88 lines
2.3 KiB
Go
88 lines
2.3 KiB
Go
package system
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import (
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"bytes"
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"os"
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"golang.org/x/sys/unix"
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)
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const (
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// Value is larger than the maximum size allowed
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E2BIG unix.Errno = unix.E2BIG
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// Operation not supported
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ENOTSUP unix.Errno = unix.ENOTSUP
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// Value is too small or too large for maximum size allowed
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EOVERFLOW unix.Errno = unix.EOVERFLOW
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)
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// Lgetxattr retrieves the value of the extended attribute identified by attr
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// and associated with the given path in the file system.
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// Returns a []byte slice if the xattr is set and nil otherwise.
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func Lgetxattr(path string, attr string) ([]byte, error) {
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// Start with a 128 length byte array
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dest := make([]byte, 128)
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sz, errno := unix.Lgetxattr(path, attr, dest)
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for errno == unix.ERANGE {
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// Buffer too small, use zero-sized buffer to get the actual size
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sz, errno = unix.Lgetxattr(path, attr, []byte{})
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if errno != nil {
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return nil, &os.PathError{Op: "lgetxattr", Path: path, Err: errno}
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}
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dest = make([]byte, sz)
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sz, errno = unix.Lgetxattr(path, attr, dest)
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}
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switch {
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case errno == unix.ENODATA:
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return nil, nil
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case errno != nil:
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return nil, &os.PathError{Op: "lgetxattr", Path: path, Err: errno}
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}
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return dest[:sz], nil
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}
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// Lsetxattr sets the value of the extended attribute identified by attr
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// and associated with the given path in the file system.
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func Lsetxattr(path string, attr string, data []byte, flags int) error {
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if err := unix.Lsetxattr(path, attr, data, flags); err != nil {
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return &os.PathError{Op: "lsetxattr", Path: path, Err: err}
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}
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return nil
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}
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// Llistxattr lists extended attributes associated with the given path
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// in the file system.
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func Llistxattr(path string) ([]string, error) {
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dest := make([]byte, 128)
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sz, errno := unix.Llistxattr(path, dest)
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for errno == unix.ERANGE {
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// Buffer too small, use zero-sized buffer to get the actual size
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sz, errno = unix.Llistxattr(path, []byte{})
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if errno != nil {
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return nil, &os.PathError{Op: "llistxattr", Path: path, Err: errno}
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}
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dest = make([]byte, sz)
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sz, errno = unix.Llistxattr(path, dest)
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}
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if errno != nil {
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return nil, &os.PathError{Op: "llistxattr", Path: path, Err: errno}
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}
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var attrs []string
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for _, token := range bytes.Split(dest[:sz], []byte{0}) {
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if len(token) > 0 {
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attrs = append(attrs, string(token))
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}
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}
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return attrs, nil
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}
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