/*
 * 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 (c) 2010, Oracle and/or its affiliates. All rights reserved.
 */

#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <libintl.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/stat.h>

#include "bblk_einfo.h"
#include "boot_utils.h"

bblk_hash_t     bblk_no_hash = {BBLK_NO_HASH, 0, "(no hash)", NULL};
bblk_hash_t     bblk_md5_hash = {BBLK_HASH_MD5, 0x10, "MD5", md5_calc};

bblk_hash_t     *bblk_hash_list[BBLK_HASH_TOT] = {
        &bblk_no_hash,
        &bblk_md5_hash
};

/*
 * einfo_compare_dotted_version()
 * Compares two strings with an arbitrary long number of dot-separated numbers.
 * Returns:     0  - if the version numbers are equal
 *              1  - if str1 version number is more recent than str2
 *              2  - if str2 version number is more recent than str1
 *              -1 - if an error occurred
 *
 * Comparison is done field by field, by retrieving an unsigned integer value,
 * (missing fields are assumed as 0, but explict zeroes take precedence) so:
 *   4.1.2.11 > 4.1.2.2 > 4.1.2.0 > 4.1.2
 *
 * where ">" means "more recent than".
 */
static int
einfo_compare_dotted_version(const char *str1, const char *str2)
{
        int             retval = 0;
        char            *verstr1, *verstr2, *freeptr1, *freeptr2;
        char            *parsep1, *parsep2;
        unsigned int    val_str1, val_str2;

        freeptr1 = verstr1 = strdup(str1);
        freeptr2 = verstr2 = strdup(str2);
        if (verstr1 == NULL || verstr2 == NULL) {
                retval = -1;
                goto out;
        }

        while (verstr1 != NULL && verstr2 != NULL) {
                parsep1 = strsep(&verstr1, ".");
                parsep2 = strsep(&verstr2, ".");

                val_str1 = atoi(parsep1);
                val_str2 = atoi(parsep2);

                if (val_str1 > val_str2) {
                        retval = 1;
                        goto out;
                }

                if (val_str2 > val_str1) {
                        retval = 2;
                        goto out;
                }
        }

        /* Common portion of the version string is equal. */
        if (verstr1 == NULL && verstr2 != NULL)
                retval = 2;
        if (verstr2 == NULL && verstr1 != NULL)
                retval = 1;

out:
        free(freeptr1);
        free(freeptr2);
        return (retval);
}

/*
 * einfo_compare_timestamps()
 * Currently, timestamp is in %Y%m%dT%H%M%SZ format in UTC, which means that
 * we can simply do a lexicographic comparison to know which one is the most
 * recent.
 *
 * Returns:   0  - if timestamps coincide
 *            1  - if the timestamp in str1 is more recent
 *            2  - if the timestamp in str2 is more recent
 */
static int
einfo_compare_timestamps(const char *str1, const char *str2)
{
        int     retval;

        retval = strcmp(str1, str2);
        if (retval > 0)
                retval = 1;
        if (retval < 0)
                retval = 2;

        return (retval);
}

/*
 * einfo_compare_version()
 * Given two extended versions, compare the two and returns which one is more
 * "recent". Comparison is based on dotted version number fields and a
 * timestamp.
 *
 * Returns:    -1   - on error
 *              0   - if the two versions coincide
 *              1   - if the version in str1 is more recent
 *              2   - if the version in str2 is more recent
 *
 * The version string generally uses following form:
 *     self_release,build_release:timestamp
 * The release numbers are compared as dotted versions.
 *
 * While comparing, if the self releases are identical but the build
 * release is missing, this version string is considered older.
 *
 * If the release strings are identical, and one of the timestamps is missing,
 * we return an error. Otherwise, return the result from comparing the
 * timestamps.
 */
static int
einfo_compare_version(const char *str1, const char *str2)
{
        int     retval = 0;
        char    *verstr1, *verstr2, *freeptr1, *freeptr2;
        char    *parsep1, *parsep2;
        char    *timep1, *timep2;

        freeptr1 = verstr1 = strdup(str1);
        freeptr2 = verstr2 = strdup(str2);
        if (verstr1 == NULL || verstr2 == NULL) {
                retval = -1;
                goto out;
        }

        /* Extract the time part from the version string. */
        timep1 = verstr1;
        timep2 = verstr2;
        parsep1 = strsep(&timep1, ":");
        parsep2 = strsep(&timep2, ":");

        while (parsep1 != NULL && parsep2 != NULL) {
                parsep1 = strsep(&verstr1, ",-");
                parsep2 = strsep(&verstr2, ",-");

