| // Copyright (c) 2011 The LevelDB Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. See the AUTHORS file for names of contributors. |
| |
| #include <dirent.h> |
| #include <errno.h> |
| #include <fcntl.h> |
| #include <pthread.h> |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <string.h> |
| #include <sys/mman.h> |
| #include <sys/stat.h> |
| #include <sys/time.h> |
| #include <sys/types.h> |
| #include <time.h> |
| #include <unistd.h> |
| #include <deque> |
| #include <set> |
| #include "leveldb/env.h" |
| #include "leveldb/slice.h" |
| #include "port/port.h" |
| #include "util/logging.h" |
| #include "util/mutexlock.h" |
| #include "util/posix_logger.h" |
| |
| namespace leveldb { |
| |
| namespace { |
| |
| static Status IOError(const std::string& context, int err_number) { |
| return Status::IOError(context, strerror(err_number)); |
| } |
| |
| class PosixSequentialFile: public SequentialFile { |
| private: |
| std::string filename_; |
| FILE* file_; |
| |
| public: |
| PosixSequentialFile(const std::string& fname, FILE* f) |
| : filename_(fname), file_(f) { } |
| virtual ~PosixSequentialFile() { fclose(file_); } |
| |
| virtual Status Read(size_t n, Slice* result, char* scratch) { |
| Status s; |
| size_t r = fread_unlocked(scratch, 1, n, file_); |
| *result = Slice(scratch, r); |
| if (r < n) { |
| if (feof(file_)) { |
| // We leave status as ok if we hit the end of the file |
| } else { |
| // A partial read with an error: return a non-ok status |
| s = IOError(filename_, errno); |
| } |
| } |
| return s; |
| } |
| |
| virtual Status Skip(uint64_t n) { |
| if (fseek(file_, n, SEEK_CUR)) { |
| return IOError(filename_, errno); |
| } |
| return Status::OK(); |
| } |
| }; |
| |
| // pread() based random-access |
| class PosixRandomAccessFile: public RandomAccessFile { |
| private: |
| std::string filename_; |
| int fd_; |
| |
| public: |
| PosixRandomAccessFile(const std::string& fname, int fd) |
| : filename_(fname), fd_(fd) { } |
| virtual ~PosixRandomAccessFile() { close(fd_); } |
| |
| virtual Status Read(uint64_t offset, size_t n, Slice* result, |
| char* scratch) const { |
| Status s; |
| ssize_t r = pread(fd_, scratch, n, static_cast<off_t>(offset)); |
| *result = Slice(scratch, (r < 0) ? 0 : r); |
| if (r < 0) { |
| // An error: return a non-ok status |
| s = IOError(filename_, errno); |
| } |
| return s; |
| } |
| }; |
| |
| // Helper class to limit mmap file usage so that we do not end up |
| // running out virtual memory or running into kernel performance |
| // problems for very large databases. |
| class MmapLimiter { |
| public: |
| // Up to 1000 mmaps for 64-bit binaries; none for smaller pointer sizes. |
| MmapLimiter() { |
| SetAllowed(sizeof(void*) >= 8 ? 1000 : 0); |
| } |
| |
| // If another mmap slot is available, acquire it and return true. |
| // Else return false. |
| bool Acquire() { |
| if (GetAllowed() <= 0) { |
| return false; |
| } |
| MutexLock l(&mu_); |
| intptr_t x = GetAllowed(); |
| if (x <= 0) { |
| return false; |
| } else { |
| SetAllowed(x - 1); |
| return true; |
| } |
| } |
| |
| // Release a slot acquired by a previous call to Acquire() that returned true. |
| void Release() { |
| MutexLock l(&mu_); |
| SetAllowed(GetAllowed() + 1); |
| } |
| |
| private: |
| port::Mutex mu_; |
| port::AtomicPointer allowed_; |
| |
| intptr_t GetAllowed() const { |
| return reinterpret_cast<intptr_t>(allowed_.Acquire_Load()); |
| } |
| |
| // REQUIRES: mu_ must be held |
| void SetAllowed(intptr_t v) { |
| allowed_.Release_Store(reinterpret_cast<void*>(v)); |
| } |
| |
| MmapLimiter(const MmapLimiter&); |
| void operator=(const MmapLimiter&); |
| }; |
| |
| // mmap() based random-access |
| class PosixMmapReadableFile: public RandomAccessFile { |
| private: |
| std::string filename_; |
| void* mmapped_region_; |
| size_t length_; |
| MmapLimiter* limiter_; |
| |
| public: |
| // base[0,length-1] contains the mmapped contents of the file. |
