNTOPT_SUID,                    MNTOPT_NOSUID,
        MNTOPT_DEVICES,                 MNTOPT_NODEVICES,
        MNTOPT_SETUID,                  MNTOPT_NOSETUID,
        MNTOPT_NBMAND,                  MNTOPT_NONBMAND,
        MNTOPT_EXEC,                    MNTOPT_NOEXEC,
};

#define NSTDOPT         (sizeof (stdopts) / sizeof (stdopts[0]))

static int
optindx(const char *opt)
{
        int i;

        for (i = 0; i < NSTDOPT; i++) {
                if (strcmp(opt, stdopts[i]) == 0)
                        return (i);
        }
        return (-1);
}

/*
 * INPUT:       filesystem option not recognized by the fs specific option
 *              parsing code.
 * OUTPUT:      True if and only if the option is one of the standard VFS
 *              layer options.
 */
boolean_t
fsisstdopt(const char *opt)
{
        return (optindx(opt) != -1);
}