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94 lines
2.7 KiB
94 lines
2.7 KiB
/* |
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* Copyright (C) 2018 The Android Open Source Project |
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* |
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* Licensed under the Apache License, Version 2.0 (the "License"); |
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* you may not use this file except in compliance with the License. |
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* You may obtain a copy of the License at |
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* |
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* http://www.apache.org/licenses/LICENSE-2.0 |
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* |
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* Unless required by applicable law or agreed to in writing, software |
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* distributed under the License is distributed on an "AS IS" BASIS, |
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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* See the License for the specific language governing permissions and |
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* limitations under the License. |
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*/ |
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#define LOG_TAG "apexd" |
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#include "apexd_private.h" |
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#include <sys/mount.h> |
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#include <sys/stat.h> |
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#include <android-base/logging.h> |
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#include <android-base/macros.h> |
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#include "string_log.h" |
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namespace android { |
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namespace apex { |
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namespace apexd_private { |
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Status BindMount(const std::string& target, const std::string& source) { |
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LOG(VERBOSE) << "Creating bind-mount for " << target << " for " << source; |
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// Ensure the directory exists, try to unmount. |
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{ |
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bool exists; |
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bool is_dir; |
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{ |
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struct stat buf; |
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if (stat(target.c_str(), &buf) != 0) { |
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if (errno == ENOENT) { |
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exists = false; |
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is_dir = false; |
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} else { |
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PLOG(ERROR) << "Could not stat target directory " << target; |
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// Still attempt to bind-mount. |
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exists = true; |
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is_dir = true; |
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} |
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} else { |
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exists = true; |
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is_dir = S_ISDIR(buf.st_mode); |
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} |
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} |
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// Ensure that it is a folder. |
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if (exists && !is_dir) { |
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LOG(WARNING) << target << " is not a directory, attempting to fix"; |
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if (unlink(target.c_str()) != 0) { |
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PLOG(ERROR) << "Failed to unlink " << target; |
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// Try mkdir, anyways. |
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} |
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exists = false; |
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} |
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// And create it if necessary. |
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if (!exists) { |
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LOG(VERBOSE) << "Creating mountpoint " << target; |
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if (mkdir(target.c_str(), kMkdirMode) != 0) { |
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return Status::Fail(PStringLog() |
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<< "Could not create mountpoint " << target); |
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} |
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}; |
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// Unmount any active bind-mount. |
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if (exists) { |
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int rc = umount2(target.c_str(), UMOUNT_NOFOLLOW | MNT_DETACH); |
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if (rc != 0 && errno != EINVAL) { |
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// Log error but ignore. |
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PLOG(ERROR) << "Could not unmount " << target; |
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} |
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} |
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} |
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LOG(VERBOSE) << "Bind-mounting " << source << " to " << target; |
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if (mount(source.c_str(), target.c_str(), nullptr, MS_BIND, nullptr) == 0) { |
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return Status::Success(); |
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} |
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return Status::Fail(PStringLog() |
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<< "Could not bind-mount " << source << " to " << target); |
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} |
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} // namespace apexd_private |
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} // namespace apex |
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} // namespace android
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