java -ea -Xmx8000000000 -jar /storage/repos/ultimate/releaseScripts/default/UAutomizer-linux/plugins/org.eclipse.equinox.launcher_1.3.100.v20150511-1540.jar -data @noDefault -ultimatedata /storage/repos/ultimate/releaseScripts/default/UAutomizer-linux/data -tc ../../../trunk/examples/toolchains/C-BIN-BPP-RCFG.xml -s ../../../trunk/examples/settings/default/automizer/svcomp-Reach-32bit-Automizer_Bitvector.epf -i ../../../trunk/examples/svcomp/ssh/s3_srvr.blast.12_false-unreach-call.i.cil.c


--------------------------------------------------------------------------------


This is Ultimate 0.1.23-217129f
[2018-11-23 17:56:41,343 INFO  L170        SettingsManager]: Resetting all preferences to default values...
[2018-11-23 17:56:41,346 INFO  L174        SettingsManager]: Resetting UltimateCore preferences to default values
[2018-11-23 17:56:41,364 INFO  L177        SettingsManager]: Ultimate Commandline Interface provides no preferences, ignoring...
[2018-11-23 17:56:41,364 INFO  L174        SettingsManager]: Resetting Boogie Preprocessor preferences to default values
[2018-11-23 17:56:41,365 INFO  L174        SettingsManager]: Resetting Boogie Procedure Inliner preferences to default values
[2018-11-23 17:56:41,367 INFO  L174        SettingsManager]: Resetting Abstract Interpretation preferences to default values
[2018-11-23 17:56:41,370 INFO  L174        SettingsManager]: Resetting LassoRanker preferences to default values
[2018-11-23 17:56:41,372 INFO  L174        SettingsManager]: Resetting Reaching Definitions preferences to default values
[2018-11-23 17:56:41,381 INFO  L174        SettingsManager]: Resetting SyntaxChecker preferences to default values
[2018-11-23 17:56:41,382 INFO  L177        SettingsManager]: Büchi Program Product provides no preferences, ignoring...
[2018-11-23 17:56:41,382 INFO  L174        SettingsManager]: Resetting LTL2Aut preferences to default values
[2018-11-23 17:56:41,383 INFO  L174        SettingsManager]: Resetting PEA to Boogie preferences to default values
[2018-11-23 17:56:41,386 INFO  L174        SettingsManager]: Resetting BlockEncodingV2 preferences to default values
[2018-11-23 17:56:41,388 INFO  L174        SettingsManager]: Resetting ChcToBoogie preferences to default values
[2018-11-23 17:56:41,390 INFO  L174        SettingsManager]: Resetting AutomataScriptInterpreter preferences to default values
[2018-11-23 17:56:41,391 INFO  L174        SettingsManager]: Resetting BuchiAutomizer preferences to default values
[2018-11-23 17:56:41,393 INFO  L174        SettingsManager]: Resetting CACSL2BoogieTranslator preferences to default values
[2018-11-23 17:56:41,397 INFO  L174        SettingsManager]: Resetting CodeCheck preferences to default values
[2018-11-23 17:56:41,402 INFO  L174        SettingsManager]: Resetting InvariantSynthesis preferences to default values
[2018-11-23 17:56:41,403 INFO  L174        SettingsManager]: Resetting RCFGBuilder preferences to default values
[2018-11-23 17:56:41,405 INFO  L174        SettingsManager]: Resetting TraceAbstraction preferences to default values
[2018-11-23 17:56:41,407 INFO  L177        SettingsManager]: TraceAbstractionConcurrent provides no preferences, ignoring...
[2018-11-23 17:56:41,407 INFO  L177        SettingsManager]: TraceAbstractionWithAFAs provides no preferences, ignoring...
[2018-11-23 17:56:41,407 INFO  L174        SettingsManager]: Resetting TreeAutomizer preferences to default values
[2018-11-23 17:56:41,410 INFO  L174        SettingsManager]: Resetting IcfgTransformer preferences to default values
[2018-11-23 17:56:41,411 INFO  L174        SettingsManager]: Resetting Boogie Printer preferences to default values
[2018-11-23 17:56:41,412 INFO  L174        SettingsManager]: Resetting ReqPrinter preferences to default values
[2018-11-23 17:56:41,412 INFO  L174        SettingsManager]: Resetting Witness Printer preferences to default values
[2018-11-23 17:56:41,415 INFO  L177        SettingsManager]: Boogie PL CUP Parser provides no preferences, ignoring...
