001/*
002 * Logback: the reliable, generic, fast and flexible logging framework.
003 * Copyright (C) 1999-2026, QOS.ch. All rights reserved.
004 *
005 * This program and the accompanying materials are dual-licensed under
006 * either the terms of the Eclipse Public License v2.0 as published by
007 * the Eclipse Foundation
008 *
009 *   or (per the licensee's choosing)
010 *
011 * under the terms of the GNU Lesser General Public License version 2.1
012 * as published by the Free Software Foundation.
013 */
014package ch.qos.logback.core.model.processor.conditional;
015
016import ch.qos.logback.core.util.EnvUtil;
017import ch.qos.logback.core.util.OptionHelper;
018import ch.qos.logback.core.Context;
019import ch.qos.logback.core.CoreConstants;
020import ch.qos.logback.core.joran.conditional.Condition;
021import ch.qos.logback.core.joran.conditional.PropertyEvalScriptBuilder;
022import ch.qos.logback.core.model.Model;
023import ch.qos.logback.core.model.conditional.IfModel;
024import ch.qos.logback.core.model.conditional.IfModel.BranchState;
025import ch.qos.logback.core.model.processor.ModelHandlerBase;
026import ch.qos.logback.core.model.processor.ModelHandlerException;
027import ch.qos.logback.core.model.processor.ModelInterpretationContext;
028import ch.qos.logback.core.spi.ScanException;
029
030public class IfModelHandler extends ModelHandlerBase {
031
032
033    public static final String MISSING_JANINO_MSG = "Could not find Janino library on the class path. Skipping conditional processing.";
034    public static final String MISSING_JANINO_SEE = "See also " + CoreConstants.CODES_URL + "#ifJanino";
035
036    public static final String BLACKLISTED_REF_DISALLOWED_MSG = "The 'condition' attribute may not contain blacklisted references.";
037    public static final String BLACKLISTED_REF_DISALLOWED_SEE = "See also " + CoreConstants.CODES_URL + "#conditionBlacklisted";
038
039    public static final String UNICODE_DISALLOWED_MSG = "The 'condition' attribute may not contain unicode escape characters.";
040    public static final String UNICODE_DISALLOWED_SEE = "See also " + CoreConstants.CODES_URL + "#conditionUnicode";
041
042
043    public static final String CONDITION_ATTR_DEPRECATED_MSG = "The 'condition' attribute in <if> element is deprecated and slated for removal. Use <condition> element instead.";
044    public static final String CONDITION_ATTR_DEPRECATED_SEE = "See also " + CoreConstants.CODES_URL + "#conditionAttributeDeprecation";
045
046    enum Branch {IF_BRANCH, ELSE_BRANCH; }
047    
048    IfModel ifModel = null;
049    
050    public IfModelHandler(Context context) {
051        super(context);
052    }
053
054    static public ModelHandlerBase makeInstance(Context context, ModelInterpretationContext ic) {
055        return new IfModelHandler(context);
056    }
057
058    @Override
059    protected Class<IfModel> getSupportedModelClass() {
060        return IfModel.class;
061    }
062    
063    @Override
064    public void handle(ModelInterpretationContext mic, Model model) throws ModelHandlerException {
065        
066        ifModel = (IfModel) model;
067        mic.pushModel(ifModel);
068        Object micTopObject = mic.peekObject();
069        String conditionStr = ifModel.getCondition();
070        emitDeprecationWarningIfNecessary(conditionStr);
071
072
073        if(micTopObject instanceof BranchState) {
074            BranchState branchState = (BranchState) micTopObject;
075            ifModel.setBranchState(branchState);
076            // consume the BranchState at top of the object stack
077            mic.popObject();
078        } else {
079            janinoFallback(mic, model, conditionStr);
080        }
081    }
082
083    private void janinoFallback(ModelInterpretationContext mic, Model model, String conditionStr) {
084        if (!EnvUtil.isJaninoAvailable()) {
085            addError(MISSING_JANINO_MSG);
086            addError(MISSING_JANINO_SEE);
087            return;
088        }
089
090        Condition condition = null;
091        int lineNum = model.getLineNumber();
092
093        if (!OptionHelper.isNullOrEmptyOrAllSpaces(conditionStr)) {
094            try {
095                conditionStr = OptionHelper.substVars(conditionStr, mic, context);
096            } catch (ScanException e) {
097               addError("Failed to parse input [" + conditionStr + "] on line "+lineNum, e);
098               ifModel.setBranchState(BranchState.IN_ERROR);
099                return;
100            }
101
102            if(OptionHelper.containsUnicodeEscape(conditionStr)) {
103                addError(UNICODE_DISALLOWED_MSG);
104                addError(UNICODE_DISALLOWED_SEE);
105                return;
106            }
107
108            // do not allow 'new' operator
109            if(hasBlacklistedReferences(conditionStr)) {
110                addError(BLACKLISTED_REF_DISALLOWED_MSG);
111                addError(BLACKLISTED_REF_DISALLOWED_SEE);
112                return;
113            }
114
115            try {
116                PropertyEvalScriptBuilder pesb = new PropertyEvalScriptBuilder(mic);
117                pesb.setContext(context);
118                condition = pesb.build(conditionStr);
119            } catch (Exception|NoClassDefFoundError e) {
120                ifModel.setBranchState(BranchState.IN_ERROR);
121                addError("Failed to parse condition [" + conditionStr + "] on line "+lineNum, e);
122                return;
123            }
124
125            if (condition != null) {
126                boolean boolResult = condition.evaluate();
127                addInfo("Condition ["+conditionStr+"] evaluated to "+boolResult+ " on line "+lineNum);
128                ifModel.setBranchState(boolResult);
129            } else {
130                addError("The condition variable is null. This should not occur.");
131                ifModel.setBranchState(BranchState.IN_ERROR);
132                return;
133            }
134        }
135    }
136
137
138    private void emitDeprecationWarningIfNecessary(String conditionStr) {
139        if(!OptionHelper.isNullOrEmptyOrAllSpaces(conditionStr)) {
140            addWarn(CONDITION_ATTR_DEPRECATED_MSG);
141            addWarn(CONDITION_ATTR_DEPRECATED_SEE);
142        }
143    }
144
145
146    static String[] BLACKLISTED_REFERENCES_IN_CONDITIONAL = new String[] {"new ", "Runtime", "springframework"};
147
148    static boolean hasBlacklistedReferences(String conditionStr) {
149        for (String fishyReference : BLACKLISTED_REFERENCES_IN_CONDITIONAL) {
150            if (conditionStr.contains(fishyReference)) {
151                return true;
152            }
153        }
154        return false;
155    }
156
157    @Override
158    public void postHandle(ModelInterpretationContext mic, Model model) throws ModelHandlerException {
159
160        if(mic.isModelStackEmpty()) {
161            addError("Unexpected unexpected empty model stack.");
162            return;
163        }
164
165        Object o = mic.peekModel();
166        if (o != ifModel) {
167            addWarn("The object [" + o + "] on the top the of the stack is not the expected [" + ifModel);
168        } else {
169            mic.popModel();
170        }
171    }
172
173}