//go:build dragonfly || freebsd || linux || netbsd || openbsd || solaris

package syscall

import "sync"

// forkExecPipe atomically opens a pipe with O_CLOEXEC set on both file
// descriptors.
func forkExecPipe(p []int) error {
	return Pipe2(p, O_CLOEXEC)
}

var (
	// Guard the forking variable.
	forkingLock sync.Mutex
	// Number of goroutines currently forking, and thus the

// inherit are not the ones that can take an arbitrarily long time
// to create: pipe returns instantly, and the net package uses
// non-blocking I/O to accept on a listening socket.
// The rules for which file descriptor-creating operations use the
// ForkLock are as follows:
//
//   - [Pipe]. Use pipe2 if available. Otherwise, does not block,
//     so use ForkLock.

}

//sysnb	pipe() (r int, w int, err error)

func Pipe(p []int) (err error) {
	if len(p) != 2 {
		return EINVAL
	}
	r, w, err := pipe()
	if err == nil {
		p[0], p[1] = r, w
	}
	return
}

//sysnb	pipe2(p *[2]_C_int, flags int) (r int, w int, err error)

func Pipe2(p []int, flags int) (err error) {
	if len(p) != 2 {
		return EINVAL
	}

	// (We expect a write to a closed pipe can fail, but a concurrent fork of a
	// child process can cause the pipe to unexpectedly remain open.)

	limit := 1
	if !read {
		// Get the amount we have to write to overload a pipe
		// with no reader.
		limit = 131073
		if b, err := os.ReadFile("/proc/sys/fs/pipe-max-size"); err == nil {

# exec".
# Important: "tfrun foo | bar" is "( tfrun foo ) | bar", not "tfrun (foo | bar)".
# Therefore, "tfrun" commands cannot include pipes -- which is
# probably for the better. If a pipe is necessary for something, it is probably
# complex. Write a well-documented script under utilities/ to encapsulate the
# functionality instead.
tfrun() { "$@"; }

	return readInt(buf, unsafe.Offsetof(Dirent{}.Namlen), unsafe.Sizeof(Dirent{}.Namlen))
}

func Pipe(p []int) (err error) {
	return Pipe2(p, 0)
}

//sysnb pipe2(p *[2]_C_int, flags int) (err error)

func Pipe2(p []int, flags int) error {
	if len(p) != 2 {
		return EINVAL
	}
	var pp [2]_C_int
	err := pipe2(&pp, flags)
	if err == nil {
		p[0] = int(pp[0])
		p[1] = int(pp[1])
	}
	return err
}

	return readInt(buf, unsafe.Offsetof(Dirent{}.Namlen), unsafe.Sizeof(Dirent{}.Namlen))
}

func Pipe(p []int) error {
	return Pipe2(p, 0)
}

//sysnb pipe2(p *[2]_C_int, flags int) (err error)

func Pipe2(p []int, flags int) error {
	if len(p) != 2 {
		return EINVAL
	}
	var pp [2]_C_int
	err := pipe2(&pp, flags)
	if err == nil {
		p[0] = int(pp[0])
		p[1] = int(pp[1])
	}
	return err
}

        stat.length == 0
        assertSameAccessType(stat, VIA_SYMLINK)
    }

    @Requires(UnitTestPreconditions.UnixDerivative)
    def "stats named pipes"() {
        def pipe = tmpDir.file("testPipe").createNamedPipe()

        when:
        accessor.stat(pipe)
        then:
        thrown(UncheckedIOException)
    }

    @Requires(UnitTestPreconditions.FilePermissions)

	}
}

// Test that sendfile doesn't put a pipe into blocking mode.
func TestSendfilePipe(t *testing.T) {
	switch runtime.GOOS {
	case "plan9", "windows", "js", "wasip1":
		// These systems don't support deadlines on pipes.
		t.Skipf("skipping on %s", runtime.GOOS)
	}

	t.Parallel()

	ln := newLocalListener(t, "tcp")
	defer ln.Close()

	r, w, err := os.Pipe()
	if err != nil {
		t.Fatal(err)
	}

	return readInt(buf, unsafe.Offsetof(Dirent{}.Namlen), unsafe.Sizeof(Dirent{}.Namlen))
}

func Pipe(p []int) error {
	return Pipe2(p, 0)
}

//sysnb pipe2(p *[2]_C_int, flags int) (err error)

func Pipe2(p []int, flags int) error {
	if len(p) != 2 {
		return EINVAL
	}
	var pp [2]_C_int
	err := pipe2(&pp, flags)
	if err == nil {
		p[0] = int(pp[0])
		p[1] = int(pp[1])
	}
	return err
}