libdm-iface.c

Linux Device Mapper Source Code

/*
 * Copyright (C) 2001-2004 Sistina Software, Inc. All rights reserved.
 * Copyright (C) 2004-2007 Red Hat, Inc. All rights reserved.
 *
 * This file is part of the device-mapper userspace tools.
 *
 * This copyrighted material is made available to anyone wishing to use,
 * modify, copy, or redistribute it subject to the terms and conditions
 * of the GNU Lesser General Public License v.2.1.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#include "lib.h"
#include "libdm-targets.h"
#include "libdm-common.h"

#ifdef DM_COMPAT
#  include "libdm-compat.h"
#endif

#include <fcntl.h>
#include <dirent.h>
#include <sys/ioctl.h>
#include <limits.h>

#ifdef linux
#  include "kdev_t.h"
#  include <linux/limits.h>
#else
#  define MAJOR(x) major((x))
#  define MINOR(x) minor((x))
#  define MKDEV(x,y) makedev((x),(y))
#endif

#include <linux/dm-ioctl.h>

/*
 * Ensure build compatibility.  
 * The hard-coded versions here are the highest present 
 * in the _cmd_data arrays.
 */

#if !((DM_VERSION_MAJOR == 1 && DM_VERSION_MINOR >= 0) || \
      (DM_VERSION_MAJOR == 4 && DM_VERSION_MINOR >= 0))
#error The version of dm-ioctl.h included is incompatible.
#endif

/* FIXME This should be exported in device-mapper.h */
#define DM_NAME "device-mapper"

#define PROC_MISC "/proc/misc"
#define PROC_DEVICES "/proc/devices"
#define MISC_NAME "misc"

#define NUMBER_OF_MAJORS 4096

/* dm major version no for running kernel */
static unsigned _dm_version = DM_VERSION_MAJOR;
static unsigned _dm_version_minor = 0;
static unsigned _dm_version_patchlevel = 0;
static int _log_suppress = 0;

static dm_bitset_t _dm_bitset = NULL;
static int _control_fd = -1;
static int _version_checked = 0;
static int _version_ok = 1;
static unsigned _ioctl_buffer_double_factor = 0;

/*
 * Support both old and new major numbers to ease the transition.
 * Clumsy, but only temporary.
 */
#if DM_VERSION_MAJOR == 4 && defined(DM_COMPAT)
const int _dm_compat = 1;
#else
const int _dm_compat = 0;
#endif


/* *INDENT-OFF* */
static struct cmd_data _cmd_data_v4[] = {
	{"create",	DM_DEV_CREATE,		{4, 0, 0}},
	{"reload",	DM_TABLE_LOAD,		{4, 0, 0}},
	{"remove",	DM_DEV_REMOVE,		{4, 0, 0}},
	{"remove_all",	DM_REMOVE_ALL,		{4, 0, 0}},
	{"suspend",	DM_DEV_SUSPEND,		{4, 0, 0}},
	{"resume",	DM_DEV_SUSPEND,		{4, 0, 0}},
	{"info",	DM_DEV_STATUS,		{4, 0, 0}},
	{"deps",	DM_TABLE_DEPS,		{4, 0, 0}},
	{"rename",	DM_DEV_RENAME,		{4, 0, 0}},
	{"version",	DM_VERSION,		{4, 0, 0}},
	{"status",	DM_TABLE_STATUS,	{4, 0, 0}},
	{"table",	DM_TABLE_STATUS,	{4, 0, 0}},
	{"waitevent",	DM_DEV_WAIT,		{4, 0, 0}},
	{"names",	DM_LIST_DEVICES,	{4, 0, 0}},
	{"clear",	DM_TABLE_CLEAR,		{4, 0, 0}},
	{"mknodes",	DM_DEV_STATUS,		{4, 0, 0}},
#ifdef DM_LIST_VERSIONS
	{"versions",	DM_LIST_VERSIONS,	{4, 1, 0}},
#endif
#ifdef DM_TARGET_MSG
	{"message",	DM_TARGET_MSG,		{4, 2, 0}},
#endif
#ifdef DM_DEV_SET_GEOMETRY
	{"setgeometry",	DM_DEV_SET_GEOMETRY,	{4, 6, 0}},
#endif
};
/* *INDENT-ON* */

