Re-design of the original gocryptfs code to work as a library.
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package syscallcompat
import (
"syscall"
"golang.org/x/sys/unix"
)
// retryEINTR executes operation `op` and retries if it gets EINTR.
//
// Like ignoringEINTR() in the Go stdlib:
// https://github.com/golang/go/blob/d2a80f3fb5b44450e0b304ac5a718f99c053d82a/src/os/file_posix.go#L243
//
// This is needed because CIFS throws lots of EINTR errors:
// https://github.com/rfjakob/gocryptfs/issues/483
//
// Don't use retryEINTR() with syscall.Close()!
// See https://code.google.com/p/chromium/issues/detail?id=269623 .
func retryEINTR(op func() error) error {
for {
err := op()
if err != syscall.EINTR {
return err
}
}
}
// retryEINTR2 is like retryEINTR but for functions that return an (int, error)
// pair like syscall.Create().
func retryEINTR2(op func() (int, error)) (int, error) {
for {
ret, err := op()
if err != syscall.EINTR {
return ret, err
}
}
}
// Open wraps syscall.Open.
// Retries on EINTR.
func Open(path string, mode int, perm uint32) (fd int, err error) {
fd, err = retryEINTR2(func() (int, error) {
return syscall.Open(path, mode, perm)
})
return fd, err
}
// Renameat wraps the Renameat syscall.
// Retries on EINTR.
func Renameat(olddirfd int, oldpath string, newdirfd int, newpath string) (err error) {
err = retryEINTR(func() error {
return unix.Renameat(olddirfd, oldpath, newdirfd, newpath)
})
return err
}
// Unlinkat syscall.
// Retries on EINTR.
func Unlinkat(dirfd int, path string, flags int) (err error) {
err = retryEINTR(func() error {
return unix.Unlinkat(dirfd, path, flags)
})
return err
}
// Flush is a helper for the FUSE command FLUSH.
// Retries on EINTR.
func Flush(fd int) error {
for {
// Flushing is achieved by closing a dup'd fd.
newFd, err := syscall.Dup(fd)
if err == syscall.EINTR {
continue
}
if err != nil {
return err
}
err = syscall.Close(newFd)
// Even if we get EINTR here, newFd is dead - see
// https://code.google.com/p/chromium/issues/detail?id=269623 .
// We have to make a new one with Dup(), so continue at the top.
if err == syscall.EINTR {
continue
}
return err
}
}