MIRROR: javascript for 🐜's, a tiny runtime with big ambitions
add crash handler
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include/crash.h
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include/crash.h
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src/crash.c
+149
src/crash.c
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#include <compat.h> // IWYU pragma: keep
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#include "crash.h"
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#include <stdio.h>
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#include <stdint.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#ifndef _WIN32
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#include <signal.h>
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#define ANT_CRASH_ALT_STACK_SIZE (64 * 1024)
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#if defined(__APPLE__) || defined(__linux__) || defined(__GLIBC__)
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#define ANT_CRASH_HAVE_EXECINFO 1
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#include <execinfo.h>
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#endif
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static void as_write(int fd, const char *s) {
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size_t len = 0;
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while (s[len]) len++;
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ssize_t _ = write(fd, s, len);
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(void)_;
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}
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static void as_write_uint(int fd, unsigned long v) {
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char buf[32];
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int i = (int)sizeof(buf);
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buf[--i] = '\0';
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if (v == 0) buf[--i] = '0';
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while (v && i > 0) {
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buf[--i] = (char)('0' + (v % 10));
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v /= 10;
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}
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as_write(fd, &buf[i]);
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}
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static int install_altstack(void) {
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#ifdef SA_ONSTACK
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static void *stack_mem;
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if (stack_mem) return 1;
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stack_mem = malloc(ANT_CRASH_ALT_STACK_SIZE);
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if (!stack_mem) return 0;
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stack_t ss;
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memset(&ss, 0, sizeof(ss));
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ss.ss_sp = stack_mem;
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ss.ss_size = ANT_CRASH_ALT_STACK_SIZE;
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ss.ss_flags = 0;
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if (sigaltstack(&ss, NULL) == 0) return 1;
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free(stack_mem);
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stack_mem = NULL;
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#endif
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return 0;
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}
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static const char *signal_name(int sig) {
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switch (sig) {
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case SIGSEGV: return "SIGSEGV (invalid memory access)";
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case SIGBUS: return "SIGBUS (bus error)";
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case SIGFPE: return "SIGFPE (arithmetic exception)";
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case SIGILL: return "SIGILL (illegal instruction)";
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case SIGABRT: return "SIGABRT (abort)";
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default: return "fatal signal";
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}}
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static void crash_handler(int sig, siginfo_t *info, void *ucontext) {
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struct sigaction dfl;
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memset(&dfl, 0, sizeof(dfl));
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dfl.sa_handler = SIG_DFL;
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sigemptyset(&dfl.sa_mask);
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sigaction(sig, &dfl, NULL);
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int fd = STDERR_FILENO;
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as_write(fd, "\n=== ant crashed: ");
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as_write(fd, signal_name(sig));
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as_write(fd, " (signal ");
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as_write_uint(fd, (unsigned long)sig);
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as_write(fd, ") ===\n");
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if (info) {
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as_write(fd, " fault address: 0x");
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char hex[2 + sizeof(void *) * 2 + 1];
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int hi = (int)sizeof(hex);
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hex[--hi] = '\0';
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uintptr_t addr = (uintptr_t)info->si_addr;
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if (addr == 0) hex[--hi] = '0';
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else while (addr && hi > 0) {
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unsigned d = (unsigned)(addr & 0xF);
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hex[--hi] = (char)(d < 10 ? '0' + d : 'a' + d - 10);
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addr >>= 4;
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}
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as_write(fd, &hex[hi]);
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as_write(fd, "\n");
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}
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as_write(fd, " ant version: " ANT_VERSION "\n");
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as_write(fd, " pid: ");
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as_write_uint(fd, (unsigned long)getpid());
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as_write(fd, "\n\nNative backtrace:\n");
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#ifdef ANT_CRASH_HAVE_EXECINFO
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void *frames[64];
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int n = backtrace(frames, (int)(sizeof(frames) / sizeof(frames[0])));
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int skip = n > 2 ? 2 : 0;
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if (skip) as_write(fd, " (omitted crash_handler and signal trampoline frames)\n");
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backtrace_symbols_fd(frames + skip, n - skip, fd);
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#else
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as_write(fd, " (no execinfo support on this platform)\n");
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#endif
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as_write(fd,
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"\nPlease report this at https://github.com/themackabu/ant/issues\n"
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"Include the backtrace above and a minimal reproducer if possible.\n\n");
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raise(sig);
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}
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void ant_crash_init(void) {
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struct sigaction sa;
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memset(&sa, 0, sizeof(sa));
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sa.sa_sigaction = crash_handler;
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sa.sa_flags = SA_SIGINFO | SA_RESETHAND;
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#ifdef SA_ONSTACK
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if (install_altstack()) sa.sa_flags |= SA_ONSTACK;
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#endif
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sigemptyset(&sa.sa_mask);
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static const int sigs[] = { SIGSEGV, SIGBUS, SIGFPE, SIGILL, SIGABRT };
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for (size_t i = 0; i < sizeof(sigs) / sizeof(sigs[0]); i++) {
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sigaction(sigs[i], &sa, NULL);
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}
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}
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#else // _WIN32
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void ant_crash_init(void) {
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// TODO: SetUnhandledExceptionFilter + StackWalk64 / dbghelp
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}
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#endif
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src/main.c
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src/main.c
···
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#include "ant.h"
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#include "gc.h"
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#include "crash.h"
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#include "repl.h"
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#include "debug.h"
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#include "utils.h"
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}
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int main(int argc, char *argv[]) {
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if (!getenv("ANT_NO_CRASH_HANDLER")) ant_crash_init();
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setup_console_colors();
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parse_ant_debug_flags();
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