[hurd] 10/15: libfshelp: Use node instead of name as key.

[Samuel Thibault]

This is an automated email from the git hooks/post-receive script.

sthibault pushed a commit to branch dde
in repository hurd.

commit e08859424e01697fe556e277283e8e1905327ce7
Author: Justus Winter <address@hidden>
Date:   Tue Aug 22 13:07:54 2017 +0200

    libfshelp: Use node instead of name as key.
    
    Previously, libfshelp used the name of an translator as key in the
    hash table.  This however is flawed, because a translator is bound to
    a node, and a node can have zero or more links in the file system.
    Use the nodes address (or rather, the address of the transbox embedded
    in the node) as key instead.
    
    * libfshelp/fshelp.h (fshelp_set_active_translator): Instead of the
    control port, hand the whole transbox to the function.
    * libfshelp/translator-list.c (struct translator): New field 'locp'.
    (hash): Hash pointer.
    (compare): Compare pointer.
    (translator_ihash): Use an location pointer.
    (fshelp_set_active_translator): Use the address of the transbox as key.
    (fshelp_remove_active_translator): Remove using the location pointer.
    * libdiskfs/dir-lookup.c (diskfs_S_dir_lookup): Fix callsite.
    * libdiskfs/file-set-trans.c (diskfs_S_file_set_translator): Likewise.
    * libnetfs/dir-lookup.c (netfs_S_dir_lookup): Likewise.
    * libnetfs/file-set-translator.c (netfs_S_file_set_translator):
    Likewise.
---
 libdiskfs/dir-lookup.c         |  2 +-
 libdiskfs/file-set-trans.c     |  2 +-
 libfshelp/fshelp.h             | 10 ++++-----
 libfshelp/translator-list.c    | 50 ++++++++++++++++++++++--------------------
 libnetfs/dir-lookup.c          |  2 +-
 libnetfs/file-set-translator.c |  2 +-
 6 files changed, 35 insertions(+), 33 deletions(-)

diff --git a/libdiskfs/dir-lookup.c b/libdiskfs/dir-lookup.c
index a0c368b..eafeefc 100644
--- a/libdiskfs/dir-lookup.c
+++ b/libdiskfs/dir-lookup.c
@@ -315,7 +315,7 @@ diskfs_S_dir_lookup (struct protid *dircred,
 
                err = fshelp_set_active_translator (&newpi->pi,
                                                    complete_path,
-                                                   np->transbox.active);
+                                                   &np->transbox);
                if (complete_path != translator_path)
                  free(complete_path);
                if (err)
diff --git a/libdiskfs/file-set-trans.c b/libdiskfs/file-set-trans.c
index 6a73e23..de52ba4 100644
--- a/libdiskfs/file-set-trans.c
+++ b/libdiskfs/file-set-trans.c
@@ -222,7 +222,7 @@ diskfs_S_file_set_translator (struct protid *cred,
   pthread_mutex_unlock (&np->lock);
 
   if (! err && cred->po->path && active_flags & FS_TRANS_SET)
-    err = fshelp_set_active_translator (&cred->pi, cred->po->path, active);
+    err = fshelp_set_active_translator (&cred->pi, cred->po->path, 
&np->transbox);
 
   return err;
 }
diff --git a/libfshelp/fshelp.h b/libfshelp/fshelp.h
index d1dd49c..7663ba1 100644
--- a/libfshelp/fshelp.h
+++ b/libfshelp/fshelp.h
@@ -38,16 +38,16 @@
    require multi threading but depend on the ports library.  */
 
 struct port_info;
+struct transbox;
 
 /* Record an active translator being bound to the given file name
-   NAME.  ACTIVE is the control port of the translator.  PI references
-   a receive port that is used to request dead name notifications,
-   typically the port for the underlying node passed to the
-   translator.  */
+   NAME.  TRANSBOX is the nodes transbox.  PI references a receive
+   port that is used to request dead name notifications, typically the
+   port for the underlying node passed to the translator.  */
 error_t
 fshelp_set_active_translator (struct port_info *pi,
                              const char *name,
-                             mach_port_t active);
+                             const struct transbox *transbox);
 
 /* Remove the active translator specified by its control port ACTIVE.
    If there is no active translator with the given control port, this
diff --git a/libfshelp/translator-list.c b/libfshelp/translator-list.c
index a360330..7077b21 100644
--- a/libfshelp/translator-list.c
+++ b/libfshelp/translator-list.c
@@ -35,9 +35,13 @@
 
 struct translator
 {
-  struct port_info *pi;
-  char *name;
-  mach_port_t active;
+  hurd_ihash_locp_t locp;      /* Slot in the hash table.  */
+  struct port_info *pi;                /* We get dead-name notifications
+                                  here.  */
+  char *name;                  /* The path to the node the translator
+                                  is bound to, relative to the root.
+                                  This is a best effort.  */
+  mach_port_t active;          /* Translator control port.  */
 };
 
 /* The hash table requires some callback functions.  */
@@ -56,41 +60,43 @@ cleanup (void *value, void *arg)
 static hurd_ihash_key_t
 hash (const void *key)
 {
-  return (hurd_ihash_key_t) hurd_ihash_hash32 (key, strlen (key), 0);
+  return (hurd_ihash_key_t) hurd_ihash_hash32 (key, sizeof (void *), 0);
 }
 
 static int
 compare (const void *a, const void *b)
 {
-  return strcmp ((const char *) a, (const char *) b) == 0;
+  return *(void **) a == *(void **) b;
 }
 
