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[PATCH] Prevent open_not_cancel etc. from being inlined
- From: Mark Seaborn <mseaborn at onetel dot com>
- To: libc-alpha at sources dot redhat dot com
- Date: Sun, 16 Oct 2005 18:53:08 +0100 (BST)
- Subject: [PATCH] Prevent open_not_cancel etc. from being inlined
The file sysdeps/unix/sysv/linux/not-cancel.h causes the
non-cancellable versions of some system calls to be inlined. This
patch prevents these definitions from being inlined. It moves them
into separate *.c files.
This is used for building Plash's modified version of glibc.
Background: Plash is a secure, restricted execution environment that
provides functionality similar to chroot(), but more flexible and
lightweight. It works partly by dynamically linking Linux executables
with a modified glibc. This is not used for taking authority away
from a process, only for giving it back. This approach is more
complete than using LD_PRELOADed libraries. There's more information
on what Plash does at <http://plash.beasts.org>.
Plash builds its custom glibc by re-linking the object files produced
by the glibc build process. It omits the object files for various
system calls and replaces them with its own code. For this to work
completely, those system calls cannot be inlined.
It would be useful if the patch could be included in mainline glibc so
that Plash can be built from binary packages of glibc's object files
(such as Debian's libc6-pic) and so that the patch doesn't have to be
maintained separately.
Performance shouldn't be an issue with this inlining: These calls are
not inlined in the NPTL version.
It seems that the inlining was done for convenience rather than
performance. Linuxthreads needs to use close_not_cancel. Usually
Linuxthreads builds its own versions of syscall object files
(eg. ptw-close.os), but it can only do this for object files built
from the syscall assembly code, not from C files. NPTL takes a
different approach and provides a *_nocancel symbol, built by the
syscall assembly code.
I put close_not_cancel in a C file in the patch, so I had to make
Linuxthreads a special case: not-cancel.h inlines the calls when used
from Linuxthreads. It might be cleaner to use NPTL's approach though.
Please let me know if the patch's functionality is acceptable but
you'd prefer if it were done this way instead.
Mark
diff -urN glibc-2.3.5.orig/nptl/sysdeps/unix/sysv/linux/i386/not-cancel.h glibc-2.3.5.new/nptl/sysdeps/unix/sysv/linux/i386/not-cancel.h
--- glibc-2.3.5.orig/nptl/sysdeps/unix/sysv/linux/i386/not-cancel.h Thu Sep 4 10:03:28 2003
+++ glibc-2.3.5.new/nptl/sysdeps/unix/sysv/linux/i386/not-cancel.h Sat Sep 24 21:19:15 2005
@@ -44,10 +44,19 @@
/* Uncancelable close. */
#define close_not_cancel(fd) \
__close_nocancel (fd)
+
+#if defined NOT_IN_libc && !defined IS_IN_rtld
+
#define close_not_cancel_no_status(fd) \
(void) ({ INTERNAL_SYSCALL_DECL (err); \
INTERNAL_SYSCALL (close, err, 1, (fd)); })
+#else
+
+void close_not_cancel_no_status(int fd);
+
+#endif
+
/* Uncancelable read. */
#define read_not_cancel(fd, buf, n) \
__read_nocancel (fd, buf, n)
@@ -57,9 +66,7 @@
__write_nocancel (fd, buf, n)
/* Uncancelable writev. */
-#define writev_not_cancel_no_status(fd, iov, n) \
- (void) ({ INTERNAL_SYSCALL_DECL (err); \
- INTERNAL_SYSCALL (writev, err, 3, (fd), (iov), (n)); })
+void writev_not_cancel_no_status(int fd, const struct iovec *iov, int n);
/* Uncancelable fcntl. */
#define fcntl_not_cancel(fd, cmd, val) \
@@ -70,6 +77,5 @@
# define waitpid_not_cancel(pid, stat_loc, options) \
__waitpid_nocancel (pid, stat_loc, options)
#else
-# define waitpid_not_cancel(pid, stat_loc, options) \
- INLINE_SYSCALL (wait4, 4, pid, stat_loc, options, NULL)
+int waitpid_not_cancel(int pid, int *stat_loc, int options);
#endif
diff -urN glibc-2.3.5.orig/nptl/sysdeps/unix/sysv/linux/not-cancel-close.c glibc-2.3.5.new/nptl/sysdeps/unix/sysv/linux/not-cancel-close.c
