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() {
  29   }
  30
  31   Status LockFile(FileLock** db_lock) {
  32     return env_->LockFile(file_, db_lock);
  33   }
  34
  35   Status UnlockFile(FileLock* db_lock) {
  36     return env_->UnlockFile(db_lock);
  37   }
  38
  39   bool AssertFileIsLocked(){
  40     return CheckFileLock( /* lock_expected = */ true);
  41   }
  42
  43   bool AssertFileIsNotLocked(){
  44     return CheckFileLock( /* lock_expected = */ false);
  45   }
  46
  47   bool CheckFileLock(bool lock_expected){
  48     // We need to fork to check the fcntl lock as we need
  49     // to open and close the file from a different process
  50     // to avoid either releasing the lock on close, or not
  51     // contending for it when requesting a lock.
  52
  53 #ifdef OS_WIN
  54
  55     // WaitForSingleObject and GetExitCodeProcess can do what waitpid does.
  56     // TODO - implement on Windows
  57     return true;
  58
  59 #else
  60
  61     pid_t pid = fork();
  62     if ( 0 == pid ) {
  63       // child process
  64       int exit_val = EXIT_FAILURE;
  65       int fd = open(file_.c_str(), O_RDWR | O_CREAT, 0644);
  66       if (fd < 0) {
  67         // could not open file, could not check if it was locked
  68         fprintf( stderr, "Open on on file %s failed.\n",file_.c_str());
  69         exit(exit_val);
  70       }
  71
  72       struct flock f;
  73       memset(&f, 0, sizeof(f));
  74       f.l_type = (F_WRLCK);
  75       f.l_whence = SEEK_SET;
  76       f.l_start = 0;
  77       f.l_len = 0; // Lock/unlock entire file
  78       int value = fcntl(fd, F_SETLK, &f);
  79       if( value == -1 ){
  80         if( lock_expected ){
  81           exit_val = EXIT_SUCCESS;
  82         }
  83       } else {
  84         if( ! lock_expected ){
  85           exit_val = EXIT_SUCCESS;
  86         }
  87       }
  88       close(fd); // lock is released for child process
  89       exit(exit_val);
  90     } else if (pid > 0) {
  91       // parent process
  92       int status;
  93       while (-1 == waitpid(pid, &status, 0));
  94       if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
  95         // child process exited with non success status
  96         return false;
  97       } else {
  98         return true;
  99       }
 100     } else {
 101       fprintf( stderr, "Fork failed\n" );
 102       return false;
 103     }
 104     return false;
 105
 106 #endif
 107
 108   }
 109
 110 };
 111 LockTest* LockTest::current_;
 112
 113 TEST_F(LockTest, LockBySameThread) {
 114   FileLock* lock1;
 115   FileLock* lock2;
 116
 117   // acquire a lock on a file
 118   ASSERT_OK(LockFile(&lock1));
 119
 120   // check the file is locked
 121   ASSERT_TRUE( AssertFileIsLocked() );
 122
 123   // re-acquire the lock on the same file. This should fail.
 124   ASSERT_TRUE(LockFile(&lock2).IsIOError());
 125
 126   // check the file is locked
 127   ASSERT_TRUE( AssertFileIsLocked() );
 128
 129   // release the lock
 130   ASSERT_OK(UnlockFile(lock1));
 131
 132   // check the file is not locked
 133   ASSERT_TRUE( AssertFileIsNotLocked() );
 134
 135 }
 136
 137 }  // namespace rocksdb
 138
 139 int main(int argc, char** argv) {
 140   ::testing::InitGoogleTest(&argc, argv);
 141   return RUN_ALL_TESTS();
 142 }