From e0bebc7c223abf239b5ccda1c2de42a2b0410455 Mon Sep 17 00:00:00 2001
From: Quentin Young <qlyoung@cumulusnetworks.com>
Date: Thu, 15 Jun 2017 16:05:19 +0000
Subject: [PATCH] lib: mt-safe tracebacks

can't be using them statics anymore sonny

Signed-off-by: Quentin Young <qlyoung@cumulusnetworks.com>
---
 lib/log.c    | 19 ++++++++++++-------
 lib/thread.c | 29 +++++++++++++++++------------
 lib/thread.h |  2 +-
 3 files changed, 30 insertions(+), 20 deletions(-)

diff --git a/lib/log.c b/lib/log.c
index a8b221fd64..1c61d72168 100644
--- a/lib/log.c
+++ b/lib/log.c
@@ -509,16 +509,18 @@ zlog_signal(int signo, const char *action
 			);
 
   s = buf;
-  if (!thread_current)
+  struct thread *tc;
+  tc = pthread_getspecific (thread_current);
+  if (!tc)
     s = str_append (LOC, "no thread information available\n");
   else
     {
       s = str_append (LOC, "in thread ");
-      s = str_append (LOC, thread_current->funcname);
+      s = str_append (LOC, tc->funcname);
       s = str_append (LOC, " scheduled from ");
-      s = str_append (LOC, thread_current->schedfrom);
+      s = str_append (LOC, tc->schedfrom);
       s = str_append (LOC, ":");
-      s = num_append (LOC, thread_current->schedfrom_line);
+      s = num_append (LOC, tc->schedfrom_line);
       s = str_append (LOC, "\n");
     }
 
@@ -700,10 +702,13 @@ ZLOG_FUNC(zlog_debug, LOG_DEBUG)
 
 void zlog_thread_info (int log_level)
 {
-  if (thread_current)
+  struct thread *tc;
+  tc = pthread_getspecific (thread_current);
+
+  if (tc)
     zlog(log_level, "Current thread function %s, scheduled from "
-	 "file %s, line %u", thread_current->funcname,
-	 thread_current->schedfrom, thread_current->schedfrom_line);
+	 "file %s, line %u", tc->funcname,
+	 tc->schedfrom, tc->schedfrom_line);
   else
     zlog(log_level, "Current thread not known/applicable");
 }
diff --git a/lib/thread.c b/lib/thread.c
index 335e7fc044..feeffd31e8 100644
--- a/lib/thread.c
+++ b/lib/thread.c
@@ -47,8 +47,10 @@ DEFINE_MTYPE_STATIC(LIB, THREAD_STATS,  "Thread stats")
       write (m->io_pipe[1], &wakebyte, 1); \
   } while (0);
 
+pthread_once_t init_once = PTHREAD_ONCE_INIT;
 static pthread_mutex_t cpu_record_mtx = PTHREAD_MUTEX_INITIALIZER;
 static struct hash *cpu_record = NULL;
+pthread_key_t thread_current;
 
 static unsigned long
 timeval_elapsed (struct timeval a, struct timeval b)
@@ -334,6 +336,17 @@ cancelreq_del (void *cr)
   XFREE (MTYPE_TMP, cr);
 }
 
+/* initializer, only ever called once */
+static void initializer ()
+{
+  if (cpu_record == NULL)
+    cpu_record = hash_create ((unsigned int (*) (void *))cpu_record_hash_key,
+                              (int (*) (const void *, const void *))
+                              cpu_record_hash_cmp);
+
+  pthread_key_create (&thread_current, NULL);
+}
+
 /* Allocate new thread master.  */
 struct thread_master *
 thread_master_create (void)
@@ -343,14 +356,7 @@ thread_master_create (void)
 
   getrlimit(RLIMIT_NOFILE, &limit);
 
-  pthread_mutex_lock (&cpu_record_mtx);
-  {
-    if (cpu_record == NULL)
-      cpu_record = hash_create ((unsigned int (*) (void *))cpu_record_hash_key,
-                                (int (*) (const void *, const void *))
-                                cpu_record_hash_cmp);
-  }
-  pthread_mutex_unlock (&cpu_record_mtx);
+  pthread_once (&init_once, &initializer);
 
   rv = XCALLOC (MTYPE_THREAD_MASTER, sizeof (struct thread_master));
   if (rv == NULL)
@@ -1096,6 +1102,7 @@ thread_cancel (struct thread *thread)
     listnode_add (thread->master->cancel_req, cr);
     do_thread_cancel (thread->master);
   }
+done:
   pthread_mutex_unlock (&thread->master->mtx);
 }
 
@@ -1449,8 +1456,6 @@ thread_getrusage (RUSAGE_T *r)
   getrusage(RUSAGE_SELF, &(r->cpu));
 }
 
-struct thread *thread_current = NULL;
-
 /* We check thread consumed time. If the system has getrusage, we'll
    use that to get in-depth stats on the performance of the thread in addition
    to wall clock time stats from gettimeofday. */
@@ -1463,9 +1468,9 @@ thread_call (struct thread *thread)
   GETRUSAGE (&before);
   thread->real = before.real;
 
-  thread_current = thread;
+  pthread_setspecific (thread_current, thread);
   (*thread->func) (thread);
-  thread_current = NULL;
+  pthread_setspecific (thread_current, NULL);
 
   GETRUSAGE (&after);
 
diff --git a/lib/thread.h b/lib/thread.h
index e48068b174..1760a930f9 100644
--- a/lib/thread.h
+++ b/lib/thread.h
@@ -220,6 +220,6 @@ extern unsigned long thread_consumed_time(RUSAGE_T *after, RUSAGE_T *before,
 					  unsigned long *cpu_time_elapsed);
 
 /* only for use in logging functions! */
-extern struct thread *thread_current;
+extern pthread_key_t thread_current;
 
 #endif /* _ZEBRA_THREAD_H */
-- 
2.39.5