// Copyright 2010 The Go Authors. All rights reserved. // Use of this source code is governed by a BSD-style // license that can be found in the LICENSE-GO file. // Modifications Copyright 2020 The Libc Authors. All rights reserved. // Use of this source code is governed by a BSD-style // license that can be found in the LICENSE file. //go:build !(linux && (amd64 || loong64)) package libc // import "modernc.org/libc" import ( "fmt" "os" "sync" "time" "unsafe" "golang.org/x/sys/unix" "modernc.org/libc/errno" "modernc.org/libc/fcntl" ) // Random number state. // We generate random temporary file names so that there's a good // chance the file doesn't exist yet - keeps the number of tries in // TempFile to a minimum. var randState uint32 var randStateMu sync.Mutex func reseed() uint32 { return uint32(time.Now().UnixNano() + int64(os.Getpid())) } func nextRandom(x uintptr) { randStateMu.Lock() r := randState if r == 0 { r = reseed() } r = r*1664525 + 1013904223 // constants from Numerical Recipes randState = r randStateMu.Unlock() copy((*RawMem)(unsafe.Pointer(x))[:6:6], fmt.Sprintf("%06d", int(1e9+r%1e9)%1e6)) } func tempFile(s, x uintptr, flags int32) (fd int, err error) { const maxTry = 10000 nconflict := 0 flags |= int32(os.O_RDWR | os.O_CREATE | os.O_EXCL | unix.O_LARGEFILE) for i := 0; i < maxTry; i++ { nextRandom(x) fdcwd := fcntl.AT_FDCWD n, _, err := unix.Syscall6(unix.SYS_OPENAT, uintptr(fdcwd), s, uintptr(flags), 0600, 0, 0) if err == 0 { return int(n), nil } if err != errno.EEXIST { return -1, err } if nconflict++; nconflict > 10 { randStateMu.Lock() randState = reseed() nconflict = 0 randStateMu.Unlock() } } return -1, unix.Errno(errno.EEXIST) }