Adds OS internal functions nx_send(), ns_recv(), and nx_recvfrom() which are functionally equivalent to send(), recv(), and recvfrom() except that they do not set the errno variable and do not cause cancellation points.

fs/vfs/fs_read.c

@@ -48,6 +48,7 @@
 #include <errno.h>
 
 #include <nuttx/cancelpt.h>
+#include <nuttx/net/net.h>
 
 #include "inode/inode.h"
 
@@ -145,7 +146,11 @@ ssize_t read(int fd, FAR void *buf, size_t nbytes)
        * the errno variable.
        */
 
-      ret = recv(fd, buf, nbytes, 0);
+      ret = nx_recv(fd, buf, nbytes, 0);
+      if (ret < 0)
+        {
+          goto errout;
+        }
 #else
       /* No networking... it is a bad descriptor in any event */
 

fs/vfs/fs_write.c

@@ -52,6 +52,7 @@
 #endif
 
 #include <nuttx/cancelpt.h>
+#include <nuttx/net/net.h>
 
 #include "inode/inode.h"
 
@@ -167,11 +168,13 @@ ssize_t write(int fd, FAR const void *buf, size_t nbytes)
 #endif
     {
 #if defined(CONFIG_NET_TCP) && CONFIG_NSOCKET_DESCRIPTORS > 0
-      /* Write to a socket descriptor is equivalent to send with flags == 0.
-       * Note that send() will set the errno on failure.
-       */
+      /* Write to a socket descriptor is equivalent to send with flags == 0. */
 
-      ret = send(fd, buf, nbytes, 0);
+      ret = nx_send(fd, buf, nbytes, 0);
+      if (ret < 0)
+        {
+          goto errout;
+        }
 #else
       ret = -EBADF;
       goto errout;