#define ALIGNMENT_V1 sizeof(int)
#define ALIGNMENT 8

/* FIXME Rejig library to record & use errno instead */
#ifndef DM_EXISTS_FLAG
#  define DM_EXISTS_FLAG 0x00000004
#endif

static void *_align(void *ptr, unsigned int a)
{
	register unsigned long agn = --a;

	return (void *) (((unsigned long) ptr + agn) & ~agn);
}

#ifdef DM_IOCTLS
/*
 * Set number to NULL to populate _dm_bitset - otherwise first
 * match is returned.
 */
static int _get_proc_number(const char *file, const char *name,
			    uint32_t *number)
{
	FILE *fl;
	char nm[256];
	int c;
	uint32_t num;

	if (!(fl = fopen(file, "r"))) {
		log_sys_error("fopen", file);
		return 0;
	}

	while (!feof(fl)) {
		if (fscanf(fl, "%d %255s\n", &num, &nm[0]) == 2) {
			if (!strcmp(name, nm)) {
				if (number) {
					*number = num;
					if (fclose(fl))
						log_sys_error("fclose", file);
					return 1;
				}
				dm_bit_set(_dm_bitset, num);
			}
		} else do {
			c = fgetc(fl);
		} while (c != EOF && c != '\n');
	}
	if (fclose(fl))
		log_sys_error("fclose", file);

	if (number) {
		log_error("%s: No entry for %s found", file, name);
		return 0;
	}

	return 1;
}

static int _control_device_number(uint32_t *major, uint32_t *minor)
{
	if (!_get_proc_number(PROC_DEVICES, MISC_NAME, major) ||
	    !_get_proc_number(PROC_MISC, DM_NAME, minor)) {
		*major = 0;
		return 0;
	}

	return 1;
}

/*
 * Returns 1 if exists; 0 if it doesn't; -1 if it's wrong
 */
static int _control_exists(const char *control, uint32_t major, uint32_t minor)
{
	struct stat buf;

	if (stat(control, &buf) < 0) {
		if (errno != ENOENT)
			log_sys_error("stat", control);
		return 0;
	}

	if (!S_ISCHR(buf.st_mode)) {
		log_verbose("%s: Wrong inode type", control);
		if (!unlink(control))
			return 0;
		log_sys_error("unlink", control);
		return -1;
	}

	if (major && buf.st_rdev != MKDEV(major, minor)) {
		log_verbose("%s: Wrong device number: (%u, %u) instead of "
			    "(%u, %u)", control,
			    MAJOR(buf.st_mode), MINOR(buf.st_mode),
			    major, minor);
		if (!unlink(control))
			return 0;
		log_sys_error("unlink", control);
		return -1;
	}

	return 1;
}

static int _create_control(const char *control, uint32_t major, uint32_t minor)
{
	int ret;
	mode_t old_umask;

	if (!major)
		return 0;

	old_umask = umask(0022);
	ret = dm_create_dir(dm_dir());
	umask(old_umask);

	if (!ret)
		return 0;

	log_verbose("Creating device %s (%u, %u)", control, major, minor);

	if (mknod(control, S_IFCHR | S_IRUSR | S_IWUSR,
		  MKDEV(major, minor)) < 0)  {
		log_sys_error("mknod", control);
		return 0;
	}

#ifdef HAVE_SELINUX
	if (!dm_set_selinux_context(control, S_IFCHR)) {
		stack;
		return 0;
	}
#endif

	return 1;
}
#endif

static int _create_dm_bitset(void)
{
#ifdef DM_IOCTLS
	if (_dm_bitset)
		return 1;

	if (!(_dm_bitset = dm_bitset_create(NULL, NUMBER_OF_MAJORS)))
		return 0;

	if (!_get_proc_number(PROC_DEVICES, DM_NAME, NULL)) {
		dm_bitset_destroy(_dm_bitset);
		_dm_bitset = NULL;
		return 0;
	}

