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// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
// This source code is licensed under both the GPLv2 (found in the
// COPYING file in the root directory) and Apache 2.0 License
// (found in the LICENSE.Apache file in the root directory).
//
#include "rocksdb/status.h"
#include "rocksdb/env.h"
#include <fcntl.h>
#include <vector>
#include "test_util/testharness.h"
#include "util/coding.h"
namespace ROCKSDB_NAMESPACE {
class LockTest : public testing::Test {
public:
static LockTest* current_;
std::string file_;
ROCKSDB_NAMESPACE::Env* env_;
LockTest()
: file_(test::PerThreadDBPath("db_testlock_file")),
env_(ROCKSDB_NAMESPACE::Env::Default()) {
current_ = this;
}
~LockTest() override {}
Status LockFile(FileLock** db_lock) {
return env_->LockFile(file_, db_lock);
}
Status UnlockFile(FileLock* db_lock) {
return env_->UnlockFile(db_lock);
}
bool AssertFileIsLocked(){
return CheckFileLock( /* lock_expected = */ true);
}
bool AssertFileIsNotLocked(){
return CheckFileLock( /* lock_expected = */ false);
}
bool CheckFileLock(bool lock_expected){
// We need to fork to check the fcntl lock as we need
// to open and close the file from a different process
// to avoid either releasing the lock on close, or not
// contending for it when requesting a lock.
#ifdef OS_WIN
// WaitForSingleObject and GetExitCodeProcess can do what waitpid does.
// TODO - implement on Windows
return true;
#else
pid_t pid = fork();
if ( 0 == pid ) {
// child process
int exit_val = EXIT_FAILURE;
int fd = open(file_.c_str(), O_RDWR | O_CREAT, 0644);
if (fd < 0) {
// could not open file, could not check if it was locked
fprintf( stderr, "Open on on file %s failed.\n",file_.c_str());
exit(exit_val);
}
struct flock f;
memset(&f, 0, sizeof(f));
f.l_type = (F_WRLCK);
f.l_whence = SEEK_SET;
f.l_start = 0;
f.l_len = 0; // Lock/unlock entire file
int value = fcntl(fd, F_SETLK, &f);
if( value == -1 ){
if( lock_expected ){
exit_val = EXIT_SUCCESS;
}
} else {
if( ! lock_expected ){
exit_val = EXIT_SUCCESS;
}
}
close(fd); // lock is released for child process
exit(exit_val);
} else if (pid > 0) {
// parent process
int status;
while (-1 == waitpid(pid, &status, 0));
if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
// child process exited with non success status
return false;
} else {
return true;
}
} else {
fprintf( stderr, "Fork failed\n" );
return false;
}
return false;
#endif
}
};
LockTest* LockTest::current_;
TEST_F(LockTest, LockBySameThread) {
FileLock* lock1;
FileLock* lock2;
// acquire a lock on a file
ASSERT_OK(LockFile(&lock1));
// check the file is locked
ASSERT_TRUE( AssertFileIsLocked() );
// re-acquire the lock on the same file. This should fail.
ASSERT_TRUE(LockFile(&lock2).IsIOError());
// check the file is locked
ASSERT_TRUE( AssertFileIsLocked() );
// release the lock
ASSERT_OK(UnlockFile(lock1));
// check the file is not locked
ASSERT_TRUE( AssertFileIsNotLocked() );
}
} // namespace ROCKSDB_NAMESPACE
int main(int argc, char** argv) {
::testing::InitGoogleTest(&argc, argv);
return RUN_ALL_TESTS();
}
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