[PATCH v3 2/4] Consolidate lseek/lseek64/llseek implementations

[Adhemerval Zanella <adhemerval dot zanella at linaro dot org>]

Changes from previous version:

  - lseek64 logic to define which syscall to use depends only of
    __NR__llseek and __NR_lseek avaliability (instead of relying on
    __OFF_T_MATCHES_OFF64_T).  This is make new ports that might
    define __OFF_T_MATCHES_OFF64_T, but still use the __NR__llseek
    (such as aarch64 ilp32).

  - Add a guard while defining __NR__llseek only if __NR_llseek is
    also defined.

  - Rebase for new pthread compat wrappers Makefile changes.

--

This patch consolidates all Linux lseek/lseek64/llseek implementation
in on on sysdeps/unix/sysv/linux/lseek{64}.c.  It also removes the llseek
file and instead consolidate the LFS lseek implementation on lseek64.c
as for other LFS symbols implementations.

The general idea is:

  - lseek: ABIs that not define __OFF_T_MATCHES_OFF64_T will preferable
  use __NR__llseek if kernel supports it, otherwise they will use __NR_lseek.
  ABIs that defines __OFF_T_MATCHES_OFF64_T won't produce any symbol.

  - lseek64: ABIs with __OFF_T_MATCHES_OFF64_T will preferable use __NR_lseek
  (since it will use 64-bit arguments without low/high splitting) and
  __NR__llseek if __NR_lseek is not defined (for some ILP32 ports).

  - llseek: files will be removed and symbols will be aliased ot lseek64.

ABI without __OFF_T_MATCHES_OFF64_T and without __NR_llseek (basically MIPS64n32
so far) are covered by building lseek with off_t as expected and lseek64
using __NR_lseek (as expected for off64_t being passed using 64-bit registers).

For this consolidation I mantained the x32 assembly specific implementation
because to correctly fix this it would required both the x32 fix for
{INLINE,INTERNAL}_SYSCALL [1] and a wrapper to correctly subscribe it to
return 64 bits instead of default 32 bits (as for times).  It could a future
cleanup.

It is based on my previous {INTERNAL,INLINE}_SYSCALL_CALL macro [2],
although it is mainly for simplification.

Tested on x86_64, i686, aarch64, armhf, and powerpc64le.

	* nptl/Makefile (pthread-compat-wrappers): Remove llseek and add
	lseek64.
	* sysdeps/unix/sysv/linux/Makefile (sysdeps_routines): Remove llseek.
	* sysdeps/unix/sysv/linux/alpha/Makefile (sysdeps_routines):
	Likewise.
	* sysdeps/unix/sysv/linux/generic/sysdep.h (__NR__llseek): Define iff
	__NR_llseek is defined.
	* sysdeps/unix/sysv/linux/generic/wordsize-32/llseek.c: Remove file.
	* sysdeps/unix/sysv/linux/generic/wordsize-32/lseek.c: Remove file.
	* sysdeps/unix/sysv/linux/mips/mips64/llseek.c: Likewise.
	* sysdeps/unix/sysv/linux/llseek.c: Remove file.
	* sysdeps/unix/sysv/linux/lseek.c: New file.
	* sysdeps/unix/sysv/linux/lseek64.c: Add default Linux implementation.
	* sysdeps/unix/sysv/linux/mips/mips64/syscalls.list: Remove lseek and
	__libc_lseek64 from auto-generation.
	* sysdeps/unix/sysv/linux/wordsize-64/syscalls.list: Likewise.
	* sysdeps/unix/sysv/linux/x86_64/x32/lseek64.S: New file.

[1] https://sourceware.org/ml/libc-alpha/2016-08/msg00443.html
[2] https://sourceware.org/ml/libc-alpha/2016-08/msg00646.html
---
 nptl/Makefile                                      |  2 +-
 sysdeps/unix/sysv/linux/Makefile                   |  2 +-
 sysdeps/unix/sysv/linux/alpha/Makefile             |  2 +-
 sysdeps/unix/sysv/linux/generic/sysdep.h           |  4 +-
 .../unix/sysv/linux/generic/wordsize-32/llseek.c   | 46 ------------------
 .../unix/sysv/linux/generic/wordsize-32/lseek.c    | 38 ---------------
 sysdeps/unix/sysv/linux/llseek.c                   | 46 ------------------
 sysdeps/unix/sysv/linux/lseek.c                    | 56 ++++++++++++++++++++++
 sysdeps/unix/sysv/linux/lseek64.c                  | 54 ++++++++++++++++++++-
 sysdeps/unix/sysv/linux/mips/mips64/llseek.c       |  1 -
 sysdeps/unix/sysv/linux/mips/mips64/syscalls.list  |  2 -
 sysdeps/unix/sysv/linux/wordsize-64/syscalls.list  |  3 --
 sysdeps/unix/sysv/linux/x86_64/x32/lseek64.S       |  1 +
 13 files changed, 116 insertions(+), 141 deletions(-)
 delete mode 100644 sysdeps/unix/sysv/linux/generic/wordsize-32/llseek.c
 delete mode 100644 sysdeps/unix/sysv/linux/generic/wordsize-32/lseek.c
 delete mode 100644 sysdeps/unix/sysv/linux/llseek.c
 create mode 100644 sysdeps/unix/sysv/linux/lseek.c
 delete mode 100644 sysdeps/unix/sysv/linux/mips/mips64/llseek.c
 create mode 100644 sysdeps/unix/sysv/linux/x86_64/x32/lseek64.S

