https://github.com/JuliaLang/julia
Tip revision: 8fef8b480ef15ab60b906afe6730e952bf3c72da authored by Kristoffer Carlsson on 16 August 2018, 16:35:40 UTC
add a note on checking for equality with singletons
add a note on checking for equality with singletons
Tip revision: 8fef8b4
signal-handling.c
// This file is a part of Julia. License is MIT: https://julialang.org/license
#include <stdlib.h>
#include <stddef.h>
#include <stdio.h>
#include <inttypes.h>
#include "julia.h"
#include "julia_internal.h"
#ifndef _OS_WINDOWS_
#include <unistd.h>
#include <sys/mman.h>
#endif
#ifdef __cplusplus
extern "C" {
#endif
#include <threading.h>
// Profiler control variables //
static volatile intptr_t *bt_data_prof = NULL;
static volatile size_t bt_size_max = 0;
static volatile size_t bt_size_cur = 0;
static volatile uint64_t nsecprof = 0;
static volatile int running = 0;
static const uint64_t GIGA = 1000000000ULL;
// Timers to take samples at intervals
JL_DLLEXPORT void jl_profile_stop_timer(void);
JL_DLLEXPORT int jl_profile_start_timer(void);
static uint64_t jl_last_sigint_trigger = 0;
static uint64_t jl_disable_sigint_time = 0;
static void jl_clear_force_sigint(void)
{
jl_last_sigint_trigger = 0;
}
static int jl_check_force_sigint(void)
{
static double accum_weight = 0;
uint64_t cur_time = uv_hrtime();
uint64_t dt = cur_time - jl_last_sigint_trigger;
uint64_t last_t = jl_last_sigint_trigger;
jl_last_sigint_trigger = cur_time;
if (last_t == 0) {
accum_weight = 0;
return 0;
}
double new_weight = accum_weight * exp(-(dt / 1e9)) + 0.3;
if (!isnormal(new_weight))
new_weight = 0;
accum_weight = new_weight;
if (new_weight > 1) {
jl_disable_sigint_time = cur_time + (uint64_t)0.5e9;
return 1;
}
jl_disable_sigint_time = 0;
return 0;
}
#ifndef _OS_WINDOWS_
// Not thread local, should only be accessed by the signal handler thread.
static volatile int jl_sigint_passed = 0;
static sigset_t jl_sigint_sset;
#endif
static int jl_ignore_sigint(void)
{
// On Unix, we get the SIGINT before the debugger which makes it very
// hard to interrupt a running process in the debugger with `Ctrl-C`.
// Manually raise a `SIGINT` on current thread with the signal temporarily
// unblocked and use it's behavior to decide if we need to handle the signal.
#ifndef _OS_WINDOWS_
jl_sigint_passed = 0;
pthread_sigmask(SIG_UNBLOCK, &jl_sigint_sset, NULL);
// This can swallow an external `SIGINT` but it's not an issue
// since we don't deliver the same number of signals anyway.
pthread_kill(pthread_self(), SIGINT);
pthread_sigmask(SIG_BLOCK, &jl_sigint_sset, NULL);
if (!jl_sigint_passed)
return 1;
#endif
// Force sigint requires pressing `Ctrl-C` repeatedly.
// Ignore sigint for a short time after that to avoid rethrowing sigint too
// quickly again. (Code that has this issue is inherently racy but this is
// an interactive feature anyway.)
return jl_disable_sigint_time && jl_disable_sigint_time > uv_hrtime();
}
static int exit_on_sigint = 0;
JL_DLLEXPORT void jl_exit_on_sigint(int on)
{
exit_on_sigint = on;
}
static uintptr_t jl_get_pc_from_ctx(const void *_ctx);
void jl_show_sigill(void *_ctx);
static size_t jl_safe_read_mem(const volatile char *ptr, char *out, size_t len)
{
jl_ptls_t ptls = jl_get_ptls_states();
jl_jmp_buf *old_buf = ptls->safe_restore;
jl_jmp_buf buf;
ptls->safe_restore = &buf;
volatile size_t i = 0;
if (!jl_setjmp(buf, 0)) {
for (;i < len;i++) {
out[i] = ptr[i];
}
}
ptls->safe_restore = old_buf;
return i;
}
#if defined(_WIN32)
#include "signals-win.c"
#else
#include "signals-unix.c"
#endif
static uintptr_t jl_get_pc_from_ctx(const void *_ctx)
{
#if defined(_OS_LINUX_) && defined(_CPU_X86_64_)
return ((ucontext_t*)_ctx)->uc_mcontext.gregs[REG_RIP];
#elif defined(_OS_FREEBSD_) && defined(_CPU_X86_64_)
return ((ucontext_t*)_ctx)->uc_mcontext.mc_rip;
#elif defined(_OS_LINUX_) && defined(_CPU_X86_)
return ((ucontext_t*)_ctx)->uc_mcontext.gregs[REG_EIP];
#elif defined(_OS_FREEBSD_) && defined(_CPU_X86_)
return ((ucontext_t*)_ctx)->uc_mcontext.mc_eip;
#elif defined(_OS_DARWIN_)
return ((ucontext64_t*)_ctx)->uc_mcontext64->__ss.__rip;
#elif defined(_OS_WINDOWS_) && defined(_CPU_X86_)
return ((CONTEXT*)_ctx)->Eip;
#elif defined(_OS_WINDOWS_) && defined(_CPU_X86_64_)
return ((CONTEXT*)_ctx)->Rip;
#elif defined(_OS_LINUX_) && defined(_CPU_AARCH64_)
return ((ucontext_t*)_ctx)->uc_mcontext.pc;
#elif defined(_OS_LINUX_) && defined(_CPU_ARM_)
return ((ucontext_t*)_ctx)->uc_mcontext.arm_pc;
#else
// TODO for PPC
return 0;
#endif
}
void jl_show_sigill(void *_ctx)
{
char *pc = (char*)jl_get_pc_from_ctx(_ctx);
// unsupported platform
if (!pc)
return;
#if defined(_CPU_X86_64_) || defined(_CPU_X86_)
uint8_t inst[15]; // max length of x86 instruction
size_t len = jl_safe_read_mem(pc, (char*)inst, sizeof(inst));
// ud2
if (len >= 2 && inst[0] == 0x0f && inst[1] == 0x0b) {
jl_safe_printf("Unreachable reached at %p\n", (void*)pc);
}
else {
jl_safe_printf("Invalid instruction at %p: ", (void*)pc);
for (int i = 0;i < len;i++) {
if (i == 0) {
jl_safe_printf("0x%02" PRIx8, inst[i]);
}
else {
jl_safe_printf(", 0x%02" PRIx8, inst[i]);
}
}
jl_safe_printf("\n");
}
#elif defined(_OS_LINUX_) && defined(_CPU_AARCH64_)
uint32_t inst = 0;
size_t len = jl_safe_read_mem(pc, (char*)&inst, 4);
if (len < 4)
jl_safe_printf("Fault when reading instruction: %d bytes read\n", (int)len);
if (inst == 0xd4200020) { // brk #0x1
// The signal might actually be SIGTRAP instead, doesn't hurt to handle it here though.
