blob: ed498a3a383149d2801a8a3383863cfbe55890ce [file] [log] [blame]
/*
* 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 <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <linux/kdev_t.h>
#define LOG_TAG "Vold"
#include <cutils/log.h>
#include <android-base/logging.h>
#include <android-base/stringprintf.h>
#include "Devmapper.h"
#define DEVMAPPER_BUFFER_SIZE 4096
using android::base::StringPrintf;
static const char* kVoldPrefix = "vold:";
void Devmapper::ioctlInit(struct dm_ioctl *io, size_t dataSize,
const char *name, unsigned flags) {
memset(io, 0, dataSize);
io->data_size = dataSize;
io->data_start = sizeof(struct dm_ioctl);
io->version[0] = 4;
io->version[1] = 0;
io->version[2] = 0;
io->flags = flags;
if (name) {
size_t ret = strlcpy(io->name, name, sizeof(io->name));
if (ret >= sizeof(io->name))
abort();
}
}
int Devmapper::lookupActive(const char *name_raw, char *ubuffer, size_t len) {
auto name_string = StringPrintf("%s%s", kVoldPrefix, name_raw);
const char* name = name_string.c_str();
char *buffer = (char *) malloc(DEVMAPPER_BUFFER_SIZE);
if (!buffer) {
SLOGE("Error allocating memory (%s)", strerror(errno));
return -1;
}
int fd;
if ((fd = open("/dev/device-mapper", O_RDWR | O_CLOEXEC)) < 0) {
SLOGE("Error opening devmapper (%s)", strerror(errno));
free(buffer);
return -1;
}
struct dm_ioctl *io = (struct dm_ioctl *) buffer;
ioctlInit(io, DEVMAPPER_BUFFER_SIZE, name, 0);
if (ioctl(fd, DM_DEV_STATUS, io)) {
if (errno != ENXIO) {
SLOGE("DM_DEV_STATUS ioctl failed for lookup (%s)", strerror(errno));
}
free(buffer);
close(fd);
return -1;
}
close(fd);
unsigned minor = (io->dev & 0xff) | ((io->dev >> 12) & 0xfff00);
free(buffer);
snprintf(ubuffer, len, "/dev/block/dm-%u", minor);
return 0;
}
int Devmapper::create(const char *name_raw, const char *loopFile, const char *key,
unsigned long numSectors, char *ubuffer, size_t len) {
auto name_string = StringPrintf("%s%s", kVoldPrefix, name_raw);
const char* name = name_string.c_str();
char *buffer = (char *) malloc(DEVMAPPER_BUFFER_SIZE);
if (!buffer) {
SLOGE("Error allocating memory (%s)", strerror(errno));
return -1;
}
int fd;
if ((fd = open("/dev/device-mapper", O_RDWR | O_CLOEXEC)) < 0) {
SLOGE("Error opening devmapper (%s)", strerror(errno));
free(buffer);
return -1;
}
struct dm_ioctl *io = (struct dm_ioctl *) buffer;
// Create the DM device
ioctlInit(io, DEVMAPPER_BUFFER_SIZE, name, 0);
if (ioctl(fd, DM_DEV_CREATE, io)) {
SLOGE("Error creating device mapping (%s)", strerror(errno));
free(buffer);
close(fd);
return -1;
}
// Set the legacy geometry
ioctlInit(io, DEVMAPPER_BUFFER_SIZE, name, 0);
char *geoParams = buffer + sizeof(struct dm_ioctl);
// bps=512 spc=8 res=32 nft=2 sec=8190 mid=0xf0 spt=63 hds=64 hid=0 bspf=8 rdcl=2 infs=1 bkbs=2
strlcpy(geoParams, "0 64 63 0", DEVMAPPER_BUFFER_SIZE - sizeof(struct dm_ioctl));
geoParams += strlen(geoParams) + 1;
geoParams = (char *) _align(geoParams, 8);
if (ioctl(fd, DM_DEV_SET_GEOMETRY, io)) {
SLOGE("Error setting device geometry (%s)", strerror(errno));
free(buffer);
close(fd);
return -1;
}
// Retrieve the device number we were allocated
ioctlInit(io, DEVMAPPER_BUFFER_SIZE, name, 0);
if (ioctl(fd, DM_DEV_STATUS, io)) {
SLOGE("Error retrieving devmapper status (%s)", strerror(errno));
free(buffer);
close(fd);
return -1;
}
unsigned minor = (io->dev & 0xff) | ((io->dev >> 12) & 0xfff00);
snprintf(ubuffer, len, "/dev/block/dm-%u", minor);
// Load the table
struct dm_target_spec *tgt;
