text: /*
   * 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 */
  }
  