diff --git a/nptl/Makefile b/nptl/Makefile
index e9485df..ee828fe 100644
--- a/nptl/Makefile
+++ b/nptl/Makefile
@@ -38,7 +38,7 @@ shared-only-routines = forward
 pthread-compat-wrappers = \
 		      write read close fcntl accept \
 		      connect recv recvfrom send \
-		      sendto fsync lseek llseek \
+		      sendto fsync lseek lseek64 \
 		      msync nanosleep open open64 pause \
 		      pread pread64 pwrite pwrite64 \
 		      tcdrain wait waitpid msgrcv msgsnd \
diff --git a/sysdeps/unix/sysv/linux/Makefile b/sysdeps/unix/sysv/linux/Makefile
index 9a0423e..16a61cb 100644
--- a/sysdeps/unix/sysv/linux/Makefile
+++ b/sysdeps/unix/sysv/linux/Makefile
@@ -14,7 +14,7 @@ endif
 ifeq ($(subdir),misc)
 include $(firstword $(wildcard $(sysdirs:=/sysctl.mk)))
 
-sysdep_routines += clone llseek umount umount2 readahead \
+sysdep_routines += clone umount umount2 readahead \
 		   setfsuid setfsgid epoll_pwait signalfd \
 		   eventfd eventfd_read eventfd_write prlimit \
 		   personality
diff --git a/sysdeps/unix/sysv/linux/alpha/Makefile b/sysdeps/unix/sysv/linux/alpha/Makefile
index 1e858ce..45941b0 100644
--- a/sysdeps/unix/sysv/linux/alpha/Makefile
+++ b/sysdeps/unix/sysv/linux/alpha/Makefile
@@ -10,7 +10,7 @@ ifeq ($(subdir),misc)
 sysdep_headers += alpha/ptrace.h alpha/regdef.h sys/io.h
 
 sysdep_routines += ieee_get_fp_control ieee_set_fp_control \
-		   ioperm llseek
+		   ioperm
 
 # Support old timeval32 entry points
 sysdep_routines += osf_select osf_gettimeofday osf_settimeofday \
diff --git a/sysdeps/unix/sysv/linux/generic/sysdep.h b/sysdeps/unix/sysv/linux/generic/sysdep.h
index b0422ff..6d379cc 100644
--- a/sysdeps/unix/sysv/linux/generic/sysdep.h
+++ b/sysdeps/unix/sysv/linux/generic/sysdep.h
@@ -22,7 +22,9 @@
 #include <sysdeps/unix/sysv/linux/sysdep.h>
 
 /* Provide the common name to allow more code reuse.  */
-#define __NR__llseek __NR_llseek
+#ifdef __NR_llseek
+# define __NR__llseek __NR_llseek
+#endif
 
