63 lines
1.8 KiB
Go
63 lines
1.8 KiB
Go
package system
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import (
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"syscall"
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"unsafe"
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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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// It will returns a nil slice and nil error if the xattr is not set.
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func Lgetxattr(path string, attr string) ([]byte, error) {
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pathBytes, err := syscall.BytePtrFromString(path)
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if err != nil {
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return nil, err
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}
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attrBytes, err := syscall.BytePtrFromString(attr)
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if err != nil {
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return nil, err
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}
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dest := make([]byte, 128)
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destBytes := unsafe.Pointer(&dest[0])
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sz, _, errno := syscall.Syscall6(syscall.SYS_LGETXATTR, uintptr(unsafe.Pointer(pathBytes)), uintptr(unsafe.Pointer(attrBytes)), uintptr(destBytes), uintptr(len(dest)), 0, 0)
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if errno == syscall.ENODATA {
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return nil, nil
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}
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if errno == syscall.ERANGE {
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dest = make([]byte, sz)
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destBytes := unsafe.Pointer(&dest[0])
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sz, _, errno = syscall.Syscall6(syscall.SYS_LGETXATTR, uintptr(unsafe.Pointer(pathBytes)), uintptr(unsafe.Pointer(attrBytes)), uintptr(destBytes), uintptr(len(dest)), 0, 0)
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}
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if errno != 0 {
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return nil, errno
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}
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return dest[:sz], nil
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}
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var _zero uintptr
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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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pathBytes, err := syscall.BytePtrFromString(path)
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if err != nil {
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return err
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}
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attrBytes, err := syscall.BytePtrFromString(attr)
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if err != nil {
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return err
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}
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var dataBytes unsafe.Pointer
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if len(data) > 0 {
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dataBytes = unsafe.Pointer(&data[0])
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} else {
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dataBytes = unsafe.Pointer(&_zero)
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}
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_, _, errno := syscall.Syscall6(syscall.SYS_LSETXATTR, uintptr(unsafe.Pointer(pathBytes)), uintptr(unsafe.Pointer(attrBytes)), uintptr(dataBytes), uintptr(len(data)), uintptr(flags), 0)
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if errno != 0 {
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return errno
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}
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return nil
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}
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