[nfs-utils,1/3] rpc.mountd: set nonblocking mode if no libtirpc

Commit Message

Bodo Stroesser Nov. 5, 2014, 8:22 p.m. UTC

From: Bodo Stroesser <[e-mail]>
Date: Thu, 09 Oct 2014 13:06:19 +0200
Subject: [nfs-utils] [PATCH 1/3] rpc.mountd: set nonblocking mode if no libtirpc

If mountd is built without libtirpc and it is started using "-p XXX" option,
the tcp listeners and the sockets waiting for UDP messages are not in
non-blocking mode. Thus if running with multiple threads (-t XX),
all threads will wake up from select on a connection request or a UDP message,
but only one thread will succeed. All others will wait on accept() or read()
for the next event.

Signed-off-by: Bodo Stroesser <[e-mail]>
---

Patch

--- nfs-utils-1.3.1/support/include/nfslib.h	2014-10-09 12:52:30.000000000 +0200
+++ nfs-utils-1.3.1/support/include/nfslib.h	2014-10-09 12:53:37.000000000 +0200
@@ -174,6 +174,7 @@  void closeall(int min);
 
 int			svctcp_socket (u_long __number, int __reuse);
 int			svcudp_socket (u_long __number);
+int			svcsock_nonblock (int __sock);
 
 /* Misc shared code prototypes */
 size_t  strlcat(char *, const char *, size_t);
--- nfs-utils-1.3.1/support/nfs/svc_socket.c	2014-10-09 12:56:14.000000000 +0200
+++ nfs-utils-1.3.1/support/nfs/svc_socket.c	2014-10-09 13:10:44.000000000 +0200
@@ -76,6 +76,39 @@  int getservport(u_long number, const cha
 	return 0;
 }
 
+int
+svcsock_nonblock(int sock)
+{
+	int flags;
+
+	if (sock < 0)
+		return sock;
+
+	/* This socket might be shared among multiple processes
+	 * if mountd is run multi-threaded.  So it is safest to
+	 * make it non-blocking, else all threads might wake
+	 * one will get the data, and the others will block
+	 * indefinitely.
+	 * In all cases, transaction on this socket are atomic
+	 * (accept for TCP, packet-read and packet-write for UDP)
+	 * so O_NONBLOCK will not confuse unprepared code causing
+	 * it to corrupt messages.
+	 * It generally safest to have O_NONBLOCK when doing an accept
+	 * as if we get a RST after the SYN and before accept runs,
+	 * we can block despite being told there was an acceptable
+	 * connection.
+	 */
+	if ((flags = fcntl(sock, F_GETFL)) < 0)
+		perror(_("svc_socket: can't get socket flags"));
+	else if (fcntl(sock, F_SETFL, flags|O_NONBLOCK) < 0)
+		perror(_("svc_socket: can't set socket flags"));
+	else
+		return sock;
+
+	(void) __close(sock);
+	return -1;
+}
+
 static int
 svc_socket (u_long number, int type, int protocol, int reuse)
 {
@@ -113,38 +146,7 @@  svc_socket (u_long number, int type, int
       sock = -1;
     }
 
-  if (sock >= 0)
-    {
-	    /* This socket might be shared among multiple processes
-	     * if mountd is run multi-threaded.  So it is safest to
-	     * make it non-blocking, else all threads might wake
-	     * one will get the data, and the others will block
-	     * indefinitely.
-	     * In all cases, transaction on this socket are atomic
-	     * (accept for TCP, packet-read and packet-write for UDP)
-	     * so O_NONBLOCK will not confuse unprepared code causing
-	     * it to corrupt messages.
-	     * It generally safest to have O_NONBLOCK when doing an accept
-	     * as if we get a RST after the SYN and before accept runs,
-	     * we can block despite being told there was an acceptable
-	     * connection.
-	     */
-	int flags;
-	if ((flags = fcntl(sock, F_GETFL)) < 0)
-	  {
-	      perror (_("svc_socket: can't get socket flags"));
-	      (void) __close (sock);
-	      sock = -1;
-	  }
-	else if (fcntl(sock, F_SETFL, flags|O_NONBLOCK) < 0)
-	  {
-	      perror (_("svc_socket: can't set socket flags"));
-	      (void) __close (sock);
-	      sock = -1;
-	  }
-    }
-
-  return sock;
+  return svcsock_nonblock(sock);
 }
 
 /*
--- nfs-utils-1.3.1/support/nfs/rpcmisc.c	2014-10-08 21:22:04.000000000 +0200
+++ nfs-utils-1.3.1/support/nfs/rpcmisc.c	2014-10-08 21:22:36.000000000 +0200
@@ -104,7 +104,7 @@  makesock(int port, int proto)
 		return -1;
 	}
 
-	return sock;
+	return svcsock_nonblock(sock);
 }
 
 void