                /* If both are NULL, compare timestamps */
                if (parsep1 == NULL && parsep2 == NULL)
                        break;

                if (parsep1 == NULL) {
                        retval = 2;
                        goto out;
                }
                if (parsep2 == NULL) {
                        retval = 1;
                        goto out;
                }

                retval = einfo_compare_dotted_version(parsep1, parsep2);
                if (retval == 0)
                        continue;
                else
                        goto out;
        }

        /* The dotted versions are identical, check timestamps. */
        if (timep1 == NULL || timep2 == NULL) {
                retval = -1;
                goto out;
        }
        retval = einfo_compare_timestamps(timep1, timep2);
out:
        free(freeptr1);
        free(freeptr2);
        return (retval);
}

/*
 * print_einfo()
 *
 * Print the extended information contained into the pointed structure.
 * 'bufsize' specifies the real size of the structure, since str_off and
 * hash_off need to point somewhere past the header.
 */
void
print_einfo(uint8_t flags, bblk_einfo_t *einfo, unsigned long bufsize)
{
        int             i = 0;
        char            *version;
        boolean_t       has_hash = B_FALSE;
        unsigned char   *hash = NULL;

        if (einfo->str_off + einfo->str_size > bufsize) {
                (void) fprintf(stdout, gettext("String offset %d is beyond the "
                    "buffer size\n"), einfo->str_off);
                return;
        }

        version = (char *)einfo + einfo->str_off;
        if (einfo->hash_type != BBLK_NO_HASH &&
            einfo->hash_type < BBLK_HASH_TOT) {
                if (einfo->hash_off + einfo->hash_size > bufsize) {
                        (void) fprintf(stdout, gettext("Warning: hashing "
                            "present but hash offset %d is beyond the buffer "
                            "size\n"), einfo->hash_off);
                        has_hash = B_FALSE;
                } else {
                        hash = (unsigned char *)einfo + einfo->hash_off;
                        has_hash = B_TRUE;
                }
        }

        if (flags & EINFO_PRINT_HEADER) {
                (void) fprintf(stdout, "Boot Block Extended Info Header:\n");
                (void) fprintf(stdout, "\tmagic: ");
                for (i = 0; i < EINFO_MAGIC_SIZE; i++)
                        (void) fprintf(stdout, "%c", einfo->magic[i]);
                (void) fprintf(stdout, "\n");
                (void) fprintf(stdout, "\tversion: %d\n", einfo->version);
                (void) fprintf(stdout, "\tflags: %x\n", einfo->flags);
                (void) fprintf(stdout, "\textended version string offset: %d\n",
                    einfo->str_off);
                (void) fprintf(stdout, "\textended version string size: %d\n",
                    einfo->str_size);
                (void) fprintf(stdout, "\thashing type: %d (%s)\n",
                    einfo->hash_type, has_hash ?
                    bblk_hash_list[einfo->hash_type]->name : "nil");
                (void) fprintf(stdout, "\thash offset: %d\n", einfo->hash_off);
                (void) fprintf(stdout, "\thash size: %d\n", einfo->hash_size);
        }

        if (flags & EINFO_EASY_PARSE) {
                (void) fprintf(stdout, "%s\n", version);
        } else {
                (void) fprintf(stdout, "Extended version string: %s\n",
                    version);
                if (has_hash) {
                        (void) fprintf(stdout, "%s hash: ",
                            bblk_hash_list[einfo->hash_type]->name);
                } else {
                        (void) fprintf(stdout, "No hashing available\n");
                }
        }

        if (has_hash) {
                for (i = 0; i < einfo->hash_size; i++) {
                        (void) fprintf(stdout, "%02x", hash[i]);
                }
                (void) fprintf(stdout, "\n");
        }
}

static int
compute_hash(bblk_hs_t *hs, unsigned char *dest, bblk_hash_t *hash)
{
        if (hs == NULL || dest == NULL || hash == NULL)
                return (-1);

        hash->compute_hash(dest, hs->src_buf, hs->src_size);
        return (0);
}

int
prepare_and_write_einfo(unsigned char *dest, char *infostr, bblk_hs_t *hs,
    uint32_t maxsize, uint32_t *used_space)
{
        uint16_t        hash_size;
        uint32_t        hash_off;
        unsigned char   *data;
        bblk_einfo_t    *einfo = (bblk_einfo_t *)dest;
        bblk_hash_t     *hashinfo = bblk_hash_list[BBLK_DEFAULT_HASH];

