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 #include "../../config.h"
  12
  13 /* Division by zero triggers a SIGFPE on x86 and x86_64,
  14    but not on the PowerPC architecture.
  15
  16    On ARM-Linux, we do get a SIGFPE, but not from the faulting of a
  17    division instruction (there isn't any such thing) but rather
  18    because the process exits via tgkill, sending itself a SIGFPE.
  19    Hence we get a SIGFPE but the SI_CODE is different from that on
  20    x86/amd64-linux.
  21  */
  22 #if defined(__powerpc__) || defined(__aarch64__)
  23 #  define DIVISION_BY_ZERO_TRIGGERS_FPE 0
  24 #if defined(VGO_freebsd)
  25 #  define DIVISION_BY_ZERO_SI_CODE      SI_LWP
  26 #else
  27 #  define DIVISION_BY_ZERO_SI_CODE      SI_TKILL
  28 #endif
  29 #elif defined(__arm__)
  30 #  define DIVISION_BY_ZERO_TRIGGERS_FPE 1
  31 #  define DIVISION_BY_ZERO_SI_CODE      SI_TKILL
  32 #else
  33 #  define DIVISION_BY_ZERO_TRIGGERS_FPE 1
  34 #  define DIVISION_BY_ZERO_SI_CODE      FPE_INTDIV
  35 #endif
  36
  37 /* Accessing non-mapped virtual address results in SIGBUS
  38  * with si_code equal to BUS_ADRERR on Linux, whereas in SIGBUS
  39  * with si_code equal to BUS_OBJERR on Solaris. On Solaris,
  40  * BUS_ADRERR is used for bus time out while BUS_OBJERR is translated
  41  * from underlying codes FC_OBJERR (x86) or ASYNC_BERR (sparc).
  42  */
  43 #if defined(VGO_solaris) || (defined(VGO_freebsd) && (FREEBSD_VERS >= FREEBSD_12_2))
  44 #  define BUS_ERROR_SI_CODE  BUS_OBJERR
  45 #else
  46 #  define BUS_ERROR_SI_CODE  BUS_ADRERR
  47 #endif
  48
  49 struct test {
  50         void (*test)(void);
  51         int sig;
  52         int code;
  53         volatile void *addr;
  54 };
  55
  56 static const struct test *cur_test;
  57
  58 static int zero();
  59
  60 static sigjmp_buf escape;
  61
  62 #define BADADDR ((int *)0x1234)
  63
  64 #define FILESIZE        (4*__pagesize)
  65 #define MAPSIZE         (2*FILESIZE)
  66 static unsigned int __pagesize;
  67 static char volatile *volatile mapping;
  68
  69 static int testsig(int sig, int want)
  70 {
  71         if (sig != want) {
  72                 fprintf(stderr, "  FAIL: expected signal %d, not %d\n", want, sig);
  73                 return 0;
  74         }
  75         return 1;
  76 }
  77
  78 static int testcode(int code, int want)
  79 {
  80         if (code != want) {
  81                 fprintf(stderr, "  FAIL: expected si_code==%d, not %d\n", want, code);
  82                 return 0;
  83         }
  84         return 1;
  85 }
  86
  87 static int testaddr(void *addr, volatile void *want)
  88 {
  89         /* Some architectures (e.g. s390) just provide enough information to
  90          resolve the page fault, but do not provide the offset within a page */
  91 #if defined(__s390__)
  92         if (addr != (void *) ((unsigned long) want & ~0xffful)) {
  93 #else
  94         if (addr != want) {
  95 #endif
  96                 fprintf(stderr, "  FAIL: expected si_addr==%p, not %p\n", want, addr);
  97                 return 0;
  98         }
  99         return 1;
 100
 101 }
 102
 103 static void handler(int sig, siginfo_t *si, void *uc)
 104 {
 105         int ok = 1;
 106
 107         ok = ok && testsig(sig, cur_test->sig);
 108         ok = ok && testcode(si->si_code, cur_test->code);
 109         if (cur_test->addr)
 110                 ok = ok && testaddr(si->si_addr, cur_test->addr);
 111
 112         if (ok)
 113                 fprintf(stderr, "  PASS\n");
 114
 115         siglongjmp(escape, ok + 1);
 116 }
 117
 118
 119 static void test1(void)
 120 {
 121         *BADADDR = 'x';
 122 }
 123
 124 static void test2()
 125 {
 126         mapping[0] = 'x';
 127 }
 128
 129 static void test3()
 130 {
 131         mapping[FILESIZE+10];
 132 }
 133
 134 static void test4()
 135 {
 136         volatile int v = 44/zero();
 137
 138         (void)v;
 139 #if DIVISION_BY_ZERO_TRIGGERS_FPE == 0
 140         raise(SIGFPE);
 141 #endif
 142 }
 143
 144 int main()
 145 {
 146         int fd, i;
 147         static const int sigs[] = { SIGSEGV, SIGILL, SIGBUS, SIGFPE, SIGTRAP };
 148         struct sigaction sa;
 149         __pagesize = (unsigned int)sysconf(_SC_PAGE_SIZE);
 150         sa.sa_sigaction = handler;
 151         sa.sa_flags = SA_SIGINFO;
 152         sigfillset(&sa.sa_mask);
 153
 154         for(i = 0; i < sizeof(sigs)/sizeof(*sigs); i++)
 155                 sigaction(sigs[i], &sa, NULL);
 156
 157         /* we need O_RDWR for the truncate below */
 158         fd = open("faultstatus.tmp", O_CREAT|O_TRUNC|O_EXCL|O_RDWR, 0600);
 159         if (fd == -1) {
 160                 perror("tmpfile");
 161                 exit(1);
 162         }
 163         unlink("faultstatus.tmp");
 164         ftruncate(fd, FILESIZE);
 165
 166         mapping = mmap(0, MAPSIZE, PROT_READ, MAP_PRIVATE, fd, 0);
 167         close(fd);
 168
 169         {
 170                 const struct test tests[] = {
 171 #define T(n, sig, code, addr) { test##n, sig, code, addr }
 172                         T(1, SIGSEGV,   SEGV_MAPERR,    BADADDR),
 173                         T(2, SIGSEGV,   SEGV_ACCERR,    mapping),
 174 #if defined(VGO_freebsd) && (FREEBSD_VERS < FREEBSD_12_2)
 175                         T(3, SIGSEGV,   BUS_ERROR_SI_CODE, &mapping[FILESIZE+10]),
 176 #else
 177                         T(3, SIGBUS,    BUS_ERROR_SI_CODE, &mapping[FILESIZE+10]),
 178 #endif
 179                         T(4, SIGFPE,    DIVISION_BY_ZERO_SI_CODE, 0),
 180 #undef T
 181                 };
 182
 183                 for(i = 0; i < sizeof(tests)/sizeof(*tests); i++) {
 184                         cur_test = &tests[i];
 185
 186                         if (sigsetjmp(escape, 1) == 0) {
 187                                 fprintf(stderr, "Test %d: ", i+1);
 188                                 tests[i].test();
 189                                 fprintf(stderr, "  FAIL: no fault, or handler returned\n");
 190                         }
 191                 }
 192         }
 193
 194         return 0;
 195 }
 196
 197 static volatile int s_zero;
 198
 199 static int zero()
 200 {
 201         return s_zero;
 202 }