/*
 * volume_id - reads filesystem label and uuid
 *
 * Copyright (C) 2005 Kay Sievers <kay.sievers@vrfy.org>
 *
 *      This library is free software; you can redistribute it and/or
 *      modify it under the terms of the GNU Lesser General Public
 *      License as published by the Free Software Foundation; either
 *      version 2.1 of the License, or (at your option) any later version.
 *
 *      This library is distributed in the hope that it will be useful,
 *      but WITHOUT ANY WARRANTY; without even the implied warranty of
 *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 *      Lesser General Public License for more details.
 *
 *      You should have received a copy of the GNU Lesser General Public
 *      License along with this library; if not, write to the Free Software
 *      Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

#include "volume_id_internal.h"

void volume_id_set_unicode16(char *str, size_t len, const uint8_t *buf, enum endian endianess, size_t count)
{
        unsigned i, j;
        unsigned c;

        j = 0;
        for (i = 0; i + 2 <= count; i += 2) {
                if (endianess == LE)
                        c = (buf[i+1] << 8) | buf[i];
                else
                        c = (buf[i] << 8) | buf[i+1];
                if (c == 0)
                        break;
                if (j+1 >= len)
                        break;
                if (c < 0x80) {
                        /* 0xxxxxxx */
                } else {
                        uint8_t topbits = 0xc0;
                        if (j+2 >= len)
                                break;
                        if (c < 0x800) {
                                /* 110yyyxx 10xxxxxx */
                        } else {
                                if (j+3 >= len)
                                        break;
                                /* 1110yyyy 10yyyyxx 10xxxxxx */
                                str[j++] = (uint8_t) (0xe0 | (c >> 12));
                                topbits = 0x80;
                        }
                        str[j++] = (uint8_t) (topbits | ((c >> 6) & 0x3f));
                        c = 0x80 | (c & 0x3f);
                }
                str[j++] = (uint8_t) c;
        }
        str[j] = '\0';
}

#ifdef UNUSED
static const char *usage_to_string(enum volume_id_usage usage_id)
{
        switch (usage_id) {
        case VOLUME_ID_FILESYSTEM:
                return "filesystem";
        case VOLUME_ID_PARTITIONTABLE:
                return "partitiontable";
        case VOLUME_ID_OTHER:
                return "other";
        case VOLUME_ID_RAID:
                return "raid";
        case VOLUME_ID_DISKLABEL:
                return "disklabel";
        case VOLUME_ID_CRYPTO:
                return "crypto";
        case VOLUME_ID_UNPROBED:
                return "unprobed";
        case VOLUME_ID_UNUSED:
                return "unused";
        }
        return NULL;
}

void volume_id_set_usage_part(struct volume_id_partition *part, enum volume_id_usage usage_id)
{
        part->usage_id = usage_id;
        part->usage = usage_to_string(usage_id);
}

void volume_id_set_usage(struct volume_id *id, enum volume_id_usage usage_id)
{
        id->usage_id = usage_id;
        id->usage = usage_to_string(usage_id);
}

void volume_id_set_label_raw(struct volume_id *id, const uint8_t *buf, size_t count)
{
        memcpy(id->label_raw, buf, count);
        id->label_raw_len = count;
}
#endif

#ifdef NOT_NEEDED
static size_t strnlen(const char *s, size_t maxlen)
{
        size_t i;
        if (!maxlen) return 0;
        if (!s) return 0;
        for (i = 0; *s && i < maxlen; ++s) ++i;
        return i;
}
#endif

void volume_id_set_label_string(struct volume_id *id, const uint8_t *buf, size_t count)
{
        unsigned i;

        memcpy(id->label, buf, count);

        /* remove trailing whitespace */
        i = strnlen(id->label, count);
        while (i--) {
                if (!isspace(id->label[i]))
                        break;
        }
        id->label[i+1] = '\0';
}

void volume_id_set_label_unicode16(struct volume_id *id, const uint8_t *buf, enum endian endianess, size_t count)
{
        volume_id_set_unicode16(id->label, sizeof(id->label), buf, endianess, count);
}

void volume_id_set_uuid(struct volume_id *id, const uint8_t *buf, enum uuid_format format)
{
        unsigned i;
        unsigned count = (format == UUID_DCE_STRING ? VOLUME_ID_UUID_SIZE : 4 << format);

//      memcpy(id->uuid_raw, buf, count);
//      id->uuid_raw_len = count;

