none/tests/faultstatus.c

   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 /* Accessing non-mapped virtual address results in SIGBUS
  33  * with si_code equal to BUS_ADRERR on Linux, whereas in SIGBUS
  34  * with si_code equal to BUS_OBJERR on Solaris. On Solaris,
  35  * BUS_ADRERR is used for bus time out while BUS_OBJERR is translated
  36  * from underlying codes FC_OBJERR (x86) or ASYNC_BERR (sparc).
  37  */
  38 #if defined(VGO_solaris)
  39 #  define BUS_ERROR_SI_CODE  BUS_OBJERR
  40 #else
  41 #  define BUS_ERROR_SI_CODE  BUS_ADRERR
  42 #endif
  43
  44 struct test {
  45         void (*test)(void);
  46         int sig;
  47         int code;
  48         volatile void *addr;
  49 };
  50
  51 static const struct test *cur_test;
  52
  53 static int zero();
  54
  55 static sigjmp_buf escape;
  56
  57 #define BADADDR ((int *)0x1234)
  58
  59 #define FILESIZE        (4*__pagesize)
  60 #define MAPSIZE         (2*FILESIZE)
  61 static unsigned int __pagesize;
  62 static char volatile *volatile mapping;
  63
  64 static int testsig(int sig, int want)
  65 {
  66         if (sig != want) {
  67                 fprintf(stderr, "  FAIL: expected signal %d, not %d\n", want, sig);
  68                 return 0;
  69         }
  70         return 1;
  71 }
  72
  73 static int testcode(int code, int want)
  74 {
  75         if (code != want) {
  76                 fprintf(stderr, "  FAIL: expected si_code==%d, not %d\n", want, code);
  77                 return 0;
  78         }
  79         return 1;
  80 }
  81
  82 static int testaddr(void *addr, volatile void *want)
  83 {
  84         /* Some architectures (e.g. s390) just provide enough information to
  85          resolve the page fault, but do not provide the offset within a page */
  86 #if defined(__s390__)
  87         if (addr != (void *) ((unsigned long) want & ~0xffful)) {
  88 #else
  89         if (addr != want) {
  90 #endif
  91                 fprintf(stderr, "  FAIL: expected si_addr==%p, not %p\n", want, addr);
  92                 return 0;
  93         }
  94         return 1;
  95
  96 }
  97
  98 static void handler(int sig, siginfo_t *si, void *uc)
  99 {
 100         int ok = 1;
 101
 102         ok = ok && testsig(sig, cur_test->sig);
 103         ok = ok && testcode(si->si_code, cur_test->code);
 104         if (cur_test->addr)
 105                 ok = ok && testaddr(si->si_addr, cur_test->addr);
 106
 107         if (ok)
 108                 fprintf(stderr, "  PASS\n");
 109
 110         siglongjmp(escape, ok + 1);
 111 }
 112
 113
 114 static void test1(void)
 115 {
 116         *BADADDR = 'x';
 117 }
 118
 119 static void test2()
 120 {
 121         mapping[0] = 'x';
 122 }
 123
 124 static void test3()
 125 {
 126         mapping[FILESIZE+10];
 127 }
 128
 129 static void test4()
 130 {
 131         volatile int v = 44/zero();
 132
 133         (void)v;
 134 #if DIVISION_BY_ZERO_TRIGGERS_FPE == 0
 135         raise(SIGFPE);
 136 #endif
 137 }
 138
 139 int main()
 140 {
 141         int fd, i;
 142         static const int sigs[] = { SIGSEGV, SIGILL, SIGBUS, SIGFPE, SIGTRAP };
 143         struct sigaction sa;
 144         __pagesize = (unsigned int)sysconf(_SC_PAGE_SIZE);
 145         sa.sa_sigaction = handler;
 146         sa.sa_flags = SA_SIGINFO;
 147         sigfillset(&sa.sa_mask);
 148
 149         for(i = 0; i < sizeof(sigs)/sizeof(*sigs); i++)
 150                 sigaction(sigs[i], &sa, NULL);
 151
 152         /* we need O_RDWR for the truncate below */
 153         fd = open("faultstatus.tmp", O_CREAT|O_TRUNC|O_EXCL|O_RDWR, 0600);
 154         if (fd == -1) {
 155                 perror("tmpfile");
 156                 exit(1);
 157         }
 158         unlink("faultstatus.tmp");
 159         ftruncate(fd, FILESIZE);
 160
 161         mapping = mmap(0, MAPSIZE, PROT_READ, MAP_PRIVATE, fd, 0);
 162         close(fd);
 163
 164         {
 165                 const struct test tests[] = {
 166 #define T(n, sig, code, addr) { test##n, sig, code, addr }
 167                         T(1, SIGSEGV,   SEGV_MAPERR,    BADADDR),
 168                         T(2, SIGSEGV,   SEGV_ACCERR,    mapping),
 169                         T(3, SIGBUS,    BUS_ERROR_SI_CODE, &mapping[FILESIZE+10]),
 170                         T(4, SIGFPE,    DIVISION_BY_ZERO_SI_CODE, 0),
 171 #undef T
 172                 };
 173
 174                 for(i = 0; i < sizeof(tests)/sizeof(*tests); i++) {
 175                         cur_test = &tests[i];
 176
 177                         if (sigsetjmp(escape, 1) == 0) {
 178                                 fprintf(stderr, "Test %d: ", i+1);
 179                                 tests[i].test();
 180                                 fprintf(stderr, "  FAIL: no fault, or handler returned\n");
 181                         }
 182                 }
 183         }
 184
 185         return 0;
 186 }
 187
 188 static int zero()
 189 {
 190         return 0;
 191 }