 /* The list of active translators.  */
 static struct hurd_ihash translator_ihash
-  = HURD_IHASH_INITIALIZER_GKI (HURD_IHASH_NO_LOCP, cleanup, NULL,
-                               hash, compare);
+  = HURD_IHASH_INITIALIZER_GKI (offsetof (struct translator, locp),
+                               cleanup, NULL, hash, compare);
 
 /* The lock protecting the translator_ihash.  */
 static pthread_mutex_t translator_ihash_lock = PTHREAD_MUTEX_INITIALIZER;
 
 /* Record an active translator being bound to the given file name
-   NAME.  ACTIVE is the control port of the translator.  */
+   NAME.  TRANSBOX is the nodes transbox.  PI references a receive
+   port that is used to request dead name notifications, typically the
+   port for the underlying node passed to the translator.  */
 error_t
 fshelp_set_active_translator (struct port_info *pi,
                              const char *name,
-                             mach_port_t active)
+                             const struct transbox *transbox)
 {
   error_t err = 0;
   struct translator *t;
   hurd_ihash_locp_t slot;
 
   pthread_mutex_lock (&translator_ihash_lock);
-  t = hurd_ihash_locp_find (&translator_ihash, (hurd_ihash_key_t) name,
+  t = hurd_ihash_locp_find (&translator_ihash, (hurd_ihash_key_t) transbox,
                            &slot);
   if (t)
     goto update; /* Entry exists.  */
 
-  if (! MACH_PORT_VALID (active))
+  if (! MACH_PORT_VALID (transbox->active))
     /* Avoid allocating an entry just to delete it.  */
     goto out;
 
@@ -112,7 +118,7 @@ fshelp_set_active_translator (struct port_info *pi,
     }
 
   err = hurd_ihash_locp_add (&translator_ihash, slot,
-                            (hurd_ihash_key_t) t->name, t);
+                            (hurd_ihash_key_t) transbox, t);
   if (err)
     {
       free (t->name);
@@ -121,17 +127,17 @@ fshelp_set_active_translator (struct port_info *pi,
     }
 
  update:
-  if (MACH_PORT_VALID (active) && active != t->active)
+  if (MACH_PORT_VALID (transbox->active) && transbox->active != t->active)
     {
       mach_port_t old;
-      err = mach_port_request_notification (mach_task_self (), active,
+      err = mach_port_request_notification (mach_task_self (), 
transbox->active,
                                            MACH_NOTIFY_DEAD_NAME, 0,
                                            pi->port_right,
                                            MACH_MSG_TYPE_MAKE_SEND_ONCE,
                                            &old);
       if (err)
        goto out;
-      if (old != MACH_PORT_NULL)
+      if (MACH_PORT_VALID (old))
        mach_port_deallocate (mach_task_self (), old);
 
       if (t->pi)
@@ -142,14 +148,14 @@ fshelp_set_active_translator (struct port_info *pi,
 
       if (MACH_PORT_VALID (t->active))
        mach_port_deallocate (mach_task_self (), t->active);
-      mach_port_mod_refs (mach_task_self (), active,
+      mach_port_mod_refs (mach_task_self (), transbox->active,
                          MACH_PORT_RIGHT_SEND, +1);
-      t->active = active;
+      t->active = transbox->active;
     }
-  else if (! MACH_PORT_VALID (active))
+  else if (! MACH_PORT_VALID (transbox->active))
     {
       int ok;
-      ok = hurd_ihash_remove (&translator_ihash, (hurd_ihash_key_t) t->name);
+      ok = hurd_ihash_remove (&translator_ihash, (hurd_ihash_key_t) transbox);
       assert_backtrace (ok);
     }
 
@@ -179,11 +185,7 @@ fshelp_remove_active_translator (mach_port_t active)
     }
 
   if (t)
-    {
-      int ok;
-      ok = hurd_ihash_remove (&translator_ihash, (hurd_ihash_key_t) t->name);
-      assert_backtrace (ok);
-    }
+    hurd_ihash_locp_remove (&translator_ihash, t->locp);
 
   pthread_mutex_unlock (&translator_ihash_lock);
   return err;
diff --git a/libnetfs/dir-lookup.c b/libnetfs/dir-lookup.c
index bfac2ac..a135917 100644
--- a/libnetfs/dir-lookup.c
+++ b/libnetfs/dir-lookup.c
@@ -306,7 +306,7 @@ netfs_S_dir_lookup (struct protid *dircred,
 
                err = fshelp_set_active_translator (&newpi->pi,
                                                    complete_path,
-                                                   np->transbox.active);
+                                                   &np->transbox);
                if (complete_path != translator_path)
                  free(complete_path);
                if (err)
diff --git a/libnetfs/file-set-translator.c b/libnetfs/file-set-translator.c
index bac950e..2b71848 100644
--- a/libnetfs/file-set-translator.c
+++ b/libnetfs/file-set-translator.c
@@ -178,7 +178,7 @@ netfs_S_file_set_translator (struct protid *user,
     }
 
   if (! err && user->po->path && active_flags & FS_TRANS_SET)
-    err = fshelp_set_active_translator (&user->pi, user->po->path, active);
+    err = fshelp_set_active_translator (&user->pi, user->po->path, 
&np->transbox);
 
  out:
   pthread_mutex_unlock (&np->lock);

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