        /* if set, create string in the same format, the native platform uses */
        for (i = 0; i < count; i++)
                if (buf[i] != 0)
                        goto set;
        return; /* all bytes are zero, leave it empty ("") */

set:
        switch (format) {
        case UUID_DOS:
                sprintf(id->uuid, "%02X%02X-%02X%02X",
                        buf[3], buf[2], buf[1], buf[0]);
                break;
        case UUID_NTFS:
                sprintf(id->uuid, "%02X%02X%02X%02X%02X%02X%02X%02X",
                        buf[7], buf[6], buf[5], buf[4],
                        buf[3], buf[2], buf[1], buf[0]);
                break;
        case UUID_DCE:
                sprintf(id->uuid,
                        "%02x%02x%02x%02x-%02x%02x-%02x%02x-%02x%02x-%02x%02x%02x%02x%02x%02x",
                        buf[0], buf[1], buf[2], buf[3],
                        buf[4], buf[5],
                        buf[6], buf[7],
                        buf[8], buf[9],
                        buf[10], buf[11], buf[12], buf[13], buf[14], buf[15]);
                break;
        case UUID_DCE_STRING:
                memcpy(id->uuid, buf, count);
                id->uuid[count] = '\0';
                break;
        }
}

/* Do not use xlseek here. With it, single corrupted filesystem
 * may result in attempt to seek past device -> exit.
 * It's better to ignore such fs and continue.  */
void *volume_id_get_buffer(struct volume_id *id, uint64_t off, size_t len)
{
        uint8_t *dst;
        unsigned small_off;
        ssize_t read_len;

        dbg("get buffer off 0x%llx(%llu), len 0x%zx",
                (unsigned long long) off, (unsigned long long) off, len);

        /* check if requested area fits in superblock buffer */
        if (off + len <= SB_BUFFER_SIZE
         /* && off <= SB_BUFFER_SIZE - want this paranoid overflow check? */
        ) {
                if (id->sbbuf == NULL) {
                        id->sbbuf = xmalloc(SB_BUFFER_SIZE);
                }
                small_off = off;
                dst = id->sbbuf;

                /* check if we need to read */
                len += off;
                if (len <= id->sbbuf_len)
                        goto ret; /* we already have it */

                dbg("read sbbuf len:0x%x", (unsigned) len);
                id->sbbuf_len = len;
                off = 0;
                goto do_read;
        }

        if (len > SEEK_BUFFER_SIZE) {
                dbg("seek buffer too small %d", SEEK_BUFFER_SIZE);
                return NULL;
        }
        dst = id->seekbuf;

        /* check if we need to read */
        if ((off >= id->seekbuf_off)
         && ((off + len) <= (id->seekbuf_off + id->seekbuf_len))
        ) {
                small_off = off - id->seekbuf_off; /* can't overflow */
                goto ret; /* we already have it */
        }

        id->seekbuf_off = off;
        id->seekbuf_len = len;
        id->seekbuf = xrealloc(id->seekbuf, len);
        small_off = 0;
        dst = id->seekbuf;
        dbg("read seekbuf off:0x%llx len:0x%zx",
                                (unsigned long long) off, len);
 do_read:
        if (lseek(id->fd, off, SEEK_SET) != off) {
                dbg("seek(0x%llx) failed", (unsigned long long) off);
                goto err;
        }
        read_len = full_read(id->fd, dst, len);
        if (read_len != len) {
                dbg("requested 0x%x bytes, got 0x%x bytes",
                                (unsigned) len, (unsigned) read_len);
 err:
                /* No filesystem can be this tiny. It's most likely
                 * non-associated loop device, empty drive and so on.
                 * Flag it, making it possible to short circuit future
                 * accesses. Rationale:
                 * users complained of slow blkid due to empty floppy drives.
                 */
                if (off < 64*1024)
                        id->error = 1;
                /* id->seekbuf_len or id->sbbuf_len is wrong now! Fixing. */
                volume_id_free_buffer(id);
                return NULL;
        }
 ret:
        return dst + small_off;
}

void volume_id_free_buffer(struct volume_id *id)
{
        free(id->sbbuf);
        id->sbbuf = NULL;
        id->sbbuf_len = 0;
        free(id->seekbuf);
        id->seekbuf = NULL;
        id->seekbuf_len = 0;
        id->seekbuf_off = 0; /* paranoia */
}