POSIX threads and thread-local storage is needed for concurrent execution

aclocal.m4

@@ -1,5 +1,6 @@
 dnl ** Additional Autoconf tests for BIRD configure script
 dnl ** (c) 1999 Martin Mares <mj@ucw.cz>
+dnl ** (c) 2021 Maria Matejka <mq@jmq.cz>
 
 AC_DEFUN([BIRD_CHECK_THREAD_LOCAL],
 [
@@ -9,14 +10,23 @@ AC_DEFUN([BIRD_CHECK_THREAD_LOCAL],
     AC_COMPILE_IFELSE([
       AC_LANG_PROGRAM(
         [
-	  _Thread_local static int x = 42;
+	  static _Thread_local int x = 42;
 	],
 	[]
       )
     ],
     [bird_cv_thread_local=yes],
+    [AC_COMPILE_IFELSE([
+      AC_LANG_PROGRAM(
+       [
+         static __thread int x = 42;
+       ],
+       []
+      )
+    ],
+    [bird_cv_thread_local=__thread],
     [bird_cv_thread_local=no]
-    )
+    )])
   )
 ])
 

configure.ac

@@ -36,12 +36,6 @@ AC_ARG_ENABLE([memcheck],
   [enable_memcheck=yes]
 )
 
-AC_ARG_ENABLE([pthreads],
-  [AS_HELP_STRING([--enable-pthreads], [enable POSIX threads support @<:@try@:>@])],
-  [],
-  [enable_pthreads=try]
-)
-
 AC_ARG_ENABLE([libssh],
   [AS_HELP_STRING([--enable-libssh], [enable LibSSH support in RPKI @<:@try@:>@])],
   [],
@@ -125,25 +119,19 @@ if test -z "$GCC" ; then
 fi
 
 BIRD_CHECK_THREAD_LOCAL
-if test "$bird_cv_thread_local" = yes ; then
+if test "$bird_cv_thread_local" = no ; then
-  AC_DEFINE([HAVE_THREAD_LOCAL], [1], [Define to 1 if _Thread_local is available])
+  AC_MSG_ERROR([This program requires thread local storage.])
+elif test "$bird_cv_thread_local" != yes ; then
+  AC_DEFINE_UNQUOTED([_Thread_local], [$bird_cv_thread_local], [Legacy _Thread_local])
 fi
 
-if test "$enable_pthreads" != no ; then
+BIRD_CHECK_PTHREADS
-  BIRD_CHECK_PTHREADS
 
-  if test "$bird_cv_lib_pthreads" = yes ; then
+if test "$bird_cv_lib_pthreads" = yes ; then
-    AC_DEFINE([USE_PTHREADS], [1], [Define to 1 if pthreads are enabled])
+  CFLAGS="$CFLAGS -pthread"
-    CFLAGS="$CFLAGS -pthread"
+  LDFLAGS="$LDFLAGS -pthread"
-    LDFLAGS="$LDFLAGS -pthread"
+else
-    proto_bfd=bfd
+  AC_MSG_ERROR([POSIX threads not available.])
-  elif test "$enable_pthreads" = yes ; then
-    AC_MSG_ERROR([POSIX threads not available.])
-  fi
-
-  if test "$enable_pthreads" = try ; then
-    enable_pthreads="$bird_cv_lib_pthreads"
-  fi
 fi
 
 # This is assumed to be necessary for proper BIRD build
@@ -304,8 +292,7 @@ if test "$enable_mpls_kernel" != no ; then
   fi
 fi
 
-all_protocols="$proto_bfd babel bgp mrt ospf perf pipe radv rip rpki static"
+all_protocols="bfd babel bgp mrt ospf perf pipe radv rip rpki static"
-
 all_protocols=`echo $all_protocols | sed 's/ /,/g'`
 
 if test "$with_protocols" = all ; then
@@ -351,9 +338,15 @@ case $sysdesc in
 esac
 