[2018-11-23 17:56:41,415 INFO  L174        SettingsManager]: Resetting CDTParser preferences to default values
[2018-11-23 17:56:41,417 INFO  L177        SettingsManager]: AutomataScriptParser provides no preferences, ignoring...
[2018-11-23 17:56:41,417 INFO  L177        SettingsManager]: ReqParser provides no preferences, ignoring...
[2018-11-23 17:56:41,417 INFO  L174        SettingsManager]: Resetting SmtParser preferences to default values
[2018-11-23 17:56:41,418 INFO  L174        SettingsManager]: Resetting Witness Parser preferences to default values
[2018-11-23 17:56:41,421 INFO  L181        SettingsManager]: Finished resetting all preferences to default values...
[2018-11-23 17:56:41,421 INFO  L98         SettingsManager]: Beginning loading settings from /storage/repos/ultimate/releaseScripts/default/UAutomizer-linux/../../../trunk/examples/settings/default/automizer/svcomp-Reach-32bit-Automizer_Bitvector.epf
[2018-11-23 17:56:41,449 INFO  L110        SettingsManager]: Loading preferences was successful
[2018-11-23 17:56:41,449 INFO  L112        SettingsManager]: Preferences different from defaults after loading the file:
[2018-11-23 17:56:41,450 INFO  L131        SettingsManager]: Preferences of Boogie Procedure Inliner differ from their defaults:
[2018-11-23 17:56:41,450 INFO  L133        SettingsManager]:  * ... calls to implemented procedures=ONLY_FOR_CONCURRENT_PROGRAMS
[2018-11-23 17:56:41,451 INFO  L131        SettingsManager]: Preferences of BlockEncodingV2 differ from their defaults:
[2018-11-23 17:56:41,451 INFO  L133        SettingsManager]:  * Create parallel compositions if possible=false
[2018-11-23 17:56:41,451 INFO  L133        SettingsManager]:  * Use SBE=true
[2018-11-23 17:56:41,451 INFO  L131        SettingsManager]: Preferences of CACSL2BoogieTranslator differ from their defaults:
[2018-11-23 17:56:41,453 INFO  L133        SettingsManager]:  * sizeof long=4
[2018-11-23 17:56:41,453 INFO  L133        SettingsManager]:  * sizeof POINTER=4
[2018-11-23 17:56:41,453 INFO  L133        SettingsManager]:  * Check division by zero=IGNORE
[2018-11-23 17:56:41,454 INFO  L133        SettingsManager]:  * Pointer to allocated memory at dereference=IGNORE
[2018-11-23 17:56:41,454 INFO  L133        SettingsManager]:  * If two pointers are subtracted or compared they have the same base address=IGNORE
[2018-11-23 17:56:41,454 INFO  L133        SettingsManager]:  * Check array bounds for arrays that are off heap=IGNORE
[2018-11-23 17:56:41,454 INFO  L133        SettingsManager]:  * Use bitvectors instead of ints=true
[2018-11-23 17:56:41,454 INFO  L133        SettingsManager]:  * Memory model=HoenickeLindenmann_4ByteResolution
[2018-11-23 17:56:41,455 INFO  L133        SettingsManager]:  * sizeof long double=12
[2018-11-23 17:56:41,455 INFO  L133        SettingsManager]:  * Check if freed pointer was valid=false
[2018-11-23 17:56:41,455 INFO  L133        SettingsManager]:  * Use constant arrays=true
[2018-11-23 17:56:41,455 INFO  L133        SettingsManager]:  * Pointer base address is valid at dereference=IGNORE
[2018-11-23 17:56:41,456 INFO  L131        SettingsManager]: Preferences of RCFGBuilder differ from their defaults:
