debuggerd: fix several bugs caused by fork/setuid change.

Previously, we weren't PTRACE_ATTACHing to all of the threads of a
process, and we were also trying to do it after forking and dropping
privileges. This patch ensures that all ptrace attaching/detaching
happens in one place, before forking/exiting respectively.

Bug: http://b/26443860
Bug: http://b/26436605
Bug: http://b/26436486
Change-Id: Id94e0c1d9d56c051d0dd281d895aaa3285079198
diff --git a/debuggerd/tombstone.h b/debuggerd/tombstone.h
index 5f2d239..2b8b8be 100644
--- a/debuggerd/tombstone.h
+++ b/debuggerd/tombstone.h
@@ -20,6 +20,7 @@
 #include <stdbool.h>
 #include <stddef.h>
 #include <sys/types.h>
+#include <set>
 #include <string>
 
 class BacktraceMap;
@@ -30,10 +31,9 @@
  */
 int open_tombstone(std::string* path);
 
-/* Creates a tombstone file and writes the crash dump to it.
- * Returns the path of the tombstone, which must be freed using free(). */
-void engrave_tombstone(int tombstone_fd, BacktraceMap* map, pid_t pid, pid_t tid, int signal,
-                       int original_si_code, uintptr_t abort_msg_address, bool dump_sibling_threads,
-                       bool* detach_failed, int* total_sleep_time_usec);
+/* Creates a tombstone file and writes the crash dump to it. */
+void engrave_tombstone(int tombstone_fd, BacktraceMap* map, pid_t pid, pid_t tid,
+                       const std::set<pid_t>& siblings, int signal, int original_si_code,
+                       uintptr_t abort_msg_address);
 
 #endif // _DEBUGGERD_TOMBSTONE_H