svc: make sure mountd can get ports from /etc/services

At RHEL, if user set port for mountd at /etc/services as
"mount 12345/tcp", mountd should be bind to 12345, but the
latest nfs-utils, mountd get a rand port, not 12345.

This patch make sure mountd be bind to the port which was set at /etc/service.

Signed-off-by Mi Jinlong <[email protected]>

---

support/include/rpcmisc.h |    1 +
support/nfs/svc_create.c  |    9 ++++-
support/nfs/svc_socket.c  |   83 +++++++++++++++++++++-----------------------
3 files changed, 48 insertions(+), 45 deletions(-)

support/include/rpcmisc.h +1 -0

index 0b06457..b806227 100644
@@ -53,6 +53,7 @@ void		rpc_init(char *name, int prog, int vers,
 void		rpc_dispatch(struct svc_req *rq, SVCXPRT *xprt,
 				struct rpc_dtable *dtable, int nvers,
 				void *argp, void *resp);
+int		getservport(u_long number, const char *proto);
 
 extern int	_rpcpmstart;
 extern int	_rpcfdtype;

support/nfs/svc_create.c +7 -2

index b3f75ed..fd09902 100644
@@ -393,7 +393,7 @@ nfs_svc_create(char *name, const rpcprog_t program, const rpcvers_t version,
 	const struct sigaction create_sigaction = {
 		.sa_handler	= SIG_IGN,
 	};
-	unsigned int visible, up;
+	unsigned int visible, up, servport;
 	struct netconfig *nconf;
 	void *handlep;
 

@@ -417,8 +417,13 @@ nfs_svc_create(char *name, const rpcprog_t program, const rpcvers_t version,
 		if (!(nconf->nc_flag & NC_VISIBLE))
 			continue;
 		visible++;
+		if (port == 0)
+			servport = getservport(program, nconf->nc_proto);
+		else
+			servport = port;
+		
 		up += svc_create_nconf(name, program, version, dispatch,
-						port, nconf);
+						servport, nconf);
 	}
 
 	if (visible == 0)

support/nfs/svc_socket.c +35 -0

index 03a5325..ec406a9 100644
@@ -35,14 +35,46 @@
 # define __close(f)		close ((f))
 #endif
 
+int getservport(u_long number, const char *proto)
+{
+	char rpcdata [1024], servdata [1024];
+	struct rpcent rpcbuf, *rpcp;
+	struct servent servbuf, *servp = NULL;
+	int ret;
+
+	ret = getrpcbynumber_r (number, &rpcbuf, rpcdata, sizeof rpcdata,
+				&rpcp);
+	if (ret == 0 && rpcp != NULL)
+	{
+		/* First try name.  */
+		ret = getservbyname_r (rpcp->r_name, proto, &servbuf, servdata,
+					sizeof servdata, &servp);
+		if ((ret != 0 || servp == NULL) && rpcp->r_aliases)
+		{
+			const char **a;
+
+			/* Then we try aliases.  */
+			for (a = (const char **) rpcp->r_aliases; *a != NULL; a++) 
+			{
+				ret = getservbyname_r (*a, proto, &servbuf, servdata,
+							sizeof servdata, &servp);
+				if (ret == 0 && servp != NULL)
+					break;
+			}
+		}
+	}
+
+	if (ret == 0 && servp != NULL)
+		return  ntohs(servp->s_port);
+
+	return 0;
+}
+

static int
svc_socket (u_long number, int type, int protocol, int reuse) {
struct sockaddr_in addr;
socklen_t len = sizeof (struct sockaddr_in);

support/nfs/svc_socket.c +5 -43

-  char rpcdata [1024], servdata [1024];
-  struct rpcent rpcbuf, *rpcp;
-  struct servent servbuf, *servp = NULL;
  int sock, ret;
  const char *proto = protocol == IPPROTO_TCP ? "tcp" : "udp";

@@ -66,48 +98,13 @@ svc_socket (u_long number, int type, int protocol, int reuse)
 
  memset (&addr, 0, sizeof (addr));
  addr.sin_family = AF_INET;
+  addr.sin_port = htons(getservport(number, proto));
 
