[PATCH 05/17] libfshelp: add translator-list.c

[Justus Winter]

---
 libfshelp/Makefile          |    3 +-
 libfshelp/fshelp.h          |   21 ++++++
 libfshelp/translator-list.c |  161 +++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 184 insertions(+), 1 deletion(-)
 create mode 100644 libfshelp/translator-list.c

diff --git a/libfshelp/Makefile b/libfshelp/Makefile
index 4de3837..6ba6a14 100644
--- a/libfshelp/Makefile
+++ b/libfshelp/Makefile
@@ -20,6 +20,7 @@ makemode := library
 
 libname = libfshelp
 SRCS = lock-acquire.c lock-init.c \
+       translator-list.c \
        start-translator-long.c start-translator.c \
        fetch-root.c transbox-init.c set-active.c fetch-control.c \
        drop-transbox.c translated.c \
@@ -32,7 +33,7 @@ SRCS =        lock-acquire.c lock-init.c \
        touch.c
 installhdrs = fshelp.h
 
-HURDLIBS = shouldbeinlibc iohelp ports
+HURDLIBS = shouldbeinlibc iohelp ports ihash
 LDLIBS += -lpthread
 OBJS = $(subst .c,.o,$(SRCS))
 
diff --git a/libfshelp/fshelp.h b/libfshelp/fshelp.h
index cf39fbc..37f4e82 100644
--- a/libfshelp/fshelp.h
+++ b/libfshelp/fshelp.h
@@ -32,6 +32,27 @@
 #include <maptime.h>
 
 
+/* XXX */
+/* XXX */
+
+/* XXX  */
+error_t
+fshelp_set_active_translator (const char *name, mach_port_t active);
+
+/* XXX  */
+error_t
+fshelp_remove_active_translator (mach_port_t active);
+
+/* XXX */
+typedef error_t (*fshelp_filter) (const char *path);
+
+/* XXX */
+error_t
+fshelp_get_active_translators (char **translators,
+                              size_t *translators_len,
+                              fshelp_filter filter);
+
+
 /* Passive translator linkage */
 /* These routines are self-contained and start passive translators,
    returning the control port.  They do not require multi threading
diff --git a/libfshelp/translator-list.c b/libfshelp/translator-list.c
new file mode 100644
index 0000000..a04f424
--- /dev/null
+++ b/libfshelp/translator-list.c
@@ -0,0 +1,161 @@
+/*
+   Copyright (C) 2013 Free Software Foundation
+   Written by Justus Winter <4winter@informatik.uni-hamburg.de>
+
+   This file is part of the GNU Hurd.
+
+   This program is free software; you can redistribute it and/or
+   modify it under the terms of the GNU General Public License as
+   published by the Free Software Foundation; either version 2, or (at
+   your option) any later version.
+
+   This program is distributed in the hope that it will be useful, but
+   WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.         See the GNU
+   General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
+
+#include <argz.h>
+#include <hurd/fsys.h>
+#include <hurd/ihash.h>
+#include <mach.h>
+#include <mach/notify.h>
+#include <pthread.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "fshelp.h"
+
+struct translator
+{
+  char *name;
+  mach_port_t active;
+};
+
+/* XXX */
+static struct hurd_ihash translator_ihash
+  = HURD_IHASH_INITIALIZER (HURD_IHASH_NO_LOCP);
+
+static pthread_mutex_t translator_ihash_lock = PTHREAD_MUTEX_INITIALIZER;
+
+/* XXX */
+static void
+translator_ihash_cleanup (void *element, void *arg)
+{
+  /* XXX: No need to deallocate port, we only keep a "weak"
+     reference.         */
+  free (element);
+}
+
+error_t
+fshelp_set_active_translator (const char *name, mach_port_t active)
+{
+  error_t err = 0;
+  pthread_mutex_lock (&translator_ihash_lock);
+
+  if (! translator_ihash.cleanup)
+    hurd_ihash_set_cleanup (&translator_ihash, translator_ihash_cleanup, NULL);
+
+  struct translator *t = NULL;
+  HURD_IHASH_ITERATE (&translator_ihash, value)
+    {
+      t = value;
+      if (strcmp (name, t->name) == 0)
+       goto update; /* Entry exists. */
+    }
+
+  t = malloc (sizeof (struct translator));
+  if (! t)
+    return ENOMEM;
+
+  t->active = MACH_PORT_NULL;
+  t->name = strdup (name);
+  if (! t->name)
+    {
+      err = errno;
+      free (t);
+      goto out;
+    }
+
+  err = hurd_ihash_add (&translator_ihash, (hurd_ihash_key_t) t, t);
+  if (err)
+    goto out;
+
+ update:
+  if (active)
+    /* XXX: No need to increment the reference count, we only keep a
+       "weak" reference.  */
+    t->active = active;
+  else
+    hurd_ihash_remove (&translator_ihash, (hurd_ihash_key_t) t);
+
+ out:
+  pthread_mutex_unlock (&translator_ihash_lock);
+  return err;
+}
+
+error_t
+fshelp_remove_active_translator (mach_port_t active)
+{
+  error_t err = 0;
+  pthread_mutex_lock (&translator_ihash_lock);
+
+  struct translator *t = NULL;
+  HURD_IHASH_ITERATE (&translator_ihash, value)
+    {
+      struct translator *v = value;
+      if (active == v->active)
+       {
+         t = v;
+         break;
+       }
+    }
+
+  if (t)
+    hurd_ihash_remove (&translator_ihash, (hurd_ihash_key_t) t);
+
+  pthread_mutex_unlock (&translator_ihash_lock);
+  return err;
+}
+
+error_t
+fshelp_get_active_translators (char **translators,
+                              size_t *translators_len,
+                              fshelp_filter filter)
+{
+  error_t err = 0;
+  pthread_mutex_lock (&translator_ihash_lock);
+
+  HURD_IHASH_ITERATE (&translator_ihash, value)
+    {
+      struct translator *t = value;
+      if (filter)
+       {
+         char *dir = strdup (t->name);
+         if (! dir)
+           {
+             err = ENOMEM;
+             break;
+           }
+
+         err = filter (dirname (dir));
+         free (dir);
+         if (err)
+           {
+             err = 0;
+             continue; /* Skip this entry.  */
+           }
+       }
+
+      err = argz_add (translators, translators_len,
+                     t->name);
+      if (err)
+       break;
+    }
+
+  pthread_mutex_unlock (&translator_ihash_lock);
+  return err;
+}
-- 
1.7.10.4