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 static void signal_segv(int signum, siginfo_t* info, void*ptr) {
  63     static const char *si_codes[3] = {"", "SEGV_MAPERR", "SEGV_ACCERR"};
  64
  65     size_t i;
  66     ucontext_t *ucontext = (ucontext_t*)ptr;
  67
  68 #if defined(SIGSEGV_STACK_X86) || defined(SIGSEGV_STACK_IA64)
  69     int f = 0;
  70     Dl_info dlinfo;
  71     void **bp = 0;
  72     void *ip = 0;
  73 #else
  74     void *bt[20];
  75     char **strings;
  76     size_t sz;
  77 #endif
  78
  79     if (signum == SIGSEGV)
  80     {
  81         log_error("Segmentation Fault!");
  82     }
  83     else if (signum == SIGABRT)
  84     {
  85         log_error("Abort!");
  86     }
  87     else if (signum == SIGILL)
  88     {
  89         log_error("Illegal instruction!");
  90     }
  91     else if (signum == SIGFPE)
  92     {
  93         log_error("Floating point exception!");
  94     }
  95     else
  96     {
  97         log_error("Unknown bad signal catched!");
  98     }
  99
 100     log_error("info.si_signo = %d", signum);
 101     log_error("info.si_errno = %d", info->si_errno);
 102     log_error("info.si_code  = %d (%s)", info->si_code, si_codes[info->si_code]);
 103     log_error("info.si_addr  = %p", info->si_addr);
 104     for(i = 0; i < NGREG; i++)
 105         log_error("reg[%02d]       = 0x" REGFORMAT, i, ucontext->uc_mcontext.gregs[i]);
 106
 107 #if defined(SIGSEGV_STACK_X86) || defined(SIGSEGV_STACK_IA64)
 108 # if defined(SIGSEGV_STACK_IA64)
 109     ip = (void*)ucontext->uc_mcontext.gregs[REG_RIP];
 110     bp = (void**)ucontext->uc_mcontext.gregs[REG_RBP];
 111 # elif defined(SIGSEGV_STACK_X86)
 112     ip = (void*)ucontext->uc_mcontext.gregs[REG_EIP];
 113     bp = (void**)ucontext->uc_mcontext.gregs[REG_EBP];
 114 # endif
 115
 116     log_error("Stack trace:");
 117     while(bp && ip) {
 118         if(!dladdr(ip, &dlinfo))
 119             break;
 120
 121         const char *symname = dlinfo.dli_sname;
 122 #ifndef NO_CPP_DEMANGLE
 123         int status;
 124         char *tmp = __cxa_demangle(symname, NULL, 0, &status);
 125
 126         if(status == 0 && tmp)
 127             symname = tmp;
 128 #endif
 129
 130         log_error("% 2d: %p <%s+%u> (%s)",
 131                 ++f,
 132                 ip,
 133                 symname,
 134                 (unsigned)(ip - dlinfo.dli_saddr),
 135                 dlinfo.dli_fname);
 136
 137 #ifndef NO_CPP_DEMANGLE
 138         if(tmp)
 139             free(tmp);
 140 #endif
 141
 142         if(dlinfo.dli_sname && !strcmp(dlinfo.dli_sname, "main"))
 143             break;
 144
 145         ip = bp[1];
 146         bp = (void**)bp[0];
 147     }
 148 #else
 149     log_error("Stack trace (non-dedicated):");
 150     sz = backtrace(bt, 20);
 151     strings = backtrace_symbols(bt, sz);
 152
 153     for(i = 0; i < sz; ++i)
 154         log_error("%s", strings[i]);
 155 #endif
 156     log_error("End of stack trace");
 157     exit (-1);
 158 }
 159
 160 int setup_sigsegv() {
 161     struct sigaction action;
 162
 163     memset(&action, 0, sizeof(action));
 164     action.sa_sigaction = signal_segv;
 165     action.sa_flags = SA_SIGINFO;
 166     if(sigaction(SIGSEGV, &action, NULL) < 0) {
 167         log_error("sigaction failed. errno is %d (%s)", errno, strerror(errno));
 168         return 0;
 169     }
 170
 171     if(sigaction(SIGILL, &action, NULL) < 0) {
 172         log_error("sigaction failed. errno is %d (%s)", errno, strerror(errno));
 173         return 0;
 174     }
 175
 176     if(sigaction(SIGABRT, &action, NULL) < 0) {
 177         log_error("sigaction failed. errno is %d (%s)", errno, strerror(errno));
 178         return 0;
 179     }
 180
 181     if(sigaction(SIGFPE, &action, NULL) < 0) {
 182         log_error("sigaction failed. errno is %d (%s)", errno, strerror(errno));
 183         return 0;
 184     }
 185
 186     return 1;
 187 }
 188
 189 #ifndef SIGSEGV_NO_AUTO_INIT
 190 static void __attribute((constructor)) init(void) {
 191     setup_sigsegv();
 192 }
 193 #endif