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platform_system_core/vold/devmapper.c

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/*
* Copyright (C) 2008 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <dirent.h>
#include <unistd.h>
#include <sched.h>
#include <fcntl.h>
#include <sys/mount.h>
#include <linux/loop.h>
#include <linux/dm-ioctl.h>
#include <cutils/config_utils.h>
#include <cutils/properties.h>
#include "vold.h"
#include "devmapper.h"
#define DEBUG_DEVMAPPER 1
static void *_align(void *ptr, unsigned int a)
{
register unsigned long agn = --a;
return (void *) (((unsigned long) ptr + agn) & ~agn);
}
static struct dm_ioctl *_dm_ioctl_setup(struct devmapping *dm, int flags)
{
void *buffer;
void *p;
const size_t min_size = 16 * 1024;
size_t len = sizeof(struct dm_ioctl);
struct dm_ioctl *io;
struct dm_target_spec *tgt;
int i;
char params[1024];
char key[80];
key[0] = '\0';
for (i = 0; i < (int) sizeof(dm->key); i++) {
char tmp[8];
sprintf(tmp, "%02x", dm->key[i]);
strcat(key, tmp);
}
char srcdev[128];
// XXX: Handle non crypt targets and non twofish (use param)
if (dm->src_type == dmsrc_loopback)
strcpy(srcdev, dm->type_data.loop.loop_dev);
else if (dm->src_type == dmsrc_partition)
strcpy(srcdev, dm->type_data.part.part_dev);
sprintf(params, "twofish %s 0 %s 0", key, srcdev);
LOG_VOL("Params = '%s'", params);
if (len < min_size)
len = min_size;
if (!(buffer = malloc(len))) {
LOGE("out of memory");
return NULL;
}
memset(buffer, 0, len);
io = buffer;
tgt = (struct dm_target_spec *) &buffer[sizeof(struct dm_ioctl)];
io->version[0] = 4;
io->version[1] = 0;
io->version[2] = 0;
io->data_size = len;
io->data_start = sizeof(struct dm_ioctl);
io->flags = flags;
io->dev = 0;
io->target_count = 1;
io->event_nr = 1;
strncpy(io->name, dm->target, sizeof(io->name));
tgt->status = 0;
tgt->sector_start = 0;
tgt->length = (dm->size_mb * (1024 * 1024)) / 512;
strncpy(tgt->target_type, "crypt", sizeof(tgt->target_type));
p = buffer + sizeof(struct dm_ioctl) + sizeof(struct dm_target_spec);
strcpy((char *) p, params);
p+= strlen(params) + 1;
p = _align(p, 8);
tgt->next = p - buffer;
return io;
}
static int get_next_available_dm()
{
int i;
for (i = 0; i < 8; i++) {
char path[255];
sprintf(path, "/dev/block/dm-%d", i);
if ((access(path, F_OK) < 0) && (errno == ENOENT))
return i;
}
LOGE("Out of device mapper numbers");
return -1;
}
static int create_devmapping(struct devmapping *dm)
{
struct dm_ioctl *io;
int rc, fd;
#if DEBUG_DEVMAPPER
LOG_VOL("create_devmapping():");
#endif
if (dm->dm_no < 0) {
LOGE("Invalid dm_no set");
return -EINVAL;
}
if ((fd = open("/dev/device-mapper", O_RDWR)) < 0) {
LOGE("Error opening device mapper (%d)", errno);
return -errno;
}
if (!(io = _dm_ioctl_setup(dm, 0))) {
LOGE("Unable to setup ioctl (out of memory)");
close(fd);
return -ENOMEM;
}
if ((rc = ioctl(fd, DM_DEV_CREATE, io)) < 0) {
LOGE("device-mapper create ioctl failed (%d)", errno);
rc = -errno;
goto out_free;
}
free(io);
if (!(io = _dm_ioctl_setup(dm, DM_STATUS_TABLE_FLAG))) {
LOGE("Unable to setup ioctl (out of memory)");
rc = -ENOMEM;
goto out_nofree;
}
if ((rc = ioctl(fd, DM_TABLE_LOAD, io)) < 0) {
LOGE("device-mapper load ioctl failed (%d)", errno);
rc = -errno;
goto out_free;
}
free(io);
if (!(io = _dm_ioctl_setup(dm, 0))) {
LOGE("Unable to setup ioctl (out of memory)");
rc = -ENOMEM;
goto out_nofree;
}
if ((rc = ioctl(fd, DM_DEV_SUSPEND, io)) < 0) {
LOGE("device-mapper resume ioctl failed (%d)", errno);
rc = -errno;
goto out_free;
}
out_free:
free (io);
out_nofree:
close (fd);
return rc;
}
static int loopback_start(struct devmapping *dm)
{
int i;
int fd;
char filename[255];
int rc;
#if DEBUG_DEVMAPPER
LOG_VOL("loopback_start(%s):", dm->type_data.loop.loop_src);
#endif
for (i = 0; i < MAX_LOOP; i++) {
struct loop_info info;
sprintf(filename, "/dev/block/loop%d", i);
if ((fd = open(filename, O_RDWR)) < 0) {
LOGE("Unable to open %s (%s)", filename, strerror(errno));
return -errno;
}
rc = ioctl(fd, LOOP_GET_STATUS, &info);
if (rc < 0 && errno == ENXIO)
break;
close(fd);
if (rc < 0) {
LOGE("Unable to get loop status for %s (%s)", filename,
strerror(errno));
return -errno;
}
}
if (i == MAX_LOOP) {
LOGE("Out of loop devices");
return -ENOSPC;
}
int file_fd;
if ((file_fd = open(dm->type_data.loop.loop_src, O_RDWR)) < 0) {
LOGE("Unable to open %s (%s)", dm->type_data.loop.loop_src,
