/*

 * Copyright (c) 2015, 2017, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 *

 */

#include "precompiled.hpp"

#include "jvm.h"

#include "logging/log.hpp"

#include "logging/logConfiguration.hpp"

#include "logging/logFileOutput.hpp"

#include "memory/allocation.inline.hpp"

#include "runtime/arguments.hpp"

#include "runtime/os.inline.hpp"

#include "utilities/globalDefinitions.hpp"

#include "utilities/defaultStream.hpp"

const char* const LogFileOutput::Prefix = "file=";

const char* const LogFileOutput::FileOpenMode = "a";

const char* const LogFileOutput::PidFilenamePlaceholder = "%p";

const char* const LogFileOutput::TimestampFilenamePlaceholder = "%t";

const char* const LogFileOutput::TimestampFormat = "%Y-%m-%d_%H-%M-%S";

const char* const LogFileOutput::FileSizeOptionKey = "filesize";

const char* const LogFileOutput::FileCountOptionKey = "filecount";

char        LogFileOutput::_pid_str[PidBufferSize];

char        LogFileOutput::_vm_start_time_str[StartTimeBufferSize];

LogFileOutput::LogFileOutput(const char* name)

    : LogFileStreamOutput(NULL), _name(os::strdup_check_oom(name, mtLogging)),

      _file_name(NULL), _archive_name(NULL), _archive_name_len(0),

      _rotate_size(DefaultFileSize), _file_count(DefaultFileCount),

      _current_size(0), _current_file(0), _rotation_semaphore(1) {

  assert(strstr(name, Prefix) == name, "invalid output name '%s': missing prefix: %s", name, Prefix);

  _file_name = make_file_name(name + strlen(Prefix), _pid_str, _vm_start_time_str);

}

void LogFileOutput::set_file_name_parameters(jlong vm_start_time) {

  int res = jio_snprintf(_pid_str, sizeof(_pid_str), "%d", os::current_process_id());

  assert(res > 0, "PID buffer too small");

  struct tm local_time;

  time_t utc_time = vm_start_time / 1000;

  os::localtime_pd(&utc_time, &local_time);

  res = (int)strftime(_vm_start_time_str, sizeof(_vm_start_time_str), TimestampFormat, &local_time);

  assert(res > 0, "VM start time buffer too small.");

}

LogFileOutput::~LogFileOutput() {

  if (_stream != NULL) {

    if (fclose(_stream) != 0) {

      jio_fprintf(defaultStream::error_stream(), "Could not close log file '%s' (%s).\n",

                  _file_name, os::strerror(errno));

    }

  }

  os::free(_archive_name);

  os::free(_file_name);

  os::free(const_cast<char*>(_name));

}

static size_t parse_value(const char* value_str) {

  char* end;

  unsigned long long value = strtoull(value_str, &end, 10);

  if (!isdigit(*value_str) || end != value_str + strlen(value_str) || value >= SIZE_MAX) {

    return SIZE_MAX;

  }

  return value;

}

static bool file_exists(const char* filename) {

  struct stat dummy_stat;

  return os::stat(filename, &dummy_stat) == 0;

}

static uint number_of_digits(uint number) {

  return number < 10 ? 1 : (number < 100 ? 2 : 3);

}

static bool is_regular_file(const char* filename) {

  struct stat st;

  int ret = os::stat(filename, &st);

  if (ret != 0) {

    return false;

  }

  return (st.st_mode & S_IFMT) == S_IFREG;

}

// Try to find the next number that should be used for file rotation.

// Return UINT_MAX on error.

static uint next_file_number(const char* filename,

                             uint number_of_digits,

                             uint filecount,

                             outputStream* errstream) {

  bool found = false;

  uint next_num = 0;

  // len is filename + dot + digits + null char

  size_t len = strlen(filename) + number_of_digits + 2;

  char* archive_name = NEW_C_HEAP_ARRAY(char, len, mtLogging);

  char* oldest_name = NEW_C_HEAP_ARRAY(char, len, mtLogging);

  for (uint i = 0; i < filecount; i++) {

    int ret = jio_snprintf(archive_name, len, "%s.%0*u",

                           filename, number_of_digits, i);

    assert(ret > 0 && static_cast<size_t>(ret) == len - 1,

           "incorrect buffer length calculation");

    if (file_exists(archive_name) && !is_regular_file(archive_name)) {

      // We've encountered something that's not a regular file among the

      // possible file rotation targets. Fail immediately to prevent

      // problems later.

      errstream->print_cr("Possible rotation target file '%s' already exists "

                          "but is not a regular file.", archive_name);

      next_num = UINT_MAX;

      break;

    }

    // Stop looking if we find an unused file name

    if (!file_exists(archive_name)) {

      next_num = i;

      found = true;

      break;