[2018-11-23 17:56:41,456 INFO  L133        SettingsManager]:  * Size of a code block=SequenceOfStatements
[2018-11-23 17:56:41,456 INFO  L133        SettingsManager]:  * To the following directory=./dump/
[2018-11-23 17:56:41,456 INFO  L133        SettingsManager]:  * SMT solver=External_DefaultMode
[2018-11-23 17:56:41,456 INFO  L133        SettingsManager]:  * Command for external solver=z3 SMTLIB2_COMPLIANT=true -memory:2024 -smt2 -in -t:2000
[2018-11-23 17:56:41,458 INFO  L131        SettingsManager]: Preferences of TraceAbstraction differ from their defaults:
[2018-11-23 17:56:41,459 INFO  L133        SettingsManager]:  * Compute Interpolants along a Counterexample=FPandBP
[2018-11-23 17:56:41,459 INFO  L133        SettingsManager]:  * Positions where we compute the Hoare Annotation=LoopsAndPotentialCycles
[2018-11-23 17:56:41,459 INFO  L133        SettingsManager]:  * Trace refinement strategy=WOLF
[2018-11-23 17:56:41,459 INFO  L133        SettingsManager]:  * SMT solver=External_ModelsAndUnsatCoreMode
[2018-11-23 17:56:41,459 INFO  L133        SettingsManager]:  * Command for external solver=cvc4 --incremental --rewrite-divk --print-success --lang smt
[2018-11-23 17:56:41,460 INFO  L133        SettingsManager]:  * Logic for external solver=AUFBV
[2018-11-23 17:56:41,460 INFO  L133        SettingsManager]:  * Compute Hoare Annotation of negated interpolant automaton, abstraction and CFG=true
[2018-11-23 17:56:41,526 INFO  L81    nceAwareModelManager]: Repository-Root is: /tmp
[2018-11-23 17:56:41,543 INFO  L258   ainManager$Toolchain]: [Toolchain 1]: Applicable parser(s) successfully (re)initialized
[2018-11-23 17:56:41,548 INFO  L214   ainManager$Toolchain]: [Toolchain 1]: Toolchain selected.
[2018-11-23 17:56:41,549 INFO  L271        PluginConnector]: Initializing CDTParser...
[2018-11-23 17:56:41,550 INFO  L276        PluginConnector]: CDTParser initialized
[2018-11-23 17:56:41,551 INFO  L418   ainManager$Toolchain]: [Toolchain 1]: Parsing single file: /storage/repos/ultimate/releaseScripts/default/UAutomizer-linux/../../../trunk/examples/svcomp/ssh/s3_srvr.blast.12_false-unreach-call.i.cil.c
[2018-11-23 17:56:41,626 INFO  L221              CDTParser]: Created temporary CDT project at /storage/repos/ultimate/releaseScripts/default/UAutomizer-linux/data/5a8c6b1e6/50f38142d5394d718a9fb96fd491e1b3/FLAG11e0d6373
[2018-11-23 17:56:42,217 INFO  L307              CDTParser]: Found 1 translation units.
[2018-11-23 17:56:42,218 INFO  L161              CDTParser]: Scanning /storage/repos/ultimate/trunk/examples/svcomp/ssh/s3_srvr.blast.12_false-unreach-call.i.cil.c
[2018-11-23 17:56:42,247 INFO  L355              CDTParser]: About to delete temporary CDT project at /storage/repos/ultimate/releaseScripts/default/UAutomizer-linux/data/5a8c6b1e6/50f38142d5394d718a9fb96fd491e1b3/FLAG11e0d6373
[2018-11-23 17:56:42,426 INFO  L363              CDTParser]: Successfully deleted /storage/repos/ultimate/releaseScripts/default/UAutomizer-linux/data/5a8c6b1e6/50f38142d5394d718a9fb96fd491e1b3
[2018-11-23 17:56:42,437 INFO  L296   ainManager$Toolchain]: ####################### [Toolchain 1] #######################
[2018-11-23 17:56:42,439 INFO  L131        ToolchainWalker]: Walking toolchain with 4 elements.