jl_safe_printf("Unreachable reached at %p\n", pc);
}
else {
jl_safe_printf("Invalid instruction at %p: 0x%08" PRIx32 "\n", pc, inst);
}
#elif defined(_OS_LINUX_) && defined(_CPU_ARM_)
ucontext_t *ctx = (ucontext_t*)_ctx;
if (ctx->uc_mcontext.arm_cpsr & (1 << 5)) {
// Thumb
uint16_t inst[2] = {0, 0};
size_t len = jl_safe_read_mem(pc, (char*)&inst, 4);
if (len < 2)
jl_safe_printf("Fault when reading Thumb instruction: %d bytes read\n", (int)len);
// LLVM and GCC uses different code for the trap...
if (inst[0] == 0xdefe || inst[0] == 0xdeff) {
// The signal might actually be SIGTRAP instead, doesn't hurt to handle it here though.
jl_safe_printf("Unreachable reached in Thumb mode at %p: 0x%04" PRIx16 "\n",
(void*)pc, inst[0]);
}
else {
jl_safe_printf("Invalid Thumb instruction at %p: 0x%04" PRIx16 ", 0x%04" PRIx16 "\n",
(void*)pc, inst[0], inst[1]);
}
}
else {
uint32_t inst = 0;
size_t len = jl_safe_read_mem(pc, (char*)&inst, 4);
if (len < 4)
jl_safe_printf("Fault when reading instruction: %d bytes read\n", (int)len);
// LLVM and GCC uses different code for the trap...
if (inst == 0xe7ffdefe || inst == 0xe7f000f0) {
// The signal might actually be SIGTRAP instead, doesn't hurt to handle it here though.
jl_safe_printf("Unreachable reached in ARM mode at %p: 0x%08" PRIx32 "\n",
(void*)pc, inst);
}
else {
jl_safe_printf("Invalid ARM instruction at %p: 0x%08" PRIx32 "\n", (void*)pc, inst);
}
}
#else
// TODO for PPC
(void)_ctx;
#endif
}
// what to do on a critical error
void jl_critical_error(int sig, bt_context_t *context, uintptr_t *bt_data, size_t *bt_size)
{
// This function is not allowed to reference any TLS variables.
// We need to explicitly pass in the TLS buffer pointer when
// we make `jl_filename` and `jl_lineno` thread local.
size_t i, n = *bt_size;
if (sig)
jl_safe_printf("\nsignal (%d): %s\n", sig, strsignal(sig));
jl_safe_printf("in expression starting at %s:%d\n", jl_filename, jl_lineno);
if (context)
*bt_size = n = rec_backtrace_ctx(bt_data, JL_MAX_BT_SIZE, context);
for (i = 0; i < n; i++)
jl_gdblookup(bt_data[i] - 1);
gc_debug_print_status();
gc_debug_critical_error();
}
///////////////////////
// Utility functions //
///////////////////////
JL_DLLEXPORT int jl_profile_init(size_t maxsize, uint64_t delay_nsec)
{
bt_size_max = maxsize;
nsecprof = delay_nsec;
if (bt_data_prof != NULL)
free((void*)bt_data_prof);
bt_data_prof = (intptr_t*) calloc(maxsize, sizeof(intptr_t));
if (bt_data_prof == NULL && maxsize > 0)
return -1;
bt_size_cur = 0;
return 0;
}
JL_DLLEXPORT uint8_t *jl_profile_get_data(void)
{
return (uint8_t*) bt_data_prof;
}
JL_DLLEXPORT size_t jl_profile_len_data(void)
{
return bt_size_cur;
}
JL_DLLEXPORT size_t jl_profile_maxlen_data(void)
{
return bt_size_max;
}
JL_DLLEXPORT uint64_t jl_profile_delay_nsec(void)
{
return nsecprof;
}
JL_DLLEXPORT void jl_profile_clear_data(void)
{
bt_size_cur = 0;
}
JL_DLLEXPORT int jl_profile_is_running(void)
{
return running;
}
#ifdef __cplusplus
}
#endif