[omniORB] execv fails under POA, works under BOA

[Dietmar May]

Hello,

I'm seeing a perplexing problem when attempting to exec another program 
when using omniORB.

The code is straightforward: it just does a simple fork, execv, and waitpid.

If run AFTER POA initialization in omniORB 4.0.3, or AFTER BOA 
initialization in omniORB 2.8.0, the child process (apparently) fails 
the execv (because it never completes, even though fork returns a valid 
pid), and the process hangs while waiting for the child.

If run AFTER BOA initialization in omniORB 4.0.3, the program is able to 
fork and exec just fine.

If run BEFORE the ORB_init() call, it works fine in all cases.

I've tried this on two machines. My platforms are RedHat AS 2.1 with 
kernel 2.4.21-4, gcc 2.96-118, and glibc 2.2.4-32.8; and RH 7.2 with 
kernel 2.4.20-20.7, gcc 2.96-118, and glibc 2.2.4-33.

I'm wondering if anyone else can reproduce this problem; and hoping for 
some ideas as to how to fix or work around it.

Regards,
Dietmar

---- cut -- spawn10.cc ----

//works under omniORB 4.0.3 BOA, not 2.8.0 BOA or 4.0.3 POA

//#define USE_POA
//#define OMNI_VERSION  "omniORB2"
#define OMNI_VERSION  "omniORB4"

#include <assert.h>
#include <CORBA.h>

#include <stdio.h>
#include <sys/types.h>
#include <unistd.h>
#include <sys/wait.h>

int  pspawn (const char* const* argv)
{
    assert(argv);

    printf("forking ...\n");
    pid_t pid = fork();
    if(pid == 0)
    {   printf("exec'ing ...\n");
        execv(argv[0], (char**)argv);
        assert(0);  //should never get here       
    }
    printf("continuing...\n");
   
    int ret_code = -1;
    if(pid != -1)                      //if -1 ... not open or already 
waited
    {   int status = 0;
        printf("waiting...\n");
        if(waitpid(pid, &status, 0) != pid)
            printf("PROCESS_WAIT_FAIL");
        else if(WIFEXITED(status))
            ret_code = WEXITSTATUS(status);
        printf("exited...\n");
    }
    return ret_code;
}


char* arg1[] =
{   "/usr/bin/rcs", "-x.rcs", "-i", "-L", "-ko", "-M", "-t-'TEXT'", 
"/tmp/01.rcs", 0
};

char* arg2[] =
{   "/usr/bin/rcs", "-x.rcs", "-i", "-L", "-ko", "-M", "-t-'TEXT'", 
"/tmp/02.rcs", 0
};

char* arg3[] =
{   "/bin/ls", "/tmp", 0
};

int  main(int argc, char **argv)
{
    int code = pspawn(arg3);
    code = pspawn(arg1);

    //start up the CORBA server
#ifdef USE_POA
    CORBA::ORB_var p_ORB = CORBA::ORB_init(argc, argv);
    CORBA::Object_var obj = p_ORB->resolve_initial_references("RootPOA");
    PortableServer::POA_var  p_POA = PortableServer::POA::_narrow(obj);
#else
    CORBA::ORB_ptr p_ORB = CORBA::ORB_init(argc, argv, OMNI_VERSION);
    CORBA::BOA_ptr p_BOA = p_ORB->BOA_init(argc, argv, OMNI_VERSION "_BOA");
#endif

    code = pspawn(arg3);
    code = pspawn(arg2);
    return code;
}

---- cut -- makefile ----

all : spawn_BOA_403 spawn_POA_403
    echo done

spawn_BOA_403 : spawn10.cc
    gcc -o$@ -DUSE_BOA -DLINUX -D_MT -mcpu=i686 -D__linux__ -D__x86__ 
-I/usr/include/omniORB4 -g $< -lc -lpthread -lomnithread -lomniORB4

spawn_POA_403 : spawn10.cc
    gcc -o$@ -DUSE_POA -DLINUX -D_MT -mcpu=i686 -D__linux__ -D__x86__ 
-I/usr/include/omniORB4 -g $< -lc -lpthread -lomnithread -lomniORB4

---- cut -- BOA 4.0.3 output (works) ----

forking ...
exec'ing ...
continuing...
abcdef.tmp 123456.tmp
waiting...
exited...
forking ...
exec'ing ...
RCS file: /tmp/01.rcs
done
continuing...
waiting...
exited...
forking ...
exec'ing ...
continuing...
01.rcs abcdef.tmp 123456.tmp
waiting...
exited...
forking ...
exec'ing ...
RCS file: /tmp/02.rcs
done
continuing...
waiting...
exited...

---- cut -- POA 4.0.3 output (hangs) ----

forking ...
exec'ing ...
continuing...
waiting...
abcdef.tmp 123456.tmp
exited...
forking ...
exec'ing ...
continuing...
waiting...
RCS file: /tmp/01.rcs
done
exited...
forking ...
exec'ing ...
continuing...
waiting...
  <<hangs here>>