fixes #383 Would like peerid for IPC

We offer uid, gid, process id, and even zone id where we have them.
Docs and tests are provided.

7 files changed, 293 insertions, 3 deletions

diff --git a/src/core/platform.h b/src/core/platform.h
index 671556d8..6e7acdbf 100644
--- a/src/core/platform.h
+++ b/src/core/platform.h
@@ -341,6 +341,21 @@ extern void nni_plat_ipc_pipe_send(nni_plat_ipc_pipe *, nni_aio *);
 // The platform may modify the iovs.
 extern void nni_plat_ipc_pipe_recv(nni_plat_ipc_pipe *, nni_aio *);
 
+// nni_plat_ipc_pipe_get_peer_uid obtains the peer user id, if possible.
+// NB: Only POSIX systems support user IDs.
+extern int nni_plat_ipc_pipe_get_peer_uid(nni_plat_ipc_pipe *, uint64_t *);
+
+// nni_plat_ipc_pipe_get_peer_gid obtains the peer group id, if possible.
+// NB: Only POSIX systems support group IDs.
+extern int nni_plat_ipc_pipe_get_peer_gid(nni_plat_ipc_pipe *, uint64_t *);
+
+// nni_plat_ipc_pipe_get_peer_pid obtains the peer process id, if possible.
+extern int nni_plat_ipc_pipe_get_peer_pid(nni_plat_ipc_pipe *, uint64_t *);
+
+// nni_plat_ipc_pipe_get_peer_zoneid obtains the peer zone id, if possible.
+// NB: Only illumos & SunOS systems have the notion of "zones".
+extern int nni_plat_ipc_pipe_get_peer_zoneid(nni_plat_ipc_pipe *, uint64_t *);
+
 //
 // UDP support. UDP is not connection oriented, and only has the notion
 // of being bound, sendto, and recvfrom.  (It is possible to set up a
diff --git a/src/platform/posix/posix_aio.h b/src/platform/posix/posix_aio.h
index 3954f225..7d6a7231 100644
--- a/src/platform/posix/posix_aio.h
+++ b/src/platform/posix/posix_aio.h
@@ -33,6 +33,8 @@ extern int  nni_posix_pipedesc_peername(nni_posix_pipedesc *, nni_sockaddr *);
 extern int  nni_posix_pipedesc_sockname(nni_posix_pipedesc *, nni_sockaddr *);
 extern int  nni_posix_pipedesc_set_nodelay(nni_posix_pipedesc *, bool);
 extern int  nni_posix_pipedesc_set_keepalive(nni_posix_pipedesc *, bool);
+extern int  nni_posix_pipedesc_get_peerid(
+     nni_posix_pipedesc *, uint64_t *, uint64_t *, uint64_t *, uint64_t *);
 
 extern int  nni_posix_epdesc_init(nni_posix_epdesc **, int);
 extern void nni_posix_epdesc_set_local(nni_posix_epdesc *, void *, size_t);
diff --git a/src/platform/posix/posix_ipc.c b/src/platform/posix/posix_ipc.c
index c1bb9292..5ba3c8fb 100644
--- a/src/platform/posix/posix_ipc.c
+++ b/src/platform/posix/posix_ipc.c
@@ -183,4 +183,68 @@ nni_plat_ipc_pipe_recv(nni_plat_ipc_pipe *p, nni_aio *aio)
 	nni_posix_pipedesc_recv((void *) p, aio);
 }
 
