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* Cppcheck - A tool for static C/C++ code analysis

* 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/>.

#if defined(__CYGWIN__)

#define _BSD_SOURCE // required to have siginfo_t, SIGSTKSZ, kill(), sigaction and others

#endif

#include "signalhandler.h"

#if defined(USE_UNIX_SIGNAL_HANDLING)

#ifdef USE_UNIX_BACKTRACE_SUPPORT

#include "stacktrace.h"

#endif

#include <csignal>

#include <cstdio>

#include <cstdlib>

#include <cstring>

//#include <features.h> // __USE_DYNAMIC_STACK_SIZE

#include <map>

#include <string>

#include <sys/types.h>

#include <unistd.h>

#include <utility>

#if defined(__linux__) && defined(REG_ERR)

#include <sys/syscall.h>

#endif

#if defined(__APPLE__)

# define _XOPEN_SOURCE // ucontext.h APIs can only be used on Mac OSX >= 10.7 if _XOPEN_SOURCE is defined

# include <ucontext.h>

# undef _XOPEN_SOURCE

#elif !defined(__OpenBSD__) && !defined(__HAIKU__)

# include <ucontext.h>

#endif

// TODO: __USE_DYNAMIC_STACK_SIZE is dependent on the features.h include and not a built-in compiler define, so it might be problematic to depend on it

#ifdef __USE_DYNAMIC_STACK_SIZE

static constexpr size_t MYSTACKSIZE = (16*1024)+32768; // wild guess about a reasonable buffer

#else

static constexpr size_t MYSTACKSIZE = (16*1024)+SIGSTKSZ; // wild guess about a reasonable buffer

#endif

static char mytstack[MYSTACKSIZE]= {0}; // alternative stack for signal handler

static bool bStackBelowHeap=false; // lame attempt to locate heap vs. stack address space. See CppCheckExecutor::check_wrapper()

static FILE* signalOutput = stdout; // TODO: get rid of this

/**

* \param[in] ptr address to be examined.

* \return true if address is supposed to be on stack (contrary to heap). If ptr is 0 false will be returned.

* If unknown better return false.

static bool IsAddressOnStack(const void* ptr)

{

if (nullptr==ptr)

return false;

char a;

if (bStackBelowHeap)

return ptr < &a;

return ptr > &a;

}

/* (declare this list here, so it may be used in signal handlers in addition to main())

* A list of signals available in ISO C

* Check out http://pubs.opengroup.org/onlinepubs/009695399/basedefs/signal.h.html

* For now we only want to detect abnormal behaviour for a few selected signals:

#define DECLARE_SIGNAL(x) std::make_pair(x, #x)

using Signalmap_t = std::map<int, std::string>;

static const Signalmap_t listofsignals = {

DECLARE_SIGNAL(SIGABRT),

DECLARE_SIGNAL(SIGBUS),

DECLARE_SIGNAL(SIGFPE),

DECLARE_SIGNAL(SIGILL),

DECLARE_SIGNAL(SIGINT),

DECLARE_SIGNAL(SIGQUIT),

DECLARE_SIGNAL(SIGSEGV),

DECLARE_SIGNAL(SIGSYS),

// don't care: SIGTERM

DECLARE_SIGNAL(SIGUSR1),

//DECLARE_SIGNAL(SIGUSR2) no usage currently

};

#undef DECLARE_SIGNAL

* Entry pointer for signal handlers

* It uses functions which are not safe to be called from a signal handler,

* (http://pubs.opengroup.org/onlinepubs/9699919799/functions/V2_chap02.html#tag_15_04 has a whitelist)

* but when ending up here something went terribly wrong anyway.

* And all which is left is just printing some information and terminate.

static void CppcheckSignalHandler(int signo, siginfo_t * info, void * context) // cppcheck-suppress constParameterCallback - info can be const

{

const char* typeStr = "";

pid_t killid;

// TODO: separate these two defines

#if defined(__linux__) && defined(REG_ERR)

const auto* const uc = reinterpret_cast<const ucontext_t*>(context);

killid = static_cast<pid_t>(syscall(SYS_gettid));

if (uc) {

const int type = static_cast<int>(uc->uc_mcontext.gregs[REG_ERR]) & 2;

typeStr = (type == 0) ? "reading " : "writing ";

}

#else

(void)context;

killid = getpid();

#endif

const auto it = listofsignals.find(signo);

const char * const signame = (it==listofsignals.end()) ? "unknown" : it->second.c_str();

bool unexpectedSignal=true; // unexpected indicates program failure

bool terminate=true; // exit process/thread

const bool isAddressOnStack = IsAddressOnStack(info->si_addr);

FILE * const output = signalOutput;

switch (signo) {

case SIGABRT:

fputs("Internal error: cppcheck received signal ", output);

fputs(signame, output);

fputs(

#ifdef NDEBUG

" - abort\n",

#else

" - abort or assertion\n",

#endif

output);

break;

case SIGBUS:

fputs("Internal error: cppcheck received signal ", output);

fputs(signame, output);

switch (info->si_code) {

case BUS_ADRALN: // invalid address alignment

fputs(" - BUS_ADRALN", output);

break;

case BUS_ADRERR: // nonexistent physical address

fputs(" - BUS_ADRERR", output);

break;

case BUS_OBJERR: // object-specific hardware error

fputs(" - BUS_OBJERR", output);

break;

