path: root/extras/volume_id/lib/volume_id.c

/*
 * volume_id - reads volume label and uuid
 *
 * Copyright (C) 2005-2007 Kay Sievers <kay.sievers@vrfy.org>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#ifndef _GNU_SOURCE
#define _GNU_SOURCE 1
#endif

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>
#include <ctype.h>
#include <fcntl.h>
#include <sys/stat.h>

#include "libvolume_id.h"
#include "libvolume_id-private.h"

#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))

struct prober {
	volume_id_probe_fn_t prober;
	const char *name[4];
};

static const struct prober prober_raid[] = {
	{ volume_id_probe_linux_raid, { "linux_raid", } },
	{ volume_id_probe_ddf_raid, { "ddf_raid", } },
	{ volume_id_probe_intel_software_raid, { "isw_raid", } },
	{ volume_id_probe_lsi_mega_raid, { "lsi_mega_raid", } },
	{ volume_id_probe_via_raid, { "via_raid", } },
	{ volume_id_probe_silicon_medley_raid, { "silicon_medley_raid", } },
	{ volume_id_probe_nvidia_raid, { "nvidia_raid", } },
	{ volume_id_probe_promise_fasttrack_raid, { "promise_fasttrack_raid", } },
	{ volume_id_probe_highpoint_45x_raid, { "highpoint_raid", } },
	{ volume_id_probe_adaptec_raid, { "adaptec_raid", } },
	{ volume_id_probe_jmicron_raid, { "jmicron_raid", } },
	{ volume_id_probe_lvm1, { "lvm1", } },
	{ volume_id_probe_lvm2, { "lvm2", } },
	{ volume_id_probe_highpoint_37x_raid, { "highpoint_raid", } },
};

static const struct prober prober_filesystem[] = {
	{ volume_id_probe_vfat, { "vfat", } },
	{ volume_id_probe_linux_swap, { "swap", } },
	{ volume_id_probe_luks, { "luks", } },
	{ volume_id_probe_xfs, { "xfs", } },
	{ volume_id_probe_ext, { "ext2", "ext3", "jbd", } },
	{ volume_id_probe_reiserfs, { "reiserfs", "reiser4", } },
	{ volume_id_probe_jfs, { "jfs", } },
	{ volume_id_probe_udf, { "udf", } },
	{ volume_id_probe_iso9660, { "iso9660", } },
	{ volume_id_probe_hfs_hfsplus, { "hfs", "hfsplus", } },
	{ volume_id_probe_ufs, { "ufs", } },
	{ volume_id_probe_ntfs, { "ntfs", } },
	{ volume_id_probe_cramfs, { "cramfs", } },
	{ volume_id_probe_romfs, { "romfs", } },
	{ volume_id_probe_hpfs, { "hpfs", } },
	{ volume_id_probe_sysv, { "sysv", "xenix", } },
	{ volume_id_probe_minix, { "minix",  } },
	{ volume_id_probe_gfs, { "gfs", } },
	{ volume_id_probe_gfs2, { "gfs2", } },
	{ volume_id_probe_ocfs1, { "ocfs1", } },
	{ volume_id_probe_ocfs2, { "ocfs2", } },
	{ volume_id_probe_vxfs, { "vxfs", } },
	{ volume_id_probe_squashfs, { "squashfs", } },
	{ volume_id_probe_netware, { "netware", } },
	{ volume_id_probe_oracleasm, { "oracleasm", } },
	{ volume_id_probe_btrfs, { "btrfs", } },
};

/* the user can overwrite this log function */
static void default_log(int priority, const char *file, int line, const char *format, ...)
{
	return;
}

volume_id_log_fn_t volume_id_log_fn = default_log;

/**
 * volume_id_get_prober_by_type:
 * @type: Type string.
 *
 * Lookup the probing function for a specific type.
 *
 * Returns: The probing function for the given type, #NULL otherwise.
 **/
const volume_id_probe_fn_t *volume_id_get_prober_by_type(const char *type)
{
	unsigned int p, n;

	if (type == NULL)
		return NULL;

	for (p = 0; p < ARRAY_SIZE(prober_raid); p++)
		for (n = 0; prober_raid[p].name[n] !=  NULL; n++)
			if (strcmp(type, prober_raid[p].name[n]) == 0)
				return &prober_raid[p].prober;
	for (p = 0; p < ARRAY_SIZE(prober_filesystem); p++)
		for (n = 0; prober_filesystem[p].name[n] !=  NULL; n++)
			if (strcmp(type, prober_filesystem[p].name[n]) == 0)
				return &prober_filesystem[p].prober;
	return NULL;
}