+int
+nni_plat_ipc_pipe_get_peer_uid(nni_plat_ipc_pipe *p, uint64_t *uid)
+{
+	int      rv;
+	uint64_t ignore;
+
+	if ((rv = nni_posix_pipedesc_get_peerid(
+	         (void *) p, uid, &ignore, &ignore, &ignore)) != 0) {
+		return (rv);
+	}
+	return (0);
+}
+
+int
+nni_plat_ipc_pipe_get_peer_gid(nni_plat_ipc_pipe *p, uint64_t *gid)
+{
+	int      rv;
+	uint64_t ignore;
+
+	if ((rv = nni_posix_pipedesc_get_peerid(
+	         (void *) p, &ignore, gid, &ignore, &ignore)) != 0) {
+		return (rv);
+	}
+	return (0);
+}
+
+int
+nni_plat_ipc_pipe_get_peer_zoneid(nni_plat_ipc_pipe *p, uint64_t *zid)
+{
+	int      rv;
+	uint64_t ignore;
+	uint64_t id;
+
+	if ((rv = nni_posix_pipedesc_get_peerid(
+	         (void *) p, &ignore, &ignore, &ignore, &id)) != 0) {
+		return (rv);
+	}
+	if (id == (uint64_t) -1) {
+		// NB: -1 is not a legal zone id (illumos/Solaris)
+		return (NNG_ENOTSUP);
+	}
+	*zid = id;
+	return (0);
+}
+
+int
+nni_plat_ipc_pipe_get_peer_pid(nni_plat_ipc_pipe *p, uint64_t *pid)
+{
+	int      rv;
+	uint64_t ignore;
+	uint64_t id;
+
+	if ((rv = nni_posix_pipedesc_get_peerid(
+	         (void *) p, &ignore, &ignore, &id, &ignore)) != 0) {
+		return (rv);
+	}
+	if (id == (uint64_t) -1) {
+		// NB: -1 is not a legal process id
+		return (NNG_ENOTSUP);
+	}
+	*pid = id;
+	return (0);
+}
+
 #endif // NNG_PLATFORM_POSIX
diff --git a/src/platform/posix/posix_pipedesc.c b/src/platform/posix/posix_pipedesc.c
index f9cbb94b..61005ca8 100644
--- a/src/platform/posix/posix_pipedesc.c
+++ b/src/platform/posix/posix_pipedesc.c
@@ -26,6 +26,12 @@
 #include <sys/types.h>
 #include <sys/uio.h>
 #include <unistd.h>
+#if defined(NNG_HAVE_GETPEERUCRED)
+#include <ucred.h>
+#elif defined(NNG_HAVE_LOCALPEERCRED)
+#include <sys/ucred.h>
+#include <sys/un.h>
+#endif
 
 // nni_posix_pipedesc is a descriptor kept one per transport pipe (i.e. open
 // file descriptor for TCP socket, etc.)  This contains the list of pending
@@ -402,6 +408,68 @@ nni_posix_pipedesc_init(nni_posix_pipedesc **pdp, int fd)
 	return (0);
 }
 
+int
+nni_posix_pipedesc_get_peerid(nni_posix_pipedesc *pd, uint64_t *euid,
+    uint64_t *egid, uint64_t *prid, uint64_t *znid)
+{
+	int fd = pd->node.fd;
+#if defined(NNG_HAVE_GETPEEREID)
+	uid_t uid;
+	gid_t gid;
+
+	if (getpeereid(fd, &uid, &gid) != 0) {
+		return (nni_plat_errno(errno));
+	}
+	*euid = uid;
+	*egid = gid;
+	*prid = (uint64_t) -1;
+	*znid = (uint64_t) -1;
+	return (0);
+#elif defined(NNG_HAVE_GETPEERUCRED)
+	ucred *ucp;
+	if (getpeerucred(fd, &ucp) != 0) {
+		return (nni_plat_errno(errno));
+	}
+	*euid = ucred_geteuid(ucp);
+	*egid = ucred_geteuid(ucp);
+	*prid = ucred_getpid(ucp);
+	*znid = ucred_getzoneid(ucp);
+	ucred_free(ucp);
+	return (0);
+#elif defined(NNG_HAVE_SOPEERCRED)
+	struct ucred uc;
+	socklen_t    len = sizeof(uc);
+	if (getsockopt(fd, SOL_SOCKET, SO_PEERCRED, &uc, &len) != 0) {
+		return (nni_plat_errno(errno));
+	}
+	*euid = uc.uid;
+	*egid = uc.gid;
+	*prid = uc.pid;
+	*znid = (uint64_t) -1;
+	return (0);
+#elif defined(NNG_HAVE_LOCALPEERCRED)
+	struct xucred xu;
+	socklen_t     len = sizeof(xu);
+	if (getsockopt(fd, SOL_LOCAL, LOCAL_PEERCRED, &xu, &len) != 0) {
+		return (nni_plat_errno(errno));
+	}
+	*euid = xu.cr_uid;
+	*egid = xu.cr_gid;
+	*prid = (uint64_t) -1; // XXX: macOS has undocumented LOCAL_PEERPID...
+	*znid = (uint64_t) -1;
+	return (0);
+#else
+	if (fd < 0) {
+		return (NNG_ECLOSED);
+	}
+	NNI_ARG_UNUSED(euid);
+	NNI_ARG_UNUSED(egid);
+	NNI_ARG_UNUSED(prid);
+	NNI_ARG_UNUSED(znid);
+	return (NNG_ENOTSUP);
+#endif
+}
+
 void
 nni_posix_pipedesc_fini(nni_posix_pipedesc *pd)
 {
diff --git a/src/platform/windows/win_ipc.c b/src/platform/windows/win_ipc.c
index 7d118672..c6376cc7 100644
--- a/src/platform/windows/win_ipc.c
+++ b/src/platform/windows/win_ipc.c
@@ -16,6 +16,7 @@
 