	return 1;
#else
	return 0;
#endif
}

int dm_is_dm_major(uint32_t major)
{
	if (!_create_dm_bitset())
		return 0;

	return dm_bit(_dm_bitset, major) ? 1 : 0;
}

static int _open_control(void)
{
#ifdef DM_IOCTLS
	char control[PATH_MAX];
	uint32_t major = 0, minor;

	if (_control_fd != -1)
		return 1;

	snprintf(control, sizeof(control), "%s/control", dm_dir());

	if (!_control_device_number(&major, &minor))
		log_error("Is device-mapper driver missing from kernel?");

	if (!_control_exists(control, major, minor) &&
	    !_create_control(control, major, minor))
		goto error;

	if ((_control_fd = open(control, O_RDWR)) < 0) {
		log_sys_error("open", control);
		goto error;
	}

	if (!_create_dm_bitset()) {
		log_error("Failed to set up list of device-mapper major numbers");
		return 0;
	}

	return 1;

error:
	log_error("Failure to communicate with kernel device-mapper driver.");
	return 0;
#else
	return 1;
#endif
}

void dm_task_destroy(struct dm_task *dmt)
{
	struct target *t, *n;

	for (t = dmt->head; t; t = n) {
		n = t->next;
		dm_free(t->params);
		dm_free(t->type);
		dm_free(t);
	}

	if (dmt->dev_name)
		dm_free(dmt->dev_name);

	if (dmt->newname)
		dm_free(dmt->newname);

	if (dmt->message)
		dm_free(dmt->message);

	if (dmt->dmi.v4)
		dm_free(dmt->dmi.v4);

	if (dmt->uuid)
		dm_free(dmt->uuid);

	dm_free(dmt);
}

/*
 * Protocol Version 1 compatibility functions.
 */

#ifdef DM_COMPAT

static int _dm_task_get_driver_version_v1(struct dm_task *dmt, char *version,
					  size_t size)
{
	unsigned int *v;

	if (!dmt->dmi.v1) {
		version[0] = '\0';
		return 0;
	}

	v = dmt->dmi.v1->version;
	snprintf(version, size, "%u.%u.%u", v[0], v[1], v[2]);
	return 1;
}

/* Unmarshall the target info returned from a status call */
static int _unmarshal_status_v1(struct dm_task *dmt, struct dm_ioctl_v1 *dmi)
{
	char *outbuf = (char *) dmi + dmi->data_start;
	char *outptr = outbuf;
	int32_t i;
	struct dm_target_spec_v1 *spec;

	for (i = 0; i < dmi->target_count; i++) {
		spec = (struct dm_target_spec_v1 *) outptr;

		if (!dm_task_add_target(dmt, spec->sector_start,
					(uint64_t) spec->length,
					spec->target_type,
					outptr + sizeof(*spec))) {
			return 0;
		}

		outptr = outbuf + spec->next;
	}

	return 1;
}

static int _dm_format_dev_v1(char *buf, int bufsize, uint32_t dev_major,
			     uint32_t dev_minor)
{
	int r;

	if (bufsize < 8)
		return 0;

	r = snprintf(buf, bufsize, "%03x:%03x", dev_major, dev_minor);
	if (r < 0 || r > bufsize - 1)
		return 0;

	return 1;
}

static int _dm_task_get_info_v1(struct dm_task *dmt, struct dm_info *info)
{
	if (!dmt->dmi.v1)
		return 0;

	memset(info, 0, sizeof(*info));

	info->exists = dmt->dmi.v1->flags & DM_EXISTS_FLAG ? 1 : 0;
	if (!info->exists)
		return 1;

	info->suspended = dmt->dmi.v1->flags & DM_SUSPEND_FLAG ? 1 : 0;
	info->read_only = dmt->dmi.v1->flags & DM_READONLY_FLAG ? 1 : 0;
	info->target_count = dmt->dmi.v1->target_count;
	info->open_count = dmt->dmi.v1->open_count;
	info->event_nr = 0;
	info->major = MAJOR(dmt->dmi.v1->dev);
	info->minor = MINOR(dmt->dmi.v1->dev);
	info->live_table = 1;
	info->inactive_table = 0;

