From 95d82acc57bb7d8bae431f7a6ce0707aac3ef33f Mon Sep 17 00:00:00 2001
From: Rosen Penev <rosenp@gmail.com>
Date: Thu, 5 Sep 2019 19:41:13 -0700
Subject: [PATCH] Use eventfd() function with uClibc

The Boost eventfd code either directly makes the eventfd system call
using __NR_eventfd (when __GLIBC_MINOR is less than 8), or otherwise
uses the eventfd() function provided by the C library.

However, since uClibc pretends to be glibc 2.2, the Boost eventfd code
directly uses the system call. While it works fine on most
architectures, it doesn't on ARC since __NR_eventfd is not defined on
this architecture. However, eventfd() is properly implemented.

So, this patch adjusts the logic used by Boost to consider uClibc as a
C library providing the eventfd() function.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Rosen Penev <rosenp@gmail.com>
---
 a/boost/asio/detail/impl/eventfd_select_interrupter.ipp  | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/boost/asio/detail/impl/eventfd_select_interrupter.ipp b/boost/asio/detail/impl/eventfd_select_interrupter.ipp
index 38d4b2a61..e16cc8b00 100644
--- a/boost/asio/detail/impl/eventfd_select_interrupter.ipp
+++ b/boost/asio/detail/impl/eventfd_select_interrupter.ipp
@@ -23,11 +23,11 @@
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <fcntl.h>
-#if __GLIBC__ == 2 && __GLIBC_MINOR__ < 8
+#if __GLIBC__ == 2 && __GLIBC_MINOR__ < 2
 # include <asm/unistd.h>
-#else // __GLIBC__ == 2 && __GLIBC_MINOR__ < 8
+#else // __GLIBC__ == 2 && __GLIBC_MINOR__ < 2
 # include <sys/eventfd.h>
-#endif // __GLIBC__ == 2 && __GLIBC_MINOR__ < 8
+#endif // __GLIBC__ == 2 && __GLIBC_MINOR__ < 2
 #include <boost/asio/detail/cstdint.hpp>
 #include <boost/asio/detail/eventfd_select_interrupter.hpp>
 #include <boost/asio/detail/throw_error.hpp>
@@ -46,14 +46,14 @@ eventfd_select_interrupter::eventfd_select_interrupter()
 
 void eventfd_select_interrupter::open_descriptors()
 {
-#if __GLIBC__ == 2 && __GLIBC_MINOR__ < 8
+#if __GLIBC__ == 2 && __GLIBC_MINOR__ < 2
   write_descriptor_ = read_descriptor_ = syscall(__NR_eventfd, 0);
   if (read_descriptor_ != -1)
   {
     ::fcntl(read_descriptor_, F_SETFL, O_NONBLOCK);
     ::fcntl(read_descriptor_, F_SETFD, FD_CLOEXEC);
   }
-#else // __GLIBC__ == 2 && __GLIBC_MINOR__ < 8
+#else // __GLIBC__ == 2 && __GLIBC_MINOR__ < 2
 # if defined(EFD_CLOEXEC) && defined(EFD_NONBLOCK)
   write_descriptor_ = read_descriptor_ =
     ::eventfd(0, EFD_CLOEXEC | EFD_NONBLOCK);
@@ -70,7 +70,7 @@ void eventfd_select_interrupter::open_descriptors()
       ::fcntl(read_descriptor_, F_SETFD, FD_CLOEXEC);
     }
   }
-#endif // __GLIBC__ == 2 && __GLIBC_MINOR__ < 8
+#endif // __GLIBC__ == 2 && __GLIBC_MINOR__ < 2
 
   if (read_descriptor_ == -1)
   {