strerror(errno));
return -errno;
}
if (ioctl(fd, LOOP_SET_FD, file_fd) < 0) {
LOGE("Error setting up loopback interface (%s)", strerror(errno));
return -errno;
}
dm->type_data.loop.loop_dev = strdup(filename);
dm->type_data.loop.loop_no = i;
close(fd);
close(file_fd);
#if DEBUG_DEVMAPPER
LOG_VOL("Loop setup on %s for %s", dm->type_data.loop.loop_dev,
dm->type_data.loop.loop_src);
#endif
return 0;
}
int devmapper_start(struct devmapping *dm)
{
int rc;
char src_blkdev_path[255];
#if DEBUG_DEVMAPPER
LOG_VOL("devmapper_start()");
#endif
if (dm->src_type == dmsrc_loopback) {
if ((rc = loopback_start(dm)) < 0)
return rc;
} else if (dm->src_type == dmsrc_partition) {
LOGE("partition maps not yet supported");
return -ENOSYS;
} else {
LOGE("devmapper_start(): Unsupported source type '%d'", dm->src_type);
return -ENOENT;
}
/*
* Configure the device mapper
*/
if ((rc = create_devmapping(dm)) < 0) {
LOGE("Failed to create devmapping (%d)", rc);
// XXX: if loopback then tear down
return rc;
}
return 0;
}
struct devmapping *devmapper_init(char *src, char *src_type, uint32_t size_mb,
char *target, char *params, char *tgt_fs, char *mediapath)
{
struct devmapping *dm;
if (!(dm = malloc(sizeof(struct devmapping)))) {
LOGE("devmapper_init(): out of memory");
return NULL;
}
memset(dm, 0, sizeof(struct devmapping));
if (!strcmp(src_type, "loopback_file")) {
dm->src_type = dmsrc_loopback;
dm->type_data.loop.loop_src = strdup(src);
} else if (!strncmp(src_type, "partition ", strlen("partition "))) {
dm->src_type = dmsrc_partition;
char *p = strtok(src_type, " ");
if (!p) {
LOGE("Invalid partition specifier");
goto out_free;
}
dm->type_data.part.part_type = strtoul(p, NULL, 0);
} else {
LOGE("Invalid src_type defined (%s)", src_type);
goto out_free;
}
// XXX: Validate these
dm->size_mb = size_mb;
dm->target = strdup(target);
dm->params = strdup(params);
dm->tgt_fs = strdup(tgt_fs);
if ((dm->dm_no = get_next_available_dm()) < 0)
goto out_free;
sprintf(mediapath, "/devices/virtual/block/dm-%d", dm->dm_no);
if (!(dm->media = media_create(mediapath,
"unknown",
"unknown",
media_devmapper))) {
LOGE("Unable to create media");
goto out_free;
}
return dm;
out_free:
if (dm->target)
free(dm->target);
if (dm->params)
free(dm->params);
if (dm->tgt_fs)
free(dm->tgt_fs);
free(dm);
return NULL;
}
int devmapper_genesis(struct devmapping *dm)
{
if (dm->src_type == dmsrc_loopback) {
int fd;
LOG_VOL("devmapper_genesis(): Working on %s",
dm->type_data.loop.loop_src);
unlink(dm->type_data.loop.loop_src);
LOG_VOL("devmapper_genesis(): Creating imagefile (%u MB)",
dm->size_mb);
if ((fd = creat(dm->type_data.loop.loop_src, 0600)) < 0) {
LOGE("Error creating imagefile (%s)", strerror(errno));
return -errno;
}
if (ftruncate(fd, (dm->size_mb * (1024 * 1024))) < 0) {
LOGE("Error truncating imagefile (%s)", strerror(errno));
close(fd);
return -errno;
}
close(fd);
} else if (dm->src_type == dmsrc_partition) {
LOGE("partition maps not yet supported");
return -ENOSYS;
}
return devmapper_start(dm);
}
static int destroy_devmapping(struct devmapping *dm)
{
struct dm_ioctl *io;
int dmFd;
int rc = 0;
LOG_VOL("destroy_devmapping():");
if ((dmFd = open("/dev/device-mapper", O_RDWR)) < 0) {
LOGE("Error opening device mapper (%d)", errno);
return -errno;
}
if (!(io = _dm_ioctl_setup(dm, DM_PERSISTENT_DEV_FLAG))) {
LOGE("Unable to setup ioctl (out of memory)");
rc = -ENOMEM;
goto out_nofree;
}
if ((rc = ioctl(dmFd, DM_DEV_REMOVE, io)) < 0) {
LOGE("device-mapper remove ioctl failed (%d)", errno);
rc = -errno;
goto out_free;
}
out_free:
free (io);
out_nofree:
close (dmFd);
return rc;
}
static int loopback_stop(struct devmapping *dm)
{
char devname[255];
int device_fd;
int rc = 0;
LOG_VOL("loopback_stop():");
device_fd = open(dm->type_data.loop.loop_dev, O_RDONLY);
if (device_fd < 0) {
LOG_ERROR("Failed to open loop (%d)", errno);
return -errno;
}
if (ioctl(device_fd, LOOP_CLR_FD, 0) < 0) {
LOG_ERROR("Failed to destroy loop (%d)", errno);
rc = -errno;
}
close(device_fd);
return rc;
}
int devmapper_stop(struct devmapping *dm)
{
int rc;
LOG_VOL("devmapper_stop():");
if ((rc = destroy_devmapping(dm)))
return rc;
if (dm->src_type == dmsrc_loopback) {
if ((rc = loopback_stop(dm)))
return rc;
} else if (dm->src_type == dmsrc_partition) {
LOGE("partition maps not yet supported");
return -ENOSYS;
}
return 0;
}
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