[2018-11-23 17:56:42,440 INFO  L113        PluginConnector]: ------------------------CACSL2BoogieTranslator----------------------------
[2018-11-23 17:56:42,440 INFO  L271        PluginConnector]: Initializing CACSL2BoogieTranslator...
[2018-11-23 17:56:42,444 INFO  L276        PluginConnector]: CACSL2BoogieTranslator initialized
[2018-11-23 17:56:42,446 INFO  L185        PluginConnector]: Executing the observer ACSLObjectContainerObserver from plugin CACSL2BoogieTranslator for "CDTParser AST 23.11 05:56:42" (1/1) ...
[2018-11-23 17:56:42,449 INFO  L205        PluginConnector]: Invalid model from CACSL2BoogieTranslator for observer de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator.ACSLObjectContainerObserver@763c6e86 and model type de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 23.11 05:56:42, skipping insertion in model container
[2018-11-23 17:56:42,450 INFO  L185        PluginConnector]: Executing the observer CACSL2BoogieTranslatorObserver from plugin CACSL2BoogieTranslator for "CDTParser AST 23.11 05:56:42" (1/1) ...
[2018-11-23 17:56:42,461 INFO  L145         MainTranslator]: Starting translation in SV-COMP mode 
[2018-11-23 17:56:42,552 INFO  L176         MainTranslator]: Built tables and reachable declarations
[2018-11-23 17:56:43,168 INFO  L201          PostProcessor]: Analyzing one entry point: main
[2018-11-23 17:56:43,191 INFO  L191         MainTranslator]: Completed pre-run
[2018-11-23 17:56:43,507 INFO  L201          PostProcessor]: Analyzing one entry point: main
[2018-11-23 17:56:43,551 INFO  L195         MainTranslator]: Completed translation
[2018-11-23 17:56:43,551 INFO  L202        PluginConnector]: Adding new model de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 23.11 05:56:43 WrapperNode
[2018-11-23 17:56:43,552 INFO  L132        PluginConnector]: ------------------------ END CACSL2BoogieTranslator----------------------------
[2018-11-23 17:56:43,553 INFO  L113        PluginConnector]: ------------------------Boogie Procedure Inliner----------------------------
[2018-11-23 17:56:43,553 INFO  L271        PluginConnector]: Initializing Boogie Procedure Inliner...
[2018-11-23 17:56:43,553 INFO  L276        PluginConnector]: Boogie Procedure Inliner initialized
[2018-11-23 17:56:43,562 INFO  L185        PluginConnector]: Executing the observer TypeChecker from plugin Boogie Procedure Inliner for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 23.11 05:56:43" (1/1) ...
[2018-11-23 17:56:43,594 INFO  L185        PluginConnector]: Executing the observer Inliner from plugin Boogie Procedure Inliner for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 23.11 05:56:43" (1/1) ...
[2018-11-23 17:56:43,605 INFO  L132        PluginConnector]: ------------------------ END Boogie Procedure Inliner----------------------------
[2018-11-23 17:56:43,606 INFO  L113        PluginConnector]: ------------------------Boogie Preprocessor----------------------------
[2018-11-23 17:56:43,606 INFO  L271        PluginConnector]: Initializing Boogie Preprocessor...
[2018-11-23 17:56:43,606 INFO  L276        PluginConnector]: Boogie Preprocessor initialized
[2018-11-23 17:56:43,617 INFO  L185        PluginConnector]: Executing the observer EnsureBoogieModelObserver from plugin Boogie Preprocessor for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 23.11 05:56:43" (1/1) ...
[2018-11-23 17:56:43,617 INFO  L185        PluginConnector]: Executing the observer TypeChecker from plugin Boogie Preprocessor for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 23.11 05:56:43" (1/1) ...
[2018-11-23 17:56:43,628 INFO  L185        PluginConnector]: Executing the observer ConstExpander from plugin Boogie Preprocessor for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 23.11 05:56:43" (1/1) ...
[2018-11-23 17:56:43,629 INFO  L185        PluginConnector]: Executing the observer StructExpander from plugin Boogie Preprocessor for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 23.11 05:56:43" (1/1) ...