/**
 * volume_id_get_label:
 * @id: Probing context.
 * @label: Label string. Must not be freed by the caller.
 *
 * Get the label string after a successful probe. Unicode
 * is translated to UTF-8.
 *
 * Returns: 1 if the value was set, 0 otherwise.
 **/
int volume_id_get_label(struct volume_id *id, const char **label)
{
	if (id == NULL)
		return 0;
	if (label == NULL)
		return 0;
	if (id->usage_id == VOLUME_ID_UNUSED)
		return 0;

	*label = id->label;
	return 1;
}

/**
 * volume_id_get_label_raw:
 * @id: Probing context.
 * @label: Label byte array. Must not be freed by the caller.
 * @len: Length of raw label byte array.
 *
 * Get the raw label byte array after a successful probe. It may
 * contain undecoded multibyte character streams.
 *
 * Returns: 1 if the value was set, 0 otherwise.
 **/
int volume_id_get_label_raw(struct volume_id *id, const uint8_t **label, size_t *len)
{
	if (id == NULL)
		return 0;
	if (label == NULL)
		return 0;
	if (len == NULL)
		return 0;
	if (id->usage_id == VOLUME_ID_UNUSED)
		return 0;

	*label = id->label_raw;
	*len = id->label_raw_len;
	return 1;
}

/**
 * volume_id_get_uuid:
 * @id: Probing context.
 * @uuid: UUID string. Must not be freed by the caller.
 *
 * Get the raw UUID string after a successful probe.
 *
 * Returns: 1 if the value was set, 0 otherwise.
 **/
int volume_id_get_uuid(struct volume_id *id, const char **uuid)
{
	if (id == NULL)
		return 0;
	if (uuid == NULL)
		return 0;
	if (id->usage_id == VOLUME_ID_UNUSED)
		return 0;

	*uuid = id->uuid;
	return 1;
}

/**
 * volume_id_get_uuid_raw:
 * @id: Probing context.
 * @uuid: UUID byte array. Must not be freed by the caller.
 * @len: Length of raw UUID byte array.
 *
 * Get the raw UUID byte array after a successful probe. It may
 * contain unconverted endianes values.
 *
 * Returns: 1 if the value was set, 0 otherwise.
 **/
int volume_id_get_uuid_raw(struct volume_id *id, const uint8_t **uuid, size_t *len)
{
	if (id == NULL)
		return 0;
	if (uuid == NULL)
		return 0;
	if (len == NULL)
		return 0;
	if (id->usage_id == VOLUME_ID_UNUSED)
		return 0;

	*uuid = id->uuid_raw;
	*len = id->uuid_raw_len;
	return 1;
}

/**
 * volume_id_get_usage:
 * @id: Probing context.
 * @usage: Usage string. Must not be freed by the caller.
 *
 * Get the usage string after a successful probe.
 *
 * Returns: 1 if the value was set, 0 otherwise.
 **/
int volume_id_get_usage(struct volume_id *id, const char **usage)
{
	if (id == NULL)
		return 0;
	if (usage == NULL)
		return 0;
	if (id->usage_id == VOLUME_ID_UNUSED)
		return 0;

	*usage = id->usage;
	return 1;
}

/**
 * volume_id_get_type:
 * @id: Probing context
 * @type: Type string. Must not be freed by the caller.
 *
 * Get the type string after a successful probe.
 *
 * Returns: 1 if the value was set, 0 otherwise.
 **/
int volume_id_get_type(struct volume_id *id, const char **type)
{
	if (id == NULL)
		return 0;
	if (type == NULL)
		return 0;
	if (id->usage_id == VOLUME_ID_UNUSED)
		return 0;

	*type = id->type;
	return 1;
}

/**
 * volume_id_get_type_version:
 * @id: Probing context.
 * @type_version: Type version string. Must not be freed by the caller.
 *
 * Get the Type version string after a successful probe.
 *
 * Returns: 1 if the value was set, 0 otherwise.
 **/
int volume_id_get_type_version(struct volume_id *id, const char **type_version)
{
	if (id == NULL)
		return 0;
	if (type_version == NULL)
		return 0;
	if (id->usage_id == VOLUME_ID_UNUSED)
		return 0;

