lib: dev: implementation of flow_cntl

allows setting the oflags to make flow_read and flow_write blocking or
non-blocking (FLOW_O_NONBLOCK).

4 files changed, 39 insertions, 10 deletions

diff --git a/include/ouroboros/dev.h b/include/ouroboros/dev.h
index e857e211..d8e65144 100644
--- a/include/ouroboros/dev.h
+++ b/include/ouroboros/dev.h
@@ -31,7 +31,7 @@
 
 /* These calls should be removed once we write the ouroboros OS. */
 int     ap_init(char * ap_name);
-void    ap_fini();
+void    ap_fini(void);
 
 /* Returns file descriptor */
 int     ap_reg(char ** difs, size_t difs_size);
diff --git a/include/ouroboros/flow.h b/include/ouroboros/flow.h
index ff9085f7..380c671b 100644
--- a/include/ouroboros/flow.h
+++ b/include/ouroboros/flow.h
@@ -34,6 +34,9 @@
 
 #define FLOW_O_INVALID  (FLOW_O_WRONLY | FLOW_O_RDWR)
 
+#define FLOW_F_GETFL    00000001
+#define FLOW_F_SETFL    00000002
+
 enum flow_state {
         FLOW_NULL = 0,
         FLOW_ALLOCATED,
diff --git a/src/lib/dev.c b/src/lib/dev.c
index 24e688ef..0adc2364 100644
--- a/src/lib/dev.c
+++ b/src/lib/dev.c
@@ -38,7 +38,7 @@
 struct flow {
         struct shm_ap_rbuff * rb;
         int                   port_id;
-        uint32_t              oflags;
+        int                   oflags;
 
         /* don't think this needs locking */
 };
@@ -52,7 +52,6 @@ struct ap_data {
         struct flow           flows[AP_MAX_FLOWS];
 } * _ap_instance;
 
-
 int ap_init(char * ap_name)
 {
         int i = 0;
@@ -105,7 +104,7 @@ int ap_init(char * ap_name)
         return 0;
 }
 
-void ap_fini()
+void ap_fini(void)
 {
         int i = 0;
 
@@ -402,7 +401,16 @@ int flow_dealloc(int fd)
 
 int flow_cntl(int fd, int cmd, int oflags)
 {
-        return -1;
+        int old = _ap_instance->flows[fd].oflags;
+        switch (cmd) {
+        case FLOW_F_GETFL: /* GET FLOW FLAGS */
+                return _ap_instance->flows[fd].oflags;
+        case FLOW_F_SETFL: /* SET FLOW FLAGS */
+                _ap_instance->flows[fd].oflags = oflags;
+                return old;
+        default:
+                return FLOW_O_INVALID; /* unknown command */
+        }
 }
 
 ssize_t flow_write(int fd, void * buf, size_t count)
@@ -417,9 +425,17 @@ ssize_t flow_write(int fd, void * buf, size_t count)
         if (index == -1)
                 return -1;
 
-        if (shm_ap_rbuff_write(_ap_instance->flows[fd].rb, &e) < 0) {
-                shm_release_du_buff(_ap_instance->dum, index);
-                return -EPIPE;
+        if (_ap_instance->flows[fd].oflags & FLOW_O_NONBLOCK)
+        {
+                if (shm_ap_rbuff_write(_ap_instance->flows[fd].rb, &e) < 0) {
+                        shm_release_du_buff(_ap_instance->dum, index);
+                        return -EPIPE;
+                }
+
+                return 0;
+        } else {
+                while (shm_ap_rbuff_write(_ap_instance->flows[fd].rb, &e) < 0)
+                        ;
         }
 
         return 0;
@@ -430,9 +446,18 @@ ssize_t flow_read(int fd, void * buf, size_t count)
         struct rb_entry * e = NULL;
         int n;
         uint8_t * sdu;
-        /* FIXME: move this to a thread  */
-        while (e == NULL || e->port_id != _ap_instance->flows[fd].port_id)
+
+        if (_ap_instance->flows[fd].oflags & FLOW_O_NONBLOCK) {
                 e = shm_ap_rbuff_read(_ap_instance->rb);
+        } else {
+                /* FIXME: move this to a thread  */
+                while (e == NULL ||
+                       e->port_id != _ap_instance->flows[fd].port_id)
+                        e = shm_ap_rbuff_read(_ap_instance->rb);
+        }
+
+        if (e == NULL)
+                return -1;
 
         n = shm_du_map_read_sdu(&sdu,
                                 _ap_instance->dum,
diff --git a/src/lib/shm_ap_rbuff.c b/src/lib/shm_ap_rbuff.c
index 34583d8e..aab6d78b 100644
--- a/src/lib/shm_ap_rbuff.c
+++ b/src/lib/shm_ap_rbuff.c
@@ -242,6 +242,7 @@ int shm_ap_rbuff_write(struct shm_ap_rbuff * rb, struct rb_entry * e)
 
         return 0;
 }
+
 struct rb_entry * shm_ap_rbuff_read(struct shm_ap_rbuff * rb)
 {
         struct rb_entry * e = NULL;