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	2ab8c12fc8
	
	
	
		
			
			Calling link(2) with a symlink as the target will cause FreeBSD to
attempt to create a new hard link pointing to the target of the symlink
rather than a hardlink to the symlink itself. By contrast, Linux creates
a hardlink to the symlink.
Use linkat(2) instead, which accepts a flag controlling this behavior.
If linkat(2) is called with AT_SYMLINK_FOLLOW, it will behave the same
as link(2).  If linkat(2) is called without AT_SYMLINK_FOLLOW, it will
behave the same as Linux's link(2) instead.
See FreeBSD's implementation of ln(1), which uses linkat(2) and controls
this behavior by way of the -P and -L flags:
3003117253/bin/ln/ln.c (L342-L343)
Signed-off-by: Samuel Karp <me@samuelkarp.com>
		
	
		
			
				
	
	
		
			83 lines
		
	
	
		
			3.1 KiB
		
	
	
	
		
			Go
		
	
	
	
	
	
			
		
		
	
	
			83 lines
		
	
	
		
			3.1 KiB
		
	
	
	
		
			Go
		
	
	
	
	
	
| /*
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|    Copyright The containerd Authors.
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| 
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|    Licensed under the Apache License, Version 2.0 (the "License");
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|    you may not use this file except in compliance with the License.
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|    You may obtain a copy of the License at
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| 
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|        http://www.apache.org/licenses/LICENSE-2.0
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| 
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|    Unless required by applicable law or agreed to in writing, software
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|    distributed under the License is distributed on an "AS IS" BASIS,
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|    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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|    See the License for the specific language governing permissions and
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|    limitations under the License.
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| */
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| 
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| package archive
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| 
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| import (
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| 	"os"
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| 	"syscall"
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| 
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| 	"golang.org/x/sys/unix"
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| )
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| 
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| func link(oldname, newname string) error {
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| 	e := ignoringEINTR(func() error {
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| 		return unix.Linkat(unix.AT_FDCWD, oldname, unix.AT_FDCWD, newname, 0)
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| 	})
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| 	if e != nil {
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| 		return &os.LinkError{Op: "link", Old: oldname, New: newname, Err: e}
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| 	}
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| 	return nil
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| }
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| 
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| // The following contents were copied from Go 1.18.2.
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| // Use of this source code is governed by the following
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| // BSD-style license:
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| //
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| // Copyright (c) 2009 The Go Authors. All rights reserved.
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| //
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| // Redistribution and use in source and binary forms, with or without
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| // modification, are permitted provided that the following conditions are
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| // met:
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| //
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| //   * Redistributions of source code must retain the above copyright
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| // notice, this list of conditions and the following disclaimer.
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| //   * Redistributions in binary form must reproduce the above
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| // copyright notice, this list of conditions and the following disclaimer
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| // in the documentation and/or other materials provided with the
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| // distribution.
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| //   * Neither the name of Google Inc. nor the names of its
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| // contributors may be used to endorse or promote products derived from
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| // this software without specific prior written permission.
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| //
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| // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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| // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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| // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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| // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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| // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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| // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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| // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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| // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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| // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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| // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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| // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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| 
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| // ignoringEINTR makes a function call and repeats it if it returns an
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| // EINTR error. This appears to be required even though we install all
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| // signal handlers with SA_RESTART: see #22838, #38033, #38836, #40846.
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| // Also #20400 and #36644 are issues in which a signal handler is
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| // installed without setting SA_RESTART. None of these are the common case,
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| // but there are enough of them that it seems that we can't avoid
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| // an EINTR loop.
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| func ignoringEINTR(fn func() error) error {
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| 	for {
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| 		err := fn()
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| 		if err != syscall.EINTR {
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| 			return err
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| 		}
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| 	}
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| }
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