Re: [PATCH 6/7] remove all remaining _syscallX macros

Arnd Bergmann
2006-08-28T14:06:23Z

On Monday 28 August 2006 12:00, David Woodhouse wrote:
> I'm trying to 'suddenly redefine' kernel headers as something that
> _isn't_ just a library of random crap for people to abuse in userspace
> as they see fit, then whine when something breaks even though it was
> never really guaranteed to work when abused in that way anyway.

Well, there are two points to consider here:

1. There is user space source code out that that used these macros
in the past, without feeling ashamed of it. It's fairly well-documented
and seems to be a common way for inexperienced people to use syscalls
before they get formal libc support.

2. There is a long history of bugs with these calls. The version with more
than 5 arguments is missing on some platforms, the assembly constraints
break if your gcc is too old or too new, it doesn't work at all on
non-gcc compiles, and libc and kernel are normally out of sync.
Expect any platform other than x86 to be broken ;-).

The patch below should address both these issues, as long as the libc
has a working implementation of syscall(2).

Of course, if Andi prefers, we can do this for all architectures except
x86 and let him keep the old code.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Index: linux-cg/include/asm-alpha/unistd.h
===================================================================
--- linux-cg.orig/include/asm-alpha/unistd.h 2006-08-28 11:08:52.000000000 +0200
+++ linux-cg/include/asm-alpha/unistd.h 2006-08-28 15:41:56.000000000 +0200
@@ -1,6 +1,8 @@
#ifndef _ALPHA_UNISTD_H
#define _ALPHA_UNISTD_H

+#include <asm-generic/unistd.h>
+
#define __NR_osf_syscall 0 /* not implemented */
#define __NR_exit 1
#define __NR_fork 2
Index: linux-cg/include/asm-arm/unistd.h
===================================================================
--- linux-cg.orig/include/asm-arm/unistd.h 2006-08-28 11:08:52.000000000 +0200
+++ linux-cg/include/asm-arm/unistd.h 2006-08-28 15:42:04.000000000 +0200
@@ -13,6 +13,8 @@
#ifndef __ASM_ARM_UNISTD_H
#define __ASM_ARM_UNISTD_H

+#include <asm-generic/unistd.h>
+
#define __NR_OABI_SYSCALL_BASE 0x900000

#if defined(__thumb__) || defined(__ARM_EABI__)
Index: linux-cg/include/asm-arm26/unistd.h
===================================================================
--- linux-cg.orig/include/asm-arm26/unistd.h 2006-08-28 11:08:52.000000000 +0200
+++ linux-cg/include/asm-arm26/unistd.h 2006-08-28 15:42:09.000000000 +0200
@@ -14,6 +14,8 @@
#ifndef __ASM_ARM_UNISTD_H
#define __ASM_ARM_UNISTD_H

+#include <asm-generic/unistd.h>
+
#define __NR_SYSCALL_BASE 0x900000

/*
Index: linux-cg/include/asm-cris/unistd.h
===================================================================
--- linux-cg.orig/include/asm-cris/unistd.h 2006-08-28 15:21:50.000000000 +0200
+++ linux-cg/include/asm-cris/unistd.h 2006-08-28 15:42:20.000000000 +0200
@@ -1,6 +1,7 @@
#ifndef _ASM_CRIS_UNISTD_H_
#define _ASM_CRIS_UNISTD_H_

+#include <asm-generic/unistd.h>
#include <asm/arch/unistd.h>

/*
Index: linux-cg/include/asm-frv/unistd.h
===================================================================
--- linux-cg.orig/include/asm-frv/unistd.h 2006-08-28 15:21:50.000000000 +0200
+++ linux-cg/include/asm-frv/unistd.h 2006-08-28 15:42:26.000000000 +0200
@@ -1,6 +1,8 @@
#ifndef _ASM_UNISTD_H_
#define _ASM_UNISTD_H_

