livestatus/src/OffsetStringMacroColumn.cc

   1 // +------------------------------------------------------------------+
   2 // |             ____ _               _        __  __ _  __           |
   3 // |            / ___| |__   ___  ___| | __   |  \/  | |/ /           |
   4 // |           | |   | '_ \ / _ \/ __| |/ /   | |\/| | ' /            |
   5 // |           | |___| | | |  __/ (__|   <    | |  | | . \            |
   6 // |            \____|_| |_|\___|\___|_|\_\___|_|  |_|_|\_\           |
   7 // |                                                                  |
   8 // | Copyright Mathias Kettner 2014             mk@mathias-kettner.de |
   9 // +------------------------------------------------------------------+
  10 //
  11 // This file is part of Check_MK.
  12 // The official homepage is at http://mathias-kettner.de/check_mk.
  13 //
  14 // check_mk is free software;  you can redistribute it and/or modify it
  15 // under the  terms of the  GNU General Public License  as published by
  16 // the Free Software Foundation in version 2.  check_mk is  distributed
  17 // in the hope that it will be useful, but WITHOUT ANY WARRANTY;  with-
  18 // out even the implied warranty of  MERCHANTABILITY  or  FITNESS FOR A
  19 // PARTICULAR PURPOSE. See the  GNU General Public License for more de-
  20 // tails. You should have  received  a copy of the  GNU  General Public
  21 // License along with GNU Make; see the file  COPYING.  If  not,  write
  22 // to the Free Software Foundation, Inc., 51 Franklin St,  Fifth Floor,
  23 // Boston, MA 02110-1301 USA.
  24
  25 #include "OffsetStringMacroColumn.h"
  26 #include <cstdlib>
  27 #include <type_traits>
  28 #include <utility>
  29 #include "Column.h"
  30 #include "MonitoringCore.h"
  31 #include "RegExp.h"
  32 #include "Row.h"
  33 #include "StringUtils.h"
  34
  35 std::optional<std::string> MacroExpander::from_ptr(const char *str) {
  36     return str == nullptr ? std::nullopt : std::make_optional(str);
  37 }
  38
  39 CompoundMacroExpander::CompoundMacroExpander(
  40     std::unique_ptr<MacroExpander> first, std::unique_ptr<MacroExpander> second)
  41     : _first(std::move(first)), _second(std::move(second)) {}
  42
  43 std::optional<std::string> CompoundMacroExpander::expand(
  44     const std::string &str) {
  45     if (auto e = _first->expand(str)) {
  46         return e;
  47     }
  48     return _second->expand(str);
  49 }
  50
  51 std::optional<std::string> UserMacroExpander::expand(const std::string &str) {
  52     if (mk::starts_with(str, "USER")) {
  53         int n = atoi(str.substr(4).c_str());
  54         if (1 <= n && n <= MAX_USER_MACROS) {
  55             extern char *macro_user[MAX_USER_MACROS];
  56             return from_ptr(macro_user[n - 1]);
  57         }
  58     }
  59     return {};
  60 }
  61
  62 CustomVariableExpander::CustomVariableExpander(std::string prefix,
  63                                                const customvariablesmember *cvm,
  64                                                const MonitoringCore *mc)
  65     : _prefix(std::move(prefix)), _mc(mc), _cvm(cvm) {}
  66
  67 std::optional<std::string> CustomVariableExpander::expand(
  68     const std::string &str) {
  69     if (!mk::starts_with(str, _prefix)) {
  70         return {};
  71     }
  72
  73     RegExp regExp(str.substr(_prefix.size()), RegExp::Case::ignore,
  74                   RegExp::Syntax::literal);
  75     for (const auto &[name, value] :
  76          _mc->customAttributes(&_cvm, AttributeKind::custom_variables)) {
  77         if (regExp.match(name)) {
  78             return value;
  79         }
  80     }
  81     return {};
  82 }
  83
  84 namespace {
  85 std::string expandMacros(const std::string &raw,
  86                          std::unique_ptr<MacroExpander> expander) {
  87     std::string result;
  88     size_t pos = 0;
  89     while (pos < raw.size()) {
  90         auto start = raw.find('$', pos);
  91         if (start == std::string::npos) {
  92             result += raw.substr(pos);
  93             break;
  94         }
  95         auto end = raw.find('$', start + 1);
  96         if (end == std::string::npos) {
  97             result += raw.substr(pos);
  98             break;
  99         }
 100         auto macroname = raw.substr(start + 1, end - (start + 1));
 101         if (auto replacement = expander->expand(macroname)) {
 102             result += raw.substr(pos, start - pos) + *replacement;
 103         } else {
 104             result += raw.substr(pos, end + 1 - pos);
 105         }
 106         pos = end + 1;
 107     }
 108     return result;
 109 }
 110 }  // namespace
 111
 112 std::string OffsetStringMacroColumn::getValue(Row row) const {
 113     // TODO(sp): Use _mc!
 114     (void)_mc;
 115     if (auto p = columnData<void>(row)) {
 116         auto s = offset_cast<const char *>(p, _string_offset);
 117         return *s == nullptr ? "" : expandMacros(*s, getMacroExpander(row));
 118     }
 119     return "";
 120 }