crash_dump: clear the signal mask.

crash_dump inherits its signal mask from the thread that forked it,
which always has all of its signals blocked, now that sigchain respects
sa_mask.

Manually clear the signal mask, and reduce the timeout to a
still-generous 2 seconds.

Bug: http://b/38427757
Test: manually inserted sleep in crash_dump
Merged-In: If1c9adb68777b71fb19d9b0f47d6998733ed8f52
Change-Id: If1c9adb68777b71fb19d9b0f47d6998733ed8f52
(cherry picked from commit e740250b9d966c7eb9a7959a47526906780d7715)

1 files changed, 7 insertions, 1 deletions

diff --git a/debuggerd/crash_dump.cpp b/debuggerd/crash_dump.cpp
index 88f390b0e..1027f69cd 100644
--- a/debuggerd/crash_dump.cpp
+++ b/debuggerd/crash_dump.cpp
@@ -212,6 +212,12 @@ int main(int argc, char** argv) {
     return 1;
   }
 
+  sigset_t mask;
+  sigemptyset(&mask);
+  if (sigprocmask(SIG_SETMASK, &mask, nullptr) != 0) {
+    PLOG(FATAL) << "failed to set signal mask";
+  }
+
   pid_t main_tid;
   pid_t pseudothread_tid;
 
@@ -259,7 +265,7 @@ int main(int argc, char** argv) {
   }
 
   // Die if we take too long.
-  alarm(20);
+  alarm(2);
 
   std::string attach_error;