common/zfs/zfs_namecheck.c

	zfs_namecheck.c revision fa9e4066f08beec538e775443c5be79dd423fcab
/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (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 2005 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

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

/*
 * Common name validation routines for ZFS.  These routines are shared by the
 * userland code as well as the ioctl() layer to ensure that we don't
 * inadvertently expose a hole through direct ioctl()s that never gets tested.
 * In userland, however, we want significantly more information about _why_ the
 * name is invalid.  In the kernel, we only care whether it's valid or not.
 * Each routine therefore takes a 'namecheck_err_t' which describes exactly why
 * the name failed to validate.
 *
 * Each function returns 0 on success, -1 on error.
 */

#if defined(_KERNEL)
#include <sys/systm.h>
#else
#include <string.h>
#endif

#include "zfs_namecheck.h"

static int
valid_char(char c)
{
    return ((c >= 'a' && c <= 'z') ||
        (c >= 'A' && c <= 'Z') ||
        (c >= '0' && c <= '9') ||
        c == '-' || c == '_' || c == '.' || c == ':');
}

/*
 * Dataset names must be of the following form:
 *
 *  [component][/]*[component][@component]
 *
 * Where each component is made up of alphanumeric characters plus the following
 * characters:
 *
 *  [-_.:]
 */
int
dataset_namecheck(const char *path, namecheck_err_t *why, char *what)
{
    const char *loc, *end;
    int found_snapshot;

    /* Explicitly check for a leading slash.  */
    if (path[0] == '/') {
        if (why)
            *why = NAME_ERR_LEADING_SLASH;
        return (-1);
    }

    if (path[0] == '\0') {
        if (why)
            *why = NAME_ERR_EMPTY_COMPONENT;
        return (-1);
    }

    loc = path;
    found_snapshot = 0;
    for (;;) {
        /* Find the end of this component */
        end = loc;
        while (*end != '/' && *end != '@' && *end != '\0')
            end++;

        if (*end == '\0' && end[-1] == '/') {
            /* trailing slashes are not allowed */
            if (why)
                *why = NAME_ERR_TRAILING_SLASH;
            return (-1);
        }

        /* Zero-length components are not allowed */
        if (loc == end) {
            if (why)
                *why = NAME_ERR_EMPTY_COMPONENT;
            return (-1);
        }

        /* Validate the contents of this component */
        while (loc != end) {
            if (!valid_char(*loc)) {
                if (why) {
                    *why = NAME_ERR_INVALCHAR;
                    *what = *loc;
                }
                return (-1);
            }
            loc++;
        }

        /* If we've reached the end of the string, we're OK */
        if (*end == '\0')
            return (0);

        if (*end == '@') {
            /*
             * If we've found an @ symbol, indicate that we're in
             * the snapshot component, and report a second '@'
             * character as an error.
             */
            if (found_snapshot) {
                if (why)
                    *why = NAME_ERR_MULTIPLE_AT;
                return (-1);
            }

            found_snapshot = 1;
        }

        /* Update to the next component */
        loc = end + 1;
    }
}

/*
 * For pool names, we have the same set of valid characters as described in
 * dataset names, with the additional restriction that the pool name must begin
 * with a letter.  The pool names 'raidz' and 'mirror' are also reserved names
 * that cannot be used.
 */
int
pool_namecheck(const char *pool, namecheck_err_t *why, char *what)
{
    const char *c;

    c = pool;
    while (*c != '\0') {
        if (!valid_char(*c)) {
            if (why) {
                *why = NAME_ERR_INVALCHAR;
                *what = *c;
            }
            return (-1);
        }
        c++;
    }

    if (!(*pool >= 'a' && *pool <= 'z') &&
        !(*pool >= 'A' && *pool <= 'Z')) {
        if (why)
            *why = NAME_ERR_NOLETTER;
        return (-1);
    }

    if (strcmp(pool, "mirror") == 0 || strcmp(pool, "raidz") == 0) {
        if (why)
            *why = NAME_ERR_RESERVED;
        return (-1);
    }

    if (pool[0] == 'c' && (pool[1] >= '0' && pool[1] <= '9')) {
        if (why)
            *why = NAME_ERR_DISKLIKE;
        return (-1);
    }

    return (0);
}

/*
 * Check if the dataset name is private for internal usage.
 * '$' is reserved for internal dataset names. e.g. "$MOS"
 *
 * Return 1 if the given name is used internally.
 * Return 0 if it is not.
 */
int
dataset_name_hidden(const char *name)
{
    if (strchr(name, '$') != NULL)
        return (1);

    return (0);
}