Intel Software Network - <![CDATA[ Signal Handler on a Linux system. ]]> feed http://software.intel.com/en-us/forums/intel-c-compiler/topic/66465 en-us Re: Signal Handler on a Linux system.
I could not compile the secod case even with gcc. Could you please help with compilable test case with gcc and command line.   ]]> http://software.intel.com/en-us/forums/intel-c-compiler/topic/66465/ Tue, 23 Jun 2009 22:43:39 -0700 http://software.intel.com/en-us/forums/intel-c-compiler/topic/66465/ ISN General Re: Signal Handler on a Linux system.

I could not compile the secod case even with gcc. Could you please help with compilable test case with gcc and command line.  

That is what my problem is, the structure with sa_sigaction exists in the sigaction.h include file, it also does incorporate the 3 return arguments (instead of just signo), but I cannot get it to compile on our system.  This solution was one I found on the internet after searching for signal handlers on Linux systems.  I tried a plethera of different #define flags to see if I could force it to use the correct version of the sigaction structure with the added arguments, but to no avail.  I cannot get this to work on the Linux system using gcc or icc.  Is there another way to do it using icc?  I have to be able to capture the signal, print the call stack, and re-display the Motif window notifying the operator that a signal was caught so that they can gracefully exit the process and notify a analyst to take a look at it.  The call stack printing is to assist the analyst with what the process was doing when it received a signal.  Everything works with the first solution, except that it prints the "new" call stack containing just the signal handler information.  The only solution I can find to get to the previous stack frame "old" call stack, was the routine #2 solution.  According to the include files on the system, the system should support the second solution, I just can't figure out what I am missing to get it to compile. ]]> http://software.intel.com/en-us/forums/intel-c-compiler/topic/66465/ Wed, 24 Jun 2009 07:11:05 -0700 http://software.intel.com/en-us/forums/intel-c-compiler/topic/66465/ ISN General Re: Signal Handler on a Linux system. Mark, one of my colleagues, fixed syntax error in your code. That makes the code works on IA-32.


================== t2.cpp for IA32 ================
#define _POSIX_SOURCE 199309

#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include <execinfo.h>
#include <setjmp.h>
#include <unistd.h>

#define __USE_GNU 1
#include <sys/ucontext.h>



void MyStackWalker (siginfo_t *info, void *my_eip)
{
void *trace[10];
int i;
int trace_size = 0;
char **messages = (char**)NULL;
trace_size = backtrace(trace, 10);
messages = backtrace_symbols(trace, trace_size);
ucontext_t *uc = (ucontext_t *)my_eip;
trace[1] = (void*)uc->uc_mcontext.gregs[REG_RIP];
for (i=0; i<trace_size; i++)
{
printf("\n[bt] %s", messages[i]);
}
free (messages);
}
void MySignalHandler (int signo, siginfo_t *info, void *my_eip)
{
if (signo == SIGFPE)
{
printf("\n A floating point exception has been detected.");
MyStackWalker(info, my_eip);
}
else if (signo == SIGSEGV)
{
printf("\n A segmentation violation has been detected.");
MyStackWalker(info, my_eip);
}
else if (signo == SIGILL)
{
printf("\n An illegal operation has been detected.");
MyStackWalker(info, my_eip);
}
else if (signo == SIGTRAP)
{
printf("\n A out of bounds array has been detected.");
MyStackWalker(info, my_eip);
}
else
{
printf("\n An unknown exception has been detected.");
MyStackWalker(info, my_eip);
}
}
int main()
{
struct sigaction newAct;
newAct.sa_sigaction= &MySignalHandler;
sigemptyset (&newAct.sa_mask);
newAct.sa_flags = SA_RESTART | SA_SIGINFO;
sigaction(SIGFPE, &newAct, NULL);
sigaction(SIGILL, &newAct, NULL);
sigaction(SIGSEGV, &newAct, NULL);
sigaction(SIGTRAP, &newAct, NULL);
}
============================================

$ icc -V
Intel(R) C Compiler Professional for applications running on IA-32, Version 11.0 Build 20090609 Package ID: l_cproc_p_11.0.084
Copyright (C) 1985-2009 Intel Corporation. All rights reserved.