-  ret = getrpcbynumber_r (number, &rpcbuf, rpcdata, sizeof rpcdata,
-			  &rpcp);
-  if (ret == 0 && rpcp != NULL)
+  if (bind (sock, (struct sockaddr *) &addr, len) < 0)
    {
-      /* First try name.  */
-      ret = getservbyname_r (rpcp->r_name, proto, &servbuf, servdata,
-			     sizeof servdata, &servp);
-      if ((ret != 0 || servp == NULL) && rpcp->r_aliases)
-	{
-	  const char **a;
-
-	  /* Then we try aliases.  */
-	  for (a = (const char **) rpcp->r_aliases; *a != NULL; a++) 
-	    {
-	      ret = getservbyname_r (*a, proto, &servbuf, servdata,
-				     sizeof servdata, &servp);
-	      if (ret == 0 && servp != NULL)
-		break;
-	    }
-	}
-    }
-
-  if (ret == 0 && servp != NULL)
-    {
-      addr.sin_port = servp->s_port;
-      if (bind (sock, (struct sockaddr *) &addr, len) < 0)
-	{
-	  perror (_("svc_socket: bind problem"));
-	  (void) __close (sock);
-	  sock = -1;
-	}
-    }
-  else
-    {
-	  addr.sin_port = 0;
-	  if (bind (sock, (struct sockaddr *) &addr, len) < 0)
-	    {
-	      perror (_("svc_socket: bind problem"));
-	      (void) __close (sock);
-	      sock = -1;
-	    }
+      perror (_("svc_socket: bind problem"));
+      (void) __close (sock);
+      sock = -1;
    }
 
  if (sock >= 0)

Signature · 1 line

1.7.4.1

Hi MJ-

Quoted 4 lines · Mi Jinlong

At RHEL, if user set port for mountd at /etc/services as
"mount 12345/tcp", mountd should be bind to 12345, but the
latest nfs-utils, mountd get a rand port, not 12345.

Quoted 2 lines

This patch make sure mountd be bind to the port which was set at /etc/service.

I don't think this is documented anywhere. Is there a reason it should work this way?

The typical way to set mountd's port is to use a command line option. That's the way it works for all the other RPC daemons. By default the ports are set up at random and registered with rpcbind. That's why clients use rpcbind, and not /etc/services, to find these services.

Quoted 161 lines

Signed-off-by Mi Jinlong <[email protected]>

---

support/include/rpcmisc.h |    1 +
support/nfs/svc_create.c  |    9 ++++-
support/nfs/svc_socket.c  |   83 +++++++++++++++++++++-----------------------
3 files changed, 48 insertions(+), 45 deletions(-)

support/include/rpcmisc.h +1 -0

index 0b06457..b806227 100644
@@ -53,6 +53,7 @@ void		rpc_init(char *name, int prog, int vers,
 void		rpc_dispatch(struct svc_req *rq, SVCXPRT *xprt,
 				struct rpc_dtable *dtable, int nvers,
 				void *argp, void *resp);
+int		getservport(u_long number, const char *proto);
 
 extern int	_rpcpmstart;
 extern int	_rpcfdtype;

support/nfs/svc_create.c +7 -2

index b3f75ed..fd09902 100644
@@ -393,7 +393,7 @@ nfs_svc_create(char *name, const rpcprog_t program, const rpcvers_t version,
 	const struct sigaction create_sigaction = {
 		.sa_handler	= SIG_IGN,
 	};
-	unsigned int visible, up;
+	unsigned int visible, up, servport;
 	struct netconfig *nconf;
 	void *handlep;
 

