corefiles

[mats.lindberg at se.transport.bombardier.com]

Hi All

When I try to catch SIGTERM and generate a core file the call stack is corrupted on FreeBSD.

Yes I know that I do not have to catch the signal, a core is generated by default. But the reason is that I need to do more at SIGTERM.

Example 1

In gdb backtrace, why is monitorSignalHandlerBUS listed? it is never called!

test1.c
--------- cut here -------

#include <stdio.h>
#include <signal.h>

static void
monitorSignalHandlerBUS(int signo)
{
        printf("monitorSignalHandlerBUS\n");
        fflush(stdout);
}
static void
monitorSignalHandlerTERM(int signo)
{
        printf("monitorSignalHandlerTERM\n");
        fflush(stdout);
        abort();
}

int
main(int argc, char **argv)
{

        signal(SIGBUS, monitorSignalHandlerBUS);
        signal(SIGTERM, monitorSignalHandlerTERM);

        kill(getpid(), SIGTERM);
}

--------- cut here -------


is compiled on FreeBSD
>cc -g test1.c -o test1

>./test1
monitorSignalHandlerTERM
Abort (core dumped)

>gdb test1 test1.core
GNU gdb 6.1.1 [FreeBSD]
Copyright 2004 Free Software Foundation, Inc.
GDB is free software, covered by the GNU General Public License, and you are
welcome to change it and/or distribute copies of it under certain conditions.
Type "show copying" to see the conditions.
There is absolutely no warranty for GDB.  Type "show warranty" for details.
This GDB was configured as "i386-marcel-freebsd"...
Core was generated by `test1'.
Program terminated with signal 6, Aborted.
Reading symbols from /lib/libc.so.5...done.
Loaded symbols for /lib/libc.so.5
Reading symbols from /libexec/ld-elf.so.1...done.
Loaded symbols for /libexec/ld-elf.so.1
#0  0x280c237b in kill () from /lib/libc.so.5
(gdb) bt
#0  0x280c237b in kill () from /lib/libc.so.5
#1  0x280b7422 in raise () from /lib/libc.so.5
#2  0x28129c1b in abort () from /lib/libc.so.5
#3  0x080486a8 in monitorSignalHandlerTERM (signo=15) at test1.c:15
#4  0xbfbfff94 in ?? ()
#5  0x0000000f in ?? ()
#6  0x00000000 in ?? ()
#7  0xbfbfe9d0 in ?? ()
#8  0x00000002 in ?? ()
#9  0x0804867c in monitorSignalHandlerBUS () at test1.c:9
#10 0x080485a5 in _start ()
#11 0x00000001 in ?? ()
(gdb)

Example 2

In gdb backtrace, what is frame_dummy ?

test2.c
--------- cut here -------

#include <signal.h>

static void
SignalHandler(int signo)
{
        abort();
}

int
main(int argc, char **argv)
{

        signal(SIGTERM, SignalHandler);

        kill(getpid(), SIGTERM);
}

--------- cut here -------


is compiled on FreeBSD
>cc -g test2.c -o test2

>./test2

Abort (core dumped)

>gdb test2 test2.core
GNU gdb 6.1.1 [FreeBSD]
Copyright 2004 Free Software Foundation, Inc.
GDB is free software, covered by the GNU General Public License, and you are
welcome to change it and/or distribute copies of it under certain conditions.
Type "show copying" to see the conditions.
There is absolutely no warranty for GDB.  Type "show warranty" for details.
This GDB was configured as "i386-marcel-freebsd"...
Core was generated by `test2'.
Program terminated with signal 6, Aborted.
Reading symbols from /lib/libc.so.5...done.
Loaded symbols for /lib/libc.so.5
Reading symbols from /libexec/ld-elf.so.1...done.
Loaded symbols for /libexec/ld-elf.so.1
#0  0x280c237b in kill () from /lib/libc.so.5
(gdb) bt
#0  0x280c237b in kill () from /lib/libc.so.5
#1  0x280b7422 in raise () from /lib/libc.so.5
#2  0x28129c1b in abort () from /lib/libc.so.5
#3  0x080485cf in SignalHandler (signo=15) at test2.c:6
#4  0xbfbfff94 in ?? ()
#5  0x0000000f in ?? ()
#6  0x00000000 in ?? ()
#7  0xbfbfe9d0 in ?? ()
#8  0x00000002 in ?? ()
#9  0x080485c4 in frame_dummy ()
#10 0x08048519 in _start ()
#11 0x00000001 in ?? ()
(gdb)


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