	*type_version = id->type_version;
	return 1;
}

static int needs_encoding(const char c)
{
	if ((c >= '0' && c <= '9') ||
	    (c >= 'A' && c <= 'Z') ||
	    (c >= 'a' && c <= 'z') ||
	    strchr(ALLOWED_CHARS, c))
		return 0;
	return 1;
}

/**
 * volume_id_encode_string:
 * @str: Input string to be encoded.
 * @str_enc: Target string to store the encoded input.
 * @len: Location to store the encoded string. The target string,
 * which may be four times as long as the input string.
 *
 * Encode all potentially unsafe characters of a string to the
 * corresponding hex value prefixed by '\x'.
 *
 * Returns: 1 if the entire string was copied, 0 otherwise.
 **/
int volume_id_encode_string(const char *str, char *str_enc, size_t len)
{
	size_t i, j;

	if (str == NULL || str_enc == NULL || len == 0)
		return 0;

	str_enc[0] = '\0';
	for (i = 0, j = 0; str[i] != '\0'; i++) {
		int seqlen;

		seqlen = volume_id_utf8_encoded_valid_unichar(&str[i]);
		if (seqlen > 1) {
			memcpy(&str_enc[j], &str[i], seqlen);
			j += seqlen;
			i += (seqlen-1);
		} else if (str[i] == '\\' || needs_encoding(str[i])) {
			sprintf(&str_enc[j], "\\x%02x", (unsigned char) str[i]);
			j += 4;
		} else {
			str_enc[j] = str[i];
			j++;
		}
		if (j+3 >= len)
			goto err;
	}
	str_enc[j] = '\0';
	return 1;
err:
	return 0;
}

/* run only once into a timeout for unreadable devices */
static int device_is_readable(struct volume_id *id, uint64_t off)
{
	if (volume_id_get_buffer(id, off, 0x200) != NULL)
		return 1;
	return 0;
}

/**
 * volume_id_probe_raid:
 * @id: Probing context.
 * @off: Probing offset relative to the start of the device.
 * @size: Total size of the device.
 *
 * Probe device for all known raid signatures.
 *
 * Returns: 0 on successful probe, otherwise negative value.
 **/
int volume_id_probe_raid(struct volume_id *id, uint64_t off, uint64_t size)
{
	unsigned int i;

	if (id == NULL)
		return -EINVAL;

	if (!device_is_readable(id, off))
		return -1;

	info("probing at offset 0x%" PRIx64 ", size 0x%" PRIx64 "\n", off, size);

	for (i = 0; i < ARRAY_SIZE(prober_raid); i++) {
		if (prober_raid[i].prober(id, off, size) == 0) {
			info("signature '%s' detected\n", id->type);
			goto found;
		}
	}
	return -1;

found:
	/* If recognized, we free the allocated buffers */
	volume_id_free_buffer(id);
	return 0;
}

static void volume_id_reset_result(struct volume_id *id)
{
	id->label_raw_len = 0;
	id->label[0] = '\0';
	id->uuid_raw_len = 0;
	id->uuid[0] = '\0';
	id->usage_id = VOLUME_ID_UNUSED;
	id->usage = NULL;
	id->type = NULL;
	id->type_version[0] = '\0';
}

/**
 * volume_id_probe_filesystem:
 * @id: Probing context.
 * @off: Probing offset relative to the start of the device.
 * @size: Total size of the device.
 *
 * Probe device for all known filesystem signatures.
 *
 * Returns: 0 on successful probe, otherwise negative value.
 **/
int volume_id_probe_filesystem(struct volume_id *id, uint64_t off, uint64_t size)
{
	unsigned int i;

	if (id == NULL)
		return -EINVAL;

	if (!device_is_readable(id, off))
		return -1;

	info("probing at offset 0x%" PRIx64 ", size 0x%" PRIx64 "\n", off, size);

