96 lines
2.7 KiB
C++
96 lines
2.7 KiB
C++
/*
|
|
* Copyright (C) 2018 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.
|
|
*/
|
|
|
|
#define LOG_TAG "apexd"
|
|
|
|
#include "apexd_private.h"
|
|
|
|
#include <sys/mount.h>
|
|
#include <sys/stat.h>
|
|
|
|
#include <android-base/logging.h>
|
|
#include <android-base/macros.h>
|
|
|
|
#include "string_log.h"
|
|
|
|
using android::base::ErrnoError;
|
|
using android::base::Result;
|
|
|
|
namespace android {
|
|
namespace apex {
|
|
namespace apexd_private {
|
|
|
|
Result<void> BindMount(const std::string& target, const std::string& source) {
|
|
LOG(VERBOSE) << "Creating bind-mount for " << target << " for " << source;
|
|
// Ensure the directory exists, try to unmount.
|
|
{
|
|
bool exists;
|
|
bool is_dir;
|
|
{
|
|
struct stat buf;
|
|
if (stat(target.c_str(), &buf) != 0) {
|
|
if (errno == ENOENT) {
|
|
exists = false;
|
|
is_dir = false;
|
|
} else {
|
|
PLOG(ERROR) << "Could not stat target directory " << target;
|
|
// Still attempt to bind-mount.
|
|
exists = true;
|
|
is_dir = true;
|
|
}
|
|
} else {
|
|
exists = true;
|
|
is_dir = S_ISDIR(buf.st_mode);
|
|
}
|
|
}
|
|
|
|
// Ensure that it is a folder.
|
|
if (exists && !is_dir) {
|
|
LOG(WARNING) << target << " is not a directory, attempting to fix";
|
|
if (unlink(target.c_str()) != 0) {
|
|
PLOG(ERROR) << "Failed to unlink " << target;
|
|
// Try mkdir, anyways.
|
|
}
|
|
exists = false;
|
|
}
|
|
// And create it if necessary.
|
|
if (!exists) {
|
|
LOG(VERBOSE) << "Creating mountpoint " << target;
|
|
if (mkdir(target.c_str(), kMkdirMode) != 0) {
|
|
return ErrnoError() << "Could not create mountpoint " << target;
|
|
}
|
|
};
|
|
// Unmount any active bind-mount.
|
|
if (exists) {
|
|
int rc = umount2(target.c_str(), UMOUNT_NOFOLLOW);
|
|
if (rc != 0 && errno != EINVAL) {
|
|
// Log error but ignore.
|
|
PLOG(ERROR) << "Could not unmount " << target;
|
|
}
|
|
}
|
|
}
|
|
|
|
LOG(VERBOSE) << "Bind-mounting " << source << " to " << target;
|
|
if (mount(source.c_str(), target.c_str(), nullptr, MS_BIND, nullptr) == 0) {
|
|
return {};
|
|
}
|
|
return ErrnoError() << "Could not bind-mount " << source << " to " << target;
|
|
}
|
|
|
|
} // namespace apexd_private
|
|
} // namespace apex
|
|
} // namespace android
|