--- glibc-2.3.5.orig/nptl/sysdeps/unix/sysv/linux/not-cancel-close.c Wed Dec 31 19:00:00 1969
+++ glibc-2.3.5.new/nptl/sysdeps/unix/sysv/linux/not-cancel-close.c Sat Sep 24 20:10:06 2005
@@ -0,0 +1,2 @@
+
+/* Intentionally empty: this doesn't need to generate anything. */
diff -urN glibc-2.3.5.orig/nptl/sysdeps/unix/sysv/linux/not-cancel-open.c glibc-2.3.5.new/nptl/sysdeps/unix/sysv/linux/not-cancel-open.c
--- glibc-2.3.5.orig/nptl/sysdeps/unix/sysv/linux/not-cancel-open.c Wed Dec 31 19:00:00 1969
+++ glibc-2.3.5.new/nptl/sysdeps/unix/sysv/linux/not-cancel-open.c Sat Sep 24 20:08:54 2005
@@ -0,0 +1,2 @@
+
+/* Intentionally empty: this doesn't need to generate anything. */
diff -urN glibc-2.3.5.orig/nptl/sysdeps/unix/sysv/linux/not-cancel-read.c glibc-2.3.5.new/nptl/sysdeps/unix/sysv/linux/not-cancel-read.c
--- glibc-2.3.5.orig/nptl/sysdeps/unix/sysv/linux/not-cancel-read.c Wed Dec 31 19:00:00 1969
+++ glibc-2.3.5.new/nptl/sysdeps/unix/sysv/linux/not-cancel-read.c Sat Sep 24 20:10:15 2005
@@ -0,0 +1,2 @@
+
+/* Intentionally empty: this doesn't need to generate anything. */
diff -urN glibc-2.3.5.orig/nptl/sysdeps/unix/sysv/linux/not-cancel-waitpid.c glibc-2.3.5.new/nptl/sysdeps/unix/sysv/linux/not-cancel-waitpid.c
--- glibc-2.3.5.orig/nptl/sysdeps/unix/sysv/linux/not-cancel-waitpid.c Wed Dec 31 19:00:00 1969
+++ glibc-2.3.5.new/nptl/sysdeps/unix/sysv/linux/not-cancel-waitpid.c Sat Sep 24 20:55:38 2005
@@ -0,0 +1,31 @@
+/* Uncancelable versions of cancelable interfaces. Linux version.
+ Copyright (C) 2003 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+ Contributed by Ulrich Drepper <drepper@redhat.com>, 2003.
+
+ 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, write to the Free
+ Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+ 02111-1307 USA. */
+
+#include <errno.h>
+#include <sysdep.h>
+#include <not-cancel.h>
+
+
+#if !defined __NR_waitpid
+int waitpid_not_cancel(int pid, int *stat_loc, int options)
+{
+ return INLINE_SYSCALL (wait4, 4, pid, stat_loc, options, NULL);
+}
+#endif
diff -urN glibc-2.3.5.orig/nptl/sysdeps/unix/sysv/linux/not-cancel-write.c glibc-2.3.5.new/nptl/sysdeps/unix/sysv/linux/not-cancel-write.c
--- glibc-2.3.5.orig/nptl/sysdeps/unix/sysv/linux/not-cancel-write.c Wed Dec 31 19:00:00 1969
+++ glibc-2.3.5.new/nptl/sysdeps/unix/sysv/linux/not-cancel-write.c Sat Sep 24 20:10:17 2005
@@ -0,0 +1,2 @@
+
+/* Intentionally empty: this doesn't need to generate anything. */
diff -urN glibc-2.3.5.orig/sysdeps/unix/sysv/linux/Makefile glibc-2.3.5.new/sysdeps/unix/sysv/linux/Makefile
--- glibc-2.3.5.orig/sysdeps/unix/sysv/linux/Makefile Sun Aug 28 07:05:54 2005
+++ glibc-2.3.5.new/sysdeps/unix/sysv/linux/Makefile Sat Sep 24 20:33:42 2005
@@ -13,7 +13,7 @@
ifeq ($(subdir),misc)
sysdep_routines += sysctl clone llseek umount umount2 readahead \
- setfsuid setfsgid makedev
+ setfsuid setfsgid makedev not-cancel-writev
CFLAGS-gethostid.c = -fexceptions
@@ -115,7 +115,7 @@
ifeq ($(subdir),posix)
sysdep_headers += bits/initspin.h
-sysdep_routines += exit-thread
+sysdep_routines += exit-thread not-cancel-waitpid
endif
ifeq ($(subdir),inet)
@@ -137,7 +137,9 @@
endif
ifeq ($(subdir),io)
-sysdep_routines += xstatconv internal_statvfs internal_statvfs64
+sysdep_routines += xstatconv internal_statvfs internal_statvfs64 \
+ not-cancel-open not-cancel-close not-cancel-close-ns \
+ not-cancel-read not-cancel-write
endif
ifeq ($(subdir),elf)
diff -urN glibc-2.3.5.orig/sysdeps/unix/sysv/linux/not-cancel-close-ns.c glibc-2.3.5.new/sysdeps/unix/sysv/linux/not-cancel-close-ns.c
--- glibc-2.3.5.orig/sysdeps/unix/sysv/linux/not-cancel-close-ns.c Wed Dec 31 19:00:00 1969
+++ glibc-2.3.5.new/sysdeps/unix/sysv/linux/not-cancel-close-ns.c Sat Sep 24 20:31:29 2005
@@ -0,0 +1,30 @@
+/* Uncancelable versions of cancelable interfaces. Linux version.
