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__) || defined(__aarch64__)
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
33 struct test {
34 void (*test)(void);
35 int sig;
36 int code;
37 volatile void *addr;
38 };
39
40 static const struct test *cur_test;
41
42 static int zero();
43
44 static sigjmp_buf escape;
45
46 #define BADADDR ((int *)0x1234)
47
48 #define FILESIZE (4*__pagesize)
49 #define MAPSIZE (2*FILESIZE)
50 static unsigned int __pagesize;
51 static char volatile *volatile mapping;
52
testsig(int sig,int want)53 static 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
testcode(int code,int want)62 static 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
testaddr(void * addr,volatile void * want)71 static int testaddr(void *addr, volatile void *want)
72 {
73 /* Some architectures (e.g. s390) just provide enough information to
74 resolve the page fault, but do not provide the offset within a page */
75 #if defined(__s390__)
76 if (addr != (void *) ((unsigned long) want & ~0xffful)) {
77 #else
78 if (addr != want) {
79 #endif
80 fprintf(stderr, " FAIL: expected si_addr==%p, not %p\n", want, addr);
81 return 0;
82 }
83 return 1;
84
85 }
86
87 static void handler(int sig, siginfo_t *si, void *uc)
88 {
89 int ok = 1;
90
91 ok = ok && testsig(sig, cur_test->sig);
92 ok = ok && testcode(si->si_code, cur_test->code);
93 if (cur_test->addr)
94 ok = ok && testaddr(si->si_addr, cur_test->addr);
95
96 if (ok)
97 fprintf(stderr, " PASS\n");
98
99 siglongjmp(escape, ok + 1);
100 }
101
102
103 static void test1(void)
104 {
105 *BADADDR = 'x';
106 }
107
108 static void test2()
109 {
110 mapping[0] = 'x';
111 }
112
113 static void test3()
114 {
115 mapping[FILESIZE+10];
116 }
117
118 static void test4()
119 {
120 volatile int v = 44/zero();
121
122 (void)v;
123 #if DIVISION_BY_ZERO_TRIGGERS_FPE == 0
124 raise(SIGFPE);
125 #endif
126 }
127
128 int main()
129 {
130 int fd, i;
131 static const int sigs[] = { SIGSEGV, SIGILL, SIGBUS, SIGFPE, SIGTRAP };
132 struct sigaction sa;
133 __pagesize = (unsigned int)sysconf(_SC_PAGE_SIZE);
134 sa.sa_sigaction = handler;
135 sa.sa_flags = SA_SIGINFO;
136 sigfillset(&sa.sa_mask);
137
138 for(i = 0; i < sizeof(sigs)/sizeof(*sigs); i++)
139 sigaction(sigs[i], &sa, NULL);
140
141 /* we need O_RDWR for the truncate below */
142 fd = open("faultstatus.tmp", O_CREAT|O_TRUNC|O_EXCL|O_RDWR, 0600);
143 if (fd == -1) {
144 perror("tmpfile");
145 exit(1);
146 }
147 unlink("faultstatus.tmp");
148 ftruncate(fd, FILESIZE);
149
150 mapping = mmap(0, MAPSIZE, PROT_READ, MAP_PRIVATE, fd, 0);
151 close(fd);
152
153 {
154 const struct test tests[] = {
155 #define T(n, sig, code, addr) { test##n, sig, code, addr }
156 T(1, SIGSEGV, SEGV_MAPERR, BADADDR),
157 T(2, SIGSEGV, SEGV_ACCERR, mapping),
158 T(3, SIGBUS, BUS_ADRERR, &mapping[FILESIZE+10]),
159 T(4, SIGFPE, DIVISION_BY_ZERO_SI_CODE, 0),
160 #undef T
161 };
162
163 for(i = 0; i < sizeof(tests)/sizeof(*tests); i++) {
164 cur_test = &tests[i];
165
166 if (sigsetjmp(escape, 1) == 0) {
167 fprintf(stderr, "Test %d: ", i+1);
168 tests[i].test();
169 fprintf(stderr, " FAIL: no fault, or handler returned\n");
170 }
171 }
172 }
173
174 return 0;
175 }
176
177 static int zero()
178 {
179 return 0;
180 }
181