/*
 * 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 2009 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#include <sys/types.h>
#include <sys/param.h>
#include <sys/errno.h>

#ifdef _KERNEL
#include <sys/sunddi.h>
#include <fs/fs_reparse.h>
#else
#include <string.h>
#include <limits.h>
#include <sys/fs_reparse.h>

#define strfree(str)            free((str))
#endif

static char *reparse_skipspace(char *cp);
static int reparse_create_nvlist(const char *string, nvlist_t *nvl);
static int reparse_add_nvpair(char *token, nvlist_t *nvl);
static boolean_t reparse_validate_svctype(char *svc_str);
static int reparse_validate_create_nvlist(const char *string, nvlist_t *nvl);

/* array of characters not allowed in service type string */
static char svctype_invalid_chars[] = { '{', '}', 0 };

/*
 * reparse_init()
 *
 * Function to allocate a new name-value pair list.
 * Caller needs to call reparse_free() to free memory
 * used by the list when done.
 *
 * Return pointer to new list else return NULL.
 */
nvlist_t *
reparse_init(void)
{
        nvlist_t *nvl;

        /*
         * Service type is unique, only one entry
         * of each service type is allowed
         */
        if (nvlist_alloc(&nvl, NV_UNIQUE_NAME, 0))
                return (NULL);

        return (nvl);
}

/*
 * reparse_free()
 *
 * Function to free memory of a nvlist allocated previously
 * by reparse_init().
 */
void
reparse_free(nvlist_t *nvl)
{
        nvlist_free(nvl);
}

/*
 * reparse_parse()
 *
 * Parse the specified string and populate the nvlist with the svc_types
 * and data from the 'string'.  The string could be read from the reparse
 * point symlink body. This routine will allocate memory that must be
 * freed by reparse_free().
 *
 * If ok return 0 and the nvlist is populated, otherwise return error code.
 */
int
reparse_parse(const char *string, nvlist_t *nvl)
{
        int err;

        if (string == NULL || nvl == NULL)
                return (EINVAL);

        if ((err = reparse_validate(string)) != 0)
                return (err);

        if ((err = reparse_create_nvlist(string, nvl)) != 0)
                return (err);

        return (0);
}

static char *
reparse_skipspace(char *cp)
{
        while ((*cp) && (*cp == ' ' || *cp == '\t'))
                cp++;
        return (cp);
}

static boolean_t
reparse_validate_svctype(char *svc_str)
{
        int nx, ix, len;

        if (svc_str == NULL)
                return (B_FALSE);

        len = strlen(svc_str);
        for (ix = 0; ix < len; ix++) {
                for (nx = 0; nx < sizeof (svctype_invalid_chars); nx++) {
                        if (svc_str[ix] == svctype_invalid_chars[nx])
                                return (B_FALSE);
                }
        }
        return (B_TRUE);
}

static boolean_t
reparse_validate_svc_token(char *svc_token)
{
        char save_c, *cp;

        if (svc_token == NULL)
                return (B_FALSE);
        if ((cp = strchr(svc_token, ':')) == NULL)
                return (B_FALSE);

        save_c = *cp;
        *cp = '\0';

        /*
         * make sure service type and service data are non-empty string.
         */
        if (strlen(svc_token) == 0 || strlen(cp + 1) == 0) {
                *cp = save_c;
                return (B_FALSE);
        }

        *cp = save_c;
        return (B_TRUE);
}

/*
 * Format of reparse data:
 * @{REPARSE@{servicetype:data} [@{servicetype:data}] ...}
 * REPARSE_TAG_STR@{REPARSE_TOKEN} [@{REPARSE_TOKEN}] ... REPARSE_TAG_END
 *
 * Validating reparse data:
 *      . check for valid length of reparse data
 *      . check for valid reparse data format
 * Return 0 if OK else return error code.
 */
int
reparse_validate(const char *string)
{
        return (reparse_validate_create_nvlist(string, NULL));
}

