1 // Copyright 2015 The Go Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style
3 // license that can be found in the LICENSE file.
4
5 // Test that a signal handler that uses up stack space does not crash
6 // if the signal is delivered to a thread running a goroutine.
7 // This is a lot like misc/cgo/testcarchive/main2.c.
8
9 #include <setjmp.h>
10 #include <signal.h>
11 #include <stddef.h>
12 #include <stdio.h>
13 #include <stdlib.h>
14 #include <string.h>
15 #include <sys/types.h>
16 #include <unistd.h>
17 #include <sched.h>
18 #include <time.h>
19 #include <dlfcn.h>
20
21 static void die(const char* msg) {
22 perror(msg);
23 exit(EXIT_FAILURE);
24 }
25
26 static volatile sig_atomic_t sigioSeen;
27
28 // Use up some stack space.
29 static void recur(int i, char *p) {
30 char a[1024];
31
32 *p = '\0';
33 if (i > 0) {
34 recur(i - 1, a);
35 }
36 }
37
38 // Signal handler that uses up more stack space than a goroutine will have.
39 static void ioHandler(int signo, siginfo_t* info, void* ctxt) {
40 char a[1024];
41
42 recur(4, a);
43 sigioSeen = 1;
44 }
45
46 static jmp_buf jmp;
47 static char* nullPointer;
48
49 // Signal handler for SIGSEGV on a C thread.
50 static void segvHandler(int signo, siginfo_t* info, void* ctxt) {
51 sigset_t mask;
52 int i;
53
54 if (sigemptyset(&mask) < 0) {
55 die("sigemptyset");
56 }
57 if (sigaddset(&mask, SIGSEGV) < 0) {
58 die("sigaddset");
59 }
60 i = sigprocmask(SIG_UNBLOCK, &mask, NULL);
61 if (i != 0) {
62 fprintf(stderr, "sigprocmask: %s\n", strerror(i));
63 exit(EXIT_FAILURE);
64 }
65
66 // Don't try this at home.
67 longjmp(jmp, signo);
68
69 // We should never get here.
70 abort();
71 }
72
73 int main(int argc, char** argv) {
74 int verbose;
75 struct sigaction sa;
76 void* handle;
77 void (*fn)(void);
78 sigset_t mask;
79 int i;
80 struct timespec ts;
81
82 verbose = argc > 2;
83 setvbuf(stdout, NULL, _IONBF, 0);
84
85 // Call setsid so that we can use kill(0, SIGIO) below.
86 // Don't check the return value so that this works both from
87 // a job control shell and from a shell script.
88 setsid();
89
90 if (verbose) {
91 printf("calling sigaction\n");
92 }
93
94 memset(&sa, 0, sizeof sa);
95 sa.sa_sigaction = ioHandler;
96 if (sigemptyset(&sa.sa_mask) < 0) {
97 die("sigemptyset");
98 }
99 sa.sa_flags = SA_SIGINFO;
100 if (sigaction(SIGIO, &sa, NULL) < 0) {
101 die("sigaction");
102 }
103
104 sa.sa_sigaction = segvHandler;
105 if (sigaction(SIGSEGV, &sa, NULL) < 0 || sigaction(SIGBUS, &sa, NULL) < 0) {
106 die("sigaction");
107 }
108
109 if (verbose) {
110 printf("calling dlopen\n");
111 }
112
113 handle = dlopen(argv[1], RTLD_NOW | RTLD_GLOBAL);
114 if (handle == NULL) {
115 fprintf(stderr, "%s\n", dlerror());
116 exit(EXIT_FAILURE);
117 }
118
119 if (verbose) {
120 printf("calling dlsym\n");
121 }
122
123 // Start some goroutines.
124 fn = (void(*)(void))dlsym(handle, "RunGoroutines");
125 if (fn == NULL) {
126 fprintf(stderr, "%s\n", dlerror());
127 exit(EXIT_FAILURE);
128 }
129
130 if (verbose) {
131 printf("calling RunGoroutines\n");
132 }
133
134 fn();
135
136 // Block SIGIO in this thread to make it more likely that it
137 // will be delivered to a goroutine.
138
139 if (verbose) {
140 printf("calling pthread_sigmask\n");
141 }
142
143 if (sigemptyset(&mask) < 0) {
144 die("sigemptyset");
145 }
146 if (sigaddset(&mask, SIGIO) < 0) {
147 die("sigaddset");
148 }
149 i = pthread_sigmask(SIG_BLOCK, &mask, NULL);
150 if (i != 0) {
151 fprintf(stderr, "pthread_sigmask: %s\n", strerror(i));
152 exit(EXIT_FAILURE);
153 }
154
155 if (verbose) {
156 printf("calling kill\n");
157 }
158
159 if (kill(0, SIGIO) < 0) {
160 die("kill");
161 }
162
163 if (verbose) {
164 printf("waiting for sigioSeen\n");
165 }
166
167 // Wait until the signal has been delivered.
168 i = 0;
169 while (!sigioSeen) {
170 ts.tv_sec = 0;
171 ts.tv_nsec = 1000000;
172 nanosleep(&ts, NULL);
173 i++;
174 if (i > 5000) {
175 fprintf(stderr, "looping too long waiting for signal\n");
176 exit(EXIT_FAILURE);
177 }
178 }
179
180 if (verbose) {
181 printf("calling setjmp\n");
182 }
183
184 // Test that a SIGSEGV on this thread is delivered to us.
185 if (setjmp(jmp) == 0) {
186 if (verbose) {
187 printf("triggering SIGSEGV\n");
188 }
189
190 *nullPointer = '\0';
191
192 fprintf(stderr, "continued after address error\n");
193 exit(EXIT_FAILURE);
194 }
195
196 if (verbose) {
197 printf("calling dlsym\n");
198 }
199
200 // Make sure that a SIGSEGV in Go causes a run-time panic.
201 fn = (void (*)(void))dlsym(handle, "TestSEGV");
202 if (fn == NULL) {
203 fprintf(stderr, "%s\n", dlerror());
204 exit(EXIT_FAILURE);
205 }
206
207 if (verbose) {
208 printf("calling TestSEGV\n");
209 }
210
211 fn();
212
213 printf("PASS\n");
214 return 0;
215 }