runtime/tracer: passthrough unexpected signals by default

misc/test_runner/include/ia2_test_runner.h

@@ -23,12 +23,13 @@ struct fake_criterion_test {
   ia2_test_fn test;
   ia2_test_fn init;
   int exit_code;
+  int signal;
 };
 
 extern struct fake_criterion_test *fake_criterion_tests;
 
-#define _STRINGIFY(a) #a
-#define STRINGIFY(a) _STRINGIFY(a)
+#define STRINGIFY(a) #a
+#define EXPAND_AND_STRINGIFY(a) STRINGIFY(a)
 
 /*
  * Placing IA2_{BEGIN,END}_NO_WRAP between the function declaration stops the rewriter from creating a
@@ -42,8 +43,8 @@ extern struct fake_criterion_test *fake_criterion_tests;
   IA2_END_NO_WRAP                                                                           \
   struct fake_criterion_test fake_criterion_##suite_##_##name_##_##test IA2_SHARED_DATA = { \
       .next = NULL,                                                                         \
-      .suite = STRINGIFY(suite_),                                                           \
-      .name = STRINGIFY(name_),                                                             \
+      .suite = EXPAND_AND_STRINGIFY(suite_),                                                           \
+      .name = EXPAND_AND_STRINGIFY(name_),                                                             \
       .test = fake_criterion_##suite_##_##name_,                                            \
       ##__VA_ARGS__};                                                                       \
   __attribute__((constructor)) void fake_criterion_add_##suite_##_##name_##_##test(void) {  \

misc/test_runner/test_runner.c

@@ -94,6 +94,12 @@ int main() {
       fprintf(stderr, " (%s)", STRINGIFY(EXIT_FAILURE));
     } else if (exit_code > 128) {
       fprintf(stderr, " (SIG%s)", sigabbrev_np(exit_code - 128));
+    } else if (test_info->signal != 0) {
+      // Sometimes the signal doesn't show up with `WIFSIGNALED`, so we check the exit status as well.
+      fprintf(stderr, " (SIG%s)", sigabbrev_np(test_info->signal));
+    }
+    if (test_info->signal != 0) {
+      fprintf(stderr, ", signal (SIG%s)", sigabbrev_np(test_info->signal));
     }
     fprintf(stderr, "...\n");
 
@@ -118,12 +124,14 @@ int main() {
       perror("waitpid");
       return 2;
     }
-    if WIFSIGNALED (stat) {
+    if (WIFSIGNALED(stat) && WTERMSIG(stat) != test_info->signal) {
       fprintf(stderr, "forked test child was terminated by signal %d\n", WTERMSIG(stat));
       return 1;
     }
     int exit_status = WEXITSTATUS(stat);
-    if (exit_status != test_info->exit_code) {
+    if (exit_status != test_info->exit_code ||
+        // Sometimes the signal doesn't show up with `WIFSIGNALED`, so we check the exit status as well.
+        (exit_status > 128 && exit_status - 128 == test_info->signal)) {
       fprintf(stderr, "forked test child exited with status %d, but %d was expected\n", exit_status, test_info->exit_code);
       return 1;
     }

runtime/tracer/track_memory_map.c

@@ -471,15 +471,24 @@ enum wait_trap_result {
   WAIT_PTRACE_FORK,
   WAIT_EXEC,
   WAIT_CONT,
-};
-
-/* wait for the next trap from the inferior.
 
-returns the wait_trap_result corresponding to the event.
+  // Passthrough ptrace the stopped signal.
+  // This is the default cause.
+  WAIT_PASSTHROUGH_SIGNAL,
+};
 