#ifdef BUS_MCEERR_AR

case BUS_MCEERR_AR: // Hardware memory error consumed on a machine check;

fputs(" - BUS_MCEERR_AR", output);

break;

#endif

#ifdef BUS_MCEERR_AO

case BUS_MCEERR_AO: // Hardware memory error detected in process but not consumed

fputs(" - BUS_MCEERR_AO", output);

break;

#endif

default:

break;

}

fprintf(output, " (at 0x%lx).\n",

reinterpret_cast<unsigned long>(info->si_addr));

break;

case SIGFPE:

fputs("Internal error: cppcheck received signal ", output);

fputs(signame, output);

switch (info->si_code) {

case FPE_INTDIV: // integer divide by zero

fputs(" - FPE_INTDIV", output);

break;

case FPE_INTOVF: // integer overflow

fputs(" - FPE_INTOVF", output);

break;

case FPE_FLTDIV: // floating-point divide by zero

fputs(" - FPE_FLTDIV", output);

break;

case FPE_FLTOVF: // floating-point overflow

fputs(" - FPE_FLTOVF", output);

break;

case FPE_FLTUND: // floating-point underflow

fputs(" - FPE_FLTUND", output);

break;

case FPE_FLTRES: // floating-point inexact result

fputs(" - FPE_FLTRES", output);

break;

case FPE_FLTINV: // floating-point invalid operation

fputs(" - FPE_FLTINV", output);

break;

case FPE_FLTSUB: // subscript out of range

fputs(" - FPE_FLTSUB", output);

break;

default:

break;

}

fprintf(output, " (at 0x%lx).\n",

reinterpret_cast<unsigned long>(info->si_addr));

break;

case SIGILL:

fputs("Internal error: cppcheck received signal ", output);

fputs(signame, output);

switch (info->si_code) {

case ILL_ILLOPC: // illegal opcode

fputs(" - ILL_ILLOPC", output);

break;

case ILL_ILLOPN: // illegal operand

fputs(" - ILL_ILLOPN", output);

break;

case ILL_ILLADR: // illegal addressing mode

fputs(" - ILL_ILLADR", output);

break;

case ILL_ILLTRP: // illegal trap

fputs(" - ILL_ILLTRP", output);

break;

case ILL_PRVOPC: // privileged opcode

fputs(" - ILL_PRVOPC", output);

break;

case ILL_PRVREG: // privileged register

fputs(" - ILL_PRVREG", output);

break;

case ILL_COPROC: // coprocessor error

fputs(" - ILL_COPROC", output);

break;

case ILL_BADSTK: // internal stack error

fputs(" - ILL_BADSTK", output);

break;

default:

break;

}

fprintf(output, " (at 0x%lx).%s\n",

reinterpret_cast<unsigned long>(info->si_addr),

isAddressOnStack ? " Stackoverflow?" : "");

break;

case SIGINT:

unexpectedSignal=false; // legal usage: interrupt application via CTRL-C

fputs("cppcheck received signal ", output);

fputs(signame, output);

fputs(".\n", output);

break;

case SIGSEGV:

fputs("Internal error: cppcheck received signal ", output);

fputs(signame, output);

switch (info->si_code) {

case SEGV_MAPERR: // address not mapped to object

fputs(" - SEGV_MAPERR", output);

break;

case SEGV_ACCERR: // invalid permissions for mapped object

fputs(" - SEGV_ACCERR", output);

break;

default:

break;

}

fprintf(output, " (%sat 0x%lx).%s\n",

typeStr,

reinterpret_cast<unsigned long>(info->si_addr),

isAddressOnStack ? " Stackoverflow?" : ""

);

break;

case SIGUSR1:

fputs("cppcheck received signal ", output);

fputs(signame, output);

fputs(".\n", output);

terminate=false;

break;

default:

fputs("Internal error: cppcheck received signal ", output);

fputs(signame, output);

fputs(".\n", output);

break;

}

#ifdef USE_UNIX_BACKTRACE_SUPPORT

// flush otherwise the trace might be printed earlier

fflush(output);

print_stacktrace(output, 1, true, -1, true);

#endif

if (unexpectedSignal) {

fputs("\nPlease report this to the cppcheck developers!\n", output);

}

fflush(output);

if (terminate) {

// now let things proceed, shutdown and hopefully dump core for post-mortem analysis

struct sigaction act;

memset(&act, 0, sizeof(act));

act.sa_handler=SIG_DFL;

sigaction(signo, &act, nullptr);

kill(killid, signo);

}

void register_signal_handler(FILE * const output)

{

signalOutput = output;

// determine stack vs. heap

char stackVariable;

char *heapVariable=static_cast<char*>(malloc(1));

bStackBelowHeap = &stackVariable < heapVariable;

free(heapVariable);

// set up alternative stack for signal handler

stack_t segv_stack;

segv_stack.ss_sp = mytstack;

segv_stack.ss_flags = 0;

segv_stack.ss_size = MYSTACKSIZE;

if (sigaltstack(&segv_stack, nullptr) != 0) {

// TODO: log errno

fputs("could not set alternate signal stack context.\n", output);

std::exit(EXIT_FAILURE);

}

// install signal handler

struct sigaction act;

memset(&act, 0, sizeof(act));

act.sa_flags=SA_SIGINFO|SA_ONSTACK;

act.sa_sigaction=CppcheckSignalHandler;

for (auto sig=listofsignals.cbegin(); sig!=listofsignals.cend(); ++sig) {

sigaction(sig->first, &act, nullptr);

}

#endif