 #if __WORDSIZE == 64
 /* By defining the older names, glibc will build syscall wrappers for
diff --git a/sysdeps/unix/sysv/linux/generic/wordsize-32/llseek.c b/sysdeps/unix/sysv/linux/generic/wordsize-32/llseek.c
deleted file mode 100644
index 458964c..0000000
--- a/sysdeps/unix/sysv/linux/generic/wordsize-32/llseek.c
+++ /dev/null
@@ -1,46 +0,0 @@
-/* Copyright (C) 2011-2016 Free Software Foundation, Inc.
-   This file is part of the GNU C Library.
-   Contributed by Chris Metcalf <cmetcalf@tilera.com>, 2011.
-
-   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 <errno.h>
-#include <sys/types.h>
-
-#include <sysdep.h>
-#include <sys/syscall.h>
-
-/* Seek to OFFSET on FD, starting from WHENCE.  */
-extern loff_t __llseek (int fd, loff_t offset, int whence);
-
-loff_t
-__llseek (int fd, loff_t offset, int whence)
-{
-  loff_t retval;
-
-  return (loff_t) (INLINE_SYSCALL (_llseek, 5, fd, (off_t) (offset >> 32),
-				   (off_t) (offset & 0xffffffff),
-				   &retval, whence) ?: retval);
-}
-weak_alias (__llseek, llseek)
-strong_alias (__llseek, __libc_lseek64)
-strong_alias (__llseek, __lseek64)
-weak_alias (__llseek, lseek64)
-
-/* llseek doesn't have a prototype.  Since the second parameter is a
-   64bit type, this results in wrong behaviour if no prototype is
-   provided.  */
-link_warning (llseek, "\
-the `llseek' function may be dangerous; use `lseek64' instead.")
diff --git a/sysdeps/unix/sysv/linux/generic/wordsize-32/lseek.c b/sysdeps/unix/sysv/linux/generic/wordsize-32/lseek.c
deleted file mode 100644
index dbf0b26..0000000
--- a/sysdeps/unix/sysv/linux/generic/wordsize-32/lseek.c
+++ /dev/null
@@ -1,38 +0,0 @@
-/* Copyright (C) 2011-2016 Free Software Foundation, Inc.
-   This file is part of the GNU C Library.
-   Contributed by Chris Metcalf <cmetcalf@tilera.com>, 2011.
-
-   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 <errno.h>
-#include <unistd.h>
-#include <sys/types.h>
-
-#include <sysdep.h>
-#include <sys/syscall.h>
-
-#include "overflow.h"
-
-off_t
-__lseek (int fd, off_t offset, int whence)
-{
-  loff_t res;
-  int rc = INLINE_SYSCALL (_llseek, 5, fd, (off_t) (offset >> 31),
-                           (off_t) offset, &res, whence);
-  return rc ?: lseek_overflow (res);
-}
-libc_hidden_def (__lseek)
-weak_alias (__lseek, lseek)
-strong_alias (__lseek, __libc_lseek)
diff --git a/sysdeps/unix/sysv/linux/llseek.c b/sysdeps/unix/sysv/linux/llseek.c
deleted file mode 100644
index b6f3ea5..0000000
--- a/sysdeps/unix/sysv/linux/llseek.c
+++ /dev/null
@@ -1,46 +0,0 @@
-/* Long-long seek operation.
-   Copyright (C) 1996-2016 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 <errno.h>
-#include <sys/types.h>
-
-#include <sysdep.h>
-#include <sys/syscall.h>
-
-/* Seek to OFFSET on FD, starting from WHENCE.  */
-extern loff_t __llseek (int fd, loff_t offset, int whence);
-
-loff_t
-__llseek (int fd, loff_t offset, int whence)
-{
-  loff_t retval;
-
-  return (loff_t) (INLINE_SYSCALL (_llseek, 5, fd, (off_t) (offset >> 32),
-				   (off_t) (offset & 0xffffffff),
-				   &retval, whence) ?: retval);
-}
-weak_alias (__llseek, llseek)
-strong_alias (__llseek, __libc_lseek64)
-strong_alias (__llseek, __lseek64)
-weak_alias (__llseek, lseek64)
-
-/* llseek doesn't have a prototype.  Since the second parameter is a
-   64bit type, this results in wrong behaviour if no prototype is
-   provided.  */
-link_warning (llseek, "\
-the `llseek' function may be dangerous; use `lseek64' instead.")
diff --git a/sysdeps/unix/sysv/linux/lseek.c b/sysdeps/unix/sysv/linux/lseek.c
new file mode 100644
index 0000000..568df01
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/lseek.c
@@ -0,0 +1,56 @@
+/* Copyright (C) 2016 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 <unistd.h>
+#include <stdint.h>
+#include <sys/types.h>
+#include <sysdep.h>
+#include <errno.h>
+
+#ifndef __OFF_T_MATCHES_OFF64_T
+
+/* Test for overflows of structures where we ask the kernel to fill them
+   in with standard 64-bit syscalls but return them through APIs that
+   only expose the low 32 bits of some fields.  */
+
+static inline off_t lseek_overflow (loff_t res)
+{
+  off_t retval = (off_t) res;
+  if (retval == res)
+    return retval;
+
+  __set_errno (EOVERFLOW);
+  return (off_t) -1;
+}
+
+off_t
+__lseek (int fd, off_t offset, int whence)
+{
+# ifdef __NR__llseek
+  loff_t res;
+  int rc = INLINE_SYSCALL_CALL (_llseek, fd,
+				(long) (((uint64_t) (offset)) >> 32),
+				(long) offset, &res, whence);
+  return rc ?: lseek_overflow (res);
+# else
+  return INLINE_SYSCALL_CALL (lseek, fd, offset, whence);
+# endif
+}
+libc_hidden_def (__lseek)
+weak_alias (__lseek, lseek)
+strong_alias (__lseek, __libc_lseek)
+#endif /* __OFF_T_MATCHES_OFF64_T  */
diff --git a/sysdeps/unix/sysv/linux/lseek64.c b/sysdeps/unix/sysv/linux/lseek64.c
index d81e98f..7e1ff23 100644
--- a/sysdeps/unix/sysv/linux/lseek64.c
+++ b/sysdeps/unix/sysv/linux/lseek64.c
@@ -1 +1,53 @@
-/* We don't need a definition since the llseek function is what we need.  */
+/* Copyright (C) 2016 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 <unistd.h>
+#include <stdint.h>
+#include <sys/types.h>
+#include <sysdep.h>
+#include <errno.h>
+
+off64_t
+__lseek64 (int fd, off64_t offset, int whence)
+{
+#ifdef __NR__llseek
+  loff_t res;
+  int rc = INLINE_SYSCALL_CALL (_llseek, fd,
+				(long) (((uint64_t) (offset)) >> 32),
+				(long) offset, &res, whence);
+  return rc ?: res;
+#else
+  return INLINE_SYSCALL_CALL (lseek, fd, offset, whence);
+#endif
+}
+
+#ifdef  __OFF_T_MATCHES_OFF64_T
+weak_alias (__lseek64, lseek)
+weak_alias (__lseek64, __lseek)
+strong_alias (__lseek64, __libc_lseek)
+libc_hidden_def (__lseek)
+#endif
+
+strong_alias (__lseek64, __libc_lseek64)
+weak_alias (__lseek64, lseek64)
+
+/* llseek doesn't have a prototype.  Since the second parameter is a
+   64bit type, this results in wrong behaviour if no prototype is
+   provided.  */
+weak_alias (__lseek64, llseek)
+link_warning (llseek, "\
+the `llseek' function may be dangerous; use `lseek64' instead.")
diff --git a/sysdeps/unix/sysv/linux/mips/mips64/llseek.c b/sysdeps/unix/sysv/linux/mips/mips64/llseek.c
deleted file mode 100644
index 24013a8..0000000
--- a/sysdeps/unix/sysv/linux/mips/mips64/llseek.c
+++ /dev/null
@@ -1 +0,0 @@
-/* lseek() is 64-bit capable already.  */
diff --git a/sysdeps/unix/sysv/linux/mips/mips64/syscalls.list b/sysdeps/unix/sysv/linux/mips/mips64/syscalls.list
index 66cc687..d2d851e 100644
--- a/sysdeps/unix/sysv/linux/mips/mips64/syscalls.list
+++ b/sysdeps/unix/sysv/linux/mips/mips64/syscalls.list
@@ -1,7 +1,5 @@
 # File name	Caller	Syscall name	Args	Strong name	Weak names
 
