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platform_system_vold/Loop.cpp
Jeff Sharkey ce6a913aea Exclusive exec() path, format after partition. 
Sadly setexeccon() is process global, so we need to carefully ensure
that all exec() are mutually exclusive to avoid transitioning into
unwanted domains.  Also, because we have several threads floating
around, we need to guard all our FDs with O_CLOEXEC.

Format all newly created volumes immediately after partitioning,
but silence all events emitted from those volumes to prevent the
framework from getting all excited.  Unify all notify events under a
single codepath to make them easy to silence.

Sent SIGINT before escalating to SIGTERM when unmounting.

Bug: 19993667
Change-Id: Idc6c806afc7919a004a93e2240b42884f6b52d6b
2015-04-11 08:48:13 -07:00

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8.8 KiB
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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 <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <sys/mount.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <linux/kdev_t.h>
#define LOG_TAG "Vold"
#include <cutils/log.h>
#include <sysutils/SocketClient.h>
#include "Loop.h"
#include "Asec.h"
#include "VoldUtil.h"
#include "sehandle.h"
int Loop::dumpState(SocketClient *c) {
int i;
int fd;
char filename[256];
for (i = 0; i < LOOP_MAX; i++) {
struct loop_info64 li;
int rc;
sprintf(filename, "/dev/block/loop%d", i);
if ((fd = open(filename, O_RDWR | O_CLOEXEC)) < 0) {
if (errno != ENOENT) {
SLOGE("Unable to open %s (%s)", filename, strerror(errno));
} else {
continue;
}
return -1;
}
rc = ioctl(fd, LOOP_GET_STATUS64, &li);
close(fd);
if (rc < 0 && errno == ENXIO) {
continue;
}
if (rc < 0) {
SLOGE("Unable to get loop status for %s (%s)", filename,
strerror(errno));
return -1;
}
char *tmp = NULL;
asprintf(&tmp, "%s %d %lld:%lld %llu %lld:%lld %lld 0x%x {%s} {%s}", filename, li.lo_number,
MAJOR(li.lo_device), MINOR(li.lo_device), li.lo_inode, MAJOR(li.lo_rdevice),
MINOR(li.lo_rdevice), li.lo_offset, li.lo_flags, li.lo_crypt_name,
li.lo_file_name);
c->sendMsg(0, tmp, false);
free(tmp);
}
return 0;
}
int Loop::lookupActive(const char *id, char *buffer, size_t len) {
int i;
int fd;
char filename[256];
memset(buffer, 0, len);
for (i = 0; i < LOOP_MAX; i++) {
struct loop_info64 li;
int rc;
sprintf(filename, "/dev/block/loop%d", i);
if ((fd = open(filename, O_RDWR | O_CLOEXEC)) < 0) {
if (errno != ENOENT) {
SLOGE("Unable to open %s (%s)", filename, strerror(errno));
} else {
continue;
}
return -1;
}
rc = ioctl(fd, LOOP_GET_STATUS64, &li);
close(fd);
if (rc < 0 && errno == ENXIO) {
continue;
}
if (rc < 0) {
SLOGE("Unable to get loop status for %s (%s)", filename,
strerror(errno));
return -1;
}
if (!strncmp((const char*) li.lo_crypt_name, id, LO_NAME_SIZE)) {
break;
}
}
if (i == LOOP_MAX) {
errno = ENOENT;
return -1;
}
strlcpy(buffer, filename, len);
return 0;
}
int Loop::create(const char *id, const char *loopFile, char *loopDeviceBuffer, size_t len) {
int i;
int fd;
char filename[256];
for (i = 0; i < LOOP_MAX; i++) {
struct loop_info64 li;
int rc;
char *secontext = NULL;
sprintf(filename, "/dev/block/loop%d", i);
/*
* The kernel starts us off with 8 loop nodes, but more
* are created on-demand if needed.
*/
mode_t mode = 0660 | S_IFBLK;
unsigned int dev = (0xff & i) | ((i << 12) & 0xfff00000) | (7 << 8);
if (sehandle) {
rc = selabel_lookup(sehandle, &secontext, filename, S_IFBLK);
if (rc == 0)
setfscreatecon(secontext);
}
if (mknod(filename, mode, dev) < 0) {
if (errno != EEXIST) {
int sverrno = errno;
SLOGE("Error creating loop device node (%s)", strerror(errno));
if (secontext) {
freecon(secontext);
setfscreatecon(NULL);