[2018-11-23 17:56:43,728 INFO  L185        PluginConnector]: Executing the observer UnstructureCode from plugin Boogie Preprocessor for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 23.11 05:56:43" (1/1) ...
[2018-11-23 17:56:43,745 INFO  L185        PluginConnector]: Executing the observer FunctionInliner from plugin Boogie Preprocessor for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 23.11 05:56:43" (1/1) ...
[2018-11-23 17:56:43,749 INFO  L185        PluginConnector]: Executing the observer BoogieSymbolTableConstructor from plugin Boogie Preprocessor for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 23.11 05:56:43" (1/1) ...
[2018-11-23 17:56:43,757 INFO  L132        PluginConnector]: ------------------------ END Boogie Preprocessor----------------------------
[2018-11-23 17:56:43,757 INFO  L113        PluginConnector]: ------------------------RCFGBuilder----------------------------
[2018-11-23 17:56:43,758 INFO  L271        PluginConnector]: Initializing RCFGBuilder...
[2018-11-23 17:56:43,758 INFO  L276        PluginConnector]: RCFGBuilder initialized
[2018-11-23 17:56:43,759 INFO  L185        PluginConnector]: Executing the observer RCFGBuilderObserver from plugin RCFGBuilder for "de.uni_freiburg.informatik.ultimate.plugins.generator.cacsl2boogietranslator AST 23.11 05:56:43" (1/1) ...
No working directory specified, using /storage/repos/ultimate/releaseScripts/default/UAutomizer-linux/z3
Starting monitored process 1 with z3 SMTLIB2_COMPLIANT=true -memory:2024 -smt2 -in -t:2000 (exit command is (exit), workingDir is null)
Waiting until toolchain timeout for monitored process 1 with z3 SMTLIB2_COMPLIANT=true -memory:2024 -smt2 -in -t:2000
[2018-11-23 17:56:43,823 INFO  L130     BoogieDeclarations]: Found specification of procedure write~init~$Pointer$
[2018-11-23 17:56:43,823 INFO  L130     BoogieDeclarations]: Found specification of procedure main
[2018-11-23 17:56:43,823 INFO  L138     BoogieDeclarations]: Found implementation of procedure main
[2018-11-23 17:56:43,823 INFO  L130     BoogieDeclarations]: Found specification of procedure write~init~intINTTYPE4
[2018-11-23 17:56:43,824 INFO  L130     BoogieDeclarations]: Found specification of procedure write~$Pointer$
[2018-11-23 17:56:43,824 INFO  L130     BoogieDeclarations]: Found specification of procedure #Ultimate.alloc
[2018-11-23 17:56:43,824 INFO  L130     BoogieDeclarations]: Found specification of procedure read~intINTTYPE4
[2018-11-23 17:56:43,824 INFO  L130     BoogieDeclarations]: Found specification of procedure read~$Pointer$
[2018-11-23 17:56:43,824 INFO  L130     BoogieDeclarations]: Found specification of procedure ssl3_accept
[2018-11-23 17:56:43,826 INFO  L138     BoogieDeclarations]: Found implementation of procedure ssl3_accept
[2018-11-23 17:56:43,826 INFO  L130     BoogieDeclarations]: Found specification of procedure ULTIMATE.init
[2018-11-23 17:56:43,826 INFO  L138     BoogieDeclarations]: Found implementation of procedure ULTIMATE.init
[2018-11-23 17:56:43,826 INFO  L130     BoogieDeclarations]: Found specification of procedure ULTIMATE.start
[2018-11-23 17:56:43,826 INFO  L138     BoogieDeclarations]: Found implementation of procedure ULTIMATE.start
[2018-11-23 17:56:43,828 INFO  L130     BoogieDeclarations]: Found specification of procedure write~intINTTYPE4
[2018-11-23 17:56:44,477 WARN  L645   $ProcedureCfgBuilder]: Two Gotos in a row! There was dead code
[2018-11-23 17:56:44,478 WARN  L610   $ProcedureCfgBuilder]: Label in the middle of a codeblock.