    }

    // Keep track of oldest existing log file

    if (!found

        || os::compare_file_modified_times(oldest_name, archive_name) > 0) {

      strcpy(oldest_name, archive_name);

      next_num = i;

      found = true;

    }

  }

  FREE_C_HEAP_ARRAY(char, oldest_name);

  FREE_C_HEAP_ARRAY(char, archive_name);

  return next_num;

}

bool LogFileOutput::parse_options(const char* options, outputStream* errstream) {

  if (options == NULL || strlen(options) == 0) {

    return true;

  }

  bool success = true;

  char* opts = os::strdup_check_oom(options, mtLogging);

  char* comma_pos;

  char* pos = opts;

  do {

    comma_pos = strchr(pos, ',');

    if (comma_pos != NULL) {

      *comma_pos = '\0';

    }

    char* equals_pos = strchr(pos, '=');

    if (equals_pos == NULL) {

      success = false;

      break;

    }

    char* key = pos;

    char* value_str = equals_pos + 1;

    *equals_pos = '\0';

    if (strcmp(FileCountOptionKey, key) == 0) {

      size_t value = parse_value(value_str);

      if (value > MaxRotationFileCount) {

        errstream->print_cr("Invalid option: %s must be in range [0, %u]",

                            FileCountOptionKey,

                            MaxRotationFileCount);

        success = false;

        break;

      }

      _file_count = static_cast<uint>(value);

    } else if (strcmp(FileSizeOptionKey, key) == 0) {

      julong value;

      success = Arguments::atojulong(value_str, &value);

      if (!success || (value > SIZE_MAX)) {

        errstream->print_cr("Invalid option: %s must be in range [0, "

                            SIZE_FORMAT "]", FileSizeOptionKey, (size_t)SIZE_MAX);

        success = false;

        break;

      }

      _rotate_size = static_cast<size_t>(value);

    } else {

      errstream->print_cr("Invalid option '%s' for log file output.", key);

      success = false;

      break;

    }

    pos = comma_pos + 1;

  } while (comma_pos != NULL);

  os::free(opts);

  return success;

}

bool LogFileOutput::initialize(const char* options, outputStream* errstream) {

  if (!parse_options(options, errstream)) {

    return false;

  }

  if (_file_count > 0) {

    // compute digits with filecount - 1 since numbers will start from 0

    _file_count_max_digits = number_of_digits(_file_count - 1);

    _archive_name_len = 2 + strlen(_file_name) + _file_count_max_digits;

    _archive_name = NEW_C_HEAP_ARRAY(char, _archive_name_len, mtLogging);

  }

  log_trace(logging)("Initializing logging to file '%s' (filecount: %u"

                     ", filesize: " SIZE_FORMAT " KiB).",

                     _file_name, _file_count, _rotate_size / K);

  if (_file_count > 0 && file_exists(_file_name)) {

    if (!is_regular_file(_file_name)) {

      errstream->print_cr("Unable to log to file %s with log file rotation: "

                          "%s is not a regular file",

                          _file_name, _file_name);

      return false;

    }

    _current_file = next_file_number(_file_name,

                                     _file_count_max_digits,

                                     _file_count,

                                     errstream);

    if (_current_file == UINT_MAX) {

      return false;

    }

    log_trace(logging)("Existing log file found, saving it as '%s.%0*u'",

                       _file_name, _file_count_max_digits, _current_file);

    archive();

    increment_file_count();

  }

  _stream = fopen(_file_name, FileOpenMode);

  if (_stream == NULL) {

    errstream->print_cr("Error opening log file '%s': %s",

                        _file_name, strerror(errno));

    return false;

  }

  if (_file_count == 0 && is_regular_file(_file_name)) {

    log_trace(logging)("Truncating log file");

    os::ftruncate(os::get_fileno(_stream), 0);

  }

  return true;

}

int LogFileOutput::write(const LogDecorations& decorations, const char* msg) {

  if (_stream == NULL) {

    // An error has occurred with this output, avoid writing to it.

    return 0;

  }

  _rotation_semaphore.wait();

  int written = LogFileStreamOutput::write(decorations, msg);

  _current_size += written;

  if (should_rotate()) {

    rotate();

  }

  _rotation_semaphore.signal();

  return written;

}

int LogFileOutput::write(LogMessageBuffer::Iterator msg_iterator) {

  if (_stream == NULL) {

    // An error has occurred with this output, avoid writing to it.

    return 0;

  }

  _rotation_semaphore.wait();

  int written = LogFileStreamOutput::write(msg_iterator);

  _current_size += written;

  if (should_rotate()) {

    rotate();

  }

  _rotation_semaphore.signal();

  return written;

}

void LogFileOutput::archive() {

  assert(_archive_name != NULL && _archive_name_len > 0, "Rotation must be configured before using this function.");

  int ret = jio_snprintf(_archive_name, _archive_name_len, "%s.%0*u",

                         _file_name, _file_count_max_digits, _current_file);

  assert(ret >= 0, "Buffer should always be large enough");

  // Attempt to remove possibly existing archived log file before we rename.