+#include <asm-generic/unistd.h>
+
/*
* This file contains the system call numbers.
*/
Index: linux-cg/include/asm-generic/Kbuild
===================================================================
--- linux-cg.orig/include/asm-generic/Kbuild 2006-08-28 15:39:39.000000000 +0200
+++ linux-cg/include/asm-generic/Kbuild 2006-08-28 15:39:52.000000000 +0200
@@ -1,3 +1,3 @@
header-y += atomic.h errno-base.h errno.h fcntl.h ioctl.h ipc.h mman.h \
- signal.h statfs.h
+ signal.h statfs.h unistd.h
unifdef-y := resource.h siginfo.h
Index: linux-cg/include/asm-generic/unistd.h
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ linux-cg/include/asm-generic/unistd.h 2006-08-28 15:58:37.000000000 +0200
@@ -0,0 +1,76 @@
+#ifndef __ASM_GENERIC_UNISTD_H
+#define __ASM_GENERIC_UNISTD_H
+
+#ifndef __KERNEL__
+#include <sys/syscall.h>
+
+/*
+ * Applications should never rely on these macros, but instead
+ * use the syscall(2) function from libc.
+ *
+ * The purpose of the _syscallX() function is to generate a
+ * gcc warning about this.
+ */
+#ifdef __GNUC__
+static inline void __attribute__((deprecated)) _syscallX(void) { }
+#else
+static inline void _syscallX(void) { }
+#endif
+
+#define _syscall0(type, name) \
+type name(void) \
+{ \
+ _syscallX(); \
+ return (type)syscall(__NR_ ## name); \
+}
+
+#define _syscall1(type, name, type1, arg1) \
+type name(type1 arg1) \
+{ \
+ _syscallX(); \
+ return (type)syscall(__NR_ ## name, arg1); \
+}
+
+#define _syscall2(type, name, type1, arg1, type2, arg2) \
+type name(type1 arg1, type2 arg2) \
+{ \
+ _syscallX(); \
+ return (type)syscall(__NR_ ## name, arg1, arg2); \
+}
+
+#define _syscall3(type, name, type1, arg1, type2, arg2, type3, arg3) \
+type name(type1 arg1, type2 arg2, type3 arg3) \
+{ \
+ _syscallX(); \
+ return (type)syscall(__NR_ ## name, arg1, arg2, arg3); \
+}
+
+#define _syscall4(type, name, type1, arg1, type2, arg2, type3, arg3, \
+ type4, arg4) \
+type name(type1 arg1, type2 arg2, type3 arg3, type4 arg4) \
+{ \
+ _syscallX(); \
+ return (type)syscall(__NR_ ## name, arg1, arg2, arg3, arg4) \
+}
+
+#define _syscall5(type, name, type1, arg1, type2, arg2, type3, arg3, \
+ type4, arg4, type5, arg5) \
+type name(type1 arg1, type2 arg2, type3 arg3, type4 arg4, type5 arg5) \
+{ \
+ _syscallX(); \
+ return (type)syscall(__NR_ ## name, arg1, arg2, arg3, \
+ arg4, arg5); \
+}
+
+#define _syscall6(type, name, type1, arg1, type2, arg2, type3, arg3, \
+ type4, arg4, type5, arg5, type6, arg6) \
+type name(type1 arg1, type2 arg2, type3 arg3, type4 arg4, type5 arg5, \
+ type6 arg6) \
+{ \
+ _syscallX(); \
+ return (type)syscall(__NR_ ## name, arg1, arg2, arg3, \
+ arg4, arg5, arg6); \
+}
+
+#endif
+#endif
Index: linux-cg/include/asm-h8300/unistd.h
===================================================================
--- linux-cg.orig/include/asm-h8300/unistd.h 2006-08-28 15:21:50.000000000 +0200
+++ linux-cg/include/asm-h8300/unistd.h 2006-08-28 15:42:34.000000000 +0200
@@ -1,6 +1,8 @@
#ifndef _ASM_H8300_UNISTD_H_
#define _ASM_H8300_UNISTD_H_

+#include <asm-generic/unistd.h>
+
/*
* This file contains the system call numbers.
*/
Index: linux-cg/include/asm-i386/unistd.h
===================================================================
--- linux-cg.orig/include/asm-i386/unistd.h 2006-08-28 15:21:50.000000000 +0200
+++ linux-cg/include/asm-i386/unistd.h 2006-08-28 15:42:37.000000000 +0200
@@ -1,6 +1,8 @@
#ifndef _ASM_I386_UNISTD_H_
#define _ASM_I386_UNISTD_H_