| PosixMmapReadableFile(const std::string& fname, void* base, size_t length, |
| MmapLimiter* limiter) |
| : filename_(fname), mmapped_region_(base), length_(length), |
| limiter_(limiter) { |
| } |
| |
| virtual ~PosixMmapReadableFile() { |
| munmap(mmapped_region_, length_); |
| limiter_->Release(); |
| } |
| |
| virtual Status Read(uint64_t offset, size_t n, Slice* result, |
| char* scratch) const { |
| Status s; |
| if (offset + n > length_) { |
| *result = Slice(); |
| s = IOError(filename_, EINVAL); |
| } else { |
| *result = Slice(reinterpret_cast<char*>(mmapped_region_) + offset, n); |
| } |
| return s; |
| } |
| }; |
| |
| class PosixWritableFile : public WritableFile { |
| private: |
| std::string filename_; |
| FILE* file_; |
| |
| public: |
| PosixWritableFile(const std::string& fname, FILE* f) |
| : filename_(fname), file_(f) { } |
| |
| ~PosixWritableFile() { |
| if (file_ != NULL) { |
| // Ignoring any potential errors |
| fclose(file_); |
| } |
| } |
| |
| virtual Status Append(const Slice& data) { |
| size_t r = fwrite_unlocked(data.data(), 1, data.size(), file_); |
| if (r != data.size()) { |
| return IOError(filename_, errno); |
| } |
| return Status::OK(); |
| } |
| |
| virtual Status Close() { |
| Status result; |
| if (fclose(file_) != 0) { |
| result = IOError(filename_, errno); |
| } |
| file_ = NULL; |
| return result; |
| } |
| |
| virtual Status Flush() { |
| if (fflush_unlocked(file_) != 0) { |
| return IOError(filename_, errno); |
| } |
| return Status::OK(); |
| } |
| |
| Status SyncDirIfManifest() { |
| const char* f = filename_.c_str(); |
| const char* sep = strrchr(f, '/'); |
| Slice basename; |
| std::string dir; |
| if (sep == NULL) { |
| dir = "."; |
| basename = f; |
| } else { |
| dir = std::string(f, sep - f); |
| basename = sep + 1; |
| } |
| Status s; |
| if (basename.starts_with("MANIFEST")) { |
| int fd = open(dir.c_str(), O_RDONLY); |
| if (fd < 0) { |
| s = IOError(dir, errno); |
| } else { |
| if (fsync(fd) < 0) { |
| s = IOError(dir, errno); |
| } |
| close(fd); |
| } |
| } |
| return s; |
| } |
| |
| virtual Status Sync() { |
| // Ensure new files referred to by the manifest are in the filesystem. |
| Status s = SyncDirIfManifest(); |
| if (!s.ok()) { |
| return s; |
| } |
| if (fflush_unlocked(file_) != 0 || |
| fdatasync(fileno(file_)) != 0) { |
| s = Status::IOError(filename_, strerror(errno)); |
| } |
| return s; |
| } |
| }; |
| |
| static int LockOrUnlock(int fd, bool lock) { |
| errno = 0; |
| struct flock f; |
| memset(&f, 0, sizeof(f)); |
| f.l_type = (lock ? F_WRLCK : F_UNLCK); |
| f.l_whence = SEEK_SET; |
| f.l_start = 0; |
| f.l_len = 0; // Lock/unlock entire file |
| return fcntl(fd, F_SETLK, &f); |
| } |
| |
| class PosixFileLock : public FileLock { |
| public: |
| int fd_; |
| std::string name_; |
| }; |
| |
| // Set of locked files. We keep a separate set instead of just |
| // relying on fcntrl(F_SETLK) since fcntl(F_SETLK) does not provide |
| // any protection against multiple uses from the same process. |
| class PosixLockTable { |
| private: |
| port::Mutex mu_; |
| std::set<std::string> locked_files_; |
| public: |
| bool Insert(const std::string& fname) { |
| MutexLock l(&mu_); |
| return locked_files_.insert(fname).second; |
| } |
| void Remove(const std::string& fname) { |
| MutexLock l(&mu_); |
| locked_files_.erase(fname); |
| } |
| }; |
| |
| class PosixEnv : public Env { |
| public: |
| PosixEnv(); |
| virtual ~PosixEnv() { |
| char msg[] = "Destroying Env::Default()\n"; |
| fwrite(msg, 1, sizeof(msg), stderr); |
| abort(); |
| } |
| |
| virtual Status NewSequentialFile(const std::string& fname, |
| SequentialFile** result) { |
| FILE* f = fopen(fname.c_str(), "r"); |
| if (f == NULL) { |
| *result = NULL; |
| return IOError(fname, errno); |
| } else { |
| *result = new PosixSequentialFile(fname, f); |
| return Status::OK(); |
| } |
| } |
| |
