PM48459: TTCN generated code causes memory leak (esc TLOG#66261)

APAR status

• Closed as program error.

Error description

• TTCN generated code causes memory leak.
  

Local fix

Problem summary

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  * USERS AFFECTED:                                              *
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  * PROBLEM DESCRIPTION:                                         *
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  Memory leaks can occur when allocating permanent memory when
  defining TTCN User defined operations.
  

Problem conclusion

• Documentation on how to use permanent memory has been added
  to help:
  
  The following comment has been added to TTCN Suite
  documentation into the chapter TTCN Suite Methodology
  Guidelines --? 1 The TTCN Introduction --? TTCN Expressions
  --? TTCN Operations --? User Defined Operations :
  
  Note:
  Since TTCN Suite operations are implemented manually with
  the means of target language, pay careful attention to the
  way memory is allocated/freed inside an operation.
  
  There are 2 types of memory TTCN runtime is using: permanent
  memory and temporary memory.
  Permanent memory is used for permanent test case entities
  (like variables) that live longer than one step(one line) of
  a test case,
  temporary memory is used for temporary values that are
  created during execution of one step of a test case.
  
  Temporary memory is automatically released after execution
  of each line of a test case:
  
  IcGetTemporaryMemoryStart(?tmpmem_mark);
  prev_line = line;
  switch (line) {
  case 1:
  ...
  case 2:
  ...
  }
  ...
  IcReleaseTemporaryMemory(tmpmem_mark);
  
  
  IcGetTemporaryMemoryStart(?tmpmem_mark) is called before
  line execution, IcReleaseTemporaryMemory(tmpmem_mark) is
  called after line execution.
  
  Temporary memory is a preallocated memory buffer. void*
  VCMALLOC(unsigned int size, Bool temporary) function has got
  a parameter "Bool temporary"
  that says if allocated memory should be acquired from the
  preallocated memory buffer. If it is GcFALSE the system
  allocation function malloc will be called
  to create new memory. void VCFREE(void* ptr) deallocates
  allocated memory, but if the memory is temporary the
  function will do nothing.
  There is a Bool IcIsTemporary(void* pointer) predicate that
  checks if a pointer is in the temporary heap.
  void IcGetTemporaryMemoryStart(IcTmpMemMark *mark) and void
  IcReleaseTemporaryMemory(IcTmpMemMark pos) functions are
  used to save the position in temporary memory heap and
  sometime later release all memory acquired after that
  position.
  
  
  Test Suite Operation parameters are passed by value and all
  parameters are allocated in temporary memory during
  operation call. If an operation returns some value to the
  test suite, it is also expected to be allocated in temporary
  memory. Returned value is assigned to some further value,
  and it is not freed with a separate command.
  
  For example, test suite operation that converts a hex string
  to bit string should create the result value like this:
  result = VcMkTempValue(GcBITSTRINGD);
  EGciSetSTRING(result, bstr);
  
  Using GciMkBIT_STRING(bstr) function for creating return
  value will lead to memory leaks, because the value will be
  allocated in permanent memory and it will not be
  automatically freed.
  

Temporary fix

Comments

APAR Information

• APAR is sysrouted FROM one or more of the following:

• APAR is sysrouted TO one or more of the following:

Fix information

• Fixed component name

  TLOGIC TTCN SUI

• Fixed component ID

  5724V78TT

Applicable component levels

• R630 PSN

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