From 9219d330e9b25573d0ce897407e259f684a7c5d0 Mon Sep 17 00:00:00 2001
From: Ali Mashtizadeh <mashti@cs.stanford.edu>
Date: Wed, 16 Dec 2015 17:38:31 -0800
Subject: [PATCH] Expose the per-thread errno variable

---
 include/errno.h          |  5 +++++
 lib/libc/posix/pthread.c | 11 ++++++++++-
 2 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/include/errno.h b/include/errno.h
index 691236a..e603073 100644
--- a/include/errno.h
+++ b/include/errno.h
@@ -2,6 +2,11 @@
 #ifndef __ERRNO_H__
 #define __ERRNO_H__
 
+#ifndef _KERNEL
+int *__error();
+#define errno		(* __error())
+#endif
+
 #define EIO		0x1BAD0001
 #define EBADF		0x1BAD0002
 #define EINVAL		0x1BAD0003
diff --git a/lib/libc/posix/pthread.c b/lib/libc/posix/pthread.c
index 3aa0c57..9b73058 100644
--- a/lib/libc/posix/pthread.c
+++ b/lib/libc/posix/pthread.c
@@ -20,7 +20,7 @@ struct pthread_attr {
 
 struct pthread {
     uint64_t	tid;
-    int		errno;
+    int		error;			    // errno
     TAILQ_ENTRY(pthread)    threadTable;
 
     // Initialization
@@ -41,6 +41,14 @@ typedef TAILQ_HEAD(pthreadList, pthread) pthreadList;
 static CoreMutex __threadTableLock;
 static pthreadList __threads[THREAD_HASH_SLOTS];
 
+int *
+__error(void)
+{
+    struct pthread *pth = pthread_self();
+
+    return &(pth->error);
+}
+
 void
 __pthread_init(void)
 {
@@ -56,6 +64,7 @@ __pthread_init(void)
     }
 
     thr->tid = OSGetTID();
+    thr->error = 0;
     thr->entry = NULL;
     thr->arg = 0;