From 40e9724de723249aec9cccedf489c7c15b6d6879 Mon Sep 17 00:00:00 2001
From: Seth Hall <seth@icir.org>
Date: Sat, 7 May 2016 01:22:38 -0400
Subject: [PATCH] Switching all use of gmtime and localtime to use reentrant
 variants.

This was causing occasional problems with the time on processes
running lots of threads.  The use of gmtime in the json
formatter is the likely culprit due to the fact that the
json formatter runs in threads.  More evidence for this is that
the problem only appears to exhibit when logs are being written
as JSON.
---
 src/bro.bif                      | 18 +++++++++++++-----
 src/threading/formatters/JSON.cc | 21 ++++++++++++++-------
 src/util.cc                      |  9 ++++++++-
 3 files changed, 35 insertions(+), 13 deletions(-)

diff --git a/src/bro.bif b/src/bro.bif
index f21f927f92..e2baf62550 100644
--- a/src/bro.bif
+++ b/src/bro.bif
@@ -145,12 +145,17 @@ static void do_fmt(const char*& fmt, Val* v, ODesc* d)
 			}
 
 		time_t time = time_t(v->InternalDouble());
+		struct tm t;
+
 		int is_time_fmt = *fmt == 'T';
 
+		if ( ! localtime_r(&time, &t) )
+			s.AddSP("<problem getting time>");
+
 		if ( ! strftime(out_buf, sizeof(out_buf),
 				is_time_fmt ?
 					"%Y-%m-%d-%H:%M" : "%Y-%m-%d-%H:%M:%S",
-				localtime(&time)) )
+				&t) )
 			s.AddSP("<bad time>");
 
 		else
@@ -3140,9 +3145,11 @@ function strftime%(fmt: string, d: time%) : string
 	%{
 	static char buffer[128];
 
-	time_t t = time_t(d);
+	time_t timeval = time_t(d);
+	struct tm t;
 
-	if ( strftime(buffer, 128, fmt->CheckString(), localtime(&t)) == 0 )
+	if ( ! localtime_r(&timeval, &t) ||
+	     ! strftime(buffer, 128, fmt->CheckString(), &t) )
 		return new StringVal("<strftime error>");
 
 	return new StringVal(buffer);
@@ -3160,9 +3167,10 @@ function strftime%(fmt: string, d: time%) : string
 function strptime%(fmt: string, d: string%) : time
 	%{
 	const time_t timeval = time_t();
-	struct tm t = *localtime(&timeval);
+	struct tm t;
 
-	if ( strptime(d->CheckString(), fmt->CheckString(), &t) == NULL )
+	if ( ! localtime_r(&timeval, &t) || 
+	     ! strptime(d->CheckString(), fmt->CheckString(), &t) )
 		{
 		reporter->Warning("strptime conversion failed: fmt:%s d:%s", fmt->CheckString(), d->CheckString());
 		return new Val(0.0, TYPE_TIME);
diff --git a/src/threading/formatters/JSON.cc b/src/threading/formatters/JSON.cc
index 3558baee5c..45c7be3e93 100644
--- a/src/threading/formatters/JSON.cc
+++ b/src/threading/formatters/JSON.cc
@@ -116,21 +116,28 @@ bool JSON::Describe(ODesc* desc, Value* val, const string& name) const
 				{
 				char buffer[40];
 				char buffer2[40];
-				time_t t = time_t(val->val.double_val);
+				time_t the_time = time_t(val->val.double_val);
+				struct tm t;
 
-				if ( strftime(buffer, sizeof(buffer), "%Y-%m-%dT%H:%M:%S", gmtime(&t)) > 0 )
+				desc->AddRaw("\"", 1);
+
+				if ( ! gmtime_r(&the_time, &t) ||
+				     ! strftime(buffer, sizeof(buffer), "%Y-%m-%dT%H:%M:%S", &t) )
+					{
+					GetThread()->Error(GetThread()->Fmt("json formatter: failure getting time: (%" PRIu64 ")", val->val.double_val));
+					// This was a failure, doesn't really matter what gets put here
+					// but it should probably stand out...
+					desc->Add("2000-01-01T00:00:00.000000");
+					}
+				else
 					{
 					double integ;
 					double frac = modf(val->val.double_val, &integ);
 					snprintf(buffer2, sizeof(buffer2), "%s.%06.0fZ", buffer, frac * 1000000);
-					desc->AddRaw("\"", 1);
 					desc->Add(buffer2);
-					desc->AddRaw("\"", 1);
 					}
 
-				else
-					GetThread()->Error(GetThread()->Fmt("strftime error for JSON: %" PRIu64));
-
+				desc->AddRaw("\"", 1);
 				}
 
 			else if ( timestamps == TS_EPOCH )
diff --git a/src/util.cc b/src/util.cc
index 0ea89beb90..1f10d7446d 100644
--- a/src/util.cc
+++ b/src/util.cc
@@ -571,7 +571,14 @@ const char* fmt_access_time(double t)
 	{
 	static char buf[256];
 	time_t time = (time_t) t;
-	strftime(buf, sizeof(buf), "%d/%m-%H:%M", localtime(&time));
+	struct tm ts;
+
+	if ( ! localtime_r(&time, &ts) )
+		{
+		reporter->InternalError("unable to get time");
+		}
+
+	strftime(buf, sizeof(buf), "%d/%m-%H:%M", &ts);
 	return buf;
 	}