posix: Implement preadv2 and pwritev2

This patch adds support of preadv2 and pwritev2 which are similar to
preadv/pwritev but with an extra flag argument.  As for preadv/pwritev
both interfaces are added a non-standard GNU API.

For default 'posix' implementation trying to emulate the Linux supported
flags is troublesome:

   * We can not temporary change the file state of the O_DSYNC and O_SYNC
     flags to emulate RWF_{D}SYNC (attempts to change the state of using
     fcntl are silently ignored).

   * IOCB_HIPRI requires the file opened in O_DIRECT and uses an internal
     semantic not provided by any other flag (O_NONBLOCK for instance).

So default sysdeps/posix implementations fails with EOPNOTSUPP for any non
supported flag (which are none currently) calls generic preadv/pwritev.
Basically this implementation supports only preadv2 called as preadv (with
flags sets to 0).

The Linux one uses the preadv2/pwritev2 syscall if defined, otherwise it
call preadv/writev.  Instead of using the previous __ASSUME_* to
unconditionally issue the syscall (and avoid building the fallback routine),
it call pread/write if the preadv2/pwritev2 syscalls fails.  The idea
is just avoid adding another __ASSUME_* and checking each architecture
on every kernel bump and simplify code conditionals.

Checked on x86_64-linux-gnu and on i686-linux-gnu and a check with
run-built-tests=no on aarch64-linux-gnu, alpha-linux-gnu, arm-linux-gnueabihf,
ia64-linux-gnu, m68k-linux-gnu, microblaze-linux-gnu, mips{64,64n32}-linux-gnu,
nios2-linux-gnu, powerpc{64,64le}-linux-gnu, s390{x}-linux-gnu,
sparc{64,v9}-linux-gnu, tile{gx,pro}-linux-gnu, and sh4-linux-gnu (all using
gcc 6.3).

	* NEWS: Add note about pwritev2 and preadv2 inclusion.
	* misc/Makefile (routines): Add preadv2, preadv64v2, pwritev2, and
	pwritev64v2.
	(tests): Add tst-preadvwritev2 and tst-preadvwritev64v2.
	* misc/Versions (GLIBC_2.26): Add preadv2, preadv64v2, pwritev2, and
	pwritev64v2.
	* misc/preadv2.c: New file.
	* misc/preadv64v2.c: Likewise.
	* misc/pwritev2.c: Likewise.
	* misc/pwritev64v2.c: Likewise.
	* misc/tst-preadvwritev2.c: Likewise.
	* misc/tst-preadvwritev64v2.c: Likewise.
	* manual/llio.texi: Add preadv2 and pwritev2 documentation.
	* misc/sys/uio.h [__USE_GNU && !__USE_FILE_OFFSET64] (preadv2): New
	prototype.
	[__USE_GNU && !__USE_FILE_OFFSET64] (pwritev2):	Likewise.
	[__USE_GNU && __USE_FILE_OFFSET64] (preadv64v2): Likewise.
	[__USE_GNU && __USE_FILE_OFFSET64] (pwritev64v2): Likewise.
	* misc/tst-preadvwritev-common.c (PREADV): Define if not defined.
	(PWRITEV): Likewise.
	(do_test_with_offset): Use PREADV and PWRITEV macros and check for
	ENOSYS.
	* nptl/tst-cancel4.c (tf_pwritev2): New test.
	(tf_preadv2): Likewise.
	(tf_fsync): Add tf_pwritev2 and tf_preadv2.
	* sysdeps/posix/preadv2.c: Likewise.
	* sysdeps/posix/preadv64v2.c: Likewise.
	* sysdeps/posix/pwritev2.c: Likewise.
	* sysdeps/posix/pwritev64v2.c: Likewise.
	* sysdeps/unix/sysv/linux/kernel-features.h: Add comment for syscall
	support in kernel.
	* sysdeps/unix/sysv/linux/preadv2.c: Likewise.
	* sysdeps/unix/sysv/linux/preadv64v2.c: Likewise.
	* sysdeps/unix/sysv/linux/pwritev2.c: Likewise.
	* sysdeps/unix/sysv/linux/pwritev64v2.c: Likewise.
	* sysdeps/unix/sysv/linux/preadv.c (preadv): Add libc_hidden_def.
	* sysdeps/unix/sysv/linux/preadv64.c (preadv64): Likewise.
	* sysdeps/unix/sysv/linux/pwritev.c (pwritev): Likewise.
	* sysdeps/unix/sysv/linux/pwritev64.c (pwritev64): Likewise.
	* sysdeps/unix/sysv/linux/bits/uio.h: Add supported preadv2/pwritev2
	support flags on Linux.
	* sysdeps/unix/sysv/linux/aarch64/libc.abilist (GLIBC_2.26): Add
	preadv2, preadv64v2, pwritev2, pwritev64v2.
	* sysdeps/unix/sysv/linux/alpha/libc.abilist (GLIBC_2.26): Likewise.
	* sysdeps/unix/sysv/linux/arm/libc.abilist (GLIBC_2.26): Likewise.
	* sysdeps/unix/sysv/linux/hppa/libc.abilist (GLIBC_2.26): Likewise.
	* sysdeps/unix/sysv/linux/i386/libc.abilist (GLIBC_2.26): Likewise.
	* sysdeps/unix/sysv/linux/ia64/libc.abilist (GLIBC_2.26): Likewise.
	* sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist (GLIBC_2.26):
	Likewise.
	* sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist (GLIBC_2.26):
	Likewise.
	* sysdeps/unix/sysv/linux/microblaze/libc.abilist (GLIBC_2.26):
	Likewise.
	* sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist (GLIBC_2.26):
	Likewise.
	* sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist (GLIBC_2.26):
	Likewise.
	* sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist (GLIBC_2.26):
	Likewise.
	* sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist (GLIBC_2.26):
	Likewise.
	* sysdeps/unix/sysv/linux/nios2/libc.abilist (GLIBC_2.26): Likewise.
	* sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist
	(GLIBC_2.26): Likewise.
	* sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist
	(GLIBC_2.26): Likewise.
	* sysdeps/unix/sysv/linux/powerpc/powerpc64/libc.abilist (GLIBC_2.26):
	Likewise.
	* sysdeps/unix/sysv/linux/powerpc/powerpc64/libc-le.abilist
	(GLIBC_2.26): Likewise.
	* sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist (GLIBC_2.26):
	Likewise.
	* sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist (GLIBC_2.26):
	Likewise.
	* sysdeps/unix/sysv/linux/sh/libc.abilist (GLIBC_2.26): Likewise.
	* sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist (GLIBC_2.26):
	Likewise.
	* sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist (GLIBC_2.26):
	Likewise.
	* sysdeps/sysv/linux/tile/tilegx/tilegx32/libc.abilist (GLIBC_2.26):
	Likewise.
	* sysdeps/sysv/linux/tile/tilegx/tilegx64/libc.abilist (GLIBC_2.26):
	Likewise.
	* sysdeps/unix/sysv/linux/tile/tilepro/libc.abilist (GLIBC_2.26):
	Likewise.
	* sysdeps/unix/sysv/linux/x86_64/64/libc.abilist (GLIBC_2.26):
	Likewise.
	* sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist (GLIBC_2.26):
	Likewise.