$ icpc t2.cpp
$ g++ t2.cpp
$


However, above code doesn't compile on Intel 64.  Then I did some further investigation.It looks that REG_EIP only works on IA-32. In /usr/include/sys/ucontext.h, you may see something like this


#if __WORDSIZE == 64
...
enum
{
REG_R8 = 0,
# define REG_R8 REG_R8
REG_R9,
# define REG_R9 REG_R9
REG_R10,
# define REG_R10 REG_R10
REG_R11,
...
REG_RIP,
# define REG_RIP REG_RIP
...
};

#else /* __WORDSIZE == 32 */

enum
{
...
REG_EIP,
# define REG_EIP REG_EIP
REG_CS,
# define REG_CS REG_CS
REG_EFL,
# define REG_EFL REG_EFL
REG_UESP,
# define REG_UESP REG_UESP
REG_SS
# define REG_SS REG_SS
};
#endif


So, on IA-32, REG_EIP is an enum value. But on Intel 64, REG_EIP is not defined.  It seems that you should use REG_RIP instead on Intel 64.  With this modification, t2.cpp compiles.  See below.


=========== t2.cpp for Intel 64 ================
#define _POSIX_SOURCE 199309

#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include <execinfo.h>
#include <setjmp.h>
#include <unistd.h>

#define __USE_GNU 1
#include <sys/ucontext.h>



void MyStackWalker (siginfo_t *info, void *my_eip)
{
void *trace[10];
int i;
int trace_size = 0;
char **messages = (char**)NULL;
trace_size = backtrace(trace, 10);
messages = backtrace_symbols(trace, trace_size);
ucontext_t *uc = (ucontext_t *)my_eip;
trace[1] = (void*)uc->uc_mcontext.gregs[REG_RIP];
for (i=0; i<trace_size; i++)
{
printf("\n[bt] %s", messages[i]);
}
free (messages);
}
void MySignalHandler (int signo, siginfo_t *info, void *my_eip)
{
if (signo == SIGFPE)
{
printf("\n A floating point exception has been detected.");
MyStackWalker(info, my_eip);
}
else if (signo == SIGSEGV)
{
printf("\n A segmentation violation has been detected.");
MyStackWalker(info, my_eip);
}
else if (signo == SIGILL)
{
printf("\n An illegal operation has been detected.");
MyStackWalker(info, my_eip);
}
else if (signo == SIGTRAP)
{
printf("\n A out of bounds array has been detected.");
MyStackWalker(info, my_eip);
}
else
{
printf("\n An unknown exception has been detected.");
MyStackWalker(info, my_eip);
}
}
int main()
{
struct sigaction newAct;
newAct.sa_sigaction= &MySignalHandler;
sigemptyset (&newAct.sa_mask);
newAct.sa_flags = SA_RESTART | SA_SIGINFO;
sigaction(SIGFPE, &newAct, NULL);
sigaction(SIGILL, &newAct, NULL);
sigaction(SIGSEGV, &newAct, NULL);
sigaction(SIGTRAP, &newAct, NULL);
}
=======================================

$ icc -V
Intel(R) C Intel(R) 64 Compiler Professional for applications running on Intel(R) 64, Version 11.0 Build 20090609 Package ID: l_cproc_p_11.0.084
Copyright (C) 1985-2009 Intel Corporation. All rights reserved.

$ icpc t2.cpp
$ g++ t2.cpp
$
]]> http://software.intel.com/en-us/forums/intel-c-compiler/topic/66465/ Thu, 02 Jul 2009 01:30:50 -0700 http://software.intel.com/en-us/forums/intel-c-compiler/topic/66465/ ISN General Re: Signal Handler on a Linux system.

Mark, one of my colleagues, fixed syntax error in your code. That makes the code works on IA-32.


================== t2.cpp for IA32 ================
#define _POSIX_SOURCE 199309

#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include <execinfo.h>
#include <setjmp.h>
#include <unistd.h>

#define __USE_GNU 1
#include <sys/ucontext.h>



void MyStackWalker (siginfo_t *info, void *my_eip)
{
void *trace[10];
int i;
int trace_size = 0;
char **messages = (char**)NULL;
trace_size = backtrace(trace, 10);
messages = backtrace_symbols(trace, trace_size);
ucontext_t *uc = (ucontext_t *)my_eip;
trace[1] = (void*)uc->uc_mcontext.gregs[REG_RIP];
for (i=0; i<trace_size; i++)
{
printf("\n[bt] %s", messages[i]);
}
free (messages);
}
void MySignalHandler (int signo, siginfo_t *info, void *my_eip)
{
if (signo == SIGFPE)
{
printf("\n A floating point exception has been detected.");
MyStackWalker(info, my_eip);
}
else if (signo == SIGSEGV)
{
printf("\n A segmentation violation has been detected.");
MyStackWalker(info, my_eip);
}
else if (signo == SIGILL)
{
printf("\n An illegal operation has been detected.");
MyStackWalker(info, my_eip);
}
else if (signo == SIGTRAP)
{
printf("\n A out of bounds array has been detected.");
MyStackWalker(info, my_eip);
}
else
{
printf("\n An unknown exception has been detected.");
MyStackWalker(info, my_eip);
}
}
int main()
{
struct sigaction newAct;
newAct.sa_sigaction= &MySignalHandler;
sigemptyset (&newAct.sa_mask);
newAct.sa_flags = SA_RESTART | SA_SIGINFO;
sigaction(SIGFPE, &newAct, NULL);
sigaction(SIGILL, &newAct, NULL);
sigaction(SIGSEGV, &newAct, NULL);
sigaction(SIGTRAP, &newAct, NULL);
}
============================================