| virtual Status NewRandomAccessFile(const std::string& fname, |
| RandomAccessFile** result) { |
| *result = NULL; |
| Status s; |
| int fd = open(fname.c_str(), O_RDONLY); |
| if (fd < 0) { |
| s = IOError(fname, errno); |
| } else if (mmap_limit_.Acquire()) { |
| uint64_t size; |
| s = GetFileSize(fname, &size); |
| if (s.ok()) { |
| void* base = mmap(NULL, size, PROT_READ, MAP_SHARED, fd, 0); |
| if (base != MAP_FAILED) { |
| *result = new PosixMmapReadableFile(fname, base, size, &mmap_limit_); |
| } else { |
| s = IOError(fname, errno); |
| } |
| } |
| close(fd); |
| if (!s.ok()) { |
| mmap_limit_.Release(); |
| } |
| } else { |
| *result = new PosixRandomAccessFile(fname, fd); |
| } |
| return s; |
| } |
| |
| virtual Status NewWritableFile(const std::string& fname, |
| WritableFile** result) { |
| Status s; |
| FILE* f = fopen(fname.c_str(), "w"); |
| if (f == NULL) { |
| *result = NULL; |
| s = IOError(fname, errno); |
| } else { |
| *result = new PosixWritableFile(fname, f); |
| } |
| return s; |
| } |
| |
| virtual bool FileExists(const std::string& fname) { |
| return access(fname.c_str(), F_OK) == 0; |
| } |
| |
| virtual Status GetChildren(const std::string& dir, |
| std::vector<std::string>* result) { |
| result->clear(); |
| DIR* d = opendir(dir.c_str()); |
| if (d == NULL) { |
| return IOError(dir, errno); |
| } |
| struct dirent* entry; |
| while ((entry = readdir(d)) != NULL) { |
| result->push_back(entry->d_name); |
| } |
| closedir(d); |
| return Status::OK(); |
| } |
| |
| virtual Status DeleteFile(const std::string& fname) { |
| Status result; |
| if (unlink(fname.c_str()) != 0) { |
| result = IOError(fname, errno); |
| } |
| return result; |
| } |
| |
| virtual Status CreateDir(const std::string& name) { |
| Status result; |
| if (mkdir(name.c_str(), 0755) != 0) { |
| result = IOError(name, errno); |
| } |
| return result; |
| } |
| |
| virtual Status DeleteDir(const std::string& name) { |
| Status result; |
| if (rmdir(name.c_str()) != 0) { |
| result = IOError(name, errno); |
| } |
| return result; |
| } |
| |
| virtual Status GetFileSize(const std::string& fname, uint64_t* size) { |
| Status s; |
| struct stat sbuf; |
| if (stat(fname.c_str(), &sbuf) != 0) { |
| *size = 0; |
| s = IOError(fname, errno); |
| } else { |
| *size = sbuf.st_size; |
| } |
| return s; |
| } |
| |
| virtual Status RenameFile(const std::string& src, const std::string& target) { |
| Status result; |
| if (rename(src.c_str(), target.c_str()) != 0) { |
| result = IOError(src, errno); |
| } |
| return result; |
| } |
| |
| virtual Status LockFile(const std::string& fname, FileLock** lock) { |
| *lock = NULL; |
| Status result; |
| int fd = open(fname.c_str(), O_RDWR | O_CREAT, 0644); |
| if (fd < 0) { |
| result = IOError(fname, errno); |
| } else if (!locks_.Insert(fname)) { |
| close(fd); |
| result = Status::IOError("lock " + fname, "already held by process"); |
| } else if (LockOrUnlock(fd, true) == -1) { |
| result = IOError("lock " + fname, errno); |
| close(fd); |
| locks_.Remove(fname); |
| } else { |
| PosixFileLock* my_lock = new PosixFileLock; |
| my_lock->fd_ = fd; |
| my_lock->name_ = fname; |
| *lock = my_lock; |
| } |
| return result; |
| } |
| |
| virtual Status UnlockFile(FileLock* lock) { |
| PosixFileLock* my_lock = reinterpret_cast<PosixFileLock*>(lock); |
| Status result; |
| if (LockOrUnlock(my_lock->fd_, false) == -1) { |
| result = IOError("unlock", errno); |
| } |
| locks_.Remove(my_lock->name_); |
| close(my_lock->fd_); |
| delete my_lock; |
| return result; |
| } |
| |
| virtual void Schedule(void (*function)(void*), void* arg); |
| |
| virtual void StartThread(void (*function)(void* arg), void* arg); |
| |
| virtual Status GetTestDirectory(std::string* result) { |
| const char* env = getenv("TEST_TMPDIR"); |
| if (env && env[0] != '\0') { |
| *result = env; |
| } else { |
| char buf[100]; |
| snprintf(buf, sizeof(buf), "/tmp/leveldbtest-%d", int(geteuid())); |