10 files changed, 246 insertions, 5 deletions

diff --git a/misc/Makefile b/misc/Makefile
index 2db1fd8..c393fa7 100644
--- a/misc/Makefile
+++ b/misc/Makefile
@@ -39,6 +39,7 @@ headers	:= sys/uio.h bits/uio.h sys/ioctl.h bits/ioctls.h bits/ioctl-types.h \
 
 routines := brk sbrk sstk ioctl \
 	    readv writev preadv preadv64 pwritev pwritev64 \
+	    preadv2 preadv64v2 pwritev2 pwritev64v2 \
 	    setreuid setregid \
 	    seteuid setegid \
 	    getpagesize \
@@ -79,7 +80,8 @@ gpl2lgpl := error.c error.h
 tests := tst-dirname tst-tsearch tst-fdset tst-efgcvt tst-mntent tst-hsearch \
 	 tst-error1 tst-pselect tst-insremque tst-mntent2 bug-hsearch1 \
 	 tst-mntent-blank-corrupt tst-mntent-blank-passno bug18240 \
-	 tst-preadvwritev tst-preadvwritev64 tst-makedev tst-empty
+	 tst-preadvwritev tst-preadvwritev64 tst-makedev tst-empty \
+	 tst-preadvwritev2 tst-preadvwritev64v2
 