$ icc -V
Intel(R) C Compiler Professional for applications running on IA-32, Version 11.0 Build 20090609 Package ID: l_cproc_p_11.0.084
Copyright (C) 1985-2009 Intel Corporation. All rights reserved.

$ icpc t2.cpp
$ g++ t2.cpp
$


However, above code doesn't compile on Intel 64.  Then I did some further investigation.It looks that REG_EIP only works on IA-32. In /usr/include/sys/ucontext.h, you may see something like this


#if __WORDSIZE == 64
...
enum
{
REG_R8 = 0,
# define REG_R8 REG_R8
REG_R9,
# define REG_R9 REG_R9
REG_R10,
# define REG_R10 REG_R10
REG_R11,
...
REG_RIP,
# define REG_RIP REG_RIP
...
};

#else /* __WORDSIZE == 32 */

enum
{
...
REG_EIP,
# define REG_EIP REG_EIP
REG_CS,
# define REG_CS REG_CS
REG_EFL,
# define REG_EFL REG_EFL
REG_UESP,
# define REG_UESP REG_UESP
REG_SS
# define REG_SS REG_SS
};
#endif


So, on IA-32, REG_EIP is an enum value. But on Intel 64, REG_EIP is not defined.  It seems that you should use REG_RIP instead on Intel 64.  With this modification, t2.cpp compiles.  See below.


=========== t2.cpp for Intel 64 ================
#define _POSIX_SOURCE 199309

#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include <execinfo.h>
#include <setjmp.h>
#include <unistd.h>

#define __USE_GNU 1
#include <sys/ucontext.h>



void MyStackWalker (siginfo_t *info, void *my_eip)
{
void *trace[10];
int i;
int trace_size = 0;
char **messages = (char**)NULL;
trace_size = backtrace(trace, 10);
messages = backtrace_symbols(trace, trace_size);
ucontext_t *uc = (ucontext_t *)my_eip;
trace[1] = (void*)uc->uc_mcontext.gregs[REG_RIP];
for (i=0; i<trace_size; i++)
{
printf("\n[bt] %s", messages[i]);
}
free (messages);
}
void MySignalHandler (int signo, siginfo_t *info, void *my_eip)
{
if (signo == SIGFPE)
{
printf("\n A floating point exception has been detected.");
MyStackWalker(info, my_eip);
}
else if (signo == SIGSEGV)
{
printf("\n A segmentation violation has been detected.");
MyStackWalker(info, my_eip);
}
else if (signo == SIGILL)
{
printf("\n An illegal operation has been detected.");
MyStackWalker(info, my_eip);
}
else if (signo == SIGTRAP)
{
printf("\n A out of bounds array has been detected.");
MyStackWalker(info, my_eip);
}
else
{
printf("\n An unknown exception has been detected.");
MyStackWalker(info, my_eip);
}
}
int main()
{
struct sigaction newAct;
newAct.sa_sigaction= &MySignalHandler;
sigemptyset (&newAct.sa_mask);
newAct.sa_flags = SA_RESTART | SA_SIGINFO;
sigaction(SIGFPE, &newAct, NULL);
sigaction(SIGILL, &newAct, NULL);
sigaction(SIGSEGV, &newAct, NULL);
sigaction(SIGTRAP, &newAct, NULL);
}
=======================================

$ icc -V
Intel(R) C Intel(R) 64 Compiler Professional for applications running on Intel(R) 64, Version 11.0 Build 20090609 Package ID: l_cproc_p_11.0.084
Copyright (C) 1985-2009 Intel Corporation. All rights reserved.

$ icpc t2.cpp
$ g++ t2.cpp
$


Thanks,  I just returned to work from vacation, and will try this fix This week.  I will let you know if it works on our system.
]]> http://software.intel.com/en-us/forums/intel-c-compiler/topic/66465/ Tue, 07 Jul 2009 08:11:01 -0700 http://software.intel.com/en-us/forums/intel-c-compiler/topic/66465/ ISN General