tgt = (struct dm_target_spec *) &buffer[sizeof(struct dm_ioctl)];
ioctlInit(io, DEVMAPPER_BUFFER_SIZE, name, DM_STATUS_TABLE_FLAG);
io->target_count = 1;
tgt->status = 0;
tgt->sector_start = 0;
tgt->length = numSectors;
strlcpy(tgt->target_type, "crypt", sizeof(tgt->target_type));
char *cryptParams = buffer + sizeof(struct dm_ioctl) + sizeof(struct dm_target_spec);
snprintf(cryptParams,
DEVMAPPER_BUFFER_SIZE - (sizeof(struct dm_ioctl) + sizeof(struct dm_target_spec)),
"twofish %s 0 %s 0", key, loopFile);
cryptParams += strlen(cryptParams) + 1;
cryptParams = (char *) _align(cryptParams, 8);
tgt->next = cryptParams - buffer;
if (ioctl(fd, DM_TABLE_LOAD, io)) {
SLOGE("Error loading mapping table (%s)", strerror(errno));
free(buffer);
close(fd);
return -1;
}
// Resume the new table
ioctlInit(io, DEVMAPPER_BUFFER_SIZE, name, 0);
if (ioctl(fd, DM_DEV_SUSPEND, io)) {
SLOGE("Error Resuming (%s)", strerror(errno));
free(buffer);
close(fd);
return -1;
}
free(buffer);
close(fd);
return 0;
}
int Devmapper::destroy(const char *name_raw) {
auto name_string = StringPrintf("%s%s", kVoldPrefix, name_raw);
const char* name = name_string.c_str();
char *buffer = (char *) malloc(DEVMAPPER_BUFFER_SIZE);
if (!buffer) {
SLOGE("Error allocating memory (%s)", strerror(errno));
return -1;
}
int fd;
if ((fd = open("/dev/device-mapper", O_RDWR | O_CLOEXEC)) < 0) {
SLOGE("Error opening devmapper (%s)", strerror(errno));
free(buffer);
return -1;
}
struct dm_ioctl *io = (struct dm_ioctl *) buffer;
// Create the DM device
ioctlInit(io, DEVMAPPER_BUFFER_SIZE, name, 0);
if (ioctl(fd, DM_DEV_REMOVE, io)) {
if (errno != ENXIO) {
SLOGE("Error destroying device mapping (%s)", strerror(errno));
}
free(buffer);
close(fd);
return -1;
}
free(buffer);
close(fd);
return 0;
}
int Devmapper::destroyAll() {
char *buffer = (char *) malloc(1024 * 64);
if (!buffer) {
SLOGE("Error allocating memory (%s)", strerror(errno));
return -1;
}
memset(buffer, 0, (1024 * 64));
char *buffer2 = (char *) malloc(DEVMAPPER_BUFFER_SIZE);
if (!buffer2) {
SLOGE("Error allocating memory (%s)", strerror(errno));
free(buffer);
return -1;
}
int fd;
if ((fd = open("/dev/device-mapper", O_RDWR | O_CLOEXEC)) < 0) {
SLOGE("Error opening devmapper (%s)", strerror(errno));
free(buffer);
free(buffer2);
return -1;
}
struct dm_ioctl *io = (struct dm_ioctl *) buffer;
ioctlInit(io, (1024 * 64), NULL, 0);
if (ioctl(fd, DM_LIST_DEVICES, io)) {
SLOGE("DM_LIST_DEVICES ioctl failed (%s)", strerror(errno));
free(buffer);
free(buffer2);
close(fd);
return -1;
}
struct dm_name_list *n = (struct dm_name_list *) (((char *) buffer) + io->data_start);
if (!n->dev) {
free(buffer);
free(buffer2);
close(fd);
return 0;
}
unsigned nxt = 0;
do {
n = (struct dm_name_list *) (((char *) n) + nxt);
if (strncmp(n->name, kVoldPrefix, strlen(kVoldPrefix)) == 0) {
LOG(DEBUG) << "Tearing down stale dm device named " << n->name;
memset(buffer2, 0, DEVMAPPER_BUFFER_SIZE);
struct dm_ioctl *io2 = (struct dm_ioctl *) buffer2;
ioctlInit(io2, DEVMAPPER_BUFFER_SIZE, n->name, 0);
if (ioctl(fd, DM_DEV_REMOVE, io2)) {
if (errno != ENXIO) {
PLOG(WARNING) << "Failed to destroy dm device named " << n->name;
}
}
} else {
LOG(VERBOSE) << "Found unmanaged dm device named " << n->name;
}
nxt = n->next;
} while (nxt);
free(buffer);
free(buffer2);
close(fd);
return 0;
}
void *Devmapper::_align(void *ptr, unsigned int a)
{
unsigned long agn = --a;
return (void *) (((unsigned long) ptr + agn) & ~agn);
}