+#include <asm-generic/unistd.h>
+
/*
* This file contains the system call numbers.
*/
Index: linux-cg/include/asm-ia64/unistd.h
===================================================================
--- linux-cg.orig/include/asm-ia64/unistd.h 2006-08-28 11:08:53.000000000 +0200
+++ linux-cg/include/asm-ia64/unistd.h 2006-08-28 15:42:46.000000000 +0200
@@ -9,6 +9,7 @@
*/

#include <asm/break.h>
+#include <asm-generic/unistd.h>

#define __BREAK_SYSCALL __IA64_BREAK_SYSCALL

Index: linux-cg/include/asm-m32r/unistd.h
===================================================================
--- linux-cg.orig/include/asm-m32r/unistd.h 2006-08-28 15:21:50.000000000 +0200
+++ linux-cg/include/asm-m32r/unistd.h 2006-08-28 15:42:55.000000000 +0200
@@ -4,6 +4,7 @@
/* $Id$ */

#include <asm/syscall.h> /* SYSCALL_* */
+#include <asm-generic/unistd.h>

/*
* This file contains the system call numbers.
Index: linux-cg/include/asm-m68k/unistd.h
===================================================================
--- linux-cg.orig/include/asm-m68k/unistd.h 2006-08-28 15:21:50.000000000 +0200
+++ linux-cg/include/asm-m68k/unistd.h 2006-08-28 15:42:59.000000000 +0200
@@ -1,6 +1,8 @@
#ifndef _ASM_M68K_UNISTD_H_
#define _ASM_M68K_UNISTD_H_

+#include <asm-generic/unistd.h>
+
/*
* This file contains the system call numbers.
*/
Index: linux-cg/include/asm-m68knommu/unistd.h
===================================================================
--- linux-cg.orig/include/asm-m68knommu/unistd.h 2006-08-28 15:21:50.000000000 +0200
+++ linux-cg/include/asm-m68knommu/unistd.h 2006-08-28 15:43:02.000000000 +0200
@@ -1,6 +1,8 @@
#ifndef _ASM_M68K_UNISTD_H_
#define _ASM_M68K_UNISTD_H_

+#include <asm-generic/unistd.h>
+
/*
* This file contains the system call numbers.
*/
Index: linux-cg/include/asm-mips/unistd.h
===================================================================
--- linux-cg.orig/include/asm-mips/unistd.h 2006-08-28 15:21:50.000000000 +0200
+++ linux-cg/include/asm-mips/unistd.h 2006-08-28 15:43:08.000000000 +0200
@@ -13,6 +13,7 @@
#define _ASM_UNISTD_H

#include <asm/sgidefs.h>
+#include <asm-generic/unistd.h>

#if _MIPS_SIM == _MIPS_SIM_ABI32

Index: linux-cg/include/asm-parisc/unistd.h
===================================================================
--- linux-cg.orig/include/asm-parisc/unistd.h 2006-08-28 11:08:52.000000000 +0200
+++ linux-cg/include/asm-parisc/unistd.h 2006-08-28 15:43:12.000000000 +0200
@@ -1,6 +1,8 @@
#ifndef _ASM_PARISC_UNISTD_H_
#define _ASM_PARISC_UNISTD_H_

+#include <asm-generic/unistd.h>
+
/*
* This file contains the system call numbers.
*/
Index: linux-cg/include/asm-powerpc/unistd.h
===================================================================
--- linux-cg.orig/include/asm-powerpc/unistd.h 2006-08-28 11:08:52.000000000 +0200
+++ linux-cg/include/asm-powerpc/unistd.h 2006-08-28 15:43:14.000000000 +0200
@@ -1,6 +1,8 @@
#ifndef _ASM_PPC_UNISTD_H_
#define _ASM_PPC_UNISTD_H_

+#include <asm-generic/unistd.h>
+
/*
* This file contains the system call numbers.
*
Index: linux-cg/include/asm-s390/unistd.h
===================================================================
--- linux-cg.orig/include/asm-s390/unistd.h 2006-08-28 15:21:50.000000000 +0200
+++ linux-cg/include/asm-s390/unistd.h 2006-08-28 15:43:19.000000000 +0200
@@ -9,6 +9,8 @@
#ifndef _ASM_S390_UNISTD_H_
#define _ASM_S390_UNISTD_H_