	return 1;
}

static const char *_dm_task_get_name_v1(const struct dm_task *dmt)
{
	return (dmt->dmi.v1->name);
}

static const char *_dm_task_get_uuid_v1(const struct dm_task *dmt)
{
	return (dmt->dmi.v1->uuid);
}

static struct dm_deps *_dm_task_get_deps_v1(struct dm_task *dmt)
{
	log_error("deps version 1 no longer supported by libdevmapper");
	return NULL;
}

static struct dm_names *_dm_task_get_names_v1(struct dm_task *dmt)
{
	return (struct dm_names *) (((void *) dmt->dmi.v1) +
				    dmt->dmi.v1->data_start);
}

static void *_add_target_v1(struct target *t, void *out, void *end)
{
	void *out_sp = out;
	struct dm_target_spec_v1 sp;
	size_t sp_size = sizeof(struct dm_target_spec_v1);
	int len;
	const char no_space[] = "Ran out of memory building ioctl parameter";

	out += sp_size;
	if (out >= end) {
		log_error(no_space);
		return NULL;
	}

	sp.status = 0;
	sp.sector_start = t->start;
	sp.length = t->length;
	strncpy(sp.target_type, t->type, sizeof(sp.target_type));

	len = strlen(t->params);

	if ((out + len + 1) >= end) {
		log_error(no_space);

		log_error("t->params= '%s'", t->params);
		return NULL;
	}
	strcpy((char *) out, t->params);
	out += len + 1;

	/* align next block */
	out = _align(out, ALIGNMENT_V1);

	sp.next = out - out_sp;

	memcpy(out_sp, &sp, sp_size);

	return out;
}

static struct dm_ioctl_v1 *_flatten_v1(struct dm_task *dmt)
{
	const size_t min_size = 16 * 1024;
	const int (*version)[3];

	struct dm_ioctl_v1 *dmi;
	struct target *t;
	size_t len = sizeof(struct dm_ioctl_v1);
	void *b, *e;
	int count = 0;

	for (t = dmt->head; t; t = t->next) {
		len += sizeof(struct dm_target_spec_v1);
		len += strlen(t->params) + 1 + ALIGNMENT_V1;
		count++;
	}

	if (count && dmt->newname) {
		log_error("targets and newname are incompatible");
		return NULL;
	}

	if (dmt->newname)
		len += strlen(dmt->newname) + 1;

	/*
	 * Give len a minimum size so that we have space to store
	 * dependencies or status information.
	 */
	if (len < min_size)
		len = min_size;

	if (!(dmi = dm_malloc(len)))
		return NULL;

	memset(dmi, 0, len);

	version = &_cmd_data_v1[dmt->type].version;

	dmi->version[0] = (*version)[0];
	dmi->version[1] = (*version)[1];
	dmi->version[2] = (*version)[2];

	dmi->data_size = len;
	dmi->data_start = sizeof(struct dm_ioctl_v1);

	if (dmt->dev_name)
		strncpy(dmi->name, dmt->dev_name, sizeof(dmi->name));

	if (dmt->type == DM_DEVICE_SUSPEND)
		dmi->flags |= DM_SUSPEND_FLAG;
	if (dmt->read_only)
		dmi->flags |= DM_READONLY_FLAG;

	if (dmt->minor >= 0) {
		if (dmt->major <= 0) {
			log_error("Missing major number for persistent device");
			return NULL;
		}
		dmi->flags |= DM_PERSISTENT_DEV_FLAG;
		dmi->dev = MKDEV(dmt->major, dmt->minor);
	}

	if (dmt->uuid)
		strncpy(dmi->uuid, dmt->uuid, sizeof(dmi->uuid));

	dmi->target_count = count;

	b = (void *) (dmi + 1);
	e = (void *) ((char *) dmi + len);

	for (t = dmt->head; t; t = t->next)
		if (!(b = _add_target_v1(t, b, e)))
			goto bad;

	if (dmt->newname)
		strcpy(b, dmt->newname);

	return dmi;