 tests-internal := tst-atomic tst-atomic-long
 tests-static := tst-empty
diff --git a/misc/Versions b/misc/Versions
index f2c90ff..bafda78 100644
--- a/misc/Versions
+++ b/misc/Versions
@@ -155,6 +155,9 @@ libc {
   GLIBC_2.25 {
     gnu_dev_major; gnu_dev_minor; gnu_dev_makedev;
   }
+  GLIBC_2.26 {
+    preadv2; preadv64v2; pwritev2; pwritev64v2;
+  }
   GLIBC_PRIVATE {
     __madvise;
     __mktemp;
diff --git a/misc/preadv2.c b/misc/preadv2.c
new file mode 100644
index 0000000..a62dcaa
--- /dev/null
+++ b/misc/preadv2.c
@@ -0,0 +1,30 @@
+/* Default implementation of preadv2.
+   Copyright (C) 2017 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/uio.h>
+
+/* Same as preadv but with an additional flags argument.  */
+ssize_t
+preadv2 (int fd, const struct iovec *vector, int count, off_t offset,
+	 int flags)
+{
+  __set_errno (ENOSYS);
+  return -1;
+}
+
+stub_warning (preadv2)
diff --git a/misc/preadv64v2.c b/misc/preadv64v2.c
new file mode 100644
index 0000000..a802c2f
--- /dev/null
+++ b/misc/preadv64v2.c
@@ -0,0 +1,30 @@
+/* Default implementation of preadv2 (LFS version).
+   Copyright (C) 2017 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/uio.h>
+
+/* Same as preadv64 but with an addional flag argument.  */
+ssize_t
+preadv64v2 (int fd, const struct iovec *vector, int count, off64_t offset,
+	    int flags)
+{
+  __set_errno (ENOSYS);
+  return -1;
+}
+
+stub_warning (preadv64v2)
diff --git a/misc/pwritev2.c b/misc/pwritev2.c
new file mode 100644
index 0000000..b9e0727
--- /dev/null
+++ b/misc/pwritev2.c
@@ -0,0 +1,30 @@
+/* Default implementation of pwritev2.
+   Copyright (C) 2017 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/uio.h>
+
+/* Same as pwritev but with an additional flags argument.  */
+ssize_t
+pwritev2 (int fd, const struct iovec *vector, int count, off_t offset,
+	  int flags)
+{
+  __set_errno (ENOSYS);
+  return -1;
+}
+
+stub_warning (pwritev2)
diff --git a/misc/pwritev64v2.c b/misc/pwritev64v2.c
new file mode 100644
index 0000000..1f874f0
--- /dev/null
+++ b/misc/pwritev64v2.c
@@ -0,0 +1,30 @@
+/* Default implementation of pwritev2 (LFS version).
+   Copyright (C) 2017 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/uio.h>
+
+/* Same as preadv64 but with an addional flag argument.  */
+ssize_t
+pwritev64v2 (int fd, const struct iovec *vector, int count, off64_t offset,
+	     int flags)
+{
+  __set_errno (ENOSYS);
+  return -1;
+}
+
+stub_warning (pwritev64v2)
diff --git a/misc/sys/uio.h b/misc/sys/uio.h
index e80f013..66c22f0 100644
--- a/misc/sys/uio.h
+++ b/misc/sys/uio.h
@@ -76,6 +76,7 @@ extern ssize_t preadv (int __fd, const struct iovec *__iovec, int __count,
    __THROW.  */
 extern ssize_t pwritev (int __fd, const struct iovec *__iovec, int __count,
 			__off_t __offset) __wur;
+
 # else
 #  ifdef __REDIRECT
 extern ssize_t __REDIRECT (preadv, (int __fd, const struct iovec *__iovec,
@@ -117,6 +118,46 @@ extern ssize_t pwritev64 (int __fd, const struct iovec *__iovec, int __count,
 # endif
 #endif	/* Use misc.  */
 
+
+#ifdef __USE_GNU
+# ifndef __USE_FILE_OFFSET64
+/* Same as preadv but with an additional flag argumenti defined at uio.h.  */
+extern ssize_t preadv2 (int __fp, const struct iovec *__iovec, int __count,
+			__off_t __offset, int ___flags) __wur;
+
+/* Same as preadv but with an additional flag argument defined at uio.h.  */
+extern ssize_t pwritev2 (int __fd, const struct iovec *__iodev, int __count,
+			 __off_t __offset, int __flags) __wur;
+
+# else
+#  ifdef __REDIRECT
+extern ssize_t __REDIRECT (pwritev2, (int __fd, const struct iovec *__iovec,
+				      int __count, __off64_t __offset,
+				      int __flags),
+			   pwritev64v2) __wur;
+extern ssize_t __REDIRECT (preadv2, (int __fd, const struct iovec *__iovec,
+				     int __count, __off64_t __offset,
+				     int __flags),
+			   preadv64v2) __wur;
+#  else
+#   define preadv2 preadv64v2
+#   define pwritev2 pwritev64v2
+#  endif
+# endif
+
+# ifdef __USE_LARGEFILE64
+/* Same as preadv but with an additional flag argumenti defined at uio.h.  */
+extern ssize_t preadv64v2 (int __fp, const struct iovec *__iovec,
+			   int __count, __off64_t __offset,
+			   int ___flags) __wur;
+
+/* Same as preadv but with an additional flag argument defined at uio.h.  */
+extern ssize_t pwritev64v2 (int __fd, const struct iovec *__iodev,
+			    int __count, __off64_t __offset,
+			    int __flags) __wur;
+# endif
+#endif /* Use GNU.  */
+
 __END_DECLS
 
