DO NOT MERGE: debuggerd: verify that traced threads belong to the right process.
Fix two races in debuggerd's PTRACE_ATTACH logic:
1. The target thread in a crash dump request could exit between the
/proc/<pid>/task/<tid> check and the PTRACE_ATTACH.
2. Sibling threads could exit between listing /proc/<pid>/task and the
PTRACE_ATTACH.
Backport of NYC change I4dfe1ea30e2c211d2389321bd66e3684dd757591
Bug: http://b/29555636
Change-Id: I6c6efcf82a49bca140d761b2d1de04215ba4d252
diff --git a/debuggerd/utility.h b/debuggerd/utility.h
index 263374d..e8ec7ef 100644
--- a/debuggerd/utility.h
+++ b/debuggerd/utility.h
@@ -79,4 +79,9 @@
void dump_memory(log_t* log, Backtrace* backtrace, uintptr_t addr, const char* fmt, ...);
+bool pid_contains_tid(pid_t pid, pid_t tid);
+
+// Attach to a thread, and verify that it's still a member of the given process
+bool ptrace_attach_thread(pid_t pid, pid_t tid);
+
#endif // _DEBUGGERD_UTILITY_H