1 /*
   2  * Copyright (c) 2016, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #include "precompiled.hpp"
  26 #include "logging/log.hpp"
  27 #include "logging/logStream.hpp"
  28 
  29 LogStream::LineBuffer::LineBuffer()
  30  : _buf(_smallbuf), _cap(sizeof(_smallbuf)), _pos(0)
  31 {
  32   _buf[0] = '\0';
  33 }
  34 
  35 LogStream::LineBuffer::~LineBuffer() {
  36   assert(_pos == 0, "still outstanding bytes in the line buffer");
  37   if (_buf != _smallbuf) {
  38     os::free(_buf);
  39   }
  40 }
  41 
  42 // try_ensure_cap tries to enlarge the capacity of the internal buffer
  43 // to the given atleast value. May fail if either OOM happens or atleast
  44 // is larger than a reasonable max of 1 M. Caller must not assume
  45 // capacity without checking.
  46 void LogStream::LineBuffer::try_ensure_cap(size_t atleast) {
  47   assert(_cap >= sizeof(_smallbuf), "sanity");
  48   if (_cap < atleast) {
  49     // Cap out at a reasonable max to prevent runaway leaks.
  50     const size_t reasonable_max = 1 * M;
  51     assert(_cap <= reasonable_max, "sanity");
  52     if (_cap == reasonable_max) {
  53       return;
  54     }
  55 
  56     const size_t additional_expansion = 256;
  57     size_t newcap = align_up(atleast + additional_expansion, additional_expansion);
  58     if (newcap > reasonable_max) {
  59       log_info(logging)("Suspiciously long log line: \"%.100s%s",
  60               _buf, (_pos >= 100 ? "..." : ""));
  61       newcap = reasonable_max;
  62     }
  63 
  64     char* const newbuf = (char*) os::malloc(newcap, mtLogging);
  65     if (newbuf == NULL) { // OOM. Leave object unchanged.
  66       return;
  67     }
  68     if (_pos > 0) { // preserve old content
  69       memcpy(newbuf, _buf, _pos + 1); // ..including trailing zero
  70     }
  71     if (_buf != _smallbuf) {
  72       os::free(_buf);
  73     }
  74     _buf = newbuf;
  75     _cap = newcap;
  76   }
  77   assert(_cap >= atleast, "sanity");
  78 }
  79 
  80 void LogStream::LineBuffer::append(const char* s, size_t len) {
  81   assert(_buf[_pos] == '\0', "sanity");
  82   assert(_pos < _cap, "sanity");
  83   const size_t minimum_capacity_needed = _pos + len + 1;
  84   try_ensure_cap(minimum_capacity_needed);
  85   // try_ensure_cap may not have enlarged the capacity to the full requested
  86   // extend or may have not worked at all. In that case, just gracefully work
  87   // with what we have already; just truncate if necessary.
  88   if (_cap < minimum_capacity_needed) {
  89     len = _cap - _pos - 1;
  90     if (len == 0) {
  91       return;
  92     }
  93   }
  94   memcpy(_buf + _pos, s, len);
  95   _pos += len;
  96   _buf[_pos] = '\0';
  97 }
  98 
  99 void LogStream::LineBuffer::reset() {
 100   _pos = 0;
 101   _buf[_pos] = '\0';
 102 }
 103 
 104 void LogStream::write(const char* s, size_t len) {
 105   if (len > 0 && s[len - 1] == '\n') {
 106     _current_line.append(s, len - 1); // omit the newline.
 107     _log_handle.print("%s", _current_line.buffer());
 108     _current_line.reset();
 109   } else {
 110     _current_line.append(s, len);
 111   }
 112   update_position(s, len);
 113 }
 114