From f5a960a187ba8959596f6a324c2b5a05c1be9b35 Mon Sep 17 00:00:00 2001
From: Josh Gao <jmgao@google.com>
Date: Wed, 10 Aug 2016 17:57:01 -0700
Subject: [PATCH] debuggerd: remove useless timeout from wait_for_signal.

The watchdog already handles things for us, so the timeout logic in
wait_for_signal is pointless.

Change-Id: Id81ad5f294068216b73e04c4e2ceca072ae1bbc0
---
 debuggerd/debuggerd.cpp |  5 +++--
 debuggerd/utility.cpp   | 15 ++-------------
 debuggerd/utility.h     |  2 +-
 3 files changed, 6 insertions(+), 16 deletions(-)

diff --git a/debuggerd/debuggerd.cpp b/debuggerd/debuggerd.cpp
index a82fd079e..0c18b9c58 100644
--- a/debuggerd/debuggerd.cpp
+++ b/debuggerd/debuggerd.cpp
@@ -459,9 +459,10 @@ static bool perform_dump(const debugger_request_t& request, int fd, int tombston
     return false;
   }
 
-  int total_sleep_time_usec = 0;
   while (true) {
-    int signal = wait_for_signal(request.tid, &total_sleep_time_usec);
+    // wait_for_signal waits for forever, but the watchdog process will kill us
+    // if it takes too long.
+    int signal = wait_for_signal(request.tid);
     switch (signal) {
       case -1:
         ALOGE("debuggerd: timed out waiting for signal");
diff --git a/debuggerd/utility.cpp b/debuggerd/utility.cpp
index bd060954e..7fabf690b 100644
--- a/debuggerd/utility.cpp
+++ b/debuggerd/utility.cpp
@@ -31,9 +31,6 @@
 #include <backtrace/Backtrace.h>
 #include <log/log.h>
 
-constexpr int SLEEP_TIME_USEC = 50000;          // 0.05 seconds
-constexpr int MAX_TOTAL_SLEEP_USEC = 10000000;  // 10 seconds
-
 // Whitelist output desired in the logcat output.
 bool is_allowed_in_logcat(enum logtype ltype) {
   if ((ltype == HEADER)
@@ -74,10 +71,10 @@ void _LOG(log_t* log, enum logtype ltype, const char* fmt, ...) {
   }
 }
 
-int wait_for_signal(pid_t tid, int* total_sleep_time_usec) {
+int wait_for_signal(pid_t tid) {
   while (true) {
     int status;
-    pid_t n = TEMP_FAILURE_RETRY(waitpid(tid, &status, __WALL | WNOHANG));
+    pid_t n = TEMP_FAILURE_RETRY(waitpid(tid, &status, __WALL));
     if (n == -1) {
       ALOGE("waitpid failed: tid %d, %s", tid, strerror(errno));
       return -1;
@@ -91,14 +88,6 @@ int wait_for_signal(pid_t tid, int* total_sleep_time_usec) {
         return -1;
       }
     }
-
-    if (*total_sleep_time_usec > MAX_TOTAL_SLEEP_USEC) {
-      ALOGE("timed out waiting for stop signal: tid=%d", tid);
-      return -1;
-    }
-
-    usleep(SLEEP_TIME_USEC);
-    *total_sleep_time_usec += SLEEP_TIME_USEC;
   }
 }
 
diff --git a/debuggerd/utility.h b/debuggerd/utility.h
index cd01188c3..d820f0f91 100644
--- a/debuggerd/utility.h
+++ b/debuggerd/utility.h
@@ -77,7 +77,7 @@ enum logtype {
 void _LOG(log_t* log, logtype ltype, const char *fmt, ...)
         __attribute__ ((format(printf, 3, 4)));
 
-int wait_for_signal(pid_t tid, int* total_sleep_time_usec);
+int wait_for_signal(pid_t tid);
 
 void dump_memory(log_t* log, Backtrace* backtrace, uintptr_t addr, const char* fmt, ...);