source: branches/samba-3.3.x/source/lib/fault.c

/* 
   Unix SMB/CIFS implementation.
   Critical Fault handling
   Copyright (C) Andrew Tridgell 1992-1998
   
   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.
   
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.
   
   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

#include "includes.h"

#ifdef HAVE_SYS_PRCTL_H
#include <sys/prctl.h>
#endif

static void (*cont_fn)(void *);
static char *corepath;

/*******************************************************************
report a fault
********************************************************************/
static void fault_report(int sig)
{
        static int counter;

        if (counter) _exit(1);

        counter++;

        DEBUGSEP(0);
        DEBUG(0,("INTERNAL ERROR: Signal %d in pid %d (%s)",sig,(int)sys_getpid(),SAMBA_VERSION_STRING));
        DEBUG(0,("\nPlease read the Trouble-Shooting section of the Samba3-HOWTO\n"));
        DEBUG(0,("\nFrom: http://www.samba.org/samba/docs/Samba3-HOWTO.pdf\n"));
        DEBUGSEP(0);
  
        smb_panic("internal error");

        if (cont_fn) {
                cont_fn(NULL);
#ifndef __OS2__ /* don't use the built in signal capture stuff - prefer native handling of errors */
#ifdef SIGSEGV
                CatchSignal(SIGSEGV,SIGNAL_CAST SIG_DFL);
#endif
#ifdef SIGBUS
                CatchSignal(SIGBUS,SIGNAL_CAST SIG_DFL);
#endif
#ifdef SIGABRT
                CatchSignal(SIGABRT,SIGNAL_CAST SIG_DFL);
#endif
#endif /* __OS2__ */
                return; /* this should cause a core dump */
        }
        exit(1);
}

/****************************************************************************
catch serious errors
****************************************************************************/
static void sig_fault(int sig)
{
        fault_report(sig);
}

/*******************************************************************
setup our fault handlers
********************************************************************/
void fault_setup(void (*fn)(void *))
{
        cont_fn = fn;

#ifndef __OS2__ /* don't use the built in signal capture stuff - prefer native handling of errors */
#ifdef SIGSEGV
        CatchSignal(SIGSEGV,SIGNAL_CAST sig_fault);
#endif
#ifdef SIGBUS
        CatchSignal(SIGBUS,SIGNAL_CAST sig_fault);
#endif
#ifdef SIGABRT
        CatchSignal(SIGABRT,SIGNAL_CAST sig_fault);
#endif
#endif /* __OS2__ */
}

/*******************************************************************
make all the preparations to safely dump a core file
********************************************************************/

void dump_core_setup(const char *progname)
{
        char *logbase = NULL;
        char *end = NULL;

        if (lp_logfile() && *lp_logfile()) {
                if (asprintf(&logbase, "%s", lp_logfile()) < 0) {
                        return;
                }
                if ((end = strrchr_m(logbase, '/'))) {
                        *end = '\0';
                }
        } else {
                /* We will end up here is the log file is given on the command
                 * line by the -l option but the "log file" option is not set
                 * in smb.conf.
                 */
                if (asprintf(&logbase, "%s", get_dyn_LOGFILEBASE()) < 0) {
                        return;
                }
        }

        SMB_ASSERT(progname != NULL);

        if (asprintf(&corepath, "%s/cores", logbase) < 0) {
                SAFE_FREE(logbase);
                return;
        }
        if (mkdir(corepath,0700) == -1) {
                if (errno != EEXIST) {
                        SAFE_FREE(corepath);
                        SAFE_FREE(logbase);
                        return;
                }
        }
        if (chmod(corepath,0700) == -1) {
                SAFE_FREE(corepath);
                SAFE_FREE(logbase);
                return;
        }

        SAFE_FREE(corepath);
        if (asprintf(&corepath, "%s/cores/%s",
                        logbase, progname) < 0) {
                SAFE_FREE(logbase);
                return;
        }
        if (mkdir(corepath,0700) == -1) {
                if (errno != EEXIST) {
                        SAFE_FREE(corepath);
                        SAFE_FREE(logbase);
                        return;
                }
        }

        if (sys_chown(corepath,getuid(),getgid()) == -1) {
                SAFE_FREE(corepath);
                SAFE_FREE(logbase);
                return;
        }
        if (chmod(corepath,0700) == -1) {
                SAFE_FREE(corepath);
                SAFE_FREE(logbase);
                return;
        }

        SAFE_FREE(logbase);

#ifdef HAVE_GETRLIMIT
#ifdef RLIMIT_CORE
        {
                struct rlimit rlp;
                getrlimit(RLIMIT_CORE, &rlp);
                rlp.rlim_cur = MAX(16*1024*1024,rlp.rlim_cur);
                setrlimit(RLIMIT_CORE, &rlp);
                getrlimit(RLIMIT_CORE, &rlp);
                DEBUG(3,("Maximum core file size limits now %d(soft) %d(hard)\n",
                         (int)rlp.rlim_cur,(int)rlp.rlim_max));
        }
#endif
#endif

#if defined(HAVE_PRCTL) && defined(PR_SET_DUMPABLE)
        /* On Linux we lose the ability to dump core when we change our user
         * ID. We know how to dump core safely, so let's make sure we have our
         * dumpable flag set.
         */
        prctl(PR_SET_DUMPABLE, 1);
#endif

        /* FIXME: if we have a core-plus-pid facility, configurably set
         * this up here.
         */
}

 void dump_core(void)
{
        static bool called;

        if (called) {
                DEBUG(0, ("dump_core() called recursive\n"));
                exit(1);
        }
        called = true;

        /* Note that even if core dumping has been disabled, we still set up
         * the core path. This is to handle the case where core dumping is
         * turned on in smb.conf and the relevant daemon is not restarted.
         */
        if (!lp_enable_core_files()) {
                DEBUG(0, ("Exiting on internal error (core file administratively disabled)\n"));
                exit(1);
        }

#if DUMP_CORE
        /* If we're running as non root we might not be able to dump the core
         * file to the corepath.  There must not be an unbecome_root() before
         * we call abort(). */
        if (geteuid() != 0) {
                become_root();
        }

        if (corepath == NULL) {
                DEBUG(0, ("Can not dump core: corepath not set up\n"));
                exit(1);
        }

        if (*corepath != '\0') {
                /* The chdir might fail if we dump core before we finish
                 * processing the config file.
                 */
                if (chdir(corepath) != 0) {
                        DEBUG(0, ("unable to change to %s\n", corepath));
                        DEBUGADD(0, ("refusing to dump core\n"));
                        exit(1);
                }

                DEBUG(0,("dumping core in %s\n", corepath));
        }

        umask(~(0700));
        dbgflush();

        /* Ensure we don't have a signal handler for abort. */
#ifdef SIGABRT
        CatchSignal(SIGABRT,SIGNAL_CAST SIG_DFL);
#endif

        abort();

#else /* DUMP_CORE */
        exit(1);
#endif /* DUMP_CORE */
}