From cc4d09423a7ea4cc2c11c41b836829691110c17d Mon Sep 17 00:00:00 2001
From: Joel Cunningham <joel.cunningham@me.com>
Date: Tue, 22 Sep 2015 08:36:27 -0500
Subject: [PATCH] Add writev function

This commit adds compatibility with POSIX writev according to the Open
Group specification:
http://pubs.opengroup.org/onlinepubs/009695399/functions/writev.html

Implementation maps to sendmsg in the same manner that write() maps to
send()
---
 src/api/sockets.c          | 15 +++++++++++++++
 src/include/lwip/sockets.h |  3 +++
 2 files changed, 18 insertions(+)

diff --git a/src/api/sockets.c b/src/api/sockets.c
index 04a4ff37..01c8ad9b 100644
--- a/src/api/sockets.c
+++ b/src/api/sockets.c
@@ -1271,6 +1271,21 @@ lwip_write(int s, const void *data, size_t size)
   return lwip_send(s, data, size, 0);
 }
 
+int
+lwip_writev(int s, const struct iovec *iov, int iovcnt)
+{
+  struct msghdr msg;
+  
+  msg.msg_name = NULL;
+  msg.msg_namelen = 0;
+  msg.msg_iov = (struct iovec *)iov;
+  msg.msg_iovlen = iovcnt;
+  msg.msg_control = NULL;
+  msg.msg_controllen = 0;
+  msg.msg_flags = 0;
+  return lwip_sendmsg(s, &msg, 0);
+}
+
 /**
  * Go through the readset and writeset lists and see which socket of the sockets
  * set in the sets has events. On return, readset, writeset and exceptset have
diff --git a/src/include/lwip/sockets.h b/src/include/lwip/sockets.h
index a7b6ff41..19eee9ef 100644
--- a/src/include/lwip/sockets.h
+++ b/src/include/lwip/sockets.h
@@ -470,6 +470,7 @@ void lwip_socket_thread_cleanup(void); /* LWIP_NETCONN_SEM_PER_THREAD==1: destro
 #if LWIP_POSIX_SOCKETS_IO_NAMES
 #define lwip_read         read
 #define lwip_write        write
+#define lwip_writev       writev
 #undef lwip_close
 #define lwip_close        close
 #define closesocket(s)    close(s)
@@ -498,6 +499,7 @@ int lwip_sendto(int s, const void *dataptr, size_t size, int flags,
     const struct sockaddr *to, socklen_t tolen);
 int lwip_socket(int domain, int type, int protocol);
 int lwip_write(int s, const void *dataptr, size_t size);
+int lwip_writev(int s, const struct iovec *iov, int iovcnt);
 int lwip_select(int maxfdp1, fd_set *readset, fd_set *writeset, fd_set *exceptset,
                 struct timeval *timeout);
 int lwip_ioctl(int s, long cmd, void *argp);
@@ -527,6 +529,7 @@ int lwip_fcntl(int s, int cmd, int val);
 #if LWIP_POSIX_SOCKETS_IO_NAMES
 #define read(s,mem,len)                           lwip_read(s,mem,len)
 #define write(s,dataptr,len)                      lwip_write(s,dataptr,len)
+#define writev(s,iov,iovcnt)                      lwip_writev(s,iov,iovcnt)
 #define close(s)                                  lwip_close(s)
 #define fcntl(s,cmd,val)                          lwip_fcntl(s,cmd,val)
 #define ioctl(s,cmd,argp)                         lwip_ioctl(s,cmd,argp)