1998-12-27 Roland McGrath <roland@baalperazim.frob.com>

	Use a struct hurd_port for the cached exec server port,
	so it is properly reference-counted and locked.
	* boot-start.c (diskfs_exec): Variable removed.
	(diskfs_start_bootstrap): Make it a local here.
	Install that port in _diskfs_exec_portcell.
	(diskfs_S_fsys_init): Use _diskfs_exec_portcell instead
	of diskfs_exec.
	* init-init.c (_diskfs_exec_portcell): New variable.
	(diskfs_init_diskfs): Initialize it.
	* priv.h: Declare it.
	* diskfs.h (diskfs_exec, diskfs_exec_ctl): Remove decls.
	* file-exec.c (diskfs_S_file_exec): Use _diskfs_exec_portcell instead
	of diskfs_exec.

1 files changed, 38 insertions, 13 deletions

diff --git a/libdiskfs/file-exec.c b/libdiskfs/file-exec.c
index 2933a7d4..521f3528 100644
--- a/libdiskfs/file-exec.c
+++ b/libdiskfs/file-exec.c
@@ -54,16 +54,31 @@ diskfs_S_file_exec (struct protid *cred,
   int suid, sgid;
   struct protid *newpi;
   error_t err = 0;
+  mach_port_t execserver;
   int cached_exec;
+  struct hurd_userlink ulink;
+#define RETURN(code) do { err = (code); goto out; } while (0)
 
   if (!cred)
     return EOPNOTSUPP;
 
-  cached_exec = (diskfs_exec != MACH_PORT_NULL);
-  if (diskfs_exec == MACH_PORT_NULL)
-    diskfs_exec = file_name_lookup (_SERVERS_EXEC, 0, 0); /* XXX unlocked */
-  if (diskfs_exec == MACH_PORT_NULL)
-    return EOPNOTSUPP;
+  /* Get a light reference to the cached exec server port.  */
+  execserver = _hurd_port_get (&_diskfs_exec_portcell, &ulink);
+  cached_exec = (execserver != MACH_PORT_NULL);
+  if (execserver == MACH_PORT_NULL)
+    {
+      /* No cached port.  Look up the canonical naming point.  */
+      execserver = file_name_lookup (_SERVERS_EXEC, 0, 0);
+      if (execserver == MACH_PORT_NULL)
+	return EOPNOTSUPP;	/* No exec server, no exec.  */
+      else
+	{
+	  /* Install the newly-gotten exec server port for other
+	     threads to use, then get a light reference for this call.  */
+	  _hurd_port_set (&_diskfs_exec_portcell, execserver);
+	  execserver = _hurd_port_get (&_diskfs_exec_portcell, &ulink);
+	}
+    }
 
   np = cred->po->np;
 
@@ -74,17 +89,17 @@ diskfs_S_file_exec (struct protid *cred,
   mutex_unlock (&np->lock);
 
   if (_diskfs_noexec)
-    return EACCES;
+    RETURN (EACCES);
 
   if ((cred->po->openstat & O_EXEC) == 0)
-    return EBADF;
+    RETURN (EBADF);
 
   if (!((mode & (S_IXUSR|S_IXGRP|S_IXOTH))
 	|| ((mode & S_IUSEUNK) && (mode & (S_IEXEC << S_IUNKSHIFT)))))
-    return EACCES;
+    RETURN (EACCES);
 
   if ((mode & S_IFMT) == S_IFDIR)
-    return EACCES;
+    RETURN (EACCES);
 
   suid = mode & S_ISUID;
   sgid = mode & S_ISGID;
@@ -124,7 +139,7 @@ diskfs_S_file_exec (struct protid *cred,
     {
       do
 	{
-	  err = exec_exec (diskfs_exec,
+	  err = exec_exec (execserver,
 			   ports_get_right (newpi),
 			   MACH_MSG_TYPE_MAKE_SEND,
 			   task, flags, argv, argvlen, envp, envplen,
@@ -140,10 +155,17 @@ diskfs_S_file_exec (struct protid *cred,
 		  /* We were using a previously looked-up exec server port.
 		     Try looking up a new one before giving an error.  */
 		  cached_exec = 0;
-		  mach_port_deallocate (mach_task_self (), diskfs_exec);
-		  diskfs_exec = file_name_lookup (_SERVERS_EXEC, 0, 0);
-		  if (diskfs_exec == MACH_PORT_NULL)
+		  _hurd_port_free (&_diskfs_exec_portcell, &ulink, execserver);
+
+		  execserver = file_name_lookup (_SERVERS_EXEC, 0, 0);
+		  if (execserver == MACH_PORT_NULL)
 		    err = EOPNOTSUPP;
+		  else
+		    {
+		      _hurd_port_set (&_diskfs_exec_portcell, execserver);
+		      execserver = _hurd_port_get (&_diskfs_exec_portcell,
+						   &ulink);
+		    }
 		}
 	      else
 		err = EOPNOTSUPP;
@@ -163,5 +185,8 @@ diskfs_S_file_exec (struct protid *cred,
 	mach_port_deallocate (mach_task_self (), portarray[i]);
     }
 
+ out:
+  _hurd_port_free (&_diskfs_exec_portcell, &ulink, execserver);
+
   return err;
 }