diff --git a/internal/lib/os/wait_waitid.go b/internal/lib/os/wait_waitid.go
index c14aba38..0c89c81b 100644
--- a/internal/lib/os/wait_waitid.go
+++ b/internal/lib/os/wait_waitid.go
@@ -21,7 +21,7 @@ const _P_PID = 1
 // int waitid(idtype_t idtype, id_t id, siginfo_t *infop, int options);
 //
 //go:linkname waitid C.waitid
-func waitid(idtype, id uintptr, infop *[16]uint64, options c.Int) c.Int
+func waitid(idtype, id uintptr, infop *uint64, options c.Int) c.Int
 
 // blockUntilWaitable attempts to block until a call to p.Wait will
 // succeed immediately, and reports whether it has done so.
@@ -35,7 +35,7 @@ func (p *Process) blockUntilWaitable() (bool, error) {
 	psig := &siginfo[0]
 	var e syscall.Errno
 	for {
-		e = syscall.Errno(waitid(_P_PID, uintptr(p.Pid), psig, syscall.WEXITED|syscall.WNOWAIT, 0, 0))
+		e = syscall.Errno(waitid(_P_PID, uintptr(p.Pid), psig, syscall.WEXITED|syscall.WNOWAIT))
 		if e != syscall.EINTR {
 			break
 		}
diff --git a/internal/lib/syscall/forkpipe2.go b/internal/lib/syscall/forkpipe2.go
index 9a93b258..b5cd1d30 100644
--- a/internal/lib/syscall/forkpipe2.go
+++ b/internal/lib/syscall/forkpipe2.go
@@ -6,12 +6,16 @@
 
 package syscall
 
-import "sync"
+import (
+	"sync"
+
+	"github.com/goplus/llgo/c/syscall"
+)
 
 // forkExecPipe atomically opens a pipe with O_CLOEXEC set on both file
 // descriptors.
 func forkExecPipe(p []int) error {
-	return Pipe2(p, O_CLOEXEC)
+	return Pipe2(p, syscall.O_CLOEXEC)
 }
 
 var (
diff --git a/internal/lib/syscall/syscall_linux.go b/internal/lib/syscall/syscall_linux.go
index cad706d3..3b643db2 100644
--- a/internal/lib/syscall/syscall_linux.go
+++ b/internal/lib/syscall/syscall_linux.go
@@ -11,6 +11,14 @@
 
 package syscall
 
+import (
+	_ "unsafe"
+
+	"github.com/goplus/llgo/c"
+)
+
+// -----------------------------------------------------------------------------
+
 type WaitStatus uint32
 
 // Wait status is 7 bits at bottom, either 0 (exited),
@@ -70,6 +78,35 @@ func (w WaitStatus) TrapCause() int {
 }
 */
 
+// -----------------------------------------------------------------------------
+
+// int pipe2(int pipefd[2], int flags);
+//
+//go:linkname pipe2 C.pipe2
+func pipe2(pipefd *[2]c.Int, flags c.Int) c.Int
+
+func Pipe(p []int) error {
+	return Pipe2(p, 0)
+}
+
+func Pipe2(p []int, flags int) error {
+	if len(p) != 2 {
+		return EINVAL
+	}
+	var pp [2]c.Int
+	ret := pipe2(&pp, c.Int(flags))
+	if ret == 0 {
+		p[0] = int(pp[0])
+		p[1] = int(pp[1])
+		return nil
+	}
+	return Errno(ret)
+}
+
+// -----------------------------------------------------------------------------
+
 func Faccessat(dirfd int, path string, mode uint32, flags int) (err error) {
 	panic("todo: syscall.Faccessat")
 }
+
+// -----------------------------------------------------------------------------