| // 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 <deque> |
| #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> |
| #if defined(LEVELDB_PLATFORM_ANDROID) |
| #include <sys/stat.h> |
| #endif |
| #include "leveldb/env.h" |
| #include "leveldb/slice.h" |
| #include "port/port.h" |
| #include "util/logging.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(); |
| } |
| }; |
| |
| 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; |
| } |
| }; |
| |
| // We preallocate up to an extra megabyte and use memcpy to append new |
| // data to the file. This is safe since we either properly close the |
| // file before reading from it, or for log files, the reading code |
| // knows enough to skip zero suffixes. |
| class PosixMmapFile : public WritableFile { |
| private: |
| std::string filename_; |
| int fd_; |
| size_t page_size_; |
| size_t map_size_; // How much extra memory to map at a time |
| char* base_; // The mapped region |
| char* limit_; // Limit of the mapped region |
| char* dst_; // Where to write next (in range [base_,limit_]) |
| char* last_sync_; // Where have we synced up to |
| uint64_t file_offset_; // Offset of base_ in file |
| |
| // Have we done an munmap of unsynced data? |
| bool pending_sync_; |
| |
| // Roundup x to a multiple of y |
| static size_t Roundup(size_t x, size_t y) { |
| return ((x + y - 1) / y) * y; |
| } |
| |
| size_t TruncateToPageBoundary(size_t s) { |
| s -= (s & (page_size_ - 1)); |
| assert((s % page_size_) == 0); |
| return s; |
| } |
| |
| bool UnmapCurrentRegion() { |
| bool result = true; |
| if (base_ != NULL) { |
| if (last_sync_ < limit_) { |
| // Defer syncing this data until next Sync() call, if any |
| pending_sync_ = true; |
| } |
| if (munmap(base_, limit_ - base_) != 0) { |
| result = false; |
| } |
| file_offset_ += limit_ - base_; |
| base_ = NULL; |
| limit_ = NULL; |
| last_sync_ = NULL; |
| dst_ = NULL; |
| |
| // Increase the amount we map the next time, but capped at 1MB |
| if (map_size_ < (1<<20)) { |
| map_size_ *= 2; |
| } |
| } |
| return result; |
| } |
| |
| bool MapNewRegion() { |
| assert(base_ == NULL); |
| if (ftruncate(fd_, file_offset_ + map_size_) < 0) { |
| return false; |
| } |
| void* ptr = mmap(NULL, map_size_, PROT_READ | PROT_WRITE, MAP_SHARED, |
| fd_, file_offset_); |
| if (ptr == MAP_FAILED) { |
| return false; |
| } |
| base_ = reinterpret_cast<char*>(ptr); |
| limit_ = base_ + map_size_; |
| dst_ = base_; |
| last_sync_ = base_; |
| return true; |
| } |
| |
| public: |
| PosixMmapFile(const std::string& fname, int fd, size_t page_size) |
| : filename_(fname), |
| fd_(fd), |
| page_size_(page_size), |
| map_size_(Roundup(65536, page_size)), |
| base_(NULL), |
| limit_(NULL), |
| dst_(NULL), |
| last_sync_(NULL), |
| file_offset_(0), |
| pending_sync_(false) { |
| assert((page_size & (page_size - 1)) == 0); |
| } |
| |
| |
| ~PosixMmapFile() { |
| if (fd_ >= 0) { |
| PosixMmapFile::Close(); |
| } |
| } |
| |
| virtual Status Append(const Slice& data) { |
| const char* src = data.data(); |
| size_t left = data.size(); |
| while (left > 0) { |
| assert(base_ <= dst_); |
| assert(dst_ <= limit_); |
| size_t avail = limit_ - dst_; |
| if (avail == 0) { |
| if (!UnmapCurrentRegion() || |
| !MapNewRegion()) { |
| return IOError(filename_, errno); |
| } |
| } |
| |
| size_t n = (left <= avail) ? left : avail; |
| memcpy(dst_, src, n); |
| dst_ += n; |
| src += n; |
| left -= n; |
| } |
| return Status::OK(); |
| } |
| |
| virtual Status Close() { |
| Status s; |
| size_t unused = limit_ - dst_; |
| if (!UnmapCurrentRegion()) { |
| s = IOError(filename_, errno); |
| } else if (unused > 0) { |
| // Trim the extra space at the end of the file |
| if (ftruncate(fd_, file_offset_ - unused) < 0) { |
| s = IOError(filename_, errno); |
| } |
| } |
| |
| if (close(fd_) < 0) { |
| if (s.ok()) { |
| s = IOError(filename_, errno); |
| } |
| } |
| |
| fd_ = -1; |
| base_ = NULL; |
| limit_ = NULL; |
| return s; |
| } |
| |
| virtual Status Flush() { |
| return Status::OK(); |
| } |
| |
| virtual Status Sync() { |
| Status s; |
| |
| if (pending_sync_) { |
| // Some unmapped data was not synced |
| pending_sync_ = false; |
| if (fdatasync(fd_) < 0) { |
| s = IOError(filename_, errno); |
| } |
| } |
| |
| if (dst_ > last_sync_) { |
| // Find the beginnings of the pages that contain the first and last |
| // bytes to be synced. |
| size_t p1 = TruncateToPageBoundary(last_sync_ - base_); |
| size_t p2 = TruncateToPageBoundary(dst_ - base_ - 1); |
| last_sync_ = dst_; |
| if (msync(base_ + p1, p2 - p1 + page_size_, MS_SYNC) < 0) { |
| s = IOError(filename_, 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_; |
| }; |
| |
| class PosixEnv : public Env { |
| public: |
| PosixEnv(); |
| virtual ~PosixEnv() { |
| fprintf(stderr, "Destroying Env::Default()\n"); |
| exit(1); |
| } |
| |
| 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) { |
| int fd = open(fname.c_str(), O_RDONLY); |
| if (fd < 0) { |
| *result = NULL; |
| return IOError(fname, errno); |
| } |
| *result = new PosixRandomAccessFile(fname, fd); |
| return Status::OK(); |
| } |
| |
| virtual Status NewWritableFile(const std::string& fname, |
| WritableFile** result) { |
| Status s; |
| const int fd = open(fname.c_str(), O_CREAT | O_RDWR | O_TRUNC, 0644); |
| if (fd < 0) { |
| *result = NULL; |
| s = IOError(fname, errno); |
| } else { |
| *result = new PosixMmapFile(fname, fd, page_size_); |
| } |
| 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 (LockOrUnlock(fd, true) == -1) { |
| result = IOError("lock " + fname, errno); |
| close(fd); |
| } else { |
| PosixFileLock* my_lock = new PosixFileLock; |
| my_lock->fd_ = fd; |
| *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); |
| } |
| 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)); |
| exit(1); |
| } |
| } |
| |
| // BGThread() is the body of the background thread |
| void BGThread(); |
| static void* BGThreadWrapper(void* arg) { |
| reinterpret_cast<PosixEnv*>(arg)->BGThread(); |
| return NULL; |
| } |
| |
| size_t page_size_; |
| 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_; |
| }; |
| |
| PosixEnv::PosixEnv() : page_size_(getpagesize()), |
| 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 |