From 0f5c35260be47064b275b560f759d8ec2145b9b6 Mon Sep 17 00:00:00 2001
From: Gregory Nutt <gnutt@nuttx.org>
Date: Tue, 12 May 2015 07:47:32 -0600
Subject: [PATCH] Local sockets: Local stream sockets had problem of double
 releasing pipes (both server and client attempt release), which causes wrong
 pipe pair being closed in multi-client case. Solve by adding per connection
 instance ID to pipe names.  From  Jussi Kivilinna (2015-05-12).

---
 net/local/local.h         |  2 ++
 net/local/local_accept.c  |  1 +
 net/local/local_bind.c    |  1 +
 net/local/local_connect.c | 21 +++++++++++++++++++++
 net/local/local_fifo.c    | 26 ++++++++++++++++++++++----
 5 files changed, 47 insertions(+), 4 deletions(-)

diff --git a/net/local/local.h b/net/local/local.h
index 5378d19b84..999f804ea0 100644
--- a/net/local/local.h
+++ b/net/local/local.h
@@ -143,6 +143,8 @@ struct local_conn_s
   int16_t lc_infd;             /* File descriptor of read-only FIFO (peers) */
   int16_t lc_outfd;            /* File descriptor of write-only FIFO (peers) */
   char lc_path[UNIX_PATH_MAX]; /* Path assigned by bind() */
+  int32_t lc_instance_id;      /* Connection instance ID for stream
+                                * server<->client connection pair */
 
 #ifdef CONFIG_NET_LOCAL_STREAM
   /* SOCK_STREAM fields common to both client and server */
diff --git a/net/local/local_accept.c b/net/local/local_accept.c
index 59ab57145f..00eaf0da3b 100644
--- a/net/local/local_accept.c
+++ b/net/local/local_accept.c
@@ -170,6 +170,7 @@ int psock_local_accept(FAR struct socket *psock, FAR struct sockaddr *addr,
 
               strncpy(conn->lc_path, client->lc_path, UNIX_PATH_MAX-1);
               conn->lc_path[UNIX_PATH_MAX-1] = '\0';
+              conn->lc_instance_id = client->lc_instance_id;
 
               /* Open the server-side write-only FIFO.  This should not
                * block.
diff --git a/net/local/local_bind.c b/net/local/local_bind.c
index 675b495163..316fe3e2e9 100644
--- a/net/local/local_bind.c
+++ b/net/local/local_bind.c
@@ -109,6 +109,7 @@ int psock_local_bind(FAR struct socket *psock,
 
           (void)strncpy(conn->lc_path, unaddr->sun_path, UNIX_PATH_MAX-1);
           conn->lc_path[UNIX_PATH_MAX-1] = '\0';
+          conn->lc_instance_id = -1;
         }
     }
 
diff --git a/net/local/local_connect.c b/net/local/local_connect.c
index 714afe1838..99ea989edf 100644
--- a/net/local/local_connect.c
+++ b/net/local/local_connect.c
@@ -59,6 +59,26 @@
  * Private Functions
  ****************************************************************************/
 
+/****************************************************************************
+ * Name: local_generate_instance_id
+ ****************************************************************************/
+
+static int32_t local_generate_instance_id(void)
+{
+  static int32_t g_next_instance_id = 0;
+  int32_t id;
+
+  /* Called from local_connect with net_lock held. */
+
+  id = g_next_instance_id++;
+  if (g_next_instance_id < 0)
+    {
+      g_next_instance_id = 0;
+    }
+
+  return id;
+}
+
 /****************************************************************************
  * Name: _local_semtake() and _local_semgive()
  *
@@ -286,6 +306,7 @@ int psock_local_connect(FAR struct socket *psock,
                 client->lc_proto = conn->lc_proto;
                 strncpy(client->lc_path, unaddr->sun_path, UNIX_PATH_MAX-1);
                 client->lc_path[UNIX_PATH_MAX-1] = '\0';
+                client->lc_instance_id = local_generate_instance_id();
 
                 /* The client is now bound to an address */
 
diff --git a/net/local/local_fifo.c b/net/local/local_fifo.c
index 2d00f8caba..0e4b3d667c 100644
--- a/net/local/local_fifo.c
+++ b/net/local/local_fifo.c
@@ -80,8 +80,17 @@
 static inline void local_cs_name(FAR struct local_conn_s *conn,
                                  FAR char *path)
 {
-  (void)snprintf(path, LOCAL_FULLPATH_LEN-1, "%s" LOCAL_CS_SUFFIX,
-                 conn->lc_path);
+  if (conn->lc_instance_id < 0)
+    {
+      (void)snprintf(path, LOCAL_FULLPATH_LEN-1, "%s" LOCAL_CS_SUFFIX,
+                     conn->lc_path);
+    }
+  else
+    {
+      (void)snprintf(path, LOCAL_FULLPATH_LEN-1, "%s" LOCAL_CS_SUFFIX "%x",
+                     conn->lc_path, conn->lc_instance_id);
+    }
+
   path[LOCAL_FULLPATH_LEN-1] = '\0';
 }
 #endif /* CONFIG_NET_LOCAL_STREAM */
@@ -98,8 +107,17 @@ static inline void local_cs_name(FAR struct local_conn_s *conn,
 static inline void local_sc_name(FAR struct local_conn_s *conn,
                                  FAR char *path)
 {
-  (void)snprintf(path, LOCAL_FULLPATH_LEN-1, "%s" LOCAL_SC_SUFFIX,
-                 conn->lc_path);
+  if (conn->lc_instance_id < 0)
+    {
+      (void)snprintf(path, LOCAL_FULLPATH_LEN-1, "%s" LOCAL_SC_SUFFIX,
+                     conn->lc_path);
+    }
+  else
+    {
+      (void)snprintf(path, LOCAL_FULLPATH_LEN-1, "%s" LOCAL_SC_SUFFIX "%x",
+                     conn->lc_path, conn->lc_instance_id);
+    }
+
   path[LOCAL_FULLPATH_LEN-1] = '\0';
 }
 #endif /* CONFIG_NET_LOCAL_STREAM */