+ Copyright (C) 2003 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+ Contributed by Ulrich Drepper <drepper@redhat.com>, 2003.
+
+ 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, write to the Free
+ Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+ 02111-1307 USA. */
+
+#include <errno.h>
+#include <sysdep.h>
+#include <not-cancel.h>
+
+
+void close_not_cancel_no_status(int fd)
+{
+ INTERNAL_SYSCALL_DECL (err);
+ INTERNAL_SYSCALL (close, err, 1, (fd));
+}
diff -urN glibc-2.3.5.orig/sysdeps/unix/sysv/linux/not-cancel-close.c glibc-2.3.5.new/sysdeps/unix/sysv/linux/not-cancel-close.c
--- glibc-2.3.5.orig/sysdeps/unix/sysv/linux/not-cancel-close.c Wed Dec 31 19:00:00 1969
+++ glibc-2.3.5.new/sysdeps/unix/sysv/linux/not-cancel-close.c Sat Sep 24 20:31:24 2005
@@ -0,0 +1,29 @@
+/* Uncancelable versions of cancelable interfaces. Linux version.
+ Copyright (C) 2003 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+ Contributed by Ulrich Drepper <drepper@redhat.com>, 2003.
+
+ 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, write to the Free
+ Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+ 02111-1307 USA. */
+
+#include <errno.h>
+#include <sysdep.h>
+#include <not-cancel.h>
+
+
+int close_not_cancel(int fd)
+{
+ return INLINE_SYSCALL (close, 1, fd);
+}
diff -urN glibc-2.3.5.orig/sysdeps/unix/sysv/linux/not-cancel-open.c glibc-2.3.5.new/sysdeps/unix/sysv/linux/not-cancel-open.c
--- glibc-2.3.5.orig/sysdeps/unix/sysv/linux/not-cancel-open.c Wed Dec 31 19:00:00 1969
+++ glibc-2.3.5.new/sysdeps/unix/sysv/linux/not-cancel-open.c Tue Sep 20 16:52:54 2005
@@ -0,0 +1,34 @@
+/* Uncancelable versions of cancelable interfaces. Linux version.
+ Copyright (C) 2003 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+ Contributed by Ulrich Drepper <drepper@redhat.com>, 2003.
+
+ 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, write to the Free
+ Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+ 02111-1307 USA. */
+
+#include <errno.h>
+#include <sysdep.h>
+#include <not-cancel.h>
+
+
+int open_not_cancel(const char *name, int flags, int mode)
+{
+ return INLINE_SYSCALL (open, 3, (const char *) (name), (flags), (mode));
+}
+
+int open_not_cancel_2(const char *name, int flags)
+{
+ return INLINE_SYSCALL (open, 2, (const char *) (name), (flags));
+}
diff -urN glibc-2.3.5.orig/sysdeps/unix/sysv/linux/not-cancel-read.c glibc-2.3.5.new/sysdeps/unix/sysv/linux/not-cancel-read.c
--- glibc-2.3.5.orig/sysdeps/unix/sysv/linux/not-cancel-read.c Wed Dec 31 19:00:00 1969
+++ glibc-2.3.5.new/sysdeps/unix/sysv/linux/not-cancel-read.c Tue Sep 20 16:53:18 2005
@@ -0,0 +1,29 @@
+/* Uncancelable versions of cancelable interfaces. Linux version.
+ Copyright (C) 2003 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+ Contributed by Ulrich Drepper <drepper@redhat.com>, 2003.
+
+ 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, write to the Free
+ Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+ 02111-1307 USA. */
+
+#include <errno.h>
+#include <sysdep.h>
+#include <not-cancel.h>
+
+
+int read_not_cancel(int fd, void *buf, int n)
+{
+ return INLINE_SYSCALL (read, 3, (fd), (buf), (n));
+}
diff -urN glibc-2.3.5.orig/sysdeps/unix/sysv/linux/not-cancel-waitpid.c glibc-2.3.5.new/sysdeps/unix/sysv/linux/not-cancel-waitpid.c
--- glibc-2.3.5.orig/sysdeps/unix/sysv/linux/not-cancel-waitpid.c Wed Dec 31 19:00:00 1969
+++ glibc-2.3.5.new/sysdeps/unix/sysv/linux/not-cancel-waitpid.c Tue Sep 20 16:57:25 2005
@@ -0,0 +1,33 @@
+/* Uncancelable versions of cancelable interfaces. Linux version.