	/*
	 * We probe for all known filesystems to find conflicting signatures. If
	 * we find multiple matching signatures and one of the detected filesystem
	 * types claims that it can not co-exist with any other filesystem type,
	 * we do not return a probing result.
	 *
	 * We can not afford to mount a volume with the wrong filesystem code and
	 * possibly corrupt it. Linux sytems have the problem of dozens of possible
	 * filesystem types, and volumes with left-over signatures from former
	 * filesystem types. Invalid signatures need to be removed from the volume
	 * to make the filesystem detection successful.
	 *
	 * We do not want to read that many bytes from probed floppies, skip volumes
	 * smaller than a usual floppy disk.
	 */
	if (size > 1440 * 1024) {
		int found = 0;
		int force_unique_result = 0;
		int first_match = -1;

		volume_id_reset_result(id);
		for (i = 0; i < ARRAY_SIZE(prober_filesystem); i++) {
			int match;

			match = (prober_filesystem[i].prober(id, off, size) == 0);
			if (match) {
				info("signature '%s' %i detected\n", id->type, i);
				if (id->force_unique_result)
					force_unique_result = 1;
				if (found && force_unique_result) {
					info("conflicting signatures found, skip results\n");
					return -1;
				}
				found++;
				if (first_match < 0)
					first_match = i;
			}
		}
		if (found < 1)
			return -1;
		if (found == 1)
			goto found;
		if (found > 1) {
			volume_id_reset_result(id);
			info("re-read first match metadata %i\n", first_match);
			if (prober_filesystem[first_match].prober(id, off, size) == 0)
				goto found;
			return -1;
		}
	}

	/* return the first match */
	volume_id_reset_result(id);
	for (i = 0; i < ARRAY_SIZE(prober_filesystem); i++) {
		if (prober_filesystem[i].prober(id, off, size) == 0) {
			info("signature '%s' detected\n", id->type);
			goto found;
		}
	}
	return -1;
found:
	/* If recognized, we free the allocated buffers */
	volume_id_free_buffer(id);
	return 0;
}

/**
 * volume_id_probe_all:
 * @id: Probing context.
 * @off: Probing offset relative to the start of the device.
 * @size: Total size of the device.
 *
 * Probe device for all known raid and filesystem signatures.
 *
 * Returns: 0 on successful probe, otherwise negative value.
 **/
int volume_id_probe_all(struct volume_id *id, uint64_t off, uint64_t size)
{
	if (id == NULL)
		return -EINVAL;

	if (!device_is_readable(id, off))
		return -1;

	/* probe for raid first, because fs probes may be successful on raid members */
	if (volume_id_probe_raid(id, off, size) == 0)
		return 0;

	if (volume_id_probe_filesystem(id, off, size) == 0)
		return 0;

	return -1;
}

/**
 * volume_id_probe_raid:
 * @all_probers_fn: prober function to called for all known probing routines.
 * @id: Context passed to prober function.
 * @off: Offset value passed to prober function.
 * @size: Size value passed to prober function.
 * @data: Arbitrary data passed to the prober function.
 *
 * Run a custom function for all known probing routines.
 **/
void volume_id_all_probers(all_probers_fn_t all_probers_fn,
			   struct volume_id *id, uint64_t off, uint64_t size,
			   void *data)
{
	unsigned int i;

	if (all_probers_fn == NULL)
		return;

	for (i = 0; i < ARRAY_SIZE(prober_raid); i++)
		if (all_probers_fn(prober_raid[i].prober, id, off, size, data) != 0)
			goto out;
	for (i = 0; i < ARRAY_SIZE(prober_filesystem); i++)
		if (all_probers_fn(prober_filesystem[i].prober, id, off, size, data) != 0)
			goto out;
out:
	return;
}

/**
 * volume_id_open_fd:
 * @id: Probing context.
 * @fd: Open file descriptor of device to read from.
 *
 * Create the context for probing.
 *
 * Returns: Probing context, or #NULL on failure.
 **/
struct volume_id *volume_id_open_fd(int fd)
{
	struct volume_id *id;

	id = calloc(1, sizeof(struct volume_id));
	if (id == NULL)
		return NULL;

	id->fd = fd;

	return id;
}

/**
 * volume_id_close:
 * @id: Probing context.
 *
 * Release probing context and free all associated data.
 */
void volume_id_close(struct volume_id *id)
{
	if (id == NULL)
		return;

	volume_id_free_buffer(id);

	free(id);
}