[2018-11-23 17:56:50,119 INFO  L275             CfgBuilder]: Using the 1 location(s) as analysis (start of procedure ULTIMATE.start)
[2018-11-23 17:56:50,119 INFO  L280             CfgBuilder]: Removed 1 assue(true) statements.
[2018-11-23 17:56:50,120 INFO  L202        PluginConnector]: Adding new model de.uni_freiburg.informatik.ultimate.plugins.generator.rcfgbuilder CFG 23.11 05:56:50 BoogieIcfgContainer
[2018-11-23 17:56:50,120 INFO  L132        PluginConnector]: ------------------------ END RCFGBuilder----------------------------
[2018-11-23 17:56:50,122 INFO  L168              Benchmark]: Toolchain (without parser) took 7684.44 ms. Allocated memory was 1.5 GB in the beginning and 2.3 GB in the end (delta: 738.7 MB). Free memory was 1.4 GB in the beginning and 2.0 GB in the end (delta: -611.4 MB). Peak memory consumption was 127.3 MB. Max. memory is 7.1 GB.
[2018-11-23 17:56:50,125 INFO  L168              Benchmark]: CDTParser took 0.22 ms. Allocated memory is still 1.5 GB. Free memory is still 1.5 GB. There was no memory consumed. Max. memory is 7.1 GB.
[2018-11-23 17:56:50,125 INFO  L168              Benchmark]: CACSL2BoogieTranslator took 1112.10 ms. Allocated memory was 1.5 GB in the beginning and 2.3 GB in the end (delta: 738.7 MB). Free memory was 1.4 GB in the beginning and 2.2 GB in the end (delta: -771.5 MB). Peak memory consumption was 51.9 MB. Max. memory is 7.1 GB.
[2018-11-23 17:56:50,126 INFO  L168              Benchmark]: Boogie Procedure Inliner took 53.26 ms. Allocated memory is still 2.3 GB. Free memory is still 2.2 GB. There was no memory consumed. Max. memory is 7.1 GB.
[2018-11-23 17:56:50,127 INFO  L168              Benchmark]: Boogie Preprocessor took 150.98 ms. Allocated memory is still 2.3 GB. Free memory is still 2.2 GB. There was no memory consumed. Max. memory is 7.1 GB.
[2018-11-23 17:56:50,127 INFO  L168              Benchmark]: RCFGBuilder took 6362.89 ms. Allocated memory is still 2.3 GB. Free memory was 2.2 GB in the beginning and 2.0 GB in the end (delta: 160.1 MB). Peak memory consumption was 160.1 MB. Max. memory is 7.1 GB.
[2018-11-23 17:56:50,132 INFO  L336   ainManager$Toolchain]: #######################  End [Toolchain 1] #######################
 --- Results ---
 * Results from de.uni_freiburg.informatik.ultimate.core:
  - GenericResult: Assertions are enabled
    Assertions are enabled
  - StatisticsResult: Toolchain Benchmarks
    Benchmark results are:
 * CDTParser took 0.22 ms. Allocated memory is still 1.5 GB. Free memory is still 1.5 GB. There was no memory consumed. Max. memory is 7.1 GB.
 * CACSL2BoogieTranslator took 1112.10 ms. Allocated memory was 1.5 GB in the beginning and 2.3 GB in the end (delta: 738.7 MB). Free memory was 1.4 GB in the beginning and 2.2 GB in the end (delta: -771.5 MB). Peak memory consumption was 51.9 MB. Max. memory is 7.1 GB.
 * Boogie Procedure Inliner took 53.26 ms. Allocated memory is still 2.3 GB. Free memory is still 2.2 GB. There was no memory consumed. Max. memory is 7.1 GB.
 * Boogie Preprocessor took 150.98 ms. Allocated memory is still 2.3 GB. Free memory is still 2.2 GB. There was no memory consumed. Max. memory is 7.1 GB.
 * RCFGBuilder took 6362.89 ms. Allocated memory is still 2.3 GB. Free memory was 2.2 GB in the beginning and 2.0 GB in the end (delta: 160.1 MB). Peak memory consumption was 160.1 MB. Max. memory is 7.1 GB.
RESULT: Ultimate could not prove your program: Toolchain returned no result.
Received shutdown request...