- djm@cvs.openbsd.org 2006/04/16 00:54:10

     [sftp-client.c]
     avoid making a tiny 4-byte write to send the packet length of sftp
     commands, which would result in a separate tiny packet on the wire by
     using atomiciov(writev, ...) to write the length and the command in one
     pass; ok deraadt@

1 files changed, 8 insertions, 5 deletions

diff --git a/sftp-client.c b/sftp-client.c
index c71c66f33..8778439b9 100644
--- a/sftp-client.c
+++ b/sftp-client.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: sftp-client.c,v 1.64 2006/03/30 09:58:16 djm Exp $ */
+/* $OpenBSD: sftp-client.c,v 1.65 2006/04/16 00:54:10 djm Exp $ */
 /*
  * Copyright (c) 2001-2004 Damien Miller <djm@openbsd.org>
  *
@@ -61,16 +61,19 @@ static void
 send_msg(int fd, Buffer *m)
 {
         u_char mlen[4];
+        struct iovec iov[2];
 
         if (buffer_len(m) > SFTP_MAX_MSG_LENGTH)
                 fatal("Outbound message too long %u", buffer_len(m));
 
         /* Send length first */
         put_u32(mlen, buffer_len(m));
-        if (atomicio(vwrite, fd, mlen, sizeof(mlen)) != sizeof(mlen))
-                fatal("Couldn't send packet: %s", strerror(errno));
-
-        if (atomicio(vwrite, fd, buffer_ptr(m), buffer_len(m)) != buffer_len(m))
+        iov[0].iov_base = mlen;
+        iov[0].iov_len = sizeof(mlen);
+        iov[1].iov_base = buffer_ptr(m);
+        iov[1].iov_len = buffer_len(m);
+        
+        if (atomiciov(writev, fd, iov, 2) != buffer_len(m) + sizeof(mlen))
                 fatal("Couldn't send packet: %s", strerror(errno));
 
         buffer_clear(m);