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https://github.com/facebook/sapling.git
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104ae880db
Summary: - Catch the Windows-specific exceptions types thrown when attempting to open the socket if EdenFS is not running, and convert this to an EdenNotRunning exception. - Update EdenFS to write its pid to a separate file, in addition to the normal lock file, and have `edenfsctl` read this file instead of the lock file on Windows. Other processes cannot read the lock file while EdenFS is running and holding the lock, so it is nice to have the pid written in an alternate location. Reviewed By: pkaush Differential Revision: D20854615 fbshipit-source-id: 1c8e8f402eb17dd012d03e11fbb662f493d9362d
121 lines
3.5 KiB
C++
121 lines
3.5 KiB
C++
/*
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* Copyright (c) Facebook, Inc. and its affiliates.
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*
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* This software may be used and distributed according to the terms of the
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* GNU General Public License version 2.
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*/
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#include "eden/fs/service/EdenStateDir.h"
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#include <folly/FileUtil.h>
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#include <folly/logging/xlog.h>
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using folly::StringPiece;
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namespace {
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constexpr StringPiece kLockFileName{"lock"};
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constexpr StringPiece kPidFileName{"pid"};
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constexpr StringPiece kTakeoverSocketName{"takeover"};
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constexpr StringPiece kThriftSocketName{"socket"};
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} // namespace
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namespace facebook {
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namespace eden {
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EdenStateDir::EdenStateDir(AbsolutePathPiece path)
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: path_(path), lockPath_(path + PathComponentPiece(kLockFileName)) {}
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EdenStateDir::~EdenStateDir() {}
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bool EdenStateDir::acquireLock() {
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auto lockFile =
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folly::File(lockPath_.value(), O_WRONLY | O_CREAT | O_CLOEXEC);
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if (!lockFile.try_lock()) {
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return false;
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}
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takeoverLock(std::move(lockFile));
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return true;
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}
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void EdenStateDir::takeoverLock(folly::File lockFile) {
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writePidToLockFile(lockFile);
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int rc = fstat(lockFile.fd(), &lockFileStat_);
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folly::checkUnixError(rc, "error getting lock file attributes");
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lockFile_ = std::move(lockFile);
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// On Windows, also write the pid to a separate file.
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// Other processes cannot read the lock file while we are holding the lock,
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// so we store it in a separate file too.
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auto pidFilePath = path_ + PathComponentPiece(kPidFileName);
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folly::File pidFile(pidFilePath.c_str(), O_WRONLY | O_CREAT, 0644);
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writePidToLockFile(pidFile);
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}
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folly::File EdenStateDir::extractLock() {
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return std::move(lockFile_);
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}
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void EdenStateDir::writePidToLockFile(folly::File& lockFile) {
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// Write the PID (with a newline) to the lockfile.
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folly::ftruncateNoInt(lockFile.fd(), /* len */ 0);
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const auto pidContents = folly::to<std::string>(getpid(), "\n");
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folly::pwriteNoInt(lockFile.fd(), pidContents.data(), pidContents.size(), 0);
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}
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bool EdenStateDir::isLocked() const {
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// We only set lockFile_ once we have locked it,
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// so as long as this is set we have the lock.
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return bool(lockFile_);
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}
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bool EdenStateDir::isLockValid() const {
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if (!lockFile_) {
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return false;
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}
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// The st_dev and st_ino fields aren't valid on Windows, so skip the check
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// to see if the lock file is still valid. Assume that if we acquired it
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// initially it is still valid.
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//
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// Windows generally makes it harder for users to delete or rename the
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// directory out from under an existing process while we have file handles
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// open, so this check isn't really as necessary.
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#ifndef _WIN32
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struct stat st;
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int rc = stat(lockPath_.c_str(), &st);
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if (rc != 0) {
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int errnum = errno;
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XLOG(ERR) << "EdenFS lock file no longer appears valid: "
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"failed to stat lock file: "
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<< folly::errnoStr(errnum);
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return false;
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}
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bool isSameFile =
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(st.st_dev == lockFileStat_.st_dev && st.st_ino == lockFileStat_.st_ino);
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if (!isSameFile) {
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XLOG(ERR) << "EdenFS lock file no longer appears valid: "
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"file has been replaced";
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return false;
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}
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#endif
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return true;
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}
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AbsolutePath EdenStateDir::getThriftSocketPath() const {
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return path_ + PathComponentPiece{kThriftSocketName};
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}
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AbsolutePath EdenStateDir::getTakeoverSocketPath() const {
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return path_ + PathComponentPiece{kTakeoverSocketName};
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}
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AbsolutePath EdenStateDir::getCheckoutStateDir(StringPiece checkoutID) const {
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return path_ + PathComponent("clients") + PathComponent(checkoutID);
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}
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} // namespace eden
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} // namespace facebook
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