Add pipe2() system call.

The pipe2() function is similar to pipe() but allows setting FD_CLOEXEC and
O_NONBLOCK (on both sides) as part of the function.

If p points to two writable ints, pipe2(p, 0) is equivalent to pipe(p).

If the pointer is not valid, behaviour differs: pipe2() writes into the
array from the kernel like socketpair() does, while pipe() writes into the
array from an architecture-specific assembler wrapper.

Reviewed by:	kan, kib

3 files changed, 20 insertions, 0 deletions

diff --git a/sys/kern/capabilities.conf b/sys/kern/capabilities.conf
index 0b64503..d2fa51c 100644
--- a/sys/kern/capabilities.conf
+++ b/sys/kern/capabilities.conf
@@ -490,6 +490,7 @@ pdkill
 ## Allow pipe(2).
 ##
 pipe
+pipe2
 
 ##
 ## Allow poll(2), which will be scoped by capability rights.
diff --git a/sys/kern/sys_pipe.c b/sys/kern/sys_pipe.c
index 90c3022..493fee5e 100644
--- a/sys/kern/sys_pipe.c
+++ b/sys/kern/sys_pipe.c
@@ -477,6 +477,24 @@ sys_pipe(struct thread *td, struct pipe_args *uap)
 	return (0);
 }
 
+int
+sys_pipe2(struct thread *td, struct pipe2_args *uap)
+{
+	int error, fildes[2];
+
+	if (uap->flags & ~(O_CLOEXEC | O_NONBLOCK))
+		return (EINVAL);
+	error = kern_pipe2(td, fildes, uap->flags);
+	if (error)
+		return (error);
+	error = copyout(fildes, uap->fildes, 2 * sizeof(int));
+	if (error) {
+		(void)kern_close(td, fildes[0]);
+		(void)kern_close(td, fildes[1]);
+	}
+	return (error);
+}
+
 /*
  * Allocate kva for pipe circular buffer, the space is pageable
  * This routine will 'realloc' the size of a pipe safely, if it fails
diff --git a/sys/kern/syscalls.master b/sys/kern/syscalls.master
index 922db30..8668943 100644
--- a/sys/kern/syscalls.master
+++ b/sys/kern/syscalls.master
@@ -976,5 +976,6 @@
 				    struct sockaddr * __restrict name, \
 				    __socklen_t * __restrict anamelen, \
 				    int flags); }
+542	AUE_PIPE	STD	{ int pipe2(int *fildes, int flags); }
 ; Please copy any additions and changes to the following compatability tables:
 ; sys/compat/freebsd32/syscalls.master