func Listen(path string) (*Listener, error) {
rname := ".ftrig-" + randomName()
tmpfifo := filepath.Join(path, rname)
err := syscall.Mkfifo(tmpfifo, syscall.S_IRUSR|syscall.S_IWUSR|syscall.S_IWGRP|syscall.S_IWOTH)
if err != nil {
return nil, err
}
fd, fdw, name := C.int(0), C.int(0), filepath.Join(path, rname[1:])
fd, err = C.open_read(C.CString(tmpfifo))
if fd == -1 {
goto err1
}
fdw, err = C.open_write(C.CString(tmpfifo))
if fd == -1 {
C.fd_close(fd)
goto err1
}
err = os.Rename(tmpfifo, name)
if err != nil {
C.fd_close(fdw)
C.fd_close(fd)
goto err1
}
err = syscall.SetNonblock(int(fd), false)
if err != nil {
goto err1
}
return subscribe(name, uintptr(fd), uintptr(fdw))
err1:
os.Remove(tmpfifo)
if errno, ok := err.(syscall.Errno); ok {
return nil, errno
}
return nil, fmt.Errorf("unknown error opening fifo at %q", tmpfifo)
}
func notifyNosig(path, s string) (int, error) {
files, err := ioutil.ReadDir(path)
if err != nil {
return 0, err
}
success := 0
for i := range files {
if files[i].Mode()&os.ModeNamedPipe == 0 {
continue
}
p := filepath.Join(path, files[i].Name())
fd, ferr := C.open_write(C.CString(p))
if fd == -1 {
if errno, ok := ferr.(syscall.Errno); ok && errno == syscall.ENXIO {
err = errno
os.Remove(p)
}
} else {
r, ferr := C.fd_write(fd, C.CString(s), C.uint(len(s)))
if (r < 0) || uint(r) < uint(len(s)) {
if errno, ok := ferr.(syscall.Errno); ok && errno == syscall.EPIPE {
err = errno
os.Remove(p)
}
// what to do if EGAIN ? full fifo -> fix the reader !
// There's a race condition in extreme cases though ;
// but it's still better to be nonblocking - the writer
// shouldn't get in trouble because of a bad reader.
C.fd_close(fd)
} else {
C.fd_close(fd)
success++
}
}
}
return success, err
}
func Clean(path string) error {
files, err := ioutil.ReadDir(path)
if err != nil {
return nil // yes, we don't care if the dir failed to scan
}
for i := range files {
if files[i].Mode()&os.ModeNamedPipe == 0 {
continue
}
p := filepath.Join(path, files[i].Name())
fd, ferr := C.open_write(C.CString(p))
if fd >= 0 {
C.fd_close(fd)
} else if errno, ok := ferr.(syscall.Errno); ok && errno == syscall.ENXIO {
err = os.Remove(p)
}
}
return err
}
func (x *Listener) close() {
os.Remove(x.path)
C.fd_close(C.int(x.fdw))
x.f.Close()
}