}
errno = sverrno;
return -1;
}
}
if (secontext) {
freecon(secontext);
setfscreatecon(NULL);
}
if ((fd = open(filename, O_RDWR | O_CLOEXEC)) < 0) {
SLOGE("Unable to open %s (%s)", filename, strerror(errno));
return -1;
}
rc = ioctl(fd, LOOP_GET_STATUS64, &li);
if (rc < 0 && errno == ENXIO)
break;
close(fd);
if (rc < 0) {
SLOGE("Unable to get loop status for %s (%s)", filename,
strerror(errno));
return -1;
}
}
if (i == LOOP_MAX) {
SLOGE("Exhausted all loop devices");
errno = ENOSPC;
return -1;
}
strlcpy(loopDeviceBuffer, filename, len);
int file_fd;
if ((file_fd = open(loopFile, O_RDWR | O_CLOEXEC)) < 0) {
SLOGE("Unable to open %s (%s)", loopFile, strerror(errno));
close(fd);
return -1;
}
if (ioctl(fd, LOOP_SET_FD, file_fd) < 0) {
SLOGE("Error setting up loopback interface (%s)", strerror(errno));
close(file_fd);
close(fd);
return -1;
}
struct loop_info64 li;
memset(&li, 0, sizeof(li));
strlcpy((char*) li.lo_crypt_name, id, LO_NAME_SIZE);
strlcpy((char*) li.lo_file_name, loopFile, LO_NAME_SIZE);
if (ioctl(fd, LOOP_SET_STATUS64, &li) < 0) {
SLOGE("Error setting loopback status (%s)", strerror(errno));
close(file_fd);
close(fd);
return -1;
}
close(fd);
close(file_fd);
return 0;
}
int Loop::destroyByDevice(const char *loopDevice) {
int device_fd;
device_fd = open(loopDevice, O_RDONLY | O_CLOEXEC);
if (device_fd < 0) {
SLOGE("Failed to open loop (%d)", errno);
return -1;
}
if (ioctl(device_fd, LOOP_CLR_FD, 0) < 0) {
SLOGE("Failed to destroy loop (%d)", errno);
close(device_fd);
return -1;
}
close(device_fd);
return 0;
}
int Loop::destroyByFile(const char * /*loopFile*/) {
errno = ENOSYS;
return -1;
}
int Loop::createImageFile(const char *file, unsigned int numSectors) {
int fd;
if ((fd = creat(file, 0600)) < 0) {
SLOGE("Error creating imagefile (%s)", strerror(errno));
return -1;
}
if (ftruncate(fd, numSectors * 512) < 0) {
SLOGE("Error truncating imagefile (%s)", strerror(errno));
close(fd);
return -1;
}
close(fd);
return 0;
}
int Loop::resizeImageFile(const char *file, unsigned int numSectors) {
int fd;
if ((fd = open(file, O_RDWR | O_CLOEXEC)) < 0) {
SLOGE("Error opening imagefile (%s)", strerror(errno));
return -1;
}
SLOGD("Attempting to increase size of %s to %d sectors.", file, numSectors);
if (fallocate(fd, 0, 0, numSectors * 512)) {
if (errno == ENOSYS || errno == ENOTSUP) {
SLOGW("fallocate not found. Falling back to ftruncate.");
if (ftruncate(fd, numSectors * 512) < 0) {
SLOGE("Error truncating imagefile (%s)", strerror(errno));
close(fd);
return -1;
}
} else {
SLOGE("Error allocating space (%s)", strerror(errno));
close(fd);
return -1;
}
}
close(fd);
return 0;
}
int Loop::lookupInfo(const char *loopDevice, struct asec_superblock *sb, unsigned long *nr_sec) {
int fd;
struct asec_superblock buffer;
if ((fd = open(loopDevice, O_RDONLY | O_CLOEXEC)) < 0) {
SLOGE("Failed to open loopdevice (%s)", strerror(errno));
destroyByDevice(loopDevice);
return -1;
}
get_blkdev_size(fd, nr_sec);
if (*nr_sec == 0) {
SLOGE("Failed to get loop size (%s)", strerror(errno));
destroyByDevice(loopDevice);
close(fd);
return -1;
}
/*
* Try to read superblock.
*/
memset(&buffer, 0, sizeof(struct asec_superblock));
if (lseek(fd, ((*nr_sec - 1) * 512), SEEK_SET) < 0) {
SLOGE("lseek failed (%s)", strerror(errno));
close(fd);
destroyByDevice(loopDevice);
return -1;
}
if (read(fd, &buffer, sizeof(struct asec_superblock)) != sizeof(struct asec_superblock)) {
SLOGE("superblock read failed (%s)", strerror(errno));
close(fd);
destroyByDevice(loopDevice);
return -1;
}
close(fd);
/*
* Superblock successfully read. Copy to caller's struct.
*/
memcpy(sb, &buffer, sizeof(struct asec_superblock));
return 0;
}
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