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//go:build aix || dragonfly || freebsd || (js && wasm) || linux || netbsd || openbsd || solaris
package dirent
import (
"os"
"runtime"
"syscall"
"unsafe"
)
// readInt returns the size-bytes unsigned integer in native byte order at offset off.
func readInt(b []byte, off, size uintptr) (u uint64, ok bool) {
if len(b) < int(off+size) {
return 0, false
}
if isBigEndian {
return readIntBE(b[off:], size), true
}
return readIntLE(b[off:], size), true
}
func readIntBE(b []byte, size uintptr) uint64 {
switch size {
case 1:
return uint64(b[0])
case 2:
_ = b[1] // bounds check hint to compiler; see golang.org/issue/14808
return uint64(b[1]) | uint64(b[0])<<8
case 4:
_ = b[3] // bounds check hint to compiler; see golang.org/issue/14808
return uint64(b[3]) | uint64(b[2])<<8 | uint64(b[1])<<16 | uint64(b[0])<<24
case 8:
_ = b[7] // bounds check hint to compiler; see golang.org/issue/14808
return uint64(b[7]) | uint64(b[6])<<8 | uint64(b[5])<<16 | uint64(b[4])<<24 |
uint64(b[3])<<32 | uint64(b[2])<<40 | uint64(b[1])<<48 | uint64(b[0])<<56
default:
panic("syscall: readInt with unsupported size")
}
}
func readIntLE(b []byte, size uintptr) uint64 {
switch size {
case 1:
return uint64(b[0])
case 2:
_ = b[1] // bounds check hint to compiler; see golang.org/issue/14808
return uint64(b[0]) | uint64(b[1])<<8
case 4:
_ = b[3] // bounds check hint to compiler; see golang.org/issue/14808
return uint64(b[0]) | uint64(b[1])<<8 | uint64(b[2])<<16 | uint64(b[3])<<24
case 8:
_ = b[7] // bounds check hint to compiler; see golang.org/issue/14808
return uint64(b[0]) | uint64(b[1])<<8 | uint64(b[2])<<16 | uint64(b[3])<<24 |
uint64(b[4])<<32 | uint64(b[5])<<40 | uint64(b[6])<<48 | uint64(b[7])<<56
default:
panic("syscall: readInt with unsupported size")
}
}
const InvalidMode = os.FileMode(1<<32 - 1)
func Parse(buf []byte) (consumed int, name string, typ os.FileMode) {
reclen, ok := direntReclen(buf)
if !ok || reclen > uint64(len(buf)) {
// WARN: this is a hard error because we consumed 0 bytes
// and not stopping here could lead to an infinite loop.
return 0, "", InvalidMode
}
consumed = int(reclen)
rec := buf[:reclen]
ino, ok := direntIno(rec)
if !ok {
return consumed, "", InvalidMode
}
// When building to wasip1, the host runtime might be running on Windows
// or might expose a remote file system which does not have the concept
// of inodes. Therefore, we cannot make the assumption that it is safe
// to skip entries with zero inodes.
if ino == 0 && runtime.GOOS != "wasip1" {
return consumed, "", InvalidMode
}
typ = direntType(buf)
const namoff = uint64(unsafe.Offsetof(syscall.Dirent{}.Name))
namlen, ok := direntNamlen(rec)
if !ok || namoff+namlen > uint64(len(rec)) {
return consumed, "", InvalidMode
}
namebuf := rec[namoff : namoff+namlen]
for i, c := range namebuf {
if c == 0 {
namebuf = namebuf[:i]
break
}
}
// Check for useless names before allocating a string.
if string(namebuf) == "." {
name = "."
} else if string(namebuf) == ".." {
name = ".."
} else {
name = string(namebuf)
}
return consumed, name, typ
}
|
