/* 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]; size_t 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), "%u", 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,SIGNAL_CAST 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) { progname = pname; } #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 #ifdef SIGFPE CatchSignal(SIGFPE,SIGNAL_CAST sig_fault); #endif } /** 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; }