+#include <asm-generic/unistd.h>
+
/*
* This file contains the system call numbers.
*/
Index: linux-cg/include/asm-sh/unistd.h
===================================================================
--- linux-cg.orig/include/asm-sh/unistd.h 2006-08-28 15:21:50.000000000 +0200
+++ linux-cg/include/asm-sh/unistd.h 2006-08-28 15:43:23.000000000 +0200
@@ -1,6 +1,8 @@
#ifndef __ASM_SH_UNISTD_H
#define __ASM_SH_UNISTD_H

+#include <asm-generic/unistd.h>
+
/*
* Copyright (C) 1999 Niibe Yutaka
*/
Index: linux-cg/include/asm-sh64/unistd.h
===================================================================
--- linux-cg.orig/include/asm-sh64/unistd.h 2006-08-28 15:21:50.000000000 +0200
+++ linux-cg/include/asm-sh64/unistd.h 2006-08-28 15:43:27.000000000 +0200
@@ -1,6 +1,8 @@
#ifndef __ASM_SH64_UNISTD_H
#define __ASM_SH64_UNISTD_H

+#include <asm-generic/unistd.h>
+
/*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
Index: linux-cg/include/asm-sparc/unistd.h
===================================================================
--- linux-cg.orig/include/asm-sparc/unistd.h 2006-08-28 15:21:50.000000000 +0200
+++ linux-cg/include/asm-sparc/unistd.h 2006-08-28 15:43:31.000000000 +0200
@@ -2,6 +2,8 @@
#ifndef _SPARC_UNISTD_H
#define _SPARC_UNISTD_H

+#include <asm-generic/unistd.h>
+
/*
* System calls under the Sparc.
*
Index: linux-cg/include/asm-sparc64/unistd.h
===================================================================
--- linux-cg.orig/include/asm-sparc64/unistd.h 2006-08-28 15:21:50.000000000 +0200
+++ linux-cg/include/asm-sparc64/unistd.h 2006-08-28 15:43:34.000000000 +0200
@@ -2,6 +2,8 @@
#ifndef _SPARC64_UNISTD_H
#define _SPARC64_UNISTD_H

+#include <asm-generic/unistd.h>
+
/*
* System calls under the Sparc.
*
Index: linux-cg/include/asm-v850/unistd.h
===================================================================
--- linux-cg.orig/include/asm-v850/unistd.h 2006-08-28 15:21:50.000000000 +0200
+++ linux-cg/include/asm-v850/unistd.h 2006-08-28 15:44:07.000000000 +0200
@@ -14,6 +14,8 @@
#ifndef __V850_UNISTD_H__
#define __V850_UNISTD_H__

+#include <asm-generic/unistd.h>
+
#define __NR_restart_syscall 0
#define __NR_exit 1
#define __NR_fork 2
Index: linux-cg/include/asm-x86_64/unistd.h
===================================================================
--- linux-cg.orig/include/asm-x86_64/unistd.h 2006-08-28 11:08:52.000000000 +0200
+++ linux-cg/include/asm-x86_64/unistd.h 2006-08-28 15:44:11.000000000 +0200
@@ -1,6 +1,8 @@
#ifndef _ASM_X86_64_UNISTD_H_
#define _ASM_X86_64_UNISTD_H_

+#include <asm-generic/unistd.h>
+
#ifndef __SYSCALL
#define __SYSCALL(a,b)
#endif
Index: linux-cg/include/asm-xtensa/unistd.h
===================================================================
--- linux-cg.orig/include/asm-xtensa/unistd.h 2006-08-28 15:21:51.000000000 +0200
+++ linux-cg/include/asm-xtensa/unistd.h 2006-08-28 15:44:15.000000000 +0200
@@ -11,6 +11,8 @@
#ifndef _XTENSA_UNISTD_H
#define _XTENSA_UNISTD_H

+#include <asm-generic/unistd.h>
+
#define __NR_spill 0
#define __NR_exit 1
#define __NR_read 3