Fix linux personality syscall wrapper

The personality system call, starting with linux kernel commit
v2.6.29-6609-g11d06b2a1e5658f448a308aa3beb97bacd64a940, always
successfully changes the personality if requested.  The syscall
wrapper, however, still can return an error in the following cases:
- the value returned by the system call looks like an error
due to architecture limitations of 32-bit kernels;
- a personality greater than 0xffffffff is passed to the system call,
and the 64-bit kernel does not have commit
v2.6.35-rc1-372-g485d527686850d68a0e9006dd9904f19f122485e
that would truncate this value to unsigned int;
- on sparc64, the value returned by the system call looks like an error
due to sparc64 kernel sign extension bug.

The solution is three-fold:
- move generic syscalls.list personality entry to generic 64-bit
syscalls.list file;
- for each 32-bit architecture that use negated errno semantics,
add a NOERRNO personality entry to their syscalls.list file;
- for sparc64 and 32-bit architectures that use dedicated registers
to flag syscall errors, add a wrapper around personality syscall;
if the system call return value is flagged as an error, this wrapper
returns the negated "would be errno" value, otherwise it returns
the system call return value; on sparc64, it also truncates the
personality argument to unsigned int before passing it to the kernel.

[BZ #19408]
* sysdeps/unix/sysv/linux/personality.c: New file.
* sysdeps/unix/sysv/linux/sparc/sparc64/personality.c: Likewise.
* sysdeps/unix/sysv/linux/tst-personality.c: Likewise.
* sysdeps/unix/sysv/linux/Makefile [$(subdir) == misc]
(sysdep_routines): Add personality.
(tests): Add tst-personality.
* sysdeps/unix/sysv/linux/syscalls.list (personality): Move ...
* sysdeps/unix/sysv/linux/wordsize-64/syscalls.list: ... here.
* sysdeps/unix/sysv/linux/arm/syscalls.list (personality): New entry.
* sysdeps/unix/sysv/linux/hppa/syscalls.list (personality): Likewise.
* sysdeps/unix/sysv/linux/i386/syscalls.list (personality): Likewise.
* sysdeps/unix/sysv/linux/m68k/syscalls.list (personality): Likewise.
* sysdeps/unix/sysv/linux/microblaze/syscalls.list (personality):
Likewise.
* sysdeps/unix/sysv/linux/mips/mips64/n32/syscalls.list (personality):
Likewise.
* sysdeps/unix/sysv/linux/s390/s390-32/syscalls.list (personality):
Likewise.
* sysdeps/unix/sysv/linux/sh/syscalls.list (personality): Likewise.
* sysdeps/unix/sysv/linux/x86_64/x32/syscalls.list (personality):
Likewise.

1 files changed, 49 insertions, 0 deletions

diff --git a/sysdeps/unix/sysv/linux/personality.c b/sysdeps/unix/sysv/linux/personality.c
new file mode 100644
index 0000000..6724f1b
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/personality.c
@@ -0,0 +1,49 @@
+/* Copyright (C) 2015 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <sys/personality.h>
+#include <sysdep.h>
+
+extern __typeof (personality) __personality;
+
+int
+__personality (unsigned long persona)
+{
+#ifdef PERSONALITY_TRUNCATE_ARGUMENT
+  /* Starting with kernel commit v2.6.21-3117-g97dc32c, the type of
+     task_struct->pesonality is "unsigned int".
+     Starting with kernel commit v2.6.35-rc1-372-g485d527, the personality
+     syscall accepts "unsigned int" instead of "long unsigned int".
+     Inbetween, a personality argument that does not fit into "unsigned int"
+     would result to system call returning -EINVAL.
+     We explicitly truncate the personality argument to "unsigned int"
+     to eliminate the uncertainty.  */
+  persona = (unsigned int) persona;
+#endif
+
+  INTERNAL_SYSCALL_DECL (err);
+  long ret = INTERNAL_SYSCALL (personality, err, 1, persona);
+
+  /* Starting with kernel commit v2.6.29-6609-g11d06b2, the personality syscall
+     never fails.  However, 32-bit kernels might flag valid values as errors, so
+     we need to reverse the error setting.  We can't use the raw result as some
+     arches split the return/error values.  */
+  if (__glibc_unlikely (INTERNAL_SYSCALL_ERROR_P (ret, err)))
+    ret = -INTERNAL_SYSCALL_ERRNO (ret, err);
+  return ret;
+}
+weak_alias (__personality, personality)