daemon/sigsegv.c

   1 /* -*- Mode: C ; c-basic-offset: 2 -*- */
   2 /*
   3  * LADI Session Handler (ladish)
   4  *
   5  * Copyright (C) 2005 - 2008 Jaco Kroon <jaco@kroon.co.za>
   6  *
   7  **************************************************************************
   8  * This file contains code to print out a stack-trace when program segfaults.
   9  **************************************************************************
  10  *
  11  * LADI Session Handler is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License as published by
  13  * the Free Software Foundation; either version 2 of the License, or
  14  * (at your option) any later version.
  15  *
  16  * LADI Session Handler is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19  * GNU General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU General Public License
  22  * along with LADI Session Handler. If not, see <http://www.gnu.org/licenses/>
  23  * or write to the Free Software Foundation, Inc.,
  24  * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  25  */
  26
  27 #include "config.h"
  28
  29 #define NO_CPP_DEMANGLE
  30 #define SIGSEGV_NO_AUTO_INIT
  31
  32 #ifndef _GNU_SOURCE
  33 # define _GNU_SOURCE
  34 #endif
  35
  36 #include <memory.h>
  37 #include <stdlib.h>
  38 #include <stdio.h>
  39 #include <signal.h>
  40 #include <ucontext.h>
  41 #include <dlfcn.h>
  42 #include <execinfo.h>
  43 #include <errno.h>
  44 #ifndef NO_CPP_DEMANGLE
  45 //#include <cxxabi.h>
  46 char * __cxa_demangle(const char * __mangled_name, char * __output_buffer, size_t * __length, int * __status);
  47 #endif
  48
  49 #include "../log.h"
  50
  51 #if defined(REG_RIP)
  52 # define SIGSEGV_STACK_IA64
  53 # define REGFORMAT "%016lx"
  54 #elif defined(REG_EIP)
  55 # define SIGSEGV_STACK_X86
  56 # define REGFORMAT "%08x"
  57 #else
  58 # define SIGSEGV_STACK_GENERIC
  59 # define REGFORMAT "%x"
  60 #endif
  61
  62 #if defined(__arm__) || defined(__powerpc__) || defined (__ia64__) || defined (__alpha__) || defined (__FreeBSD_kernel__) || defined (__sh__)
  63 # define DISABLE_STACKTRACE
  64 #endif
  65
  66 static void signal_segv(int signum, siginfo_t* info, void*ptr) {
  67     static const char *si_codes[3] = {"", "SEGV_MAPERR", "SEGV_ACCERR"};
  68
  69 #if !defined(DISABLE_STACKTRACE)
  70     size_t i;
  71     ucontext_t *ucontext = (ucontext_t*)ptr;
  72
  73 #if defined(SIGSEGV_STACK_X86) || defined(SIGSEGV_STACK_IA64)
  74     int f = 0;
  75     Dl_info dlinfo;
  76     void **bp = 0;
  77     void *ip = 0;
  78 #else
  79     void *bt[20];
  80     char **strings;
  81     size_t sz;
  82 #endif
  83 #endif
  84
  85     if (signum == SIGSEGV)
  86     {
  87         log_error("Segmentation Fault!");
  88     }
  89     else if (signum == SIGABRT)
  90     {
  91         log_error("Abort!");
  92     }
  93     else if (signum == SIGILL)
  94     {
  95         log_error("Illegal instruction!");
  96     }
  97     else if (signum == SIGFPE)
  98     {
  99         log_error("Floating point exception!");
 100     }
 101     else
 102     {
 103         log_error("Unknown bad signal catched!");
 104     }
 105
 106     log_error("info.si_signo = %d", signum);
 107     log_error("info.si_errno = %d", info->si_errno);
 108     log_error("info.si_code  = %d (%s)", info->si_code, si_codes[info->si_code]);
 109     log_error("info.si_addr  = %p", info->si_addr);
 110 #if defined(DISABLE_STACKTRACE)
 111     log_error("No stack trace");
 112 #else
 113     for(i = 0; i < NGREG; i++)
 114     {
 115       log_error("reg[%02d]       = 0x" REGFORMAT, (int)i, ucontext->uc_mcontext.gregs[i]);
 116     }
 117
 118 #if defined(SIGSEGV_STACK_X86) || defined(SIGSEGV_STACK_IA64)
 119 # if defined(SIGSEGV_STACK_IA64)
 120     ip = (void*)ucontext->uc_mcontext.gregs[REG_RIP];
 121     bp = (void**)ucontext->uc_mcontext.gregs[REG_RBP];
 122 # elif defined(SIGSEGV_STACK_X86)
 123     ip = (void*)ucontext->uc_mcontext.gregs[REG_EIP];
 124     bp = (void**)ucontext->uc_mcontext.gregs[REG_EBP];
 125 # endif
 126
 127     log_error("Stack trace:");
 128     while(bp && ip) {
 129         if(!dladdr(ip, &dlinfo))
 130             break;
 131
 132         const char *symname = dlinfo.dli_sname;
 133 #ifndef NO_CPP_DEMANGLE
 134         int status;
 135         char *tmp = __cxa_demangle(symname, NULL, 0, &status);
 136
 137         if(status == 0 && tmp)
 138             symname = tmp;
 139 #endif
 140
 141         log_error("% 2d: %p <%s+%u> (%s)",
 142                 ++f,
 143                 ip,
 144                 symname,
 145                 (unsigned)(ip - dlinfo.dli_saddr),
 146                 dlinfo.dli_fname);
 147
 148 #ifndef NO_CPP_DEMANGLE
 149         if(tmp)
 150             free(tmp);
 151 #endif
 152
 153         if(dlinfo.dli_sname && !strcmp(dlinfo.dli_sname, "main"))
 154             break;
 155
 156         ip = bp[1];
 157         bp = (void**)bp[0];
 158     }
 159 #else
 160     log_error("Stack trace (non-dedicated):");
 161     sz = backtrace(bt, 20);
 162     strings = backtrace_symbols(bt, sz);
 163
 164     for(i = 0; i < sz; ++i)
 165         log_error("%s", strings[i]);
 166 #endif
 167     log_error("End of stack trace");
 168 #endif
 169     exit (-1);
 170 }
 171
 172 int setup_sigsegv() {
 173     struct sigaction action;
 174
 175     memset(&action, 0, sizeof(action));
 176     action.sa_sigaction = signal_segv;
 177     action.sa_flags = SA_SIGINFO;
 178     if(sigaction(SIGSEGV, &action, NULL) < 0) {
 179         log_error("sigaction failed. errno is %d (%s)", errno, strerror(errno));
 180         return 0;
 181     }
 182
 183     if(sigaction(SIGILL, &action, NULL) < 0) {
 184         log_error("sigaction failed. errno is %d (%s)", errno, strerror(errno));
 185         return 0;
 186     }
 187
 188     if(sigaction(SIGABRT, &action, NULL) < 0) {
 189         log_error("sigaction failed. errno is %d (%s)", errno, strerror(errno));
 190         return 0;
 191     }
 192
 193     if(sigaction(SIGFPE, &action, NULL) < 0) {
 194         log_error("sigaction failed. errno is %d (%s)", errno, strerror(errno));
 195         return 0;
 196     }
 197
 198     return 1;
 199 }
 200
 201 #ifndef SIGSEGV_NO_AUTO_INIT
 202 static void __attribute((constructor)) init(void) {
 203     setup_sigsegv();
 204 }
 205 #endif