ceph/src/rocksdb/util/filelock_test.cc

   1 //  Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
   2 //  This source code is licensed under both the GPLv2 (found in the
   3 //  COPYING file in the root directory) and Apache 2.0 License
   4 //  (found in the LICENSE.Apache file in the root directory).
   5 //
   6 #include "rocksdb/status.h"
   7 #include "rocksdb/env.h"
   8
   9 #include <vector>
  10 #include <fcntl.h>
  11 #include "util/coding.h"
  12 #include "util/testharness.h"
  13
  14 namespace rocksdb {
  15
  16 class LockTest : public testing::Test {
  17  public:
  18   static LockTest* current_;
  19   std::string file_;
  20   rocksdb::Env* env_;
  21
  22   LockTest()
  23       : file_(test::PerThreadDBPath("db_testlock_file")),
  24         env_(rocksdb::Env::Default()) {
  25     current_ = this;
  26   }
  27
  28   ~LockTest() override {}
  29
  30   Status LockFile(FileLock** db_lock) {
  31     return env_->LockFile(file_, db_lock);
  32   }
  33
  34   Status UnlockFile(FileLock* db_lock) {
  35     return env_->UnlockFile(db_lock);
  36   }
  37
  38   bool AssertFileIsLocked(){
  39     return CheckFileLock( /* lock_expected = */ true);
  40   }
  41
  42   bool AssertFileIsNotLocked(){
  43     return CheckFileLock( /* lock_expected = */ false);
  44   }
  45
  46   bool CheckFileLock(bool lock_expected){
  47     // We need to fork to check the fcntl lock as we need
  48     // to open and close the file from a different process
  49     // to avoid either releasing the lock on close, or not
  50     // contending for it when requesting a lock.
  51
  52 #ifdef OS_WIN
  53
  54     // WaitForSingleObject and GetExitCodeProcess can do what waitpid does.
  55     // TODO - implement on Windows
  56     return true;
  57
  58 #else
  59
  60     pid_t pid = fork();
  61     if ( 0 == pid ) {
  62       // child process
  63       int exit_val = EXIT_FAILURE;
  64       int fd = open(file_.c_str(), O_RDWR | O_CREAT, 0644);
  65       if (fd < 0) {
  66         // could not open file, could not check if it was locked
  67         fprintf( stderr, "Open on on file %s failed.\n",file_.c_str());
  68         exit(exit_val);
  69       }
  70
  71       struct flock f;
  72       memset(&f, 0, sizeof(f));
  73       f.l_type = (F_WRLCK);
  74       f.l_whence = SEEK_SET;
  75       f.l_start = 0;
  76       f.l_len = 0; // Lock/unlock entire file
  77       int value = fcntl(fd, F_SETLK, &f);
  78       if( value == -1 ){
  79         if( lock_expected ){
  80           exit_val = EXIT_SUCCESS;
  81         }
  82       } else {
  83         if( ! lock_expected ){
  84           exit_val = EXIT_SUCCESS;
  85         }
  86       }
  87       close(fd); // lock is released for child process
  88       exit(exit_val);
  89     } else if (pid > 0) {
  90       // parent process
  91       int status;
  92       while (-1 == waitpid(pid, &status, 0));
  93       if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
  94         // child process exited with non success status
  95         return false;
  96       } else {
  97         return true;
  98       }
  99     } else {
 100       fprintf( stderr, "Fork failed\n" );
 101       return false;
 102     }
 103     return false;
 104
 105 #endif
 106
 107   }
 108
 109 };
 110 LockTest* LockTest::current_;
 111
 112 TEST_F(LockTest, LockBySameThread) {
 113   FileLock* lock1;
 114   FileLock* lock2;
 115
 116   // acquire a lock on a file
 117   ASSERT_OK(LockFile(&lock1));
 118
 119   // check the file is locked
 120   ASSERT_TRUE( AssertFileIsLocked() );
 121
 122   // re-acquire the lock on the same file. This should fail.
 123   ASSERT_TRUE(LockFile(&lock2).IsIOError());
 124
 125   // check the file is locked
 126   ASSERT_TRUE( AssertFileIsLocked() );
 127
 128   // release the lock
 129   ASSERT_OK(UnlockFile(lock1));
 130
 131   // check the file is not locked
 132   ASSERT_TRUE( AssertFileIsNotLocked() );
 133
 134 }
 135
 136 }  // namespace rocksdb
 137
 138 int main(int argc, char** argv) {
 139   ::testing::InitGoogleTest(&argc, argv);
 140   return RUN_ALL_TESTS();
 141 }