@@ -417,8 +417,13 @@ nfs_svc_create(char *name, const rpcprog_t program, const rpcvers_t version,
 		if (!(nconf->nc_flag & NC_VISIBLE))
 			continue;
 		visible++;
+		if (port == 0)
+			servport = getservport(program, nconf->nc_proto);
+		else
+			servport = port;
+		
 		up += svc_create_nconf(name, program, version, dispatch,
-						port, nconf);
+						servport, nconf);
 	}
 
 	if (visible == 0)

support/nfs/svc_socket.c +35 -0

index 03a5325..ec406a9 100644
@@ -35,14 +35,46 @@
 # define __close(f)		close ((f))
 #endif
 
+int getservport(u_long number, const char *proto)
+{
+	char rpcdata [1024], servdata [1024];
+	struct rpcent rpcbuf, *rpcp;
+	struct servent servbuf, *servp = NULL;
+	int ret;
+
+	ret = getrpcbynumber_r (number, &rpcbuf, rpcdata, sizeof rpcdata,
+				&rpcp);
+	if (ret == 0 && rpcp != NULL)
+	{
+		/* First try name.  */
+		ret = getservbyname_r (rpcp->r_name, proto, &servbuf, servdata,
+					sizeof servdata, &servp);
+		if ((ret != 0 || servp == NULL) && rpcp->r_aliases)
+		{
+			const char **a;
+
+			/* Then we try aliases.  */
+			for (a = (const char **) rpcp->r_aliases; *a != NULL; a++) 
+			{
+				ret = getservbyname_r (*a, proto, &servbuf, servdata,
+							sizeof servdata, &servp);
+				if (ret == 0 && servp != NULL)
+					break;
+			}
+		}
+	}
+
+	if (ret == 0 && servp != NULL)
+		return  ntohs(servp->s_port);
+
+	return 0;
+}
+

static int
svc_socket (u_long number, int type, int protocol, int reuse) {
struct sockaddr_in addr;
socklen_t len = sizeof (struct sockaddr_in);

support/nfs/svc_socket.c +5 -43

-  char rpcdata [1024], servdata [1024];
-  struct rpcent rpcbuf, *rpcp;
-  struct servent servbuf, *servp = NULL;
  int sock, ret;
  const char *proto = protocol == IPPROTO_TCP ? "tcp" : "udp";

@@ -66,48 +98,13 @@ svc_socket (u_long number, int type, int protocol, int reuse)
 
  memset (&addr, 0, sizeof (addr));
  addr.sin_family = AF_INET;
+  addr.sin_port = htons(getservport(number, proto));
 
-  ret = getrpcbynumber_r (number, &rpcbuf, rpcdata, sizeof rpcdata,
-			  &rpcp);
-  if (ret == 0 && rpcp != NULL)
+  if (bind (sock, (struct sockaddr *) &addr, len) < 0)
    {
-      /* First try name.  */
-      ret = getservbyname_r (rpcp->r_name, proto, &servbuf, servdata,
-			     sizeof servdata, &servp);
-      if ((ret != 0 || servp == NULL) && rpcp->r_aliases)
-	{
-	  const char **a;
-
-	  /* Then we try aliases.  */
-	  for (a = (const char **) rpcp->r_aliases; *a != NULL; a++) 
-	    {
-	      ret = getservbyname_r (*a, proto, &servbuf, servdata,
-				     sizeof servdata, &servp);
-	      if (ret == 0 && servp != NULL)
-		break;
-	    }
-	}
-    }
-
-  if (ret == 0 && servp != NULL)
-    {
-      addr.sin_port = servp->s_port;
-      if (bind (sock, (struct sockaddr *) &addr, len) < 0)
-	{
-	  perror (_("svc_socket: bind problem"));
-	  (void) __close (sock);
-	  sock = -1;
-	}
-    }
-  else
-    {
-	  addr.sin_port = 0;
-	  if (bind (sock, (struct sockaddr *) &addr, len) < 0)
-	    {
-	      perror (_("svc_socket: bind problem"));
-	      (void) __close (sock);
-	      sock = -1;
-	    }
+      perror (_("svc_socket: bind problem"));
+      (void) __close (sock);
+      sock = -1;
    }
 
  if (sock >= 0)

Signature · 1 line

1.7.4.1

Chuck Lever:

Quoted 11 lines

Hi MJ-

Quoted 6 lines · Mi Jinlong

At RHEL, if user set port for mountd at /etc/services as
"mount 12345/tcp", mountd should be bind to 12345, but the
latest nfs-utils, mountd get a rand port, not 12345.