 #endif /* sys/uio.h */
diff --git a/misc/tst-preadvwritev-common.c b/misc/tst-preadvwritev-common.c
index 5540dfb..676d495 100644
--- a/misc/tst-preadvwritev-common.c
+++ b/misc/tst-preadvwritev-common.c
@@ -18,6 +18,7 @@
 
 #include <stdio.h>
 #include <stdint.h>
+#include <errno.h>
 #include <string.h>
 #include <sys/uio.h>
 #include <sys/stat.h>
@@ -39,6 +40,16 @@ do_prepare (int argc, char **argv)
 }
 #define PREPARE do_prepare
 
+#ifndef PREADV
+# define PREADV(__fd, __iov, __iovcnt, __offset) \
+  preadv (__fd, __iov, __iovcnt, __offset)
+#endif
+
+#ifndef PWRITEV
+# define PWRITEV(__fd, __iov, __iovcnt, __offset) \
+  pwritev (__fd, __iov, __iovcnt, __offset)
+#endif
+
 static int
 do_test_with_offset (off_t offset)
 {
@@ -58,13 +69,13 @@ do_test_with_offset (off_t offset)
   iov[1].iov_base = buf2;
   iov[1].iov_len = sizeof buf2;
 
-  ret = pwritev (temp_fd, iov, 2, offset);
+  ret = PWRITEV (temp_fd, iov, 2, offset);
   if (ret == -1)
     FAIL_RET ("first pwritev returned -1");
   if (ret != (sizeof buf1 + sizeof buf2))
     FAIL_RET ("first pwritev returned an unexpected value");
 
-  ret = pwritev (temp_fd, iov, 2, sizeof buf1 + sizeof buf2 + offset);
+  ret = PWRITEV (temp_fd, iov, 2, sizeof buf1 + sizeof buf2 + offset);
   if (ret == -1)
     FAIL_RET ("second pwritev returned -1");
   if (ret != (sizeof buf1 + sizeof buf2))
@@ -82,7 +93,7 @@ do_test_with_offset (off_t offset)
   iov[1].iov_len = sizeof buf4;
 
   /* Now read two buffer with 32 and 64 bytes respectively.  */
-  ret = preadv (temp_fd, iov, 2, offset);
+  ret = PREADV (temp_fd, iov, 2, offset);
   if (ret == -1)
     FAIL_RET ("first preadv returned -1");
   if (ret != (sizeof buf3 + sizeof buf4))
@@ -93,7 +104,7 @@ do_test_with_offset (off_t offset)
   if (memcmp (buf2, buf4, sizeof buf2) != 0)
     FAIL_RET ("second buffer from first preadv different than expected");
 
-  ret = preadv (temp_fd, iov, 2, sizeof buf3 + sizeof buf4 + offset);
+  ret = PREADV (temp_fd, iov, 2, sizeof buf3 + sizeof buf4 + offset);
   if (ret == -1)
     FAIL_RET ("second preadv returned -1");
   if (ret != (sizeof buf3 + sizeof buf4))
diff --git a/misc/tst-preadvwritev2.c b/misc/tst-preadvwritev2.c
new file mode 100644
index 0000000..cf36272
--- /dev/null
+++ b/misc/tst-preadvwritev2.c
@@ -0,0 +1,31 @@
+/* Tests for preadv2 and pwritev2.
+   Copyright (C) 2016-2017 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/>.  */
+
+#define PREADV(__fd, __iov, __iovcnt, __offset) \
+  preadv2 (__fd, __iov, __iovcnt, __offset, 0)
+
+#define PWRITEV(__fd, __iov, __iovcnt, __offset) \
+  pwritev2 (__fd, __iov, __iovcnt, __offset, 0)
+
+#include "tst-preadvwritev-common.c"
+
+static int
+do_test (void)
+{
+  return do_test_with_offset (0);
+}
diff --git a/misc/tst-preadvwritev64v2.c b/misc/tst-preadvwritev64v2.c
new file mode 100644
index 0000000..8d0c48e
--- /dev/null
+++ b/misc/tst-preadvwritev64v2.c
@@ -0,0 +1,33 @@
+/* Tests for preadv2 and pwritev2 (LFS version).
+   Copyright (C) 2017 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/>.  */
+
+#define _FILE_OFFSET_BITS 64
+
+#define PREADV(__fd, __iov, __iovcnt, __offset) \
+  preadv2 (__fd, __iov, __iovcnt, __offset, 0)
+
+#define PWRITEV(__fd, __iov, __iovcnt, __offset) \
+  pwritev2 (__fd, __iov, __iovcnt, __offset, 0)
+
+#include "tst-preadvwritev-common.c"
+
+static int
+do_test (void)
+{
+  return do_test_with_offset (0);
+}