 struct nni_plat_ipc_pipe {
 	HANDLE        p;
+	int           mode;
 	nni_win_event rcv_ev;
 	nni_win_event snd_ev;
 };
@@ -128,7 +129,7 @@ nni_win_ipc_pipe_finish(nni_win_event *evt, nni_aio *aio)
 }
 
 static int
-nni_win_ipc_pipe_init(nni_plat_ipc_pipe **pipep, HANDLE p)
+nni_win_ipc_pipe_init(nni_plat_ipc_pipe **pipep, HANDLE p, int mode)
 {
 	nni_plat_ipc_pipe *pipe;
 	int                rv;
@@ -136,6 +137,7 @@ nni_win_ipc_pipe_init(nni_plat_ipc_pipe **pipep, HANDLE p)
 	if ((pipe = NNI_ALLOC_STRUCT(pipe)) == NULL) {
 		return (NNG_ENOMEM);
 	}
+	pipe->mode = mode;
 	rv = nni_win_event_init(&pipe->rcv_ev, &nni_win_ipc_pipe_ops, pipe);
 	if (rv != 0) {
 		nni_plat_ipc_pipe_fini(pipe);
@@ -189,6 +191,56 @@ nni_plat_ipc_pipe_fini(nni_plat_ipc_pipe *pipe)
 }
 
 int
+nni_plat_ipc_pipe_get_peer_uid(nni_plat_ipc_pipe *pipe, uint64_t *id)
+{
+	NNI_ARG_UNUSED(pipe);
+	NNI_ARG_UNUSED(id);
+	return (NNG_ENOTSUP);
+}
+
+int
+nni_plat_ipc_pipe_get_peer_gid(nni_plat_ipc_pipe *pipe, uint64_t *id)
+{
+	NNI_ARG_UNUSED(pipe);
+	NNI_ARG_UNUSED(id);
+	return (NNG_ENOTSUP);
+}
+
+int
+nni_plat_ipc_pipe_get_peer_zoneid(nni_plat_ipc_pipe *pipe, uint64_t *id)
+{
+	NNI_ARG_UNUSED(pipe);
+	NNI_ARG_UNUSED(id);
+	return (NNG_ENOTSUP);
+}
+
+// nni_plat_ipc_pipe_get_peer_gid obtains the peer group id, if possible.
+// NB: Only POSIX systems support group IDs.
+int
+nni_plat_ipc_pipe_get_peer_pid(nni_plat_ipc_pipe *pipe, uint64_t *pid)
+{
+	ULONG id;
+	switch (pipe->mode) {
+	case NNI_EP_MODE_DIAL:
+		if (!GetNamedPipeServerProcessId(pipe->p, &id)) {
+			return (nni_win_error(GetLastError()));
+		}
+		*pid = id;
+		break;
+	case NNI_EP_MODE_LISTEN:
+		if (!GetNamedPipeClientProcessId(pipe->p, &id)) {
+			return (nni_win_error(GetLastError()));
+		}
+		*pid = id;
+		break;
+	default:
+		// Should never occur!
+		return (NNG_EINVAL);
+	}
+	return (0);
+}
+
+int
 nni_plat_ipc_ep_init(nni_plat_ipc_ep **epp, const nni_sockaddr *sa, int mode)
 {
 	const char *     path;
@@ -331,7 +383,8 @@ nni_win_ipc_acc_finish(nni_win_event *evt, nni_aio *aio)
 	oldp  = ep->p;
 	ep->p = newp;
 
-	if ((rv = nni_win_ipc_pipe_init(&pipe, oldp)) != 0) {
+	if ((rv = nni_win_ipc_pipe_init(&pipe, oldp, NNI_EP_MODE_LISTEN)) !=
+	    0) {
 		// The new pipe is already fine for us.  Discard
 		// the old one, since failed to be able to use it.
 		DisconnectNamedPipe(oldp);
@@ -466,7 +519,8 @@ nni_win_ipc_conn_thr(void *arg)
 				}
 				goto fail;
 			}
-			if (((rv = nni_win_ipc_pipe_init(&pipe, p)) != 0) ||
+			if (((rv = nni_win_ipc_pipe_init(
+			          &pipe, p, NNI_EP_MODE_DIAL)) != 0) ||
 			    ((rv = nni_win_iocp_register(p)) != 0)) {
 				goto fail;
 			}
diff --git a/src/transport/ipc/ipc.c b/src/transport/ipc/ipc.c
index 3dbccb50..e5f3d533 100644
--- a/src/transport/ipc/ipc.c
+++ b/src/transport/ipc/ipc.c
@@ -537,6 +537,54 @@ nni_ipc_pipe_get_addr(void *arg, void *buf, size_t *szp, int typ)
 	return (nni_copyout_sockaddr(&p->sa, buf, szp, typ));
 }
 
