From c79ab46894053312f80390bf13a52c238a7d4704 Mon Sep 17 00:00:00 2001
From: dimitri staessens <dimitri.staessens@intec.ugent.be>
Date: Sun, 16 Oct 2016 09:38:01 +0200
Subject: lib, dev: Implement read/write options for flows

Added the missing implementation of setting read/write options for
flows. This allows applications to block the fast path for
remotes. IPCPs can use this to block the fast path for the N + 1 flow
when receiving remote deallocation requests.
---
 src/ipcpd/local/main.c |  2 ++
 src/lib/dev.c          | 17 +++++++++++++++++
 2 files changed, 19 insertions(+)

diff --git a/src/ipcpd/local/main.c b/src/ipcpd/local/main.c
index b8b3335c..4e500a8a 100644
--- a/src/ipcpd/local/main.c
+++ b/src/ipcpd/local/main.c
@@ -24,6 +24,7 @@
 #include "ipcp.h"
 #include <ouroboros/errno.h>
 #include <ouroboros/dev.h>
+#include <ouroboros/fcntl.h>
 #include <ouroboros/select.h>
 #include <ouroboros/ipcp-dev.h>
 #include <ouroboros/local-dev.h>
@@ -252,6 +253,7 @@ static int ipcp_local_flow_dealloc(int fd)
         pthread_rwlock_rdlock(&ipcpi.state_lock);
         pthread_rwlock_wrlock(&local_data.lock);
 
+        flow_cntl(local_data.in_out[fd], FLOW_F_SETFL, FLOW_O_WRONLY);
         local_data.in_out[fd] = -1;
 
         pthread_rwlock_unlock(&local_data.lock);
diff --git a/src/lib/dev.c b/src/lib/dev.c
index a3082a7d..77c2d06a 100644
--- a/src/lib/dev.c
+++ b/src/lib/dev.c
@@ -561,6 +561,7 @@ int flow_dealloc(int fd)
         ai.flows[fd].port_id = -1;
         shm_ap_rbuff_close(ai.flows[fd].rb);
         ai.flows[fd].rb = NULL;
+        ai.flows[fd].oflags = 0;
         ai.flows[fd].api = -1;
         if (ai.flows[fd].timeout != NULL) {
                 free(ai.flows[fd].timeout);
@@ -602,6 +603,10 @@ int flow_cntl(int fd, int cmd, int oflags)
                 return old;
         case FLOW_F_SETFL: /* SET FLOW FLAGS */
                 ai.flows[fd].oflags = oflags;
+                if (oflags & FLOW_O_WRONLY)
+                        shm_ap_rbuff_close_port(ai.rb, ai.flows[fd].port_id);
+                if (oflags & FLOW_O_RDWR)
+                        shm_ap_rbuff_open_port(ai.rb, ai.flows[fd].port_id);
                 pthread_rwlock_unlock(&ai.flows_lock);
                 pthread_rwlock_unlock(&ai.data_lock);
                 return old;
@@ -632,6 +637,12 @@ ssize_t flow_write(int fd, void * buf, size_t count)
                 return -ENOTALLOC;
         }
 
+        if (ai.flows[fd].oflags & FLOW_O_RDONLY) {
+                pthread_rwlock_unlock(&ai.flows_lock);
+                pthread_rwlock_unlock(&ai.data_lock);
+                return -EPERM;
+        }
+
         if (ai.flows[fd].oflags & FLOW_O_NONBLOCK) {
                 idx = shm_rdrbuff_write(ai.rdrb,
                                        ai.flows[fd].api,
@@ -1078,6 +1089,12 @@ int ipcp_flow_write(int fd, struct shm_du_buff * sdb)
         pthread_rwlock_rdlock(&ai.data_lock);
         pthread_rwlock_rdlock(&ai.flows_lock);
 
+        if (ai.flows[fd].oflags & FLOW_O_RDONLY) {
+                pthread_rwlock_unlock(&ai.flows_lock);
+                pthread_rwlock_unlock(&ai.data_lock);
+                return -EPERM;
+        }
+
         if (ai.flows[fd].rb == NULL) {
                 pthread_rwlock_unlock(&ai.flows_lock);
                 pthread_rwlock_unlock(&ai.data_lock);
-- 
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