Index: head/sys/compat/cloudabi/cloudabi_sock.c
===================================================================
--- head/sys/compat/cloudabi/cloudabi_sock.c
+++ head/sys/compat/cloudabi/cloudabi_sock.c
@@ -27,14 +27,62 @@
 __FBSDID("$FreeBSD$");
 
 #include <sys/param.h>
+#include <sys/capsicum.h>
+#include <sys/lock.h>
+#include <sys/malloc.h>
+#include <sys/mutex.h>
+#include <sys/protosw.h>
 #include <sys/socket.h>
+#include <sys/socketvar.h>
 #include <sys/syscallsubr.h>
 #include <sys/sysproto.h>
 #include <sys/systm.h>
 #include <sys/un.h>
 
+#include <net/vnet.h>
+
+#include <netinet/in.h>
+
 #include <compat/cloudabi/cloudabi_proto.h>
 #include <compat/cloudabi/cloudabi_syscalldefs.h>
+#include <compat/cloudabi/cloudabi_util.h>
+
+/* Converts FreeBSD's struct sockaddr to CloudABI's cloudabi_sockaddr_t. */
+void
+cloudabi_convert_sockaddr(const struct sockaddr *sa, socklen_t sal,
+    cloudabi_sockaddr_t *rsa)
+{
+	const struct sockaddr_in *sin;
+	const struct sockaddr_in6 *sin6;
+
+	/* Zero-sized socket address. */
+	if (sal < offsetof(struct sockaddr, sa_family) + sizeof(sa->sa_family))
+		return;
+
+	switch (sa->sa_family) {
+	case AF_INET:
+		if (sal < sizeof(struct sockaddr_in))
+			return;
+		sin = (const struct sockaddr_in *)sa;
+		rsa->sa_family = CLOUDABI_AF_INET;
+		memcpy(&rsa->sa_inet.addr, &sin->sin_addr,
+		    sizeof(rsa->sa_inet.addr));
+		rsa->sa_inet.port = ntohs(sin->sin_port);
+		return;
+	case AF_INET6:
+		if (sal < sizeof(struct sockaddr_in6))
+			return;
+		sin6 = (const struct sockaddr_in6 *)sa;
+		rsa->sa_family = CLOUDABI_AF_INET6;
+		memcpy(&rsa->sa_inet6.addr, &sin6->sin6_addr,
+		    sizeof(rsa->sa_inet6.addr));
+		rsa->sa_inet6.port = ntohs(sin6->sin6_port);
+		return;
+	case AF_UNIX:
+		rsa->sa_family = CLOUDABI_AF_UNIX;
+		return;
+	}
+}
 
 /* Copies a pathname into a UNIX socket address structure. */
 static int
@@ -62,9 +110,27 @@
 cloudabi_sys_sock_accept(struct thread *td,
     struct cloudabi_sys_sock_accept_args *uap)
 {
+	struct sockaddr *sa;
+	cloudabi_sockstat_t ss = {};
+	socklen_t sal;
+	int error;
 
-	/* Not implemented. */
-	return (ENOSYS);
+	if (uap->buf == NULL) {
+		/* Only return the new file descriptor number. */
+		return (kern_accept(td, uap->s, NULL, NULL, NULL));
+	} else {
+		/* Also return properties of the new socket descriptor. */
+		sal = MAX(sizeof(struct sockaddr_in),
+		    sizeof(struct sockaddr_in6));
+		error = kern_accept(td, uap->s, (void *)&sa, &sal, NULL);
+		if (error != 0)
+			return (error);
+
+		/* TODO(ed): Fill the other members of cloudabi_sockstat_t. */
+		cloudabi_convert_sockaddr(sa, sal, &ss.ss_peername);
+		free(sa, M_SONAME);
+		return (copyout(&ss, uap->buf, sizeof(ss)));
+	}
 }
 
 int
@@ -134,7 +200,51 @@
 cloudabi_sys_sock_stat_get(struct thread *td,
     struct cloudabi_sys_sock_stat_get_args *uap)
 {
+	cloudabi_sockstat_t ss = {};
+	cap_rights_t rights;
+	struct file *fp;
+	struct sockaddr *sa;
+	struct socket *so;
+	int error;
+
+	error = getsock_cap(td, uap->fd, cap_rights_init(&rights,
+	    CAP_GETSOCKOPT | CAP_GETPEERNAME | CAP_GETSOCKNAME), &fp, NULL);
+	if (error != 0)
+		return (error);
+	so = fp->f_data;
+
+	CURVNET_SET(so->so_vnet);
+
+	/* Set ss_sockname. */
+	error = so->so_proto->pr_usrreqs->pru_sockaddr(so, &sa);
+	if (error == 0) {
+		cloudabi_convert_sockaddr(sa, sa->sa_len, &ss.ss_sockname);
+		free(sa, M_SONAME);
+	}
+
+	/* Set ss_peername. */
+	if ((so->so_state & (SS_ISCONNECTED | SS_ISCONFIRMING)) != 0) {
+		error = so->so_proto->pr_usrreqs->pru_peeraddr(so, &sa);
+		if (error == 0) {
+			cloudabi_convert_sockaddr(sa, sa->sa_len,
+			    &ss.ss_peername);
+			free(sa, M_SONAME);
+		}
+	}
+
+	CURVNET_RESTORE();
+
+	/* Set ss_error. */
+	SOCK_LOCK(so);
+	ss.ss_error = so->so_error;
+	if ((uap->flags & CLOUDABI_SOCKSTAT_CLEAR_ERROR) != 0)
+		so->so_error = 0;
+	SOCK_UNLOCK(so);
+
+	/* Set ss_state. */
+	if ((so->so_options & SO_ACCEPTCONN) != 0)
+		ss.ss_state |= CLOUDABI_SOCKSTAT_ACCEPTCONN;
 
-	/* Not implemented. */
-	return (ENOSYS);
+	fdrop(fp, td);
+	return (copyout(&ss, uap->buf, sizeof(ss)));
 }
Index: head/sys/compat/cloudabi/cloudabi_util.h
===================================================================
--- head/sys/compat/cloudabi/cloudabi_util.h
+++ head/sys/compat/cloudabi/cloudabi_util.h
@@ -28,6 +28,8 @@
 #ifndef _CLOUDABI_UTIL_H_
 #define	_CLOUDABI_UTIL_H_
 
+#include <sys/socket.h>
+
 #include <compat/cloudabi/cloudabi_syscalldefs.h>
 
 struct file;
@@ -41,6 +43,10 @@
 /* Converts a FreeBSD errno to a CloudABI errno. */
 cloudabi_errno_t cloudabi_convert_errno(int);
 
+/* Converts FreeBSD's struct sockaddr to CloudABI's cloudabi_sockaddr_t. */
+void cloudabi_convert_sockaddr(const struct sockaddr *, socklen_t,
+    cloudabi_sockaddr_t *);
+
 /* Converts a file descriptor to a CloudABI file descriptor type. */
 cloudabi_filetype_t cloudabi_convert_filetype(const struct file *);