-if the exit is WAIT_EXITED, the exit status will be placed in *exit_status_out
-if it is non-NULL. */
-static enum wait_trap_result wait_for_next_trap(pid_t pid, pid_t *pid_out, int *exit_status_out) {
+/**
+ * Wait for the next trap from the inferior.
+ *
+ * Returns the `wait_trap_result` corresponding to the event.
+ *
+ * If the exit is `WAIT_EXITED`, the exit status will be placed
+ * in `*exit_status_out` if it is non-NULL.
+ *
+ * If the exit is `WAIT_PASSTHROUGH_SIGNAL`, the signal will be placed
+ * in `*passthrough_signal` if it is non-NULL.
+ */
+static enum wait_trap_result wait_for_next_trap(pid_t pid, pid_t *pid_out, int *exit_status_out, int *passthrough_signal) {
   bool entry = (pid == -1);
   int stat = 0;
   static pid_t last_pid = 0; /* used to limit logs to when pid changes */
@@ -556,8 +565,11 @@ static enum wait_trap_result wait_for_next_trap(pid_t pid, pid_t *pid_out, int *
       debug_event("child stopped by sigsegv\n");
       return WAIT_SIGSEGV;
     default:
-      fprintf(stderr, "child stopped by unexpected signal %d\n", WSTOPSIG(stat));
-      return WAIT_ERROR;
+      debug_event("child stopped by unexpected signal %d\n", WSTOPSIG(stat));
+      if (passthrough_signal) {
+        *passthrough_signal = WSTOPSIG(stat);
+      }
+      return WAIT_PASSTHROUGH_SIGNAL;
     }
   }
   fprintf(stderr, "unknown wait status %x\n", stat);
@@ -716,7 +728,8 @@ bool track_memory_map(pid_t pid, int *exit_status_out, enum trace_mode mode) {
   while (true) {
     /* wait for the process to get signalled */
     pid_t waited_pid = pid;
-    enum wait_trap_result wait_result = wait_for_next_trap(-1, &waited_pid, exit_status_out);
+    int passthrough_signal = 0;
+    enum wait_trap_result wait_result = wait_for_next_trap(-1, &waited_pid, exit_status_out, &passthrough_signal);
     switch (wait_result) {
     /* we need to handle events relating to process lifetime upfront: these
     include clone()/fork()/exec() and sigchld */
@@ -745,6 +758,12 @@ bool track_memory_map(pid_t pid, int *exit_status_out, enum trace_mode mode) {
       }
       continue;
       break;
+    case WAIT_PASSTHROUGH_SIGNAL:
+      if (ptrace(continue_request, waited_pid, 0, passthrough_signal) < 0) {
+        perror("could not PTRACE_SYSCALL...");
+      }
+      continue;
+      break;
     case WAIT_GROUP_STOP:
       printf("group stop in syscall entry\n");
       if (ptrace(PTRACE_LISTEN, waited_pid, 0, 0) < 0) {
@@ -817,7 +836,7 @@ bool track_memory_map(pid_t pid, int *exit_status_out, enum trace_mode mode) {
     case WAIT_SIGNALED: {
       fprintf(stderr, "process received fatal signal (syscall entry)\n");
       enum control_flow cf = handle_process_exit(&maps, waited_pid);
-      return false;
+      return true;
     }
     case WAIT_EXITED: {
       debug_exit("pid %d exited (syscall entry)\n", waited_pid);
@@ -888,7 +907,7 @@ bool track_memory_map(pid_t pid, int *exit_status_out, enum trace_mode mode) {
       if (ptrace(PTRACE_SYSCALL, waited_pid, 0, 0) < 0) {
         perror("could not PTRACE_SYSCALL");
       }
-      switch (wait_for_next_trap(waited_pid, NULL, exit_status_out)) {
+      switch (wait_for_next_trap(waited_pid, NULL, exit_status_out, NULL)) {
       case WAIT_SYSCALL:
         break;
       case WAIT_ERROR:
@@ -922,7 +941,7 @@ bool track_memory_map(pid_t pid, int *exit_status_out, enum trace_mode mode) {
     if (ptrace(PTRACE_SYSCALL, waited_pid, 0, 0) < 0) {
       perror("could not PTRACE_SYSCALL");
     }
-    switch (wait_for_next_trap(waited_pid, NULL, exit_status_out)) {
+    switch (wait_for_next_trap(waited_pid, NULL, exit_status_out, NULL)) {
     case WAIT_STOP:
       break;
     case WAIT_SYSCALL:

tests/post_condition/dav1d.c

@@ -24,8 +24,6 @@ void dav1d_get_picture_post_condition(Dav1dContext *const c, Dav1dPicture *const
   cr_log_info("dav1d_get_picture post condition ran");
   if (out->stride[0] < 0) {
     cr_log_info("negative stride");
-    // signals, like the `SIGABRT` from `assert` don't yet work with
-    // `ia2-sandbox` and its `ptrace` tracer.
-    exit(128 + SIGABRT);
   }
+  assert(out->stride[0] > 0);
 }

tests/post_condition/main.c

@@ -21,7 +21,7 @@ Test(post_condition, normal) {
   dav1d_get_picture(&c, &pic);
 }
 
-Test(post_condition, corrupt_bounds, .exit_code = 128 + SIGABRT) {
+Test(post_condition, corrupt_bounds, .signal = SIGABRT) {
   corrupt_stride = true;
   dav1d_get_picture(&c, &pic);
 }