From: Samuel Thibault <samuel.thibault@gnu.org>
Date: Wed, 27 Aug 2014 22:11:54 +0000 (+0200)
Subject: Simplify atomicity of socket creation in bind.
X-Git-Tag: glibc-2.20~10
X-Git-Url: https://sourceware.org/git/?a=commitdiff_plain;h=b0f955c9ac70181532e93aa78c49c204c2a31dfd;p=glibc.git

Simplify atomicity of socket creation in bind.
---

diff --git a/ChangeLog b/ChangeLog
index 6261ed481c..8d1eef4558 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2014-08-27  Samuel Thibault  <samuel.thibault@ens-lyon.org>
+
+	Simplify atomicity of socket creation in bind.
+
+	* sysdeps/mach/hurd/bind.c (__bind): Use dir_lookup(node, "") instead of
+	looking up the name after linking the file.
+
 2014-08-27  Allan McRae  <allan@archlinux.org>
 
 	* sysdeps/i386/fpu/libm-test-ulps: Update ULPs.
diff --git a/sysdeps/mach/hurd/bind.c b/sysdeps/mach/hurd/bind.c
index 17ef22a7d0..9bd668c4e7 100644
--- a/sysdeps/mach/hurd/bind.c
+++ b/sysdeps/mach/hurd/bind.c
@@ -39,7 +39,7 @@ __bind  (int fd, __CONST_SOCKADDR_ARG addrarg, socklen_t len)
     {
       /* For the local domain, we must create a node in the filesystem
 	 using the ifsock translator and then fetch the address from it.  */
-      file_t dir, node;
+      file_t dir, node, ifsock;
       char name[len - offsetof (struct sockaddr_un, sun_path) + 1], *n;
 
       strncpy (name, addr->sun_path, sizeof name - 1);
@@ -63,36 +63,32 @@ __bind  (int fd, __CONST_SOCKADDR_ARG addrarg, socklen_t len)
 				       MACH_MSG_TYPE_COPY_SEND);
 	  if (! err)
 	    {
-	      /* Link the node, now a socket, into the target directory.  */
-	      err = __dir_link (dir, node, n, 1);
-	      if (err == EEXIST)
+	      enum retry_type doretry;
+	      char retryname[1024];
+	      /* Get a port to the ifsock translator.  */
+	      err = __dir_lookup (node, "", 0, 0, &doretry, retryname, &ifsock);
+	      if (! err && (doretry != FS_RETRY_NORMAL || retryname[0] != '\0'))
 		err = EADDRINUSE;
 	    }
-	  __mach_port_deallocate (__mach_task_self (), node);
 	  if (! err)
 	    {
-	      /* Get a port to the ifsock translator.  */
-	      file_t ifsock = __file_name_lookup_under (dir, n, 0, 0);
-	      if (ifsock == MACH_PORT_NULL)
+	      /* Get the address port.  */
+	      err = __ifsock_getsockaddr (ifsock, &aport);
+	      if (err == MIG_BAD_ID || err == EOPNOTSUPP)
+		err = EGRATUITOUS;
+	      if (! err)
 		{
-		  err = errno;
-		  /* If we failed, get rid of the node we created.  */
-		  __dir_unlink (dir, n);
-		}
-	      else
-		{
-		  /* Get the address port.  */
-		  err = __ifsock_getsockaddr (ifsock, &aport);
-		  if (err == MIG_BAD_ID || err == EOPNOTSUPP)
-		    /* We are not talking to /hurd/ifsock.  Probably
-		       someone came in after we linked our node, unlinked
-		       it, and replaced it with a different node, before we
-		       did our lookup.  Treat it as if our link had failed
-		       with EEXIST.  */
+		  /* Link the node, now a socket with proper mode, into the
+		     target directory.  */
+		  err = __dir_link (dir, node, n, 1);
+		  if (err == EEXIST)
 		    err = EADDRINUSE;
+		  if (err)
+		    __mach_port_deallocate (__mach_task_self (), aport);
 		}
 	      __mach_port_deallocate (__mach_task_self (), ifsock);
 	    }
+	  __mach_port_deallocate (__mach_task_self (), node);
 	}
       __mach_port_deallocate (__mach_task_self (), dir);