From 70335deb59cc3c5d639213c04af4708901829938 Mon Sep 17 00:00:00 2001
From: Josh Gao <jmgao@google.com>
Date: Tue, 22 Mar 2016 15:10:45 -0700
Subject: [PATCH] debuggerd: set the name of the signal sender.

Bug: http://b/27925028
Change-Id: I6bff938e229d2368250d4b5c268fa24bd4badea0
(cherry picked from commit f3dde2f869801f2b5f5fb9cd9ee1a9356a0a1726)
---
 debuggerd/signal_sender.cpp | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/debuggerd/signal_sender.cpp b/debuggerd/signal_sender.cpp
index 1cfb70407..4be7e6e2b 100644
--- a/debuggerd/signal_sender.cpp
+++ b/debuggerd/signal_sender.cpp
@@ -16,6 +16,7 @@
 
 #include <errno.h>
 #include <signal.h>
+#include <stdlib.h>
 #include <string.h>
 #include <sys/socket.h>
 #include <sys/syscall.h>
@@ -35,6 +36,31 @@ struct signal_message {
   int signal;
 };
 
+static void set_signal_sender_process_name() {
+#if defined(__LP64__)
+  static constexpr char long_process_name[] = "debuggerd64:signaller";
+  static constexpr char short_process_name[] = "debuggerd64:sig";
+  static_assert(sizeof(long_process_name) <= sizeof("/system/bin/debuggerd64"), "");
+#else
+  static constexpr char long_process_name[] = "debuggerd:signaller";
+  static constexpr char short_process_name[] = "debuggerd:sig";
+  static_assert(sizeof(long_process_name) <= sizeof("/system/bin/debuggerd"), "");
+#endif
+
+  // pthread_setname_np has a maximum length of 16 chars, including null terminator.
+  static_assert(sizeof(short_process_name) <= 16, "");
+  pthread_setname_np(pthread_self(), short_process_name);
+
+  char* progname = const_cast<char*>(getprogname());
+  if (strlen(progname) <= strlen(long_process_name)) {
+    ALOGE("debuggerd: unexpected progname %s", progname);
+    return;
+  }
+
+  memset(progname, 0, strlen(progname));
+  strcpy(progname, long_process_name);
+}
+
 // Fork a process to send signals for the worker processes to use after they've dropped privileges.
 bool start_signal_sender() {
   if (signal_pid != 0) {
@@ -56,6 +82,8 @@ bool start_signal_sender() {
   } else if (fork_pid == 0) {
     close(sfd[1]);
 
+    set_signal_sender_process_name();
+
     while (true) {
       signal_message msg;
       int rc = TEMP_FAILURE_RETRY(read(sfd[0], &msg, sizeof(msg)));