This is the mail archive of the mailing list for the glibc project.

Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

[COMMITTED PATCH 3/3] Clean up NPTL system to be compat-only.

I don't know if there was a historical reason for libpthread to have a
system wrapper, but there is certainly none in the current code.  This
change makes it compat-only.

Tested x86_64-linux-gnu.


	* nptl/pt-system.c: Rewritten.  Put everything under
	[SHLIB_COMPAT (libpthread, GLIBC_2_0, GLIBC_2_22)].
	Use IFUNC to redirect when possible.

--- a/nptl/pt-system.c
+++ b/nptl/pt-system.c
@@ -1,4 +1,5 @@
-/* Copyright (C) 2002-2015 Free Software Foundation, Inc.
+/* ABI compatibility for 'system' symbol in libpthread ABI.
+   Copyright (C) 2002-2015 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Ulrich Drepper <>, 2002.
@@ -16,17 +17,48 @@
    License along with the GNU C Library; if not, see
    <>.  */
-#include <errno.h>
 #include <stdlib.h>
-#include <sysdep.h>
-#include "pthreadP.h"
+#include <shlib-compat.h>
+/* libpthread once had its own 'system', though there was no apparent
+   reason for it.  There is no use in having a separate symbol in
+   libpthread, but the historical ABI requires it.  For static linking,
+   there is no need to provide anything here--the libc version will be
+   linked in.  For shared library ABI compatibility, there must be a
+   'system' symbol in; so we define it using IFUNC to
+   redirect to the libc function.  */
-system (const char *line)
+#if SHLIB_COMPAT (libpthread, GLIBC_2_0, GLIBC_2_22)
+static __typeof (system) *
+__attribute__ ((used))
+system_resolve (void)
+  return &__libc_system;
+asm (".globl system_ifunc\n"
+     ".type system_ifunc, %gnu_indirect_function");
+asm (".set system_ifunc, system_resolve");
+#  else
+asm ("system_ifunc = system_resolve");
+#  endif
+# else  /* !HAVE_IFUNC */
+static int __attribute__ ((used))
+system_compat (const char *line)
   return __libc_system (line);
+strong_alias (system_compat, system_ifunc)
+# endif  /* HAVE_IFUNC */
+compat_symbol (libpthread, system_ifunc, system, GLIBC_2_0);
-/* __libc_system in handles cancellation.  */

Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]