Experimental Physics and
Industrial Control System

Till Straumann <[email protected]> · Mon, 11 Jun 2007 11:14:05 -0700

Kate Feng wrote:

EPICS  OSI Release : 3.14.x   ( at least 3.14.6 and up )
File : src/libCom/osi/os/RTEMS/osdPoolStatus.c
Problem :

"return (malloc_free_space() > 50000 + contiguousBlockSize);"

will falsely return true when RTEMS function call

malloc_free_space() returns -1, which actually indicates

an internal RTEMS error such as corrupted heap,or illegal

region id etc. Since neither EPICS nor RTEMS prints out

the error condition, this kind of error could be hard to be

debugged.

In most cases heap corruption results due to programming
errors (rather than internal errors) which emphasizes
Kate's point. osdPoolStatus should check
the return state of malloc_free_space(). However,
I'd suggest more drastic measures than just returning 0
such as printing a console message and aborting the
application.
Anyways, under RTEMS 4.8 the implementation has
changed and AFAIK malloc_free_space() can no longer
return -1.
T.

FIX : src/libCom/osi/os/RTEMS/osdPoolStatus.c
return ( ((int) malloc_free_space()) > 50000 + contiguousBlockSize);
Or I actually preferred something like :
/*
 * osiSufficentSpaceInPool ()
 */
epicsShareFunc int epicsShareAPI osiSufficentSpaceInPool ( size_t
contiguousBlockSize )
{
  int free;
  if ( (free=malloc_free_space())==-1)
     return(0);
  if ( free < 100000 + contiguousBlockSize) {
    printf("Largest free space available : 0x%x,  requested
contiguousBlockSize : 0x%x\n",
    free, contiguousBlockSize);
    return(0);
  }
  return(1);
}
Besides, RTEMS should print out what the internal error message is.
Regards,
Kate

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System