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// Copyright 2015 The Go Authors. All rights reserved. // Use of this source code is governed by a BSD-style // license that can be found in the LICENSE file.
// Test that a signal handler that uses up stack space does not crash // if the signal is delivered to a thread running a goroutine. // This is a lot like ../testcarchive/main2.c.
#include <setjmp.h> #include <signal.h> #include <stddef.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <sys/types.h> #include <unistd.h> #include <sched.h> #include <time.h> #include <dlfcn.h>
static void die(const char* msg) { perror(msg); exit(EXIT_FAILURE); }
static volatile sig_atomic_t sigioSeen;
// Use up some stack space. static void recur(int i, char *p) { char a[1024];
*p = '\0'; if (i > 0) { recur(i - 1, a); } }
// Signal handler that uses up more stack space than a goroutine will have. static void ioHandler(int signo, siginfo_t* info, void* ctxt) { char a[1024];
recur(4, a); sigioSeen = 1; }
static jmp_buf jmp; static char* nullPointer;
// Signal handler for SIGSEGV on a C thread. static void segvHandler(int signo, siginfo_t* info, void* ctxt) { sigset_t mask; int i;
if (sigemptyset(&mask) < 0) { die("sigemptyset"); } if (sigaddset(&mask, SIGSEGV) < 0) { die("sigaddset"); } i = sigprocmask(SIG_UNBLOCK, &mask, NULL); if (i != 0) { fprintf(stderr, "sigprocmask: %s\n", strerror(i)); exit(EXIT_FAILURE); }
// Don't try this at home. longjmp(jmp, signo);
// We should never get here. abort(); }
int main(int argc, char** argv) { int verbose; struct sigaction sa; void* handle; void (*fn)(void); sigset_t mask; int i; struct timespec ts;
verbose = argc > 2; setvbuf(stdout, NULL, _IONBF, 0);
// Call setsid so that we can use kill(0, SIGIO) below. // Don't check the return value so that this works both from // a job control shell and from a shell script. setsid();
if (verbose) { printf("calling sigaction\n"); }
memset(&sa, 0, sizeof sa); sa.sa_sigaction = ioHandler; if (sigemptyset(&sa.sa_mask) < 0) { die("sigemptyset"); } sa.sa_flags = SA_SIGINFO; if (sigaction(SIGIO, &sa, NULL) < 0) { die("sigaction"); }
sa.sa_sigaction = segvHandler; if (sigaction(SIGSEGV, &sa, NULL) < 0 || sigaction(SIGBUS, &sa, NULL) < 0) { die("sigaction"); }
if (verbose) { printf("calling dlopen\n"); }
handle = dlopen(argv[1], RTLD_NOW | RTLD_GLOBAL); if (handle == NULL) { fprintf(stderr, "%s\n", dlerror()); exit(EXIT_FAILURE); }
if (verbose) { printf("calling dlsym\n"); }
// Start some goroutines. fn = (void(*)(void))dlsym(handle, "RunGoroutines"); if (fn == NULL) { fprintf(stderr, "%s\n", dlerror()); exit(EXIT_FAILURE); }
if (verbose) { printf("calling RunGoroutines\n"); }
fn();
// Block SIGIO in this thread to make it more likely that it // will be delivered to a goroutine.
if (verbose) { printf("calling pthread_sigmask\n"); }
if (sigemptyset(&mask) < 0) { die("sigemptyset"); } if (sigaddset(&mask, SIGIO) < 0) { die("sigaddset"); } i = pthread_sigmask(SIG_BLOCK, &mask, NULL); if (i != 0) { fprintf(stderr, "pthread_sigmask: %s\n", strerror(i)); exit(EXIT_FAILURE); }
if (verbose) { printf("calling kill\n"); }
if (kill(0, SIGIO) < 0) { die("kill"); }
if (verbose) { printf("waiting for sigioSeen\n"); }
// Wait until the signal has been delivered. i = 0; while (!sigioSeen) { ts.tv_sec = 0; ts.tv_nsec = 1000000; nanosleep(&ts, NULL); i++; if (i > 5000) { fprintf(stderr, "looping too long waiting for signal\n"); exit(EXIT_FAILURE); } }
if (verbose) { printf("calling setjmp\n"); }
// Test that a SIGSEGV on this thread is delivered to us. if (setjmp(jmp) == 0) { if (verbose) { printf("triggering SIGSEGV\n"); }
*nullPointer = '\0';
fprintf(stderr, "continued after address error\n"); exit(EXIT_FAILURE); }
if (verbose) { printf("calling dlsym\n"); }
// Make sure that a SIGSEGV in Go causes a run-time panic. fn = (void (*)(void))dlsym(handle, "TestSEGV"); if (fn == NULL) { fprintf(stderr, "%s\n", dlerror()); exit(EXIT_FAILURE); }
if (verbose) { printf("calling TestSEGV\n"); }
fn();
printf("PASS\n"); return 0; }
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