github.com/hanwen/go-fuse@v1.0.0/fuse/pathfs/syscall_linux.go (about)

     1  // Copyright 2016 the Go-FUSE Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package pathfs
     6  
     7  import (
     8  	"bytes"
     9  	"syscall"
    10  	"unsafe"
    11  )
    12  
    13  var _zero uintptr
    14  
    15  func getXAttr(path string, attr string, dest []byte) (value []byte, err error) {
    16  	sz, err := sysGetxattr(path, attr, dest)
    17  	for sz > cap(dest) && err == nil {
    18  		dest = make([]byte, sz)
    19  		sz, err = sysGetxattr(path, attr, dest)
    20  	}
    21  
    22  	if err != nil {
    23  		return nil, err
    24  	}
    25  
    26  	return dest[:sz], err
    27  }
    28  
    29  func listXAttr(path string) (attributes []string, err error) {
    30  	dest := make([]byte, 0)
    31  	sz, err := sysListxattr(path, dest)
    32  	if err != nil {
    33  		return nil, err
    34  	}
    35  
    36  	for sz > cap(dest) && err == nil {
    37  		dest = make([]byte, sz)
    38  		sz, err = sysListxattr(path, dest)
    39  	}
    40  
    41  	if sz == 0 {
    42  		return nil, err
    43  	}
    44  
    45  	// -1 to drop the final empty slice.
    46  	dest = dest[:sz-1]
    47  	attributesBytes := bytes.Split(dest, []byte{0})
    48  	attributes = make([]string, len(attributesBytes))
    49  	for i, v := range attributesBytes {
    50  		attributes[i] = string(v)
    51  	}
    52  	return attributes, err
    53  }
    54  
    55  // Below is cut & paste from std lib syscall, so gccgo 4.8.1 can
    56  // compile this too.
    57  func sysGetxattr(path string, attr string, dest []byte) (sz int, err error) {
    58  	var _p0 *byte
    59  	_p0, err = syscall.BytePtrFromString(path)
    60  	if err != nil {
    61  		return
    62  	}
    63  	var _p1 *byte
    64  	_p1, err = syscall.BytePtrFromString(attr)
    65  	if err != nil {
    66  		return
    67  	}
    68  	var _p2 unsafe.Pointer
    69  	if len(dest) > 0 {
    70  		_p2 = unsafe.Pointer(&dest[0])
    71  	} else {
    72  		_p2 = unsafe.Pointer(&_zero)
    73  	}
    74  	r0, _, e1 := syscall.Syscall6(syscall.SYS_GETXATTR, uintptr(unsafe.Pointer(_p0)), uintptr(unsafe.Pointer(_p1)), uintptr(_p2), uintptr(len(dest)), 0, 0)
    75  	sz = int(r0)
    76  	if e1 != 0 {
    77  		err = e1
    78  	}
    79  	return
    80  }
    81  
    82  func sysRemovexattr(path string, attr string) (err error) {
    83  	var _p0 *byte
    84  	_p0, err = syscall.BytePtrFromString(path)
    85  	if err != nil {
    86  		return
    87  	}
    88  	var _p1 *byte
    89  	_p1, err = syscall.BytePtrFromString(attr)
    90  	if err != nil {
    91  		return
    92  	}
    93  	_, _, e1 := syscall.Syscall(syscall.SYS_REMOVEXATTR, uintptr(unsafe.Pointer(_p0)), uintptr(unsafe.Pointer(_p1)), 0)
    94  	if e1 != 0 {
    95  		err = e1
    96  	}
    97  	return
    98  }
    99  
   100  func sysListxattr(path string, dest []byte) (sz int, err error) {
   101  	var _p0 *byte
   102  	_p0, err = syscall.BytePtrFromString(path)
   103  	if err != nil {
   104  		return
   105  	}
   106  	var _p1 unsafe.Pointer
   107  	if len(dest) > 0 {
   108  		_p1 = unsafe.Pointer(&dest[0])
   109  	} else {
   110  		_p1 = unsafe.Pointer(&_zero)
   111  	}
   112  	r0, _, e1 := syscall.Syscall(syscall.SYS_LISTXATTR, uintptr(unsafe.Pointer(_p0)), uintptr(_p1), uintptr(len(dest)))
   113  	sz = int(r0)
   114  	if e1 != 0 {
   115  		err = e1
   116  	}
   117  	return
   118  }
   119  
   120  func sysSetxattr(path string, attr string, val []byte, flag int) error {
   121  	return syscall.Setxattr(path, attr, val, flag)
   122  }
   123  
   124  const _AT_SYMLINK_NOFOLLOW = 0x100
   125  
   126  // Linux kernel syscall utimensat(2)
   127  //
   128  // Needed to implement SetAttr on symlinks correctly as only utimensat provides
   129  // AT_SYMLINK_NOFOLLOW.
   130  func sysUtimensat(dirfd int, pathname string, times *[2]syscall.Timespec, flags int) (err error) {
   131  
   132  	// Null-terminated version of pathname
   133  	p0, err := syscall.BytePtrFromString(pathname)
   134  	if err != nil {
   135  		return err
   136  	}
   137  
   138  	_, _, e1 := syscall.Syscall6(syscall.SYS_UTIMENSAT,
   139  		uintptr(dirfd), uintptr(unsafe.Pointer(p0)), uintptr(unsafe.Pointer(times)), uintptr(flags), 0, 0)
   140  	if e1 != 0 {
   141  		err = syscall.Errno(e1)
   142  	}
   143  	return
   144  }