+ Copyright (C) 2003 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+ Contributed by Ulrich Drepper <drepper@redhat.com>, 2003.
+
+ 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, write to the Free
+ Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+ 02111-1307 USA. */
+
+#include <errno.h>
+#include <sysdep.h>
+#include <not-cancel.h>
+
+
+int waitpid_not_cancel(int pid, int *stat_loc, int options)
+{
+#ifdef __NR_waitpid
+ return INLINE_SYSCALL (waitpid, 3, pid, stat_loc, options);
+#else
+ return INLINE_SYSCALL (wait4, 4, pid, stat_loc, options, NULL);
+#endif
+}
diff -urN glibc-2.3.5.orig/sysdeps/unix/sysv/linux/not-cancel-write.c glibc-2.3.5.new/sysdeps/unix/sysv/linux/not-cancel-write.c
--- glibc-2.3.5.orig/sysdeps/unix/sysv/linux/not-cancel-write.c Wed Dec 31 19:00:00 1969
+++ glibc-2.3.5.new/sysdeps/unix/sysv/linux/not-cancel-write.c Tue Sep 20 16:53:50 2005
@@ -0,0 +1,29 @@
+/* Uncancelable versions of cancelable interfaces. Linux version.
+ Copyright (C) 2003 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+ Contributed by Ulrich Drepper <drepper@redhat.com>, 2003.
+
+ 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, write to the Free
+ Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+ 02111-1307 USA. */
+
+#include <errno.h>
+#include <sysdep.h>
+#include <not-cancel.h>
+
+
+int write_not_cancel(int fd, const void *buf, int n)
+{
+ return INLINE_SYSCALL (write, 3, (fd), (buf), (n));
+}
diff -urN glibc-2.3.5.orig/sysdeps/unix/sysv/linux/not-cancel-writev.c glibc-2.3.5.new/sysdeps/unix/sysv/linux/not-cancel-writev.c
--- glibc-2.3.5.orig/sysdeps/unix/sysv/linux/not-cancel-writev.c Wed Dec 31 19:00:00 1969
+++ glibc-2.3.5.new/sysdeps/unix/sysv/linux/not-cancel-writev.c Tue Sep 20 16:54:19 2005
@@ -0,0 +1,30 @@
+/* Uncancelable versions of cancelable interfaces. Linux version.
+ Copyright (C) 2003 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+ Contributed by Ulrich Drepper <drepper@redhat.com>, 2003.
+
+ 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, write to the Free
+ Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+ 02111-1307 USA. */
+
+#include <errno.h>
+#include <sysdep.h>
+#include <not-cancel.h>
+
+
+void writev_not_cancel_no_status(int fd, const struct iovec *iov, int n)
+{
+ INTERNAL_SYSCALL_DECL (err);
+ INTERNAL_SYSCALL (writev, err, 3, (fd), (iov), (n));
+}
diff -urN glibc-2.3.5.orig/sysdeps/unix/sysv/linux/not-cancel.h glibc-2.3.5.new/sysdeps/unix/sysv/linux/not-cancel.h
--- glibc-2.3.5.orig/sysdeps/unix/sysv/linux/not-cancel.h Thu Sep 4 10:05:12 2003
+++ glibc-2.3.5.new/sysdeps/unix/sysv/linux/not-cancel.h Sat Sep 24 18:50:56 2005
@@ -20,6 +20,14 @@
#include <sysdep.h>
+
+#if defined NOT_IN_libc && !defined IS_IN_rtld
+
+
+/* The uncancelable versions of read, write, waitpid and close are
+ used by Linuxthreads' libpthread. They are inlined because they
+ are not exported from libc.so. */
+
/* Uncancelable open. */
#define open_not_cancel(name, flags, mode) \
INLINE_SYSCALL (open, 3, (const char *) (name), (flags), (mode))
@@ -57,4 +65,29 @@
#else
# define waitpid_not_cancel(pid, stat_loc, options) \
INLINE_SYSCALL (wait4, 4, pid, stat_loc, options, NULL)
+#endif
+
+
+#else
+
+
+/* Uncancelable versions of open, close, read, write, writev, fcntl,
+ and waitpid. */
+/* Used in libc.so and ld.so (rtld). */
+
+struct iovec;
+
+int open_not_cancel(const char *name, int flags, int mode);
+int open_not_cancel_2(const char *name, int flags);
+int close_not_cancel(int fd);
+void close_not_cancel_no_status(int fd);
+int read_not_cancel(int fd, void *buf, int n);
+int write_not_cancel(int fd, const void *buf, int n);
+void writev_not_cancel_no_status(int fd, const struct iovec *iov, int n);
+int waitpid_not_cancel(int pid, int *stat_loc, int options);
+
+#define fcntl_not_cancel(fd, cmd, val) \
+ __fcntl_nocancel (fd, cmd, val)
+
+
#endif