-lseek		-	lseek		i:iii	__libc_lseek	__lseek lseek __llseek llseek __libc_lseek64 __lseek64 lseek64
-
 ftruncate	-	ftruncate	i:ii	__ftruncate	ftruncate ftruncate64 __ftruncate64
 truncate	-	truncate	i:si	truncate	truncate64
 
diff --git a/sysdeps/unix/sysv/linux/wordsize-64/syscalls.list b/sysdeps/unix/sysv/linux/wordsize-64/syscalls.list
index 2eb9419..3f3569f 100644
--- a/sysdeps/unix/sysv/linux/wordsize-64/syscalls.list
+++ b/sysdeps/unix/sysv/linux/wordsize-64/syscalls.list
@@ -1,8 +1,5 @@
 # File name	Caller	Syscall name	# args	Strong name	Weak names
 
-# Whee! 64-bit systems naturally implement llseek.
-llseek		EXTRA	lseek		i:iii	__libc_lseek	__lseek lseek __libc_lseek64 __llseek llseek __lseek64 lseek64
-lseek		llseek	-
 fstatfs		-	fstatfs		i:ip	__fstatfs	fstatfs fstatfs64 __fstatfs64
 statfs		-	statfs		i:sp	__statfs	statfs statfs64
 mmap		-	mmap		b:aniiii __mmap		mmap __mmap64 mmap64
diff --git a/sysdeps/unix/sysv/linux/x86_64/x32/lseek64.S b/sysdeps/unix/sysv/linux/x86_64/x32/lseek64.S
new file mode 100644
index 0000000..d81e98f
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/x86_64/x32/lseek64.S
@@ -0,0 +1 @@
+/* We don't need a definition since the llseek function is what we need.  */
-- 
2.7.4