This patch make sure mountd be bind to the port which was set at /etc/service.

Quoted 3 lines

I don't think this is documented anywhere. Is there a reason it should work this way?

The typical way to set mountd's port is to use a command line option. That's the way it works for all the other RPC daemons. By default the ports are set up at random and registered with rpcbind. That's why clients use rpcbind, and not /etc/services, to find these services.

I don't have a depth research, agree with you.
But I got different result when I set port for mountd at /etc/services between nfs-utils-1.2.3 and nfs-utils-1.2.2.

I just think we should get the same result at new nfs-utils as older.

Quoted 13 lines

Chuck Lever:

Quoted 10 lines

Hi MJ-

Quoted 6 lines · Mi Jinlong

At RHEL, if user set port for mountd at /etc/services as
"mount 12345/tcp", mountd should be bind to 12345, but the
latest nfs-utils, mountd get a rand port, not 12345.

This patch make sure mountd be bind to the port which was set at /etc/service.

Quoted 6 lines

Quoted 3 lines

I don't think this is documented anywhere. Is there a reason it should work this way?

The typical way to set mountd's port is to use a command line option. That's the way it works for all the other RPC daemons. By default the ports are set up at random and registered with rpcbind. That's why clients use rpcbind, and not /etc/services, to find these services.

I don't have a depth research, agree with you.
But I got different result when I set port for mountd at /etc/services between nfs-utils-1.2.3 and nfs-utils-1.2.2.

IMO that's unintentional behavior. Could I ask a favor: would you bisect nfs-utils to find out exactly where this started and ended?

Quoted 2 lines

I just think we should get the same result at new nfs-utils as older.

Is there a real-world use case for this feature? Why isn't the command line option adequate?

Chuck Lever:

Quoted 14 lines · Mi Jinlong

Quoted 13 lines

Chuck Lever:

Quoted 10 lines

Hi MJ-

Quoted 6 lines · Mi Jinlong

At RHEL, if user set port for mountd at /etc/services as
"mount 12345/tcp", mountd should be bind to 12345, but the
latest nfs-utils, mountd get a rand port, not 12345.

This patch make sure mountd be bind to the port which was set at /etc/service.

Quoted 8 lines

Quoted 6 lines

Quoted 3 lines

I don't think this is documented anywhere. Is there a reason it should work this way?

The typical way to set mountd's port is to use a command line option. That's the way it works for all the other RPC daemons. By default the ports are set up at random and registered with rpcbind. That's why clients use rpcbind, and not /etc/services, to find these services.

I don't have a depth research, agree with you.
But I got different result when I set port for mountd at /etc/services between nfs-utils-1.2.3 and nfs-utils-1.2.2.

IMO that's unintentional behavior. Could I ask a favor: would you bisect nfs-utils to find out exactly where this started and ended?

Hi Chuck,

It's after your patch "mountd: Support TI-RPC mountd listener" (commit id:b551b1fd0052de9b8c674b30c39d9f2a1e9d79cc).

Before this patch, mountd call rpc_init to create rpc socket, after it, if HAVE_LIBTIRPC is defined, mountd will call nfs_svc_create to create rpc socket, that appears.

Quoted 6 lines

Quoted 3 lines

I just think we should get the same result at new nfs-utils as older.

Is there a real-world use case for this feature? Why isn't the command line option adequate?

I have a test site which depend on this feature.
If this feature indeed unnecessary, I will try to modify my test site.

Quoted 25 lines

Chuck Lever:

Quoted 13 lines · Mi Jinlong

Quoted 12 lines

Chuck Lever:

Quoted 10 lines

Hi MJ-

Quoted 6 lines · Mi Jinlong

At RHEL, if user set port for mountd at /etc/services as
"mount 12345/tcp", mountd should be bind to 12345, but the
latest nfs-utils, mountd get a rand port, not 12345.

