faultstatus.c revision 9bea4c13fca0e3bb4b719dcb3ed63d47d479294e 
1/*
2   Check that a fault signal handler gets the expected info
3 */
4#include <signal.h>
5#include <stdio.h>
6#include <stdlib.h>
7#include <fcntl.h>
8#include <setjmp.h>
9#include "tests/sys_mman.h"
10#include <unistd.h>
11
12/* Division by zero triggers a SIGFPE on x86 and x86_64,
13   but not on the PowerPC architecture.
14
15   On ARM-Linux, we do get a SIGFPE, but not from the faulting of a
16   division instruction (there isn't any such thing) but rather
17   because the process exits via tgkill, sending itself a SIGFPE.
18   Hence we get a SIGFPE but the SI_CODE is different from that on
19   x86/amd64-linux.
20 */
21#if defined(__powerpc__)
22#  define DIVISION_BY_ZERO_TRIGGERS_FPE 0
23#  define DIVISION_BY_ZERO_SI_CODE      SI_TKILL
24#elif defined(__arm__)
25#  define DIVISION_BY_ZERO_TRIGGERS_FPE 1
26#  define DIVISION_BY_ZERO_SI_CODE      SI_TKILL
27#else
28#  define DIVISION_BY_ZERO_TRIGGERS_FPE 1
29#  define DIVISION_BY_ZERO_SI_CODE      FPE_INTDIV
30#endif
31
32
33struct test {
34	void (*test)(void);
35	int sig;
36	int code;
37	volatile void *addr;
38};
39
40static const struct test *cur_test;
41
42static int zero();
43
44static jmp_buf escape;
45
46#define BADADDR	((int *)0x1234)
47
48#define FILESIZE	(16*1024)
49#define MAPSIZE		(2*FILESIZE)
50
51static char volatile *volatile mapping;
52
53static int testsig(int sig, int want)
54{
55	if (sig != want) {
56		fprintf(stderr, "  FAIL: expected signal %d, not %d\n", want, sig);
57		return 0;
58	}
59	return 1;
60}
61
62static int testcode(int code, int want)
63{
64	if (code != want) {
65		fprintf(stderr, "  FAIL: expected si_code==%d, not %d\n", want, code);
66		return 0;
67	}
68	return 1;
69}
70
71static int testaddr(void *addr, volatile void *want)
72{
73	if (addr != want) {
74		fprintf(stderr, "  FAIL: expected si_addr==%p, not %p\n", want, addr);
75		return 0;
76	}
77	return 1;
78
79}
80
81static void handler(int sig, siginfo_t *si, void *uc)
82{
83	int ok = 1;
84
85	ok = ok && testsig(sig, cur_test->sig);
86	ok = ok && testcode(si->si_code, cur_test->code);
87	if (cur_test->addr)
88		ok = ok && testaddr(si->si_addr, cur_test->addr);
89
90	if (ok)
91		fprintf(stderr, "  PASS\n");
92
93	siglongjmp(escape, ok + 1);
94}
95
96
97static void test1(void)
98{
99	*BADADDR = 'x';
100}
101
102static void test2()
103{
104	mapping[0] = 'x';
105}
106
107static void test3()
108{
109	mapping[FILESIZE+10];
110}
111
112static void test4()
113{
114	volatile int v = 44/zero();
115
116	(void)v;
117#if DIVISION_BY_ZERO_TRIGGERS_FPE == 0
118	raise(SIGFPE);
119#endif
120}
121
122int main()
123{
124	int fd, i;
125	static const int sigs[] = { SIGSEGV, SIGILL, SIGBUS, SIGFPE, SIGTRAP };
126	struct sigaction sa;
127
128	sa.sa_sigaction = handler;
129	sa.sa_flags = SA_SIGINFO;
130	sigfillset(&sa.sa_mask);
131
132	for(i = 0; i < sizeof(sigs)/sizeof(*sigs); i++)
133		sigaction(sigs[i], &sa, NULL);
134
135	fd = open("faultstatus.tmp", O_CREAT|O_TRUNC|O_EXCL, 0600);
136	if (fd == -1) {
137		perror("tmpfile");
138		exit(1);
139	}
140	unlink("faultstatus.tmp");
141	ftruncate(fd, FILESIZE);
142
143	mapping = mmap(0, MAPSIZE, PROT_READ, MAP_PRIVATE, fd, 0);
144	close(fd);
145
146	{
147		const struct test tests[] = {
148#define T(n, sig, code, addr) { test##n, sig, code, addr }
149			T(1, SIGSEGV,	SEGV_MAPERR,	BADADDR),
150			T(2, SIGSEGV,	SEGV_ACCERR,	mapping),
151			T(3, SIGBUS,	BUS_ADRERR,	&mapping[FILESIZE+10]),
152			T(4, SIGFPE,    DIVISION_BY_ZERO_SI_CODE, 0),
153#undef T
154		};
155
156		for(i = 0; i < sizeof(tests)/sizeof(*tests); i++) {
157			cur_test = &tests[i];
158
159			if (sigsetjmp(escape, 1) == 0) {
160				fprintf(stderr, "Test %d: ", i+1);
161				tests[i].test();
162				fprintf(stderr, "  FAIL: no fault, or handler returned\n");
163			}
164		}
165	}
166
167	return 0;
168}
169
170static int zero()
171{
172	return 0;
173}
174