  // Don't care if it fails, we really only care about the rename that follows.

  remove(_archive_name);

  // Rename the file from ex hotspot.log to hotspot.log.2

  if (rename(_file_name, _archive_name) == -1) {

    jio_fprintf(defaultStream::error_stream(), "Could not rename log file '%s' to '%s' (%s).\n",

                _file_name, _archive_name, os::strerror(errno));

  }

}

void LogFileOutput::force_rotate() {

  if (_file_count == 0) {

    // Rotation not possible

    return;

  }

  _rotation_semaphore.wait();

  rotate();

  _rotation_semaphore.signal();

}

void LogFileOutput::rotate() {

  if (fclose(_stream)) {

    jio_fprintf(defaultStream::error_stream(), "Error closing file '%s' during log rotation (%s).\n",

                _file_name, os::strerror(errno));

  }

  // Archive the current log file

  archive();

  // Open the active log file using the same stream as before

  _stream = fopen(_file_name, FileOpenMode);

  if (_stream == NULL) {

    jio_fprintf(defaultStream::error_stream(), "Could not reopen file '%s' during log rotation (%s).\n",

                _file_name, os::strerror(errno));

    return;

  }

  // Reset accumulated size, increase current file counter, and check for file count wrap-around.

  _current_size = 0;

  increment_file_count();

}

char* LogFileOutput::make_file_name(const char* file_name,

                                    const char* pid_string,

                                    const char* timestamp_string) {

  char* result = NULL;

  // Lets start finding out if we have any %d and/or %t in the name.

  // We will only replace the first occurrence of any placeholder

  const char* pid = strstr(file_name, PidFilenamePlaceholder);

  const char* timestamp = strstr(file_name, TimestampFilenamePlaceholder);

  if (pid == NULL && timestamp == NULL) {

    // We found no place-holders, return the simple filename

    return os::strdup_check_oom(file_name, mtLogging);

  }

  // At least one of the place-holders were found in the file_name

  const char* first = "";

  size_t first_pos = SIZE_MAX;

  size_t first_replace_len = 0;

  const char* second = "";

  size_t second_pos = SIZE_MAX;

  size_t second_replace_len = 0;

  // If we found a %p, then setup our variables accordingly

  if (pid != NULL) {

    if (timestamp == NULL || pid < timestamp) {

      first = pid_string;

      first_pos = pid - file_name;

      first_replace_len = strlen(PidFilenamePlaceholder);

    } else {

      second = pid_string;

      second_pos = pid - file_name;

      second_replace_len = strlen(PidFilenamePlaceholder);

    }

  }

  if (timestamp != NULL) {

    if (pid == NULL || timestamp < pid) {

      first = timestamp_string;

      first_pos = timestamp - file_name;

      first_replace_len = strlen(TimestampFilenamePlaceholder);

    } else {

      second = timestamp_string;

      second_pos = timestamp - file_name;

      second_replace_len = strlen(TimestampFilenamePlaceholder);

    }

  }

  size_t first_len = strlen(first);

  size_t second_len = strlen(second);

  // Allocate the new buffer, size it to hold all we want to put in there +1.

  size_t result_len =  strlen(file_name) + first_len - first_replace_len + second_len - second_replace_len;

  result = NEW_C_HEAP_ARRAY(char, result_len + 1, mtLogging);

  // Assemble the strings

  size_t file_name_pos = 0;

  size_t i = 0;

  while (i < result_len) {

    if (file_name_pos == first_pos) {

      // We are in the range of the first placeholder

      strcpy(result + i, first);

      // Bump output buffer position with length of replacing string

      i += first_len;

      // Bump source buffer position to skip placeholder

      file_name_pos += first_replace_len;

    } else if (file_name_pos == second_pos) {

      // We are in the range of the second placeholder

      strcpy(result + i, second);

      i += second_len;

      file_name_pos += second_replace_len;

    } else {

      // Else, copy char by char of the original file

      result[i] = file_name[file_name_pos++];

      i++;

    }

  }

  // Add terminating char

  result[result_len] = '\0';

  return result;

}

void LogFileOutput::describe(outputStream *out) {

  LogOutput::describe(out);

  out->print(" ");

  out->print("filecount=%u,filesize=" SIZE_FORMAT "%s", _file_count,

             byte_size_in_proper_unit(_rotate_size),

             proper_unit_for_byte_size(_rotate_size));

}