| *result = buf; |
| } |
| // Directory may already exist |
| CreateDir(*result); |
| return Status::OK(); |
| } |
| |
| static uint64_t gettid() { |
| pthread_t tid = pthread_self(); |
| uint64_t thread_id = 0; |
| memcpy(&thread_id, &tid, std::min(sizeof(thread_id), sizeof(tid))); |
| return thread_id; |
| } |
| |
| virtual Status NewLogger(const std::string& fname, Logger** result) { |
| FILE* f = fopen(fname.c_str(), "w"); |
| if (f == NULL) { |
| *result = NULL; |
| return IOError(fname, errno); |
| } else { |
| *result = new PosixLogger(f, &PosixEnv::gettid); |
| return Status::OK(); |
| } |
| } |
| |
| virtual uint64_t NowMicros() { |
| struct timeval tv; |
| gettimeofday(&tv, NULL); |
| return static_cast<uint64_t>(tv.tv_sec) * 1000000 + tv.tv_usec; |
| } |
| |
| virtual void SleepForMicroseconds(int micros) { |
| usleep(micros); |
| } |
| |
| private: |
| void PthreadCall(const char* label, int result) { |
| if (result != 0) { |
| fprintf(stderr, "pthread %s: %s\n", label, strerror(result)); |
| abort(); |
| } |
| } |
| |
| // BGThread() is the body of the background thread |
| void BGThread(); |
| static void* BGThreadWrapper(void* arg) { |
| reinterpret_cast<PosixEnv*>(arg)->BGThread(); |
| return NULL; |
| } |
| |
| pthread_mutex_t mu_; |
| pthread_cond_t bgsignal_; |
| pthread_t bgthread_; |
| bool started_bgthread_; |
| |
| // Entry per Schedule() call |
| struct BGItem { void* arg; void (*function)(void*); }; |
| typedef std::deque<BGItem> BGQueue; |
| BGQueue queue_; |
| |
| PosixLockTable locks_; |
| MmapLimiter mmap_limit_; |
| }; |
| |
| PosixEnv::PosixEnv() : started_bgthread_(false) { |
| PthreadCall("mutex_init", pthread_mutex_init(&mu_, NULL)); |
| PthreadCall("cvar_init", pthread_cond_init(&bgsignal_, NULL)); |
| } |
| |
| void PosixEnv::Schedule(void (*function)(void*), void* arg) { |
| PthreadCall("lock", pthread_mutex_lock(&mu_)); |
| |
| // Start background thread if necessary |
| if (!started_bgthread_) { |
| started_bgthread_ = true; |
| PthreadCall( |
| "create thread", |
| pthread_create(&bgthread_, NULL, &PosixEnv::BGThreadWrapper, this)); |
| } |
| |
| // If the queue is currently empty, the background thread may currently be |
| // waiting. |
| if (queue_.empty()) { |
| PthreadCall("signal", pthread_cond_signal(&bgsignal_)); |
| } |
| |
| // Add to priority queue |
| queue_.push_back(BGItem()); |
| queue_.back().function = function; |
| queue_.back().arg = arg; |
| |
| PthreadCall("unlock", pthread_mutex_unlock(&mu_)); |
| } |
| |
| void PosixEnv::BGThread() { |
| while (true) { |
| // Wait until there is an item that is ready to run |
| PthreadCall("lock", pthread_mutex_lock(&mu_)); |
| while (queue_.empty()) { |
| PthreadCall("wait", pthread_cond_wait(&bgsignal_, &mu_)); |
| } |
| |
| void (*function)(void*) = queue_.front().function; |
| void* arg = queue_.front().arg; |
| queue_.pop_front(); |
| |
| PthreadCall("unlock", pthread_mutex_unlock(&mu_)); |
| (*function)(arg); |
| } |
| } |
| |
| namespace { |
| struct StartThreadState { |
| void (*user_function)(void*); |
| void* arg; |
| }; |
| } |
| static void* StartThreadWrapper(void* arg) { |
| StartThreadState* state = reinterpret_cast<StartThreadState*>(arg); |
| state->user_function(state->arg); |
| delete state; |
| return NULL; |
| } |
| |
| void PosixEnv::StartThread(void (*function)(void* arg), void* arg) { |
| pthread_t t; |
| StartThreadState* state = new StartThreadState; |
| state->user_function = function; |
| state->arg = arg; |
| PthreadCall("start thread", |
| pthread_create(&t, NULL, &StartThreadWrapper, state)); |
| } |
| |
| } // namespace |
| |
| static pthread_once_t once = PTHREAD_ONCE_INIT; |
| static Env* default_env; |
| static void InitDefaultEnv() { default_env = new PosixEnv; } |
| |
| Env* Env::Default() { |
| pthread_once(&once, InitDefaultEnv); |
| return default_env; |
| } |
| |
| } // namespace leveldb |