gcc3.2 coredump in exception handling
Shen Wu
I have coredump for exception handling in a c++ program using dynamic
library compiled with
gcc3.2. We wrote the main program (mainapp) using dlopen to load a libsub.so
and execute
functions in so with dlsym. In the libsub.so we throw an exception and
catch it the mainapp.
We have gcc3.2, gcc3.2.1 and gcc3.2.2 compiled natively with GNU GCC source
and gcc3.2 coming with Redhat 8.0.
It coredumps in gcc library for exception handling if we compile one of them
in RH gcc3.2
and one in our own gcc3.2.x and run under our gcc3.2.x. It works fine in the
same
coredump case above if we run them under RH gcc3.2. In addition, the
program works
fine if we compile mainapp and libsub.so using our gcc3.2.x in any
combination
such as we compile mainapp in gcc3.2 and libsub.so in gcc3.2.2 or vice versa
and run under any version of our gcc3.2.x. We also have the right result
if we compile both of them in RH gcc3.2.
There are some compatibility problems between our gcc3.2.x and gcc3.2 in
Redhat 8.0
and the problem only presented in the exception handling part not the other
normal function calls.
Has anyone encounter the same problem?
Does anyone know what is special in Redhat gcc3.2.
Any help will be greatly appreciated.
-Shen
P.S. I know the case is kind of complicated and I hope I mention it clear
enough
for you to understand it. All the detailed info is shown below.
1) mainapp.cpp (creates mainapp)
#include <dlfcn.h>
#include <iostream>
using namespace std;
typedef int (*intfunc) (int, int);
typedef int (*throwfunc) ();
int main()
{
void* pluginHandle = 0;
char* pluginLib = "./libsub.so";
void* gData = 0;
int result = 0;
char* error = 0;
intfunc func1;
throwfunc func2;
try {
pluginHandle = dlopen(pluginLib, RTLD_LAZY);
if (pluginHandle) {
cout << "!! load dll success !!\n";
gData = dlsym(pluginHandle, "gInt");
if ((error = dlerror()) != NULL) {
cout << "dlsym(global1) failed with error<" << error <<
">\n";
return (-1);
}
cout << "\tthe global value is <" << *((int*)(gData)) << ">\n";
func1 = (intfunc)dlsym(pluginHandle, "addInt");
if ((error = dlerror()) != NULL) {
cout << "dlsym(addInt) failed with error<" << error <<
">\n";
return (-1);
}
result = (*func1)(5, 8);
cout << "\tthe function call result is <" << result << ">\n\n";
func2 = (throwfunc)dlsym(pluginHandle, "throwException");
if ((error = dlerror()) != NULL) {
cout << "dlsym(throwException) failed with error<" << error
<< ">\n";
return (-1);
}
result = (*func2)();
dlclose(pluginHandle);
pluginHandle = 0;
} else {
cout << "dlopen failed with error <" << dlerror() << ">\n";
return (-1);
}
} catch (std::string& s) {
cout << "Caught Exception <" << s << ">!" << endl << endl;
if (pluginHandle) {
dlclose(pluginHandle);
}
return (-1);
}
return 0;
}
2) sub.cpp which generates libsub.so
#include <iostream>
int gInt = 5;
extern "C" {
int addInt(int a, int b)
{
std::cout << "Enter addInt ...\n";
return a + b;
}
int throwException()
throw (std::string)
{
throw std::string("Thrown from shared lib");
}
}
3) Makefile
all: libsub.so mainapp
libsub.so:
g++ -g -Wall -c -o sub.o sub.cpp
g++ -shared -o libsub.so sub.o
mainapp: libsub.so
g++ -g -Wall -c -o mainapp.o mainapp.cpp
g++ mainapp.o -L. -lsub -ldl -o mainapp
clean:
rm -f *.o libsub.so mainapp core*
4) correct output:
!! load dll success !!
the global value is <5>
Enter addInt ...
the function call result is <13>
Caught Exception <Thrown from shared lib>!
5) wrong result
!! load dll success !!
the global value is <5>
Enter addInt ...
the function call result is <13>
Abort (core dumped)
6) Core stack:
#0 0x4013ba01 in __kill () at __kill:-1
#1 0x4013b7da in raise (sig=6) at ../sysdeps/posix/raise.c:27
#2 0x4013cf82 in abort () at ../sysdeps/generic/abort.c:88
#3 0x400b7924 in __cxxabiv1::__terminate(void (*)()) (handler=0x4013ce24
<abort>) at ../../../../libstdc++-v3/libsupc++/eh_terminate.cc:47
#4 0x400b7968 in std::terminate() ()
at ../../../../libstdc++-v3/libsupc++/eh_terminate.cc:57
#5 0x400b7ab5 in __cxa_throw (obj=0x804ab60, tinfo=0x400c4344,
dest=0x400c4344 <__cxxabiv1::__terminate_handler>)
at ../../../../libstdc++-v3/libsupc++/eh_throw.cc:77
#6 0x40018ca5 in throwException () at sub.cpp:16
#7 0x08048d44 in main () at mainapp.cpp:45
#8 0x40129507 in __libc_start_main (main=0x8048b2c <main>, argc=1,
ubp_av=0xbffff4d4, init=0x80488e4 <_init>, fini=0x8048f04 <_fini>,
rtld_fini=0x4000dc14 <_dl_fini>, stack_end=0xbffff4cc)
at ../sysdeps/generic/libc-start.c:129
7) our gcc3.2 configuration info (gcc -v)
Reading specs from /pcc/app/gcc3.2/lib/gcc-lib/i386-redhat-linux/3.2/specs
Configured with:
../configure --prefix=/pcc/app/gcc3.2 --mandir=/pcc/app/gcc3.2/share/man --i
nfodir=/pcc/app/gcc3.2/share/info --enable-shared --enable-threads=posix
--disable-checking --host=i386-redhat-linux --with-system-zlib
--enable-languages=c,c++ --enable-__cxa_atexit
Thread model: posix
gcc version 3.2
8) Redhat 8.0 gcc3.2 info (gcc -v)
Reading specs from /usr/lib/gcc-lib/i386-redhat-linux/3.2/specs
Configured with:
../configure --prefix=/usr --mandir=/usr/share/man --infodir=/usr/share/info
--enable-shared --enable-threads=posix --disable-checking --host=i386-redhat
-linux
--with-system-zlib --enable-__cxa_atexit
Thread model: posix
gcc version 3.2 20020903 (Red Hat Linux 8.0 3.2-7)