A Tuxedo server hangs at tmboot with Tuxedo 12.1.3, but works fine with 10.0

Question

We have been running a Tuxedo server with pretty much the same logic in the sample code below in our systems for years on AIX (OS level 6100) with Tuxedo 10-32 bit. We are upgrading to Tuxedo 12.1.3 (12cr2) now. The code is compiled fine with Tuxedo 12, however, it just hangs at tmboot. We have tried on multiple servers (all AIX), but it hung on all the servers with tmboot. Is there anyone in the forum ran into the same problem?
The source code ForkSrv.c:
#include <unistd.h>
#include <signal.h>
#include <atmi.h>
void    doChildProcess();
void    launchChildProcess();
static pid_t m_iChildPid = -1;
/** FUNCTION: tpsvrinit */
int tpsvrinit( int argc, char **argv ) {
  launchChildProcess();
  userlog("Service initilized: (pid=%d)\n", getpid());
/* FUNCTION: killChild
*  DESCRIPTION: send SIGTERM to the child process and wait for it terminates.  */
void killChild() {
  int iChildStatus;
  if (m_iChildPid>0)
    kill(m_iChildPid, SIGTERM);
    userlog("Service (pid=%d) kill child process %d\n",
          getpid(), m_iChildPid);
    wait(&iChildStatus);
    userlog("Service (pid=%d) killed child process %d\n",
          getpid(), m_iChildPid);
/** FUNCTION: tpsvrdone
*  DESCRIPTION: terminate the child process and do other clean ups */
void tpsvrdone(void) {
  killChild();
  userlog("Service done: (pid=%d)\n", getpid());
/*  FUNCTION: ForkSvc
*  DESCRIPTION: service function */
void ForkSvc(TPSVCINFO *tpinfo)
  userlog("Service call: (pid=%d)\n", getpid());
  tpreturn(TPSUCCESS, 0, tpinfo->data, 0, 0);
/*  FUNCTION: launchChildProcess
*  DESCRIPTION: launch the child process. If the child process exists terminate it first.  */
void launchChildProcess()
  m_iChildPid = fork();
  switch (m_iChildPid) {
  case -1:/* error */
    userlog("launchChildProcess: Service failed to fork: (pid=%d)\n", getpid());
    break;
  case 0:/* child */
    doChildProcess();
    exit(0);
    break;
  default:/* parent */
    userlog("launchChildProcess: Child created with pid=%d\n", m_iChildPid);
    break;
/*  FUNCTION: doChildProcess
*  DESCRIPTION: child process routing */
void doChildProcess()
  sleep(100000);
  userlog("doChildProcess: Service child exited: (pid=%d)\n", getpid());
  exit(0);
The Makefile fork.mak:
CC=cc
SERVERS=ForkSrv
server: $(SERVERS)
all:ForkSrv
ForkSrv: ForkSrv.o
        buildserver -t -o ForkSrv -s ForkSvc -f ForkSrv.o
ForkSrv.o:ForkSrv.c
        $(CC) -c -I${TUXDIR}/include -o ForkSrv.o ForkSrv.c

Answer 1

We have a tuxedo service which needs to communicate with a POS device by socket. The parent process provides the tuxedo service. The child process provides the connection management for the device. Unnamed pipe is used for communication between the parent and the child. In the child process, there is no code related to tuxedo. The benefit of that design is the tuxedo server does not need to wait for connection from the device when boots up, and the tuxedo service does not need to wait for connection from the device when the service is called.
The tuxedo server was developed 10 years ago, and worked fine till we upgraded tuxedo from 10 to 12 recently. That means it worked for 10 years, and it worked in tuxedo 6.5, tuxedo 10. But in tuxedo 12, tmboot does not return for this tuxedo server. We have to press CTRL-C and yes to cancel. After cancel, the tuxedo service seems working fine.