/*
 * reparse_validate_create_nvlist
 *
 * dual-purpose function:
 *     . Validate a reparse data string.
 *     . Validate a reparse data string and parse the data
 *       into a nvlist.
 */
static int
reparse_validate_create_nvlist(const char *string, nvlist_t *nvl)
{
        int err, tcnt;
        char *reparse_data, save_c, save_e, *save_e_ptr, *cp, *s_str, *e_str;

        if (string == NULL)
                return (EINVAL);

        if (strlen(string) >= MAXREPARSELEN)
                return (ENAMETOOLONG);

        if ((reparse_data = strdup(string)) == NULL)
                return (ENOMEM);

        /* check FS_REPARSE_TAG_STR */
        if (strncmp(reparse_data, FS_REPARSE_TAG_STR,
            strlen(FS_REPARSE_TAG_STR))) {
                strfree(reparse_data);
                return (EINVAL);
        }

        /* locate FS_REPARSE_TAG_END_CHAR */
        if ((cp = strrchr(reparse_data, FS_REPARSE_TAG_END_CHAR)) == NULL) {
                strfree(reparse_data);
                return (EINVAL);
        }
        save_e = *cp;
        save_e_ptr = cp;
        *cp = '\0';

        e_str = cp;
        cp++;           /* should point to NULL, or spaces */

        cp = reparse_skipspace(cp);
        if (*cp) {
                *save_e_ptr = save_e;
                strfree(reparse_data);
                return (EINVAL);
        }

        /* skip FS_REPARSE_TAG_STR */
        s_str = reparse_data + strlen(FS_REPARSE_TAG_STR);

        /* skip spaces after FS_REPARSE_TAG_STR */
        s_str = reparse_skipspace(s_str);

        tcnt = 0;
        while (s_str < e_str) {
                /* check FS_TOKEN_START_STR */
                if (strncmp(s_str, FS_TOKEN_START_STR,
                    strlen(FS_TOKEN_START_STR))) {
                        *save_e_ptr = save_e;
                        strfree(reparse_data);
                        return (EINVAL);
                }

                /* skip over FS_TOKEN_START_STR */
                s_str += strlen(FS_TOKEN_START_STR);

                /* locate FS_TOKEN_END_STR */
                if ((cp = strstr(s_str, FS_TOKEN_END_STR)) == NULL) {
                        *save_e_ptr = save_e;
                        strfree(reparse_data);
                        return (EINVAL);
                }

                tcnt++;
                save_c = *cp;
                *cp = '\0';

                /* check for valid characters in service type */
                if (reparse_validate_svctype(s_str) == B_FALSE) {
                        *cp = save_c;
                        *save_e_ptr = save_e;
                        strfree(reparse_data);
                        return (EINVAL);
                }

                if (strlen(s_str) == 0) {
                        *cp = save_c;
                        *save_e_ptr = save_e;
                        strfree(reparse_data);
                        return (EINVAL);
                }

                if (reparse_validate_svc_token(s_str) == B_FALSE) {
                        *cp = save_c;
                        *save_e_ptr = save_e;
                        strfree(reparse_data);
                        return (EINVAL);
                }

                /* create a nvpair entry */
                if (nvl != NULL &&
                    (err = reparse_add_nvpair(s_str, nvl)) != 0) {
                        *cp = save_c;
                        *save_e_ptr = save_e;
                        strfree(reparse_data);
                        return (err);
                }

                *cp = save_c;

                /* skip over FS_TOKEN_END_STR */
                cp += strlen(FS_TOKEN_END_STR);
                cp = reparse_skipspace(cp);
                s_str = cp;
        }
        *save_e_ptr = save_e;
        strfree(reparse_data);

        return (tcnt ? 0 : EINVAL);
}

static int
reparse_add_nvpair(char *token, nvlist_t *nvl)
{
        int err;
        char save_c, *cp;

        if ((cp = strchr(token, ':')) == NULL)
                return (EINVAL);

        save_c = *cp;
        *cp = '\0';
        err = nvlist_add_string(nvl, token, cp + 1);
        *cp = save_c;

        return (err);
}

static int
reparse_create_nvlist(const char *string, nvlist_t *nvl)
{
        if (nvl == NULL)
                return (EINVAL);

        return (reparse_validate_create_nvlist(string, nvl));
}