This patch make sure mountd be bind to the port which was set at /etc/service.

Quoted 7 lines

Quoted 6 lines

Quoted 3 lines

I don't think this is documented anywhere. Is there a reason it should work this way?

The typical way to set mountd's port is to use a command line option. That's the way it works for all the other RPC daemons. By default the ports are set up at random and registered with rpcbind. That's why clients use rpcbind, and not /etc/services, to find these services.

I don't have a depth research, agree with you.
But I got different result when I set port for mountd at /etc/services between nfs-utils-1.2.3 and nfs-utils-1.2.2.

IMO that's unintentional behavior. Could I ask a favor: would you bisect nfs-utils to find out exactly where this started and ended?

Hi Chuck,

Quoted 6 lines

It's after your patch "mountd: Support TI-RPC mountd listener" (commit id:b551b1fd0052de9b8c674b30c39d9f2a1e9d79cc).

Before this patch, mountd call rpc_init to create rpc socket, after it, if HAVE_LIBTIRPC is defined, mountd will call nfs_svc_create to create rpc socket, that appears.

Thanks. I don't immediately see how that code path consults /etc/services. There are no calls to getservby{name,port}(3) in either mountd or in libtirpc. Did I miss something? Any idea?

You said it stopped working after a while. Can you bisect that as well?

Note that if nfs-utils is built without TI-RPC support, rpc_init() is still used instead of nfs_svc_create(). If nfs_svc_create() is indeed the proximal cause of this behavior, mountd won't consult /etc/services if it is built without TI-RPC support. So it might be a bug if this works for some build configurations and doesn't work for others. The question is should it always work, or should it never work; see below.

Quoted 5 lines

Quoted 3 lines

Quoted 1 line

I just think we should get the same result at new nfs-utils as older.

Is there a real-world use case for this feature? Why isn't the command line option adequate?

I have a test site which depend on this feature.
If this feature indeed unnecessary, I will try to modify my test site.

Without knowing more about your test site, I claim it can and should use the "-p" option on rpc.mountd. If your distribution of choice is Red Hat-based, you can set this in /etc/sysconfig/nfs (see MOUNTD_PORT=).

In other words, we have a documented and supported mechanism now, that should always work, for setting mountd's listener port. Can you explain in detail why allowing /etc/services to have this effect is also necessary?

Chuck Lever :

Quoted 1 line

In other words, we have a documented and supported mechanism now, that should always work, for setting mountd's listener port. Can you explain in detail why allowing /etc/services to have this effect is also necessary?

I just think the new nfs-utils should do the same thing as older one. Maybe called backward compatibility.

Mi Jinlong wrote:

At RHEL, if user set port for mountd at /etc/services as
"mount 12345/tcp", mountd should be bind to 12345, but the
latest nfs-utils, mountd get a rand port, not 12345.

This patch make sure mountd be bind to the port which was set at /etc/service.

Is this really such a good idea? I would find this behavior surprising.

I expect listeners to either use a well-known port, in which case they look in /etc/services and fall back to a compiled-in constant (like telnet or ftp), or use an ephemeral port, in which case they don't even look at /etc/services. This patch would change mountd so that its behavior (well-known versus ephemeral) depends on /etc/services rather than a run-time option.

The change in behavior would not be immediately obvious, either, because who is going to notice that mountd is now on a well-known port?

You could argue that the admin would have to add a line to /etc/services for anything to change, and I guess I could be convinced. But are you sure some distro packaging person isn't going to put that line in without understanding the implications?

Yes, I know putting mountd on a random port isn't going to thwart a determined hacker. I'm thinking of the nuisance factor. Consider ssh. It's a secure protocol, so there isn't really a security risk with leaving it on port 22, but sometimes you have to move it off to keep the log files from filling up with crap.

Here's an alternate proposal. Have the "-p" option take either a number or a name. If it's a name, look it up in /etc/services.

