From 748ef0df0ae891c65043a2a3c8d0f29cad358f5a Mon Sep 17 00:00:00 2001
From: Pino Toscano <toscano.pino@tiscali.it>
Date: Sat, 30 Mar 2013 15:28:07 +0100
Subject: Switch from __thread to pthread_key_t for fuse_context

This allows to properly cleanup the per-thread context.

* src/fuse_i.h (libfuse_ctx): Remove declaration.
* src/main.c (libfuse_ctx): Remove variable.
(libfuse_ctx_key): New variable.
(fuse_destroy_context): New function.
(fuse_create_key): Likewise.
(fuse_new): Use fuse_get_context instead of libfuse_ctx.
(fuse_get_context): Create fuse_create_key only once.  Allocate a new
struct fuse_context if needed, and return it.
* src/netfs.c (update_context_struct): Use fuse_get_context instead of
libfuse_ctx.
---
 src/fuse_i.h |  2 --
 src/main.c   | 45 ++++++++++++++++++++++++++++++++++++++++++---
 src/netfs.c  | 18 +-----------------
 3 files changed, 43 insertions(+), 22 deletions(-)

diff --git a/src/fuse_i.h b/src/fuse_i.h
index 472bc6503..851058d65 100644
--- a/src/fuse_i.h
+++ b/src/fuse_i.h
@@ -57,8 +57,6 @@ extern struct fuse *libfuse_fuse;
 #define FUSE_SYMVER(x) __asm__(x)
 
 
-extern __thread struct fuse_context *libfuse_ctx;
-
 extern void update_context_struct(struct iouser *cred, struct fuse *fuse);
 
 /*****************************************************************************
diff --git a/src/main.c b/src/main.c
index b8f25c8cd..345845cb0 100644
--- a/src/main.c
+++ b/src/main.c
@@ -35,7 +35,8 @@ struct _libfuse_params libfuse_params = { 0 };
 /* pointer to the fuse structure of this translator process */
 struct fuse *libfuse_fuse = NULL;
 
-__thread struct fuse_context *libfuse_ctx;
+/* the key for the fuse_context */
+static pthread_key_t libfuse_ctx_key;
 
 /* the port where to write out debug messages to, NULL to omit these */
 FILE *debug_port = NULL;
@@ -44,6 +45,25 @@ FILE *debug_port = NULL;
 static int fuse_bootstrap(const char *mountpoint);
 
 
+/* Destroy the fuse_context held as TSD.
+ */
+static void
+fuse_destroy_context(void *data)
+{
+  free(data);
+}
+
+
+/* Create the TSD key.
+ */
+static void
+fuse_create_key(void)
+{
+  int err = pthread_key_create(&libfuse_ctx_key, fuse_destroy_context);
+  assert_perror(err);
+}
+
+
 /* Interpret a __single__ mount option 
  * The option itself `opt' may be modified during this call.
  */
@@ -322,7 +342,7 @@ fuse_new(struct fuse_chan *ch, struct fuse_args *args,
   new->conn.max_readahead = UINT_MAX;
 
   update_context_struct(NULL, new);
-  libfuse_ctx->private_data = user_data;
+  fuse_get_context()->private_data = user_data;
 
   if(new->op.ops.init != NULL)
     {
@@ -582,7 +602,26 @@ fuse_exited(struct fuse *f)
 struct fuse_context *
 fuse_get_context(void)
 {
-  return libfuse_ctx;
+  static pthread_once_t libfuse_ctx_key_once = PTHREAD_ONCE_INIT;
+
+  pthread_once(&libfuse_ctx_key_once, fuse_create_key);
+
+  struct fuse_context *ctx = pthread_getspecific(libfuse_ctx_key);
+
+  if(! ctx)
+    {
+      ctx = calloc(1, sizeof(*ctx));
+      if(! ctx)
+	{
+	  fprintf(stderr, "Cannot allocate a new fuse_context\n");
+	  fprintf(stderr, "libfuse will abort now\n");
+	  abort();
+	}
+
+      pthread_setspecific(libfuse_ctx_key, ctx);
+    }
+
+  return ctx;
 }
 
 
diff --git a/src/netfs.c b/src/netfs.c
index a8718369c..9a11dfcf4 100644
--- a/src/netfs.c
+++ b/src/netfs.c
@@ -61,24 +61,8 @@ void
 update_context_struct(struct iouser *cred, struct fuse *fuse)
 {
   FUNC_PROLOGUE("refresh_context_struct");
-  struct fuse_context *ctx = libfuse_ctx;
+  struct fuse_context *ctx = fuse_get_context();
   
-  if(! ctx) 
-    {
-      ctx = malloc(sizeof(struct fuse_context));
-      if(! ctx) 
-	{
-	  perror(PACKAGE_NAME);
-	  return;
-	}
-
-      libfuse_ctx = ctx;
-
-      /* FIXME, how to figure out the pid of the program asking for the
-       * filesystem operation? */
-      ctx->pid = 0;
-    }
-
   ctx->fuse = fuse;
   ctx->private_data = ctx->fuse ? ctx->fuse->private_data : NULL;
 
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