 AC_CHECK_HEADERS_ONCE([alloca.h syslog.h])
-AC_CHECK_HEADER([sys/mman.h], [AC_DEFINE([HAVE_MMAP], [1], [Define to 1 if mmap() is available.])])
+AC_CHECK_HEADER([sys/mman.h], [AC_DEFINE([HAVE_MMAP], [1], [Define to 1 if mmap() is available.])], have_mman=no)
+AC_CHECK_FUNC([aligned_alloc], [AC_DEFINE([HAVE_ALIGNED_ALLOC], [1], [Define to 1 if aligned_alloc() is available.])], have_aligned_alloc=no)
 AC_CHECK_MEMBERS([struct sockaddr.sa_len], [], [], [#include <sys/socket.h>])
 
+if test "$have_aligned_alloc" = "no" && test "$have_mman" = "no" ; then
+  AC_MSG_ERROR([No means of aligned alloc found. Need mmap() or aligned_alloc().])
+fi
+
+
 AC_C_BIGENDIAN(
   [AC_DEFINE([CPU_BIG_ENDIAN], [1], [Define to 1 if cpu is big endian])],
   [AC_DEFINE([CPU_LITTLE_ENDIAN], [1], [Define to 1 if cpu is little endian])],
@@ -402,7 +395,7 @@ if test "$enable_debug" = yes ; then
     fi
   fi
 
-  if test "enable_debug_expensive" = yes ; then
+  if test "$enable_debug_expensive" = yes ; then
     AC_DEFINE([ENABLE_EXPENSIVE_CHECKS], [1], [Define to 1 if you want to run expensive consistency checks.])
   fi
 fi
@@ -467,7 +460,6 @@ AC_MSG_RESULT([        Object directory:	$objdir])
 AC_MSG_RESULT([        Iproute2 directory:	$iproutedir])
 AC_MSG_RESULT([        System configuration:	$sysdesc])
 AC_MSG_RESULT([        Debugging:		$enable_debug])
-AC_MSG_RESULT([        POSIX threads:		$enable_pthreads])
 AC_MSG_RESULT([        Routing protocols:	$protocols])
 AC_MSG_RESULT([        LibSSH support in RPKI:	$enable_libssh])
 AC_MSG_RESULT([        Kernel MPLS support:	$enable_mpls_kernel])

lib/birdlib.h

@@ -77,10 +77,6 @@ static inline int u64_cmp(u64 i1, u64 i2)
 #define STATIC_ASSERT(EXP) _Static_assert(EXP, #EXP)
 #define STATIC_ASSERT_MSG(EXP,MSG) _Static_assert(EXP, MSG)
 
-#ifndef HAVE_THREAD_LOCAL
-#define _Thread_local
-#endif
-
 /* Microsecond time */
 
 typedef s64 btime;

lib/timer.c

@@ -40,8 +40,6 @@
 struct timeloop main_timeloop;
 
 
-#ifdef USE_PTHREADS
-
 #include <pthread.h>
 
 /* Data accessed and modified from proto/bfd/io.c */
@@ -62,14 +60,6 @@ timeloop_init_current(void)
 
 void wakeup_kick_current(void);
 
-#else
-
-/* Just use main timelooop */
-static inline struct timeloop * timeloop_current(void) { return &main_timeloop; }
-static inline void timeloop_init_current(void) { }
-
-#endif
-
 btime
 current_time(void)
 {

sysdep/unix/log.c

@@ -36,8 +36,6 @@ static list *current_log_list;
 static char *current_syslog_name; /* NULL -> syslog closed */
 
 
-#ifdef USE_PTHREADS
-
 #include <pthread.h>
 
 static pthread_mutex_t log_mutex;
@@ -48,15 +46,6 @@ static pthread_t main_thread;
 void main_thread_init(void) { main_thread = pthread_self(); }
 static int main_thread_self(void) { return pthread_equal(pthread_self(), main_thread); }
 
-#else
-
-static inline void log_lock(void) {  }
-static inline void log_unlock(void) {  }
-void main_thread_init(void) { }
-static int main_thread_self(void) { return 1; }
-
-#endif
-
 
 #ifdef HAVE_SYSLOG_H
 #include <sys/syslog.h>