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/*
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"
#include "version.h"
#include "system/wait.h"
#include "system/filesys.h"
/**
* @file
* @brief Fault handling
*/
/* the registered fault handler */
static struct {
const char *name;
void (*fault_handler)(int sig);
} fault_handlers;
static const char *progname;
#ifdef HAVE_BACKTRACE
#include <execinfo.h>
#elif HAVE_LIBEXC_H
#include <libexc.h>
#endif
/**
* Write backtrace to debug log
*/
_PUBLIC_ void call_backtrace(void)
{
#ifdef HAVE_BACKTRACE
#ifndef BACKTRACE_STACK_SIZE
#define BACKTRACE_STACK_SIZE 64
#endif
void *backtrace_stack[BACKTRACE_STACK_SIZE];
int backtrace_size;
char **backtrace_strings;
/* get the backtrace (stack frames) */
backtrace_size = backtrace(backtrace_stack,BACKTRACE_STACK_SIZE);
backtrace_strings = backtrace_symbols(backtrace_stack, backtrace_size);
DEBUG(0, ("BACKTRACE: %lu stack frames:\n",
(unsigned long)backtrace_size));
if (backtrace_strings) {
int i;
for (i = 0; i < backtrace_size; i++)
DEBUGADD(0, (" #%u %s\n", i, backtrace_strings[i]));
/* Leak the backtrace_strings, rather than risk what free() might do */
}
#elif HAVE_LIBEXC
#define NAMESIZE 32 /* Arbitrary */
#ifndef BACKTRACE_STACK_SIZE
#define BACKTRACE_STACK_SIZE 64
#endif
/* The IRIX libexc library provides an API for unwinding the stack. See
* libexc(3) for details. Apparantly trace_back_stack leaks memory, but
* since we are about to abort anyway, it hardly matters.
*
* Note that if we paniced due to a SIGSEGV or SIGBUS (or similar) this
* will fail with a nasty message upon failing to open the /proc entry.
*/
{
uint64_t addrs[BACKTRACE_STACK_SIZE];
char * names[BACKTRACE_STACK_SIZE];
char namebuf[BACKTRACE_STACK_SIZE * NAMESIZE];
int i;
int levels;
ZERO_ARRAY(addrs);
ZERO_ARRAY(names);
ZERO_ARRAY(namebuf);
for (i = 0; i < BACKTRACE_STACK_SIZE; i++) {
names[i] = namebuf + (i * NAMESIZE);
}
levels = trace_back_stack(0, addrs, names,
BACKTRACE_STACK_SIZE, NAMESIZE);
DEBUG(0, ("BACKTRACE: %d stack frames:\n", levels));
for (i = 0; i < levels; i++) {
DEBUGADD(0, (" #%d 0x%llx %s\n", i, addrs[i], names[i]));
}
}
#undef NAMESIZE
#endif
}
_PUBLIC_ const char *panic_action = NULL;
/**
Something really nasty happened - panic !
**/
_PUBLIC_ _NORETURN_ void smb_panic(const char *why)
{
int result;
if (panic_action && *panic_action) {
char pidstr[20];
char cmdstring[200];
safe_strcpy(cmdstring, panic_action, sizeof(cmdstring));
snprintf(pidstr, sizeof(pidstr), "%d", (int) getpid());
all_string_sub(cmdstring, "%PID%", pidstr, sizeof(cmdstring));
if (progname) {
all_string_sub(cmdstring, "%PROG%", progname, sizeof(cmdstring));
}
DEBUG(0, ("smb_panic(): calling panic action [%s]\n", cmdstring));
result = system(cmdstring);
if (result == -1)
DEBUG(0, ("smb_panic(): fork failed in panic action: %s\n",
strerror(errno)));
else
DEBUG(0, ("smb_panic(): action returned status %d\n",
WEXITSTATUS(result)));
}
DEBUG(0,("PANIC: %s\n", why));
call_backtrace();
#ifdef SIGABRT
CatchSignal(SIGABRT, SIG_DFL);
#endif
abort();
}
/**
report a fault
**/
_NORETURN_ static void fault_report(int sig)
{
static int counter;
if (counter) _exit(1);
DEBUG(0,("=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=\n"));
DEBUG(0,("INTERNAL ERROR: Signal %d in pid %d (%s)",sig,(int)getpid(),SAMBA_VERSION_STRING));
DEBUG(0,("\nPlease read the file BUGS.txt in the distribution\n"));
DEBUG(0,("=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=\n"));
smb_panic("internal error");
exit(1);
}
/**
catch serious errors
**/
_NORETURN_ static void sig_fault(int sig)
{
if (fault_handlers.fault_handler) {
/* we have a fault handler, call it. It may not return. */
fault_handlers.fault_handler(sig);
}
/* If it returns or doesn't exist, use regular reporter */
fault_report(sig);
}
/**
setup our fault handlers
**/
_PUBLIC_ void fault_setup(const char *pname)
{
if (progname != NULL) {
return;
}
progname = pname;
#ifdef SIGSEGV
CatchSignal(SIGSEGV, sig_fault);
#endif
#ifdef SIGBUS
CatchSignal(SIGBUS, sig_fault);
#endif
#ifdef SIGABRT
CatchSignal(SIGABRT, sig_fault);
#endif
#ifdef SIGFPE
CatchSignal(SIGFPE, sig_fault);
#endif
}
/**
disable setting up fault handlers
**/
_PUBLIC_ void fault_setup_disable(void)
{
progname = "fault disabled";
}
/**
register a fault handler.
Should only be called once in the execution of smbd.
*/
_PUBLIC_ bool register_fault_handler(const char *name,
void (*fault_handler)(int sig))
{
if (fault_handlers.name != NULL) {
/* it's already registered! */
DEBUG(2,("fault handler '%s' already registered - failed '%s'\n",
fault_handlers.name, name));
return false;
}
fault_handlers.name = name;
fault_handlers.fault_handler = fault_handler;
DEBUG(2,("fault handler '%s' registered\n", name));
return true;
}
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