+static int
+nni_ipc_pipe_get_peer_uid(void *arg, void *buf, size_t *szp, int typ)
+{
+	nni_ipc_pipe *p = arg;
+	uint64_t      id;
+	int           rv;
+	if ((rv = nni_plat_ipc_pipe_get_peer_uid(p->ipp, &id)) != 0) {
+		return (rv);
+	}
+	return (nni_copyout_u64(id, buf, szp, typ));
+}
+
+static int
+nni_ipc_pipe_get_peer_gid(void *arg, void *buf, size_t *szp, int typ)
+{
+	nni_ipc_pipe *p = arg;
+	uint64_t      id;
+	int           rv;
+	if ((rv = nni_plat_ipc_pipe_get_peer_gid(p->ipp, &id)) != 0) {
+		return (rv);
+	}
+	return (nni_copyout_u64(id, buf, szp, typ));
+}
+
+static int
+nni_ipc_pipe_get_peer_pid(void *arg, void *buf, size_t *szp, int typ)
+{
+	nni_ipc_pipe *p = arg;
+	uint64_t      id;
+	int           rv;
+	if ((rv = nni_plat_ipc_pipe_get_peer_pid(p->ipp, &id)) != 0) {
+		return (rv);
+	}
+	return (nni_copyout_u64(id, buf, szp, typ));
+}
+
+static int
+nni_ipc_pipe_get_peer_zoneid(void *arg, void *buf, size_t *szp, int typ)
+{
+	nni_ipc_pipe *p = arg;
+	uint64_t      id;
+	int           rv;
+	if ((rv = nni_plat_ipc_pipe_get_peer_zoneid(p->ipp, &id)) != 0) {
+		return (rv);
+	}
+	return (nni_copyout_u64(id, buf, szp, typ));
+}
+
 static void
 nni_ipc_ep_fini(void *arg)
 {
@@ -785,6 +833,26 @@ static nni_tran_pipe_option nni_ipc_pipe_options[] = {
 	    .po_type   = NNI_TYPE_SOCKADDR,
 	    .po_getopt = nni_ipc_pipe_get_addr,
 	},
+	{
+	    .po_name   = NNG_OPT_IPC_PEER_UID,
+	    .po_type   = NNI_TYPE_UINT64,
+	    .po_getopt = nni_ipc_pipe_get_peer_uid,
+	},
+	{
+	    .po_name   = NNG_OPT_IPC_PEER_GID,
+	    .po_type   = NNI_TYPE_UINT64,
+	    .po_getopt = nni_ipc_pipe_get_peer_gid,
+	},
+	{
+	    .po_name   = NNG_OPT_IPC_PEER_PID,
+	    .po_type   = NNI_TYPE_UINT64,
+	    .po_getopt = nni_ipc_pipe_get_peer_pid,
+	},
+	{
+	    .po_name   = NNG_OPT_IPC_PEER_ZONEID,
+	    .po_type   = NNI_TYPE_UINT64,
+	    .po_getopt = nni_ipc_pipe_get_peer_zoneid,
+	},
 	// terminate list
 	{
 	    .po_name = NULL,
diff --git a/src/transport/ipc/ipc.h b/src/transport/ipc/ipc.h
index 42cbdb08..497fb2b5 100644
--- a/src/transport/ipc/ipc.h
+++ b/src/transport/ipc/ipc.h
@@ -28,4 +28,23 @@ NNG_DECL int nng_ipc_register(void);
 // this for security.
 #define NNG_OPT_IPC_PERMISSIONS "ipc:permissions"
 
+// Peer UID.  This is only available on POSIX style systems.
+#define NNG_OPT_IPC_PEER_UID "ipc:peer-uid"
+
+// Peer GID (primary group).  This is only available on POSIX style systems.
+#define NNG_OPT_IPC_PEER_GID "ipc:peer-gid"
+
+// Peer process ID.  Available on Windows, Linux, and SunOS.
+// In theory we could obtain this with the first message sent,
+// but we have elected not to do this for now. (Nice RFE for a FreeBSD
+// guru though.)
+#define NNG_OPT_IPC_PEER_PID "ipc:peer-pid"
+
+// Peer Zone ID.  Only on SunOS systems.  (Linux containers have no
+// definable kernel identity; they are a user-land fabrication made up
+// from various pieces of different namespaces. FreeBSD does have
+// something called JailIDs, but it isn't obvious how to determine this,
+// or even if processes can use IPC across jail boundaries.)
+#define NNG_OPT_IPC_PEER_ZONEID "ipc:peer-zoneid"
+
 #endif // NNG_TRANSPORT_IPC_IPC_H