diff options
Diffstat (limited to 'Devmapper.cpp')
-rw-r--r-- | Devmapper.cpp | 210 |
1 files changed, 210 insertions, 0 deletions
diff --git a/Devmapper.cpp b/Devmapper.cpp new file mode 100644 index 0000000..2b7d9a0 --- /dev/null +++ b/Devmapper.cpp @@ -0,0 +1,210 @@ +/* + * 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 <fcntl.h> +#include <unistd.h> +#include <errno.h> +#include <string.h> + +#include <sys/types.h> +#include <sys/ioctl.h> +#include <sys/stat.h> + +#define LOG_TAG "Vold" + +#include <cutils/log.h> + +#include "Devmapper.h" + +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; + strncpy(io->name, name, sizeof(io->name)); +} + +int Devmapper::lookupActive(const char *name, char *ubuffer, size_t len) { + char *buffer = (char *) malloc(4096); + if (!buffer) { + LOGE("Error allocating memory (%s)", strerror(errno)); + return -1; + } + + int fd; + if ((fd = open("/dev/device-mapper", O_RDWR)) < 0) { + LOGE("Error opening devmapper (%s)", strerror(errno)); + free(buffer); + return -1; + } + + struct dm_ioctl *io = (struct dm_ioctl *) buffer; + + ioctlInit(io, 4096, name, 0); + if (ioctl(fd, DM_DEV_STATUS, io)) { + if (errno != ENODEV) { + LOGE("Error retrieving device status (%s)", strerror(errno)); + } + free(buffer); + close(fd); + return -1; + } + close(fd); + + unsigned minor = (io->dev & 0xff) | ((io->dev >> 12) & 0xfff00); + free(buffer); + LOGD("Newly created devmapper instance minor = %d\n", minor); + snprintf(ubuffer, len, "/dev/block/dm-%u", minor); + return 0; +} + +int Devmapper::create(const char *name, const char *loopFile, const char *key, int sizeMb, + char *ubuffer, size_t len) { + char *buffer = (char *) malloc(4096); + if (!buffer) { + LOGE("Error allocating memory (%s)", strerror(errno)); + return -1; + } + + int fd; + if ((fd = open("/dev/device-mapper", O_RDWR)) < 0) { + LOGE("Error opening devmapper (%s)", strerror(errno)); + free(buffer); + return -1; + } + + struct dm_ioctl *io = (struct dm_ioctl *) buffer; + + // Create the DM device + ioctlInit(io, 4096, name, 0); + + if (ioctl(fd, DM_DEV_CREATE, io)) { + LOGE("Error creating device mapping (%s)", strerror(errno)); + free(buffer); + close(fd); + return -1; + } + + // Set the legacy geometry + ioctlInit(io, 4096, 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 + strcpy(geoParams, "0 64 63 0"); + geoParams += strlen(geoParams) + 1; + geoParams = (char *) _align(geoParams, 8); + if (ioctl(fd, DM_DEV_SET_GEOMETRY, io)) { + LOGE("Error setting device geometry (%s)", strerror(errno)); + free(buffer); + close(fd); + return -1; + } + + // Retrieve the device number we were allocated + ioctlInit(io, 4096, name, 0); + if (ioctl(fd, DM_DEV_STATUS, io)) { + LOGE("Error retrieving device status (%s)", strerror(errno)); + free(buffer); + close(fd); + return -1; + } + + unsigned minor = (io->dev & 0xff) | ((io->dev >> 12) & 0xfff00); + LOGD("Newly created devmapper instance minor = %d\n", minor); + 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, 4096, name, DM_STATUS_TABLE_FLAG); + io->target_count = 1; + tgt->status = 0; + tgt->sector_start = 0; + tgt->length = (sizeMb * (1024 * 1024)) / 512; + strcpy(tgt->target_type, "crypt"); + + char *cryptParams = buffer + sizeof(struct dm_ioctl) + sizeof(struct dm_target_spec); + sprintf(cryptParams, "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)) { + LOGE("Error loading mapping table (%s)", strerror(errno)); + free(buffer); + close(fd); + return -1; + } + + // Resume the new table + ioctlInit(io, 4096, name, 0); + + if (ioctl(fd, DM_DEV_SUSPEND, io)) { + LOGE("Error Resuming (%s)", strerror(errno)); + free(buffer); + close(fd); + return -1; + } + + free(buffer); + + return 0; +} + +int Devmapper::destroy(const char *name) { + char *buffer = (char *) malloc(4096); + if (!buffer) { + LOGE("Error allocating memory (%s)", strerror(errno)); + return -1; + } + + int fd; + if ((fd = open("/dev/device-mapper", O_RDWR)) < 0) { + LOGE("Error opening devmapper (%s)", strerror(errno)); + free(buffer); + return -1; + } + + struct dm_ioctl *io = (struct dm_ioctl *) buffer; + + // Create the DM device + ioctlInit(io, 4096, name, 0); + + if (ioctl(fd, DM_DEV_REMOVE, io)) { + LOGE("Error destroying device mapping (%s)", strerror(errno)); + free(buffer); + close(fd); + return -1; + } + + free(buffer); + close(fd); + return 0; +} + +void *Devmapper::_align(void *ptr, unsigned int a) +{ + register unsigned long agn = --a; + + return (void *) (((unsigned long) ptr + agn) & ~agn); +} + |