compiler-rt/test/dfsan/conditional_callbacks_sig.c

   1 // RUN: %clang_dfsan -fno-sanitize=dataflow -O2 -fPIE -DCALLBACKS -c %s -o %t-callbacks.o
   2 // RUN: %clang_dfsan -fsanitize-ignorelist=%S/Inputs/flags_abilist.txt -O2 -mllvm -dfsan-conditional-callbacks %s %t-callbacks.o -o %t
   3 // RUN: %run %t FooBarBaz 2>&1 | FileCheck %s
   4
   5 #include <assert.h>
   6 #include <sanitizer/dfsan_interface.h>
   7 #include <signal.h>
   8 #include <stdio.h>
   9 #include <string.h>
  10 #include <sys/types.h>
  11 #include <unistd.h>
  12
  13 #ifdef CALLBACKS
  14 // Compile this code without DFSan to avoid recursive instrumentation.
  15
  16 void my_dfsan_conditional_callback(dfsan_label Label, dfsan_origin Origin) {
  17   assert(Label != 0);
  18   assert(Origin == 0);
  19
  20   static int Count = 0;
  21   switch (Count++) {
  22   case 0:
  23     assert(Label == 1);
  24     break;
  25   case 1:
  26     assert(Label == 4);
  27     break;
  28   default:
  29     break;
  30   }
  31
  32   fprintf(stderr, "Label %u used as condition\n", Label);
  33 }
  34
  35 #else
  36 // Compile this code with DFSan and -dfsan-conditional-callbacks to insert the
  37 // callbacks.
  38
  39 extern void my_dfsan_conditional_callback(dfsan_label Label,
  40                                           dfsan_origin Origin);
  41
  42 volatile int x = 0;
  43 volatile int y = 1;
  44 volatile int z = 0;
  45
  46 void SignalHandler(int signo) {
  47   assert(dfsan_get_label(x) == 0);
  48   assert(dfsan_get_label(y) != 0);
  49   assert(dfsan_get_label(z) != 0);
  50   // Running the conditional callback from a signal handler is risky,
  51   // because the code must be written with signal handler context in mind.
  52   // Instead dfsan_get_labels_in_signal_conditional() will indicate labels
  53   // used in conditions inside signal handlers.
  54   // CHECK-NOT: Label 8 used as condition
  55   if (z != 0) {
  56     x = y;
  57   }
  58 }
  59
  60 int main(int Argc, char *Argv[]) {
  61   assert(Argc >= 1);
  62   int unknown = (Argv[0][0] != 0) ? 1 : 0;
  63   dfsan_set_label(1, &unknown, sizeof(unknown));
  64
  65   dfsan_set_conditional_callback(my_dfsan_conditional_callback);
  66
  67   // CHECK: Label 1 used as condition
  68   if (unknown) {
  69     z = 42;
  70   }
  71
  72   assert(dfsan_get_labels_in_signal_conditional() == 0);
  73   dfsan_set_label(4, (void *)&y, sizeof(y));
  74   dfsan_set_label(8, (void *)&z, sizeof(z));
  75
  76   struct sigaction sa = {};
  77   sa.sa_handler = SignalHandler;
  78   int r = sigaction(SIGHUP, &sa, NULL);
  79   assert(dfsan_get_label(r) == 0);
  80
  81   kill(getpid(), SIGHUP);
  82   signal(SIGHUP, SIG_DFL);
  83
  84   assert(dfsan_get_labels_in_signal_conditional() == 8);
  85   assert(x == 1);
  86   // CHECK: Label 4 used as condition
  87   if (x != 0) {
  88     z = 123;
  89   }
  90   // Flush should clear the conditional signals seen.
  91   dfsan_flush();
  92   assert(dfsan_get_labels_in_signal_conditional() == 0);
  93   return 0;
  94 }
  95
  96 #endif // #ifdef CALLBACKS