        /*
         * 'dest' might be both containing the buffer we want to hash and
         * containing our einfo structure: delay any update of it after the
         * hashing has been calculated.
         */
        hash_size = hashinfo->size;
        hash_off = sizeof (bblk_einfo_t);

        if (hash_off + hash_size > maxsize) {
                (void) fprintf(stderr, gettext("Unable to add extended info, "
                    "not enough space\n"));
                return (-1);
        }

        data = dest + hash_off;
        if (compute_hash(hs, data, hashinfo) < 0) {
                (void) fprintf(stderr, gettext("%s hash operation failed\n"),
                    hashinfo->name);
                einfo->hash_type = bblk_no_hash.type;
                einfo->hash_size = bblk_no_hash.size;
        } else {
                einfo->hash_type = hashinfo->type;
                einfo->hash_size = hashinfo->size;
        }

        (void) memcpy(einfo->magic, EINFO_MAGIC, EINFO_MAGIC_SIZE);
        einfo->version = BBLK_EINFO_VERSION;
        einfo->flags = 0;
        einfo->hash_off = hash_off;
        einfo->hash_size = hash_size;
        einfo->str_off = einfo->hash_off + einfo->hash_size + 1;

        if (infostr == NULL) {
                (void) fprintf(stderr, gettext("Unable to add extended info, "
                    "string is empty\n"));
                return (-1);
        }
        einfo->str_size = strlen(infostr);

        if (einfo->str_off + einfo->str_size > maxsize) {
                (void) fprintf(stderr, gettext("Unable to add extended info, "
                    "not enough space\n"));
                return (-1);
        }

        data = dest + einfo->str_off;
        (void) memcpy(data, infostr, einfo->str_size);
        *used_space = einfo->str_off + einfo->str_size;

        return (0);
}

/*
 * einfo_should_update()
 * Given information on the boot block currently on disk (disk_einfo) and
 * information on the supplied boot block (hs for hashing, verstr as the
 * associated version string) decide if an update of the on-disk boot block
 * is necessary or not.
 */
boolean_t
einfo_should_update(bblk_einfo_t *disk_einfo, bblk_hs_t *hs, char *verstr)
{
        bblk_hash_t     *hashing;
        unsigned char   *disk_hash;
        unsigned char   *local_hash;
        char            *disk_version;
        int             retval;

        if (disk_einfo == NULL)
                return (B_TRUE);

        if (memcmp(disk_einfo->magic, EINFO_MAGIC, EINFO_MAGIC_SIZE) != 0)
                return (B_TRUE);

        if (disk_einfo->version < BBLK_EINFO_VERSION)
                return (B_TRUE);

        disk_version = einfo_get_string(disk_einfo);
        retval = einfo_compare_version(verstr, disk_version);
        /*
         * If something goes wrong or if the on-disk version is more recent
         * do not update the bootblock.
         */
        if (retval == -1 || retval == 2)
                return (B_FALSE);

        /*
         * If we got here it means that the two version strings are either
         * equal or the new bootblk binary is more recent. In order to save
         * some needless writes let's use the hash to determine if an update
         * is really necessary.
         */
        if (disk_einfo->hash_type == bblk_no_hash.type)
                return (B_TRUE);

        if (disk_einfo->hash_type >= BBLK_HASH_TOT)
                return (B_TRUE);

        hashing = bblk_hash_list[disk_einfo->hash_type];

        local_hash = malloc(hashing->size);
        if (local_hash == NULL)
                return (B_TRUE);

        /*
         * Failure in computing the hash may mean something wrong
         * with the boot block file. Better be conservative here.
         */
        if (compute_hash(hs, local_hash, hashing) < 0) {
                free(local_hash);
                return (B_FALSE);
        }

        disk_hash = (unsigned char *)einfo_get_hash(disk_einfo);

        if (memcmp(local_hash, disk_hash, disk_einfo->hash_size) == 0) {
                free(local_hash);
                return (B_FALSE);
        }

        free(local_hash);
        return (B_TRUE);
}

char *
einfo_get_string(bblk_einfo_t *einfo)
{
        if (einfo == NULL)
                return (NULL);

        return ((char *)einfo + einfo->str_off);
}

char *
einfo_get_hash(bblk_einfo_t *einfo)
{
        if (einfo == NULL)
                return (NULL);

        return ((char *)einfo + einfo->hash_off);
}