Chuck Lever wrote:

So, we could also address this by getting rid of the legacy RPC behavior instead. However, in cases like this, I typically choose to stick with legacy behavior, since that improves backwards compatibility. It already works like this for legacy RPC builds, so in some sense we are stuck with it.

Ok. I remember the earlier discussion but forgot that the patch simply restores older behavior that was changed by tirpc. In that case I'll go along with Mi's patch.

Quoted 11 lines

Chuck Lever wrote:

So, we could also address this by getting rid of the legacy RPC behavior instead. However, in cases like this, I typically choose to stick with legacy behavior, since that improves backwards compatibility. It already works like this for legacy RPC builds, so in some sense we are stuck with it.

Ok. I remember the earlier discussion but forgot that the patch simply restores older behavior that was changed by tirpc. In that case I'll go along with Mi's patch.

I am all for restoring the older behavior, but unfortunately this patch does not do it.

I when back and took a look at how the nfs-utils-1.2.2 code worked. While its true both mountd and statd read ports from /etc/service, they did not fail when those ports were already taken. They just bound to random ephemeral ports, which is probably the reason none of us noticed they were reading ports out of /etc/services. With Mi's patch, both daemons fail when the ports in /etc/service are already taken.

At RHEL, if user set port for mountd at /etc/services as
"mount 12345/tcp", mountd should be bind to 12345, but the
latest nfs-utils, mountd get a rand port, not 12345.

This patch make sure mountd be bind to the port which was set at /etc/service.

Signed-off-by Mi Jinlong <[email protected]>

---
 support/include/rpcmisc.h |    1 +
 support/nfs/svc_create.c  |    9 ++++-
 support/nfs/svc_socket.c  |   80 +++++++++++++++++++++------------------------
 utils/mountd/mountd.man   |    5 ++-
 utils/statd/statd.man     |    5 ++-
 5 files changed, 53 insertions(+), 47 deletions(-)

support/include/rpcmisc.h +1 -0

index 0b06457..b806227 100644
@@ -53,6 +53,7 @@ void		rpc_init(char *name, int prog, int vers,
 void		rpc_dispatch(struct svc_req *rq, SVCXPRT *xprt,
 				struct rpc_dtable *dtable, int nvers,
 				void *argp, void *resp);
+int		getservport(u_long number, const char *proto);
 
 extern int	_rpcpmstart;
 extern int	_rpcfdtype;

support/nfs/svc_create.c +7 -2

index b3f75ed..c159fc8 100644
@@ -393,7 +393,7 @@ nfs_svc_create(char *name, const rpcprog_t program, const rpcvers_t version,
 	const struct sigaction create_sigaction = {
 		.sa_handler	= SIG_IGN,
 	};
-	unsigned int visible, up;
+	unsigned int visible, up, servport;
 	struct netconfig *nconf;
 	void *handlep;
 

@@ -417,8 +417,13 @@ nfs_svc_create(char *name, const rpcprog_t program, const rpcvers_t version,
 		if (!(nconf->nc_flag & NC_VISIBLE))
 			continue;
 		visible++;
+		if (port == 0)
+			servport = getservport(program, nconf->nc_proto);
+		else
+			servport = port;
+
 		up += svc_create_nconf(name, program, version, dispatch,
-						port, nconf);
+						servport, nconf);
 	}
 
 	if (visible == 0)

support/nfs/svc_socket.c +37 -43

index 03a5325..c252f53 100644
@@ -35,14 +35,43 @@
 # define __close(f)		close ((f))
 #endif
 
