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	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.
		
	
		
			
				
	
	
		
			123 lines
		
	
	
		
			3.6 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			123 lines
		
	
	
		
			3.6 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
| /* Common definitions for preadv and pwritev.
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|    Copyright (C) 2016-2017 Free Software Foundation, Inc.
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|    This file is part of the GNU C Library.
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| 
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|    The GNU C Library is free software; you can redistribute it and/or
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|    modify it under the terms of the GNU Lesser General Public
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|    License as published by the Free Software Foundation; either
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|    version 2.1 of the License, or (at your option) any later version.
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| 
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|    The GNU C Library is distributed in the hope that it will be useful,
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|    but WITHOUT ANY WARRANTY; without even the implied warranty of
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|    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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|    Lesser General Public License for more details.
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| 
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|    You should have received a copy of the GNU Lesser General Public
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|    License along with the GNU C Library; if not, see
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|    <http://www.gnu.org/licenses/>.  */
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| 
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| #include <stdio.h>
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| #include <stdint.h>
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| #include <errno.h>
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| #include <string.h>
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| #include <sys/uio.h>
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| #include <sys/stat.h>
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| 
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| #include <support/check.h>
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| #include <support/temp_file.h>
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| 
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| static char *temp_filename;
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| static int temp_fd;
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| 
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| static int do_test (void);
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| 
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| static void
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| do_prepare (int argc, char **argv)
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| {
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|   temp_fd = create_temp_file ("tst-preadvwritev.", &temp_filename);
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|   if (temp_fd == -1)
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|     FAIL_EXIT1 ("cannot create temporary file");
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| }
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| #define PREPARE do_prepare
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| 
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| #ifndef PREADV
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| # define PREADV(__fd, __iov, __iovcnt, __offset) \
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|   preadv (__fd, __iov, __iovcnt, __offset)
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| #endif
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| 
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| #ifndef PWRITEV
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| # define PWRITEV(__fd, __iov, __iovcnt, __offset) \
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|   pwritev (__fd, __iov, __iovcnt, __offset)
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| #endif
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| 
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| static int
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| do_test_with_offset (off_t offset)
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| {
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|   struct iovec iov[2];
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|   ssize_t ret;
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| 
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|   char buf1[32];
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|   char buf2[64];
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| 
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|   memset (buf1, 0xf0, sizeof buf1);
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|   memset (buf2, 0x0f, sizeof buf2);
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| 
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|   /* Write two buffer with 32 and 64 bytes respectively.  */
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|   memset (iov, 0, sizeof iov);
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|   iov[0].iov_base = buf1;
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|   iov[0].iov_len = sizeof buf1;
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|   iov[1].iov_base = buf2;
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|   iov[1].iov_len = sizeof buf2;
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| 
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|   ret = PWRITEV (temp_fd, iov, 2, offset);
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|   if (ret == -1)
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|     FAIL_RET ("first pwritev returned -1");
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|   if (ret != (sizeof buf1 + sizeof buf2))
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|     FAIL_RET ("first pwritev returned an unexpected value");
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| 
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|   ret = PWRITEV (temp_fd, iov, 2, sizeof buf1 + sizeof buf2 + offset);
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|   if (ret == -1)
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|     FAIL_RET ("second pwritev returned -1");
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|   if (ret != (sizeof buf1 + sizeof buf2))
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|     FAIL_RET ("second pwritev returned an unexpected value");
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| 
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|   char buf3[32];
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|   char buf4[64];
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| 
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|   memset (buf3, 0x0f, sizeof buf3);
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|   memset (buf4, 0xf0, sizeof buf4);
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| 
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|   iov[0].iov_base = buf3;
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|   iov[0].iov_len = sizeof buf3;
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|   iov[1].iov_base = buf4;
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|   iov[1].iov_len = sizeof buf4;
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| 
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|   /* Now read two buffer with 32 and 64 bytes respectively.  */
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|   ret = PREADV (temp_fd, iov, 2, offset);
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|   if (ret == -1)
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|     FAIL_RET ("first preadv returned -1");
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|   if (ret != (sizeof buf3 + sizeof buf4))
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|     FAIL_RET ("first preadv returned an unexpected value");
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| 
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|   if (memcmp (buf1, buf3, sizeof buf1) != 0)
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|     FAIL_RET ("first buffer from first preadv different than expected");
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|   if (memcmp (buf2, buf4, sizeof buf2) != 0)
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|     FAIL_RET ("second buffer from first preadv different than expected");
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| 
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|   ret = PREADV (temp_fd, iov, 2, sizeof buf3 + sizeof buf4 + offset);
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|   if (ret == -1)
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|     FAIL_RET ("second preadv returned -1");
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|   if (ret != (sizeof buf3 + sizeof buf4))
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|     FAIL_RET ("second preadv returned an unexpected value");
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| 
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|   /* And compare the buffers read and written to check if there are equal.  */
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|   if (memcmp (buf1, buf3, sizeof buf1) != 0)
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|     FAIL_RET ("first buffer from second preadv different than expected");
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|   if (memcmp (buf2, buf4, sizeof buf2) != 0)
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|     FAIL_RET ("second buffer from second preadv different than expected");
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| 
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|   return 0;
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| }
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| 
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| #include <support/test-driver.c>
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