+int getservport(u_long number, const char *proto)
+{
+	char rpcdata[1024], servdata[1024];
+	struct rpcent rpcbuf, *rpcp;
+	struct servent servbuf, *servp = NULL;
+	int ret;
+
+	ret = getrpcbynumber_r(number, &rpcbuf, rpcdata, sizeof rpcdata,
+				&rpcp);
+	if (ret == 0 && rpcp != NULL) {
+		/* First try name.  */
+		ret = getservbyname_r(rpcp->r_name, proto, &servbuf, servdata,
+					sizeof servdata, &servp);
+		if ((ret != 0 || servp == NULL) && rpcp->r_aliases) {
+			const char **a;
+
+			/* Then we try aliases.  */
+			for (a = (const char **) rpcp->r_aliases; *a != NULL; a++) {
+				ret = getservbyname_r(*a, proto, &servbuf, servdata,
+							sizeof servdata, &servp);
+				if (ret == 0 && servp != NULL)
+					break;
+			}
+		}
+	}
+
+	if (ret == 0 && servp != NULL)
+		return ntohs(servp->s_port);
+
+	return 0;
+}
+
 static int
 svc_socket (u_long number, int type, int protocol, int reuse)
 {
   struct sockaddr_in addr;
   socklen_t len = sizeof (struct sockaddr_in);
-  char rpcdata [1024], servdata [1024];
-  struct rpcent rpcbuf, *rpcp;
-  struct servent servbuf, *servp = NULL;
   int sock, ret;
   const char *proto = protocol == IPPROTO_TCP ? "tcp" : "udp";
 

@@ -66,48 +95,13 @@ svc_socket (u_long number, int type, int protocol, int reuse)
 
   memset (&addr, 0, sizeof (addr));
   addr.sin_family = AF_INET;
+  addr.sin_port = htons(getservport(number, proto));
 
-  ret = getrpcbynumber_r (number, &rpcbuf, rpcdata, sizeof rpcdata,
-			  &rpcp);
-  if (ret == 0 && rpcp != NULL)
-    {
-      /* First try name.  */
-      ret = getservbyname_r (rpcp->r_name, proto, &servbuf, servdata,
-			     sizeof servdata, &servp);
-      if ((ret != 0 || servp == NULL) && rpcp->r_aliases)
-	{
-	  const char **a;
-
-	  /* Then we try aliases.  */
-	  for (a = (const char **) rpcp->r_aliases; *a != NULL; a++) 
-	    {
-	      ret = getservbyname_r (*a, proto, &servbuf, servdata,
-				     sizeof servdata, &servp);
-	      if (ret == 0 && servp != NULL)
-		break;
-	    }
-	}
-    }
-
-  if (ret == 0 && servp != NULL)
+  if (bind(sock, (struct sockaddr *) &addr, len) < 0)
     {
-      addr.sin_port = servp->s_port;
-      if (bind (sock, (struct sockaddr *) &addr, len) < 0)
-	{
-	  perror (_("svc_socket: bind problem"));
-	  (void) __close (sock);
-	  sock = -1;
-	}
-    }
-  else
-    {
-	  addr.sin_port = 0;
-	  if (bind (sock, (struct sockaddr *) &addr, len) < 0)
-	    {
-	      perror (_("svc_socket: bind problem"));
-	      (void) __close (sock);
-	      sock = -1;
-	    }
+      perror (_("svc_socket: bind problem"));
+      (void) __close(sock);
+      sock = -1;
     }
 
   if (sock >= 0)

utils/mountd/mountd.man +4 -1

index 016a357..b322437 100644
@@ -122,7 +122,10 @@ Ignored (compatibility with unfsd??).
 Specifies the port number used for RPC listener sockets.
 If this option is not specified,
 .B rpc.mountd
-chooses a random ephemeral port for each listener socket.
+will try to consult
+.IR /etc/services ,
+if gets port succeed, set the same port for all listener socket,
+otherwise chooses a random ephemeral port for each listener socket.
 .IP
 This option can be used to fix the port value of
 .BR rpc.mountd 's

utils/statd/statd.man +4 -1

index b72236c..203f8c9 100644
@@ -219,7 +219,10 @@ for details.
 Specifies the port number used for RPC listener sockets.
 If this option is not specified,
 .B rpc.statd
-chooses a random ephemeral port for each listener socket.
+will try to consult
+.IR /etc/services ,
+if gets port succeed, set the same port for all listener socket,
+otherwise chooses a random ephemeral port for each listener socket.
 .IP
 This option can be used to fix the port value of its listeners when
 SM_NOTIFY requests must traverse a firewall between clients and servers.